METHODS OF PREVENTING, TREATING AND DIAGNOSING DISORDERS OF PROTEIN AGGREGATION
Disclosed are methods of preventing, treating, or diagnosing in a subject a disorder in protein folding or aggregation, or amyloid formation, deposition, accumulation, or persistence consisting of administering to said subject a pharmaceutically effective amount of inositol stereoisomers, enantiomers or derivatives thereof.
This application claims the priority of U.S. Provisional Application Ser. Nos. 60/451,363, 60/520,958 and 60/523,534, filed Feb. 27, 2003, Nov. 17, 2003 and Nov. 19, 2003, respectively.
FIELD OF THE INVENTIONThe invention relates to methods for treating Alzheimer's Disease and other amyloidoses; more particularly, it relates to methods for inhibiting and reducing amyloid fibril formation in therapeutic intervention in Alzheimer's disease and other amyloidoses.
DESCRIPTION OF THE RELATED ARTAlzheimer's disease is characterized neuropathologically by amyloid deposits, neurofibrillary tangles, and selective neuronal loss. The major component of the amyloid deposits is amyloid-β(Aβ), a 39-43 residue peptide. Soluble forms of Aβ generated from cleavage of amyloid precursor protein are normal products of metabolism. The importance of residues 1-42 (Aβ42) in Alzheimer's disease was highlighted in the discovery that mutations in codon 717 of the amyloid precursor protein gene, presenilin 1 and presenilin 2 genes result in an increased production of Aβ42 over Aβ1-40. These results in conjunction with the presence of Aβ42 in both mature plaques and diffuse amyloid lead to the hypothesis that this more amyloidogenic species may be the critical element in plaque formation. This hypothesis was supported by the fact that Aβ42 deposition precedes that of Aβ40 in Down's syndrome in PS1 mutations and in hereditary cerebral hemorrhage with amyloidosis.
Many in vitro studies have demonstrated that Aβ can be neurotoxic or enhance the susceptibility of neurons to excitotoxic, metabolic, or oxidative insults. Initially it was thought that only the fibrillar form of A was toxic to neurons but more thorough characterization of Aβ structures demonstrated that dimers and small aggregates of Aβ are also neurotoxic. These data suggested that prevention of Aβ oligomerization would be a likely strategy to prevent AD-related neurodegeneration. Several studies have demonstrated that in vitro Aβ-induced neurotoxicity can be ablated by compounds that can increase neuronal resistance by targeting cellular pathways involved in apoptosis, block downstream pathways after Aβ induction of destructive routes, or block Aβ oligomerization and ultimately fibril formation. The site at which Aβ acts to induce neurotoxicity has yet to be elucidated but its toxic effects have been blocked by a variety of disparate agents.
Docking of Aβ-fibrils to neuronal and glial cell membranes may be an early and intervenable step during the progression of AD. Formation of amyloid plaques, as well as neurotoxicity and inflammation may be direct or indirect consequences of the interaction of A with molecules containing sugar moieties. Previous studies have demonstrated that Aβ interaction with glycosaminoglycans results in aggregation of Aβ possibly adding to their insolubility and plaque persistence. Glycosaminoglycans have also been implicated in neuronal toxicity and microglial activation. Alternatively, interaction with glycolipids such as gangliosides results in the stabilization and prevention of Ab fibril formation, as well as, the site of Aβ production. The family of phosphatidylinositols, on the other hand, results in acceleration of fibril formation. The headgroup of phosphatidylinositol is myo-inositol, a naturally occurring simple sugar involved in lipid biosynthesis, signal transduction, and osmolarity control.
It is also noteworthy that a variety of other human diseases also demonstrate amyloid deposition and usually involve systemic organs (i.e. organs or tissues lying outside the central nervous system), with the amyloid accumulation leading to organ dysfunction or failure. In Alzheimer's disease and “systemic” amyloid diseases, there is currently no cure or effective treatment, and the patient usually dies within 3 to 10 years from disease onset.
U.S. Pat. No. 4,847,082 discloses the use of phytic acid, a phytate salt, an isomer or hydrolysate of phytic acid for the treatment of Alzheimer's disease. It also discloses that isomers of phytic acid or phytate salt comprise the hexakisphosphate myo-inositol, hexakisphosphate scyllo-inositol, hexakisphosphate D-chiro-inositol, hexakisphosphate L-chiro-inositol, hexakisphosphate neo-inositol and hexakisphosphate muco-inositol conformations. Phytic acid is inositol-hexakisphosphate (IP6).
U.S. Pat. No. 5,112,814 discloses the use of phytic acid and isomers thereof for the treatment of Parkinson's disease. As is the case with U.S. Pat. No. 4,847,082, the phytic acid isomers disclosed in this patent retain the six phosphate groups on the six-carbon inositol sugar.
It is noteworthy that in subsequent publications, the ability of inositol-monophosphate, inositol-1,4-bisphosphate and inositol-1,4,5-triphosphate to inhibit amyloid-beta peptide fibrillogenesis were investigated and found not to be effective (J. Mol. Biol. 278:183-194, 1998).
