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PubMed2006

Understanding effects of matrix protease and matrix organization on directional persistence and translational speed in three-dimensional cell migration.

Recent studies have shown significant differences in migration mechanisms between two- and three-dimensional environments. While experiments have suggested a strong dependence of in vivo migration on both structure and proteolytic activity, the underlying biophysics of such dependence has not been studied adequately. In addition, the existing models of persistent random walk migration are primarily based on two-dimensional movement and do not account for the effect of proteolysis or matrix inhomogeneity. Using lattice Monte Carlo methods, we present a model to study the role of matrix metallo-proteases (MMPs) on directional persistence and speed. The simulations account for a given cell's ability to deform as well as to digest the matrix as the cell moves in three dimensions. Our results show a bimodal dependence of speed and persistence on matrix pore size and suggest high sensitivity on MMP activity, which is in very good agreement with experimental studies carried out in 3D matrices.

Cell Movement↗

PubMed2000

Interplay of matrix metalloproteinases, tissue inhibitors of metalloproteinases and their regulators in cardiac matrix remodeling.

Myocardial fibrosis due to maladaptive extracellular matrix remodeling contributes to dysfunction of the failing heart. Further elucidation of the mechanism by which myocardial fibrosis and dilatation can be prevented or even reversed remains of great interest as a potential means to limit myocardial remodeling and dysfunction. Matrix metalloproteinases (MMPs) are the driving force behind extracellular matrix degradation during remodeling and are increased in the failing human heart. MMPs are regulated by a variety of growth factors, cytokines, and matrix fragments such as matrikines. In the present report, we discuss the regulation of MMPs, the role of MMPs in the development of cardiac fibrosis, and the modulation of MMP activity using gene transfer and knockout technologies. We also present recent findings from our laboratory on the regulation of the extracellular MMP inducer (EMMPRIN), MMPs, and transforming growth factor-beta(1) in the failing human heart before and after left ventricular assist device support, as well as the possibility of preventing ventricular fibrosis using different anti-MMP strategies. Several studies suggest that such modulation of MMP activity can alter ventricular remodeling, myocardial dysfunction, and the progression of heart failure. It is therefore suggested that the interplay of MMPs and their regulators is important in the development of the heart failure phenotype, and myocardial fibrosis in heart failure may be modified by modulating MMP activity.

Animals↗

PubMed1997

Gene expression of matrix metalloproteinase-1 (interstitial collagenase) and matrix metalloproteinase-3 (stromelysin-1) in basal cell carcinoma by in situ hybridization using chondroitin ABC lyase.

The gene expression of matrix metalloproteinase-1 and -3 was examined in basal cell carcinomas by in situ hybridization using digoxigenin-labelled riboprobes. Nodulo-ulcerative basal cell carcinomas demonstrated the gene expression for both metalloproteinases but superficial basal cell carcinomas did not present any transcripts for them. Transcripts for matrix metalloproteinase-1 (interstitial collagenase) were demonstrated densely in stromal cells among tumour masses, and those for matrix metalloproteinase-3 (stromelysin-1) were detected only in more advanced cases. Neither were expressed in tumour cells. The two metalloproteinases were produced by stromal cells according to the tumour invasion process, in which various growth factors, cytokines and inflammatory factors, which could regulate gene expressions of matrix metalloproteinases, were involved. It was also found that hybridization signals were enhanced by treatment with chondroitin ABC lyase, which digested abundant glycosaminoglycans in basal cell carcinoma. The procedure for the digestion is simple, and appears to be of value for in situ hybridization studies on tissues containing large amounts of glycosaminoglycans.

Basal Cell Carcinoma↗

PubMed2000

Long-term prevention of renal insufficiency, excess matrix gene expression, and glomerular mesangial matrix expansion by treatment with monoclonal antitransforming growth factor-beta antibody in db/db diabetic mice.

