期刊
AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY
卷 285, 期 3, 页码 L593-L601出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajplung.00037.2003
关键词
sodium pump; glucocorticoid receptor; glucocorticoid response element; promoter; alveolar fluid; ion transport; type II cells
资金
- NHLBI NIH HHS [P50-HL-50152] Funding Source: Medline
Na+-K+-ATPase plays an essential role in active alveolar epithelial fluid resorption. In fetal and adult alveolar epithelial cells, glucocorticoids (GC) increase Na+-K+-ATPase activity and mRNA levels. We sought to define the mechanism of Na+-K+-ATPase gene upregulation by GC. In a rat alveolar epithelial cell line (RLE), dexamethasone (Dex) increased beta(1)-subunit Na+-K+-ATPase mRNA expression two- to threefold within 3 h after exposure to the GC. The increased gene expression was due to increased transcription as demonstrated by nuclear run-on assays, whereas mRNA stability remained unchanged. Transient transfection of 5' deletion mutants of a beta(1) promoter-reporter construct demonstrated a 1.5- to 2.2-fold increase in promoter activity by Dex. All of the 5' deletion constructs contained partial or palindromic GC regulatory elements (GRE) and responded to GC. The increased expression of promoter reporter was inhibited by RU-486, a GC receptor (GR) antagonist, suggesting the involvement of GR. The palindromic GRE at -631 demonstrated Dex induction in a heterologous promoter construct. Gel mobility shift assays using RLE nuclear extracts demonstrated specific binding to this site and the presence of GR. We conclude that GC directly stimulate transcription of Na+-K+-ATPase beta(1) gene expression in adult rat lung epithelial cells through a GR-dependent mechanism that can act at multiple sites.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据