Recombinant Reg3α Prevents Islet β-Cell Apoptosis and Promotes β-Cell Regeneration (original) (raw)
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Recombinant Reg3β protein protects against streptozotocin-induced β-cell damage and diabetes
Scientific reports, 2016
Regenerating genes (Reg) have been found during the search for factors involved in pancreatic islet regeneration. Our recent study discovered that pancreatic β-cell-specific overexpression of Reg3β protects against streptozotocin (Stz) -induced diabetes in mice. To investigate its potential roles in the treatment of diabetes, we produced a recombinant Reg3β protein and provided evidence that it is active in promoting islet β-cell survival against Stz- triggered cell death. Though ineffective in alleviating preexisting diabetes, pretreatment of recombinant Reg3β was capable of minimizing the Stz-induced hyperglycemia and weight loss, by preserving serum and pancreatic insulin levels, and islet β-cell mass. No obvious changes were observed in the rate of cell proliferation and hypertrophy in α- or acinar-cells after treatment with recombinant Reg3β. The underlying mechanism of Reg3β-mediated protection seems to involve Akt activation which upregulates Bcl-2 and Bcl-xL levels and conse...
AJP: Endocrinology and Metabolism, 2011
Reg family proteins have been implicated in islet β-cell proliferation, survival, and regeneration. The expression of Reg3β (pancreatitis-associated protein) is highly induced in experimental diabetes and acute pancreatitis, but its precise role has not been established. Through knockout studies, this protein was shown to be mitogenic, antiapoptotic, and anti-inflammatory in the liver and pancreatic acinars. To test whether it can promote islet cell growth or survival against experimental damage, we developed β-cell-specific overexpression using rat insulin I promoter, evaluated the changes in normal islet function, gene expression profile, and the response to streptozotocin-induced diabetes. Significant and specific overexpression of Reg3β was achieved in the pancreatic islets of RIP-I/Reg3β mice, which exhibited normal islet histology, β-cell mass, and in vivo and in vitro insulin secretion in response to high glucose yet were slightly hyperglycemic and low in islet GLUT2 level. U...
Pancreatic beta-cell replication and amelioration of surgical diabetes by Reg protein
Proceedings of the National Academy of Sciences, 1994
We previously Isolated from a rat regeneratbig islet cDNA library a gene named Reg, which Is expressed in regenerating Islets but is not expressed in normal islets. Here we examined the effect of rat Reg protein on pancreatic beta-cell replication using both 90% depancreatized rats and isolated Islets. The depancreatized rats that received i.p. administration of recombinant rat Reg protein (1 mg/kg per day) for 2 months showed amelioration of the surgical diabetes, as evidenced by a sigificant decrease in blood glucose with an increased beta-cell mass in the residual pancreas. In Isolated rat Islets, Reg protein (18-180 nM: 0.3-3 pg/ml) significantly increased [3Hlthymidine incorporation into the nuclei of beta cells. These results indicate that Reg protein Is a growth factor for pancreatic beta cells and also suggest that the aministration of Reg protein could be used as another therapeutic approach for diabetes mellitus.
Journal of Biological Chemistry, 2000
Reg (regenerating gene) was isolated as a gene specifically expressed in regenerating islets (Terazono, K., Yamamoto, H., Takasawa, S., Shiga, K., Yonemura, Y., Tochino, Y., and Okamoto, H. (1988) J. Biol. Chem. 263, 2111-2114). Rat and human Reg gene products, Reg/REG proteins, have been demonstrated to stimulate islet -cell growth in vitro and in vivo and to ameliorate experimental diabetes. In the present study, we isolated a cDNA for the Reg protein receptor from a rat islet cDNA library. The cDNA encoded a cell surface 919-amino acid protein, and the cells into which the cDNA had been introduced bound Reg protein with high affinity. When the cDNA was introduced into RINm5F cells, a pancreatic -cell line that shows Reg-dependent growth, the transformants exhibited significant increases in the incorporation of 5-bromo-2-deoxyuridine as well as in the cell numbers in response to Reg protein. A homology search revealed that the cDNA is a homologue to a human multiple exostoses-like gene, the function of which has hitherto been unknown. These results strongly suggest that the receptor is encoded by the exostoses-like gene and mediates a growth signal of Reg protein for -cell regeneration.
Current Opinion in Endocrine and Metabolic Research, 2019
Type 3c diabetes mellitus (T3cDM) is a type of pancreatogenic diabetes. This form of diabetes has been significantly underappreciated, but is now receiving increased attention because of the recent recognition of its high incidence in chronic pancreatitis (CP) and other pancreatic diseases with irreparable loss of acinar cells. CP-associated T3cDM is characterized by insulin insufficiency resulting from pancreatic exocrine damage. However, how loss of acinar cells leads to insulin insufficiency in CP is practically unknown. Based on our review of the relevant literature and studies in our laboratory, we propose that lost protection from acinar cell-secreted regenerating proteins results in injury of the islet b cells in CP. Validation of this model may help in better understanding of the pathophysiology of T3cDM.
