miR-34b 促进小鼠骨骼肌损伤后的再生功能和分子机制研究

During skeletal muscle regeneration after injury, skeletal muscle satellite cell is activated to divide, differentiate and fuse to repair myofiber. microRNAs (miRNAs) have emerged as key regulators in cell proliferation and differentiation. We observed that miR-34b is significantly up-regulated during muscle regeneration. An exogenous introduction of miR-34b promotes mouse myoblasts differentiation. Moreover, miR-34b downregulated a series of proteins involved in development and differentiation. We identified nucleolin as the potential target of miR-34b. In this proposal, the mechanism by which miR-34b controls cell proliferation and differentiation through nucleolin will be examined by miR-34b over-expression or inhibition; the effect of miR-34b on the regeneration of muscle fiber will be evaluated in mice. This project may not only reveal themechanism of miR-34b modulating muscle fiber development, but also show the therapeutic potential of miR-34b in muscle healing.

骨骼肌损伤以后再生的能力比较弱，往往因愈合时间长、局部瘢痕组织形成而影响最终愈合质量，甚至导致运动能力丧失。我们发现miR-34b具有促进骨骼肌修复的巨大潜力。miR-34b随骨骼肌损伤而表达上调；miR-34b显著性促进肌管形成；iTRAQ蛋白组学结果显示miR-34b可以下调肌细胞中一系列生长发育相关蛋白；结合靶基因预测分析，miR-34b可能靶向调控肌细胞修复的核仁素。推测，miR-34b调控成肌细胞的增殖/分化，促进骨骼肌损伤再生。本项目将在细胞水平上，解析miR-34b靶向核仁素促进分化的分子机制。此外，通过肌肉注射miR-34b，体内验证miR-34b调控骨骼肌再生的能力，明确miR-34b在肌肉损伤修复中的作用及其潜在的实际应用价值。本研究将首次揭示miR-34b促进肌肉再生修复功能，对如何有效提高损伤肌肉恢复的速度和质量提供一种新的治疗策略。

骨骼肌损伤以后再生的能力比较弱，往往因愈合时间长、局部瘢痕组织形成而影响最终愈合质量，甚至导致运动能力丧失。本项目发现miR-34b具有促进骨骼肌修复的巨大潜力。miR-34b随骨骼肌损伤而表达上调； miR-34b抑制肌细胞增殖而促进其分化；iTRAQ蛋白组学结果显示miR-34b可以下调肌细胞中一系列生长发育相关蛋白；结合靶基因预测以及细胞验证，miR-34b通过与3'UTR结合而靶向14-3-3蛋白γ，腺苷同型半胱氨酸酶和核仁素，miR-34b靶向NCL而抑制其蛋白表达；NCL显著促进肌细胞的增殖，细胞中核仁素的适度减少会增强肌管的形成；核仁素是肌发生所必需的，其沉默却阻碍肌管的形成，核仁素水平低的细胞会降低细胞增殖速率，细胞无法分化。进一步显示了miRNA微调在肌肉再生过程的重要性。本项目首次揭示miR-34b促进肌肉再生修复功能，对如何有效提高损伤肌肉恢复的速度和质量提供一种新的治疗策略。