Akirin2对猪骨骼肌生长和肌纤维类型组成的调节作用及其机理研究

Based on the hypothesis that Akirin2 participates in the regulation of skeletal muscle growth and muscle fiber types composition of pigs, the expression patterns of porcine Akirin2 and related genes in skeletal muscle growth and muscle fiber types during porcine skeletal muscle development will be examined, as well as the correlations among them will also be analyzed. On this basis, in this project porcine Akirin2 gene overexpression and active immunization against porcine Akirin2 technologies were employed to elucidate whether Akirin2 participates in the skeletal muscle growth and muscle fiber types composition of pigs. Moreover, to reveal the mechanism of Akirin2 modulating the skeletal muscle growth and muscle fiber types composition, porcine Akirin2 gene overexpression, exogenous addition of recombinant porcine Akirin2 protein and siRNA-mediated RNA interference technologies were employed to elucidate whether Akirin2 regulates the myogenic differentiation of porcine satellite cells and muscle fiber types composition of porcine myotubes. The present project may not only shed new light on the mechanisms involved in the control of skeletal muscle growth and muscle fiber type composition of pigs, but also allow for developing new approaches for improving lean meat percentage of pigs and the quality of pork.

基于"Akirin2参与调节猪骨骼肌生长及肌纤维类型组成"的科学假设，本项目在检测猪骨骼肌发育过程中猪Akirin2、骨骼肌生长和肌纤维类型相关基因的表达规律及分析它们之间相关性的基础上，拟采用过表达猪Akirin2和猪Akirin2主动免疫，以断奶仔猪为对象，阐明Akirin2对猪骨骼肌生长和肌纤维类型组成的影响，此外，拟采用过表达猪Akirin2、外源添加重组猪Akirin2蛋白和RNA干扰抑制猪Akirin2表达，考察其对猪骨骼肌卫星细胞成肌分化和肌管肌纤维类型组成的影响，探讨Akirin2调节猪骨骼肌生长和肌纤维类型组成的机理。开展本项目研究，不仅可以揭示猪骨骼肌生长发育和肌纤维类型组成的调节机制，也可以为寻求提高猪瘦肉率及改善猪肉品质提供新的思路。

本项目成功制备了猪Akirin2多克隆抗体。分析不同日龄DLY猪背最长肌中Akirin2、肌肉发育和肌纤维类型相关基因表达规律后发现，Akirin2与骨骼肌生长和肌纤维类型相关。动物试验结果表明，过表达猪Akirin2或重组猪Akirin2蛋白主动免疫均促进慢肌纤维相关基因的表达，抑制快肌纤维相关基因的表达，且该影响可能受CaN/NFATc1信号通路介导。项目还成功分离了猪骨骼肌卫星细胞，通过过表达猪Akirin2和RNA干扰猪Akirin2表达从正反两方面证实了Akirin2可促进猪骨骼肌卫星细胞增殖分化和猪慢性肌纤维的表达。采用信号通路特异性抑制剂，项目证实了Akirin2通过ERK1/2和CaN/NFATc1两条信号通路促进猪骨骼肌卫星细胞的增殖和分化，且ERK1/2和CaN/NFATc1信号通路之间存在相互作用。采用信号通路特异性抑制剂，项目还证实了Akirin2通过CaN/NFATc1信号通路促进猪慢型肌纤维的表达。上述体内外研究结果表明，Akirin2通过CaN/NFATc1信号通路促进猪骨骼肌生长和慢型肌纤维表达。项目研究结果不仅揭示了猪骨骼肌生长发育和肌纤维类型组成的调节机制，也为寻求提高猪瘦肉率及改善猪肉品质提供了新的思路。