Activation of proMMP-2 and Src by HHV8 vGPCR in human pulmonary arterial endothelial cells.
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.
Shan
Bin
B
Department of Medicine, Pulmonary Section, Department of Microbiology, Tulane Cancer Center and Program in Lung Biology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
Morris
Cindy A
CA
Zhuo
Ying
Y
Shelby
Bryan D
BD
Levy
Dawn R
DR
Lasky
Joseph A
JA
D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020784:Matrix Metalloproteinase 8 / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D011651:Pulmonary Artery / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
D043562:Receptors, G-Protein-Coupled; D014764:Viral Proteins; D019061:src-Family Kinases; C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8