VECTORS FOR DELIVERY OF LIGHT SENSITIVE PROTEINS AND METHODS OF USE
Provided herein are compositions and methods for gene and etiology-nonspecific and circuit-specific treatment of diseases, utilizing vectors for delivery of light-sensitive proteins to diseased and normal cells and tissues of interest.
This application claims the benefit of U.S. Provisional Application Nos. 61/054,571 filed May 20, 2008, 61/199,241 filed Nov. 14, 2008, and 61/200,430 filed Nov. 26, 2008, which applications are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTIONA gene-delivery therapy to treat a disease or disorder independent of treating an underlying mutation could have potential value. Methods capable of controlling, regulating, and/or driving specific neural circuits so as to mediate naturalistic neural responses and high resolution perception and control could also be of enormous potential therapeutic value. Neurons are an example of a type of cell that uses the electrical currents created by depolarization to generate communication signals (e.g., nerve impulses). Other electrically excitable cells include skeletal muscle, cardiac muscle, and endocrine cells. Neurons use rapid depolarization to transmit signals throughout the body and for various purposes, such as motor control (e.g., muscle contractions), sensory responses (e.g., touch, hearing, and other senses) and computational functions (e.g., brain functions). By facilitating or inhibiting the flow of positive or negative ions through cell membranes, the cell can be briefly depolarized, depolarized and maintained in that state, or hyperpolarized. Thus, the control of the depolarization of cells can be beneficial for a number of different purposes, including visual, muscular and sensory control. Light-sensitive protein channels, pumps, and receptors can permit millisecond-precision optical control of cells. Although light-sensitive proteins in combination with light can be used to control the flow of ions through cell membranes, targeting and delivery remain to be addressed for specific diseases, disorders, and circuits.
SUMMARY OF THE INVENTIONIn one aspect, the invention provides a recombinant nucleic acid comprising a nucleic acid encoding a light-sensitive protein operatively linked to a metabotropic glutamate receptor 6 (mGluR6) regulatory sequence or fragment thereof. In one embodiment the light-sensitive protein can be selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In another embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the mGluR6 regulatory sequence fragment comprises less than about 1000, less than about 750, less than about 500, less than about 250, or less than about 100 base pairs. In a related embodiment the mGluR6 regulatory sequence or fragment thereof is a mGluR6 promoter or enhancer. In a specific related embodiment the nucleic acid further comprises a green fluorescent protein. In another embodiment the nucleic acid is encapsidated within a recombinant adeno-associated virus (AAV). In certain embodiments, the recombinant AAV is of a combinatorial hybrid of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more serotypes or mutants thereof. In certain embodiments, the recombinant adeno-associated virus is of a serotype selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof. In a related embodiment, the nucleic acid is encapsidated within a recombinant virus selected from the group consisting of recombinant adeno-associated virus (AAV), recombinant retrovirus, recombinant lentivirus, and recombinant poxvirus.
In another aspect the invention provides a vector comprising a nucleic acid encoding a light-sensitive protein, said nucleic acid operatively linked to a metabotropic glutamate receptor 6 (mGluR6) regulatory sequence or fragment thereof. In one embodiment the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In a relate embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the mGluR6 regulatory sequence fragment is less than about 1000, less than about 750, less than about 500, less than about 250, or less than about 100 base pairs. In a related embodiment the mGluR6 regulatory sequence fragment is represented by the sequence in
In another aspect the present invention provides a method of treating a subject suffering from a disease or disorder of the eye comprising introducing into an affected eye a recombinant adeno-associated virus (AAV) comprising a light-sensitive protein operatively linked to a metabotropic glutamate receptor 6 regulatory sequence (mGluR6) or fragment thereof. In one embodiment the disease or disorder of the eye is caused by photoreceptor cell degeneration. In another embodiment the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In a related embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the mGluR6 promoter fragment is less than about 1000, less than about 750, less than about 500, less than about 250, or less than about 100 base pairs. In a related embodiment the mGluR6 promoter fragment is represented by the sequence in
In another aspect the present invention provides a method of expressing an exogenous nucleic acid in a retinal bipolar cell (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) comprising introducing into a retina a vector comprising the exogenous nucleic operatively linked to a retinal bipolar (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) cell-specific regulatory sequence wherein the method results in at least about a 25-30% transduction efficiency. In other embodiment, such method results in at least about a 10% transduction efficiency. In one embodiment the method results in at least about 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% transduction efficiency. In a related embodiment the transduction efficiency is measured by quantifying the total number of retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) infected. In another embodiment the exogenous nucleic acid comprises a light-sensitive protein. In a related embodiment the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In a specific embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the regulatory sequence comprises a metabotropic glutamate receptor 6 regulatory sequence (mGluR6) or a fragment thereof. In a related embodiment the mGluR6 regulatory sequence fragment is less than about 1000, less than about 750, less than about 500, less than about 250, or less than about 100 base pairs. In a specific embodiment the mGluR6 regulatory sequence fragment is represented by the sequence in
In yet another aspect, the present invention provides a method of introducing an exogenous nucleic acid into the nucleus of a retinal cell comprising introducing a vector comprising an exogenous nucleic acid operatively linked to a retinal cell-specific regulatory sequence into a retinal cell, wherein the vector is specifically designed to avoid ubiquitin-mediated protein degradation. In one embodiment the degradation is proteasome-mediated. In another embodiment the exogenous nucleic acid comprises a light-sensitive protein. In a related embodiment the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In another related embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the retinal cell is a retinal bipolar cell (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In a related embodiment the regulatory sequence comprises a metabotropic glutamate receptor 6 promoter (mGluR6 promoter) or fragment thereof. In another embodiment the mGluR6 fragment is less than 1000, 750, 500, 250, or 100 base pairs. In another embodiment the mGluR6 promoter fragment is represented by the sequence in
In another aspect the present invention provides a method of transducing a retinal bipolar cell (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) comprising introducing into a retina a vector comprising an exogenous nucleic acid operatively linked to a regulatory sequence. In one embodiment the regulatory sequence is a non-cell type specific promoter. In another embodiment the regulatory sequence is a guanine nucleotide binding protein alpha activating activity polypeptide 0 (GNAO1) promoter or a fusion of the cytomegalovirus (CMV) immediate early enhancer and the bovine β-actin promoter plus intron1-exon1 junction (CBA, smCBA). In another embodiment the exogenous nucleic acid comprises a light-sensitive protein. In a related embodiment the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In another related embodiment the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In another embodiment the vector is selected from the group consisting of recombinant adeno-associated virus (AAV), recombinant retrovirus, recombinant lentivirus, and recombinant poxvirus. In a related embodiment the vector is a recombinant adeno-associated viral vector (AAV). In another embodiment the AAV is of a serotype selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof. In certain embodiments, the recombinant AAV is of a combinatorial hybrid of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more serotypes or mutants thereof. In a related embodiment the AAV comprises a mutated capsid protein. In another embodiment the capsid protein comprises a mutated tyrosine residue. In another embodiment the mutated tyrosine residue is selected from the group consisting of Y252F, Y272F, Y444F, Y500F, Y700F, Y704F, Y730F, Y275F, Y281F, Y508F, Y576F, Y612G, Y673F and Y720F. In another embodiment the mutated capsid protein comprises a tyrosine residue mutated to a phenylalanine. In another embodiment the vector is introduced using intravitreal injection, subretinal injection, and/or ILM peel.
INCORPORATION BY REFERENCEAll publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
The present invention provides recombinant nucleic acids encoding light-sensitive proteins, viral and non-viral vectors for the delivery of recombinant nucleic acids encoding light-sensitive proteins, and methods for delivery of light-sensitive proteins.
Light-sensitive proteins are proteins that belong to the opsin family and include vertebrate (animal) and invertebrate rhodopsins. The animal opsins, rhodopsins, are G-protein coupled receptors (GPCRs) with 7-transmembrane helices which can regulate the activity of ion channels. Invertebrate rhodopsins are usually not GPCRs, but are light-sensitive or light-activated ion pumps or ion channels.
An algal opsin such as channelrhodopsin (ChR2) from Chlamydomonas reinhardtii allows blue light-induced action potentials to be triggered with millisecond-precision in cells due to depolarizing cation flux through a light-gated pore. An archael opsin such as halorhodopsin Natronomonas pharaonis allows for light-activated chloride pumping; the pump can be hyperpolarized and inhibited from firing action potentials when exposed to yellow light. Use of such light-sensitive opsins allows for temporal and spatial regulation of neuronal firing activity.
As referred to herein, a “light-sensitive” protein includes channelrhodopsins (ChR1, ChR2), halorhodopsins (NpHR), melanopsins, pineal opsins, bacteriorhodopsin, and variants thereof. A light-sensitive protein of this invention can occur naturally in plant, animal, archaebacterial, algal, or bacterial cells, or can alternatively be created through laboratory techniques.
Channelrhodopsins ChR1 (GenBank accession number AB058890/AF385748;
In some embodiments hybrid or chimeric channelrhodopsins can be created and used by combining different portions of the ChR1 and ChR2 proteins.
In one embodiment a hybrid or chimeric channelrhodopsin can be created and used by replacing the N-terminal segments of ChR2 with the homologous counterparts of ChR1 (and vice-versa). In some embodiments the hybrid channelrhodopsins result in a shift of sensitivity into a different wavelength spectrum (for example into the red wavelength spectrum) with negligible desensitization and slowed turning-on and turning-off kinetics.
In another embodiment a ChR1 (amino acids 1-345) and ChR2 (amino acids 1-315) hybrid/chimera can be created and used.
In yet another embodiment ChR1-ChR2 hybrids/chimeras retaining the N-terminal portion of ChR1 and replacing the C-terminal portion with the corresponding ChR2 segment can be created and used. In specific embodiments hybrids/chimeras of ChR1 and ChR2 can be constructed and utilized including mutant residues around the retinal binding pockets of the chimeras. In exemplary embodiments the following chimeras can be created and used:
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- a. ChD: a hybrid/chimera of a ChR1 N-terminal portion and a ChR2 C-terminal portion where the crossover site is at a point of homology at helixD of the two channelrhodopsins
- b. ChEF: a hybrid/chimera of a ChR1 N-terminal portion and a ChR2 C-terminal portion where the crossover site is at the loop between helices E and F of the two channelrhodopsins
- c. ChIEF: a variant of the ChEF chimera with isoleucine 170 mutated to valine
- d. ChF: a hybrid/chimera of a ChR1 N-terminal portion and a ChR2 C-terminal portion where the crossover site is at the end of helix F of the two channelrhodopsins.
