METHOD FOR STIMULATING HEMATOPOIESIS USING TGF-ALPHA

Abstract

There is disclosed a novel genus of small peptides, much smaller than TGF&agr;, was discovered as having TGF&agr; biological activity and therefore are useful as pharmacologic agents for the same indications as full length TGF&agr; polypeptide. There is further disclosed that TGF&agr; and consequently the genus of small peptides disclosed herein, was found to have therapeutic activity to stimulate hematopoiesis in patients undergoing cytotoxic cancer chemotherapy and to act as a cytoprotective agent to protect a patient undergoing cancer cytotoxic therapy from gastrointestinal (GI) side effects, such as mucositis and otherwise support the barrier function of the GI tract when it is harmed by cytotoxic therapy.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention provides a novel peptide that is derived from a loop or “lollipop” region of transforming growth factor alpha (TGF-&agr;) and is biologically active for causing stem cells to proliferate and migrate. The present invention further provides a method for augmenting hematopoiesis, particularly trilineage hematopoiesis, and a method for suppressing immune functioning associated with autoimmune diseases, and a method for suppressing inflammatory responses mediated (in part) by excessive histamine release, comprising administering an effective amount of a TGF-&agr; polypeptide or a fragment thereof, such as the lollipop region. The present invention further provides a method for treating or preventing mucositis and gastrointestinal side effects in patients undergoing cancer treatment, comprising administering an effective amount of a TGF-&agr; polypeptide or a fragment thereof, such as the lollipop region.

BACKGROUND OF THE INVENTION

[0002] There are several disease treatments that could significantly benefit by having cells regenerate after injury or lesion formation, particularly in the CNS, in the immune system and in the gastrointestinal tract. The expression of growth factors and their receptors in the pre-implanted human embryo and maternal reproductive tract indicates that such factors influence growth and differentiation of embryonic cells in an autocrine and paracrine manner. Such growth factors are peptides that variously support survival, proliferation, differentiation, size and function of nerve cells and other lineages of cells. EGF (epidermal growth factor) is the first member found of the EGF family and characterized many years ago (Savage and Cohen, J. Biol. Chem. 247:7609-7611, 1972; and Savage et al., J. Biol. Chem. 247:7612-7621, 1972). Additional members of the EGF family have been found and they include vaccinia virus growth factor (VGF; Ventatesan et al., J. Virol. 44:637-646, 1982); myxomavirus growth factor (MGF; Upton et al. J. Virol. 61:1271-1275, 1987), Shope fibroma virus growth factor (SFGF; Chang et al., Mol. Cell. Biol. 7:535-540, 1987), amphiregulin (AR; Kimura et al., Nature 348:257-260, 1990), and heparin binding EGF-like factor (HB-EGF; Higashiyama et al., Science 251:936-939, 1991). A common structural feature of these polypeptides is the presence of six cysteine residues that form three disulfide cross links that support a conserved structure that binds to the EGF receptor.

[0003] Another member of the EGF family is TGF&agr; and it also binds to the EGF receptor (Todaro et al., Proc. Natl. Acad. Sci. USA 77:5258-5262, 1980). TGFU stimulates the EGF receptor's tyrosine kinase activity and has many cellular functions, such as stimulating a mitogenic response in a wide variety of cell types. TGF&agr; and EGF mRNAs reach their highest levels and relative abundance (compared to total RNA in the early postnatal period and decrease thereafter, suggesting a role in embryonic development. From a histological perspective, TGF&agr; acts on numerous cell types throughout the body. The active form of TGF&agr; is derived from a larger precursor and contains 50 amino acids. TGF&agr; shares only a 30% structural similarity with the 53-amino acid form of EGF, but including conservation of all six cysteine residues. TGF&agr; is highly conserved among species. For example, the rat and human polypeptides share about 90% homology as compared to a 70% homology as between the rat and human EGF polypeptide. The amino acid sequence of TGF&agr; is shown in SEQ ID NO. 1. The sequence shows that a family consisting of vaccinia growth factor, amphiregulin precursor, betacellulin precursor, heparin binding EGF-like growth factor, epiregulin (rodent only), HUS 19878 and schwannoma derived growth factor have similar sequence motifs and can be considered as members of the same family based upon their shared cysteine disulfide bond structures.

[0004] TGF&agr; is an acid and heat stable polypeptide of about 5.6 kDa molecular weight. It is synthesized as a larger 30-35 kDa molecular weight glycosylated and membrane-bound precursor protein wherein the soluble 5.6 kDa active form is released following specific cleavage by an elastase-like protease. TGF&agr; binds with high affinity in the nanomolar range and induces autophosphorylation to transduce signal with the EGF receptor. TGF&agr; is 50 amino acids in length and has three disulfide bonds to forms its tertiary configuration. All three disulfide bonds must be present for activity. TGF&agr; is stored in precursor form in alpha granules of secretory cells. Moreover, the primary amino acid sequence is highly conserved among various species examined, such as more than 92% homology at the amino acid level as between human and rat TGF&agr; polypeptides.

[0005] TGF&agr; has been investigated extensively and has recently been identified as useful for treating a patient with a neurological deficit. This mechanism is thought to stimulate proliferation and migration of neural-origin stem cells to those site or lesions in a deficit. For example, Parkinson's Disease is characterized by resting tremor, rigidity, inability to initiate movement (akinesia) and slowness of movement (bradykinesia). The motor deficits are associated with progressive degeneration of the dopaminergic innervation to the nucleus accumbens and degeneration of noradrenergic cells of the locus ceruleus and serotonergic neurons of the raphe. Up to 80% of nigral dopamine neurons can be lost before significant motor deficits are manifest. TGF&agr; (full polypeptide) was shown, when infused into rat brains, was useful for the treatment of neurodegenerative disorders. Intracerebroventricular (ICV) or intrastriatal infusions of TGF&agr; induced neuronal stem cell proliferation, but degenerating or damaged or otherwise abnormal cells needed to be present to facilitate migration of the neuronal stem cells to a site of injury on a scale sufficient to impact recovery from an associated neurological deficit. Forebrain neural stem cells, that give rise to migrating progenitor cells that affect treatment and recovery from a neurological deficit disorder, are the migrating cells that affect treatment recovery from a neural deficit disorder (e.g., Parkinson's Disease, Huntington's Disease, Alzheimer's Disease and the like).

