HIROYUKI Nakamura DDS PhD

Abstract: Matrix metalloproteinases (MMPs) are involved in extracellular matrix degradation and the modulation of cell behavior. These proteinases have also been implicated in tissue repair and regeneration. Our previous studies have demonstrated that MMP-3 elicits stimulatory effects on the proliferation and the migration of endothelial cells as well as anti-apoptotic effects on these cells in vitro. In addition, we found that MMP-3 enhanced the regeneration of lost pulp tissue in a rat incisor pulp injury model. However, continuously erupting rodent incisors exhibit significantly different pulp organization compared with mature erupted teeth. Therefore, we have further extended these studies using a canine irreversible pulpitis model to investigate the effects of MMP-3. In this study, the crowns of the canine mature premolars were removed and the pulp tissues were amputated. The amputated pulp tissues remained exposed for 24 or 72 hours to induce mild or severe irreversible pulpitis, respectively, followed by sealing of the cavities. In both models, the whole pulp tissues became necrotic by day 14. In this mild pulpitis model, the regeneration of pulp tissue with vasculature and nerves was observed until 14 days after sealing with MMP-3, followed by extracellular matrix formation in the regenerated pulp tissues until day 28. The treatment with MMP-3 resulted in a decrease in the number of macrophage and antigen-presenting cells and a significant inhibition of IL-6 expression on day 3. The inhibition of MMP-3 activity abolished these anti-inflammatory effects. Immunofluorescence staining demonstrated that MMP-3 was involved in the modification of serum-derived hyaluronan-associated proteins and hyaluronan (SHAP-HA) complexes possibly through the degradation of versican. These results demonstrate that MMP-3 can act as an anti-inflammatory agent and suggest that MMP-3 might represent a useful therapy for the treatment of mild irreversible pulpitis.

Abstract: Fetal cells enter the maternal circulation from the early first trimester of pregnancy, where they persist in tissue decades later. We investigated in mice whether fetal microchimeric cells (FMCs) can be detected in maternal kidney, and whether they play a role in kidney homeostasis. FMCs were identified in vivo in two models: one an adaptive model following unilateral nephrectomy, the other an injury via unilateral renal ischaemia reperfusion. Both models were carried out in mothers that had been mated with transgenic mice expressing luciferase transgene under the control of collagen type I, and had given birth to either 1 or 3 litters. FMCs were detected by Y-probe fluorescent in situ hybridization (FISH) and bioluminescence, and the cell number quantified by real-time polymerase chain reaction. In the adaptive model, the remaining kidney showed more cells by all 3 parameters compared with the nephrectomized kidney, while ischaemia reperfusion resulted in higher levels of FMC participation in injured compared to contralateral kidneys. Bioluminescence showed that FMCs switch on collagen type I transcription implicating mesenchymal lineage cells. After injury, Y-probe in situ hydridization was found mainly in the tubular epithelial network. Finally, we compared FMCs with bone marrow cells and found similar dynamics but altered distribution within the kidney. We conclude that FMCs (1) are long-term sequelae of pregnancy and (2) are recruited to the kidney as a result of injury or adaptation, where they activate the transcriptional machinery of matrix proteins.

Abstract: OBJECTIVE: Connective tissue growth factor (CTGF) is a cysteine-rich secreted matricellular protein involved in wound healing and tissue repair. Enhanced and prolonged expression of CTGF has been associated with tissue fibrosis in humans. However, questions remain as to whether CTGF expression alone is sufficient to drive fibrosis. This study was undertaken to investigate whether CTGF alone is sufficient to cause fibrosis in intact animals and whether its effects are mediated through activation of transforming growth factor beta (TGFbeta) signaling or through distinct signal transduction pathways. METHODS: We generated mice overexpressing CTGF in fibroblasts under the control of the fibroblast-specific collagen alpha2(I) promoter enhancer. Tissues such as skin, lung, and kidney were harvested for histologic analysis. Mouse embryonic fibroblasts were prepared from embryos (14.5 days postcoitum) for biochemical analysis. RESULTS: Mice overexpressing CTGF in fibroblasts were susceptible to accelerated tissue fibrosis affecting the skin, lung, kidney, and vasculature, most notably the small arteries. We identified a marked expansion of the myofibroblast cell population in the dermis. RNA analysis of transgenic dermal fibroblasts revealed elevated expression of key matrix genes, consistent with a fibrogenic response. CTGF induced phosphorylation of p38, ERK-1/2, JNK, and Akt, but not Smad3, in transgenic mouse fibroblasts compared with wild-type mouse fibroblasts. Transfection experiments showed significantly increased basal activity of the CTGF and serum response element promoters, and enhanced induction of the CTGF promoter in the presence of TGFbeta. CONCLUSION: These results demonstrate that selective expression of CTGF in fibroblasts alone causes tissue fibrosis in vivo through specific signaling pathways, integrating cues from the extracellular matrix into signal transduction pathways to orchestrate pivotal biologic responses relevant to tissue repair and fibrosis.

