SWITCHING FROM DIFFERENTIATION TO GROWTH IN HEPATOCYTES - CONTROL BY EXTRACELLULAR-MATRIX
SWITCHING FROM DIFFERENTIATION TO GROWTH IN HEPATOCYTES - CONTROL BY EXTRACELLULAR-MATRIX
复制标题
DOI：
10.1002/jcp.1041510308
复制
发表时间：
1992-06-01
影响因子：
5.6
通讯作者：
INGBER, D
中科院分区：
文献类型：
--
作者：
MOONEY, D;HANSEN, L;INGBER, D
进行研究以分析不同细胞外基质（ECM）分子如何调节肝细胞生长和分化。将新鲜分离的大鼠肝细胞培养在非粘性塑料皿上，所述非粘性塑料皿预先涂覆有确定密度的层粘连蛋白、纤连蛋白、I型胶原或IV型胶原。使用稀疏的细胞铺板密度来最小化细胞-细胞接触形成，并且所有研究都在含有饱和量的可溶性生长因子的化学成分确定的培养基中进行。用低ECM密度（1 ng/cm 2）包被的培养皿支持肝细胞附着，但不促进细胞扩散或生长。计算机图像分析证实，在这些条件下，超过80%的细胞保持不与其他细胞接触。然而，这些圆形细胞保持高水平的白蛋白基因表达以及多种肝脏特异性蛋白（白蛋白，转铁蛋白和纤维蛋白原）的分泌速率升高，无论用于细胞附着的ECM分子的类型如何。当ECM涂层密度从1增加到1,000 ng/cm 2时，细胞铺展、组蛋白mRNA表达、DNA合成和细胞增殖均平行增加。高ECM密度对生长的激活也伴随着分化功能的伴随下调，并且再次，涂覆有所有四种类型ECM分子的培养皿产生类似的效果。因此，将肝细胞从分化转变为生长的能力（即，在不同的遗传程序之间）不限于单个ECM分子、不同的三维ECM几何形状或由于细胞-细胞相互作用的改变。相反，由固定的ECM分子传递的调节信号取决于它们存在的密度，因此取决于它们抑制或支持细胞扩散的能力。
Studies were carried out to analyze how different extracellular matrix (ECM) molecules regulate hepatocyte growth and differentiation. Freshly isolated rat hepatocytes were cultured on non-adhesive plastic dishes that were pre-coated with defined densities of either laminin, fibronectin, type I collagen, or type IV collagen. Sparse cell plating densities were used to minimize cell-cell contact formation and all studies were carried out in chemically defined medium that contained a saturating amount of soluble growth factors. Dishes coated with a low ECM density (1 ng/cm2) supported hepatocyte attachment, but did not promote cell spreading or growth. Computerized image analysis confirmed that over 80% of cells remained free of contact with other cells under these conditions. Yet, these round cells maintained high levels of albumin gene expression as well as elevated secretion rates for multiple liver-specific proteins (albumin, transferrin, and fibrinogen), regardless of the type of ECM molecule used for cell attachment. When ECM coating densities were raised from 1 to 1,000 ng/cm2, cell spreading, expression of histone mRNA, DNA synthesis, and cell proliferation all increased in parallel. Activation of growth by high ECM densities was also accompanied by a concomitant down-regulation of differentiated functions and again, dishes coated with all four types of ECM molecules produced similar effects. Thus, the ability to switch hepatocytes from differentiation to growth (i.e., between different genetic programs) is not limited to a single ECM molecule, a distinct three dimensional ECM geometry, or due to alteration of cell-cell interactions. Rather, the regulatory signals conveyed by immobilized ECM molecules depend on the density at which they are presented and thus, on their ability to either prohibit or support cell spreading.