The molecular mechanism of skeletal muscle autophagy in uremia:a study based on the FOXO3a/Nrf2 signaling pathway
Objective:To explore the role of the forkhead box O3a(FOXO3a)/nuclear factor erythroid 2-related factor 2(Nrf2)signal-ing pathway in regulating skeletal muscle autophagy in uremia.Methods:Twenty-four mice were randomly divided into sham group,chronic kidney disease(CKD)group,and CKD+AST-120(AST)group,with eight mice in each group.A CKD model was established by using the 5/6 nephrectomy method.Four weeks after nephrectomy,the mice in the CKD+AST group were fed with powder chow con-taining AST-120(a charcoal adsorbent for uremic toxin)for eight weeks.Autolysosomes in the gastrocnemius muscle were observed us-ing a transmission electron microscope.C2C12 myoblasts were divided into control group,indophenol sulfate group(IS),and IS+si-FOXO3a group.The expression of FOXO3a was determined using real-time RT-PCR and Western blot.The diameter of C2C12 myo-tubes was measured with Giemsa staining.Results:Compared with the CKD group,the CKD+AST group showed significant decreases in serum IS level and FOXO3a expression and the number of autolysosomes in the gastrocnemius tissue and significant increases in the masses of the gastrocnemius muscle,anterior tibial muscle,and soleus muscle(all P＜0.05).Compared with the IS group,the IS+si-FOXO3a group showed significant reductions in the expression of FOXO3a,atrogin-1,and muscle RING-finger protein-1 in C2C12 cells as well as the autophagic flux of the cells and a significantly increased cell diameter(all P＜0.05).Compared with the sham group,the CKD group showed significantly increased expression of Kelch-like ECH-associated protein 1(KEAP1)and significantly de-creased Nrf2 expression in the gastrocnemius tissue(both P＜0.05).AST treatment reversed the changes in these proteins in the gastroc-nemius tissue of CKD mice.Si-Nrf2 reversed the inhibitory effect of FOXO3a knockdown on autophagic flux.Conclusion:IS may pro-mote skeletal muscle autophagy by continuously stimulating the FOXO3A-KEAP1-Nrf2 axis to participate in the pathogenesis of uremic sarcopenia.
万方数据
维普
