M Roderfeld

Inhibition of hepatic fibrogenesis by matrix metalloproteinase-9 mutants in mice

Tissue inhibitor of metalloproteinases‐1 (TIMP‐1) plays a crucial role in the pathogenesis of hepatic fibrosis and thus may represent an important therapeutic target in the design of anti‐fibrotic strategies for chronic liver disease. We present an innovative therapy based on the assignment of inactivated enzymes acting as scavengers for TIMP‐1. Hepatic fibrosis was induced in BALB/c mice by repetitive intraperitoneal CCl4 injection. The animals were treated with proteolytic inactive matrix metalloproteinase‐9 mutants (E402Q, H401A, E402H/H411E) using adenovirus‐mediated gene transfer. Application of these MMP‐9 mutants inhibited fibrogenesis, which was indicated by decreasing portal and periportal accumulation of collagen. Total hydroxyproline of liver tissue, the morphometric stage of fibrosis as well as mRNA expression of marker proteins for hepatic fibrosis in livers of E402Qand H401A‐treated mice were significantly reduced. MMP‐9 mutants suppressed transdifferentiation of hepatic stellate cells to the myofibroblast like phenotype in vitro and in vivo. Moreover, adenoviral application of the mutants MMP‐9‐H401A and ‐E402Q led to increased apoptosis of activated hepatic stellate cells, thought to be the main promoters of hepatic fibrosis. Application of MMP‐9 mutants as TIMP‐1 scavengers may provide a new therapeutic strategy for hepatic fibrosis.—Roderfeld, M., Weiskirchen, R., Wagner, S., Berres, M.‐L., Henkel, C., Grötzinger, J., Gressner, A. M., Matern, S., Roeb, E. Inhibition of hepatic fibrogenesis by matrix metalloproteinase‐9 mutants in mice. FASEB J. 20, 444–454 (2006)

Matrix Metalloproteinase-9 Promotes Chronic Lymphocytic Leukemia B Cell Survival through Its Hemopexin Domain

Matrix metalloproteinase-9 (MMP-9) is the major MMP produced by B-CLL cells and contributes to their tissue infiltration by degrading extracellular and membrane-anchored substrates. Here we describe a different function for MMP-9 in B-CLL, which involves the hemopexin domain rather than its catalytic function. Binding of soluble or immobilized (pro)MMP-9, a catalytically inactive proMMP-9 mutant, or the MMP-9 hemopexin domain to its docking receptors alpha4beta1 integrin and CD44v, induces an intracellular signaling pathway that prevents B-CLL apoptosis. This pathway is induced in all B-CLL cases, is active in B-CLL lymphoid tissues, and consists of Lyn activation, STAT3 phosphorylation, and Mcl-1 upregulation. Our results establish that MMP/receptor binding induces intracellular survival signals and highlight the role of (pro)MMP-9 in B-CLL pathogenesis.

Activation of hepatic stellate cells is associated with cytokine expression in thioacetamide-induced hepatic fibrosis in mice

The pathophysiological mechanisms of thioacetamide (TAA)-induced hepatic fibrogenesis are not yet fully understood. In particular, the role of hepatic stellate cells (HSCs) remains unclear. We therefore examined proliferation and transdifferentiation of HSC as well as the underlying molecular mechanisms in TAA-induced fibrosis. Hepatic fibrogenesis was induced in mice by addition of TAA to drinking water. Liver damage was determined by assessment of alanine aminotransferase and aspartate aminotransferase levels, and measurement of collagen deposition. Additionally, expression patterns of α-smooth muscle actin, glial fibrillary acidic protein (GFAP, specific hepatic biomarker for HSC), cysteine- and glycine-rich protein 2 (CRP2, specific marker of HSC transdifferentiation), tissue inhibitor of metalloproteinases-1, matrix metalloproteinase-9 (MMP-9), interleukins (IL-1β, IL-6), platelet-derived growth factors (PDGF-B, PDGF-D) , tumor necrosis factor (TNF)-α, and (transforming growth factor (TGF)-β1 were assessed by real-time PCR. Transcription of GFAP and CRP2 were transiently upregulated during TAA-induced fibrogenesis (punctum maxima (p.m.) week 10 for GFAP and week 14 for CRP2). Similar transient expression patterns were demonstrated for IL-1β, IL-6, TGF-β1, and PDGF-B (p.m. week 12) whereas TNF-α and PDGF-D continuously increased with ongoing liver injury. In particular, not only neutrophil granulocytes, but also macrophages and leukocytes served as a major source for MMP-9 expression. GFAP and CRP2 expression patterns demonstrated transiently increased HSC-activation during TAA-induced hepatic fibrogenesis. The rate of increase of transcription of GFAP correlated best with PDGF-B, whereas CRP2 levels correlated with PDGF-B, PDGF-D, and IL-1β expression. This study demonstrates for the first time that transiently increased activation patterns of HSC are observed in toxically induced hepatic fibrosis. Thus, TAA in drinking water is an effective and elegant model to induce reproducible states of liver fibrosis without parenchymal damage in mice.