[0006] Neural stem cells have been found in subependyma throughout the adult rodent CNS (Ray et al. Soc. Neurosci. 22:394.5, 1996) and in the subependyma of adult human forebrain (Kirschenbaum et al., Cerebral Cortex 4:576-589, 1994). Thus, the discovery that TGF&agr; stimulates proliferation of neural stem cells and promotes migration to a site of injury or deficit has led to its investigation for the treatment of a neurodegenerative disorder (Alzheimer's Disease, Huntington's Disease and Parkinson's Disease) or CNS traumatic injury (e.g., spinal chord injury), demyelinating disease, CNS inflammatory disease, CNS autoimmune disease (e.g., multiple sclerosis) or CNS ischemic disease (e.g., stroke or brain attack).

[0007] A CNS stem cell has the potential to differentiate into neurons, astrocytes and to exhibit replication of itself to provide a resource for self-renewal. Both neurons and glial cells seen to be derived from a common fetal precursor cell. In the vertebrate CNS, multipotential cells have been identified in vitro and in vivo. Certain mitogens, such as TGF&agr;, can cause proliferation of CNS mutipotential cells in vitro and this is the basis for a procedure to harvest such cell, treat them ex vivo to stimulate proliferation in culture and then readminister such cells. Immunohistochemical analysis in the human brain supports the notion that TGF&agr; is widely distributed in neurons and glial cells both during development and during adulthood. In mice genetically altered to lack expression of functioning TGF&agr;, there was a decrease in neural progenitor cell proliferation in forebrain subependyma, providing evidence for TGF&agr; as a proliferative factor for neural progenitor cells.

[0008] TGF&agr; is found mainly in various neurons of the CNS during development and in the adult brain in the cerebral neocortex, hippocampus and striatum. It is also found in a few glial cells, primarily in the cerebral and cerebellar cortex areas. Northern blot analyses showed that TGF&agr; and not EGF (epidermal growth factor) is the most abundant ligand that binds to the EGF receptor in the brain. TGF&agr; mRNA levels were 15-170 times higher than EGF in cerebellum and cerebral cortex. TGF&agr; also appears in germinal centers of the brain during neurogenesis and gliogenesis in the developing brain. In the midbrain, the distribution of TGF&agr; overlaps with tyrosine hydroxylase mRNA and fetal dopaminergic neurons. In culture, TGF&agr; enhanced survival and neurite outgrowth of neonatal rat dorsal ganglion neurons (EGF did not) and survival and differentiation of CNS neurons. TGF&agr; induced proliferation of neural precursor cells of the murine embryonic mesencephalon and further induced a significant increase in the number of astroglia and microglia in fetal rat medial septal cells. TGF&agr; increased glutamic acid decarboxylase activity and decreased choline actetyltransferase activity. Thus, TGF&agr; acted as a general neuronal survival factor affecting both cholinergic and GABAergic neurons. In addition, TGF&agr; is a mitogen for pluripotent brain stem cells. Forebrain subependyma contains nestin positive neural stem cells and their progeny, which are constitutively proliferating progenitor epithelial cells. A “knockout” mouse that was genetically engineered to delete the gene for TGF&agr; showed a reduction in neuronal progenitor cells in the subependyma and a reduction in neuronal progenitors that migrate to the olifactory bulb. In vitro, TGF&agr; promoted dopamine uptake in fetal rat dopaminergic neurons in a dose-dependent and time-dependent manner. TGF&agr; selectively promoted dopaminergic cell survival, enhanced neurite length, branch number and the soma area of tyrosine hydroxylase immunopositive cells. The levels of TGF&agr; were elevated in ventricular cerebrospinal fluid in juvenile parkinsonism and Parkinson's Disease and may represent a compensatory response to neurodegeneration. Further, TGF&agr; prevented a striatal neuronal degeneration in an animal model of Huntington's Disease.

[0009] The mucosal epithelium of the intestine is in a continually dynamic state known as “epithelial renewal” in which undifferentiated stem cells from a proliferative crypt zone divide, differentiate and migrate to the luminal surface. Once terminally differentiated, they are sloughed from the tips of the villi. The turnover of the crypt-villus cell population is rapid and occurs every 24-72 hours. Continuous exfoliation of the cells at the villus tip is counterbalanced by ongoing proliferation in the crypt so that net intestinal epithelial mass remains relatively constant. The rapidly-proliferating epithelium of the gastrointestinal tract is extremely sensitive to cytotoxic drugs that are widely used in the chemotherapy of cancer. This “side effect” reduces the tolerated dose of such drugs as it can cause a breakdown of the GI barrier function and septic condition in a patient already immuno-compromised. This can also lead to life-threatening hemorrhage. Therefore, there is a need in the art for the development of products and delivery systems that stimulate the repair and rejuvenation of mucosal epithelium in the gastrointestinal tract to provide benefit to patient receiving chemotherapy and radiation therapy for cancer.

[0010] Therefore, there is a need in the art to find improved TGF&agr; mimetic agents that are more economical to produce and are smaller (in terms of molecular weight). The present invention was made to address such a need.