Emerging evidence suggests that transforming growth factor-beta (TGF-beta) is an important mediator of diabetic nephropathy. We showed previously that short-term treatment with a neutralizing monoclonal anti-TGF-beta antibody (alphaT) in streptozotocin-diabetic mice prevents early changes of renal hypertrophy and increased matrix mRNA. To establish that overactivity of the renal TGF-beta system mediates the functional and structural changes of the more advanced stages of nephropathy, we tested whether chronic administration of alphaT prevents renal insufficiency and glomerulosclerosis in the db/db mouse, a model of type 2 diabetes that develops overt nephropathy. Diabetic db/db mice and nondiabetic db/m littermates were treated intraperitoneally with alphaT or control IgG, 300 microgram three times per week for 8 wk. Treatment with alphaT, but not with IgG, significantly decreased the plasma TGF-beta1 concentration without decreasing the plasma glucose concentration. The IgG-treated db/db mice developed albuminuria, renal insufficiency, and glomerular mesangial matrix expansion associated with increased renal mRNAs encoding alpha1(IV) collagen and fibronectin. On the other hand, treatment with alphaT completely prevented the increase in plasma creatinine concentration, the decrease in urinary creatinine clearance, and the expansion of mesangial matrix in db/db mice. The increase in renal matrix mRNAs was substantially attenuated, but the excretion of urinary albumin factored for creatinine clearance was not significantly affected by alphaT treatment. We conclude that chronic inhibition of the biologic actions of TGF-beta with a neutralizing monoclonal antibody in db/db mice prevents the glomerulosclerosis and renal insufficiency resulting from type 2 diabetes.

Animals↗

PubMed2002

Molecular mechanism involved in matrix dependent upregulation of matrix metalloproteinases in monocyte/macrophage.

Production of macrophage specific matrix metalloproteinases (MMPs) by monocyte/macrophage (mo/mphi) maintained in vitro on matrix protein substrata has been examined to study the mechanism of matrix protein dependent upregulation of macrophage specific activity. Using specific blocking reagents we have found that interaction of peripheral blood mononuclear cells (PBMC) with extracellular matrix components is crucial for its differentiation to macrophages. Multiwell zymography has shown that production of MMPs was significantly inhibited in cells maintained on fibronectin (FN) pretreated with antibodies to alpha(5), beta(1) integrins and synthetic peptide RGDS. Further, quantification by ELISA showed a significant inhibition in MMP production in cells pretreated with these blocking reagents. Genistein, a non-specific inhibitor of tyrosine kinases, significantly reduced production of MMPs in cells maintained on FN and collagen type IV (COL IV). Immunoblotting analysis has shown that tyrosine phosphorylation occurs in 30 min and two proteins of approximately 115 and approximately 72 kDa are being phosphorylated upon PBMC-FN interaction. These results indicate that integrin mediated downstream signalling involving tyrosine phosphorylation is required for mediating intracellular events associated with differentiation of monocytes to macrophages.

Cell Differentiation↗

PubMed2004

Activities of the matrix metalloproteinase stromelysin-2 (MMP-10) in matrix degradation and keratinocyte organization in wounded skin.

The matrix metalloproteinase stromelysin-2 is expressed in keratinocytes of the epithelial tongue of skin wounds, suggesting a role in keratinocyte migration. Here, we show that stromelysin-2 enhances migration of cultured keratinocytes. To gain insight into the in vivo activities of stromelysin-2 in epithelial repair, we generated transgenic mice expressing a constitutively active stromelysin-2 mutant in keratinocytes. These animals had no alterations in skin architecture, and the healing rate of skin wounds was normal. Histologically, however, we found abnormalities in the organization of the wound epithelium. Keratinocytes at the migrating epidermal tip were scattered in most sections of mice with high expression level, and there was a reduced deposition of new matrix. In particular, the staining pattern of laminin-5 at the wound site was altered. This may be due to proteolytic processing of laminin-5 by stromelysin-2, because degradation of laminin-5 by this enzyme was observed in vitro. The inappropriate matrix contact of keratinocytes was accompanied by aberrant localization of beta1-integrins and phosphorylated focal adhesion kinase, as well as by increased apoptosis of wound keratinocytes. These results suggest that a tightly regulated expression level of stromelysin-2 is required for limited matrix degradation at the wound site, thereby controlling keratinocyte migration.

