Organism-wide contributions to systemic skeletal muscle repair in larval zebrafish.

We developed a systemic muscle injury model in zebrafish. Single cell transcriptomic analysis of muscle and non-muscle tissues revealed that systemic and local muscle injuries elicit distinct cellular molecular responses, both quantitatively and qualitatively. These studies suggest that large- and small-scale muscle injuries activate different regenerative programs, resulting in either systemic or local repair. To characterize the regenerative responses and signaling pathways activated after systemic or local muscle injury, we generated Tg(actc1b:NTR-mCherry) transgenic zebrafish lines.At 4 days post fertilization, transgenic larvae were treated with MTZ overnight to systemically injure all myofibers, or were subjected to local mechanical injury (needlestick) of 2-3 somites.Uninjured and systemically injured larvae were collected at 1, 2, and 4 days post injury. Mechanically injured larvae were collected at 2 days post injury. Sequencing results were compared between uninjured, systemically injured, and mechanically injured siblings.

本研究构建了斑马鱼全身性肌肉损伤模型。对肌肉及非肌肉组织开展单细胞转录组分析后发现，全身性与局部性肌肉损伤在细胞分子层面引发的应答反应存在显著差异，且该差异兼具定量与定性特征。上述研究表明，大规模与小规模肌肉损伤会激活不同的再生程序，最终分别引发全身性修复与局部性修复。为了表征全身性或局部性肌肉损伤后激活的再生应答与信号通路，我们构建了Tg(actc1b:NTR-mCherry)转基因斑马鱼品系。在受精后4天，将转基因幼体用MTZ处理过夜以实现所有肌纤维的全身性损伤，或对2~3个体节开展局部机械损伤（针刺法）。分别于损伤后1、2、4天收集未损伤及全身性损伤的幼体；于损伤后2天收集经机械损伤的幼体。对未损伤、全身性损伤及机械损伤的同窝幼体的测序结果进行对比分析。