Effects of Extracellular Matrix on Adopose Conversion

提出了一种小鼠前脂肪细胞在完全无血清的情况下成功培养并转化为成熟脂肪细胞的方法。ST13前脂肪细胞在RPMI1640和HAMF12中1：1的混合物中添加亚硒酸钠、HEPES、转铁蛋白、胰岛素、凝血酶和胎球蛋白，在包括4种胶原、纤维连接蛋白和层粘连蛋白的不同底物上进行培养。高效成脂剂3-羟基环格列酮(ADD)对无血清培养的ST-13细胞脂肪转化具有重要的诱导作用。就像补充血清的培养液中的细胞一样，ADD处理必须在对数生长期开始，以诱导有效的脂肪转化。然而，在无血清和添加血清的脂肪转化系统之间观察到两个主要的差异。首先，无血清培养的ST-13细胞需要胶原性基质(尤其是IV型胶原)来转化脂肪和维持融合的单层，而不是为了细胞增殖。其次，胰岛素在有血清补充系统中的作用相对较小，在无血清系统中是绝对需要的。目前的观察结果表明，在无血清条件下，rhat ST 13细胞紧密地保持在脂肪前状态，适当的成脂刺激(如ADD加胰岛素)对于脂肪转化是必不可少的。该无血清系统将有助于识别和研究影响脂肪转化的调节因素。

A method is presented by which murine preadipose cells may be successfully grown and converted into mature adipocytes in the complete absence of serum. ST 13 preadipocyte were grown in a 1 : 1 mixture of RPMI 1640 and Ham F12 supplemented with sodium selenite, Hepes, transferrin, insulin, thrombin, and fetuin on various substrates, including four types of collagen, fibronectin, and laminin. A highly potent adipogenic agent, 3-hydroxyciglitazone (ADD), was essential for the induction of adipose conversion of ST 13 cells grown under serum-free conditions. As was true for cells in serum-supplemented medium, ADD treatment must begin in the logarithmic growth phase to induce efficient adipose conversion. Two major differences were observed, however, between serum-free and serum-supplemented adipose conversion systems. First, ST 13 cells grown without serum require a collagenous substrate (especially collagen type IV) for adipose conversion and for maintenance of a confluent monolayer, through not for cell proliferation. Second, insulin, which plays relatively minor role in the serum-supplemented system, is required absolutely in the serum-free system. The present observation demonstrates rhat ST 13 cells are tightly held in the preadipose state under serum-free conditions and appropriate adipogenic stimuli (such as ADD plus insulin) are essential for adipose conversion. The serum-free system will be useful for the identification and investigation of regulatory factors affecting adipose conversion.