Animals↗

PubMed2002

Matrix metalloproteinase activity, bone matrix turnover, and tumor cell proliferation in prostate cancer bone metastasis.

BACKGROUND: The metastasis of prostate cancer to bone is associated with a substantial increase in bone matrix turnover. Matrix metalloproteinases (MMPs) play roles in both normal bone remodeling and invasion and metastasis of prostate cancer. This study was designed to determine the role of MMP activity in prostate cancer that has metastasized to bone. METHODS: Single human fetal bone fragments were implanted subcutaneously in immunodeficient mice. Four weeks later, PC3 human prostate cancer cells were injected directly into some of the implants, and daily treatment was begun with batimastat (a broad-spectrum MMP inhibitor). There were six mice (i.e., six implants) in each of four experimental arms: bone alone with and without batimastat and bone injected with PC3 cells with and without batimastat. Bone implants were harvested after 14 days of treatment and analyzed for MMP expression, bone histomorphometry, osteoclast counts, blood vessel density, and tumor cell proliferation and apoptosis. Complementary data were obtained from bone biopsy samples from patients and a bone organ coculture system. All statistical tests were two-sided. RESULTS: MMPs were detected in tumor and stromal cells of clinical specimens and experimental bone implants. In vivo, MMP inhibition reduced the number of osteoclasts per millimeter in PC3-injected implants-from 8.2 (95% confidence interval [CI] = 7.9 to 8.5) to 3.0 (95% CI = 2.3 to 3.7) (P =.006). In addition, it prevented degradation of marrow trabeculae within the bone implants (cross-sectional area of implant occupied by mineralized trabeculae: untreated implant = 29.1% [95% CI = 27.1% to 31.1%], PC3-injected implant = 14.0% [95% CI = 10.9% to 17.1%] [P =.005 versus untreated], and batimastat-treated PC3-injected implant = 27.2% [95% CI = 22.4% to 32.0%] [P =.03 versus PC3 injected alone]). MMP inhibition reduced proliferating tumor cells from 20.8% (95% CI = 19.9% to 21.7%) to 7.4% (95% CI = 5.2% to 9.6%) (P =.006), without affecting angiogenesis or apoptosis. In vitro, MMP inhibition had no toxic effect on PC3 cells but prevented calcium release from bone fragments cocultured with PC3 cells. CONCLUSIONS: MMP activity appears to play an important role in bone matrix turnover when prostate cancer cells are present in bone. Bone matrix turnover and metastatic tumor growth appear to be involved in a mutually supportive cycle that is disrupted by MMP inhibition.

Animals↗

PubMed2007

Relationship between matrix metalloproteinases MMP-2, MMP-9, tissue inhibitor of matrix metalloproteinases-1 and IL-5, IL-8 in nasal polyps.

