Immunolocalization of MMP-2 and MMP-9 in human rheumatoid synovium

Matrix metalloproteinase (MMP)-2 and MMP-9, two important members of the matrix metalloproteinase family, have been shown critical contributions in intra-tumor angiogenesis and invasion of tumor progression, and they might also play important roles in the angiogenesis as well as the pannus formation of rheumatoid arthritis (RA). In the present study, we used the immunohistochemistry, the immunofluorescence staining and the con-focal scanning methods to characterize the immunolocalization of MMP-2 and MMP-9 in RA synovium tissues. Our results showed that both MMP-2 and MMP-9 immunostaining could be found in synoviocytes and vascular endothelial cells. Moreover, our con-focal scanning also showed that MMP-2 could be found in infiltrating CD14⁺ monocytes and CD68⁺ macrophages, and MMP-9 could be found in infiltrating CD68⁺ macrophages in RA synovium tissues, while weak or negative staining of these two MMPs could be found in infiltrating CD20⁺B cells and CD3⁺T cells in RA synovium. Thus, our finding suggests that both MMP-2 and MMP-9 expressed by synoviocytes as well as certain infiltrating immune cells role importantly in the angiogenesis in RA progression.     

Tissue factor expression in rheumatoid synovium: a potential role in pannus invasion of rheumatoid arthritis

Angiogenesis, as well as pannus formation within the joint, plays an important role in the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). Tissue factor (TF), an essential initiator of the extrinsic pathway of blood coagulation, is also involved in the angiogenesis and the pannus formation of RA progression. In the present study, we used immunofluorescence and confocal scanning methods to characterize TF immunolocalization in RA synovium. We showed that positive staining of TF could be immunolocalized in synoviocytes, CD19⁺ B cells and CD68⁺ macrophages, whereas weak or negative staining of tissue factor could be found in CD34⁺ endothelial cells of neo-vessels, CD3⁺ T cells and CD14⁺ monocytes in RA synovium tissues. Our study demonstrates a detailed local expression of TF in the rheumatoid synovium, and supports the notion that TF, expressed not only by the synoviocytes themselves, but also the infiltrating CD19⁺ B cells and CD68⁺ macrophages, is involved in the pannus invasion in the progression of rheumatoid arthritis.     

CD147分子通过VEGF促进类风湿关节炎滑膜组织中的血管新生

目的观察类风湿关节炎(RA)滑膜组织中CD147表达强度与血管内皮生长因子(VEGF)表达水平间的相关性,并探讨成纤维样滑膜细胞(FLS)表面CD147的水平变化对VEGF表达的影响。方法收集15例RA患者滑膜,以4例骨关节炎(OA)患者滑膜作对照,采用免疫组织化学SP染色方法检测滑膜组织中CD147和VEGF的表达;体外原代培养FLS细胞,分别加入CD147抗体,PI3K通路阻断剂,MAPK通路的ERK1/2、P38及JNK阻断剂等作用FLS细胞,ELISA检测细胞培养上清中VEGF的表达水平。结果与4例OA滑膜组织CD147和VEGF表达相比,15例RA滑膜组织中均有CD147、VEGF均高表达。其中,表达CD147的细胞主要为成纤维样滑膜细胞、单核-巨噬细胞和淋巴细胞;表达VEGF的细胞主要为成纤维样滑膜细胞、微血管周围成纤维样细胞及血管平滑肌细胞。滑膜组织中CD147和VEGF的表达强度间具有统计学意义。ELISA结果显示,在使用LY294002或抗HAb18GmAb阻断CD147表达后,VEGF的表达量显著下降(P<0.05);而MAPK阻断剂(PD98059、SP600125和SB203580)等对VEGF表达水平无统计学意义(P>0.05)。结论CD147经PI3K-Akt信号通路在RA滑膜组织中上调VEGF促进血管新生。提示CD147在RA血管新生和血管翳形成中有重要意义。     

Expression and tissue localization of membrane-types 1, 2, and 3 matrix metalloproteinases in rheumatoid synovium