In some embodiments the chimeras retain the reduced inactivation of ChR1 in the presence of persistent light, but can allow the permeation of sodium and potassium ions in addition to protons. In other embodiments the chimeras can improve the kinetics of the channel by enhancing the rate of the channel closure after stimulation.
In some embodiments other ChR1 and ChR2 variants can be engineered. In specific embodiments single or multiple point mutations to the ChR2 protein can result in ChR2 variants. In exemplary embodiments, mutations at the C128 location of ChR2 can result in altered channel properties. In related embodiments, C128A, C128S, and C128T ChR2 mutations can result in greater overall mean open times (Berndt, 2009). In other related embodiments, ChR2 variants can result in altered kinetics.
In another embodiment, a VChR1 can be used (GenBank accession number EU622855).
In specific embodiments a mammalian codon optimized version of ChR2 is utilized (
NpHR (Halorhodopsin) (GenBank accession number EF474018;
In one embodiment NpHR variants are utilized. In one specific embodiment eNpHR (enhanced NpHR) is utilized. Addition of the amino acids FCYENEV to the NpHR C-terminus along with the signal peptide from the β subunit of the nicotinic acetylcholine receptor to the NpHR N-terminus results in the construction of eNpHR.
Melanopsin (GenBank accession number 6693702;
Light-sensitive proteins may also include proteins that are at least about 10%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, or at least about 99% identical to the light-sensitive proteins ChR1, ChR2, NpHR and melanopsin. For example, the ChR2 protein may include proteins that are at least about 60%, at least about 70%, at least about 80%, at least about 90% or at least about 95% identical to ChR2. In addition, these proteins may include ChR2 that is photosensitive and can be activated by specific wavelengths of high intensity light.
In some embodiments, light-sensitive proteins can modulate signaling within neural circuits and bidirectionally control behavior of ionic conductance at the level of a single neuron. In some embodiments the neuron is a retinal neuron, a retinal bipolar cell (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), a retinal ganglion cell, a photoreceptor cell, or a retinal amacrine cell.
Adeno-Associated Viral VectorsThe present invention provides viral vectors comprising nucleic acids encoding a light-sensitive proteins and methods of use, as described herein.
Adeno-associated virus (AAV) is a small (25-nm), nonenveloped virus that packages a linear single-stranded DNA genome of 4.7 Kb. The small size of the AAV genome and concerns about potential effects of Rep on the expression of cellular genes led to the construction of AAV vectors that do not encode Rep and that lack the cis-active IEE, which is required for frequent site-specific integration. The ITRs are kept because they are the cis signals required for packaging. Thus, current recombinant AAV (rAAV) vectors persist primarily as extrachromosomal elements.
A variety of recombinant adeno-associated viral vectors (rAAV) may be used to deliver genes of interest to a cell and to effect the expression of a gene of interest, e.g., a gene encoding a light-sensitive protein. For example, rAAV can be used to express light-sensitive proteins, e.g., ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof or any light-sensitive protein described herein, in a target cell. At times herein, “transgene” is used to refer to a polynucleotide encoding a polypeptide of interest, wherein the polynucleotide is encapsidated in a viral vector (e.g., rAAV).
Adeno-associated viruses are small, single-stranded DNA viruses which require helper virus to facilitate efficient replication. The 4.7 kb genome of AAV is characterized by two inverted terminal repeats (ITR) and two open reading frames which encode the Rep proteins and Cap proteins, respectively. The Rep reading frame encodes four proteins of molecular weight 78 kD, 68 kD, 52 kD and 40 kD. These proteins function mainly in regulating AAV replication and rescue and integration of the AAV into a host cell's chromosomes. The Cap reading frame encodes three structural proteins of molecular weight 85 kD (VP 1), 72 kD (VP2) and 61 kD (VP3) (Berns, cited above) which form the virion capsid. More than 80% of total proteins in AAV virion comprise VP3.
The genome of rAAV is generally comprised of: (1) a 5′adeno-associated virus ITR, (2) a coding sequence (e.g., transgene) for the desired gene product (e.g., a light-sensitive protein) operatively linked to a sequence which regulates its expression in a cell (e.g., a promoter sequence such as a mGluR6 or fragment thereof), and (3) a 3′adeno-associated virus inverted terminal repeat. In addition, the rAAV vector may preferably contain a polyadenylation sequence.
Generally, rAAV vectors have one copy of the AAV ITR at each end of the transgene or gene of interest, in order to allow replication, packaging, and efficient integration into cell chromosomes. The ITR consists of nucleotides 1 to 145 at the 5′end of the AAV DNA genome, and nucleotides 4681 to 4536 (i.e., the same sequence) at the 3′end of the AAV DNA genome. The rAAV vector may also include at least 10 nucleotides following the end of the ITR (i.e., a portion of the “D region”).
The transgene sequence (e.g., the polynucleotide encoding a light-sensitive protein) can be of about 2 to 5 kb in length (or alternatively, the transgene may additionally contain a “stuffer” or “filler” sequence to bring the total size of the nucleic acid sequence between the two ITRs to between 2 and 5 kb). Alternatively, the transgene may be composed of repeated copies of the same or similar heterologous sequence several times (e.g., two nucleic acid molecules which encode one or more light-sensitive proteins separated by a ribosome readthrough, or alternatively, by an Internal Ribosome Entry Site or “IRES”), or several different heterologous sequences (e.g., ChR2 and NpHR separated by a ribosome readthrough or an IRES; or any two ore more of the light-sensitive proteins described herein including but not limited to ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof).
Recombinant AAV vectors of the present invention may be generated from a variety of adeno-associated viruses, including for example, any of serotypes 1 through 12, as described herein. For example, ITRs from any AAV serotype are expected to have similar structures and functions with regard to replication, integration, excision and transcriptional mechanisms.
In some embodiments, a cell-type specific promoter (or other regulatory sequence such as an enhancer) is employed to drive expression of a gene of interest, e.g., a light-sensitive protein, ChR2, etc., in one or more specific cell types. In other cases, Within certain embodiments of the invention, expression of the light-sensitive transgene may be accomplished by a separate promoter (e.g., a viral, eukaryotic, or other promoter that facilitates expression of an operatively linked sequence in an eukaryotic cell, particularly a mammalian cell). Representative examples of suitable promoters in this regard include a mGluR6 promoter, a GNA01 promoter, a CBA/smCBA (fusion of the CMV immediate early enhancer and bovine beta actin promoter plus intro1-exon1 junction) promoter, CBA promoter (chicken beta actin), CMV promoter, RSV promoter, SV40 promoter, MoMLV promoter, or derivatives, mutants and/or fragments thereof. Promoters and other regulatory sequences are further described herein.
Other promoters that may similarly be utilized within the context of the present invention include cell or tissue specific promoters (e. g, a rod, cone, or ganglia derived promoter), or inducible promoters. Representative examples of suitable inducible promoters include inducible promoters sensitive to an antibiotic, e.g., tetracycline-responsive promoters such as “tet-on” and/or “tet-off” promoters. Inducible promoters may also include promoters sensitive to chemicals other than antibiotics.
The rAAV vector may also contain additional sequences, for example from an adenovirus, which assist in effecting a desired function for the vector. Such sequences include, for example, those which assist in packaging the rAAV vector into virus particles.
Packaging cell lines suitable for producing adeno-associated viral vectors may be accomplished given available techniques (see e.g., U.S. Pat. No. 5,872,005). Methods for constructing and packaging rAA7I vectors are described in, for example, WO 00/54813.
Flanking the rep and cap open reading frames at the 5′ and 3′ ends are 145 bp inverted terminal repeats (ITRs), the first 125 bp of which are capable of forming Y- or T-shaped duplex structures. The two ITRs are the only cis elements essential for AAV replication, rescue, packaging and integration of the AAV genome. There are two conformations of AAV ITRs called “flip” and “flop”. These differences in conformation originated from the replication model of adeno-associated virus which uses the ITR to initiate and reinitiate the replication (R. O. Snyder et al, 1993, J. Virol., 67:6096-6104 (1993); K. I. Berns, 1990 Microbiological Reviews, 54:316-329). The entire rep and cap domains can be excised and replaced with a therapeutic or reporter transgene.
In some embodiments self-complementary AAV vectors are used. Self-complementary vectors have been developed to circumvent rate-limiting second-strand synthesis in single-stranded AAV vector genomes and to facilitate robust transgene expression at a minimal dose. In specific embodiments a self-complementary AAV of any serotype or hybrid serotype or mutant serotype, or mutant hybrid serotype increases expression of a light-sensitive protein such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, or more than 200%, when compared to a non-self complementary rAAV of the same serotype.
Adeno-Associated Viral SerotypesIn one embodiment the vector comprises a recombinant AAV of a particular serotype, either naturally occurring or engineered.
AAVs have been found in many animal species, including primates, canine, fowl and human.
Viral serotypes are strains of microorganisms having a set of recognizable antigens in common. There are several known serotypes of AAV, and the efficacy of transfection or transduction within the retina may vary as a function of the specific serotype and the nature of the target cells. rAAV, or a specific serotype of rAAV or AAV, may provide tissue-specific or cell-type specific tropism for gene delivery to retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). While rAAV and/or AAV is likely a relatively safe method to deliver a transgene to a target tissue, the efficacy of delivery, and possibly the safety of delivery, may depend on the coat proteins of the AAV. The protein coat, or capsid, determines which cells can take up the viral payload. Different AAV serotypes, i.e., viruses that differ in their proteins coats or capsids, may differ in their tissue tropism and ability to transduce targeted cells. Transgenes can be packaged within AAV particles with many functionally different coat proteins, or capsids. These different capsids are what define the serotype and may contribute (entirely or in part) to its ability to transduce particular cell types. The entry of the viral vector begins with the interaction of the capsid and the target cell surface proteins. Without wishing to be bound by theory, it is at this point in the transduction pathway that different serotypes may significantly influence the efficiency of transgene delivery.