BACKGROUND: Nasal polyps (NP), a subgroup of chronic rhinosinusitis, are characterized by interleukin 5 (IL-5) mediated infiltration of eosinophils in sinus mucosa, leading to pseudostratified ciliated columnar epithelium, thickening of the epithelial basement membrane and tissue edema. Matrix metalloproteinases (MMP) constitute a large group of Zn2+ dependent endopeptidases with the ability to degrade extracellular matrix and are possibly responsible for the development of tissue edema in chronic sinusitis. OBJECTIVE: The aim of this study was to determine the expression of MMP-2, MMP-9 and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) mRNA and to locate the distribution of MMP-2, MMP-9 and TIMP-1 by immunohistochemistry in ethmoid sinus mucosa in NP. Furthermore the correlation between IL-5 or IL-8 and MMP-2, MMP-9 or TIMP-1 is examined. METHODS: Nasal polyps of 33 patients and 18 specimens of inferior turbinate mucosa were examined by real time RT-PCR for MMP-2, MMP-9, TIMP-1, IL-5 and IL-8 mRNA expression. Immunohistochemical labeling for MMP-2, MMP-9 and TIMP-1 was performed. RESULTS: Differences between both locations were detectable for MMP-9 (P < 0.001) and IL-5 (P=0.003) but not for MMP-2 (P=0.278), TIMP-1 (P=0.515) and IL-8 (P=0.386). Correlation was detected only between TIMP-1 and IL-5 (r=0.422, P =0.014). Cytoplasmic staining of MMP-2 was present in the apical part of the ciliated cells, submucosal glands and in smooth muscle cells. Matrix metalloproteinase-9 was expressed in surface epithelium, in seromucous glands and in polymorphonuclear cells. CONCLUSIONS: Expression of MMP-9 and IL-5 mRNA are associated with NP. The correlation between IL-5 and TIMP-1 indicates the role of TIMP-1 in maintaining the homeostasis in NP.

Adult↗

PubMed1998

Matrix metalloproteinase-2 production and its binding to the matrix are increased in abdominal aortic aneurysms.

Degradation of the elastic media is a hallmark of abdominal aortic aneurysms (AAAs). We examined the expression of 2 elastolytic matrix metalloproteinases (MMPs), MMP-2 and MMP-9, in AAA aortic tissues compared with those from atherosclerotic occlusive disease (AOD) and nondiseased control tissues. Quantitative competitive reverse transcription-polymerase chain reaction and gelatin zymography showed increased MMP-9 mRNA and protein in both AAA and AOD tissues compared with those in control tissue, but there was no significant difference between AAA and AOD. In contrast, MMP-2 mRNA and protein levels were significantly higher in AAA than in AOD or control tissues. Sequential extraction of the MMPs from the aortic tissue with a physiological salt solution, 2% dimethylsulfoxide (DMSO), and 10 mol/L urea showed that large amounts of MMP-2 and MMP-9 were bound to the matrix. The most conspicuous finding was that the levels of MMP-2 were significantly elevated in the DMSO fraction in AAA tissues compared with AOD and control tissues. In addition, a large portion of MMP-2 found in the DMSO and urea fractions was in the active 62-kDa form, indicating that the precursor of MMP-2 in AAA is largely activated locally and binds to the tissue matrix tightly. By immunolocalization, MMP-9 was found to be primarily produced by macrophages and MMP-2 by mesenchymal cells. The production of MMP-2 was prominent when mesenchymal cells were surrounded by inflammatory cells, suggesting paracrine modulation of MMP-2 expression in AAAs. These observations emphasize that MMP-2 participates in the progression of AAAs by degrading aortic tissue matrix components.

Aged↗

PubMed2005

The central role of vascular extracellular matrix and basement membrane remodeling in metabolic syndrome and type 2 diabetes: the matrix preloaded.

The vascular endothelial basement membrane and extra cellular matrix is a compilation of different macromolecules organized by physical entanglements, opposing ionic charges, chemical covalent bonding, and cross-linking into a biomechanically active polymer. These matrices provide a gel-like form and scaffolding structure with regional tensile strength provided by collagens, elasticity by elastins, adhesiveness by structural glycoproteins, compressibility by proteoglycans--hyaluronans, and communicability by a family of integrins, which exchanges information between cells and between cells and the extracellular matrix of vascular tissues. Each component of the extracellular matrix and specifically the capillary basement membrane possesses unique structural properties and interactions with one another, which determine the separate and combined roles in the multiple diabetic complications or diabetic opathies. Metabolic syndrome, prediabetes, type 2 diabetes mellitus, and their parallel companion (atheroscleropathy) are associated with multiple metabolic toxicities and chronic injurious stimuli. The adaptable quality of a matrix or form genetically preloaded with the necessary information to communicate and respond to an ever-changing environment, which supports the interstitium, capillary and arterial vessel wall is individually examined.

