Yu Zonggang, Wang Kaiming, Chen Bohe, Liu Jingwen, Chen Wenwu, Ma Haiming
College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Key Laboratory of Livestock and Poultry Resources (Pig) Evaluation and Utilization, Ministry of Agriculture and Rural Affairs, Changsha 410128, China.
Int J Mol Sci. 2025 Jun 28;26(13):6264. doi: 10.3390/ijms26136264.
Skeletal muscle is one of the largest tissues in the body. It is of great significance to analyze the molecular mechanism of skeletal muscle development for the further study of meat quality improvement and muscle diseases. CircRNA has been reported to be involved in many biological processes, but further research is needed in skeletal muscle. In this study, we detected the authenticity, stability, and spatio-temporal expression characteristics of circHOMER1 and its effect on the proliferation, apoptosis, and differentiation of muscle cells, and analyzed its possible molecular mechanism. The results showed that circHOMER1 exists in the skeletal muscle of the Ningxiang pig, is more stable than linear RNA, and is significantly upregulated in adipose tissue and during the early growth of myoblasts. In terms of function, overexpression of circHOMER1 significantly promoted the expression levels of proliferation marker genes and proteins and significantly increased the EdU positive cell rate, optical density (OD) value (at 450 nm), and proportion of S-phase cells. Overexpression of circHOMER1 also significantly promoted the expression levels of apoptosis marker genes and proteins and significantly increased the proportions of cells in Q2 (with late apoptosis) and Q3 (with early apoptosis). Overexpression of circHOMER1 significantly inhibited the expression levels of differentiation marker genes and proteins, significantly inhibited the differentiation index, and decreased the proportion of 5-nucleus muscle fibers. Conversely, opposite results were obtained after circHOMER1 interference. In terms of molecules mechanism, subcellular localization analysis showed that circHOMER1 was mainly distributed in cytoplasm, and mechanism analysis showed that circHOMER1 participated in myoblast development by forming a 4-element interaction network with 4 miRNAs, 2 lncRNAs, and 20 mRNAs, and possibly regulated myoblast development by encoding 79 amino acids. To sum up, we verified that circHOMER1 promoted the proliferation and apoptosis of myoblasts and inhibited their differentiation. It may regulate the development of myoblasts through ceRNA or by encoding small peptides. These results provided a reference for the regulation mechanism of muscle development and the breeding of Ningxiang pigs.
骨骼肌是人体最大的组织之一。分析骨骼肌发育的分子机制对于进一步研究肉质改善和肌肉疾病具有重要意义。据报道，环状RNA（circRNA）参与了许多生物学过程，但在骨骼肌方面仍需进一步研究。在本研究中，我们检测了circHOMER1的真实性、稳定性和时空表达特征及其对肌肉细胞增殖、凋亡和分化的影响，并分析了其可能的分子机制。结果表明，circHOMER1存在于宁乡猪的骨骼肌中，比线性RNA更稳定，在脂肪组织和成肌细胞早期生长过程中显著上调。在功能方面，circHOMER1的过表达显著促进了增殖标记基因和蛋白的表达水平，并显著提高了EdU阳性细胞率、光密度（OD）值（450nm处）和S期细胞比例。circHOMER1的过表达还显著促进了凋亡标记基因和蛋白的表达水平，并显著增加了Q2期（晚期凋亡）和Q3期（早期凋亡）细胞的比例。circHOMER1的过表达显著抑制了分化标记基因和蛋白的表达水平，显著抑制了分化指数，并降低了五核肌纤维的比例。相反，circHOMER1干扰后得到了相反的结果。在分子机制方面，亚细胞定位分析表明circHOMER1主要分布在细胞质中，机制分析表明circHOMER1通过与4个微小RNA（miRNA）、2个长链非编码RNA（lncRNA）和20个信使RNA（mRNA）形成四元相互作用网络参与成肌细胞发育，并可能通过编码79个氨基酸调节成肌细胞发育。综上所述，我们验证了circHOMER1促进成肌细胞增殖和凋亡并抑制其分化。它可能通过竞争性内源RNA（ceRNA）或通过编码小肽来调节成肌细胞的发育。这些结果为肌肉发育调控机制及宁乡猪的育种提供了参考。