In certain embodiments the AAV vector is of a serotype or variant/mutant thereof including but not limited to: AAV1 (GenBank accession number AY724675), AAV2 (GenBank accession number AF043303), AAV3, AAV4, AAV5 (GenBank accession number M61166), AAV6, AAV7 (GenBank accession number AF513851), AAV8 (GenBank accession number AF513852), AAV9 (GenBank accession number AX753250), AAV10, AAV11 (GenBank accession number AY631966), or AAV12 (GenBank accession number DQ813647), or mutants, hybrids, or fragments thereof. In certain embodiments the AAV vector comprises one or more, two or more, three or more, four or more, or five or more of the following serotypes: AAV1 (GenBank accession number AY724675), AAV2 (GenBank accession number AF043303), AAV3, AAV4, AAV5 (GenBank accession number M61166), AAV6, AAV7 (GenBank accession number AF513851), AAV8 (GenBank accession number AF513852), AAV9 (GenBank accession number AX753250), AAV10, AAV11 (GenBank accession number AY631966), or AAV12 (GenBank accession number DQ813647), or mutants, hybrids, or fragments thereof. In other embodiments, the AAV vector is of a natural serotype or variant/mutant thereof, heretofore yet undiscovered and uncharacterized.
In certain embodiments, the recombinant AAV is of a combinatorial hybrid of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more serotypes or mutants thereof.
In some embodiments, the AAV vector may be used to specifically transduce a specific cell type, e.g., retinal cells or retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In some cases, a specific serotype, e.g., AAV2, AAV5, AAV7 or AAV8, may be better than other serotypes at transducing a particular cell type (e.g., retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), neurons) or tissue. For example, a specific AAV serotype such as AAV2, AAV5, AAV7 or AAV8 may transduce a specific cell type, e.g., retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), with an increased transduction efficiency of at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, or more than 200%, when compared to a different AAV serotype. In some cases, a specific serotype e.g., AAV2, AAV5, AAV7 or AAV8, may permit transduction of at least 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of cells of a particular cell type, e.g., retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), or of cells within a particular tissue, e.g., retinal tissue.
There is a need in the art for AAV serotypes that can effectively transduce retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), particularly when such transduction enables the delivery and expression of a light-sensitive protein, e.g., ChR2. An important therapy to treat eye disorders or diseases (e.g., visual impairment, blindness), may involve using a particular AAV serotype to express light-sensitive proteins such as ChR2 in retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). For example, in a preferred embodiment, AAV5 or AAV7 serotypes are used to target expression of a gene of interest (e.g., a light-sensitive protein, ChR2, etc.) in retinal cells, e.g., retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In some cases, AAV5 and/or AAV7 may more efficiently transduce retinal cells, e.g., retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), than other AAV serotypes. For example, in some embodiments, the AAV5 and/or AAV7 serotypes, but not AAV1 serotype, are used to transduce retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In other cases AAV2 and/or AAV8 serotypes are used to transduce retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In some cases, a specific serotype, e.g., AAV2, AAV5, AAV7 or AAV8, may be generally applied to a tissue, e.g., retinal tissue, but then preferentially transduces a specific cell-type over another cell type.
In some cases, an AAV e.g., AAV2, AAV5, AAV7 or AAV8, that is introduced to the retina may preferentially transduce retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) so that the transgene is expressed more highly in retinal bipolar cells compared to other retinal cells. In some cases, the particular serotype e.g., AAV2, AAV5, AAV7 or AAV8, of the AAV may be the cause or contribute to the cause of such preferential transduction. In some cases, only a small subset of the bipolar cells are transduced.
In some embodiments, a specific serotype of AAV, e.g., AAV5 and/or AAV7 (or any other AAV serotype or mutant described herein) comprising a non-cell-type-specific promoter is used to drive expression of a light-sensitive protein in a particular cell type. In some cases, a specific serotype of AAV that has been demonstrated to preferentially transduce a particular cell type is used along with a cell-type specific promoter to drive expression of a protein of interest, e.g., a light-sensitive protein, in a specific cell-type.
The AAV ITR sequences and other AAV sequences employed in generating the minigenes, vectors, and capsids, and other constructs used in certain embodiments may be obtained from a variety of sources. For example, the sequences may be provided by presently identified human AAV types and AAV serotypes yet to be identified Similarly, AAVs known to infect other animals may also provide these ITRs employed in the molecules or constructs of this invention. Similarly, the capsids from a variety of serotypes of AAV may be “mixed and matched” with the other vector components. See, e.g., International Patent Publication No. WO01/83692, published Nov. 8, 2001, and incorporated herein by reference. A variety of these viral serotypes and strains are available from the American Type Culture Collection, Manassas, Va., or are available from a variety of academic or commercial sources. Alternatively, it may be desirable to synthesize sequences used in preparing the vectors and viruses of the invention using known techniques, which may utilize AAV sequences which are published and/or available from a variety of databases.
Adeno-Associated Viruses and Mutations of Surface-Exposed ResiduesRecombinant adeno-associated virus vectors are in use in several clinical trials, but relatively large vector doses are needed to achieve therapeutic benefits. Large vector doses may also trigger an immune response as a significant fraction of the vectors may fail to traffic efficiently to the nucleus and may be targeted for degradation by the host cell proteasome machinery. It has been reported that epidermal growth factor receptor protein tyrosine kinase (EGFR-PTK) signaling negatively affects transduction by AAV Serotype 2 vectors by impairing nuclear transport of the vectors (Zhong 2007). Tyrosine-phosphorylated AAV2 vectors enter but do not transduce effectively, in part because of the ubiquitination of AAV capsids followed by proteasome-mediated degradation. Point mutations in tyrosines in AAV2 may lead to high-efficiency transduction at lower virus titers (Zhong 2008). In one embodiment, tyrosine-mutated AAVs e.g., AAV2 or AAV8, are used in order to improve the efficiency of transduction of retinal cells, e.g., retinal bipolar cells (
In a related embodiment any one or more surface exposed residues other than tyrosine may be mutated to improve the transduction efficiency, tissue/cell-type tropism, expression characteristics, and titers needed for effective infection.
As described herein, modification and changes to the structure of the polynucleotides and polypeptides of wild-type rAAV vectors may result in improved rAAV virions possessing desirable characteristics. For example, mutated rAAV vectors may improve delivery of light-sensitive gene constructs to selected mammalian cell, tissues, and organs for the treatment, prevention, and prophylaxis of various diseases and disorders. Such approach may also provide a means for the amelioration of symptoms of such diseases, and to facilitate the expression of exogenous therapeutic and/or prophylactic polypeptides of interest via rAAV vector-mediated gene therapy. The mutated rAAV vectors may encode one or more proteins, e.g., the light-sensitive proteins, e.g., ChR2, described herein. The creation (or insertion) of one or more mutations into specific polynucleotide sequences that encode one or more of the light-sensitive proteins encoded by the disclosed rAAV constructs are provided herein. In certain circumstances, the resulting light-sensitive polypeptide sequence is altered by these mutations, or in other cases, the sequence of the polypeptide is unchanged by one or more mutations in the encoding polynucleotide to produce modified vectors with improved properties for effecting gene therapy in mammalian systems. As described herein, codon-optimization of the polynucleotide encoding the light-sensitive protein may also improve transduction efficiency.
The ubiquitin-proteasome pathway plays a role in AAV-intracellular trafficking. Substitution of surface exposed tyrosine residues on, for example, AAV2 or AAV8 capsids permits the vectors to either have limited ubiquitination or to escape ubiquitination altogether. The reduction in, or absence of, ubiquitination may help prevent the capsid from undergoing proteasome-mediated degradation. AAV or rAAV capsids can be phosphorylated at tyrosine residues by EGFR-PTK in an in vitro phosphorylation assay, and the phosphorylated AAV capsids retain their structural integrity. Although phosphorylated AAV vectors may enter cells as efficiently as their unphosphorylated counterparts, their transduction efficiency may be significantly impaired.
In some cases, a recombinant adeno-associated viral (rAAV) vector comprises a capsid protein with a mutated tyrosine residue which enables to the vector to have improved transduction efficiency of a target cell, e.g., a retinal bipolar cell (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells). In some cases, the rAAV further comprises a promoter (e.g., mGluR6, or fragment thereof) capable of driving the expression of a protein of interest in the target cell.
In some cases, expression in a specific cell type is further achieved by including a cell-type specific promoter described herein within the rAAV vector.
In one embodiment, a recombinant adeno-associated viral (rAAV) vector comprises at least a first capsid protein comprising at least a first phosphorylated tyrosine amino acid residue, and wherein said vector further comprises at least a first nucleic acid segment that encodes a light-sensitive protein operably linked to a promoter capable of expressing said segment in a host cell.
In one embodiment, a mutation may be made in any one or more of tyrosine residues of the capsid protein of AAV 1-12 or hybrid AAVs. In specific embodiments these are surface exposed tyrosine residues. In a related embodiment the tyrosine residues are part of the VP1, VP2, or VP3 capsid protein. In exemplary embodiments, the mutation may be made at one or more of the following amino acid residues of an AAV-VP3 capsid protein: Tyr252, Tyr272, Tyr444, Tyr500, Tyr700, Tyr704, Tyr730; Tyr275, Tyr281, Tyr508, Tyr576, Tyr612, Tyr673 or Tyr720. Exemplary mutations are tyrosine-to-phenylalanine mutations including, but not limited to, Y252F, Y272F, Y444F, Y500F, Y700F, Y704F, Y730F, Y275F, Y281F, Y508F, Y576F, Y612G, Y673F and Y720F. In a specific embodiment these mutations are made in the AAV2 serotype. In some cases, an AAV2 serotype comprises a Y444F mutation and/or an AAV8 serotype comprises a Y733F mutation, wherein 444 and 733 indicate the location of a point tyrosine mutation of the viral capsid. In further embodiments, such mutated AAV2 and AAV8 serotypes encode a light-sensitive protein, e.g., ChR2, and may also comprise a regulatory sequence (e.g., mGluR6) to drive expression of such light-sensitive protein.
In a related embodiment, 1, 2, 3, 4, 5, 6, or 7 mutations are made to the tyrosine residue on an AAV 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or hybrid serotype. In one exemplary embodiment, 3 tyrosines are mutated to create an AAV serotype with a triple mutation consisting of: Y444F, Y500F, and Y730F.