In vitro, membrane-type matrix metalloproteinases (MT-MMP) are known to activate the zymogen of MMP-2 (proMMP-2, progelatinase A), which is one of the key MMP in joint destruction in rheumatoid arthritis. In the present study, we examined the production and activation of proMMP-2, and the expression of MT1-MMP, MT2-MMP, and MT3-MMP, their correlation with proMMP-2 activation, and their localization in rheumatoid synovial tissue. Using sandwich enzyme immunoassay and gelatin zymography techniques, proMMP-2 production levels and activation ratios were found to be significantly higher in rheumatoid synovium compared with normal synovium (p < 0.01). Quantitative RT-PCR analyses demonstrated that MT1-MMP and MT3-MMP were expressed in all rheumatoid synovial tissue (30 of 30 cases), but that the mean expression level of MT1-MMP was approximately 11-fold higher than MT3-MMP. Significant correlation was found between the mRNA expression level of MT1-MMP and the activation ratio of proMMP-2 (p < 0.01). In situ hybridization indicated that the hyperplastic lining cells of rheumatoid synovium expressed MT1-MMP. Immunohistochemistry demonstrated that MT1-MMP was co-localized with MMP-2 and with a tissue inhibitor of metalloproteinase-2, and was mainly located in the rheumatoid synovial lining cells. In situ zymography of rheumatoid synovium showed gelatinolytic activity, predominantly in the lining cell layer. This activity was blocked when incubated with BB94, a specific MMP inhibitor. These results demonstrate that MT1-MMP plays an important role in the activation of proMMP-2 in the rheumatoid synovial lining cell layer, and suggest that its activity may be involved in the cartilage destruction of rheumatoid arthritis.     

A preliminary study on the characterization of follicular helper T (Tfh) cells in rheumatoid arthritis synovium

Rheumatoid arthritis (RA) is a chronic and systematic autoimmune inflammatory disease. Recently, a novel T cell subset, follicular helper CD4 T cell (Tfh cells) was found in relation to the pathogenesis and progression of RA, and increased numbers of circulating Tfh cells were found in RA patients. However, there is little evidence regarding the localization of Tfh cells in synovium tissues from RA patients, owing to the lack of an available method to characterize their localization in tissue. The aim of our present study was to characterize the Tfh cells in rheumatoid synovium tissues from RA patients by using immunohistochemistry and triple-fluorescence immunostaining methods. Our results showed that specific staining of CD4, CXCR5 and ICOS could be found on infiltrating immune cells in rheumatoid synovium tissues. The use of triple-fluorescence immunostaining and confocal laser scanning showed immunolocalization of CD4⁺CXCR5⁺ICOS⁺T cells (Tfh cells) in the rheumatoid synovium tissues, whereas these signals were absent in osteoarthritis (OA) synovium and in normal synovium tissues. Thus the data from our present preliminary study support the notion that CD4⁺CXCR5⁺ICOS⁺Tfh cells could be found in rheumatoid synovium tissues from RA patients, indicating the possibility that this T cell subset in synovium tissues may have important roles in the pathogenesis and progression of RA.     

Evaluation of stromal metalloproteinases and vascular endothelial growth factors in a spontaneous metastasis model

This study aims to investigate MMP2 and MT1-MMP protein as well as VEGF-C and VEGF-D mRNA expression in tumor cells and distant organs considered to be targets for metastasis in a tumor spontaneous metastasis model previously described. Cultured tumor cells, able to express pro-MMP2, MMP2, pro-MMP9, and MT1-MMP, develop tumor growth and metastasis, mainly in the liver and spleen, when they are injected in the mammary pad gland of Wistar rats. Immunohistochemical studies of tumor masses showed small groups of tumor cells staining for MT1-MMP but not for MMP2. In the liver, tumor metastatic foci and a stromal positive staining for both MMP2 and MT1-MMP were shown. The spleen and lymph nodes, with only scattered metastatic cells, did not show MMPs immunostaining. Using RT-PCR, a significantly higher VEGF-C and VEGF-D gene expression was shown in the liver of tumor-bearing rats respect to normal rats, whereas spleen and lymph nodes did not show significant differences in mRNA VEGF-C/D levels. Taken together, our results suggest that the stroma microenvironment of target organs for metastasis has the ability to produce MMPs and VEGFs that facilitate the anchorage of tumor cells and promote tumor cell growth and angiogenesis.     

