PGC-1α differentially regulates the mRNA expression profiles of genes related to myofiber type specificity in chicken

Previous studies on mammals showed that peroxisome proliferator-activated receptor gamma coactivator-1α(PGC-1α)played a prominent role in regulating muscle fiber type transition and composition.However,the role of PGC-1αin chicken muscle has seldom been explored.To investigate the effect of PGC-1αon chicken skeletal muscles in this study,the PGC-1αgene was overexpressed or silenced in chicken primary myoblasts by using lentivirus,and then the effects of the PGC-1αgene overexpression and knockdown on the mRNA expression profile of genes related to myofiber type specificity were examined during fiber formation.The results showed that overexpression of PGC-1αfrom proliferation to differentiation was accompanied by the up-regulated expression of Pax7,MyoD,and CnAα,which was significantly(P<0.01)increased after one day of transfection(1 I).The enhancement of MyoG,MEF2 c,and MyHC SM expression lagged,which was improved significantly(P<0.01)after four days of transfection(1 I3 D).Overexpression of PGC-1αdecreased(P<0.01)the MyHC FWM expression after four days of transfection(1 I3 D),and it had no significant impact(P>0.05)on the expression of CnB1,NFATc3,and MyHC FRM during myofiber formation.The effective silence(P<0.01)of PGC-1αby lentivirus mediating short hairpin RNA(shRNA)was detected after four days of transfection(1 I3 D)in cultures,and the lack of its function in chicken primary myoblasts significantly(P<0.01)down-regulated the expression of Pax7,MyoD,CnAα,MyoG,MEF2 c,and MyHC SM,significantly(P<0.01)up-regulated the expression of MyHC FWM,and had no significant impact(P>0.05)on the expression of CnB1,NFATc3,and MyHC FRM.These results indicated that the role of PGC-1αin regulating the fiber type specificity of chicken skeletal muscles might be similar to that in mammals,which interplayed with key genes related to myocyte differentiation and calcineurin signaling pathway.

Use of transcriptome sequencing to explore the effect of CSRP3 on chicken myoblasts

The mechanisms that regulate the specificity and maintenance of chicken muscle fiber types remain largely unknown. In mammals, CSRP3 has been shown to play a vital role in the maintenance of typical muscle structure and function. This study investigated the role that CSRP3 plays in chicken skeletal muscle. First, the antibody against chicken CSRP3 protein was prepared, and the expression levels of the mRNA and protein of the CSRP3 gene in four chicken skeletal muscles with different myofiber compositions were compared. Then the effects of CSRP3 silencing on the expression profile of chicken myoblast transcriptomes were analyzed. The results showed that the expression levels of the mRNA and protein of the CSRP3 gene were both associated with the composition of fiber types in chicken skeletal muscles. A total of 650 genes with at least 1.5-fold differences(Q<0.05) were identified, of which 255 genes were upregulated and 395 genes were downregulated by CSRP3 silencing. Functional enrichment showed that several pathways, including adrenergic signaling in cardiomyocytes, adipocytokine signaling pathway and apelin signaling pathway, were significantly(P<0.05) enriched both in differentially expressed genes and all expressed genes. The co-expressed gene network suggested that CSRP3 silencing caused a compensatory upregulation(Q<0.05) of genes related to the assembly of myofibrils, muscle differentiation, and contraction. Meanwhile, two fast myosin heavy chain genes(MyH1B and MyH1E)were upregulated(Q<0.05) upon CSRP3 silencing. These results suggested that CSRP3 plays a crucial role in chicken myofiber composition, and affects the distribution of chicken myofiber types, probably by regulating the expression of MyH1B and MyH1E.