The rAAV vectors of the present invention may be comprised within an adeno-associated viral particle or infectious rAAV virion, including for example, virions selected from the group consisting of an AAV serotype 1, an AAV serotype 2, an AAV serotype 3, an AAV serotype 4, an AAV serotype 5 and an AAV serotype 6, an AAV serotype 7, an AAV serotype 8, an AAV serotype 9, an AAV serotype 10, an AAV serotype 11, an AAV serotype 12, or a hybrid AAV serotype.
The rAAV vectors of the present invention may also be comprised within an isolated mammalian host cell, including for example, human, primate, murine, feline, canine, porcine, ovine, bovine, equine, epine, caprine and lupine host cells. The rAAV vectors may be comprised within an isolated mammalian host cell such as a human endothelial, epithelial, vascular, liver, lung, heart, pancreas, intestinal, kidney, muscle, bone, neural, blood, or brain cell.
In certain embodiments the transduction efficiency of an AAV comprising a mutated capsid protein (e.g., a mutation of a tyrosine residue described herein) expressing a light-sensitive protein such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof is increased by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, or more than 200%, when compared to a wild-type AAV expressing a light-sensitive protein. This disclosure also provides mutated rAAV vectors (e.g., the AAV2 Y444F vector or the AAV8Y733F vector) capable of transducing at least 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) bipolar cells. The improvement in transduction created by the mutated capsid may permit transduction of bipolar cells by intravitreal injection. For example, in some embodiments, a mutated rAAV vector or a rAAV combinatorial serotype hybrid vector or a mutated combinatorial serotype hybrid rAAV vector may be capable of transducing at least 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) is introduced to the retina by intravitreal injection. In a specific embodiment, only a subset of the retinal bipolar cells is transduced. In another specific embodiment only the highly sensitive bipolar cells are transduced.
In certain embodiments the ubiquitin or proteasome-mediated degradation of an AAV comprising a capsid protein with a mutation expressing a light-sensitive protein, such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof, is decreased by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90%, when compared to a wild-type AAV expressing a light-sensitive protein.
Other Gene Delivery VectorsAny of a variety of other vectors adapted for expression of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof or any light-sensitive protein in a cell of the eye, particularly within a retinal cell, more particularly within a non-photoreceptor cell (e.g. amacrine cells, retinal ganglion cells, retinal bipolar cells, (ON or OFF retinal bipolar cells; rod and cone bipolar cells)), are within the scope of the present invention. Gene delivery vectors can be viral (e.g., derived from or containing sequences of viral DNA or RNA, preferably packaged within a viral particle), or non-viral (e.g., not packaged within a viral particle, including “naked” polynucleotides, nucleic acid associated with a carrier particle such as a liposome or targeting molecule, and the like).
Other exemplary gene delivery vectors are described below.
Recombinant Adenoviral Vectors (Ad): in other embodiments, the gene delivery vector is a recombinant adenoviral vector. U.S. Pat. No. 6,245,330 describes recombinant adenoviruses which may be suitable for use in the invention. Ad vectors do not integrate into the host cell genome, particularly preferred when short term gene is required, typically about 14 days. Thus, use of Ad vectors can require repeated intraocular injections to treat a retinal disease which continues over decades in the average patient.
The viral tropism of Ad and AAV in the retina is can be different. The subset of cells that are transduced by the vector is usually a receptor-mediated event. Ad vectors have been shown to primarily transduce retinal Muller cells and Retinal pigment epithelial cells following injection. AAV vectors are very efficient at transferring their genetic payload to retinal photoreceptor and non-photoreceptor cells when injected into the eye.
Retroviral gene delivery vectors: the gene delivery vectors of the invention can be a retroviral gene delivery vector adapted to express a selected gene (s) or sequence (s) of interest (e.g., ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof). Retroviral gene delivery vectors of the present invention may be readily constructed from a wide variety of retroviruses, including for example, B, C, and D type retroviruses as well as spumaviruses and lentiviruses. For example, in some cases, a retrovirus, e.g., a lentivirus, is pseudotyped with an envelope protein or other viral protein to facilitate entry into target cells. In some cases, a lentivirus is pseudotyped with vesicular-stomatitis virus g protein. (see RNA Tumor Viruses, Second Edition, Cold Spring Harbor Laboratory, 1985). Such retroviruses may be readily obtained from depositories or collections such as the American Type Culture Collection (“ATCC”; Rockville, Md.), or isolated from known provided herein, and standard recombinant techniques (e.g., Sambrook et al., Molecular Cloning: A Laboratory Manual 2d ed., Cold Spring Harbor Laboratory Press, 1989; Kunkel, PNAS 52: 488, 1985).
In addition, within certain embodiments of the invention, portions of the retroviral gene delivery vectors may be derived from different retroviruses. For example, within one embodiment of the invention, retrovirus LTRs may be derived from a Murine Sarcoma Virus, a tRNA binding site from a Rous Sarcoma Virus, a packaging signal from a Murine Leukemia Virus, and an origin of second strand synthesis from an Avian Leukosis Virus.
Within one aspect of the present invention, retroviral vector constructs are provided comprising a 5′LTR, a tRNA binding site, a packaging signal, one or more heterologous sequences, an origin of second strand DNA synthesis and a 3′LTR, wherein the vector construct lacks gag, pol or env coding sequences.
Other retroviral gene delivery vectors may likewise be utilized within the context of the present invention, and are well known in the art.
Packaging cell lines suitable for use with the above described retroviral vector constructs can be readily prepared according to methods well known in the art, and utilized to create producer cell lines for the production of recombinant vector particles.
Alphavirus delivery vectors: gene delivery vectors suitable for use in the invention can also be based upon alphavirus vectors. For example, the Sindbis virus is the prototype member of the alphavirus genus of the togavirus family. The unsegmented genomic RNA (49S RNA) of Sindbis virus is approximately 11,703 nucleotides in length, contains a 5′cap and a 3′ poly-adenylated tail, and displays positive polarity. Infectious enveloped Sindbis virus is produced by assembly of the viral nucleocapsid proteins onto the viral genomic RNA in the cytoplasm and budding through the cell membrane embedded with viral encoded glycoproteins. Entry of virus into cells is by endocytosis through clatharin coated pits, fusion of the viral membrane with the endosome, release of the nucleocapsid, and uncoating of the viral genome. During viral replication the genomic 49S RNA serves as template for synthesis of the complementary negative strand. This negative strand in turn serves as template for genomic RNA and an internally initiated 26S subgenomic RNA.
The Sindbis viral nonstructural proteins are translated from the genomic RNA while structural proteins are translated from the subgenomic 26S RNA. All viral genes are expressed as a polyprotein and processed into individual proteins by post translational proteolytic cleavage. The packaging sequence resides within the nonstructural coding region, therefore only the genomic 49S RNA is packaged into virions.
Several different Sindbis vector systems may be constructed and utilized within the present invention. Representative examples of such systems include those described within U.S. Pat. Nos. 5,091,309 and 5,217,879, and PCT Publication No. WO 95/07994.
Other viral gene delivery vectors In addition to retroviral vectors and alphavirus vectors, numerous other viral vectors systems may also be utilized as a gene delivery vector. Representative examples of such gene delivery vectors include viruses such as pox viruses, such as canary pox virus or vaccinia virus
Non-viral gene delivery vectors: in addition to the above viral-based vectors, numerous non-viral gene delivery vectors may likewise be utilized within the context of the present invention. Representative examples of such gene delivery vectors include direct delivery of nucleic acid expression vectors, naked DNA (e.g., DNA not contained in a viral vector) (WO 90/11092), polycation condensed DNA linked or unlined to killed adenovirus (Curiel et al., Hum. Gene Ther. 3: 147-154, 1992), DNA ligand linked to a ligand with or without one of the high affinity pairs described above (Wu et al., R of Biol. Chem (264: 16985-16987, 1989), nucleic acid containing liposomes (e.g., WO 95/24929 and WO 95/12387) and certain eukaryotic cells.
Regulatory SequencesIn some embodiments, regulatory sequences or elements are utilized to allow for cell-type or tissue-type specific targeting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof. In related embodiments regulatory elements are used to specifically target retinal neurons, or retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells), or retinal ganglion cells, or photoreceptor cells, or amacrine cells. Examples of regulatory sequences or elements include, but are not limited to promoter, silencer, enhancer, and insulator sequences.
In some embodiments regulatory sequences such as promoters suitable for use in the present invention include constitutive promoters, strong promoters (e.g., CMV promoters), inducible promoters, and tissue-specific or cell-specific promoters (e.g., promoters that preferentially facilitate expression in a limited number of tissues or cell types (e.g., eye tissues, retina, retinal cells, photoreceptor cells, and the like).
Any of a variety of regulatory sequences can be used in the gene delivery vectors of the invention to provide for a suitable level or pattern of expression of the light-sensitive protein of interest. The regulatory sequences are generally derived from eukaryotic regulatory sequences.
In some embodiments non-cell specific regulatory elements are used. In one embodiment, the promoter comprises (from 5′ to 3′) a viral enhancer (a CMV immediate early enhancer), and a beta-actin promoter (a bovine or chicken beta-actin promoter-exon 1-intron 1 element). In a specific embodiment, the promoter comprises (from 5′ to 3′) CMV immediate early enhancer (381 bp)/bovine or chicken beta-actin (CBA) promoter-exon 1-intron 1 (1352 bp) element, which together are termed herein the “CBA promoter” (
In other embodiments, a light-sensitive protein is delivered to a cell type or tissue type of interest using a viral vector such as AAV carrying a selected light-sensitive transgene-encoding DNA regulated by a promoter and/or other regulatory sequences that expresses the product of the DNA in selected retinal cells of a subject. In specific embodiments, expression is targeted to particular types of cells within the retina through the use of a specific promoter nucleotide sequence and/or other regulatory regions such as silencer, enhancer, or insulator sequences which are engineered into the vector. In some embodiments, different regulatory sequences are used to drive expression of different engineered genes in different populations of cells.
In other embodiments retinal bipolar cell-specific regulatory sequences such as promoter, enhancer, silencer, and insulator sequences are used. In specific embodiments the ON bipolar cells are targeted. In other embodiments the OFF bipolar cells are targeted. In other embodiments the rode bipolar cells are targeted. In other embodiments the cone bipolar cells are targeted.
In one embodiment specific expression of a light sensitive proteins in ON bipolar cells is targeted using a light-sensitive protein such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof operatively linked to a GRM6 (metabotropic glutamate receptor 6, mGluR6) regulatory sequence or a fragment thereof. In one embodiment the full length mGluR6 regulatory sequence is utilized.
