Sidt2 Deficiency Impact Autophagy And Causes A Myopathy

Objective: To further study the function of Sidt2 in skeletal muscle by constructing Sidt2 knockout mouse model,and observe the pathological changes in Sidt2 deficiency mouse model,then try to clarify the pathogenesis of myopathy in Sidt2 deficiency mouse model.Methods: Constructed Sidt2 knockout mouse model based on Cre-loxp system,and observed the ultrastructure and pathological changes by electron microscopy,HE staining,PAS staining,COX staining and immunofluorescence of Laminin.Then detected the express of autophagy-related-proteins normally or after starvation 24 hours by Western blot and immunofluorescence,meanwhile the level of apoptosis was detected by western blot and TUNEL assay.Results: The mouse models of sidt2 gene delete were successfully constructed,and were determined on DNA,RNA and protein level.In sidt2 knockout mouse skeletal muscle we can found: disordered structure of fibers,accumulated mitochondria,autophagic vacuole and chromosome aggregation or migrate to nuclear membrane by electron microscopy;muscle fibers atrophy,inflammatory infiltrates and degeneration by HE staining;abnormal sarcolemma and growing new muscle fibers by immunofluorescence of Laminin;a huge mass of glycogen accumulation by PAS staining;cytochrome oxidase was significantly reduce by COX staining.Analyzed the express of autophagy-related-proteins by western blot we can found in Sidt2 knockout mouse skeletal muscle LC3 II,P62,Beclin1,Atg5,Atg12 were increased,phospho-Akt,phospho-m TOR,phospho-S6K1 were decreased,Foxo3,phospho-Foxo3 were unchanged.P62 was accumulated in fibers detected by immunofluorescence.And after starvation 24 hours the express of autophagy-related-proteins were not changed control with normal feeding in sidt2 knockout mouse skeletal muscle.In addition the express of activated-Caspase3?activated-Caspase9?activated-Caspase12?Chop?Bip?phospho-e IF2a?phospho-perk?ATF6?Bax?Bad were increased.And apoptosis also increased by TUNEL method.Conclusion: Sidt2 knockout mouse develop myopathy related to impaired autophagy andapoptosis,on the one hand lacking of Sidt2 damage the degradation of autophagy and also blocked the induction of starvation-dependent autophagy,on the other hand Sidt2 knockout activate the endoplasmic reticulum stress and mitochondrial apoptosis pathway.