The Role Of YB-1 In Regulating Islet β Cell Senescence In The Development Of Type 2 Diabetes

Objective:1 To explore the changes of the expression level of YB-1 in isletβcells during the progression of type 2 diabetes.2 To analyze the regulation of YB-1 in isletβcells on senescence and insulin secretion.Method:In vivo experiments,we choose C57BL/6J wild mice as the research objects,12 mice were randomly divided into two groups,and were given a high-fat diet or chow diet.After 3 months intervention,the high-fat diet group mice were built a successful type 2 diabetes model,which was confirmed by intraperitoneal injection of glucose tolerance test and intraperitoneal injections of insulin tolerance experiment.Then,compare the proportion of senescentβcells and expression of YB-1 in islets of high-fat diet group and chow diet group.In vitro experiments,MIN6 isletβcell line was used as the research object,and H2O2 was used as senescence inducer.First,MIN6 cells were treated with different concentrations of H2O2,and cell proliferation was investigated by CCK8 assay.Senescence was successfully induced by detecting the expression ofβ-gal and senescence related gene P16、P21and IGF1R,and the optimal senescence induced concentration of H2O2was determined.Meanwhile,the change of YB-1 expression was detected.Finally,By transfecting si-RNA and YB-1 plasmid to decrease or increase YB-1 expression in MIN6 cells,the expression of senescence-related genes P16,P21,IGF1R were detected by RT-QPCR assay and the senescence of cells was observed byβ-gal staining,and the insulin secretion ability of MIN6 cells was assessed by GSIS assay to resolve the effect of YB-1 in pancreaticβcells on isletβcell senescence and its insulin secretion function.Result:1 High-fat diet induced body weight gain,increased fasting blood glucose,and increased glucose area under the curve at each time point of IPGTT and IPITT test in type 2 diabetic mice.2 The proportion of senescentβcells in the islets of type 2 diabetic mice in the high-fat diet group increased and the expression of YB-1decreased;3 Compared with other concentrations,the expression of aging markers p16^Ink4a,p21^Cip1and IGF1R in MIN6 cells was the highest when450u M H2O2 was administered,and the proportion of senescence-relatedβ-gal positive cells was the highest.Moreover,at this concentration,no enhancement of cell proliferation caused by low concentration oxidative stress occurred.4 Decreased the expression of YB-1 in MIN6 cells,resulting in increased expression of senescence markers p16^Ink4a,p21^Cip1and IGF1R,increased the proportion of senescence-relatedβ-gal positive cells,and decreased the ability of glucose-stimulated insulin secretion;5 Increased expression of YB-1 in MIN6 cells resulted in decreased expression of senescence markers p16^Ink4a,p21^Cip1and IGF1R,decreased proportion of senescence-relatedβ-gal positive cells,and enhanced insulin secretion stimulated by glucose.Conclusion:1 High fat diet for 3 months can successfully construct the mouse model of type 2 diabetes.2 Type 2 diabetes can increase the proportion of senescentβcells and decrease the expression of YB-1 in the islets.3 Decreased the expression of YB-1 in MIN6 cells,making the cells more susceptible to senescence in the face of oxidative stress and weaken the insulin secretion ability.4 Increasing the expression of YB-1 in MIN6 cells can improve the anti-senescence ability of cells in the face of oxidative stress and enhance the insulin secretion ability.