Simonson M S, Culp L A, Dunn M J
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
Exp Cell Res. 1989 Oct;184(2):484-98. doi: 10.1016/0014-4827(89)90346-7.
The glomerular mesangium contains fibronectin (FN), laminin, and collagen IV, but it remains unclear whether these matrix proteins affect mesangial cellular functions. The present experiments were designed to test whether cell-matrix interactions could affect some functions of mesangial cells. Cultured rat mesangial cells synthesized a cellular form of FN that was both secreted and incorporated into an extensive, fibrillar pericellular matrix. This FN matrix was increased in high-density cultures and was more developed in human mesangial cells. Rat mesangial cells in vitro displayed a marked capacity to incorporate exogenous FN into a pericellular matrix, demonstrating that accumulations of FN in the mesangial matrix could result from endogenous and/or exogenous sources. Rat mesangial cells also expressed RGD-sensitive integrin receptors for FN, laminin, and collagens I and IV that promoted cell adhesion and that directed differential changes in morphology. Indirect evidence suggested the existence of other mesangial binding sites for extracellular matrix proteins. FN and collagen IV also stimulated modest increases in [3H]thymidine uptake and cell number by quiescent cells. Taken together, these results suggest that cultured mesangial cells present a model system for studying the regulation of cell-matrix interactions in the mesangium.
肾小球系膜含有纤连蛋白（FN）、层粘连蛋白和IV型胶原，但这些基质蛋白是否影响系膜细胞功能仍不清楚。本实验旨在测试细胞与基质的相互作用是否会影响系膜细胞的某些功能。培养的大鼠系膜细胞合成了一种细胞形式的FN，它既被分泌又整合到广泛的纤维状细胞周围基质中。这种FN基质在高密度培养中增加，在人系膜细胞中更发达。体外培养的大鼠系膜细胞表现出将外源性FN整合到细胞周围基质中的显著能力，表明系膜基质中FN的积累可能源于内源性和/或外源性来源。大鼠系膜细胞还表达了对FN、层粘连蛋白以及I型和IV型胶原敏感的RGD整合素受体，这些受体促进细胞黏附并引导形态学的差异变化。间接证据表明存在其他细胞外基质蛋白的系膜结合位点。FN和IV型胶原还能适度刺激静止细胞的[3H]胸腺嘧啶核苷摄取和细胞数量增加。综上所述，这些结果表明培养的系膜细胞为研究系膜中细胞与基质相互作用的调节提供了一个模型系统。