Barak et al. disclose the use of inositol for the treatment of Alzheimer's Disease (AD). (Prog Neuro-psychoparmacol & Biol Psychiat. 20:729-735, 2000). However, this reference does not disclose the use of inositol isomers. Patients treated with inositol did not show any significant differences in overall cognitive function scores (CAMCOG index) between inositol and placebo (dextrose) in AD patients while two specific subscales of the CAMCOG index did show significant improvement (orientation and language).
Levine J. reviews the above Barak et al. paper and specifically states that inositol treatment is not beneficial in AD or ECT-induced cognitive impairment (Eur Neuropsychoparm. 1997; 7,147-155, 1997).
Colodny L, et al. suggests further studies for the usefulness of inositol in Alzheimer's disease by referring to the above Barak et al. paper and therefore does not disclose or suggest such use for inositol isomers (Altern Med Rev 3(6):432-47, 1998).
McLaurin et al. disclosed that myo-inositol stabilizes a small micelle of Aβ42 (J. Mol. Biol. 278, 183-194, 1998). In addition, McLaurin et al. disclose that epi- and scyllo- but not chiro-inositol were able to induce a structural transition from random to β-structure in Aβ42 (J Biol. Chem. Jun. 16; 275(24):18495-502, 2000; and J Struct Biol 130:259-270, 2000). Alternatively, none of the stereoisomers were able to induce a structural transition in Aβ40. Electron microscopy showed that inositol stabilizes small aggregates of Aβ42. These references also disclose that inositol-Aβ interactions result in a complex that is non-toxic to nerve growth factor-differentiated PC-12 cells and primary human neuronal cultures.
Much work in Alzheimer's disease has been accomplished, but little is conventionally known about compounds or agents for therapeutic regimes to arrest or reverse amyloid formation, deposition, accumulation and/or persistence that occurs in Alzheimer's disease and other amyloidoses.
New compounds or agents for therapeutic regimes to arrest or reverse amyloid formation, deposition, accumulation and/or persistence that occurs in Alzheimer's disease and other amyloidoses are therefore desperately needed.
SUMMARY OF THE INVENTIONThe present invention provides a method of treating or preventing in a subject a condition of the central or peripheral nervous system or systemic organ associated with a disorder in protein folding or aggregation, or amyloid formation, deposition, accumulation, or persistence comprising administering to said subject a pharmaceutically effective amount of compound selected having the following structure:
wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of:
-
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10 acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR9R9 and SR11,
providing that the compound is not myo-inositol.
The present invention also provides a method of preventing abnormal protein folding, abnormal protein aggregation, amyloid formation, deposition, accumulation, or persistence, or amyloid lipid interactions in a subject comprising administering to said subject a pharmaceutically effective amount of a compound having the following structure:
wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of:
-
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10 acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11,
providing that the compound is not myo-inositol.
The present invention further provides a method of causing the dissociation of abnormally aggregated proteins and/or dissolving or disrupting pre-formed or pre-deposited amyloid fibril or amyloid in a subject comprising administering to said subject a pharmaceutically effective amount of a compound having the following structure:
wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of:
-
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11,
providing that the compound is not myo-inositol.
The present invention also provides a method of diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in a subject comprising: (a) administering to said subject a radioactive compound or compound tagged with a substance that emits a detectable signal in a quantity sufficient and under conditions to allow for the binding of said compound to the abnormally folded or aggregated protein and/or fibrils or amyloid, if present; and (b) detecting the radioactivity or the signal from the compound bound to the abnormally folded or aggregated protein and/or fibrils or amyloid, thus diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in said subject, wherein said compound has the following structure:
wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of:
-
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10 acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11,
providing that the compound is not myo-inositol.
The present invention further provides a method of diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in a subject comprising: (a) collecting a sample from said subject; (b) contacting said sample with a radioactive compound or compound tagged with a substance that emits a detectable signal under conditions to allow the binding of said compound to the abnormally folded or aggregated protein and/or amyloid fibril or amyloid if present; and (c) detecting the radioactivity or the signal from the compound bound to the abnormally folded or aggregated protein and/or fibrils or amyloid, thus diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in said subject, wherein said compound has the following structure:
wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of;
-
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10 acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11,
providing that the compound is not myo-inositol.
The present invention discloses novel, unpredictable and unexpected properties of certain inositol stereoisomers in relation to the treatment of amyloid-related disorders such as Alzheimer's Disease.
It has been surprisingly discovered that certain stereoisomers of inositol and related compounds block Aβ-induced progressive cognitive decline and cerebral amyloid plaque pathology, and improve survival when given to a transgenic mouse model of human Alzheimer Disease during the nascent phase of Aβ deposition.
As disclosed above, previous data suggested that some, but not all, inositol stereoisomers might have an effect on amyloid aggregation in cultured neuronal cells in vitro (McLaurin et al., J. Biol. Chem. 275(24): 18495-18502 (2000)). Those observations did not provide any method to predict which, if any, of the studied stereoisomers (myo-, epi-, scyllo- and chiro-inositols) would have such effects, nor whether any other stereoisomers would have such effects. Also, those studies could not predict if any inositol stereoisomers would have effects on amyloid deposition, cognitive defects or lifespan in vivo. The present invention describes the unpredictable results that only certain inositol stereoisomers, in particular scyllo- and allo-inositols reduce amyloid plaque burden, improve cognition and increase lifespan in animal models of amyloid-related disorders, whereas others studied did not have such effects.