Basement Membrane↗

PubMed2001

Impact of mutations of cartilage matrix genes on matrix structure, gene activity and chondrogenesis.

OBJECTIVE: Chondrocytes in the growth plate at different stages of differentiation synthesize characteristic extracellular matrix (ECM) components. Mutations in some ECM genes result in chondrodysplasia in humans and mice. We aimed to evaluate the impact of loss- and gain-of-function mutations of ECM genes on matrix structure, gene expression and formation of the growth plate. DESIGN: We review information on the impact of deficiencies in proteoglycans, and types X and II collagens on skeletal development. Additionally, we compare the impact of a glycine904 to cysteine (G904C) mutation in the triple helical coding domain of mouse Col2a1 with two previously reported Col2a1 mutations (exon7 deletion (Del1) and G85C). The G904C Col2a1 gene was introduced as a transgene into mice. Transgenic newborn mice were examined for skeletal development. The histology of the epiphyseal cartilage and the growth plate, and the ultrastructure of chondrocytes and collagen fibrillar morphology in the ECM were studied in 18.5-day transgenic and wild-type fetuses. The distribution of the mRNAs for Col2a1, Col11a1, Col9a1, Matn1, Agc and Ihh in the growth plate of 18.5-day G904C/G904C and wild type fetuses were compared by in situ hybridization. RESULTS: Heterozygous transgenic mice harbouring five copies of the G904C Col2a1 transgene developed skeletal abnormalities and dwarfism. Homozygous G904C/G904C mice died at birth, showing cleft palate, disrupted zonation of chondrocytes and reduction of the zone of hypertrophic chondrocytes. Fewer collagen fibrils were found in ECM of the cartilage. Rough endoplasmic reticulum of the chondrocytes of G904C/+ and G904C/G904C mice was distended. In G904C/G904C mutant mice, Agc gene activity was extended to the hypertrophic zone. Expression of the other genes studied was unchanged. Calcified materials that were not found normally in the maturing and only at low abundance in the hypertrophic zones of the wild type growth plate, were present in these zones in G904C/G904C mice. Despite phenotypic similarities for the G904C and Del1 mice, reduced expression of types I, II, IX, X collagens and aggrecan were reported for the latter mutation. Changes in gene activity and matrix organization in the growth plate also accompanied deficiencies in aggrecan, perlecan and collagen II. CONCLUSIONS: The data suggest that a single amino acid alteration in collagen II could lead to skeletal abnormalities through multiple secondary effects on the synthesis and assembly of ECM components. The functional impact of mutations of ECM genes reveals that chondrodysplasia is caused not just by the formation of abnormal matrix molecules, but that the alteration of one ECM component may lead to a cascade of disruption of other gene activities in chondrocytes which collectively contribute to the pathological changes in the architecture of the growth plate.

Aggrecans↗

PubMed1995

Leukemic cells (HL-60) produce a novel extracellular matrix-degrading proteinase that is not inhibited by tissue inhibitors of matrix metalloproteinases (TIMPs).