SUMMARY OF THE INVENTION

[0011] The present invention is based upon two basic discoveries that have not been reported before in the extensive literature of TGF&agr; . Firstly, a novel genus of small peptides, much smaller than TGF&agr;, was discovered as having TGF&agr; biological activity and therefore are useful as pharmacologic agents for the same indications as full length TGF&agr; polypeptide. Secondly, TGF&agr; and consequently the genus of small peptides disclosed herein, was found to have therapeutic activity to stimulate hematopoiesis in patients undergoing cytotoxic cancer chemotherapy and to act as a cytoprotective agent to protect a patient undergoing cancer cytotoxic therapy from gastrointestinal (GI) side effects, such as mucositis and otherwise support the barrier function of the GI tract when it is harmed by cytotoxic therapy.

[0012] The present invention provides a compound that acts as a TGF&agr; mimetic, comprising at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0013] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0014] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0015] The present invention further provides a pharmaceutical composition comprising a loop peptide in a pharmaceutically acceptable carrier, wherein the loop peptide compound comprises at least an 11 -membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0016] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0017] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0018] The present invention further provides a method for treating a neurodegenerative disease with an pharmaceutically active loop peptide, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0019] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0020] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0021] The present invention further provides a method for treating a CNS disease or disorder, wherein the CNS disease or disorder is selected from the group consisting of CNS ischemia, spinal cord injury, MS, and retinal injury, comprising with an pharmaceutically active loop peptide, wherein the loop peptide comprises at least an 1 1-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0022] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0023] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0024] The present invention further provides a method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0025] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0026] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly. Preferably, the invention further comprises administering a second hematopoietic growth factor agent to stimulate more mature hematopoietic precursor cells, wherein the second hematopoietic growth factor is selected from the group consisting of erythropoietin, thrombopoietin, G-CSF (granulocyte colony stimulating factor), and GM-CSF (granulocyte macrophage colony stimulating factor).

[0027] The present invention further provides a method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0028] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0029] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0030] The present invention further provides a bifunctional compound that acts as a TGF&agr; mimetic, comprising a compound from formula III:

Loop peptide N-terminus-linker-cyclic C4H8N2-linker-Loop peptide N-terminus  III

[0031] wherein the linker moiety is designed to link the N-terminus of the Loop peptide to a nitrogen atom of the ring C4H8N2 and wherein the “loop peptide” comprises at least an I1 -membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0032] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0033] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, the linker group is independently selected from the group consisting of substituted or unsubstituted C1-6 alkyl, substituted or unsubstituted C2-6 alkenyl, substituted or unsubstituted C1-6 alkoxy, xylenyl, wherein the substitutions are selected from the group consisting of oxo, epoxyl, hydroxyl, chloryl, bromyl, fluoryl, and amino Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0034] The present invention further provides a method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

[0035] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0036] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

[0037] The present invention further provides a method for treating an inflammatory reaction of autoimmune diseases, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N-X1a-Cys-His-Ser-X1b-X2-X1a-X1b-X1a-X3- Cys COOH  I

[0038] wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide. Preferably, the autoimmune diseases are selected from the group consisting of Type II (Juvenile) Diabetes, rheumatoid arthritis, lupus, and multiple sclerosis. Preferably, at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

[0039] wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu. Preferably, X1a is Val, X1b is Gly and X1c is Ala. Preferably, X2 is Tyr, and X3 is Arg. Most preferably, the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 shows the structure of human TGF&agr; polypeptide and its 50 amino acids arranged into three loops.

[0041] FIG. 2 shows a graph comparing TGF&agr; biological activity of the three loop peptide regions of TGF&agr; (see FIG. 1) wherein Loop A is amino acids 1-21 (starting at the N terminus), Loop B is amino acids 16 to 32 and Loop C is amino acids 33 to 50. Only Loop C showed significant TGF&agr; activity as determined by cell proliferation and in a dose response fashion.

[0042] FIG. 3 shows a graph of mouse spleen weights that were treated with Cis Platinum (CP) at either 5 &mgr;g/g or 10 &mgr;g/g and with TGF&agr; at concentrations of 10 ng/g or 50 ng/g. These data show that TGF&agr; treatment caused a return to normal spleen weights despite CP treatment that reduced spleen weights significantly.

[0043] In FIG. 4, three panels of H&E-stained spleens are shown. Specifically, the top panel shows a CP-treated mouse spleen (10 &mgr;g/g) showing apoptotic cells (densely stained with fragments of nuclei) in the germinal center (GC). The T cells with the central arterial area show the absence of a marginal zone and much fewer erythrocytes and T cells in the perifolecular area (arrows). In the middle panel, a normal mouse spleen is shown (no CO and no TGF&agr;) fixed in formalin showing an arteriole with T cells areas (arrow). A primary follicle and a second follicle are shown as containing a germinal center (GC). There is a presence of an erythrocyte rich (pink) perifollicular zone surrounding both a T cell and B cell compartments of white pulp. In the bottom panel, a mouse spleen treated with CP (10 &mgr;g/g) and TGF&agr; (50 ng/g) shows an increased number of T cells and erythrocytes in the perifolicular zone (arrows). The T cell area contains lymph vessels in relation to arterioles. A germinal center (GC) is within the mantle zone.

