Cossu G, Cicinelli P, Fieri C, Coletta M, Molinaro M
Exp Cell Res. 1985 Oct;160(2):403-11. doi: 10.1016/0014-4827(85)90187-9.
Human satellite cells, obtained by surgical biopsies of traumatized legs of healthy individuals, were grown in culture in the presence of different concentrations of the phorbol ester tetradecanoyl-phorbol 12 acetate (TPA). Satellite cells, after an initial duplicative period, fused into large multinucleated myotubes which readily synthesized myosin and acetylcholine receptor (AChR). The presence of TPA at concentrations up to 10(-7) M did not affect the differentiation pattern, while higher concentrations were toxic. Thus human satellite cells are capable of differentiating in the presence of phorbol esters which block differentiation of embryonic myoblasts [1]. We then examined the appearance of TPA-resistant cells during human muscle histogenesis, since we had observed that differentiation of human myoblasts from a 6-week-old limb was completely and reversibly inhibited by 10(-7) M TPA. Differentiation of myoblasts from 6-, 7- and 8-week-old fetuses was completely inhibited by TPA. Myoblasts from 10-week-old limbs did not form myotubes in the presence of TPA; however, immunohistochemical staining with an antimyosin antibody revealed the presence of a few mononucleated myosin-positive cells which escaped the TPA-induced block of differentiation. At 12 weeks of development, a few oligonucleated, myosin-positive myotubes developed in cultures treated with TPA, and the level of AChR expressed (measured as [125I] alpha-bungarotoxin bound) reached 20% of controls. At 14 weeks of development, about half of the cells in culture were TPA-resistant and by 16 weeks of development no major differences could be detected between control and treated cells. We conclude from these data that a population of TPA-resistant myogenic cells emerges between the 10th and 14th week of human limb development and suggest that this population represents satellite cells.
从健康个体受伤腿部的手术活检中获取人类卫星细胞，将其置于含有不同浓度佛波酯十四烷酰佛波醇12 - 乙酸酯（TPA）的培养基中培养。卫星细胞在经历初始增殖期后，融合形成大型多核肌管，这些肌管易于合成肌球蛋白和乙酰胆碱受体（AChR）。浓度高达10⁻⁷ M的TPA的存在并不影响分化模式，而更高浓度则具有毒性。因此，人类卫星细胞能够在佛波酯存在的情况下分化，而佛波酯会阻断胚胎成肌细胞的分化[1]。然后，我们研究了人类肌肉组织发生过程中对TPA耐药细胞的出现情况，因为我们观察到，来自6周龄肢体的人类成肌细胞的分化会被10⁻⁷ M TPA完全且可逆地抑制。来自6、7和8周龄胎儿的成肌细胞的分化被TPA完全抑制。来自10周龄肢体的成肌细胞在TPA存在的情况下不形成肌管；然而，用抗肌球蛋白抗体进行免疫组织化学染色显示存在一些单核的肌球蛋白阳性细胞，这些细胞逃脱了TPA诱导的分化阻滞。在发育12周时，在用TPA处理的培养物中形成了一些含少量核的、肌球蛋白阳性的肌管，并且所表达的AChR水平（以结合的[¹²⁵I]α - 银环蛇毒素测量）达到对照的20%。在发育14周时，培养物中约一半的细胞对TPA耐药，到发育16周时，对照细胞和处理细胞之间未检测到主要差异。从这些数据我们得出结论，在人类肢体发育的第10周和第14周之间出现了一群对TPA耐药的生肌细胞，并表明这群细胞代表卫星细胞。