Cytoplasmic tail of MT1-MMP regulates macrophage motility independently from its protease activity

Membrane type-1 matrix metalloproteinase (MT1-MMP) is a proinvasive protease that regulates various cellular functions as evidenced by myriad defects in different types of cells and tissues in MT1-MMP-deficient (MT1^−/–) mice. Here we demonstrate that MT1^−/– mice exhibit fewer infiltrating macrophages into sites of inflammation. MT1^−/–macrophages exhibited a reduced ability to invade reconstituted basement membrane (Matrigel) and invasion by wild type (WT) macrophages was inhibited by a synthetic MMP inhibitor (BB94) to a level similar to that of MT1^−/– cells. The rate of migration of MT1^−/– macrophages was also low compared to that of the WT cells and re-expression of MT1-MMP in MT1^−/– macrophages reconstituted their migratory activity. Unexpectedly, however, BB94 did not inhibit the migration of WT macrophages. The migration-boosting activity of MT1-MMP is retained in a mutant that lacks most of the extracellular portion including the catalytic and hemopexin-like domains. In contrast, deletion of the cytoplasmic (CP) tail abolished the activity completely. Thus, we have demonstrated that MT1-MMP regulates macrophages via its invasion-promoting protease activity as well as its CP-dependent non-proteolytic activity to boost cell migration.     

Fibroblast-like synoviocytes in inflammatory arthritis pathology: the emerging role of cadherin-11

Summary: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease affecting the joint synovium. The normal synovium consists of a lining layer of fibroblast-like synoviocytes (FLS) and macrophages, one to three cells deep that overlies the loose connective tissue of the synovial sublining. During the course of RA, the synovium is the site of inflammation where immune cells are massively infiltrated, and the lining layer becomes hyperplastic and transforms into a pannus tissue that destroys articular cartilage and bone. FLS play an important role in this RA pathogenesis. In this review, we explain that cadherin-11, an adhesion molecule, is selectively expressed on FLS and required for synovial lining formation. In addition, cadherin-11 on FLS contributes to synovial inflammation and mediates cartilage degradation in a mouse model of inflammatory arthritis. Therefore, we suggest that FLS are critical regulators of synovial inflammation and arthritis pathology via mechanisms that are mediated by cadherin-11.     

The role of IL-18 and IL-12 in the modulation of matrix metalloproteinases and their tissue inhibitors in monocytic cells

The matrix metalloproteinases (MMP) are enzymes crucial for the physiological patrol as well as pathological chemotaxis of immune cells to target tissues. The present study examined differential effects of pro-inflammatory [IL-18, IL-12 and tumor necrosis factor (TNF)-alpha] versus anti-inflammatory (IL-4) cytokines on the modulation of MMP and their endogenous tissue inhibitors (TIMP) expression in the U937 cell line. IL-18 and IL-12 separately and synergistically enhanced MMP-2, while TNF-alpha led to the elevation of MMP-9. All pro-inflammatory cytokines enhanced MT1-MMP expression and IL-4 suppressed TNF-alpha-induced MMP-9 expression. This study demonstrated that elevated IL-18 and IL-12, and related pro-inflammatory activity, may be associated with aberrant MMP activity, suggesting modulation of MMP expression using IL-12 and IL-18 antagonists as future therapeutic strategies to attenuate inflammatory and autoimmune disorders.     

Macrophage-derived MT1-MMP and increased MMP-2 activity are associated with glomerular damage in crescentic glomerulonephritis

Membrane-type matrix metalloproteinases (MT-MMPs) have been shown to activate pro-MMP-2 on the cell surface and are suggested to be key enzymes in tissue remodelling under various physiological and pathological conditions. To investigate the role of MT-MMP in progressive renal injury, the gene expression and enzymatic activity of MT-MMP were examined in crescentic glomerulonephritis induced by anti-glomerular basement membrane (GBM) antibody in WKY rats. Isolated glomeruli were subjected to RNA and protein extraction 0, 1, 3, 7, 14, and 28 days after intravenous injection of rabbit anti-GBM antibody. Semiquantitative RT-PCR analysis revealed that among the three members of the MT-MMP family, mRNA expression of MT2-MMP remained unchanged and that of MT3-MMP was not observed in glomeruli during the development of nephritis. However, MT1-MMP gene expression increased from day 3 and reached maximum levels at day 7 (5.5+/-0.7-fold increase over day 0), closely associated with macrophage accumulation, crescent formation, and increased proteinuria. Gelatin zymography showed that the active from of MMP-2 emerged from day 7 and remained during the experimental period accompanied by increased proMMP-2, while no active form of MMP-2 was found in control rats. Using an antisense cRNA probe, intense signals of MT1-MMP mRNA were observed mostly in cells within the crescent and in some cells in the mesangial areas. Most of these cells were ED-1-positive macrophages, based on immunostaining of sequential sections. These results suggested that in the MT-MMP family, MT1-MMP was induced in infiltrating macrophages during the development of crescentic glomerulonephritis and possibly contributed to pathological degradation of glomerular extracellular matrices through the activation of proMMP-2.     

