College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Key Laboratory of Animal Nutrition and Feed Sciences, Ministry of Agriculture, Hangzhou, China.
Cell Mol Life Sci. 2022 Aug 12;79(9):481. doi: 10.1007/s00018-022-04474-0.
Although 5-methylcytosine (mC) has been identified as a novel and abundant mRNA modification and associated with energy metabolism, its regulation function in adipose tissue and skeletal muscle is still limited. This study aimed at investigating the effect of mRNA mC on adipogenesis and myogenesis using Jinhua pigs (J), Yorkshire pigs (Y) and their hybrids Yorkshire-Jinhua pigs (YJ). We found that Y grow faster than J and YJ, while fatness-related characteristics observed in Y were lower than those of J and YJ. Besides, total mRNA mC levels and expression rates of NSUN2 were higher both in backfat layer (BL) and longissimus dorsi muscle (LDM) of Y compared to J and YJ, suggesting that higher mRNA mC levels positively correlate with lower fat and higher muscle mass. RNA bisulfite sequencing profiling of mC revealed tissue-specific and dynamic features in pigs. Functionally, hyper-methylated mC-containing genes were enriched in pathways linked to impaired adipogenesis and enhanced myogenesis. In in vitro, mC inhibited lipid accumulation and promoted myogenic differentiation. Furthermore, YBX2 and SMO were identified as mC targets. Mechanistically, YBX2 and SMO mRNAs with mC modification were recognized and exported into the cytoplasm from the nucleus by ALYREF, thus leading to increased YBX2 and SMO protein expression and thereby inhibiting adipogenesis and promoting myogenesis, respectively. Our work uncovered the critical role of mRNA mC in regulating adipogenesis and myogenesis via ALYREF-mC-YBX2 and ALYREF-mC-SMO manners, providing a potential therapeutic target in the prevention and treatment of obesity, skeletal muscle dysfunction and metabolic disorder diseases.
虽然 5-甲基胞嘧啶（mC）已被鉴定为一种新型且丰富的 mRNA 修饰物，并与能量代谢有关，但它在脂肪组织和骨骼肌中的调节功能仍然有限。本研究旨在利用金华猪（J）、约克夏猪（Y）及其杂种约克夏-金华猪（YJ）研究 mRNA mC 对脂肪生成和肌生成的影响。我们发现 Y 比 J 和 YJ 生长得更快，而 Y 中观察到的与肥胖相关的特征低于 J 和 YJ。此外，与 J 和 YJ 相比，Y 的背脂层（BL）和背最长肌（LDM）中的总 mRNA mC 水平和 NSUN2 的表达率更高，这表明更高的 mRNA mC 水平与更低的脂肪和更高的肌肉量呈正相关。mC 的 RNA 亚硫酸氢盐测序分析显示了猪组织中特有的动态特征。功能上，富含 mC 的基因在与脂肪生成受损和肌生成增强相关的途径中富集。在体外，mC 抑制脂质积累并促进肌生成分化。此外，鉴定出 YBX2 和 SMO 是 mC 的靶基因。在机制上，具有 mC 修饰的 YBX2 和 SMO mRNA 被 ALYREF 识别并从细胞核输出到细胞质中，从而导致 YBX2 和 SMO 蛋白表达增加，从而分别抑制脂肪生成和促进肌生成。我们的工作揭示了 mRNA mC 通过 ALYREF-mC-YBX2 和 ALYREF-mC-SMO 方式在调节脂肪生成和肌生成中的关键作用，为肥胖、骨骼肌功能障碍和代谢紊乱疾病的预防和治疗提供了潜在的治疗靶点。