In addition to the known 94-kd gelatinase (matrix metalloproteinase 9, MMP-9), HL-60 leukemia cells release a hither-to undescribed 45-kd metalloproteinase into the culture medium. This enzyme cleaves the synthetic substrate Pro-Gln-Gly-Ile-Ala-Gly-Gln-Arg, which represents the cleavage site for collagenases in collagen type I not between isoleucine and alanine--the typical cleavage site for collagenases--but between alanine and glycine. The enzymatic activity was purified through a combination of zinc-chelate-Sepharose column chromatography, precipitation with Fractogel TSK-AF Red and gelatin-Sepharose, and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Microsequence analysis of the NH2-terminus of the purified 45-kd proteinase revealed the sequence Asp-Ile-Ser-Lys-Tyr-Thr-Thr-Thr-, which could not be found in other proteins when searched in several protein data bases. Incubation of the enzyme immobilized on nitrocellulose membranes with polyclonal antibodies to collagenase and stromelysin or gelatinases revealed no cross-reactivity. The proteolytic activity was not increased by treatment with trypsin, 8M urea, acid, or organomercurials. The proteinase, which was inhibited by chemical inhibitors of metalloproteinases, such as phenanthrolene or EDTA, is able to degrade several matrix constituents, such as collagen type IV, fibronectin, gelatin, and proteoglycans. In contrast to all known MMPs, the proteolytic activity of the 45-kd enzyme was not abolished upon incubation with recombinant tissue inhibitors of matrix metalloproteinases (TIMP) 1 or 2. Thus, the novel enzyme may influence extracellular matrix (ECM) turnover in vivo because its activity is not influenced by specific inhibitors of MMPs.

Amino Acid Sequence↗

PubMedDate not supplied

Mesangial cell-matrix interactions: modulation of matrix expression in mesangial cells by extracellular matrices.

Aberrant extracellular matrices (ECMs) observed in mesangial areas during the progression of glomerulonephropathy could be produced by mesangial cells (MCs), interacting with altered ECM components, under the influence of various mediators. We studied the interaction between MCs and ECMs, especially focusing on matrix expression of MCs in contact with ECMs. We analyzed mRNA expression and protein synthesis of ECM components by cultured rat MCs which were plated on different types of ECMs, basement membrane-type matrix (BMM), type IV collagen and type I collagen. The level of mRNA for ECM components (alpha 1 type I collagen, alpha 1 type IV collagen, fibronectin and laminin B2) increased in MCs on the two types of collagen compared with BMM. The relative increase of alpha 1 type I collagen mRNA expression in MCs on type I collagen was greater than that of alpha 1 type IV collagen expression. At the protein level, type I collagen production by MCs on coated type I collagen showed a 2.2-fold increase relative to that on BMM. MCs on type IV collagen produced it at an intermediate level. The phenomena were not associated with differences of proliferative activity, but were accompanied by minor morphological differences. These results indicate that ECMs can modulate the phenotype of MCs in terms of matrix expression and suggest that MC-matrix interaction may in part contribute to abnormal ECM accumulation in diseased glomeruli.

Animals↗

PubMed1998

Remodeling of collagen matrix by human tumor cells requires activation and cell surface association of matrix metalloproteinase-2.

We assessed the functional significance of tumor cell-associated matrix metalloproteinase (MMP)-2 in extracellular matrix remodeling compared with that of the soluble enzyme by evaluating the contraction of three-dimensional collagen lattices by human glioma U251.3 and fibrosarcoma HT-1080 cell lines. In this model, the constitutive synthesis and activation of the MMP-2 proenzyme were modulated by stable transfections of tumor cells with cDNA encoding membrane type 1-MMP (MT1-MMP). The efficiency of transfected cells in contracting collagen lattices was shown to be dependent on the MT1-MMP-mediated activation of MMP-2 accompanied by cell surface association of activated MMP-2, on the cell-matrix interactions controlled by collagen-specific integrins, and on the integrity of actin and microtubule cytoskeletons. Each one of these mechanisms was essential but was not sufficient by itself in accomplishing gel contraction by MT1-MMP-transfected cells. Both MMP-2 activation and gel contraction by transfected glioma cells were inhibited by tissue inhibitor of metalloproteinase (TIMP)-2 and the recombinant COOH-terminal domain of MMP-2. However, the kinetics and mechanisms of their inhibitory effects were different, because TIMP-2 and the COOH-terminal domain of MMP-2 preferentially inhibited the MT1-MMP-dependent and autocatalytic steps of MMP-2 activation, respectively. By contrast, TIMP-1, an efficient inhibitor of soluble MMP-2 activity, failed to affect gel contraction. In addition, soluble MMP-2 activated by either organomercurials or cells was not able to induce the contraction of collagen lattices when added to transfected cells. Therefore, soluble activated MMP-2, sensitive to TIMP-1 inhibition, does not mediate collagen gel contraction by tumor cells, whereas the activity of cell surface-associated MMP-2 plays a critical role in remodeling of the extracellular matrix in vitro. These mechanisms of functional and spatial regulation of MMP-2 may also be applicable to different aspects of tissue reorganization in vivo, including cell migration and invasion, angiogenesis, and wound healing.

