卫星细胞是负责肌肉生长和再生的多潜能干细胞。卫星细胞增殖,分化,对成纤维细胞生长因子2(FGF2)的反应性,在某种程度上,由硫酸乙酰肝素蛋白聚糖syndecan-4和磷脂酰肌醇蛋白聚糖-1调节。Syndecan-4和磷脂酰肌醇蛋白聚糖-1表达随卫星细胞年龄而下降,可能与卫星细胞活性下降有关。本研究的目的是确定syndecan-4和磷脂酰肌醇蛋白聚糖-1的过表达是否会增加增殖,从16周龄火鸡的胸大肌中分离出的卫星细胞的分化和FGF2反应性。syndecan-4和磷脂酰肌醇蛋白聚糖-1的过表达在1d对增殖和分化没有显著影响,7周,和16周卫星细胞,并且在增殖过程中不影响FGF2反应性。syndecan-4和磷脂酰肌醇蛋白聚糖-1的表达在1d的48h增加了分化,7周,和用FGF2处理的16周细胞。成肌调节因子MyoD的表达,Myogenin,MRF4受syndecan-4和磷脂酰肌醇蛋白聚糖-1过表达的影响。然而,生肌调节因子表达的变化对增殖或分化没有显着影响。这些数据表明,syndecan-4和磷脂酰肌醇蛋白聚糖-1可能与卫星细胞活性的年龄相关降低没有直接关系。
Satellite cells are multipotential stem cells responsible for muscle growth and regeneration. Satellite cell proliferation, differentiation, and responsiveness to fibroblast growth factor 2 (FGF2) is, in part, regulated by the heparan sulfate proteoglycans syndecan-4 and glypican-1. Syndecan-4 and glypican-1 expression declines with satellite cell age and may be associated with decreased satellite cell activity. The objective of the current study was to determine if overexpression of syndecan-4 and glypican-1 would increase proliferation, differentiation and FGF2 responsiveness in satellite cells isolated from pectoralis major muscle from 16-wk-old turkeys. Overexpression of syndecan-4 and glypican-1 did not have a significant effect on proliferation and differentiation in 1d, 7 wk, and 16 wk satellite cells, and did not affect FGF2 responsiveness during proliferation. Expression of syndecan-4 and glypican-1 increased differentiation at 48 h in 1d, 7 wk, and 16 wk cells treated with FGF2. Expression of myogenic regulatory factors MyoD, myogenin, and MRF4 was affected by the overexpression of syndecan-4 and glypican-1. However, changes in myogenic regulatory factor expression did not have a significant effect on proliferation or differentiation. These data demonstrate that syndecan-4 and glypican-1 are likely not directly associated with the age related decrease in satellite cell activity.