Previous studies also suggested only that certain inositol stereoisomers (e.g. epi- and scyllo-inositols) might inhibit de novo amyloid aggregation in vitro. The present invention describes the unexpected results that scyllo-inositol inhibits already established cerebral amyloid deposition, and does so in the living brain. This is not implied by the previously published in vitro data which considered only certain neuronal cell types in culture, not the complex tissues of the living brain, and only suggested that inositols might inhibit de novo aggregation, thereby having no relevance to established disease.
Previous in vitro data also suggested that epi- and scyllo-inositol administration affects amyloid Aβ40 levels as well as Aβ42 levels. The in vivo dosing study of the present invention revealed the unpredictable result that administration of allo- or scyllo-inositol specifically reduced Aβ42 levels, whereas insoluble Aβ42 and either soluble or insoluble Aβ40 levels were unaffected.
The observation of the present invention showing changes in glial activity and inflammation is novel and surprising, and could not have been predicted by the in vitro data previously published.
The observation of the present invention demonstrating that scyllo-inositol improves lifespan in transgenic model animals is also novel and surprising, since no drug for Alzheimer's Disease has previously been shown to increase survival and extend lifespan in vivo.
Preferably, the compounds of the present invention are 1,2,3,4,5,6-cyclohexanehexyls, more preferably selected from the group of cis-, epi-, allo-, muco-, neo-, scyllo-, D-chiro- and L-chiro-inositols.
Also preferably, these compounds are 1,2,3,4,5-cyclohexanepentols (quercitols), more preferably selected from the group of epi-, vibo-, scyllo-, allo-, talo-, gala-, cis-, muco-, neo-, proto-quercitols and enantiomers thereof.
Also preferably, these compounds are selected from the group of a cyclohexanetetrol, a cyclohexanetriol, stereoisomer of cyclohexanetetrol, stereoisimer of cyclohexanetriol, enantiomer of cyclohexanetetrol, and enantiomer of cyclohexanetriol.
These compounds may also be compound is pentahydxycyclohexanones or stereoisomers or enantiomers thereof.
Yet again preferably, these compounds are inosose compounds selected from the group of scyllo-inosose, L-chiro-inosose-1 and L-epi-inosose.
Also preferably, these compounds are trihydroxyxcyclohexanones, or stereoisomers or enantiomers thereof. More preferably, (−)-1-deoxy-scyllo-inosose.
Also preferably, these compounds are pentahydxycyclohexanones (inosose), or stereoisomers or enantiomers thereof, more preferably selected from the group of scyllo-inosose, L-chiro-inosose-1 and L-epi-inosose.
Optionally, these compounds are trihydroxyxcyclohexanones or stereoisomers or enantiomers thereof such as (−)-1-deoxy-scyllo-inosose.
Also preferably, these compounds are O-monomethyl-cyclohexanehexyls or stereoisomers or enantiomers thereof; more preferably selected from the group of D-pinitol, L-quebrachitol and D-bornesitol.
Again, these compounds may be selected from the group of monoaminocyclohexanepentols (inosamines), diaminocyclohexanetetrols (inosadiamines), diaminocyclohexanetriols, stereoisomers thereof; and enantiomers thereof, and pharmaceutically acceptable salts thereof such as L-neo-inosamine, D,L-epi-inosamine-2, streptamine and deoxystreptamine.
Yet again preferably, these compounds are monomercapto-cyclohexanepentols or stereoisomers or enantiomers thereof, more preferably 1L-1-deoxy-1-mercapto-8-O-methyl-chiro-inositol.
The most preferred compounds of the present invention are allo-inositol and scyllo-inositol, with scyllo-inositol being the most preferred. As indicated above, the inositol stereoisomers of the present invention exclude myo-inositol and may also exclude epi-inositol.
Even when given after the amyloid pathology has been well established for several months, these compounds effectively reverse cerebral Aβ accumulation and amyloid pathology.
Accordingly, these compounds are found to be useful in treating or preventing in a subject a condition of the central or peripheral nervous system or systemic organ associated with a disorder in protein folding or aggregation, or amyloid formation, deposition, accumulation, or persistence. These compounds are also found to be useful in preventing abnormal protein folding, abnormal protein aggregation, amyloid formation, deposition, accumulation, or persistence, or amyloid lipid interactions as well as causing the dissociation of abnormally aggregated proteins and/or dissolving or disrupting pre-formed or pre-deposited amyloid fibril or amyloid in a subject.