Collagen↗

PubMed1998

Matrix metalloproteinase-mediated extracellular matrix protein degradation in human pulmonary emphysema.

The aim of this study was to investigate the extracellular degrading proteolytic cascade proteins referred to as matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9, membrane-type matrix metalloproteinase-1 (MT1-MMP), tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), TIMP-2, neutrophil elastase, and alpha1-antitrypsin in human pulmonary emphysema. Localization of MMP-1, MMP-2, MMP-8, MMP-9, MT1-MMP, TIMP-1, and TIMP-2 was verified by immunohistochemical analysis. The results of our study indicated that the immunoreactivity of MMP-1, MMP-8, MMP-9, and TIMP-1 was absent, whereas MT1-MMP and MMP-2 were mainly observed in pneumocytes, fibroblasts, and alveolar macrophages. Although MT1-MMP and MMP-2 were observed both in emphysematous and normal lung tissue, these immunoreactivities were intense in the emphysematous samples. The presence of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 was confirmed at mRNA level by reverse transcription-PCR analysis and enzyme immunoassay (EIA). However, the only statistical difference that was observed was in MMP-2 and MMP-9 (MMP-2: emphysematous samples, 19.1+/-2.1 versus control samples, 5.2+/-0.60 microg/g protein, p < 0.05; MMP-9: emphysematous samples, 18.4+/-5.6 versus control samples, 8.1+/-2.7 microg/g protein, p < 0.05). Results of the neutrophil elastase as analyzed by EIA, and alpha1-antitrypsin levels as detected by laser nephelometric immunoassay, indicated no statistical difference between the emphysematous and control groups. In addition to the presence of mRNA levels, the level of MT1-MMP according to immunoblot analysis increased in the emphysematous samples. Gelatin zymographic analysis confirmed the presence of both pro and active forms of MMP-2, and the increased ratio of the active form of MMP-2 in emphysematous samples (25.9%+/-2.0% versus 11.2%+/-3.3%, p < 0.05), indicated in situ activation of MMP-2 by MT1-MMP. Elastin zymographic analysis showed elastolytic activity by MMP-2 and MMP-9 but not the reported band of macrophage metalloelastase (MMP-12). The data suggest that the MT1-MMP/MMP-2/TIMP-2 system plays a significant role in the MMP-mediated extracellular matrix degradation and tissue remodeling of emphysematous lungs, and thus may contribute to the weakening of lung parenchyma and lead to the formation of emphysema.

Aged↗

PubMed1996

Secretion of matrix metalloproteinase-2 (72 kD gelatinase/type IV collagenase = gelatinase A) by malignant human glioma cell lines: implications for the growth and cellular invasion of the extracellular matrix.

