title: Role of PKC-α in NF-κB-MT1-MMP-mediated activation of proMMP-2 by TNF-α in pulmonary artery smooth muscle cells.
abstract: We sought to evaluate the mechanism(s) associated with pro matrix metalloprotease 2 (proMMP-2) activation in bovine pulmonary artery smooth muscle cells. Preincubation of cells with anti-TNFR1 antibody prevented tumour necrosis factor-α (TNF-α)-induced proMMP-2 activation and increase in membrane type 1 matrix metalloprotease (MT1-MMP) expression as well as inhibition of tissue inhibitor of metalloproteinase 2 (TIMP-2) expression, indicating the role of TNFR1 receptor during TNF-α stimulation. Anti-MT1-MMP antibody abrogated proMMP-2 activation by TNF-α-stimulated cell membrane, suggesting the involvement of MT1-MMP in proMMP-2 activation. Induction of MT1-MMP expression in response to TNF-α occurs via activation of nuclear factor (NF)-κB on inhibitory κB kinase (IKK) activation and subsequently phosphorylation/degradation of IκB-α. Inhibition of protein kinase C (PKC)-α activity by Go6976 and PKC-α siRNA prevented TNF-α-induced IKK activity, IκB-α phosphorylation/degradation and NF-κB activation. Inhibition of PKC-α activity also prevented TNF-α-induced MT1-MMP expression and proMMP-2 activation as well as down regulation of TIMP-2 expression. Inhibition of IκB-α phosphorylation by PS-1145, an IKK selective inhibitor, prevented TNF-α-induced increase in MT1-MMP expression and proMMP-2 activation, which although did not alter inhibition of TIMP-2 expression. Overall, we unravelled a hitherto unknown mechanism of the involvement of PKC-α in proMMP-2 activation and inhibition of TIMP-2 expression by NF-κB-MT1-MMP-dependent and -independent pathway, respectively, during TNF-α stimulation in pulmonary artery smooth muscle cells.
authors.affiliation: Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India.
authors.forename: Soumitra
authors.initials: S
authors.lastname: Roy
authors.forename: Tapati
authors.initials: T
authors.lastname: Chakraborti
authors.forename: Animesh
authors.initials: A
authors.lastname: Chowdhury
authors.forename: Sajal
authors.initials: S
authors.lastname: Chakraborti
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D015153:Blotting, Western; D002417:Cattle; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000378:metabolism*; D018093:Gelatinases / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D051550:I-kappa B Kinase / Q000378:metabolism; D020672:I-kappa B Proteins / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism*; D011651:Pulmonary Artery / Q000166:cytology; D034622:RNA Interference; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000911:Antibodies, Monoclonal; D004792:Enzyme Precursors; D020672:I-kappa B Proteins; D016328:NF-kappa B; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D019716:Tissue Inhibitor of Metalloproteinase-2; D000072000:NF-KappaB Inhibitor alpha; D051550:I-kappa B Kinase; D051571:Protein Kinase C-alpha; D018093:Gelatinases; C069860:progelatinase; D053511:Matrix Metalloproteinase 14