TY - JOUR
T1 - Lysocardiolipin acyltransferase regulates TGF-β mediated lung fibroblast differentiation
AU - Huang, Long Shuang
AU - Jiang, Peiyue
AU - Feghali-Bostwick, Carol
AU - Reddy, Sekhar P.
AU - Garcia, Joe G.N.
AU - Natarajan, Viswanathan
N1 - Publisher Copyright:
© 2017 Elsevier Inc.
PY - 2017/11
Y1 - 2017/11
N2 - Lysocardiolipin acyltransferase (LYCAT), a cardiolipin remodeling enzyme, plays a key role in mitochondrial function and vascular development. We previously reported that reduced LYCAT mRNA levels in peripheral blood mononuclear cells correlated with poor pulmonary function outcomes and decreased survival in IPF patients. Further LYCAT overexpression reduced lung fibrosis, and LYCAT knockdown accentuated experimental pulmonary fibrosis. NADPH Oxidase 4 (NOX4) expression and oxidative stress are known to contribute to lung fibroblast differentiation and progression of fibrosis. In this study, we investigated the role of LYCAT in TGF-β mediated differentiation of human lung fibroblasts to myofibroblasts, and whether this occurred through mitochondrial superoxide and NOX4 mediated hydrogen peroxide (H2O2) generation. Our data indicated that LYCAT expression was up-regulated in primary lung fibroblasts isolated from IPF patients and bleomycin-challenged mice, compared to controls. In vitro, siRNA-mediated SMAD3 depletion inhibited TGF-β stimulated LYCAT expression in human lung fibroblasts. ChIP immunoprecipitation assay revealed TGF-β stimulated SMAD2/3 binding to the endogenous LYCAT promoter, and mutation of the SMAD2/3 binding sites (−179/−183 and −540/−544) reduced TGF-β-stimulated LYCAT promoter activity. Overexpression of LYCAT attenuated TGF-β-induced mitochondrial and intracellular oxidative stress, NOX4 expression and differentiation of human lung fibroblasts. Further, pretreatment with Mito-TEMPO, a mitochondrial superoxide scavenger, blocked TGF-β-induced mitochondrial superoxide, NOX4 expression and differentiation of human lung fibroblasts. Treatment of human lung fibroblast with NOX1/NOX4 inhibitor, GKT137831, also attenuated TGF-β induced fibroblast differentiation and mitochondrial oxidative stress. Collectively, these results suggest that LYCAT is a negative regulator of TGF-β-induced lung fibroblast differentiation by modulation of mitochondrial superoxide and NOX4 dependent H2O2 generation, and this may serve as a potential therapeutic target for human lung fibrosis.
AB - Lysocardiolipin acyltransferase (LYCAT), a cardiolipin remodeling enzyme, plays a key role in mitochondrial function and vascular development. We previously reported that reduced LYCAT mRNA levels in peripheral blood mononuclear cells correlated with poor pulmonary function outcomes and decreased survival in IPF patients. Further LYCAT overexpression reduced lung fibrosis, and LYCAT knockdown accentuated experimental pulmonary fibrosis. NADPH Oxidase 4 (NOX4) expression and oxidative stress are known to contribute to lung fibroblast differentiation and progression of fibrosis. In this study, we investigated the role of LYCAT in TGF-β mediated differentiation of human lung fibroblasts to myofibroblasts, and whether this occurred through mitochondrial superoxide and NOX4 mediated hydrogen peroxide (H2O2) generation. Our data indicated that LYCAT expression was up-regulated in primary lung fibroblasts isolated from IPF patients and bleomycin-challenged mice, compared to controls. In vitro, siRNA-mediated SMAD3 depletion inhibited TGF-β stimulated LYCAT expression in human lung fibroblasts. ChIP immunoprecipitation assay revealed TGF-β stimulated SMAD2/3 binding to the endogenous LYCAT promoter, and mutation of the SMAD2/3 binding sites (−179/−183 and −540/−544) reduced TGF-β-stimulated LYCAT promoter activity. Overexpression of LYCAT attenuated TGF-β-induced mitochondrial and intracellular oxidative stress, NOX4 expression and differentiation of human lung fibroblasts. Further, pretreatment with Mito-TEMPO, a mitochondrial superoxide scavenger, blocked TGF-β-induced mitochondrial superoxide, NOX4 expression and differentiation of human lung fibroblasts. Treatment of human lung fibroblast with NOX1/NOX4 inhibitor, GKT137831, also attenuated TGF-β induced fibroblast differentiation and mitochondrial oxidative stress. Collectively, these results suggest that LYCAT is a negative regulator of TGF-β-induced lung fibroblast differentiation by modulation of mitochondrial superoxide and NOX4 dependent H2O2 generation, and this may serve as a potential therapeutic target for human lung fibrosis.
KW - Fibroblast differentiation
KW - LYCAT
KW - Mitochondrial oxidative stress
KW - Pulmonary fibrosis
KW - TGF-β
UR - http://www.scopus.com/inward/record.url?scp=85026778982&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85026778982&partnerID=8YFLogxK
U2 - 10.1016/j.freeradbiomed.2017.07.023
DO - 10.1016/j.freeradbiomed.2017.07.023
M3 - Article
C2 - 28751023
AN - SCOPUS:85026778982
SN - 0891-5849
VL - 112
SP - 162
EP - 173
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
ER -