Activation of proMMP-2 and Src by HHV8 vGPCR in human pulmonary arterial endothelial cells

J Mol Cell Cardiol. 2007 Mar;42(3):517-25. doi: 10.1016/j.yjmcc.2006.08.004. Epub 2006 Dec 26.

Abstract

Idiopathic pulmonary arterial hypertension (iPAH) is associated with human herpesvirus 8 (HHV8) infection and demonstrates pathological angiogenesis similar to that observed with another HHV8-linked disease, namely Kaposi Sarcoma (KS). Importantly, the HHV8 encoded viral G-protein-coupled receptor (vGPCR) induces KS lesions in a murine model. Investigating the impact of vGPCR expression on the angiogenic activity of human pulmonary arterial endothelial cells (HPAEC) can yield insight into the pathobiology of HHV8-associated vascular disorders, particularly PAH. Cultured HPAECs were transduced with retroviral vectors carrying either control or vGPCR coding regions. vGPCR expression selectively activated matrix metalloproteinase (MMP)-2, a pivotal matrix modulating enzyme during angiogenesis. A membrane type 1 MMP (MT1-MMP) neutralizing antibody and the tissue inhibitor of metalloproteinases-2 (TIMP-2) independently blocked vGPCR-induced MMP-2 activation. vGPCR expression concordantly promoted MMP-2 activation by increasing MT1-MMP expression while decreasing TIMP-2 expression. vGPCR activated Src kinase as demonstrated by phosphorylation of Src and its substrate focal adhesion kinase (FAK). vGPCR promoted angiogenesis of HPAECs as demonstrated by a substantial increase in tubulogenesis in vitro. The Src inhibitors PP2 and SU6656 significantly diminished vGPCR-induced MMP-2 activation and tubulogenesis. Our findings indicate that vGPCR induces MMP-2 activation in HPAECs through regulation of MT1-MMP and TIMP-2 expression. vGPCR activates Src and inhibition of such activation abrogates proMMP-2 activation and in vitro angiogenesis induced by vGCPR. The current study implicates vGPCR as an etiological agent in iPAH and identifies Src and MMP-2 as potential therapeutic targets in HHV8 associated KS and iPAH.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Membrane / enzymology
  • Cells, Cultured
  • Endothelial Cells / metabolism*
  • Enzyme Activation
  • Gene Expression Regulation, Enzymologic
  • Herpesvirus 8, Human / genetics
  • Herpesvirus 8, Human / metabolism*
  • Humans
  • Matrix Metalloproteinase 8 / genetics
  • Matrix Metalloproteinase 8 / metabolism*
  • Neovascularization, Physiologic
  • Pulmonary Artery / metabolism*
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*
  • src-Family Kinases / metabolism

Substances

  • Receptors, G-Protein-Coupled
  • Viral Proteins
  • src-Family Kinases
  • MMP8 protein, human
  • Matrix Metalloproteinase 8