[0044] In FIG. 5 there are three panels showing the histological examination of mouse intestines. In the top panel, CP (single ip dose of 10 &mgr;g/g) treated intestine is cross-sectioned and shows significant injury to the villi. Specifically, the villi are necrotic and the crypts are in irregular shapes. The tips of the crypts were losing their cellular integrity (arrows). In the middle panel is a cross section of a normal mouse GI tract (no CP and no TGF&agr;) and shows a normal intestinal surface with villi having long and slender mucosal projections with a core of lamina propria covered by a luminal epithelial layer. A single row of intestinal crypt is found at the base of the mucosa. These crypts that lie between adjacent villi are surrounded by the same lamina propria that form the villous cores. Both columnar absorptive cells and globlet cells cover the villous surfaces. The globlet cells contain apical clear vacuoles. The bottom panel shows a cross section of a mouse intestine exposed both the CP (10 &mgr;g/g) and TGF&agr; (50 ng/g). The intestinal structure is very similar to the normal intestinal structure. Specifically, the villus is long and slender. Both absorptive cells and globlet cells are visible at the surface of the villi. There is an abundant amount of globlet cells on the surface.

[0045] In FIG. 6, there are three panels shown at 160× magnification again corresponding to a CP-treated mouse in the top panel, a normal mouse in the middle panel and a CP treated and TGF&agr; treated mouse in the bottom panel at the same doses as indicated for FIG. 5. In the top panel are injured villi with tips degenerating and necrotic (arrows). Red blood cells are observed in the damaged villi (arrows). The crypts (C) are in irregular shape and in various heights. The middle panel shows that the tips of the villi (arrows) are smooth and the nuclei of the enterocytes are observed throughout the villus. The crypts (C) are similar in height and regular in shape. The bottom panel has villi (arrows) appearing normal as in the middle panel. The crypts (C) also appear to be normal.

[0046] FIG. 7 shows three panels but the top and middle panels are CP (10 &mgr;g/g) treated without TGF&agr; and the bottom panel is CP (10 &mgr;g/g) and 50 ng/g of TGF&agr;. The panels are shown at higher magnification. In the top panel, the severely injured crypt surface from CP treatment shows cellular destruction due to necrosis. Red cells appear at the damaged surface to indicate intestinal bleeding. In addition, the middle panel of a CP-treated mouse shows a loss of brush border and very little of a glycocalyx or fuzzy coat. The interspersed globlet cells appear fewer in number (than normal) and are seen as necrotic. In the bottom panel, the effect of TGF&agr; treatment shows protection of the villa surface (arrows). Specifically, the epithelial cells are normal appearing with extended brush borders. The nuclei are very densely stained and elongated.

[0047] The histological data is summarized in FIG. 8 that measured average crypt height of the three groups of mice. TGF&agr; treatment (50 ng/g) was able to more-than-restore crypt height loss from CP treatment.

[0048] In FIG. 9, the three panels at 160× magnification are shown to correspond to normal intestine in the top panel, CP only treated (10 &mgr;g/g) in the middle panel and both CP (10 &mgr;g/g) and TGF&agr; (50 ng/g) in the bottom panel. In the normal intestine (top panel), each villus extends from the luminal surface to the basal muscularis mucosal surface. Globlet cells are scattered and predominate in the base of the villus (arrows) whereas columnar absorptive cells line the luminal surface. In the middle panel, the alcian blue staining method shows that the villi contain a fewer number of globlet cells (than normal) (arrows). The injured absorptive and globlet cells are degenerating at the tip of the villi (arrows). Abundant secretory mucus material is stained in the luminal surface (arrows). In the bottom panel, there is an increased number of globlet cells scattered throughout the villi (arrows). The intestinal villi are in normal form with elongation. The majority of enterocytes are not alcian blue stained positive. The luminal plasma membranes of the villi (arrows) are well protected by TGF&agr; treatment.

[0049] FIG. 10 shows that TGF&agr; treatment not only increased the number of globlet cells but increased the number from CP treatment to a higher level than normal intestine.

[0050] FIG. 11 shows that TGF&agr; treatment causes mast cells residing in the intestinal mucosal tissue and lamina propria to remain intact and thus not release histamine and other pro-inflammatory molecules. The bottom panel, by contrast, shows CP-treated mice who did not receive TGF&agr; wherein there was a degranulation of mast cells and subsequent induction of inflammatory responses.

DETAILED DESCRIPTION OF THE INVENTION

[0051] Loop Peptide

[0052] TGF&agr; is a polypeptide of 50 amino acids shown in FIG. 1. The TGF&agr; polypeptide can be divided roughly into three loop regions corresponding roughly (starting at the N terminus) to amino acids 1-21, to amino acids 16-32, and to amino acids 33-50. Each of the three foregoing loop regions was investigated for TGF&agr;-like biological activity, such as stimulation of cellular proliferation as measured by 3H thymidine incorporation of stem cells. As shown in FIG. 2, only the Loop C peptide (corresponding to amino acids 33-50) showed significant TGF&agr; biological activity and is therefore a TGF&agr; mimetic peptide. Therefore, in view of the fact that the loop peptide exhibits TGF&agr; biological activity, data obtained with TGF&agr; (50 amino acid polypeptide is predictive of activity of the loop peptide and similar loop peptides embodied in the genus of formula I with or without the addition of a “tail” region of formula II). These data predict activity for the loop peptide when activity is also shown for TGFU.

[0053] Pharmaceutical Composition and Formulations

[0054] The inventive pharmaceutical composition comprises a loop peptide in a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier is suitable for the particular form of administration contemplated by the pharmaceutical composition. The term “carrier” is designed to mean any and all solvents, dispersion media, coatings, isotonic agents, antibacterial and antifungal agents designed to preserve a formulation from contamination, absorption agents and similar agents that are compatible with pharmaceutical administration irrespective of the route of administration.

