TGF-β1stimulates HDAC4 nucleus-to-cytoplasm translocation and NADPH oxidase 4-derived reactive oxygen species in normal human lung fibroblasts.
Myofibroblasts are important mediators of fibrogenesis; thus blocking fibroblast-to-myofibroblast differentiation (FMD) may be an effective strategy to treat pulmonary fibrosis (PF). Previously, we reported that histone deacetylase 4 (HDAC4) activity is necessary for transforming growth factor-β1(TGF-β1)-induced human lung FMD. Here, we show that TGF-β1increases NADPH oxidase 4 (NOX4) mRNA and protein expression in normal human lung fibroblasts (NHLFs) and causes nuclear export of HDAC4. Application of the NOX family inhibitor diphenyleneiodonium chloride reduces TGF-β1-induced HDAC4 nuclear export, expression of the myofibroblast marker α-smooth muscle actin (α-SMA), and α-SMA fiber formation. Inhibition of HDAC4 nucleus-to-cytoplasm translocation using leptomycin B (LMB) had little effect on α-SMA expression but blocked α-SMA fiber formation. A coimmunoprecipitation assay showed that HDAC4 associates with α-SMA. Moreover, LMB abolishes TGF-β1-induced α-SMA fiber formation and cell contraction. Relevant to human pulmonary fibrosis, idiopathic PF specimens showed significantly higher NOX4 RNA expression and scant HDAC4 staining within nuclei of fibroblast foci myofibroblasts. Taken together, these results indicate that reactive oxygen species promote TGF-β1-mediated myofibroblast differentiation and HDAC4 nuclear export. The physical association of HDAC4 with α-SMA suggests that HDAC4 has a role in regulating the α-SMA cytoskeleton arrangement.
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana.
Weichao
W
Guo
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana.
Shigeki
S
Saito
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana.
Cecilia G
CG
Sanchez
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana.
Yan
Y
Zhuang
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana.
Rafael E
RE
Gongora Rosero
College of Medical Sciences, Washington State University-Spokane, Spokane, Washington; and.
Bin
B
Shan
Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas.
Fayong
F
Luo
Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Science Center, New Orleans, Louisiana; jlasky@tulane.edu.
Joseph A
JA
Lasky
D000199:Actins; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D001706:Biopsy; D002454:Cell Differentiation / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000201:enzymology / Q000473:pathology; D008168:Lung / Q000166:cytology*; D058628:Myofibroblasts / Q000473:pathology; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
C541116:ACTA2 protein, human; D000199:Actins; D017382:Reactive Oxygen Species; D012097:Repressor Proteins; D053773:Transforming Growth Factor beta1; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; C400300:HDAC4 protein, human; D006655:Histone Deacetylases
HDAC4; IPF; NOX4; myofibroblasts; reactive oxygen species; α-smooth muscle actin