In another embodiment specific expression of a light sensitive proteins in ON bipolar cells is targeted using a light-sensitive protein such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof operatively linked to a mGluR6 regulatory sequence fragment. In a specific embodiment, the mGluR6 regulatory sequence fragment is the sequence presented in
Many known promoters are too large to fit into the genome of the AAV. Indeed, the original cell-specific regulatory sequence for mGluR6 (Dhingra, 2008) was far too large (approximately 10.5 Kb) to be used in AAV. In a preferred embodiment of the current invention, a mGluR6 regulatory sequence fragment is used, one that is small enough to be used in AAV-mediated delivery. In related embodiments the mGluR6 regulatory sequence fragment is less than about 2000 base pairs, less than about 1000 base pairs, less than about 750 base pairs, less than about 500 base pairs, less than about 250 base pairs, or less than about 100 base pairs in length. In another related embodiment, the mGluR6 regulatory sequence fragment is a variant of the sequence presented in
In another embodiment, specific expression of a light sensitive proteins in ON bipolar cells is targeted using a light-sensitive protein such as ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof operatively linked to a GNA01 (guanine nucleotide binding protein (G protein), alpha activating activity polypeptide O) regulatory sequence. In a related embodiment the regulatory sequence is substantially the same as GNA01 sequence, or is about 60% identical, or is about 70% identical, or is about 80% identical, or is about 90% identical, or is about 95% identical to the GNA01 sequence.
Retinal Bipolar Cells and TargetingAlthough only a fraction of the human visual system, the retina is a complex system that filters, amplifies, and modulates the visual signal before it is sent to the rest of the visual system (Wassle 2004). The vast majority of this processing happens within the inner plexiform layer (IPL) where a system of bipolar and amacrine cells refine the visual signal into its primary components (e.g., motion, contrast, resolution) (Mills 1999; Roska 2001). Some groups are currently targeting ChR2 to the ganglion cell layer, which bypasses the processing power of the IPL and system of amacrine cells (Bi 2006; Greenberg 2007; Tomita 2007). These groups have reported very few behavioral changes.
The majority of retinal cells are either ON-center (increased firing rate as a result of a step increase in contrast within the center of the receptive field) or OFF center type (increased firing rate as a result of a step decrease in contrast in the center of the receptive field), working in a push-pull inhibitory fashion (Wassle 2004). In order to maintain this relationship between the two pathways, these two pathways can be driven independently. ON and OFF channels of information traveling from bipolar to ganglion cells are partially modulated through a network of inhibitory amacrine cells within the inner nuclear layer (Roska 2001). This bipolar-amacrine network produces temporally-distinct parallel channels of information: sustained-activity neurons, for example, maintain activity throughout the light step, whereas transient-activity neurons have activity only at the onset or offset. These distinct patterns of response code for visual information luminance, shape, edges, and motion (Wassle 2004). In some embodiments, cells that are pre-synaptic to the retinal ganglion cells are genetically targeted to maintain the naturalism of these pathways and elicit naturalistic ganglion cell spiking.
In some embodiments, retinal bipolar cells (e.g. ON or OFF retinal bipolar cells; rod and cone bipolar cells) are genetically targeted. Targeting retinal bipolar cells may allow the retina to respond to external light and, more importantly, convey meaningful image information to the brain even in the absence of natural photoreceptors.
Conditions Amenable to TreatmentIn some embodiments, the present invention provides methods of treating a subject suffering from a disease or disorder. The compositions and methods described herein can be utilized to treat central and peripheral nervous system diseases and disorders.
In one aspect, the compositions and methods of this invention are utilized to treat photoreceptor diseases. Photoreceptor diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (ARMD) cause blindness (Congdon 2004) in 15 million people worldwide (Chader 2002), a number that is increasing with the age of the population. There have been attempts to restore basic visual function through gene replacement therapy or cellular transplantation (Acland 2001, Acland 2005, Batten 2005, Pawlyk 2005, Aguirre 2007, MacLaren 2006). However, current approaches are fundamentally limited in scope and extent of potential impact, as they attempt to correct mechanistically distinct genetic pathways on a one-at-a-time basis (Punzo 2007). Photoreceptor diseases are genetically diverse, with over 160 different mutations leading to degeneration (Punzo 2007). There have also been efforts in utilizing electrical stimulation with implanted acute, semi-acute, and long-term retinal prostheses in human subjects (de Balthasar, 2008; Horsager, 2009). They have shown elementary progress but are gene-nonspecific; electrical stimulation offers only gross specificity and indiscriminately drives visual information channels mediated by unique cell types. Activating retinal neurons requires large disc electrodes (at least 20 times the diameter of a retinal ganglion cell), leading to stimulation of broad areas of retina in a nonselective fashion, greatly limiting the achievable visual resolution (Winter 2007). In this aspect, the compositions and methods of this invention consist of introducing a gene encoding a light-sensitive protein (e.g., ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof) to induce light sensitivity in 2nd order neurons (e.g., bipolar cells) delivered using a viral vector such as an AAV8 with a single tyrosine to phenylalanine mutation, under the control of a regulatory element (e.g., GRM6). The activation of these light-sensitive proteins could be controlled by ambient light or through a light-delivery device such as the goggles described in
The methods of the invention can be used to treat (e.g., prior to or after the onset of symptoms) in a susceptible subject or subject diagnosed with a variety of eye diseases. The eye disease may be a results of environmental (e.g., chemical insult, thermal insult, and the like), mechanical insult (e.g., injury due to accident or surgery), or genetic factors. The subject having the condition may have one or both eyes affected, and therapy may be administered according to the invention to the affected eye or to an eye at risk of photoreceptor degeneration due to the presence of such a condition in the subject's other, affected eye.
The present invention provides methods which generally comprise the step of intraocularly administering (e.g., by subretinal injection or by intravitreal injection) a gene delivery vector which directs the expression of a light-sensitive protein to the eye to treat, prevent, or inhibit the onset or progression of an eye disease. As utilized herein, it should be understood that the terms “treated, prevented, or, inhibited” refers to the alteration of a disease onset, course, or progress in a statistically significant manner.
Another condition amenable to treatment according to the invention is Age-related Macular Degeneration (AMD). The macula is a structure near the center of the retina that contains the fovea. This specialized portion of the retina is responsible for the high-resolution vision that permits activities such as reading. The loss of central vision in AMD is devastating. Degenerative changes to the macula (maculopathy) can occur at almost any time in life but are much more prevalent with advancing age. Conventional treatments are short-lived, due to recurrent choroidal neovascularization. AMD has two primary pathologic processes, choroidal neovascularization (CNV) and macular photoreceptor cell death.
Exemplary conditions of particular interest which are amenable to treatment according to the methods of the invention include, but are not necessarily limited to, retinitis pigmentosa (RP), diabetic retinopathy, and glaucoma, including open-angle glaucoma (e.g., primary open-angle glaucoma), angle-closure glaucoma, and secondary glaucomas (e.g., pigmentary glaucoma, pseudoexfoliative glaucoma, and glaucomas resulting from trauma and inflammatory diseases).
Further exemplary conditions amenable to treatment according to the invention include, but are not necessarily limited to, retinal detachment, age-related or other maculopathies, photic retinopathies, surgery-induced retinopathies, toxic retinopathies, retinopathy of prematurity, retinopathies due to trauma or penetrating lesions of the eye, inherited retinal degenerations, surgery-induced retinopathies, toxic retinopathies, retinopathies due to trauma or penetrating lesions of the eye.
Specific exemplary inherited conditions of interest for treatment according to the invention include, but are not necessarily limited to, Bardet-Biedl syndrome (autosomal recessive); Congenital amaurosis (autosomal recessive); Cone or cone-rod dystrophy (autosomal dominant and X-linked forms); Congenital stationary night blindness (autosomal dominant, autosomal recessive and X-linked forms); Macular degeneration (autosomal dominant and autosomal recessive forms); Optic atrophy, autosomal dominant and X-linked forms); Retinitis pigmentosa (autosomal dominant, autosomal recessive and X-linked forms); Syndromic or systemic retinopathy (autosomal dominant, autosomal recessive and X-linked forms); and Usher syndrome (autosomal recessive).
In another aspect, the compositions and methods of this invention are utilized to treat peripheral injury, nociception, or chronic pain. Nociception (pain) for prolonged periods of time can give rise to chronic pain and may arise from injury or disease to visceral, somatic and neural structures in the body. Although the range of pharmacological treatments for neuropathic pain has improved over the past decade, many patients do not get effective analgesia, and even effective medications often produce undesirable side effects. Substance P (SP) is involved in nociception, transmitting information about tissue damage from peripheral receptors to the central nervous system to be converted to the sensation of pain. It has been theorized that it plays a part in fibromyalgia A role of substance P in nociception is suggested by the reduction in response thresholds to noxious stimuli by central administration of NK1 and NK2 agonists. Pain behaviors induced by mechanical, thermal and chemical stimulation of somatic and visceral tissues were reduced in the mutant mice lacking SP/NKA. In one embodiment light-sensitive proteins can silence the activity of over-active neurons (i.e., substance P expressing peripheral neurons) due to peripheral injury or chronic pain using NpHR or eNpHR. NpHR/eNpHR can be genetically targeted to substance P expressing cells using the substance P promoter sequence. In another embodiment light-sensitive proteins enhance the activity of neurons that are inactive due to peripheral injury or chronic pain.
In another aspect, the compositions and methods of this invention are utilized to treat spinal cord injury and/or motor neuron diseases. Spinal cord injury can cause myelopathy or damage to white matter and myelinated fiber tracts that carry sensation and motor signals to and from the brain. It can also damage gray matter in the central part of the spine, causing segmental losses of interneurons and motor neurons. Spinal cord injury can occur from many causes, including but not limited to trauma, tumors, ischemia, abnormal development, neurodevelopmental, neurodegenerative disorders or vascular malformations. In one embodiment light-sensitive proteins activate damaged neural circuits to restore motor or sensory function. In one specific embodiment the elements act to allow control of autonomic and visceral functions. In other embodiments the elements act to allow control of somatic skeletal function. The neural control of storage and voiding of urine is complex and dysfunction can be difficult to treat. One treatment for people with refractory symptoms is continuous electrical nerve stimulation of the sacral nerve roots using implanted electrodes and an implanted pulse generator. However, stimulation of this nerve root can result in a number of different complications or side effects. Being able to directly control the sacral nerve through genetically-targeted tools would be highly beneficial. In one embodiment, both ChR2 and NpHR could be expressed in this nerve to control storage and voiding of the bladder.
