The renin-angiotensin system mediates hyperoxia-induced collagen production in human lung fibroblasts.
A high concentration of oxygen can cause lung injury and lead to pulmonary fibrosis. Angiotensin (Ang) II induces human lung fibroblast proliferation and stimulates collagen synthesis. However, the role of the renin-angiotensin system (RAS) in the pathogenesis of hyperoxia-induced collagen production is unclear. The aims of this study were to investigate the effects of hyperoxia on the components of the RAS and collagen expression in human lung fibroblasts (MRC-5). Hyperoxia increased total collagen, collagen type I, and alpha-smooth muscle actin (alpha-SMA) mRNA and protein expression. RAS components and Ang II production were also significantly increased after hyperoxic exposure. Hyperoxia induced Ang II type 1 receptor (AT1R) expression but did not alter AT2R expression, furthermore, silencing of AT1R signaling with small interfering RNA suppressed hyperoxia-induced phosphorylated-ERK (p-ERK) 1/2, alpha-SMA, and collagen type I expression. Ang II increased p-ERK 1/2 and collagen type I expression, and these increases were inhibited by the AT1R inhibitor, losartan, but not by the AT2R inhibitor, PD123319 under both normoxic and hyperoxic conditions. These data suggest Ang II-mediated signaling transduction via AT1R is involved in hyperoxia-induced collagen synthesis in human lung fibroblasts.
Lang
Yaw-Dong
YD
Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan.
Hung
Chien-Lung
CL
Wu
Tzu-Ying
TY
Wang
Leng-Fang
LF
Chen
Chung-Ming
CM
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D057912:Angiotensin II Type 2 Receptor Blockers; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018496:Hyperoxia; D007093:Imidazoles / Q000494:pharmacology; D019808:Losartan / Q000494:pharmacology; D008168:Lung / Q000473:pathology; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000235:genetics; D015398:Signal Transduction
C541116:ACTA2 protein, human; D000199:Actins; D047228:Angiotensin II Type 1 Receptor Blockers; D057912:Angiotensin II Type 2 Receptor Blockers; D024042:Collagen Type I; D007093:Imidazoles; D011725:Pyridines; D034741:RNA, Small Interfering; D044140:Receptor, Angiotensin, Type 1; C073402:PD 123319; D019808:Losartan