Effects of angiotensin on the expression of  fibrosis-associated cytokines, growth factors,  and matrix proteins in human lung fibroblasts.
OBJECTIVE
Angiotensin (Ang) II plays an important role in fibrogenesis in various organs, including the lung. The aim of this study is to elucidate (i) the effects of Ang II on the expression of cytokines, growth factors or matrix proteins in normal human lung fibroblasts, and (ii) the inhibitory effects of an Ang II type 1 (AT1) receptor blocker, candesartan.


METHODS
Normal human adult lung fibroblasts were cultured. Candesartan was added and the cells were incubated. All the cells in culture dishes were collected at day 0 and 2, and the cell numbers were counted using a Neubauer haemocytometer (Clay-Adams, Parsippany, NJ, USA). The cell proliferation rates at day 2 were calculated in comparison to those at day 0. Total cellular RNA was extracted for real-time quantitative PCR, or the culture supernatant was collected for either a Sircol assay or enzyme-linked immunosorbent assay (ELISA). Laser scanning confocal microscopy was used for analyzing the cells with and without prior exposure to candesartan. Comparisons between the means of multiple groups were analyzed by one-way analysis of variance (ANOVA) followed by Tukey's test or Games-Howell's test. Values of P < 0*05 were considered to be statistically significant.


RESULTS
Among the 12 fibrosis-associated cytokines and growth factors, mRNA expressions of interleukin (IL)-4, IL-7, and platelet-derived growth factor-D were significantly modulated by Ang II, and suppressed by candesartan. Soluble collagen and elastin levels were significantly elevated by Ang II, and suppressed by candesartan. Under confocal microscopy, the intracellular distribution of elastin was significantly increased by Ang II, and suppressed by candesartan.


CONCLUSIONS
These data indicate that Ang II promotes lung fibrosis by increasing the matrix formation, which was suppressed by AT1 receptor blocker.
Okada
Makoto
M
Division of Rheumatology, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Saitama, Japan. grd1804@ndmc
Suzuki
K
K
Matsumoto
M
M
Takada
K
K
Nakanishi
T
T
Horikoshi
H
H
Higuchi
T
T
Hosono
Y
Y
Nakayama
M
M
Ohsuzu
F
F
D000328:Adult; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D001713:Biphenyl Compounds; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000187:drug effects / Q000378:metabolism; D004549:Elastin / Q000187:drug effects / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D013777:Tetrazoles / Q000494:pharmacology*
D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D016207:Cytokines; D016326:Extracellular Matrix Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D013777:Tetrazoles; D000804:Angiotensin II; D003094:Collagen; D004549:Elastin; C081643:candesartan