Reduced MMP-2 activity contributes to cardiac fibrosis in experimental diabetic cardiomyopathy (original) (raw)
Related papers
Diabetes, 2007
We investigated the effect of the angiotensin type 1 (AT-1) receptor antagonist, irbesartan, on matrix metalloproteinase (MMP) activity and cardiac cytokines in an animal model of diabetic cardiomyopathy. Diabetes was induced in 20 C57/bl6 mice by injection of streptozotocin (STZ). These animals were treated with irbesartan or placebo and were compared with nondiabetic controls. Left ventricular (LV) function was measured by pressure-volume loops with parameters for systolic function (end systolic elastance [Ees]) and diastolic function (cardiac stiffness) 8 weeks after STZ treatment. The cardiac protein content of interleukin (IL)1 and transforming growth factor (TGF)1 were measured by enzyme-linked immunosorbent assay. The total cardiac collagen content and collagen type 1 and 3 were measured by histochemestry, and MMP-2 activity was measured by gelatin zymography. LV dysfunction was documented by impaired Ees and diastolic stiffness in STZ mice compared with controls. This was accompanied by increased TGF, IL1, and fibrosis and decreased MMP-2 activity. Treatment with irbesartan attenuated LV dysfunction, IL1, TGF, and cardiac fibrosis compared with untreated diabetic animals and normalized MMP activity. These findings present evidence that AT-1 receptor antagonists attenuate cardiac failure by decreasing cardiac inflammation and normalizing MMP activity, leading to normalized cardiac fibrosis in STZ-induced diabetic cardiomyopathy. Diabetes 56:641-646, 2007 RESEARCH DESIGN AND METHODS Diabetes was induced in 20 C57i/BL6J mice by injection of STZ (50 mg/kg i.p. for 5 days) dissolved in 0.1 mol/l sodium citrate, pH 4.5, as previously described (11). This dose is known to induce no acute renal failure in C57i/BL6J mice (12). Hyperglycemia (glucose Ͼ22 mmol/l) was confirmed 7 days later using a reflectance meter (Acutrend; Boehringer, Mannheim,
Migration of cardiac fibroblasts is implicated in in- farct healing and ventricular remodeling. Activation of matrix metalloproteinases induced by three-dimen- sional type I collagen, the principal component of the myocardial interstitium, is hypothesized to be essential for this migration. By utilizing primary cultures of car- diac fibroblasts and collagen lattice models, we demon- strated that type I collagen induced MMP-2 activation, and cells undergoing a change from isometric tension to mechanical unloading were associated with increased levels of total and active MMP-2 species. The collagen- induced MMP-2 activation coincided with up-regulated cellular levels of both membrane type 1-matrix metallo- proteinase (MT1-MMP) and TIMP-2. A fraction of cellu- lar membrane prepared from cells embedded in the col- lagen lattice containing active MT1-MMP and TIMP-2 was capable of activating pro-MMP-2, and exogenous TIMP-2 had a biphasic effect on this membrane-medi- ated MMP-2 activation. Interestingly, the presence of 43-kDa MT1-MMP species in a fraction of intracellular soluble proteins prepared from monolayer cells but not cells embedded in the lattices indicates that MT1-MMP metabolizes differently under the two different culture conditions. Treatment of cells embedded in the lattice with furin inhibitor attenuated pro-MT1-MMP process- ing and MMP-2 activation and impeded cell migration and invasion. These results suggest that the migration and invasion of cardiac fibroblasts is furin-dependent and that the active species of MT1-MMP and MMP-2 may be involved in both events.