Differential Expression and Origin of Membrane-Type 1 and 2 Matrix Metalloproteinases (MT-MMPs) in Association with MMP2 Activation in Injured Human Livers

Matrix metalloproteinase-2 (MMP2) activation is associated with basement membrane remodeling that occurs in injured tissues and during tumor invasion. The newly described membrane-type MMPs (MT-MMPs) form a family of potential MMP2 activators. We investigated the localization and steady-state levels of MT1-MMP and MT2-MMP mRNA, compared with those of MMP2 and tissue inhibitor of MMP-2 in 22 hepatocellular carcinomas, 12 liver metastases from colonic adenocarcinomas, 13 nontumoral samples from livers with metastases, 10 benign tumors, and 6 normal livers. MMP2 activation was analyzed by zymography in the same series. The expression of MT1-MMP mRNA and the activation of MMP-2 were increased in hepatocellular carcinomas, metastases, and cholestatic nontumoral samples. MT2-MMP mRNA was rather stable in the different groups. MT1-MMP mRNA levels, but not MT2-MMP mRNA, correlated with MMP-2 and tissue inhibitor of MMP-2 mRNA levels and with MMP2 activation. In situ hybridization showed that MT1-MMP mRNA was expressed in stromal cells, and MT2-MMP mRNA was principally located in both hepatocytes and biliary epithelial cells. Consistently, freshly isolated hepatocytes expressed only MT2-MMP mRNA, and culture-activated hepatic stellate cells showed high levels of MT1-MMP mRNA. These results indicate that in injured livers, MMP2 activation is related to a coordinated high expression of MMP2, tissue inhibitor of MMP-2, and MT1-MMP. Furthermore, the finding of a preferential expression of MT2-MMP in hepatocytes, together with our previous demonstration that the activation of stellate cell-derived MMP2 in co-culture requires interactions with hepatocytes (Am J Pathol 1997, 150:51–58), suggests that parenchymal cells might play a pivotal role in the MMP2 activation process.     

(-)Epigallocatechin-3-gallate directly inhibits MT1-MMP activity,leading to accumulation of nonactivated MMP-2 at the cell surface

Consumption of green tea has been associated with prevention of cancer development, metastasis, and angiogenesis. Given the crucial role of the matrix metallo-proteinase-2 (MMP-2) on the degradation of the extracellular matrix instrumental to invasion, we examined the effect of the main flavanol present, (-)epigallocatechin-3-gallate (EGCG), on membrane-type 1 MMP (MT1-MMP), the receptor/activator of MMP-2. In-solution fluorimetric assay with activated MT1-MMP and gelatin-zymography with MT1-MMP catalytic domain alone and pro-MMP-2 activation by the same domain revealed dose-dependent inhibition of MT1-MMP at EGCG concentrations slightly lower than that reported to inhibit MMP-2 and MMP-9. Cytofluorimetry and immunolocalization revealed that EGCG does not impair MT1-MMP/TIMP-2/MMP-2 presence on the cell membrane. In the membrane extract of HT-1080 human fibrosarcoma cells, 10 micro M EGCG caused a strong increase in MT1-MMP level and accumulation of pro-MMP-2 while leaving activated MMP-2 unchanged. EGCG thus exerts inhibition of MT1-MMP, which restrains activation of MMP-2; this may confer the antiangiogenic and antimetastatic activity associated with green tea.     

38Dimerization of endogenous MT1-MMP is a regulatory step in the activation of the 72 kDa gelatinase, MMP-2, on fibroblasts and fibrosarcoma cells

Matrix metalloproteases (MMPs) are centrally engaged in the processes of extracellular matrix turnover that occur during cancer invasion. An important MMP cascade reaction is initiated by the membrane-anchored matrix metalloprotease, MT1-MMP, which serves to activate the proenzyme form of the secreted gelatinase, matrix metalloprotease-2 (MMP-2). This reaction occurs in an interplay with the matrix metalloprotease inhibitor, TIMP-2, and the proposed mechanism involves two molecules of MT1-MMP in complex with one TIMP-2 molecule. To study this, as well as other roles of MT1-MMP, we have now raised a panel of monoclonal antibodies against the protein. These antibodies have been raised in MT1-MMP knock-out mice and react against conserved epitopes in murine and human MT1-MMP. Using one of these antibodies we provide positive evidence that proMMP-2 activation is governed by dimerization of MT1-MMP on the surface of fibroblasts and fibrosarcoma cells. The antibody in question binds specifically to MT1-MMP on the cell surface, as shown by immunofluorescence experiments. It is directed against the hemopexin domain of MT1-MMP and has no effect on the catalytic activity of the protease domain. The antibody induces dimerization of the endogenous MT1-MMP on the cell surface. Through this reaction, it markedly stimulates the formation of the 62 kDa active MMP-2 and the processing into a 59 kDa product that retains gelatinolytic activity. This effect is indeed a consequence of MT1-MMP dimerization because it requires the divalent monoclonal antibody with no effect being obtained with monovalent Fab fragments. Since only a negligible level of proMMP-2 activation is obtained with MT1-MMP expressing cells in the absence of dimerization, our results identify the dimerization event as a critical level of proteolytic cascade regulation.     

