Prosaposin expression in the regenerated muscles of mdx and cardiotoxin-treated mice
Prosaposin expression in the regenerated muscles of mdx and cardiotoxin-treated mice
复制标题
DOI：
10.14670/hh-28.875
复制
发表时间：
2013-07-01
影响因子：
2
通讯作者：
Matsuda, Seiji
中科院分区：
文献类型：
--
作者：
Li, Cheng;Gao, Hui-ling;Matsuda, Seiji
营养因子前塞塞蛋白 (PS) 在骨骼肌中强烈表达，据报道，PS 衍生肽可减轻体内神经损伤后肌肉质量的损失，并在体外增加成肌细胞与肌管的融合。然而，很少有研究关注 PS 在肌肉再生过程中的作用。我们使用免疫荧光染色、蛋白质印迹和原位杂交检查了正常、mdx 和心脏毒素 (CTX) 治疗小鼠骨骼肌中 PS 的表达。免疫荧光显示正常小鼠未损伤肌纤维和 CTX 注射后 8 周小鼠再生肌纤维的外周细胞质中存在强烈的 PS 免疫反应性。在接受 CTX 治疗的早期小鼠（14 天及更早）中，在浸润受损肌肉的免疫细胞中也检测到了强烈的 PS 免疫反应性，但其对肌纤维再生的作用较弱。蛋白质印迹证实了这些发现。相比之下，在免疫荧光和蛋白质印迹中，mdx 小鼠的 PS 持续较低。原位杂交证实了正常小鼠和 mdx 小鼠再生肌纤维中 PS mRNA 的减少，并揭示了 PS mRNA 的主要形式为 Pro+0，没有 9 碱基插入。胚胎肌球蛋白（MYH3）在 CTX 注射后 3、7 和 14 天以及 mdx 小鼠中明显定位于新再生的肌纤维中，但在再生肌纤维的后期（CTX 注射后 28 和 56 天）较低。 MYH3和PS的逆分布表明PS的表达与再生肌纤维的分化密切相关。对丝裂原激活蛋白 (MAP) 激酶信号通路的研究表明，磷酸化 ERK1/2 与肌纤维 PS 呈逆同步相关性，磷酸化 p-38 与肌纤维 PS 呈同步相关性。这些数据表明 PS 参与再生纤维肌肉分化的调节。
The trophic factor prosaposin (PS) is strongly expressed in skeletal muscle, and reportedly, a PS-derived peptide attenuates loss of muscle mass after nerve injury in vivo and increases myoblast fusion into myotubes in vitro. However, few studies have focused on the role of PS during muscle regeneration. We examined the expression of PS in the skeletal muscles in normal, mdx, and cardiotoxin (CTX)-treated mice using immunofluorescence staining, Western blotting, and in situ hybridisation. Immunofluorescence showed intense PS immunoreactivity in the peripheral cytoplasm of uninjured myofibres of normal mice and regenerated myofibres of 8 weeks post-CTX-injection mice. In early stage CTX-treated mice (14 days and earlier), intense PS immunoreactivity was also detected in the immune cells that infiltrated damaged muscle, but it was weak for regenerating myofibres. Western blot confirmed these findings. In contrast, PS was continuously low in mdx mice in both immunofluorescence and Western blotting. In situ hybridisation confirmed the decrease of PS mRNA in regenerated myofibres and revealed the main form of PS mRNA as Pro+0 without a 9-base insertion both in normal and mdx mice. The embryonic myosin (MYH3) was clearly localized in the newly regenerated myofibres at 3, 7, and 14 days of post-CTX-injection and mdx mice, but was lower in the late stage of regenerated myofibres (28 and 56 days post-CTX injection). The inverse distribution of MYH3 and PS indicates that the PS expression is closely related to the differentiation of regenerated myofibres. Investigation of the mitogen-activated protein (MAP) kinase signal pathway showed the inversely synchronous correlation of phosphorylated ERK1/2 with myofibre PS and the synchronous correlation of phosphorylated p-38 with myofibre PS. These data suggest that PS is involved in the regulation of muscle differentiation of regenerated fibres.