Cardiovascular Pathology, 2014
Objective: Tissue inhibitor of metalloproteinase-2 (TIMP-2) is an endogenous inhibitor of matrix metalloproteinases (MMPs) that attenuates maladaptive cardiac remodeling in ischemic heart failure. We examined the effects of TIMP-2 on human cardiac fibroblast activation and extracellular matrix (ECM) remodeling. Methods: Human cardiac fibroblasts within a three-dimensional collagen matrix were assessed for phenotype conversion, ECM architecture and key molecular regulators of ECM remodeling after differential exposure to TIMP-2 and Ala+TIMP-2 (a modified TIMP-2 analogue devoid of MMP inhibitory activity). Results: TIMP-2 induced opposite effects on human cardiac fibroblast activation and ECM remodeling depending on concentration. TIMP-2 activated fibroblasts into contractile myofibroblasts that remodeled ECM. At higher concentrations (N10 nM), TIMP-2 inhibited fibroblast activation and prevented ECM remodeling. As compared to profibrotic cytokine transforming growth factor (TGF)-beta1, TIMP-2 activated fibroblasts and remodeled ECM without a net accumulation of matrix elements. TIMP-2 increased total protease activity as compared to TGF-beta1. Ala+TIMP-2 exposure revealed that the actions of TIMP-2 on cardiac fibroblast activation are independent of its effects on MMP inhibition. In the presence of GM6001, a broad-spectrum MMP inhibitor, TIMP-2-mediated ECM contraction was completely abolished, indicating that TIMP-2-mediated fibroblast activation is MMP dependent. Conclusion: TIMP-2 functions in a contextual fashion such that the effect on cardiac fibroblasts depends on the tissue microenvironment. These observations highlight potential clinical challenges in using TIMP-2 as a therapeutic strategy to attenuate postinjury cardiac remodeling.
Journal of Biological Chemistry, 2010
The membrane type-1 matrix metalloproteinase (MT1-MMP) is a unique member of the MMP family, but induction patterns and consequences of MT1-MMP overexpression (MT1-MMPexp), in a left ventricular (LV) remodeling process such as myocardial infarction (MI), have not been explored. MT1-MMP promoter activity (murine luciferase reporter) increased 20-fold at 3 days and 50-fold at 14 days post-MI. MI was then induced in mice with cardiac restricted MT1-MMPexp (n ؍ 58) and wild type (WT, n ؍ 60). Post-MI survival was reduced (67% versus 46%, p < 0.05), and LV ejection fraction was lower in the post-MI MT1-MMPexp mice compared with WT (41 ؎ 2 versus 32 ؎ 2%,p < 0.05). In the post-MI MT1-MMPexp mice, LV myocardial MMP activity, as assessed by radiotracer uptake, and MT1-MMP-specific proteolytic activity using a specific fluorogenic assay were both increased by 2-fold. LV collagen content was increased by nearly 2-fold in the post-MI MT1-MMPexp compared with WT. Using a validated fluorogenic construct, it was discovered that MT1-MMP proteolytically processed the pro-fibrotic molecule, . 2 The abbreviations used are: MMP, matrix metalloproteinase; LV, left ventricular; MI, myocardial infarction; LTBP-1, latency-associated transforming growth factor-1 binding protein; %ID, percentage of injected dose; MOPS, 4-morpholinepropanesulfonic acid; ANOVA, analysis of variance; rtPCR, real-time PCR. Downloaded from FIGURE 3. Representative LV sections in which MT1-MMP was localized by immunofluorescence using confocal microscopy in WT and MT1-MMPexp mice. Green fluorescence represents MT1-MMP, red fluorescence is indicative of rhodamine-phalloidin, and the blue stain is indicative of nuclei. Increased relative abundance and staining intensity for MT1-MMP was observed along the myocyte-matrix interface in LV sections taken MT1-MMPexp mice. At 14 days post-MI, a robust increase in MT1-MMP staining was observed within the MI region for both WT and MT1-MMPexp mice. However, in the MT1-MMPexp mice, a more robust and greater staining pattern was clearly observed within the remote regions. (Scale ϭ 20 m.)
