Zhang Kai, Chen Jianchao, He Haobin, Duan Binwei, You Canbei, Hu Zehua, Cai Linhao, Xiang Xi, Liang Rishen
College of Life Sciences and Oceanography Shenzhen University Shenzhen China.
College of Animal Science and Technology Zhongkai University of Agriculture and Engineering Guangzhou China.
Food Sci Nutr. 2025 May 13;13(5):e70268. doi: 10.1002/fsn3.70268. eCollection 2025 May.
Extrachromosomal circular DNAs (eccDNAs) play a significant role in regulating various biological processes, including abnormal muscle development. The molecular functions and impact of eccDNAs in the muscle development of fish are poorly understood. To investigate the potential roles of eccDNAs in the muscle development of fish, we analyzed and compared the expression profile of muscle eccDNAs of crisp grass carp, fed a faba bean meal-based diet, and ordinary grass carp, fed a practical diet. Using the Circle-seq strategy, we found the eccDNA abundance in crisp grass carp (211,920 eccDNAs) was significantly higher than that in ordinary grass carp (25,857 eccDNAs), suggesting that the faba bean diet likely independently influences eccDNA production. Compared to ordinary grass carp, crisp grass carp exhibited 10,565 upregulated and 129 downregulated eccDNAs, indicating eccDNAs were possibly associated with the muscle development of grass carp. GO and KEGG enrichment analyses indicated that the upregulated eccDNAs were related to muscle fiber development, cellular structure, and cell junctions. Based on our results, we speculated that the overexpression of genes involved in muscle fiber, calcium metabolism, and collagen driven by eccDNAs likely contributes to the observed increase in muscle fiber density, calcium levels, and collagen content in crisp grass carp, thereby enhancing muscle hardness. Notably, eccDNAs were identified as potential innate immunostimulants capable of eliciting immune responses in fish. In summary, our findings demonstrate that eccDNAs are aberrantly expressed in the muscles of fish fed a faba bean diet, offering novel insights into the molecular mechanisms underlying muscle hardening in fish.
染色体外环状DNA（eccDNA）在调节包括异常肌肉发育在内的各种生物学过程中发挥着重要作用。人们对eccDNA在鱼类肌肉发育中的分子功能和影响了解甚少。为了研究eccDNA在鱼类肌肉发育中的潜在作用，我们分析并比较了以蚕豆粉为基础日粮喂养的脆肉鲩和以实用日粮喂养的普通草鱼肌肉eccDNA的表达谱。使用Circle-seq策略，我们发现脆肉鲩中的eccDNA丰度（211,920个eccDNA）显著高于普通草鱼（25,857个eccDNA），这表明蚕豆日粮可能独立影响eccDNA的产生。与普通草鱼相比，脆肉鲩有10,565个eccDNA上调和129个eccDNA下调，表明eccDNA可能与草鱼的肌肉发育有关。GO和KEGG富集分析表明，上调的eccDNA与肌纤维发育、细胞结构和细胞连接有关。基于我们的结果，我们推测由eccDNA驱动的参与肌纤维、钙代谢和胶原蛋白的基因的过表达可能导致脆肉鲩中观察到的肌纤维密度、钙水平和胶原蛋白含量的增加，从而增强肌肉硬度。值得注意的是，eccDNA被鉴定为能够在鱼类中引发免疫反应的潜在先天免疫刺激剂。总之，我们的研究结果表明，eccDNA在以蚕豆日粮喂养的鱼类肌肉中异常表达，为鱼类肌肉硬化的分子机制提供了新的见解。