In another aspect, the compositions and methods of this invention are utilized to treat Parkinson's disease. Parkinson's disease belongs to a group of conditions called movement disorders. They are characterized by muscle rigidity, tremor, a slowing of physical movement (bradykinesia) and, in extreme cases, a loss of physical movement (akinesia). The primary symptoms are the results of decreased stimulation of the motor cortex by the basal ganglia, normally caused by the insufficient formation and action of dopamine, which is produced in the dopaminergic neurons of the brain. Parkinson's disease is both chronic and progressive. Deep brain stimulation (DBS) is an effective surgical treatment for advanced Parkinson's disease (PD), with significant advantages in morbidity-mortality and quality of life when compared to lesion techniques such as thalamotomy and/or pallidotomy. The procedure is indicated in patients with severe resting tremor, unresponsive to conventional medical treatment or with motor complications. The most commonly reported complications in the intra- and post-surgical period are aborted procedure, misplaced leads, intracranial hemorrhage, seizures and hardware complications, whereas in the long-term period, symptoms may include high level cognitive dysfunction, psychiatric, and subtle language problems. Indeed, this method of therapy would be improved by being able to target specific cell types within a given region to avoid these side effects. In one embodiment light-sensitive proteins specifically activate dopaminergic circuits.
In another specific aspect, the compositions and methods of this invention are utilized to treat epilepsy and seizures. Epilepsy is a neurological disorder that is often characterized by seizures. These seizures are transient signs and/or symptoms due to abnormal, excessive or asynchronous neuronal activity in the brain. Over 30% of people with epilepsy do not have seizure control even with the best available medications. Epilepsy is not a single disorder, but rather as a group of syndromes with vastly divergent symptoms but all involving episodic abnormal electrical activity in the brain. Acute deep brain stimulation (DBS) in various thalamic nuclei and medial temporal lobe structures has recently been shown to be efficacious in small pilot studies. There is little evidence-based information on rational targets and stimulation parameters. Amygdalohippocampal DBS has yielded a significant decrease of seizure counts and interictal EEG abnormalities during long-term follow-up. Data from pilot studies suggest that chronic DBS for epilepsy may be a feasible, effective, and safe procedure. Again, being able to genetically-target activation to specific subsets of cells would improve the quality of the therapy as well as minimize overall side effects. In specific embodiments, the light-sensitive proteins are utilized to alter the asynchronous electrical activity leading to seizures in these deep brain areas.
In another aspect the compositions and methods of this invention are utilized to effect the light-stimulated release of implanted drug or vaccine stores for the prevention, treatment, and amelioration of diseases.
In another aspect the compositions and methods of this invention are utilized to treat neurodegenerative disease selected from but not limited to alcoholism, Alexander's disease, Alper's disease, Alzheimer's disease, Amyotrophic lateral sclerosis, Ataxia telangiectasia, Batten disease (also known as Spielmeyer-Vogt-Sjogren-Batten disease), Bovine spongiform encephalopathy (BSE), chronic pain, Canavan disease, Cockayne syndrome, Corticobasal degeneration, Creutzfeldt-Jakob disease, Huntington's disease, HIV-associated dementia, Kennedy's disease, Krabbe's disease, Lewy body dementia, Machado-Joseph disease (Spinocerebellar ataxia type 3), Multiple sclerosis, Multiple System Atrophy, Narcolepsy, Neuroborreliosis, Parkinson's disease, Pelizaeus-Merzbacher Disease, Pick's disease, Primary lateral sclerosis, Prion diseases, Refsum's disease, Sandhoffs disease, Schilder's disease, Subacute combined degeneration of spinal cord secondary to Pernicious Anaemia, Schizophrenia, Spielmeyer-Vogt-Sjogren-Batten disease (also known as Batten disease), Spinocerebellar ataxia (multiple types with varying characteristics), Spinal muscular atrophy, Steele-Richardson-Olszewski disease, and Tables dorsalis.
In another aspect the compositions and methods of this invention are utilized to treat a neurodevelopmental disease selected from but not limited to attention deficit hyperactivity disorder (ADHD), attention deficit disorder (ADD), schizophrenia, obsessive-compulsive disorder (OCD), mental retardation, autistic spectrum disorders (ASD), cerebral palsy, Fragile-X Syndrome, Downs Syndrome, Rett's Syndrome, Asperger's syndrome, Williams-Beuren Syndrome, childhood disintegrative disorder, articulation disorder, learning disabilities (i.e., reading or arithmetic), dyslexia, expressive language disorder and mixed receptive-expressive language disorder, verbal or performance aptitude. Diseases that can result from aberrant neurodevelopmental processes can also include, but are not limited to bi-polar disorders, anorexia, general depression, seizures, obsessive compulsive disorder (OCD), anxiety, bruixism, Angleman's syndrome, aggression, explosive outburst, self injury, post traumatic stress, conduct disorders, Tourette's disorder, stereotypic movement disorder, mood disorder, sleep apnea, restless legs syndrome, dysomnias, paranoid personality disorder, schizoid personality disorder, schizotypal personality disorder, antisocial personality disorder, borderline personality disorder, histrionic personality disorder, narcissistic personality disorder, avoidant personality disorder, dependent personality disorder, reactive attachment disorder; separation anxiety disorder; oppositional defiant disorder; dyspareunia, pyromania, kleptomania, trichotillomania, gambling, pica, neurotic disorders, alcohol-related disorders, amphetamine-related disorders, cocaine-related disorders, marijuana abuse, opioid-related disorders, phencyclidine abuse, tobacco use disorder, bulimia nervosa, delusional disorder, sexual disorders, phobias, somatization disorder, enuresis, encopresis, disorder of written expression, expressive language disorder, mental retardation, mathematics disorder, transient tic disorder, stuttering, selective mutism, Crohn's disease, ulcerative colitis, bacterial overgrowth syndrome, carbohydrate intolerance, celiac sprue, infection and infestation, intestinal lymphangiectasia, short bowel syndrome, tropical sprue, Whipple's disease, Alzheimer's disease, Parkinson's Disease, ALS, spinal muscular atrophies, and Huntington's Disease. Further examples, discussion, and information on neurodevelopmental disorders can be found, for example, through the Neurodevelopmental Disorders Branch of the National Institute of Mental Health (worldwide website address at nihm.nih.gov/dptr/b2-nd.cfm). Additional information on neurodevelopmental disorders can also be found, for example, in Developmental Disabilities in Infancy and Childhood: Neurodevelopmental Diagnosis and Treatment, Capute and Accardo, eds. 1996, Paul H Brookes Pub Co.; Hagerman, Neurodevelopmental Disorders: Diagnosis and Treatment, 1999, Oxford Univ Press; Handbook of Neurodevelopmental and Genetic Disorders in Children, Goldstein and Reynolds, eds., 1999, Guilford Press; Handbook of Neurodevelopmental and Genetic Disorders in Adults, Reynolds and Goldstein, eds., 2005, Guilford Press; and Neurodevelopmental Disorders, Tager-Flusberg, ed., 1999, MIT Press.
Assessment of TherapyThe effects of therapy according to the invention as described herein can be assessed in a variety of ways, using methods known in the art. For example, the subject's vision can be tested according to conventional methods. Such conventional methods include, but are not necessarily limited to, electroretinogram (ERG), focal ERG, tests for visual fields, tests for visual acuity, ocular coherence tomography (OCT), Fundus photography, Visual Evoked Potentials (VEP) and Pupillometry. In other embodiments, the subject can be assessed behaviorally. In general, the invention provides for maintenance of a subject's vision (e.g., prevention or inhibition of vision loss of further vision loss due to photoreceptor degeneration), slows onset or progression of vision loss, or in some embodiments, provides for improved vision relative to the subject's vision prior to therapy.
Methods of AdministrationThe gene delivery vectors of the present invention can be delivered to the eye through a variety of routes. They may be delivered intraocularly, by topical application to the eye or by intraocular injection into, for example the vitreous (intravitreal injection) or subretinal (subretinal injection) inter-photoreceptor space. Alternatively, they may be delivered locally by insertion or injection into the tissue surrounding the eye. They may be delivered systemically through an oral route or by subcutaneous, intravenous or intramuscular injection. Alternatively, they may be delivered by means of a catheter or by means of an implant, wherein such an implant is made of a porous, non-porous or gelatinous material, including membranes such as silastic membranes or fibers, biodegradable polymers, or proteinaceous material. The gene delivery vector can be administered prior to the onset of the condition, to prevent its occurrence, for example, during surgery on the eye, or immediately after the onset of the pathological condition or during the occurrence of an acute or protracted condition.
In another embodiment the inner limiting membrane (ILM) is broken down to effect delivery. The ILM is the boundary between the retina and the vitreous body, formed by astrocytes and the end feet of Muller cells. In both nonhuman primates and humans, the ILM is thick and provides a substantial barrier to the retina. Indeed, using intravitreal injections, most viral particles are incapable of transducing retinal cells. In one embodiment, to improve transduction efficiency, an ILM peel is conducted comprising carrying out a surgical procedure that comprises peeling off a small part of the ILM. In another embodiment, to improve transduction efficiency, the ILM barrier can be partially or wholly broken down comprising using enzymatic techniques and one or more enzymes.
In one embodiment the ILM is maintained to limit the therapeutic effect of the light-sensitive protein to the macula. In another embodiment the ILM peel procedure and/or the ILM enzymatic digestion procedure, both described herein is used to achieve a broader distribution of the light-sensitive protein.
The gene delivery vector can be modified to enhance penetration of the blood-retinal barrier. Such modifications may include increasing the lipophilicity of the pharmaceutical formulation in which the gene delivery vector is provided.
The gene delivery vector can be delivered alone or in combination, and may be delivered along with a pharmaceutically acceptable vehicle. Ideally, such a vehicle would enhance the stability and/or delivery properties. The invention also provides for pharmaceutical compositions containing the active factor or fragment or derivative thereof, which can be administered using a suitable vehicle such as liposomes, microparticles or microcapsules. In various embodiments of the invention, it may be useful to use such compositions to achieve sustained release of the active component.
