The Role Of Runx1 In Skeletal Muscle Atrophy And Injury Caused By Starvation And Ischemia-reperfusion Injury

Background: The role of Runx1 in denervation,cardiotoxin injury,and dystrophin deficiency model has been reported in the literature,but the role of Runx1 in muscle wasting and injury induced by starvation and ischemia-reperfusion remain unknowns.Objective: The aim of this study is to explore the role of Runx1 in skeletal muscle atrophy caused by starvation and ischemia-reperfusion.Methods:(1)To establish a starvation or ischemia-reperfusion muscle atrophy model in C57 mice,then extract RNA from mouse gastrocnemius muscle for microarray analysis.(2)The results of microarray were analyzed to identify the genes that are differentially regulated in starvation or ischemia-reperfusion,and then verified by Real-time PCR.(3)Overexpression or CRISPR/Cas9 knockout were performed in order to exam the effect of Runx1 on the proliferation and differentiation of C2C12 cells.(4)Satellite cells(SC)were isolated from C57 mouse tibialis anterior muscle..The cells were induced them to differentiate into myotubes by growing the cells in low concentrations of horse serum(2%)and the expression of Runx1 in undifferentiated and differentiated satellite cells were determined.(5)The role of Runx1 in skeletal muscle atrophy during starvation and ischemia reperfusion was determined based on literature review and experimental verification.Results: Microarray results showed that the expression of Runx1 increased significantly under both starvation and ischemia-reperfusion conditions,which was confirmed by Real-time PCR.Knockout of Runx1 by CRISPR/Cas9 inhibited C2C12 cells proliferation and differentiation,whereas overexpression of Runx1 promoted the differentiation and proliferation.The expression of Runx1 decreased in differentiated satellite cells.The difference of genes expression regulated by Runx1 under starvationand ischemia-reperfusion conditions were confirmed by Microarray analysis and Real-time PCR validation.Conclusion: Our study revealed Runx1 may compensate for skeletal muscle atrophy and injury by promoting satellite cell activation and keeping the balance of skeletal muscle cell proliferation and differentiation.It is also showed that Runx1 plays a promoting role in the formation and regeneration of myotubes.In addition,the expression of downstream target genes that are regulated by Runx1 differs in starvation and ischemia-reperfusion also been founded.