Document Detail


Pyruvate dehydrogenase inhibition by the inflammatory cytokine TNFα contributes to the pathogenesis of pulmonary arterial hypertension.
MedLine Citation:
PMID:  21809123     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Pulmonary arterial hypertension (PAH) is a vascular remodeling disease characterized by enhanced proliferation and suppressed apoptosis of pulmonary artery smooth muscle cells (PASMC). This apoptosis resistance is characterized by PASMC mitochondrial hyperpolarization [in part, due to decreased pyruvate dehydrogenase (PDH) activity], decreased mitochondrial reactive oxygen species (mROS), downregulation of Kv1.5, increased [Ca(++)](i), and activation of the transcription factor nuclear factor of activated T cells (NFAT). Inflammatory cells are present within and around the remodeled arteries and patients with PAH have elevated levels of inflammatory cytokines, including tumor necrosis factor-α (TNFα). We hypothesized that the inflammatory cytokine TNFα inhibits PASMC PDH activity, inducing a PAH phenotype in normal PASMC. We exposed normal human PASMC to recombinant human TNFα and measured PDH activity. In TNFα-treated cells, PDH activity was significantly decreased. Similar to exogenous TNFα, endogenous TNFα secreted from activated human CD8(+) T cells, but not quiescent T cells, caused mitochondrial hyperpolarization, decreased mROS, decreased K(+) current, increased [Ca(++)](i), and activated NFAT in normal human PASMC. A TNFα antibody completely prevented, while recombinant TNFα mimicked the T cell-induced effects. In vivo, the TNFα antagonist etanercept prevented and reversed monocrotaline (MCT)-induced PAH. In a separate model, T cell deficient rats developed less severe MCT-induced PAH compared to their controls. We show that TNFα can inhibit PASMC PDH activity and induce a PAH phenotype. Our work supports the use of anti-inflammatory therapies for PAH.
Authors:
Gopinath Sutendra; Peter Dromparis; Sébastien Bonnet; Alois Haromy; Michael S McMurtry; R Chris Bleackley; Evangelos D Michelakis
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-8-2
Journal Detail:
Title:  Journal of molecular medicine (Berlin, Germany)     Volume:  -     ISSN:  1432-1440     ISO Abbreviation:  -     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-8-2     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9504370     Medline TA:  J Mol Med (Berl)     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Medicine (Pulmonary Hypertension Program), University of Alberta, Edmonton, Canada.
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