Bone marrow transplantation demonstrates medullar origin of CD34+ fibrocytes and ameliorates hepatic fibrosis in Abcb4−/− mice

Bone marrow (BM)‐derived stem cells and CD34+ fibrocytes are associated with fibrogenesis in several organs. In an Abcb4−/− mouse model for sclerosing cholangitis alpha‐smooth muscle actin‐positive (α‐SMA+) myofibroblasts are thought to play a pivotal role in hepatic fibrogenesis. The aim of this study was 2‐fold: (1) to demonstrate that the origin of an important fibrogenetic cell population is the BM; and (2) to investigate whether transplantation of BM (BM‐Tx) affects liver function, staging, and grading. Surrogate markers for fibrogenesis and regulation of hepatic stellate cells (HSC) as well as progenitor‐cell‐derived fibrocytes in liver tissue were analyzed by quantitative real‐time polymerase chain reaction (PCR) and immunohistology. After lethal irradiation of recipient mice, BM‐Tx was carried out by way of tail vein injection of BM cells from marker protein donors (green fluorescent protein, GFP+) or Abcb4−/− mice as control (syngeneic Tx). Parameters of liver function were assessed serologically and histologically. Activated HSC of α‐SMA+/CRP2+ phenotype were expressed in ≈50% of proliferating bile ducts, whereas fibrotic liver parenchyma showed no expression thereof. Epithelial mesenchymal transfer (EMT) was visualized in the areas of proliferating bile ducts. The hematopoietic origin of CD34+ fibrocytes was demonstrated immunohistologically in livers of BM chimeric mice. These CD34+ cells infiltrated hepatic lobules from portal fields and developed a desmin+ phenotype expressing collagen type I in fibrotic parenchyma as well as in vitro after isolation by magnetic cell separation. Transplantation of GFP+/Abcb4+ BM improved liver function and staging compared with sham transplantation, but no significant differences were noticed among allogeneic and syngeneic Tx. Conclusion: The present study is the first to identify that both BM‐derived fibrocytes and HSC are involved in biliary fibrogenesis in Abcb4−/− mice. Our data suggest that changes in immunity subsequent to BM‐Tx may alter hepatic fibrosis. (HEPATOLOGY 2009.)

Enhanced expression of MMP-7 and MMP-13 in inflammatory bowel disease: a precancerous potential?

