The Effect Of PSP/REG In PSC’ S Beta Cell Toxicity

Background & Objetive Progressive pancreatic fibrosis is a risk factor for diabetes in humans and rodents. Activated pancreatic stellate cells (PSC) involve in progression of islet fibrosis, which mediate destruction of functional β cell. Interestingly, pancreatic stone protein/regeneration protein (PSP/reg), a secretory protein produced in the exocrine pancreas, has been shown to ameliorate fibrosis due to its role in suppressing PSC activities. Yet the functional role of PSP-mediated PSC inhibition in β-cell function and survival remains to be elucidated. Our study aimed to examine whether PSP/reg alleviates PSC-mediated β-cell death and loss of function.Methods PSC isolated from ICR mice were cultured with or without PSP/reg for 24hours. Thereafter, supernatant was collected from treatment or control group termed as PSP-PSC-SN or PSC-SN respectively. For quantitative analysis of β-cell proliferation and apoptosis, MIN-6 cells were cultured with DMEM basic medium containing 1% BSA or PSP-PSC-SN or PSC-SN. Cells were harvested and subjected to either CCK-8 assay for cell proliferation or flow cytometry for cell death. Furthermore, culture media were gathered for insulin secretion analysis. Protein expression of P62 and LC3II/I were quantified by Western blot.Resultsa. Contrast to control group, stimulation of PSP/reg significantly increased MIN-6 cells proliferation, insulin secretion and autophage protein expressions However, no difference in cell apoptosis was observed between both experimental groups;b. MIN-6 cells cultured with PSC-SN supernatant displayed increased cell apoptosis, but reduced proliferative rate when compared to control group. Moreover, Treatment of PSC-SN conditioned medium led to decreased autophage protein expressions, which was associated with loss of insulin secretary function.c. MIN-6 cells harvested in SP-PSC-SN conditioned medium showed reduced cell apoptosis and autophage protein expressions relative to PSC-SN-treated group. Also, increased proliferative rate and insulin secretion was observed PSP-PSC-SN-treated MIN-6 cells when compared to cells stimulated with PSC-SN containing medium.d. In the PSC-SN culture condition, MIN-6 cells treated with PSP showed improved cell death and autophage protein expression, which was correlated with higher cell proliferation and insulin secretion regarding control groupConclusionTaken together, factors contained in PSC-SN supernatant inhibited MIN-6 cell proliferation and insulin secretion, hence promoted apoptosis and autophagy protein expression. Meanwhile, PSP/reg attenuated the detrimental effects of PSC on MIN-6 cells survival and function, which was revealed by, down-regulation of PSC-SN-mediated apoptosis, autophagocytosis and loss of insulin secretion. Thereafter, PSP/reg has a protective role in MIN-6 against PSC SN toxicity.