Expression of laminin α3, α4, and α5 chains by alveolar epithelial cells and fibroblasts
Expression of laminin α3, α4, and α5 chains by alveolar epithelial cells and fibroblasts
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DOI：
10.1165/ajrcmb.19.2.3087
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发表时间：
1998-08-01
影响因子：
6.4
通讯作者：
Senior, RM
中科院分区：
文献类型：
--
作者：
Pierce, RA;Griffin, GL;Senior, RM
层粘连蛋白是基底膜的主要成分。已知有11种层粘连蛋白同种型，每种都是由多肽链组成的异源三聚体，命名为α、β和γ。迄今为止已经鉴定出五种α链：α（1）、α（2）、α（3）、α（4）和α（5）。最近对胎儿和成年小鼠肺的研究表明，肺泡组织中α（3）、α（4）和α（5）的突出，并指出这些α链在发育中的肺泡中的细胞表达存在差异。我们检测了分离的大鼠肺泡II型细胞和肺成纤维细胞中flaminins α（3）、α（4）和α（5）的表达。我们发现层粘连蛋白α 3仅由肺泡上皮细胞表达，层粘连蛋白α 4仅由肺成纤维细胞表达，层粘连蛋白α 5主要由肺泡上皮细胞表达。代谢标记和免疫沉淀证实了层粘连蛋白α（4）由成纤维细胞产生，层粘连蛋白α（5）由培养的肺泡上皮细胞产生。这些研究表明，不同的肺泡细胞类型贡献不同的层粘连蛋白α链的层粘连蛋白亚型在肺泡基底膜。免疫组化显示这些层粘连蛋白a链与层粘连蛋白β（1）、β（2）和γ（1）链共定位，表明层粘连蛋白6至11可能存在于肺泡基底膜中。
Laminins are principal components of basement membranes. Eleven laminin isoforms an known, each a heterotrimer composed of polypeptide chains designated alpha, beta, and gamma. Five alpha chains have been identified to date: alpha(1), alpha(2), alpha(3), alpha(4), and alpha(5). Recent studies of fetal and adult mouse lung show prominence of alpha(3), alpha(4), and alpha(5) in alveolar tissue, and point to differences in the cellular expression of these alpha chains in the developing alveolus. We examined isolated rat alveolar type II cells and lung fibroblasts for expression oflaminins alpha(3), alpha(4), and alpha(5). We found that laminin alpha(3) was expressed only by alveolar epithelial cells, that laminin alpha(4) was expressed only by lung fibroblasts, and that laminin alpha(5) was expressed primarily by alveolar epithelial cells. Metabolic labeling and immunoprecipitation confirmed the production of laminin alpha(4) by fibroblasts and laminin alpha(5) by alveolar epithelial cells in culture. These studies indicate that different alveolar cell types contribute different laminin alpha chains to the laminin isoforms in alveolar basement membranes. Immunohistochemistry showed colocalization of these laminin a chains with the laminin beta(1), beta(2), and gamma(1) chains, indicating the likelihood that laminins 6 to 11 an present in alveolar basement membranes.