title: Tumor necrosis factor induces matrix metalloproteinases in cardiomyocytes and cardiofibroblasts differentially via superoxide production in a PI3Kgamma-dependent manner.
abstract: Tumor necrosis factor (TNF) is an inflammatory cytokine that is upregulated in a number of cardiomyopathies. Adverse cardiac remodeling and dilation result from degradation of the extracellular matrix by matrix metalloproteinases (MMPs). We investigated whether TNF can directly trigger expression and activation of MMPs in cardiac cells. We compared MMP expression profile and activities between primary cultures of mouse neonatal cardiomyocytes and cardiofibroblasts and in cellular and extracellular compartments. In response to recombinant TNF (rTNF, 20 ng/ml), cardiomyocytes exhibited faster and more pronounced superoxide production compared with cardiofibroblasts, concomitant with increased expression of several MMPs. MMP9 levels increased more rapidly and about twofold more in cardiomyocytes than in cardiofibroblasts. TNF did not induce MMP2 expression. Expression of collagenases (MMP8, MMP12, MMP13, and MMP14) increased significantly, while total collagenase activity increased to a greater degree in conditioned medium of cardiomyocytes than in cardiofibroblasts. rTNF-mediated MMP expression and activation were dependent on superoxide production and were blocked by apocynin, an NADPH oxidase inhibitor. We identified phosphatidylinositol 3-kinase (PI3K)gamma as a key factor in TNF-mediated events since TNF-induced superoxide production, MMP expression, and activity were significantly suppressed in cardiomyocytes and cardiofibroblasts deficient in PI3Kgamma. We further demonstrated that the TNF-superoxide-MMP axis of events is in fact activated in heart disease in vivo. Wild-type and TNF(-/-) mice subjected to cardiac pressure overload revealed that TNF deficiency resulted in reduced superoxide levels, collagenase activities, PI3K activity, and fibrosis leading to attenuated cardiac dilation and dysfunction. Our study demonstrates that TNF triggers expression and activation of MMPs faster and stronger in cardiomyocytes than in cardiofibroblasts in a superoxide-dependent manner and via activation of PI3Kgamma, thereby contributing to adverse myocardial remodeling in disease.
authors.affiliation: Dept. of Physiology, Univ. of Alberta, 474 HMRC, Edmonton, AB T6G 2S2, Canada.
authors.forename: Ahmed E
authors.initials: AE
authors.lastname: Awad
authors.forename: Vijay
authors.initials: V
authors.lastname: Kandalam
authors.forename: Subhadeep
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Wang
authors.forename: Josef M
authors.initials: JM
authors.lastname: Penninger
authors.forename: Sandra T
authors.initials: ST
authors.lastname: Davidge
authors.forename: Gavin Y
authors.initials: GY
authors.lastname: Oudit
authors.forename: Zamaneh
authors.initials: Z
authors.lastname: Kassiri
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D009202:Cardiomyopathies / Q000201:enzymology* / Q000503:physiopathology; D002478:Cells, Cultured; D058544:Class Ib Phosphatidylinositol 3-Kinase; D017077:Culture Media, Conditioned / Q000378:metabolism; D004195:Disease Models, Animal; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D020257:Ventricular Remodeling
chemical_list: D000098:Acetophenones; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; C056165:acetovanillone; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546760:PIK3CG protein, human; C546764:Pik3cg protein, mouse; D020782:Matrix Metalloproteinases