&NA; Matrix metalloproteinases (MMPs) are responsible for the turnover and degradation of extracellular matrix. They play a crucial role in the growth and migration of colorectal carcinoma cells. Colorectal carcinomas are characterized by enhanced expression of MMP‐2, MMP‐9, MMP‐7, and MMP‐13. The aim of this study was to determine the expression levels of MMP‐2, MMP‐9, MMP‐7, MMP‐13, and MMP‐14 and their specific inhibitor TIMP‐1 in inflammatory bowel diseases and precancerous lesions of the colon, i.e., Crohns disease and ulcerative colitis, and in adenomatous polyps (APs) for comparison. Biopsy samples of pathological and healthy tissue were obtained from 40 patients with inflammatory bowel disease (ulcerative colitis, n = 17; Crohns disease, n = 23) and from 19 patients with APs. mRNA was measured by quantitative real‐time polymerase chain reaction to study MMP and TIMP‐1 gene expression in both pathological and normal mucosal specimens. For MMP‐2, MMP‐9, and TIMP‐1, protein expression also was quantified with sandwich enzyme‐linked immunosorbent assay. In biopsy specimens of Crohns disease and ulcerative colitis, significantly increased levels of MMP‐2, MMP‐7, and MMP‐13 mRNA were found. MMP‐2 and MMP‐9 showed enhanced secretion on the protein level. AP revealed an increased transcription of MMP‐7 and MMP‐13 genes. MMP‐14 mRNA was decreased in APs. MMPs, especially MMP‐7 and MMP‐13, which are expressed primarily on the tumor cell surface, are elevated in inflammatory bowel disease, which may have more chance to evolve into malignancy than normal tissue. In APs, increased expression of MMP‐7 and MMP‐13 may serve as an early indicator for colorectal carcinogenesis.

Serum matrix metalloproteinases in adult CF patients: Relation to pulmonary exacerbation

BACKGROUND Matrix metalloproteinases (MMPs) virtually degrade all components of the extracellular matrix and are mainly expressed in tissues following inflammation or remodeling. Increased expression of certain MMPs in sputum and bronchoalveolar lavage of patients with cystic fibrosis (CF) is related to impaired lung function. We investigated whether a panel of serum MMPs is associated with both, impairment of pulmonary function and occurrence of pulmonary exacerbations (PEx) in adult patients with CF. METHODS Serum concentrations of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-12, MMP-13, and TIMP-1 were determined by ELISA in 54 adult CF patients. PEx was defined based on a score established by Rosenfeld in 2001. MMP-1, MMP-8, MMP-9 and TIMP-1 were assessed in 7 CF patients with PEx before and after systemic antibiotic therapy. RESULTS Of the 54 CF patients, PEx was diagnosed in 16 different CF patients. Compared to healthy controls, MMP-1, MMP-8, and MMP-9, serum levels were elevated in CF patients and correlated with PEx. MMP-8 expression was associated with impaired lung function. For MMP-2, we observed a decreased expression and an association of MMP-2 decline with PEx. Antibiotic treatment of CF patients with PEx led to a decrease of MMP-1, MMP-8 and active MMP-9 protein concentration. CONCLUSIONS Increased serum expression of certain MMPs is associated with occurrence of PEx and impaired lung function in CF. Hence, these MMPs might serve as surrogate markers for PEx.

Cytokine blockade inhibits hepatic tissue inhibitor of metalloproteinase‐1 expression and up‐regulates matrix metalloproteinase‐9 in toxic liver injury

Abstract: Background: Tissue inhibitor of metalloproteinases (TIMP)‐1, the most important endogenous inhibitor of matrix metalloproteinases, plays a pivotal role in the pathogenesis of liver fibrosis and may represent an effective therapeutic target in the design of antifibrotic strategies for chronic liver diseases.

Cellular sources of MMP-7, MMP-13 and MMP-28 in ulcerative colitis.

Abstract Objective. Matrix metalloproteinases (MMPs) are considered the predominant proteases in the pathogenesis of mucosal ulcerations associated with inflammatory bowel disease (IBD). Whether the malignancy associated MMP-7 and MMP-13 or the recently cloned MMP-28 convey a certain meaning for intestinal homeostasis and pathogenesis of IBD is currently unknown. We therefore set off to analyze regulation patterns and cellular origins of these MMPs in mucosal tissues of patients with ulcerative colitis (UC). Material and methods. Biopsy samples of affected and healthy tissues were obtained from 35 Norwegian patients with UC. RNA was quantified by quantitative real-time polymerase chain reaction to study MMP gene expression in both pathological and healthy mucosal specimens. Cellular origins were determined by immunohistology using surrogate markers for inflammation, neovascularization, and epithelial structures. Protein expression of MMP-7 and MMP-13 was quantified using enzyme-linked immunosorbent assay. Results. MMP-7 and MMP-13 gene expression was significantly increased in UC affected colonic mucosa whereas MMP-28 showed a decreased expression in inflamed mucosa. Endothelial cells and infiltrating leukocytes were identified as the major cellular sources of MMP-7 and MMP-13 in UC. Enterocytes represented the major cellular source of MMP-28 in healthy and inflamed mucosa. Conclusions. MMP-7 and MMP-13 expression in inflammatory and endothelial cells indicate a role of these MMPs for both colitis associated neoangiogenesis and inflammatory changes. Decreased MMP-28 expression in UC is most likely the result of colitis associated epithelial destruction and loss of cryptal architecture.