Human glioma cells (T98G and A172 cell lines) were cultured on various extracellular matrix (ECM) components including type I, IV and V collagens, fibronectin, laminin, and reconstituted basement membrane (Matrigel), and the role of matrix metalloproteinases (MMPs) in their growth and invasion was examined. T98G glioma cells grew well on these ECM components and invaded the reconstituted basement membrane. In contrast, A172 glioma cells showed growth inhibition on collagen types IV and V and Matrigel without invasion of the Matrigel. Gelatin zymography and enzyme immunoassays demonstrated that T98G glioma cells, but not A172 cells, secrete a large amount of matrix metalloproteinase-2 (MMP-2, 72 kD gelatinase/type IV collagenase = gelatinase A), and this was confirmed by immunoblotting and immunohistochemistry. Of the two different tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), T98G cells produced only TIMP-1 during culture on Matrigel, whereas A172 cells secreted both. Although both human recombinant TIMP-1 and TIMP-2 stimulated T98G cell growth slightly on Matrigel, the in vitro invasiveness was significantly reduced by only recombinant TIMP-2. These results suggest that MMP-2 plays an important role in the ECM invasion of T98G human glioma cells in vitro.

Brain Neoplasms↗

PubMed2000

Collagen and elastin degradation by matrix metalloproteinases and tissue inhibitors of matrix metalloproteinase in aortic dissection.

The degradation of collagen fibrils and elastic fibers in 21 cases of acute aortic dissection (AD) was ultrastructurally and immunohistochemically investigated; and the expression of the catabolic matrix metalloproteinases (MMPs)-1, -2, -3, and -9 and their inhibitors, the tissue inhibitors of matrix metalloproteinase (TIMPs)-1 and -2, was studied. The features of the entry site of the dissection (ES; 21 ascending aortas) were compared with those of fully remote sites (RS; 19 nondissected abdominal aortas) and the ascending aortas from 10 control cases. By electron microscopy, the medial layer at the ES and adjacent intact aortic wall demonstrated spirally thickened collagen fibrils with a typical banding pattern that were almost always colocalized with elastic lamellae, which often exhibited attenuation, fragmentation, or disruption. In addition, the basement membrane surrounding the smooth muscle cells (SMCs) comprising the media was frequently thinned or lost at the ES. These findings were rarely seen at the RS or in the aortas of controls. Immunohistochemically, the expression of MMP-1 was significantly in the cytoplasm of SMCs of both the intima and media at the ES and adjacent intact wall, and significant expression of MMP-2 and -9 was found in SMCs of the intima compared with the RS and controls. Significant expression of TIMP-1 and -2 was demonstrated in the cytoplasm of SMCs at the ES and adjacent intact wall compared with that at the RS and the control specimens. These findings suggest that the degradation of proteins associated with fibrosis and the occurrence of AD are not merely coincident, but rather that AD is induced by alterations of the extracellular matrix caused by changes of SMCs at a segment of the ascending aorta made vulnerable through hemodynamic stress, especially that caused by hypertension.

Adult↗

PubMed2006

Interstitial fibrosis in the heart: differences in extracellular matrix proteins and matrix metalloproteinases in end-stage dilated, ischaemic and valvular cardiomyopathy.

AIMS: To investigate whether or not there are differences in the distribution of extracellular matrix (ECM) proteins and matrix metalloproteinases (MMPs) in end-stage heart failure underlying different cardiomyopathies. METHODS AND RESULTS: Thirty-nine explanted human hearts were investigated: 15 with dilated cardiomyopathy (DCM), 17 with ischaemic cardiomyopathy (ICM) and seven with valvular cardiomyopathy (VCM). Transmural samples from four different sites were investigated. Frozen sections were processed for immunohistochemistry for collagens type I, III, IV, laminin and fibronectin, as well as MMP-1, -2 and -9. Volume densities were determined. All ECM components were expressed more frequently in DCM than in ICM. Comparing ICM with VCM, all proteins were found more frequently in VCM than in ICM except for type III collagen, which was significantly more frequent in ICM. Comparing DCM and VCM, VCM showed significantly higher volume densities for type III collagen and laminin. MMPs showed only slight variations between the cardiomyopathies. CONCLUSION: The distribution of ECM proteins differs between DCM, ICM and VCM, which suggests that they can be morphologically discriminated by interstitial fibrosis, especially by their expression of matrix proteins.

Adult↗