[0055] The pharmaceutical formulations are made based upon the intended routes of administration. Specifically, those formulations that will be intended for a GI indication will likely be administered orally. In view of the peptide bonds present, such formulations will be made to pass through the stomach and protect the active compound from the low pH conditions of the stomach before there is a better chance for local activity in the villi of the small intestine and large intestine. The loop peptide formulations are intended for parenteral administration through some form of injection or for use in ex vivo culture media. Parenteral forms of administration include, for example, intravenous, intradermal, intramuscular, intraperitoneal for GI effects, injection directly into a target organ (e.g., brain) at the appropriate location, application in a biodegradable matrix to a site of CNS injury (e.g., spinal cord).

[0056] Solutions or suspensions useful in the pharmaceutical compositions that contains peptide components include sterile diluents such as water, saline, fixed oils, polyethylene glycols, glycerine, propylene glycol, or other synthetic agents, plus an antibacterial or antifungal agent for preservation, antioxidants, chelating agents, buffer and agents that adjust tonicity for direct organ injections. Forms of pharmaceutical compositions include, for example, sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions of dispersions. For intravenous injection or direct organ or peritoneal injections, suitable carriers include, for example, saline, bacteriostatic water, Cremophor, or phosphate buffered saline. The composition is formulated to preserve stability, be easily mixed and preserved against contamination. Isotonic agents, such as sugars or polyalcohols (e.g., glucose, fructose, mannitol, sorbitol and the like) or sodium chloride are used. Agents that delay target organ absorption can also be used and these include, for example, aluminum monostearate and gelatin.

[0057] Sterile injectable solutions can be prepared by incorporating the active agent (see formula I, formula II, or formula III and TGF&agr;) in the required amount in an appropriate solvent and then sterilizing, such as by sterile filtration. Further, powders can be prepared by standard techniques such as freeze drying or vacuum drying.

[0058] In another embodiment, the active agent is prepared with a biodegradable carrier for sustained release characteristics for either sustained release in the GI tract or for target organ implantation (e.g., brain or spinal cord) with long term active agent release characteristics to the intended site of activity (such as a site of injury or neuronal degradation). Biodegradable polymers include, for example, ethylene vinyl acetate, polyanhydrides, polyglycolic acids, polylactic acids, collagen, polyorthoesters, and poly acetic acid. Liposomal formulation can also be used.

[0059] In addition, the active compound for the pharmaceutical composition needs to also be synthesized. If the compound is from formula I or formula II, a preferred means for synthesizing peptides of 13-18 amino acids in length is by direct peptide synthesis generally starting with the N-terminal amino acid and adding amino acids in the C terminal direction. Such small peptides can also be synthesized and later purified by standard recombinant techniques, but peptide of 18 amino acids in length are better synthesized from the amino acid building blocks directly. TGF&agr; has bee made using recombinant techniques and is available as a laboratory reagent commercially. The bifunctional compounds of formula III are best synthesized with each loop peptide moiety synthesized and then added to the heterocyclic nitrogen atom using standard heterocyclic addition synthesis

[0060] Loop Peptide Mimics TGF&agr; Neuroactive Therapeutic Activity

[0061] The neuroactive activity of the loop peptide is based upon the discovery that the loop peptide exhibits TGF&agr; biological activity and can therefore stimulate CNS multipotent precursor cells to divide and migrate through the brain. This activity indicates that the loop peptide is effective to treat neurological deficits caused by a wide variety of diseases and injuries that each result in a neurological deficit in some specific area of the brain or specific kind of neuron. These include degenerative diseases, including the more common Alzheimer's Disease (AD), Parkinson's Disease (PD), and Huntington's Disease (HD), and the less common Pick's disease, progressive supranuclear palsy, striatonigral degeneration, cortico-basal degeneration, olivopontocerebellar atrophy, Leigh's disease, infantile necrotizing encephalomyelopathy, Hunter's disease, mucopolysaccharidosis, various leukodystrophies (such as Krabbe's disease, Pelizaeus-Merzbacher disease and the like), amaurotic (familial) idiocy, Kuf's disease, Spielmayer-Vogt disease, Tay Sachs disease, Batten disease, Jansky-Bielschowsky disease, Reye's disease, cerebral ataxia, chronic alcoholism, beriberi, Hallervorden-Spatz syndrome, cerebellar degeneration, and the like.

[0062] Further, injuries (traumatic or neurotoxic) that cause a loss of neuronal function can be treated by the loop peptide. Such injuries include, for example, gunshot wounds, injuries caused by blunt force, penetration injuries, injuries caused by surgical procedure (e.g., tumor removal, abscess removal, epilepsy lesion removal) poisoning (e.g., carbon monoxide), shaken baby syndrome, adverse reactions to medications, drug overdoses, and post-traumatic encephalopathy. Ischemia can further cause CNS injury due to disruption of blood flow or oxygen delivery that can kill or injure neurons and glial cells. Such injuries can be treated by administration of the loop peptide and include, for example, injuries caused by stroke, anoxia, hypoxia, partial drowning, myoclonus, severe smoke inhalation, dystonias, and acquired hydrocephalus. Developmental disorders that can be treated by the loop peptide include, for example, schizophrenia, certain forms of severe mental retardation, cerebral palsey, congenital hydrocephalus, severe autism, Downs Syndrome, LHRH/hypothalamic disorder, and spina bifida. The loop peptide can be further used to treat disorders affecting vision caused by the loss or failure of retinal cells and include, for example, diabetic retinopathy, serious retinal detachment (associated with glaucoma), traumatic injury to the retina, retinal vascular occlusion, macular degeneration, optic nerve atrophy and other retinal degenerative diseases. Injuries to the spinal cord can be treated by the loop peptide. Examples of spinal cord injuries are post-polio syndrome, amyotrophic lateral sclerosis, traumatic injury, surgical injury, and paralytic diseases. Demylinating autoimmune disorders can be treated by administration of the loop peptide and include, for example, multiple sclerosis. Lastly, the loop peptide can be used to treat neurological deficits caused by infection of inflammatory diseases, including, for example, Creutzfeldt-Jacob disease and other slow virus infectious diseases of the CNS, AIDS encephalopathy, post-encephalitic Parkinsonism, viral encephalitis, bacterial meningitis and other CNS effects of infectious diseases.