Preferably, the condition of the central or peripheral nervous system or systemic organ results in the deposition of proteins, protein fragments and peptides in beta-pleated sheats and/or fibrils and/or aggregates. More preferably, the condition of the central or peripheral nervous system or systemic organ is selected from the group of: Alzheimer's disease, presenile and senile forms; amyloid angiopathy; mild cognitive impairment; Alzheimer's disease-related dementia; tauopathy; α-synucleinopathy; Parkinson's disease; Amyotrophic Lateral Sclerosis; motor neuron Disease; Spastic paraplagia; Huntington's Disease, spinocerebellar ataxia, Freidrich's Ataxia; neurodegenerative diseases associated with intracellular and/or intraneuronal aggregates of proteins with polyglutamine, polyalanine or other repeats arising from pathological expansions of tri- or tetra-nucleotide elements within corresponding genes; cerebrovascular diseases; Down's syndrome; head trauma with post-traumatic accumulation of amyloid beta peptide; Prion related disease; Familial British Dementia; Familial Danish Dementia; Presenile Dementia with Spastic Ataxia; Cerebral Amyloid Angiopathy, British Type; Presenile Dementia With Spastic Ataxia Cerebral Amyloid Angiopathy, Danish Type; Familial encephalopathy with neuroserpin inclusion bodies (FENIB); Amyloid Polyneuropathy; Inclusion Body myositis due to amyloid beta peptide; Familial and Finnish Type Amyloidosis; Systemic amyloidosis associated with multiple myeloma; Familial Mediterranean Fever; chronic infections and inflammations; and Type II Diabetes Mellitus associate with islet amyloid polypeptide (IAPP).
Also preferably, the Alzheimer's disease-related dementias are vascular or Alzheimer dementia and tauopathy selected from the group of argyrophilic grain dementia, corticobasal degeneration, dementia pugilistica, diffuse neurofibrillary tangles with calcification, frontotemporal dementia with parkinsonism, Prion-related disease, Hallervorden-Spatz disease, myotonic dystrophy, Niemann-Pick disease type C, non-Guamanian Motor Neuron disease with neurofibrillary tangles, Pick's disease, postencephalitic parkinsonism, prion protein cerebral amyloid angiopathy, progressive subcortical gliosis, progressive supranuclear palsy, subacute sclerosing panencephalitis, and tangle only dementia.
Also preferably, the α-synucleinopathy is selected from the group of dementia with Lewy bodies, multiple system atrophy with glial cytoplasmic inclusions, Shy-Drager syndrome, striatonigral degeneration, olivopontocerebellar atrophy, neurodegeneration with brain iron accumulation type I, olfactory dysfunction, and amyotrophic lateral sclerosis.
Again preferably, the Motor Neuron Disease is associated with filaments and aggregates of neurofilament and/or superoxide dismutase proteins, the Spastic paraplegia is associated with defective function of chaperones and/or triple A proteins and the spinocerebellar ataxia is DRPLA or Machado-Joseph Disease.
Also preferably, the Prion related disease is selected from the group of Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease, and variant Creutzfeldt-Jakob disease and the Amyloid Polyneuropathy is Senile amyloid polyneuropathy or Systemic Amyloidosis.
More preferably, the condition of the central or peripheral nervous system or systemic organ is Parkinson's disease including familial and non-familial types. Most preferably, said condition of the central or peripheral nervous system or systemic organ is Alzheimer's disease.
Preferably, the compound is administered to the subject at a dose of about 1 mg to about 1 g per kg, preferably 1 mg to about 200 mg per kg, more preferably about 10 mg to about 100 mg per kg and most preferably about 30 mg to 70 mg per kg of the weight of said subject. The administration can be accomplished by a variety of ways such as orally (oral pill, oral liquid or suspension), intravenously, intramuscularly, intraperitoneally, intradermally, transcutaneously, subcutaneously, intranasally, sublingually, by rectal suppository or inhalation, with the oral administration being the most preferred. The administration of the compounds of the present invention can be undertaken at various intervals such as once a day, twice per day, once per week, once a month or continuously.
Preferably, the compounds of the present invention are administered in combination with other treatments such as beta-secretase inhibitors, gamma-secretase inhibitors (APP-specific or non-specific), epsilon-secretase inhibitors (APP-specific or non-specific), other inhibitors of beta-sheet aggregation/fibrillogenesis/ADDL formation (e.g. Alzhemed), NMDA antagonists (e.g. memantine), non-steroidal anti-inflammatory compounds (e.g. Ibuprofen, Celebrex), anti-oxidants (e.g. Vitamin E), hormones (e.g. estrogens), nutrients and food supplements (e.g. Gingko biloba); acetylcholinesterase inhibitors (e.g. donezepil), muscarinic agonists (e.g. AF102B (Cevimeline, EVOXAC), AF150(S), and AF267B), anti-psychotics (e.g. haloperidol, clozapine, olanzapine); anti-depressants including tricyclics and serotonin reuptake inhibitors (e.g. Sertraline and Citalopram Hbr), gene therapy and/or drug based approaches to upregulate neprilysin (an enzyme which degrades Aβ); gene therapy and/or drug based approaches to upregulate insulin degrading enzyme (an enzyme which degrades Aβ), vaccines, immunotherapeutics and antibodies to Aβ (e.g. ELAN AN-1792), statins and other cholesterol lowering drugs (e.g. Lovastatin and Simvastatin), stem cell and other cell-based therapies, inhibitors of kinases (CDK5, GSK3α, GSK3β) that phosphorylate TAU protein (e.g. Lithium chloride), or inhibitors of kinases that modulate Aβ production (GSK3α, GSK3β, Rho/ROCK kinases) (e.g. lithium Chloride and Ibuprofen).
