The Nox4 inhibitor GKT137831 attenuates hypoxia-induced pulmonary vascular cell proliferation

Am J Respir Cell Mol Biol. 2012 Nov;47(5):718-26. doi: 10.1165/rcmb.2011-0418OC. Epub 2012 Aug 16.


Increased NADP reduced (NADPH) oxidase 4 (Nox4) and reduced expression of the nuclear hormone receptor peroxisome proliferator-activated receptor γ (PPARγ) contribute to hypoxia-induced pulmonary hypertension (PH). To examine the role of Nox4 activity in pulmonary vascular cell proliferation and PH, the current study used a novel Nox4 inhibitor, GKT137831, in hypoxia-exposed human pulmonary artery endothelial or smooth muscle cells (HPAECs or HPASMCs) in vitro and in hypoxia-treated mice in vivo. HPAECs or HPASMCs were exposed to normoxia or hypoxia (1% O(2)) for 72 hours with or without GKT137831. Cell proliferation and Nox4, PPARγ, and transforming growth factor (TGF)β1 expression were measured. C57Bl/6 mice were exposed to normoxia or hypoxia (10% O(2)) for 3 weeks with or without GKT137831 treatment during the final 10 days of exposure. Lung PPARγ and TGF-β1 expression, right ventricular hypertrophy (RVH), right ventricular systolic pressure (RVSP), and pulmonary vascular remodeling were measured. GKT137831 attenuated hypoxia-induced H(2)O(2) release, proliferation, and TGF-β1 expression and blunted reductions in PPARγ in HPAECs and HPASMCs in vitro. In vivo GKT137831 inhibited hypoxia-induced increases in TGF-β1 and reductions in PPARγ expression and attenuated RVH and pulmonary artery wall thickness but not increases in RVSP or muscularization of small arterioles. This study shows that Nox4 plays a critical role in modulating proliferative responses of pulmonary vascular wall cells. Targeting Nox4 with GKT137831 provides a novel strategy to attenuate hypoxia-induced alterations in pulmonary vascular wall cells that contribute to vascular remodeling and RVH, key features involved in PH pathogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Hypoxia
  • Cell Proliferation / drug effects*
  • Cells, Cultured
  • Endothelial Cells / drug effects*
  • Endothelial Cells / enzymology
  • Endothelial Cells / physiology
  • Endothelium, Vascular / pathology
  • Gene Expression / drug effects
  • Gene Knockdown Techniques
  • Humans
  • Hydrogen Peroxide / metabolism
  • Hypertension, Pulmonary / drug therapy
  • Hypertension, Pulmonary / enzymology
  • Hypertension, Pulmonary / pathology
  • Lung / drug effects
  • Lung / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Myocytes, Smooth Muscle / drug effects*
  • Myocytes, Smooth Muscle / enzymology
  • Myocytes, Smooth Muscle / physiology
  • NADPH Oxidase 4
  • NADPH Oxidases / antagonists & inhibitors*
  • NADPH Oxidases / genetics
  • NADPH Oxidases / metabolism
  • PPAR gamma / genetics
  • PPAR gamma / metabolism
  • Proliferating Cell Nuclear Antigen / metabolism
  • Pulmonary Artery / pathology*
  • Pyrazoles / pharmacology*
  • Pyrazoles / therapeutic use
  • Pyridines / pharmacology*
  • Pyridines / therapeutic use
  • RNA Interference
  • Rosiglitazone
  • Thiazolidinediones / pharmacology
  • Thiazolidinediones / therapeutic use
  • Transforming Growth Factor beta1 / genetics
  • Transforming Growth Factor beta1 / metabolism
  • Ventricular Remodeling / drug effects


  • PPAR gamma
  • Proliferating Cell Nuclear Antigen
  • Pyrazoles
  • Pyridines
  • Thiazolidinediones
  • Transforming Growth Factor beta1
  • Rosiglitazone
  • setanaxib
  • Hydrogen Peroxide
  • NADPH Oxidase 4
  • NADPH Oxidases
  • NOX4 protein, human