Ⅰ型膜型基质金属蛋白酶在癌细胞系中的表达及其与明胶酶A活？…

目的 探讨Ⅰ型膜型基质金属蛋白酶在人肿瘤细胞系中的表达情况及其与明胶酶的分泌和活化的关系。方法 运用逆转录巢式ＰＣＲ,ＲＮＡ印迹分析和蛋白质印迹分析的方法,检测ＭＴ１－ＭＭＰ,ｍＲＮ和ＭＭＰ２蛋白在４个黑色素瘤,２个肺癌和２个前列腺癌细胞系中的表达水平。结果 ＭＴ１－ＭＭＰｍＲＮＡ在所有癌细胞系中均有表达,但表达水平很不一致;在４个黑色素瘤细胞系中的表达水平明显高于肺癌和前列腺癌细胞系;     

Hypoxia promotes murine bone-marrow-derived stromal cell migration and tube formation

Recent evidence indicates that bone-marrow-derived stromal cells (MSCs) have a histology coherent with endothelial cells that may enable them to contribute to tumor angiogenesis through yet undefined mechanisms. In this work, we investigated the angiogenic properties of murine MSCs involved in extracellular matrix degradation and in neovascularization that could take place in a hypoxic environment such as that encountered in tumor masses. MSCs were cultured in normoxia (95% air and 5% CO(2)) or in hypoxia (1% oxygen, 5% CO(2), and 94% nitrogen). We found that hypoxic culture conditions rapidly induced MSC migration and three-dimensional capillary-like structure formation on Matrigel. In vitro, MSC migration was induced by growth-factor- and cytokine-enriched conditioned media isolated from U-87 glioma cells as well as from MSCs cultured in hypoxic conditions, suggesting both paracrine and autocrine regulatory mechanisms. Although greater vascular endothelial growth factor levels were secreted by MSCs in hypoxic conditions, this growth factor alone could not explain their greater migration. Interestingly, matrix metalloproteinase (MMP)-2 mRNA expression and protein secretion were downregulated, while those of membrane-type (MT)1-MMP were strongly induced by hypoxia. Functional inhibition of MT1-MMP by a blocking antibody strongly suppressed MSC ability to migrate and generate capillary-like structures. Collectively, these data suggest that MSCs may have the capacity to participate in tumor angiogenesis through regulation of their angiogenic properties under an atmosphere of low oxygen that closely approximates the tumor microenvironment.     

Role of metalloproteinases MMP-9 and MT1-MMP in CXCL12-promoted myeloma cell invasion across basement membranes

Malignant plasma cells in multiple myeloma home to the bone marrow (BM), accumulate in different niches and, in late disease, migrate from the BM into blood. These migratory events involve cell trafficking across extracellular matrix (ECM)-rich basement membranes and interstitial tissues. Metalloproteinases (MMP) degrade ECM and facilitate tumour cell invasion. The chemokine CXCL12 is expressed in the BM, and it was previously shown that it triggers myeloma cell migration and activation. In the present work we show that CXCL12 promotes myeloma cell invasion across Matrigel-reconstituted basement membranes and type I collagen gels. MMP-9 activity was required for invasion through Matrigel towards CXCL12, whereas TIMP-1, a MMP-9 inhibitor that we found to be expressed by myeloma and BM stromal cells, impaired the invasion. In addition, we show that the membrane-bound MT1-MMP metalloproteinase is expressed by myeloma cells and contributes to CXCL12-promoted myeloma cell invasion across Matrigel. Increase in MT1-MMP expression, as well as induction of its membrane polarization by CXCL12 in myeloma cells, might represent potential mechanisms contributing to this invasion. CXCL12-promoted invasion across type I collagen involved metalloproteinases different from MT1-MMP. These data indicate that CXCL12 could contribute to myeloma cell trafficking in the BM involving MMP-9 and MT1-MMP activities.