It is believed that these other therapies act via a different mechanism and may have additive/synergistic effects with the present invention. In addition, many of these other therapies will have mechanism-based and/or other side effects which limit the dose or duration at which they can be administered alone.
Because of their ability to bind amyloids in vivo as discussed hereinbelow in more detail, the compounds of the present invention are also useful in diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in a subject using a method that comprises administering to said subject a radioactive compound or compound tagged with a substance that emits a detectable signal in a quantity sufficient and under conditions to allow for the binding of said compound to the abnormally folded or aggregated protein and/or fibrils or amyloid, if present; and detecting the radioactivity or the signal from the compound bound to the abnormally folded or aggregated protein and/or fibrils or amyloid, thus diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid.
Alternatively, a sample suspected of containing abnormally folded or aggregated protein and/or amyloid fibril or amyloid is collected from a subject and is contacted with a radioactive compound or compound tagged with a substance that emits a detectable signal under conditions to allow the binding of said compound to the abnormally folded or aggregated protein and/or amyloid fibril or amyloid if present; and thereafter detect the radioactivity or the signal from the compound bound to the abnormally folded or aggregated protein and/or fibrils or amyloid, thus diagnosing the presence of abnormally folded or aggregated protein and/or amyloid fibril or amyloid in said subject.
Preferably, said detectable signal is a fluorescent or an enzyme-linked immunosorbent assay signal and said sample is whole blood (including all cellular constituents) or plasma.
As shown hereinbelow, the compounds of the present invention can abrogate the cerebral accumulation of Aβ, the deposition of cerebral amyloid plaques, and cognitive decline in a transgenic mouse model of Alzheimer Disease when given during the “late presymptomatic” phase, prior to the onset of overt cognitive deficits and amyloid neuropathology in these mice. Furthermore, even when these compounds are given after the onset of cognitive deficits and amyloid plaque neuropathology, they can effectively reverse the amyloid deposition and neuropathology. Importantly, the mechanism of action of these compounds follows a rational design based upon their capacity to modulate the assembly of Aβ monomers into neurotoxic oligomers and/or protofibrils.
Other advantages of the compounds of the present invention include the fact that they are transported into the CNS by both known transporters and by passive diffusion, and therefore provide ready CNS bioavailablility. Second, these compounds are catabolized to glucose. Third, as a class, these compounds generally have low toxicity profiles, and some of them have previously been given to humans albeit for a different purpose.
Example 1 Development of Alzheimer's Mouse Model and Methods of Administering Compounds of the Present InventionTgCRND8 mice are a robust murine model of Alzheimer's disease as described by Janus et al. (Nature 408:979-982 (2000). They express a human amyloid precursor protein (APP695) transgene under the regulation of the Syrian hamster prion promoter on a C3H/B6 outbred background. The human APP695 transgene bears two mutations that cause AD in humans (K670N/M671L and V717F). Beginning at about 3 months of age, TgCRND8 mice have progressive spatial learning deficits that are accompanied by rising cerebral Aβ levels and by increasing number of cerebral extracellular amyloid plaques that are similar to those seen in the brains of humans with AD (C. Janus et al., Nature 408:979-982 (2000)).
Age and sex-matched cohorts of TgCRND8 mice and non-transgenic littermates (n=35 in each cohort) were either untreated, or were given a compound of the present invention as indicated below at 30 mg/day/mouse beginning at age of about 6 weeks. The mice were followed for outcome measures cognitive function, brain Aβ levels, brain pathology, and survival at 4 months and 6 months of age.
Prevention Studies MethodsMice—Experimental groups of TgCRND8 mice were fed myo-, epi- and scyllo-inositol at 30 mg/mouse/day. Two cohorts entered the study at 6 weeks of age and outcomes were analyzed at 4- and 6-months of age. The body weight, coat characteristics and in cage behavior was monitored. All experiments were performed according to the Canadian Council on Animal Care guidelines.
Behavioral tests—After non-spatial pre-training, mice underwent place discrimination training for 5 days with 4 trials per day. Behavioral data was analyzed using a mixed model of factorial analysis of variance (ANOVA) with drug or genotype and training sessions as repeated measure factors.
Cerebral amyloid burden—Brains were removed and one hemisphere was fixed in 4% paraformaldehyde and embedded in paraffin wax in the mid saggital plane. To generate sets of systematic uniform random sections, 5 μm serial sections were collected across the entire hemisphere. Sets of sections at 50 mm intervals were used for analyses (10-14 sections/set). Plaque were identified after antigen retrieval with formic acid, and incubated with primary anti-Aβ antibody (Dako M-0872), followed by secondary antibody (Dako StreptABCcomplex/horseradish kit). End products were visualized with DAB counter-stained with hematoxylin. Amyloid plaque burden was assessed using Leco IA-3001 image analysis software interfaced with Leica microscope and Hitachi KP-M1U CCD video camera. Vascular burden was analyzed similarly and a dissector was used to measure the diameter of affected vessels.