Abstract: We investigated whether the affinity of tissue inhibitor of metalloproteinases (TIMP)-3 for adamalysins with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5 is affected by the non-catalytic ancillary domains of the enzymes. For this purpose, we first established a novel method of purifying recombinant FLAG-tagged TIMP-3 and its inhibitory N-terminal domain (N-TIMP-3) by treating transfected HEK293 cells with sodium chlorate to prevent heparan sulfate proteoglycan-mediated TIMP-3 internalization. TIMP-3 and N-TIMP-3 affinity for selected matrix metalloproteinases and forms of ADAMTS-4 and -5 lacking sequential C-terminal domains was determined. TIMP-3 and N-TIMP-3 displayed similar affinity for various matrix metalloproteinases as has been previously reported for E. coli-expressed N-TIMP-3. ADAMTS-4 and -5 were inhibited more strongly by N-TIMP-3 than by full-length TIMP-3. The C-terminal domains of the enzymes enhanced interaction with N-TIMP-3 and to a lesser extent with the full-length inhibitor. For example, N-TIMP-3 had 7.5-fold better K(i) value for full-length ADAMTS-5 than for the catalytic and disintegrin domain alone. We propose that the C-terminal domains of the enzymes affect the structure around the active site, favouring interaction with TIMP-3.

Abstract: ADAMTS-4 (aggrecanase-1) and ADAMTS-5 (aggrecanase-2) are multidomain metalloproteinases belonging to the ADAMTS family. We have previously reported that human ADAMTS-5 has much higher aggrecanolytic activity than human ADAMTS-4. To investigate the different proteolytic activity of the two enzymes, we generated a series of chimeras by exchanging various non-catalytic domains of the two proteinases. We found that the catalytic domain of ADAMTS-5 has higher intrinsic catalytic ability than that of ADAMTS-4. The studies also demonstrated that the non-catalytic domains of ADAMTS-5 are more effective modifiers than those of ADAMTS-4, making both catalytic domains more active against aggrecan, an Escherichia coli-expressed interglobular domain of aggrecan and fibromodulin. Addition of the C-terminal thrombospondin type I motif of ADAMTS-5 to the C terminus of ADAMTS-4 increased the activity of ADAMTS-4 against aggrecan and fibromodulin severalfold. In contrast to previous reports (Kashiwagi, M., Enghild, J. J., Gendron, C., Hughes, C., Caterson, B., Itoh, Y., and Nagase, H. (2004) J. Biol. Chem. 279, 10109-10119 and Gao, G., Plaas, A., Thompson, V. P., Jin, S., Zuo, F., and Sandy, J. D. (2004) J. Biol. Chem. 279, 10042-10051), our detailed investigation of the role of the C-terminal spacer domain of ADAMTS-4 indicated that full-length ADAMTS-4 is approximately 20-times more active against aggrecan than its spacer domain deletion mutant, even at the Glu373-Ala374 site of the interglobular domain. This discrepancy is most likely due to selective inhibition of full-length ADAMTS-4 by heparin, particularly for cleavage at the Glu373-Ala374 bond. However, removal of the spacer domain from ADAMTS-4 greatly enhanced more general proteolytic activity against non-aggrecan substrates, e.g. E. coli-expressed interglobular domain, fibromodulin, and carboxymethylated transferrin.

