PLASMA FIBRONECTIN PROMOTES MODULATION OF ARTERIAL SMOOTH-MUSCLE CELLS FROM CONTRACTILE TO SYNTHETIC PHENOTYPE
PLASMA FIBRONECTIN PROMOTES MODULATION OF ARTERIAL SMOOTH-MUSCLE CELLS FROM CONTRACTILE TO SYNTHETIC PHENOTYPE
复制标题
DOI：
10.1111/j.1432-0436.1987.tb01563.x
复制
发表时间：
1987-01-01
期刊：
影响因子：
2.9
通讯作者：
THYBERG, J
中科院分区：
文献类型：
--
作者：
HEDIN, U;THYBERG, J
在含有全血血清或血浆衍生血清的培养基中培养的分离的动脉平滑肌细胞（SMC）经历从收缩表型到合成表型的调节。这个过程包括肌丝的丧失和收缩能力的停止。相反，形成了广泛的粗面内质网和大型高尔基复合体，如果受到刺激，细胞开始活跃增殖并产生细胞外基质成分。在体内，SMC分化特性的类似变化似乎是动脉粥样硬化形成的早期关键事件。本研究的目的是试图确定血浆成分，促进平滑肌表型的调制。酶法分离大鼠主动脉平滑肌细胞，在无血清培养基中培养，透射电镜观察细胞表型，3H-胸腺嘧啶核苷放射自显影和细胞计数观察细胞生长情况。在这些条件下，科恩组分I（纤维蛋白原）和V（白蛋白）被发现部分支持细胞附着和从收缩到合成表型的转变，而组分II-III和IV（球蛋白）在这方面是无活性的。明胶Sepharose 4B吸附柱分析表明Cohn级分I，而不是级分V，含有纤连蛋白，一种存在于血浆中并与纤维蛋白原结合的粘附蛋白。当接种在血浆纤连蛋白基质上时，细胞以高效率附着并以与含血清培养基中观察到的相似的速率调制成合成表型。在没有外源性有丝分裂原的情况下，细胞的结构转化并不伴随着增殖反应。然而，当暴露于血小板衍生生长因子或血清时，细胞迅速开始合成DNA并分裂。这些研究结果表明，血浆纤连蛋白是动脉SMC的表型特性的主要决定因素，他们证实了表型调制是必要的，但本身并不足以启动SMC生长的观点。这里概述的实验系统应该能够研究SMC表型和生长的控制分别在规定的条件下。
Isolated arterial smooth-muscle cells (SMCs) cultured in medium containing whole blood serum or plasma-derived serum undergo modulation from a contractile to a synthetic phenotype. This process includes the loss of myofilaments and cessation of the ability to contract. Instead, an extensive rough endoplasmic reticulum and a large Golgi complex are formed and, if property stimulated, the cells start to proliferate actively and to produce extracellular-matrix components. In vivo, a similar change in the differentiated properties of SMCs appears to be an early key event in atherogenesis. The purpose of the present investigation was to try to identify plasma components that promote the modulation of the smooth-muscle phenotype. SMCs were enzymatically isolated from rat aorta and cultured in a defined, serum-free medium.The phenotypic state of the cells was determined by transmission electron microscopy, and their growth status was followed by 3H-thymidine autoradiography and cell counting. Under these conditions, Cohn fractions I (fibrinogen) and V (albumin) were found to partially support cell attachment and transition from the contractile to the synthetic phenotype, whereas fractions II-III and IV (globulins) were inactive in this respect. Analysis on adsorptive columns of gelatin Sepharose 4B indicated Cohn fraction I, but not fraction V, contained fibronectin, an adhesive protein that is present in plasma and binds to fibrinogen. When seeded on a substrate of plasma fibronectin, the cells attached with high efficiency and modulated into the synthetic phenotype at a rate similar to that observed in serum-containing medium. In the absence of exogneous mitogens, the structural transformation of the cells was not accompanied by a proliferative response. However, when exposed to platelet-derived growth factor or serum, the cells promptly started to synthesize DNA and divide. These findings indicate that plasma fibronectin is a major determinant of the phenotypic properties of arterial SMCs, and they confirm the view that phenotypic modulation is necessary, but is itself not sufficient, for the initiation of SMC growth. The experimental system outlined here should make it possible to study the control of SMC phenotype and growth separately and under defined conditions.