Takata Haruyuki, Terada Kumiko, Oka Hiroaki, Sunada Yoshihide, Moriguchi Takahiko, Nohno Tsutomu
Department of Plastic Surgery, Kawasaki Medical School, Kurashiki, Japan.
Dev Dyn. 2007 Oct;236(10):2800-7. doi: 10.1002/dvdy.21327.
The direct effects of Wnt4 on myogenic proliferation and differentiation of skeletal muscle precursors are examined. Wnt4 cDNA was misexpressed in the presumptive limb fields on the right side of stage 16 chick embryos. Muscle development was evaluated at stage 37 with hematoxylin-eosin staining and immunohistochemical staining for fast and slow types of the myosin heavy chain (MyHC). Overexpression of Wnt4 resulted in up-regulation of Pax7 and MyoD1 expression. The muscle mass showed a significant increase compared with that of the control limb. The area for fast MyHC-expressing cells showed a significant increase, whereas a slight decrease was observed for slow MyHC-expressing cells. Wnt4 acted as a stimulator during myogenic proliferation and differentiation, especially, for fast-type muscle in C2C12 cells. The present results are identical to those of myostatin knockout, suggesting that Wnt4 is acting against myostatin as an antagonizing signal for myostatin.
研究了Wnt4对骨骼肌前体细胞成肌增殖和分化的直接影响。在第16期鸡胚右侧的预定肢体区域中错误表达Wnt4 cDNA。在第37期用苏木精-伊红染色和针对快、慢型肌球蛋白重链（MyHC）的免疫组织化学染色评估肌肉发育。Wnt4的过表达导致Pax7和MyoD1表达上调。与对照肢体相比，肌肉质量显著增加。表达快肌MyHC的细胞面积显著增加，而表达慢肌MyHC的细胞则略有减少。Wnt4在成肌增殖和分化过程中起刺激作用，特别是对C2C12细胞中的快肌型肌肉。目前的结果与肌肉生长抑制素基因敲除的结果相同，表明Wnt4作为肌肉生长抑制素的拮抗信号与肌肉生长抑制素起相反作用。