The amount of gene delivery vector (e.g., the number of viral particles), and the amount of light-sensitive protein expressed, effective in the treatment of a particular disorder or condition may depend of the nature of the disorder or condition and a variety of patient-specific factors, and can be determined by standard clinical techniques.
In one embodiment, the gene delivery vectors are administered to the eye, intraocularly to a variety of locations within the eye depending on the type of disease to be treated, prevented, or, inhibited, and the extent of disease. Examples of suitable locations include the retina (e.g., for retinal diseases), the vitreous, or other locations in or adjacent the retina or in or adjacent the eye.
The human retina is organized in a fairly exact mosaic. In the fovea, the mosaic is a hexagonal packing of cones. Outside the fovea, the rods break up the close hexagonal packing of the cones but still allow an organized architecture with cones rather evenly spaced surrounded by rings of rods. Thus in terms of densities of the different photoreceptor populations in the human retina, it is clear that the cone density is highest in the foveal pit and falls rapidly outside the fovea to a fairly even density into the peripheral retina (see Osterberg, G. (1935) Topography of the layer of rods and cones in the human retina. Acta Ophthal. (suppl.) 6, 1-103; see also Curcio, C. A., Sloan, K. R., Packer, O., Hendrickson, A. E. and Kalina, R. E. (1987) Distribution of cones in human and monkey retina: individual variability and radial asymmetry. Science 236, 579-582).
Access to desired portions of the retina, or to other parts of the eye may be readily accomplished by one of skill in the art (see, generally Medical and Surgical Retina: Advances, Controversies, and Management, Hilel Lewis, Stephen J. Ryan, Eds., medical-“illustrator, Timothy C. Hengst. St. Louis: Mosby, c1994. xix, 534; see also Retina, Stephen J. Ryan, editor in chief, 2nd ed., St. Louis, Mo.: Mosby, c1994. 3 v. (xxix, 2559).
In one embodiment, the amount of the specific viral vector applied to the retina is uniformly quite small as the eye is a relatively contained structure and the agent is injected directly into it. The amount of vector that needs to be injected is determined by the intraocular location of the chosen cells targeted for treatment. The cell type to be transduced may be determined by the particular disease entity that is to be treated.
For example, a single 20-microliter volume (e.g., containing about 1013 physical particle titer/ml rAAV) may be used in a subretinal injection to treat the macula and fovea of a human eye. A larger injection of 50 to 100 microliters may be used to deliver the rAAV to a substantial fraction of the retinal area, perhaps to the entire retina depending upon the extent of lateral spread of the particles.
A 100 microliter injection may provide several million active rAAV particles into the subretinal space. This calculation is based upon a titer of 1013 physical particles per milliliter. Of this titer, it is estimated that 1/1000 to 1/10,000 of the AAV particles are infectious. The retinal anatomy constrains the injection volume possible in the subretinal space (SRS). Assuming an injection maximum of 100 microliters, this could provide an infectious titer of 105 to 109 rAAV in the SRS. This would have the potential of infecting all of the approximately 150×106 photoreceptors in the entire human retina with a single injection.
Smaller injection volumes focally applied to the fovea or macula may adequately transfect the entire region affected by the disease in the case of macular degeneration or other regional retinopathies.
Depending on the application at least 103, 104, 105, 106, 107, 108, 109, 1010, 1011, 1012, 1013, 1014, or more particles can be delivered into the tissue of interest.
Gene delivery vectors can alternately be delivered to the eye by intraocular injection into the vitreous, e.g., to treat glaucomatous loss of retinal ganglion cells through apoptosis. In the treatment of glaucoma, the primary target cells to be transduced are the retinal ganglion cells, the retinal cells primarily affected. In such an embodiment, the injection volume of the gene delivery vector could be substantially larger, as the volume is not constrained by the anatomy of the subretinal space. Acceptable dosages in this instance can range from about 25 microliters to 1000 microliters.
Pharmaceutical CompositionsGene delivery vectors can be prepared as a pharmaceutically acceptable composition suitable for administration. In general, such pharmaceutical compositions comprise an amount of a gene delivery vector suitable for delivery of light-sensitive protein-encoding polynucleotide to a cell of the eye for expression of a therapeutically effective amount of the light-sensitive protein, combined with a pharmaceutically acceptable carrier or excipient. Preferably, the pharmaceutically acceptable carrier is suitable for intraocular administration. Exemplary pharmaceutically acceptable carriers include, but are not necessarily limited to, saline or a buffered saline solution (e.g., phosphate-buffered saline).
Various pharmaceutically acceptable excipients are well known in the art. As used herein, “pharmaceutically acceptable excipient” includes any material which, when combined with an active ingredient of a composition, allows the ingredient to retain biological activity, preferably without causing disruptive reactions with the subject's immune system or adversely affecting the tissues surrounding the site of administration (e.g., within the eye).
Exemplary pharmaceutically carriers include sterile aqueous of non-aqueous solutions, suspensions, and emulsions. Examples include, but are not limited to, any of the standard pharmaceutical excipients such as a saline, buffered saline (e.g., phosphate buffered saline), water, emulsions such as oil/water emulsion, and various types of wetting agents.
Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, hyaluronic acid, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate.
Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media. Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's or fixed oils. Intravenous vehicles can include fluid and nutrient replenishers, electrolyte replenishers (such as those based on Ringer's dextrose), and the like.
A composition of gene delivery vector of the invention may also be lyophilized using means well known in the art, for subsequent reconstitution and use according to the invention. Where the vector is to be delivered without being encapsulated in a viral particle (e.g., as “naked” polynucleotide), formulations for liposomal delivery, and formulations comprising microencapsulated polynucleotides, may also be of interest.
Compositions comprising excipients are formulated by well known conventional methods (see, for example, Remington's Pharmaceutical Sciences, Chapter 43, 14th Ed., Mack Publishing Col, Easton Pa. 18042, USA).
In general, the pharmaceutical compositions can be prepared in various forms, preferably a form compatible with intraocular administration. Stabilizing agents, wetting and emulsifying agents, salts for varying the osmotic pressure or buffers for securing an adequate pH value may also optionally be present in the pharmaceutical composition.
The amount of gene delivery vector in the pharmaceutical formulations can vary widely, i.e., from less than about 0.1%, usually at or at least about 2% to as much as 20% to 50% or more by weight, and may be selected primarily by fluid volumes, viscosities, etc., in accordance with the particular mode of administration selected.
The pharmaceutical composition can comprise other agents suitable for administration, which agents may have similar to additional pharmacological activities to the light-sensitive protein to be delivered (e.g., ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof).
KitsThe invention also provides kits comprising various materials for carrying out the methods of the invention. In one embodiment, the kit comprises a vector encoding a light-sensitive protein polypeptide (e.g. ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof), which vector is adapted for delivery to a subject, particularly an eye of the subject, and adapted to provide for expression of the light-sensitive polypeptide in a cell of an eye, particularly a mammalian cell. The kit can comprise the vector in a sterile vial, which may be labeled for use. The vector can be provided in a pharmaceutical composition. In one embodiment, the vector is packaged in a virus. The kit can further comprise a needle and/or syringe suitable for use with the vial or, alternatively, containing the vector, which needle and/or syringe are preferably sterile. In another embodiment, the kit comprises a catheter suitable for delivery of a vector to the eye, which catheter may be optionally attached to a syringe for delivery of the vector. The kits can further comprise instructions for use, e.g., instructions regarding route of administration, dose, dosage regimen, site of administration, and the like.
DevicesThe data in
In one embodiment, an internal light-generating device is implanted.
In another embodiment, a protective optic, or a contact lens-type barrier is implanted either in conjunction with or independent of the device. In a specific embodiment such an optic or contact lens protects photoreceptors from light stimulation. In a specific embodiment the lens comprises tinting over photoreceptors, and clear over light-sensitive protein transduction area.
In some embodiments a head-mounted, external device or eyewear is utilized. In certain embodiments where the light-sensitive element is not triggered to the extent desired by natural or ambient light, an additional light production or generation source such as a LED array/laser system is provided. In certain embodiments the external eyewear can additionally include a camera and an image processing unit for the filtering, enhancement, processing, and resolution of the presented images.
In one embodiment, an exemplary camera system would comprise at least three main components: 1) A small camera built into the glasses, 2) an imaging processing unit, and 3) a light delivery system that includes either or both LEDs or a laser system. The camera could either be a single lens camera or a dual camera system that could potentially provide binocular imaging and depth information. The camera could capture either visual light or infrared light. The camera could either be adaptive to various lighting conditions or could be fixed. The image processing unit (IPU) could provide any number of signal transformations including amplification, increased or decreased contrast, structure from motion, edge enhancement, or temporal filtering (i.e., integration). Additionally, saliency algorithms could be employed such that only certain objects within the field of view are enhanced (e.g., moving cars, doorways) and less important objects (e.g., clouds), are filtered out. The LED and/or laser lighting array system could contain a high-density LED array or a scanning laser system that consists of either one (1) or more lasers. The position of the lights could be either fixed or could move. For example, the orientation of the lights relative to the eye could move as a function of eye movements, using an eye movement tracking device as an input. This is depicted in
In another related exemplary embodiment, an image intensifying device, such as those provided by Telesensory (http://www.telesensory.com), may be combined with a retinal scanning device (RSD) as developed by Microvision (http://www.microvision.com/milprod.html), to provide a head-worn apparatus capable of delivering a bright, intensified image directly to the retina of a patient with impaired vision. Briefly, a RSD projects images onto the retina such that an individual can view a large, full-motion image without the need for additional screens or monitors. Thus, by projecting an intensified image directly onto the retina of an individual with impaired vision, it may be possible to improve vision in those considered to be blind or near-blind.
While some embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention.
EXAMPLES Example 1 Injection MethodsAll procedures in animals were handled according to the statement for the use of animals in Ophthalmic and Vision Research of the Association of Research in Vision and Ophthalmology and the guidelines of the Institutional Animal Care and Use Committee at the University of Florida.
For intravitreal injections, mice were anesthetized with ketamine (72 mg/kg)/xylazine (4 mg/kg) by intraperitoneal injection. Following anesthetization, a Hamilton syringe fitted with a 33-gauge beveled needle was used. The needle was passed through the sclera, at the equator, next to the limbus, into the vitreous cavity. Injection occurred with direct observation of the needle in the center of the vitreous cavity. The total volume delivered was 1.5 containing different concentrations of the AAV vectors tested.