[0063] The loop peptide provides TGF&agr; activity and therefor the present method of treating neurological deficit and injury disorders is based upon the biological activity of the loop peptide of formula I, formula II and formula III and the data available for TGF&agr; that has been published.

[0064] Hematopoiesis

[0065] TGF&agr; showed surprising activity in an in vivo model of general hematopoiesis when administered in conjunction with a potent cytotoxic agent Cis Platinum (CP). FIG. 3 shows a graph of mouse spleen weights that were treated with CP at either 5 &mgr;g/g or 10 &mgr;g/g and with TGF&agr; at concentrations of 10 ng/g or 50 ng/g. These data show that TGF&agr; treatment caused a return to normal spleen weights despite CP treatment that reduced spleen weights significantly. This in vivo experiment is a predictive model for hematopoiesis in humans as CP is a cytotoxic agent commonly used for cancer chemotherapy that is known to significantly reduce trilineage hematopoietic cells. Hematopoietic cells are red blood cell precursors, platelet precursors (megakaryocytes), and immune (white) blood cell precursors of various forms of T cells, B cells and macrophages. Moreover, platelet counts were higher in those mice injected with TGF&agr; (and CP) as opposed to CP alone were such counts were significantly reduced from normal.

[0066] The experiment procedure dosed those animals to be treated with TGF&agr; 4 hours prior to challenge with CP. A single dose of CP was administered. Additional doses (as indicated) of TGF&agr; were made at 24 hours, 48 hours, 72 hours and 96 hours after the CP dose. All doses were made by IP injection. Controls were dosed with saline instead of either or both of CP and TGF&agr;.

[0067] The animals were sacrificed about 4 hours after the last TGF&agr; (or saline) dose. Key organs were removed and spleens were immediately weighed after a clean incision. All the relevant organs were placed in formalin, transported for histopathological analysis, mounted, sectioned, stained and observed. The results of this histological analysis of the spleens for hematopoietic effect and the GI tract (below) provide the surprising data of the effect of TGF&agr; activity.

[0068] In FIG. 4, three panels of H&E-stained spleens are shown. Specifically, the top panel shows a CP-treated mouse spleen (10 &mgr;g/g) showing apoptotic cells (densely stained with fragments of nuclei) in the germinal center (GC). The T cells with the central arterial area show the absence of a marginal zone and much fewer erythrocytes and T cells in the perifolecular area (arrows). In the middle panel, a normal mouse spleen is shown (no CO and no TGF&agr;) fixed in formalin showing an arteriole with T cells areas (arrow). A primary follicle and a second follicle are shown as containing a germinal center (GC). There is a presence of an erythrocyte rich (pink) perifollicular zone surrounding both a T cell and B cell compartments of white pulp. In the bottom panel, a mouse spleen treated with CP (10 &mgr;g/g) and TGF&agr; (50 ng/g) shows an increased number of T cells and erythrocytes in the perifolicular zone (arrows). The T cell area contains lymph vessels in relation to arterioles. A germinal center (GC) is within the mantle zone. These in vivo data in a predictive model of hematopoiesis and confirmed by blinded histological analysis (the histologist/pathologist was blinded as to the treatment history of the coded tissues received) providing surprising evidence of the utility of peptides having TGF&agr; activity to augment hematopoiesis following cytotoxic exposure. These data predict and provide a reasonable correlation that TGF&agr; and the peptides of formula I, formula II and formula III are useful therapeutic agents for augmenting hematopoiesis following or during cytotoxic therapy, such as cancer treatment. Therefore, a useful method for treating cancer is to combine either TGF&agr; or a peptide from formula I, formula II or formula III or combinations thereof with cytotoxic treatment regimens to reduce dose-limiting side effects.

[0069] Mucositis and Gastrointestinal Diseases

[0070] The small intestine comprises the duodenum, jejunum and ileum. It is the principal site for absorption of digestive products from the GI tract. Digestion begins in the stomach and is completed in the small intestine in association with the absorptive process. The intestinal mucosa surface is made up of numerous finger-like projections called villi. In addition, mucosa between the basis of the villi (crypts) is formed into the crypts.

[0071] TGF&agr; or a peptide from formula I, formula II or formula III or combinations thereof are also useful for treating mucositis associated intestinal bleeding , dyspepsia associated with cytotoxic therapy and for improving the barrier function of the GI tract compromised by cytotoxic therapy. The in vivo experiment with seven groups of mice described above for hematopoietic effects noted in spleens also examined the GI tract of these treated mice. In FIG. 5 there are three panels showing the histological examination of mouse intestines. In the top panel, CP (single ip dose of 10 &mgr;g/g) treated intestine is cross-sectioned and shows significant injury to the villi. Specifically, the villi are necrotic and the crypts are in irregular shapes. The tips of the crypts were losing their cellular integrity (arrows). In the middle panel is a cross section of a normal mouse GI tract (no CP and no TGF&agr;) and shows a normal intestinal surface with villi having long and slender mucosal projections with a core of lamina propria covered by a luminal epithelial layer. A single row of intestinal crypt is found at the base of the mucosa. These crypts that lie between adjacent villi are surrounded by the same lamina propria that form the villous cores. Both columnar absorptive cells and globlet cells cover the villous surfaces. The globlet cells contain apical clear vacuoles. The bottom panel shows a cross section of a mouse intestine exposed both the CP (10 &mgr;g/g) and TGF&agr; (50 ng/g). The intestinal structure is very similar to the normal intestinal structure. Specifically, the villus is long and slender. Both absorptive cells and globlet cells are visible at the surface of the villi. There is an abundant amount of globlet cells on the surface.

