Altered balance between matrix gelatinases (MMP‐2 and MMP‐9) and their tissue inhibitors in human dilated cardiomyopathy: potential role of MMP‐9 in myosin‐heavy chain degradation

Abstract

Background: End‐stage of human dilated cardiomyopathy (DCM) is characterized by myocyte loss and fibrosis, and associated with ventricular dilatation and reduced cardiac function. Matrix metalloproteinases (MMPs) and their natural tissue inhibitors (TIMPs) have been involved in the myocardial remodeling. Aims: To evaluate the potential role of matrix gelatinases (MMP‐2 and MMP‐9) in DCM, the balance between gelatinases and TIMPs and the gelatinase localization were investigated in left free wall ventricles from six normal donors and six patients with DCM at the transplantation time. Methods: TIMP‐(1, 2, 3 and 4) mRNAs were analyzed by quantitative reverse transcription‐polymerase chain reaction (RT‐PCR). TIMP‐1 and ‐2 protein content was assessed by ELISA. MMP‐2 and MMP‐9 expression were examined by zymography and immunological techniques. Results: All TIMPs were down‐regulated in DCM hearts, especially TIMP‐1 (reduced by 80%). Gel zymography revealed similar activity of MMP‐2 and MMP‐9 in both tissues. By in situ zymography and immunohistochemistry, active and immunoreactive gelatinases were pericardiomyocyte in control hearts and intracardiomyocyte in DCM hearts. Intracellular MMPs were associated with sarcomeric structure in DCM. To estimate a putative role of these gelatinases, several sarcomeric contractile proteins were digested in vitro by purified active MMP‐9. Only myosin‐heavy chain was cleaved in vitro giving 180‐, 120‐, 80‐ and 20‐kDa proteolytic fragments. In vivo, two major myosin‐heavy chain proteolytic fragments (80 and 20 kDa) were detected by specific monoclonal antibody against myosin‐heavy chain in DCM left ventricular homogenates, only. Conclusions: Taken together, these data highly suggest that MMP‐2 and MMP‐9 may be involved in the disorganization of the contractile apparatus in DCM hearts.

Right ventricular morphology and function is not related with microRNAs and fibrosis markers in dilated cardiomyopathy

“…There are no studies directly addressing the relationship between ECM fibrosis and serum markers of ECM metabolism with RV morphology and function in DCM. Past studies have shown that the percentage of myocardial collagen type I, III and IV significantly differs between LV and RV in DCM, and the same has been discovered for expressions of MMP-1, MMP-2, and MMP-9 [15]. These established findings support the hypothesis that distinct patterns of ECM structure, and particular turnover pathways, exist in the RV and LV [16].…”

Gelatinase-mediated migration and invasion of cancer cells

“…Interleukin receptor IL-2Rα no yes (Sheu et al, 2001) KiSS-1 protein/metastin yes yes (Takino et al, 2003) Kit-ligand yes (Heissig et al, 2002) Monocyte chemoattractant protein MCP-3 yes no (McQuibban et al, 2002) Monokine induced by interferon IFN-γ (MIG/CXCL -9) yes (Van den Myelin basic protein yes yes (Chandler et al, 1995) Myosin heavy chain yes yes (Rouet-Benzineb et al, 1999) Plasminogen yes yes (O'Reilly et al, 1999;Patterson and Sang, 1997) Platelet factor (PF)-4 yes…”

Type IV collagen degradation in the myocardial basement membrane after unloading of the failing heart by a left ventricular assist device

“…To demonstrate active MMP-2 in frozen heart tissue sections, ISZ was performed according to Rouet-Benzineb et al 29 Lysis of the substrate at the side of active MMP resulted in fluorescence, assessed by fluorescent microscopy or confocal laser scan microscopy. To test whether fluorescence was specific, some slides were preincubated with an MMP inhibitor (phenanthroline monohydrate (20 mg/ml; Sigma) in Tris-HCl) and incubated with the substrate in combination with the inhibitor.…”