Nguyen Nguyet M, Bai Yushi, Mochitate Katsumi, Senior Robert M
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Am J Physiol Lung Cell Mol Physiol. 2002 May;282(5):L1004-11. doi: 10.1152/ajplung.00379.2001.
Basement membranes have a critical role in alveolar structure and function. Alveolar type II cells make basement membrane constituents, including laminin, but relatively little is known about the production of basement membrane proteins by murine alveolar type II cells and a convenient system is not available to study basement membrane production by murine alveolar type II cells. To facilitate study of basement membrane production, with particular focus on laminin chains, we examined transformed murine distal respiratory epithelial cells (MLE-15), which have many structural and biochemical features of alveolar type II cells. We found that MLE-15 cells produce laminin-alpha5, a trace amount of laminin-alpha3, laminins-beta1 and -gamma1, type IV collagen, and perlecan. Transforming growth factor-beta1 significantly induces expression of laminin-alpha1. When grown on a fibroblast-embedded collagen gel, MLE-15 cells assemble a basement membrane-like layer containing laminin-alpha5. These findings indicate that MLE-15 cells will be useful in modeling basement membrane production and assembly by alveolar type II cells.
基底膜在肺泡结构和功能中起关键作用。肺泡II型细胞可产生包括层粘连蛋白在内的基底膜成分，但对于小鼠肺泡II型细胞产生基底膜蛋白的情况了解相对较少，且尚无便捷系统用于研究小鼠肺泡II型细胞的基底膜生成。为便于研究基底膜生成，特别是聚焦于层粘连蛋白链，我们检测了转化的小鼠远端呼吸道上皮细胞（MLE-15），其具有许多肺泡II型细胞的结构和生化特征。我们发现MLE-15细胞可产生层粘连蛋白α5、微量的层粘连蛋白α3、层粘连蛋白β1和γ1、IV型胶原以及基底膜聚糖。转化生长因子β1可显著诱导层粘连蛋白α1的表达。当在包埋有成纤维细胞的胶原凝胶上生长时，MLE-15细胞可组装出含有层粘连蛋白α5的类似基底膜的层。这些发现表明，MLE-15细胞将有助于模拟肺泡II型细胞的基底膜生成和组装。