[0072] In FIG. 6, there are three panels shown at 160× magnification again corresponding to a CP-treated mouse in the top panel, a normal mouse in the middle panel and a CP treated and TGF&agr; treated mouse in the bottom panel at the same doses as indicated for FIG. 5. In the top panel are injured villi with tips degenerating and necrotic (arrows). Red blood cells are observed in the damaged villi (arrows). The crypts (C) are in irregular shape and in various heights. The middle panel shows that the tips of the villi (arrows) are smooth and the nuclei of the enterocytes are observed throughout the villus. The crypts (C) are similar in height and regular in shape. The bottom panel has villi (arrows) appearing normal as in the middle panel. The crypts (C) also appear to be normal.

[0073] FIG. 7 shows three panels but the top and middle panels are CP (10 &mgr;g/g) treated without TGF&agr; and the bottom panel is CP (10 &mgr;g/g) and 50 ng/g of TGF&agr;. The panels are shown at higher magnification. In the top panel, the severely injured crypt surface from CP treatment shows cellular destruction due to necrosis. Red cells appear at the damaged surface to indicate intestinal bleeding. In addition, the middle panel of a CP-treated mouse shows a loss of brush border and very little of a glycocalyx or fuzzy coat. The interspersed globlet cells appear fewer in number (than normal) and are seen as necrotic. In the bottom panel, the effect of TGF&agr; treatment shows protection of the villa surface (arrows). Specifically, the epithelial cells are normal appearing with extended brush borders. The nuclei are very densely stained and elongated.

[0074] The histological data is summarized in FIG. 8 that measured average crypt height of the three groups of mice. TGF&agr; treatment (50 ng/g) was able to more-than-restore crypt height loss from CP treatment.

[0075] An alcian blue staining method permits differentiation of two major cell types that are an absorptive cell and a globlet cell. The globlet cell mucus is stained a greenish blue color while the absorptive cells remain less stained. In FIG. 9, the three panels at 160× magnification are shown to correspond to normal intestine in the top panel, CP only treated (10 &mgr;g/g) in the middle panel and both CP (10 &mgr;g/g) and TGF&agr; (50 ng/g) in the bottom panel. In the normal intestine (top panel), each villus extends from the luminal surface to the basal muscularis mucosal surface. Globlet cells are scattered and predominate in the base of the villus (arrows) whereas columnar absorptive cells line the luminal surface. In the middle panel, the alcian blue staining method shows that the villi contain a fewer number of globlet cells (than normal) (arrows). The injured absorptive and globlet cells are degenerating at the tip of the villi (arrows). Abundant secretory mucus material is stained in the luminal surface (arrows). In the bottom panel, there is an increased number of globlet cells scattered throughout the villi (arrows). The intestinal villi are in normal form with elongation. The majority of enterocytes are not alcian blue stained positive. The luminal plasma membranes of the villi (arrows) are well protected by TGF&agr; treatment. The number of globlet cells were counted on the average unit length of intestine. These data are shown in FIG. 10. TGF&agr; treatment not only increased the number of globlet cells but increased the number from CP treatment to a higher level than normal intestine.

[0076] Accordingly, these data show the effects of TGF&agr;, and the loop peptides from formula I, formula II and formula III having therapeutic activity to treat or prevent mucositis associated with cytotoxic therapy and for inflammatory bowel diseases. Moreover, the histological effect showing that there was a prevention of mast cell degranulation (FIG. 11), provides additional data supporting the gastrointestinal applications for TGF&agr;, and the loop peptide of formula I, formula II and formula III.

[0077] In addition, TGF&agr; stimulated the proliferation of select immune cells (particularly of the T cell lineage) after administration to mice after immune-suppression of CP administration. The stimulated immune cells were phenotypically identified as CD4 positive T cells and double null CD4 negative CD8 negative T cell progenitors with characteristics of NK-1 cells. Thus, TGF&agr; regulated immune functions and in particular defects in NK-1 cells. Therefore, these data predict that TGF&agr; and the loop peptide of formula I, formula II and formula III will be effective in treating autoimmune diseases by mitigating over-inflammatory reactions. The in vivo activity of TGF&agr; (FIG. 11) (and the loop peptide of formula I, formula II and formula III) to stimulate early T cell progenitors on the NK-1 type results in the release of TH-2 cytokines and this down regulates autoimmune phenomena. The stimulation of select immune cells, in particular cells of a T cell lineage, was seen consistently in the mice who received CP and TGF&agr; (FIG. 11 for GI tract) in lymphoid tissue, Peyers Patches and the spleen. Further, recruitment of help via CD4 cells in some cases boosts immune system function in general.

[0078] In FIG. 11, TGF&agr; administration prevented mast cell degranulation and subsequent histamine release. This is a parallel activity that is in addition to the gastrointestinal anti-inflammatory activity and prevention of mucositis of TGF&agr; (and the loop peptide of formula I, formula II and formula III) described herein.