Latent MMP-9 is bound to TIMP-1 before secretion

Abstract Expression patterns of matrix metalloproteinase-9 (MMP-9) and its specific inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1), are closely correlated with physiological and pathological processes characterized by the degradation and accumulation of the extracellular matrix (ECM). Both, activated MMP-9 and pro-MMP-9 can bind to TIMP-1, and most cell types secrete MMP-9 in complex with TIMP-1. Utilizing immunofluorescence, we observed intracellular co-localization of MMP-9 and TIMP-1 in stimulated human fibrosarcoma cells. In the present study we searched for the origin of the complex formation between the latent enzyme and its specific inhibitor on a subcellular level. Fluorescence resonance energy transfer (FRET) between the fluorescently labeled enzyme and its inhibitor in co-transfected cells were measured. MMP-9 and TIMP-1 were fused to cyan (CFP) and yellow (YFP) variants of the green fluorescent protein and transiently expressed in human hepatoma cells. The intracellular distribution of fluorescently labeled TIMP-1 and MMP-9 was analyzed by confocal laser scanning microscopy. Intracellular complex formation in the Golgi apparatus was verified, demonstrating FRET between MMP-9-CFP and TIMP-1-YFP. Our data provide evidence that the proMMP-9-TIMP-1 complex is already present in the Golgi apparatus. This may be of significance for a number of intracellular and extracellular biochemical processes involving proMMP-9. However, the magnitude and functional relevance of this finding remain unknown.

Matrix metalloproteinase-19 inhibits growth of endothelial cells by generating angiostatin-like fragments from plasminogen

BackgroundAngiogenesis is the process of forming new blood vessels from existing ones and requires degradation of the vascular basement membrane and remodeling of extracellular matrix (ECM) in order to allow endothelial cells to migrate and invade into the surrounding tissue. Matrix metalloproteinases (MMPs) are considered to play a central role in the remodeling of basement membranes and ECM. However, MMPs contribute to vascular remodeling not only by degrading ECM components. Specific MMPs enhance angiogenesis via several ways; they help pericytes to detach from vessels undergoing angiogenesis, release ECM-bound angiogenic growth factors, expose cryptic pro-angiogenic integrin binding sites in the ECM, generate promigratory ECM component fragments, and cleave endothelial cell-cell adhesions. MMPs can also negatively influence the angiogenic process through generating endogenous angiogenesis inhibitors by proteolytic cleavage. Angiostatin, a proteolytic fragment of plasminogen, is one of the most potent antagonists of angiogenesis that inhibits migration and proliferation of endothelial cells. Reports have shown that metalloelastase, pancreas elastase, plasmin reductase, and plasmin convert plasminogen to angiostatin.ResultsWe report here that MMP-19 processes human plasminogen in a characteristic cleavage pattern to generate three angiostatin-like fragments with a molecular weight of 35, 38, and 42 kDa. These fragments released by MMP-19 significantly inhibited the proliferation of HMEC cells by 27% (p = 0.01) and reduced formation of capillary-like structures by 45% (p = 0.05) compared with control cells. As it is known that angiostatin blocks hepatocyte growth factor (HGF)-induced pro-angiogenic signaling in endothelial cells due to structural similarities to HGF, we have analyzed if the plasminogen fragments generated by MMP-19 interfere with this pathway. As it involves the activation of c-met, the receptor of HGF, we could show that MMP-19-dependent processing of plasminogen decreases the phosphorylation of c-met.ConclusionAltogether, MMP-19 exhibits an anti-angiogenic effect on endothelial cells via generation of angiostatin-like fragments.