Plasma and Cerebral Aβ Content—Hemi-brain samples were homogenized in a buffered sucrose solution, followed by either 0.4% diethylamine/100 mM NaCl for soluble Aβ levels or cold formic acid for the isolation of total Aβ. After neutralization the samples were diluted and analyzed for Aβ40 and Aβ42 using commercially available kits (BIOSOURCE International). Each hemisphere was analyzed in triplicate with the mean±SEM reported. Western blot analyses were performed on all fractions using urea gels for Aβ species analyses. Aβ was detected using 6E10 (BIOSOURCE International) and Enhanced Chemiluminenscence (Amersham).
Analysis of APP in brain—Mouse hemi-brain samples were homogenized in 20 mM Tris pH7.4, 0.25M sucrose, 1 mM EDTA and 1 mM EGTA, and a protease inhibitor cocktail, mixed with 0.4% DEA (diethylamine)/100 mM NaCl and spun at 109,000×g. The supernatants were analysed for APPs levels by Western blotting using mAb 22C11, while the pellets were analysed for APP holoprotein using mAb C1/6.1.
Gliosis Quantitation—Five randomly selected, evenly spaced, sagittal sections were collected from paraformaldehyde-fixed and frozen hemispheres of treated and control mice. Sections were immunolabelled for astrocytes with anti-rat GFAP IgG2a (Dako; diluted 1:50) and for microglia with anti-rat CD68 IgG2b (Dako; 1:50). Digital images were captured using a Coolsnap digital camera (Photometrics, Tuscon, Ariz.) mounted to a Zeiss Axioscope 2 Plus microscope. Images were analysed using Openlab 3.08 imaging software (Improvision, Lexington Mass.).
Survival Census—The probability of survival was assessed by the Kaplan-Meier technique, computing the probability of survival at every occurrence of death, thus making it suitable for small sample sizes. For the analyses of survival, 35 mice were used for each treatment group. The comparison between treatments was reported using the Tarone-Ware test.
Example 2 Prevention of Cognitive DeficitsThe cognitive function of TgCRND8 mice was assessed using the spatial reference memory version of the Morris Water Maze using a five-day trial paradigm (
At four months of age, untreated TgCRND8 mice have a robust expression of both Aβ40 and Aβ42 (Table 1). Epi-inositol treatment as described in Example 1 reduced both Aβ 40 (43±2% reduction in both soluble and insoluble pools; p. 0.05) and Aβ 42 levels (69% reduction in soluble pool, p=0.005; 28% reduction in insoluble pool, p=0.02) at 4-months of age. However, these improvements were not sustained, and by 6 months of age, brain Aβ levels rose to levels similar to those observed in untreated TgCRND8 mice (Table 1).
In contrast, at four months of age, scyllo-inositol treatment decreased total brain Aβ40 by 62% (p=0.0002) and total brain Aβ42 by 22% (p=0.0096; Table 1). At 6 months of age, scyllo-inositol treatment caused a 32% reduction in Aβ40 levels (p=0.04) and 20% reduction in Aβ42 (p=0.02) compared to untreated TgCRND8 mice.
Because the decreased Aβ concentrations detected after inositol treatment could have resulted from altered efflux of Aβ into the plasma, Aβ-β levels in the plasma were examined at 4- and 6-months of age (Table 1). TgCRND8 mice have high plasma Aβ concentrations at 4-months of age and remain constant at 6 months of age even though CNS plaque load is still rising at 6-months of age (Table 1). Neither epi-inositol nor scyllo-inositol treatment had any effect on plasma Aβ levels in comparison to untreated TgCRND8 mice (p=0.89). The most parsimonious explanation for this observation is that the inositols have selectively altered the fibrillization of Aβ in the CNS, but have not affected β- or γ-secretase activity, or the normal mechanisms for clearance of Aβ into plasma. Nevertheless, this observation is significant for two reasons. First, a drop in plasma and CSF Aβ levels is usually detected as the clinical course progresses in untreated AD patients (Mayeux, et al., Ann. Neurol 46, 412, 2001). Secondly, patients in the AN1792 immunization study who developed a strong antibody response and an apparent clinical response did not have altered plasma Aβ-β levels (Hock et al., Neuron 38, 547 2003). Therefore, these results indicate that it is not necessary to change plasma Aβ levels to obtain an effective therapeutic outcome.
To confirm that inositol stereoisomers had no effect on either the expression or proteolytic processing of APP, the levels of APP holo-protein, sAPP-α, and various Aβ species were examined within the brain of inositol-treated and untreated TgCRND8 mice. Consistent with our previously reported data (McLaurin, et al., Nat. Med. 8, 1263, 2002), Aβ42, Aβ40 and Aβ38 are the predominant species in the brain of TgCRND8 mice (
The changes in Aβ-β peptide load were accompanied by a significant decrease in plaque burden (Table 1;
Astroglial and microglial reactions are neuropathological features both of human AD and of all amyloid mouse models (Irizarry et al., J Neuropathol Exp Neurol. 56, 965, 1997; K. D. Bornemann et al. Ann N Y Acad. Sci. 908, 260, 2000). Therefore, the effect of epi- and scyllo-inositol treatment was investigated on astrogliosis and microgliosis in the brains of TgCRND8 mice (
Alzheimer's disease is characterized by the presence of both parenchymal and vascular amyloid deposits. In untreated 6 month old TgCRND8 mice approximately 0.03% of the brain area is associated with vascular amyloid. No difference could be detected in the vascular amyloid burden after epi-inositol treatment at 6 months of age (
TgCRND8 mice have a 50% survival at 175 days, which after treatment was improved to 72% with scyllo-inositol (n=35 per group, p<0.02 for scyllo-inositol vs. control,
Taken together, the prevention studies demonstrate that scyllo-inositol inhibits both parenchymal and cerebrovascular amyloid deposition and results in improved survival and cognitive function in the TgCRND8 mouse model of Alzheimer disease. However, most Alzheimer's disease patients will likely seek treatment only once symptomatic, and when Aβ oligomerization, deposition, toxicity and plaque formation are already well advanced within the CNS. A pilot study was therefore initiated on 5 month old TgCRND8 mice. These mice have significant Aβ and plaque burdens that are comparable to those in the brain of humans with AD.