Claims

1. A compound that acts as a TGF&agr; mimetic, comprising at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

2. The compound of claim 1 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

3. The compound of claim 1 wherein X1a is Val, X1b is Gly and X1c is Ala.

4. The compound of claim 2 wherein X2 is Tyr, and X3 is Arg.

5. The compound of claim 2 wherein the loop peptide is 13 amino acids in length, wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

6. A pharmaceutical composition comprising a loop peptide in a pharmaceutically acceptable carrier, wherein the loop peptide compound comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

7. The pharmaceutical composition of claim 6 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

8. The pharmaceutical composition of claim 6 wherein X1a is Val, X1b is Gly and X1c is Ala.

9. The pharmaceutical composition of claim 7 wherein X2 is Tyr, and X3 is Arg.

10. The pharmaceutical composition of claim 7 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

11. A method for treating a neurodegenerative disease with an pharmaceutically active loop peptide, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

12. The method for treating a neurodegenerative disease of claim 11 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

13. The method for treating a neurodegenerative disease of claim 11 wherein X1a is Val, X1b is Gly and X1c is Ala.

14. The method for treating a neurodegenerative disease of claim 12 wherein X2 is Tyr, and X3 is Arg.

15. The method for treating a neurodegenerative disease of claim 12 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

16. A method for treating a CNS disease or disorder, wherein the CNS disease or disorder is selected from the group consisting of CNS ischemia, spinal cord injury, MS, and retinal injury, comprising with an pharmaceutically active loop peptide, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

17. The method for treating a CNS disease or disorder of claim 16 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

18. The method for treating a CNS disease or disorder of claim 16 wherein X1a is Val, X1b is Gly and X1c is Ala.

19. The method for treating a CNS disease or disorder of claim 17 wherein X2 is Tyr, and X3 is Arg.

20. The method for treating a CNS disease or disorder of claim 17 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

21. A method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

22. The method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy of claim 21 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

23. The method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy of claim 21 wherein X1a is Val, X1b is Gly and X1c is Ala.

24. The method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy of claim 22 wherein X2 is Tyr, and X3 is Arg.

25. The method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy of claim 22 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

26. The method for augmenting hematopoiesis during cytotoxic or immune-suppressing therapy of claim 21 further comprising administering a second hematopoietic growth factor agent to stimulate more mature hematopoietic precursor cells, wherein the second hematopoietic growth factor is selected from the group consisting of erythropoietin, thrombopoietin, G-CSF (granulocyte colony stimulating factor), and GM-CSF (granulocyte macrophage colony stimulating factor).

27. A method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

28. The method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy of claim 27 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

29. The method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy of claim 27 wherein X1a is Val, X1b is Gly and X1c is Ala.

30. The method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy of claim 28 wherein X2 is Tyr, and X3 is Arg.

31. The method for treating or preventing mucositis of the gastrointestinal tract during cytotoxic or immune-suppressing therapy of claim 28 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

32. A bifunctional compound that acts as a TGF&agr; mimetic, comprising a compound from formula III:

Loop peptide N-terminus-linker-cyclic C4H8N2-linker-Loop peptide N-terminus  III

wherein the linker moiety is designed to link the N-terminus of the Loop peptide to a nitrogen atom of the ring C4H8N2 and wherein the “loop peptide” comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

33. The bifunctional compound that acts as a TGF&agr; mimetic of claim 32 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

34. The bifunctional compound that acts as a TGF&agr; mimetic of claim 32 wherein X1a is Val, X1b is Gly and X1c is Ala.

35. The bifunctional compound that acts as a TGF&agr; mimetic of claim 32 wherein the linker group is independently selected from the group consisting of substituted or unsubstituted C1-6 alkyl, substituted or unsubstituted C2-6 alkenyl, substituted or unsubstituted C1-6 alkoxy, xylenyl, wherein the substitutions are selected from the group consisting of oxo, epoxyl, hydroxyl, chloryl, bromyl, fluoryl, and amino.

36. The bifunctional compound that acts as a TGF&agr; mimetic of claim 33 wherein X2 is Tyr, and X3 is Arg.

37. The bifunctional compound that acts as a TGF&agr; mimetic of claim 33 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

38. A method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

39. The method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract of claim 38 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X413 X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

40. The method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract of claim 38 wherein X1a is Val, X1b is Gly and X1c is Ala.

41. The method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract of claim 39 wherein X2 is Tyr, and X3 is Arg.

42. The method for treating inflammatory bowel disease, colitis, and Chron's Disease of the gastrointestinal tract of claim 39 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.

43. A method for treating an inflammatory reaction of autoimmune diseases, comprising administering a TGF&agr; polypeptide or a pharmaceutically active loop peptide, or both, wherein the loop peptide comprises at least an 11-membered peptide compound from formula I:

N—X1a-Cys-His-Ser-X1b—X2—X1a—X1b—X1a—X3-Cys COOH  I

wherein X1 is independently Val, Gly or Ala, wherein X2 is Try or Phe, wherein X3 is Arg or Lys, and wherein the two Cys moieties form a disulfide bond to create an 11-amino acid loop peptide.

44. The method for treating an inflammatory reaction of autoimmune diseases of claim 43 wherein the autoimmune diseases are selected from the group consisting of Type II (Juvenile) Diabetes, rheumatoid arthritis, lupus, and multiple sclerosis.

45. The method for treating an inflammatory reaction of autoimmune diseases of claim 43 wherein at least one or more of the following seven amino acids are added to the C terminus Cys moiety from formula II:

—X4-His-X1c—X4—X5—X6—X1c  II

wherein X4 is Glu or Asp, wherein X5 is Leu or Ile, and wherein X6 is Asp or Glu.

46. The method for treating an inflammatory reaction of autoimmune diseases of claim 43 wherein X1a is Val, X1b is Gly and X1c is Ala.

47. The method for treating an inflammatory reaction of autoimmune diseases of claim 45 wherein X2 is Tyr, and X3 is Arg.

48. The method for treating an inflammatory reaction of autoimmune diseases of claim 45 wherein the loop peptide is 13 amino acids in length wherein X1a is Val, X1b is Gly, X1c is Ala, and X4 is Gly.