The Research On The Function Of Reg1cp Mutation In Islet β Cell And Insulin Resistance

Objective:In our previous study,we identified a novel rs3819316 C > T mutation in lnc RNA Reg1 cp which is mainly expressed in human pancreas,especially in islet.Our study aims to clarify the effects of the mutated Reg1 cp on glucose metabolism in vivo and in vitro,and to analyze the mechanism of its regulation of pancreatic β cell function and insulin resistance,so as to provide a new target for early screening and treatment of type 2 diabetes.Methods:1.Population data were analyzed to understand the association between Reg1 cp mutation and the risk of type 2 diabetes;2.We constructed the islet β cell specific wild-type/mutant knock-in mice to understand the effects of Reg1 cp mutation on the function of isletβ cells and insulin resistance in mice;3.We conducted mass spectrometry assay of proteins after RNA pull-down to demonstrate which protein Mut-Reg1 cp directly binds to,in order to clarify the mechanism of Reg1 cp mutation regulation of islet βcell function and insulin resistance,immunofluorescence staining,western blot analysis,q PCR analysis and glucose stimulate insulin secretion test,and so on,were conducted.Results:1.Analyses in 16,113 Chinese adults revealed that Mut-Reg1 cp individuals have higher risk of T2 DM and present impaired insulin secretion as well as increased insulin resistance;2.Mice with islet β cell specific Mut-Reg1 cp knock-in have more severe islet β cell dysfuction and insulin resistance;3.Mass spectrometry assay of proteins after RNA pull-down demonstrated that Mut-Reg1 cp directly binds to Polypyrimidine Tract Binding Protein 1(PTBP1),futher immunofluorescence staining,western blot analysis,q PCR analysis and glucose stimulated insulin secretion test revealed that Mut-Reg1 cp disrupts the stabilization of insulin m RNA by inhibiting the phosphorylation of PTBP1 in islet β cells;4.Islet derived exosomes transfer Mut-Reg1 cp into peripheral tissues,which then promotes insulin resistance by inhibiting Adipo R1 translation and adiponectin signaling.Conclusion:Our findings identified a novel mutation in lnc RNA Reg1 cp which is involved in the pathogenesis of T2 DM,and revealed a new mechanism for islet β cell dysfunction and insulin resistance.