AJP: Gastrointestinal and Liver Physiology, 2010
Reg proteins are normally expressed in pancreatic acinar cells, and the level of several of these proteins was significantly induced upon damage to the endocrine or exocrine pancreas. It has been established that Reg1 and pancreatic islet neogenesis-associated protein [INGAP, Reg3δ] promote the growth or regeneration of the endocrine islet cells. Recent reports suggest that Reg2 is an autoantigen normally expressed in islet β-cells. Reg2 overexpression in vitro offered protection to insulinoma cells. Overexpressed Reg3α increased cyclin D1 and CDK4 levels and the rate of proliferation in insulinoma cells. Acinar-specific overexpression of INGAP increased β-cell mass and protected the animals from streptozotocin-induced diabetes. Moreover, Reg2 gene expression was induced during pancreatitis. We hypothesized that Reg2 is a secreted protein that promotes the growth, survival, and/or regeneration of pancreatic endocrine and exocrine cells. To test its effectiveness, we used elastase-1 ...
Endocrinology, 2001
We previously reported that new  cells differentiated in pancreatic islets of mice in which diabetes was produced by injection of a high dose of the  cell toxin streptozotocin (SZ), which produces hyperglycemia due to rapid and massive  cell death. After SZ-mediated elimination of existing  cells, a population of insulin containing cells reappeared in islets. However, the number of new  cells was small, and the animals remained severely hyperglycemic. In the present study, we tested whether restoration of normoglycemia by exogenous administered insulin would enhance  cell differentiation and maturation. We found that  cell regeneration improved in SZ-treated mice animals that rapidly attained normoglycemia following insulin administration because the number of  cells per islet reached near 40% of control values during the first week after restoration of normoglycemia. Two presumptive precursor cell types appeared in regenerating islets. One expressed the glucose transporter-2 (Glut-2), and the other cell type coexpressed insulin and somatostatin. These cells probably generated the monospecific cells containing insulin that repopulated the islets. We conclude that  cell neogenesis occurred in adult islets and that the outcome of this process was regulated by the insulin-mediated normalization of circulating blood glucose levels.
Existence of Islet Regenerating Factors within the Pancreas
The Review of Diabetic Studies, 2004
Reduction in the functional mass of β-cells is a common denominator in most forms of diabetes. Since the replicative potential of β-cells is limited, the search for factors that trigger islet neogenesis becomes imperative. Here we tested the hypothesis that regenerating factors for the pancreas are either secreted by or present within the pancreatic milieu itself. For this purpose, we intraperitoneally injected pancreatic cell culture supernatant (PCCS), from normal pancreas, into streptozotocin(STZ)-induced diabetic mice for 15 consecutive days. The PCCS-treated mice showed sustained reversal in 77.77% of experimental diabetic mice as evidenced by restoration of normoglycemia, increase in serum insulin levels and occurrence of neo islets in histopathological studies during a two month follow up, as opposed to the control diabetic mice which remained hyperglycemic throughout. In order to examine the potential of PCCS to bring about the regeneration of islets, we treated intra-islet precursor cells with PCCS in vitro, which led to the neogenesis of islets as evidenced by dithiozone and insulin immunostaining. These findings substantiate our hypothesis and make the search for regenerative factors converge towards the pancreas and its immediate surroundings. Such regenerative approaches, in combination with other therapeutic strategies to promote islet neogenesis may, in future, provide a cure and/or better means for the control and management of diabetes.
Diabetes, 2003
Reg (regenerating gene) was isolated as a gene specifically expressed in regenerating islets. We have demonstrated in vitro and in vivo that the exogenous addition of rat and human Reg gene products, Reg/REG proteins, induced -cell replication via the Reg receptor and thereby ameliorated experimental diabetes. In the present study, we produced Reg knockout mice by homologous recombination. The Reg gene disruption resulted in a null mutation. Knockout mice developed normally. Islets from the Reg knockout mice appeared morphologically indistinguishable from those of normal controls. However, [ 3 H]thymidine incorporation in isolated islets from Reg knockout mice was decreased. When hyperplastic islets were induced by the injection of goldthioglucose, the average islet size in Reg knockout mice was significantly smaller than that of control Reg ؉/؉ mice. We then produced transgenic mice carrying the Reg gene under the control of the rat insulin II promoter (Ins-Reg) to express Reg in -cells.