For subretinal injections, one hour before the anesthesia, eyes of mice were dilated with eye drops of 1% atropine, followed by topical administration of 2.5% phenylephrine. Mice were then anesthetized with ketamine (72 mg/kg)/xylazine (4 mg/kg) by intraperitoneal injection An aperture within the pupil was made through the cornea with a 30½-gauge disposable needle and a 33-gauge unbeveled blunt needle in a Hamilton syringe was introduced through the corneal opening into the subretinal space and 1.5 μl of AAV was delivered.
Typical titers of the AAV vectors were between 1.3×1012 and 3.0×1013.
Example 2 Screening for AAV Serotypes 1, 2, 5, 7, 8, and 9 for Transduction of Retinal Bipolar CellsScreening of known and characterized viral vectors for optimal transduction of retina bipolar cells was carried out. AAV serotypes 1, 2, 5, 7, 8 and 9 carrying green fluorescent protein (GFP) were individually subretinally injected in 4 week old rd1 mice. Rd1 homozygous mice carry a rd1 mutation and rod photoreceptor degeneration in these mice begins around postnatal day (P)10 and is almost completed by P21. GFP was placed under control of the strong, non-cell type specific promoter CBA (fusion of the CMV immediate early enhancer and the bovine β-actin promoter plus intron1-exon1 junction). 1 month later, mice were tested for expression of GFP. Double labeling with the PKCα antibody of mice injected with AAV7 demonstrated that the transduced cells were most likely residual (no outer segment) photoreceptors rather than bipolar cells. Subretinal injections with AAV7 were then performed in 8 week old mice, where there is less of a chance of residual photoreceptors. It was found that AAV7 was highly effective at transducing retinal bipolar cells, leading to GFP expression in at least 75% of all bipolar cells after a single injection (
As depicted in
The images in
mGluR6 is a G-protein coupled metabotropic glutamate receptor that is, in the retina, specifically expressed in ON bipolar cells (Tian 2006). The adeno-associated virus, serotype 7 (AAV7), an mGluR6 regulatory sequence fragment gene sequence (presented in
Using a tyrosine-mutated version of AAV8 (at the 733 location), under the control of bipolar cell specific promoter GRM6, in the self-complementary configuration, it was possible to restore visual behavioral efficacy in rd1 mice, as depicted in
Using a tyrosine-mutated version of AAV8 (at the 446 location), under the control of the non-cell specific promoter CBA (fusion of the CMV immediate early enhancer and the bovine β-actin promoter plus intron1-exon1 junction, and ChR2), in the self-complementary configuration, most or all bipolar cells can be targeted and visual function is restored as depicted in
Using the AAV5, non-cell type specific promoter CBA (fusion of the CMV immediate early enhancer and the bovine β-actin promoter plus intron1-exon1 junction, and ChR2, in the self-complementary configuration, all bipolar cells can be targeted and visual function and behavior is restored (
These mice were then trained on a water maze task
The animals' performance on the task was then evaluated at different light levels.
Claims
1. A recombinant nucleic acid comprising a nucleic acid encoding a light-sensitive protein operatively linked to a metabotropic glutamate receptor 6 (mGluR6) regulatory sequence or fragment thereof.
2. The nucleic acid of claim 1 wherein the light-sensitive protein is selected from the group consisting of ChR1, ChR2, VChR1, ChR2 C128A, ChR2 C128S, ChR2 C128T, ChR1-ChR2 hybrids/chimeras, ChD, ChEF, ChF, ChIEF, NpHR, eNpHR, melanopsin, and variants thereof.
3. The nucleic acid of claim 1 wherein the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70% identical to ChR2.
4. The nucleic acid of claim 1 wherein the mGluR6 regulatory sequence fragment comprises less than about 1000 base pairs.
5. The nucleic acid of claim 1 wherein the mGluR6 regulatory sequence or fragment thereof is an mGluR6 promoter or enhancer.
6. The nucleic acid of claim 1 further comprising a green fluorescent protein.
7. The nucleic acid of claim 1 wherein the nucleic acid is encapsidated within a recombinant adeno-associated virus (AAV).
8. The nucleic acid of claim 7 wherein the recombinant adeno-associated virus is of a serotype selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof.
9. The nucleic acid of claim 7 wherein the recombinant adeno-associated virus is of a serotype selected from the group consisting of AAV2, AAV5, AAV7, AAV8, and hybrids thereof.
10. The nucleic acid of claim 1 wherein the nucleic acid is encapsidated within a recombinant virus selected from the group consisting of recombinant adeno-associated virus (AAV), recombinant retrovirus, recombinant lentivirus, and recombinant poxvirus.
11. A vector comprising a nucleic acid encoding a light-sensitive protein, said nucleic acid operatively linked to a metabotropic glutamate receptor 6 (mGluR6) regulatory sequence or fragment thereof.
12-22. (canceled)
23. A method of treating a subject suffering from a disease or disorder of the eye comprising introducing into an affected eye a recombinant adeno-associated virus (AAV) comprising a light-sensitive protein operatively linked to a metabotropic glutamate receptor 6 regulatory sequence (mGluR6 regulatory sequence) or fragment thereof.
24. The method of claim 23 wherein the disease or disorder of the eye is caused by photoreceptor cell degeneration.
25. (canceled)
26. The method of claim 23 wherein the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70% identical to ChR2.
27. The method of claim 23 wherein the mGluR6 regulatory sequence fragment is less than about 1000 base pairs.
28. The method of claim 27 wherein the mGluR6 regulatory sequence fragment is represented by the sequence in FIG. 6.
29. The method of claim 23 wherein the AAV is of a serotype selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof.
30. The method of claim 29 wherein the AAV comprises a mutated capsid protein.
31. (canceled)
32. The method of claim 31 wherein the mutated tyrosine residue is selected from the group consisting of Y252F, Y272F, Y444F, Y500F, Y700F, Y704F, Y730F, Y275F, Y281F, Y508F, Y576F, Y612G, Y673F and Y720F.
33. (canceled)
34. The method of claim 23 wherein the AAV is introduced using intravitreal injection, subretinal injection and/or ILM peel.
35. The method of claim 23 wherein the AAV is introduced into a retinal bipolar cell.
36. The method of claim 23 wherein the method further comprises using a light-generating device external to the eye.
37. A method of expressing an exogenous nucleic acid in a retinal bipolar cell comprising introducing into a retina a vector comprising the exogenous nucleic operatively linked to a retinal bipolar cell-specific regulatory sequence wherein the method results in at least about a 10% transduction efficiency.
38. (canceled)
39. (canceled)
40. The method of claim 37 wherein the exogenous nucleic acid comprises a light-sensitive protein.
41. (canceled)
42. The nucleic acid of claim 40 wherein the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70% identical to ChR2.
43. The method of claim 37 wherein the regulatory sequence comprises a metabotropic glutamate receptor 6 regulatory sequence (mGluR6) or a fragment thereof.
44. The method of claim 43 wherein the mGluR6 regulatory sequence fragment is less than about 1000 base pairs.
45. (canceled)
46. The method of claim 36 wherein the exogenous nucleic acid is introduced using a recombinant adeno-associated viral vector (AAV).
47. (canceled)
48. The method of claim 47 wherein the capsid protein comprises a mutated tyrosine residue.
49. The method of claim 48 wherein the mutated tyrosine residue is selected from the group consisting of Y252F, Y272F, Y444F, Y500F, Y700F, Y704F, Y730F, Y275F, Y281F, Y508F, Y576F, Y612G, Y673F and Y720F.
50. (canceled)
51. The method of claim 46 wherein the exogenous nucleic acid is introduced using intravitreal injection, subretinal injection, and/or ILM peel.
52. The method of claim 46 wherein the AAV is of a serotype is selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof.
53. A method of introducing an exogenous nucleic acid into the nucleus of a retinal cell comprising introducing a vector comprising an exogenous nucleic acid operatively linked to a retinal cell-specific regulatory sequence into a retinal cell, wherein the vector is specifically designed to avoid ubiquitin-mediated protein degradation.
54. (canceled)
55. The method of claim 53 wherein the exogenous nucleic acid comprises a light-sensitive protein.
56. (canceled)
57. The nucleic acid of claim 55 wherein the light-sensitive protein is ChR2 or a light-sensitive protein that is at least about 70% identical to ChR2.
58. The method of claim 53 wherein the retinal cell is a retinal bipolar cell.
59. The method of claim 58 wherein the regulatory sequence comprises a metabotropic glutamate receptor 6 regulatory sequence (mGluR6) or fragment thereof.
60. The method of claim 59 wherein the mGluR6 fragment is less than 1000 base pairs.
61. The method of claim 59 wherein the mGluR6 regulatory sequence fragment is represented by the sequence in FIG. 6.
62. (canceled)
63. The method of claim 53 the vector is a recombinant adeno-associated viral vector (AAV).
64. The method of claim 63 wherein the AAV is of a serotype selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, and hybrids thereof.
65. The method of claim 63 wherein the AAV comprises a mutated capsid protein.
66. The method of claim 65 wherein the capsid protein comprises a mutated tyrosine residue.
67. The method of claim 66 wherein the mutated tyrosine residue is selected from the group consisting of Y252F, Y272F, Y444F, Y500F, Y700F, Y704F, Y730F, Y275F, Y281F, Y508F, Y576F, Y612G, Y673F and Y720F.
68. (canceled)
69. The method of claim 53 wherein the vector is introduced using intravitreal injection, subretinal injection, and/or ILM peel.
70. A method of transducing a retinal bipolar cell comprising introducing into a retina a vector comprising an exogenous nucleic acid operatively linked to a regulatory sequence.
71-83. (canceled)
Type: Application
Filed: May 20, 2009
Publication Date: Apr 19, 2012
Inventors: Alan Horsager (Los Angeles, CA), William Hauswirth (Gainesville, FL), Jianwen Liu (Gainesville, FL), Benjamin Matteo (San Francisco, CA), Edward S. Boyden, III (Chestnut Hill, MA)
Application Number: 12/993,092
International Classification: A61K 48/00 (20060101); C12N 15/867 (20060101); A61M 37/00 (20060101); C12N 15/86 (20060101); A61P 27/02 (20060101); C12N 15/85 (20060101); C12N 15/863 (20060101);