American Journal of Physiology-Heart and Circulatory Physiology, 2006
Although enhanced cardiac matrix metalloproteinase (MMP)-2 synthesis has been associated with ventricular remodeling and failure, whether MMP-2 expression is a direct mediator of this process is unknown. We generated transgenic mice expressing active MMP-2 driven by the α-myosin heavy chain promoter. At 4 mo MMP-2 transgenic hearts demonstrated expression of the MMP-2 transgene, myocyte hypertrophy, breakdown of Z-band registration, lysis of myofilaments, disruption of sarcomere and mitochondrial architecture, and cardiac fibroblast proliferation. Hearts from 8-mo-old transgenic mice displayed extensive myocyte disorganization and dropout with replacement fibrosis and perivascular fibrosis. Older transgenic mice also exhibited a massive increase in cardiac MMP-2 expression, representing recruitment of endogenous MMP-2 synthesis, with associated expression of MMP-9 and membrane type 1 MMP. Increases in diastolic [control (C) 33 ± 3 vs. MMP 51 ± 12 μl; P = 0.003] and systolic (C 7 ± 2...
The role of matrix metalloproteinases in heart disease
Cardiovascular Research, 1996
lar matrix also contains hetero-polysaccharides (glycosaminoglycans), glycoproteins (heparan sulphate and chondroitin sulphate proteoglycans), microfibrillar proteins (fibrillin and fibulin) and elastin.
Journal of Cellular Biochemistry, 2005
Activations of MMP-2 and membrane type 1-matrix metalloproteinase (MT1-MMP) have been correlated with cell migration, a key cellular event in the wound healing and tissue remodeling. We have previously demonstrated furin-dependent MMP-2 and MT1-MMP activations induced by type I collagen in cardiac fibroblasts. To understand mechanistic aspects of the regulation of MMP-2 and MT1-MMP activations by potential non-matrix factor(s) in cardiac fibroblasts, in the present study, we examined the effects of various agents including concanavalin A (ConA), a proteolytic phenotype-producing agent. We showed that treatment of cells with ConA activated pro-MMP-2, and that this activation concurred with elevated levels of cellular MT1-MMP and TIMP-2. The presence of active MT1-MMP and 43 and 36 kDa processed forms of MT1-MMP in a fraction of intracellular proteins prepared from ConAtreated cells suggests the possible internalization of differential forms of MT1-MMP. The appearance of 36 kDa processed form of MT1-MMP in conditioned media prepared from ConA-treated cells indicates the possible extracellular release of the further processed MT1-MMP fragment. Inhibition of furin in ConA-treated cells attenuated pro-MT1-MMP processing and the cellular TIMP-2 level, plus it reduced cell-released active MMP-2 in a time-dependent manner. These results suggest the involvement of furin in the ConA-induced activations of MT1-MMP and MMP-2. Furthermore, the existence of furin inhibitor-insensitive pro-and active MMP-2 species associated with ConA-treated cells implies that a mechanism independent of furin may perhaps account for the binding of the MMP-2 species to the cells. Supplementary material for this article can be found atclonal antibody; MMP, matrix metalloproteinase; MT1-MMP, membrane type 1-matrix metalloproteinase; PBS-T, phosphate-buffered saline solution containing 0.1% (v/v) Tween-20; PMA, phorbol 12-myristate 13-acetate; Pro-MMP, matrix metalloproteinases with propeptide domain; PVDF, polyvinylidene difluoride; TIMP, tissue inhibitor of matrix metalloproteinases.
Matrix metalloproteinases and tissue remodeling in hypertrophic cardiomyopathy
American Heart Journal, 2008
Background Hypertrophic cardiomyopathy (HCM) is defined by the presence of unexplained left ventricular hypertrophy, myocyte disarray, and interstitial fibrosis. An increase in extracellular matrix produces interstitial fibrosis, by raised amounts of collagen type I/III. Regions of myocardial late gadolinium enhancement by cardiac magnetic resonance (CMR) represented increased myocardial collagen. Regarding the role of matrix metalloproteinases (MMPs) in myocardial remodeling and subsequent fibrosis, the aim of our study was to explore the relation between MMP system and myocardial late gadolinium enhancement by CMR (as expression of image-documented fibrosis) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (as a marker of cardiac overload) in HCM.