title: MMPs 2 and 9 are essential for coronary collateral growth and are prominently regulated by p38 MAPK.
abstract: Transient, repetitive ischemia (RI) stimulates coronary collateral growth (CCG) in normal, healthy (SD) rats, which requires p38 MAPK activation. In contrast, RI does not induce CCG in the metabolic syndrome (JCR) rats, which is associated with lack of p38 MAPK activation. The functional consequences of p38 MAPK activation in CCG remain unknown. Theoretically, effective collateral growth would require extracellular matrix remodeling; however, direct assessment as well as identification of proteases responsible for this degradation are lacking. In this study, we investigated the role of p38 MAPK in the regulation of matrix metalloproteinases 2 and 9 (MMPs 2 and 9) and their requirement for CCG in SD vs. JCR rats. The rats underwent the RI protocol (8 LAD occlusions, 40s each, every 20min, in 8h cycles for 0, 3, 6, or 9days). MMP expression was measured in the ischemic, collateral-dependent zone (CZ) and the normal zone (NZ) by Western blot, and MMP activity by zymography. Expression and activation of MMP 2 and 9 were significantly increased (~3.5 fold) on day 3 of RI in the CZ of SD rats. In vivo p38 MAPK inhibition completely blocked RI-induced MMP 2 and 9 expression and activation. MMP activation correlated with increased degradation of components of the basement membrane and the vascular elastic laminae: elastin (~3 fold), laminin (~3 fold) and type IV collagen (~2 fold). This was blocked by MMP 2 and 9 inhibition, which also abolished RI-induced CCG. In contrast, in JCR rats, RI did not induce expression or activation of MMP 2 or 9 and there was no associated degradation of elastin, laminin or type IV collagen. In conclusion, MMP 2 and 9 activation is essential for CCG and is mediated, in part, by p38 MAPK. Furthermore, compromised CCG in the metabolic syndrome may be partially due to the lack of p38 MAPK-dependent activation of MMP 2 and 9 and resultant decreased extracellular matrix degradation.
authors: Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA.
authors: Tracy
authors: T
authors: Dodd
authors: Rashmi
authors: R
authors: Jadhav
authors: Luke
authors: L
authors: Wiggins
authors: James
authors: J
authors: Stewart
authors: Erika
authors: E
authors: Smith
authors: James C
authors: JC
authors: Russell
authors: Petra
authors: P
authors: Rocic
mesh_terms: D000818:Animals; D024141:Collagen Type IV / Q000378:metabolism; D003097:Collateral Circulation; D003331:Coronary Vessels / Q000201:enzymology*; D004549:Elastin / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D007797:Laminin / Q000378:metabolism; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D017202:Myocardial Ischemia / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D024141:Collagen Type IV; D007093:Imidazoles; D007797:Laminin; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D004549:Elastin; D048051:p38 Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; C093642:SB 203580