Treatment Study MethodsMice—Experimental groups of TgCRND8 mice were fed myo-, epi- and scyllo-inositol at 30 mg/mouse/day. A cohort entered the study at 5 months of age and outcomes were analyzed at 6-months of age. The body weight, coat characteristics and in cage behavior was monitored. All experiments were performed according to the Canadian Council on Animal Care guidelines.
Survival Census—The probability of survival was assessed by the Kaplan-Meier technique, computing the probability of survival at every occurrence of death, thus making it suitable for small sample sizes. For the analyses of survival, 35 mice were used for each treatment group. The comparison between treatments was reported using the Tarone-Ware test.
Behavioral. Test—Reversal Study—Mice entered the Morris water maze test with a hidden platform on day one without pretraining. Mice were tested for 3 days with six trials per day. On the fourth day, the platform was removed from the pool and each mouse received one 30-s swim probe trial. On the last day the animals underwent a cue test in order to evaluate swimming ability, eye sight and general cognition. The cue test is composed at the platform being placed in a different quadrant than that used for testing and is tagged with a flag. Animals are allowed 60 s to find the platform. Animals that do not find the platform are not used in the final analyses of spatial memory. Behavioural data was analysed using a mixed model of factorial analysis of variance (ANOVA) with drug or genotype and training sessions as repeated measure factors.
Cerebral amyloid burden—Brains were removed and one hemisphere was fixed in 4% paraformaldehyde and embedded in paraffin wax in the mid saggital plane. To generate sets of systematic uniform random sections, 5 μm serial sections were collected across the entire hemisphere. Sets of sections at 50 mm intervals were used for analyses (10-14 sections/set). Plaque were identified after antigen retrieval with formic acid, and incubated with primary anti-Aβ antibody (Dako M-0872), followed by secondary antibody (Dako StreptABCcomplex/horseradish kit). End products were visualized with DAB counter-stained with hematoxylin. Amyloid plaque burden was assessed using Leco IA-3001 image analysis software interfaced with Leica microscope and Hitachi KP-M1U CCD video camera.
Plasma and Cerebral Aβ Content—Hemi-brain samples were homogenized in a buffered sucrose solution, followed by either 0.4% diethylamine/100 mM NaCl for soluble Aβ levels or cold formic acid for the isolation of total Aβ. After neutralization the samples were diluted and analyzed for Aβ40 and Aβ42 using commercially available kits (BIOSOURCE International). Each hemisphere was analyzed in triplicate with the mean±SEM reported.
Results and Significance—All animals that entered the reversal study survived and did not display outward signs of distress or toxicity. The cognitive function of TgCRND8 mice was assessed using the spatial reference memory version of the Morris Water Maze using a three day trial paradigm (
In order to determine if the improved cognition was associated with decreased plaque burden and Aβ load, brain tissue was examined post-mortem. The changes in cognition were accompanied by a corresponding change in plaque burden and Aβ load (
Because the decreased Aβ concentrations detected after inositol treatment could have resulted from altered efflux of Aβ into the plasma, we examined Aβ levels in the plasma (Table 2). TgCRND8 mice have high plasma Aβ concentrations at 6 months of age. Neither myo-inositol, epi-inositol nor scyllo-inositol treatment had any effect on plasma Aβ levels in comparison to untreated TgCRND8 mice (p=0.89). The most parsimonious explanation for this observation is that the inositols have selectively altered the fibrillization of Aβ in the CNS, but have not affected β- or γ-secretase activity, or the normal mechanisms for clearance of Aβ into plasma. Nevertheless, this observation is significant for two reasons. First, a drop in plasma and CSF Aβ levels is usually detected as the clinical course progresses in untreated AD patients. Secondly, patients in the AN1792 immunization study who developed a strong antibody response and an apparent clinical response did not have altered plasma Aβ levels. Therefore, these results further indicate that it is not necessary to change plasma Aβ levels to obtain an effective therapeutic outcome.
Taken together, these data reveal that selected scyllo-inositol can abrogate the cerebral accumulation of Aβ, the deposition of cerebral amyloid plaques, and cognitive decline in a transgenic mouse model of Alzheimer Disease when given during the “late presymptomatic” phase, prior to the onset of overt cognitive deficits and amyloid neuropathology in these mice. Furthermore, even when scyllo-inositol is given after the onset of cognitive deficits and amyloid plaque neuropathology, these compounds can effectively reverse the amyloid deposition, neuropathology and cognitive deficits. Therefore, these results indicate that scyllo-inositol is effective at both prevention of disease and in the treatment of existing disease in patients already diagnosed with AD.
