Mechanosensitivity Box C/D small nucleolar RNA 90 promotes myogenic differentiation of skeletal muscle satellite cells
Objective To investigate the mechanism by which mechanical stimuli regulate the myogenic differentiation of skeletal muscle satellite cells via small nucleolar RNA(snoRNA).Methods Male C57BL/6 mice aged 8 weeks were purchased from Zhengzhou University Experimental Animal Center and randomly divided into two groups:a gravity-loaded group and a hindlimb unloaded group.A hindlimb suspension model was established to assess the impact of mechanical unloading on skeletal muscle.C2C12 cells were obtained from the Cell Bank of the Chinese Academy of Sciences.These cells were divided into two groups:a control group and a cyclic mechanical stretch group.The Flexcell FX-5000 Tension System was employed to construct a model of cyclic mechanical stretching stimulation on skeletal muscle satellite C2C12 cells.Gene expression changes in skeletal muscle tissue and C2C12 cells were detected by quantita-tive polymerase chain reaction(qPCR),and the expression of MRF4,MyoD,MyoG,and myocyte enhan-cer factor 2C(MEF2C)proteins in C2C12 cells was examined using Western blotting analysis.The binding of SNORD90 and miR-18a-3p was investigated using a dual-luciferase reporter gene assay.Statistical differences between the two groups were determined by Student's t-test,and P＜0.05 considered statisti-cally significant.Results The weight of the gastrocnemius muscle(0.165±0.015)and soleus muscle(0.141±0.021)in the HU group of mice was significantly lower than that in the WB group(0.221±0.013,t=9.574,P＜0.01;0.253±0.019,t=6.499,P＜0.01).Additionally,the expression of MEF2C mRNA in the gastrocnemius muscle of the HU group mice(0.462±0.274)was significantly lower than that of the WB group(1.000±0.137,t=9.606,P＜0.01).The expression of MEF2C mRNA in C2C12 cells of the CMS group(18.633±1.532)was significantly higher than that of the NC group(1.000±0.128,t=10.687,P＜0.01).Furthermore,the expression of MEF2C mRNA in C2C12 cells of the pLVX-SNORD90 group(1.748±0.122)was significantly higher than that of the pLVX-Vector group(1.000±0.128,t=9.684,P＜0.01).SNORD90 can bind miR-18a-3p through base pairing.Overex-pression of miR-18a-3p inhibited the expression of MEF2C protein,while suppression of miR-18a-3p expression promoted MEF2C protein expression,indicating that miR-18a-3p affects the regulatory role of SNORD90 on MEF2C protein expression.Conclusion Mechanical stimuli can promote the expression of SNORD90 in C2C12 cells.SNORD90 binds to miR-18a-3p through base-pair complementarity,inhibiting its function and promoting the expression of MEF2C.
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