High expression of miR-30c-5p in satellite cells of high-fat diet-induced obese rabbits inhibited satellite cell proliferation and promoted differentiation.

It was revealed in our previous study that the expression of miR-30c-5p in the skeletal muscle of rabbits fed high-fat diet was highly expressed. In the present study, we further investigated the function of miR-30c-5p in proliferation and differentiation of skeletal muscle satellite cell (SMSC). The results obtained in the present study showed that the skeletal muscle fibers of the rabbits fed the standard normal diet (SND) were orderly, regular, and uniform after HE staining, however, the muscle fibers of the rabbits fed the high-fat diet (HFD) were generally atrophied, some were arranged disorderly, the intercellular space was enlarged, the nucleus was increased, and the morphology and position were abnormal. Compared with the SND group, it was observed that the weekly weight gain and fat percentage were relatively higher, and also the levels of the serum biochemical indexes such as glucose, cholesterol, and triglyceride increased significantly in the rabbits fed with HFD. In addition, the results after the transfection of miR-30c-5p mimic, mimic NC (negative control), miR-30c-5p inhibitor, and inhibitor NC into the SMSCs showed that the cell counting kit-8 (CCK-8) proliferation experiment suggested that the number of cells in the over expression group was significantly lower than that in the mimic NC group at 48, 72, 96 h of cell proliferation. At 48, 72, 120 h, the number of cells in the inhibitor group was significantly higher than that in the mimic NC group. The number of EdU positive cells decreased significantly in the over expression group compared with the mimic NC group, however, it increased significantly in the inhibitor group compared with the inhibitor NC group. Moreover, compared with the mimic NC group, the myotube area increased significantly in the miR-30c-5p mimic group, whereas it decreased significantly in the miR-30c-5p inhibitor group as compared with the inhibitor NC group. In addition, we found that trinucleotide repeat containing adaptor 6A (TNRC6A) was successfully validated as a target gene for miR-30c-5p. The expression of TNRC6A in the miR-30c-5p mimic group was significantly lower than that in the mimic NC group. It was further observed that the expression of TNRC6A increased significantly in the miR-30c-5p inhibitor group as compared to that in the inhibitor NC group. Taken together, the results obtained in this study showed that miR-30c-5p promotes the differentiation as well as inhibits the proliferation of rabbit skeletal muscle satellite cells, and TNRC6A is a target gene of miR-30c-5p.

Genetic diversity of ATP8 and ATP6 genes is associated with high-altitude adaptation in yak.

ATP synthase 8 (ATP8) and ATPase synthase 6 (ATP6) play an important role in mitochondrial ATPase assembly. Mutations in either of these units could affect the ATP processing and the respiration chain in mitochondria. To find out if there were differences in gene diversity between Tibetan yaks and domestic cattle, we sequenced the ATP8 and ATP6 genes in 66 Tibetan yaks and 81 domestic cattle. We identified 20 SNPs in the ATP8 gene and 60 SNPs in the ATP6 gene. Ten SNPs detected in ATP8 were probably positively associated with high-altitude adaptation, of which SNPs m.8164 G > A, m.8210 G > A, m.8231 C > T and m. 8249 C > T resulted in amino acid changes. Similarly, SNPs m.8308A > G, m.8370A > C, m.8514G > A of ATP6 also appeared to be associated with high-altitude adaptability. Specifically, m.8308 A > G, located in the overlap region, might bring in a conserved region found in cytochrome b561 which play an important role in iron regulation, thus it might help the Tibetan yaks with this mutation to utilize rare oxygen efficiently. Considering all mutations, three of eight haplotypes identified in gene ATP8 were present only in Tibetan yaks, and six (H3 to H8) out of 21 haplotypes (H1 to H21) in gene ATP6 were restricted to Tibetan yaks. Haplotypes present only in Tibetan yaks could be positively associated with high-altitude adaptation.