In order to determine longer efficacy ranges of scyllo-inositol for the treatment of disease, 5-month old TgCRND8 mice were fed scyllo-inositol or untreated for two months (n=10 per group). The cognitive function of 7-month old TgCRND8 mice treated with scyllo-inositol was compared to untreated TgCRND8 and treated non-Tg littermates in the three-day paradigm of the Morris Water Maze. Behavioural data was analysed using a mixed model of factorial analysis of variance (ANOVA) with drug and genotype as between subject variables and training sessions as within subject variable. As was seen with the 1-month treatment of scyllo-inositol (
5-month old TgCRND8 mice were gavaged once daily with scyllo-inositol in water at doses of 10 mg/Kg, 30 mg/Kg, 100 mg/Kg or untreated. Animals were sacrificed after one month of treatment and analysed for pathological outcomes. Analysis of the levels of Aβ within the brain of all the cohorts demonstrates that all drug doses were effective to the same extent on lowering soluble Aβ42 levels in comparison to untreated TgCRND8 mice (20% reduction, F3,15=3.1, p=0.07;
To assess whether allo-inositol might also be effective in preventing further progression and/or might partially reverse a well-established AD-like phenotype, the start of treatment of the TgCRND8 mice was delayed until 5 months of age. Cohorts of TgCRND8 and non-transgenic littermates were either treated for 28 days with allo-inositol, or were untreated. In these experiments, the dosage and oral administration of compounds, and the behavioral and neurochemical assays were the same as those employed in the above treatment experiments.
The cohort of 6-month old allo-inositol-treated TgCRND8 mice performed significantly better than untreated TgCRND8 mice (F1,13=0.45, p=0.05; data not shown). The cognitive performance of 6-month old allo-inositol-treated TgCRND8 mice was still significantly different from that of their non-transgenic littermates (F1,13=5.9, p=0.05;
In order to rule out any deleterious effects of inositol treatment on blood chemistry and organ function, blood was analyzed after one month treatment with both scyllo- and allo-inositol (Table 5,6). The total protein, albumin, globulin, bilirubin, alkaline phosphatase, glucose, urea and creatinine were not significantly different between treatment groups or from untreated TgCRND8 mice. All levels fell within the normal range as determined for non-transgenic wild type mice. In addition hemolysis, icteria and lipemia were all normal. These results suggest that allo- and scyllo-inositol do not exhibit obvious deleterious effects on blood chemistry or organ function.
Tg PS1×APP mice are an enhanced model of Alzheimer's disease which express a mutant human PS1 transgene encoding two familial mutations (M146L and L286V) in conjunction with the human APP transgene encoding the Indiana and Swedish familial mutations. These animals develop robust expression of cerebral Aβ levels and amyloid deposition by 30-45 days of age. In a prophylactic trial, TgPS1×APP mice were treated with scyllo-inositol from weaning and were assessed for effects on neuropathology at 2 months of age (
In order to rule out the contribution of increased caloric intake or non-specific effects, TgCRND8 mice were treated with a simple sugar of similar molecular weight, mannitol. At 6 months of age, mannitol treated TgCRND8 mice were indistinguishable from untreated TgCRND8 mice (
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. The present invention therefore is not limited by the specific disclosure herein, but only by the appended claims.
Claims
1. A method of treating or preventing in a subject a condition of the central or peripheral nervous system or systemic organ associated with a disorder in protein folding or aggregation, or amyloid formation, deposition, accumulation, or persistence comprising administering to said subject a pharmaceutically effective amount of a compound having the following structure: providing that the compound is not myo-inositol.
- wherein each of R1, R1′, R2, R2′, R3, R3′, R4, R4′, R5, R5′, R6, and R6′ is independently selected from the group of:
- (a) hydrogen atom;
- (b) NHR7, wherein said R7 is selected from the group of hydrogen; C2-C10 acyl and C1-C10 alkyl;
- (c) NR8R9, wherein said R8 is C2-C10 acyl or C1-C10 alkyl and said R9 is C2-C10 acyl or C1-C10 alkyl;
- (d) OR10, wherein said R10 is selected from the group of no group, hydrogen, C2-C10 acyl, C1-C10 alkyl and SO3H;
- (e) C5-C7 glycosyl;
- (f) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OH, NH2, SH, OSO3H and OPO3H2;
- (g) SR11, wherein R11 is selected from the group of hydrogen, C1-C10 alkyl and O3H;
- (h) C1-C10 alkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8R9 and SR11; and
- (i) C3-C8 cycloalkyl optionally substituted with a substituent selected from the group of hydrogen, OR10, NHR7, NR8, R9 and SR11,
2.-201. (canceled)
Type: Application
Filed: Feb 29, 2012
Publication Date: Jun 21, 2012
Inventor: JoAnne McLAURIN (East York)
Application Number: 13/408,337
International Classification: A61K 31/047 (20060101); A61P 25/28 (20060101); A61P 25/00 (20060101);