Abstract: OBJECTIVE: To investigate whether matrix metalloproteinases (MMPs) and/or aggrecanase in synovial fluid can be used as biochemical markers in the diagnosis of internal derangement (ID) of the temporomandibular joint (TMJ). STUDY DESIGN: Forty-four samples of synovial fluid were obtained from 35 patients with ID and osteoarthritis (OA) and 15 normal samples from 10 asymptomatic volunteers. MMP-2, -9, and aggrecanase in the synovial fluid were examined by immunoblotting. RESULTS: The incidences of MMP-2, -9, and aggrecanase expression in the ID and OA group were significantly higher than those in the normal group (P < .05). Those with anterior disc displacement without reduction and severe OA showed significantly high expression of MMP-9 compared with other disease subgroups (P < .05). Conversely, comparatively high expression of MMP-2 and aggrecanase was shown in the early-stage OA group. However, there was no significant difference in expression of MMP-2 and aggrecanase among disease subgroups. CONCLUSIONS: These findings suggested that expression of aggrecanase could be a potential biochemical marker for articular cartilage degradation in ID of the TMJ.

Abstract: OBJECTIVES: To determine whether or not aggrecanase in synovial fluid can be used as a biochemical marker in the diagnosis of temporomandibular joint disorder (TMJD). MATERIALS AND METHODS: Forty-four samples of synovial fluid were obtained from 35 patients with internal derangement or osteoarthritis and 15 control samples from 10 asymptomatic volunteers. Aggrecanase in the synovial fluid was examined by immunoblotting. RESULT: The incidence of aggrecanase expression in TMJD group were significantly higher than that in the normal control group (P < 0.05). Those with severe OA and anterior disc displacement without reduction showed significantly high expression of aggrecanase compared with other disease subgroups (P < 0.05). CONCLUSION: These findings suggested that aggrecanase could be a potential biochemical marker for cartilage degeneration in the TMJD.

Abstract: Gastric carcinomas can be classified into scirrhous carcinomas (SC), i.e. 'linitis plastica' or Borrmann 4 gastric cancer, and non-scirrhous carcinomas (NSC). SC are characterized by diffuse invasive growth patterns with marked fibrosis, frequent peritoneal dissemination and lymph-node metastases and poor prognosis, while NSC show medullary growth patterns and common hematogenous metastases. To study the differences in local expression levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) between SC and NSC, we examined the expression of MMPs and TIMPs in human gastric carcinoma tissues by several methods including sandwich-enzyme immunoassay systems, gelatin zymography, reverse transcriptase-polymerase chain reaction (RT-PCR), real-time quantitative PCR, immunoblotting, immunohistochemistry and in situ zymography. Of the seven MMPs and two TIMPs tested, only proMMP-2 levels were remarkably higher in SC than in NSC (P < 0.01), and proMMP-2 activation ratio was significantly lower in SC than in NSC (P < 0.05). TIMP-3 mRNA levels were remarkably about 2-fold higher in SC than in NSC tissues (P < 0.01). TIMP-3 production in SC was confirmed by immunoblotting and TIMP-3 was immunolocalized to stromal fibroblasts in SC. TIMP-3 mRNA levels inversely correlated with proMMP-2 activation ratios, although the expression levels of MT1-MMP and MT2-MMP were not different in SC and NSC. By in situ zymography, gelatinolytic activity appeared to be weaker in SC than in NSC. All these data suggest that proMMP-2 activation is down-regulated by TIMP-3 expressed in scirrhous gastric carcinomas. Our findings may explain the differences in clinical behaviors of SC and NSC.

Abstract: CD44 is a receptor for hyaluronan and mediates signaling that regulates complex cell behavior including cancer cell migration and invasion. Shedding of the extracellular portion of CD44 is the last step in the regulation of the molecule-releasing interaction between the ligand and cell. However, highly glycosylated forms of CD44 have hampered the identification of the exact cleavage sites for shedding and the responsible proteases. In this study, we found that expression of membrane-type 1 matrix metalloproteinase (MT1-MMP) increased shedding of the 65-70 kDa CD44H (standard form) fragments and generated two additional smaller fragments. We purified the shed fragments and identified the cleaved sites by mass spectrometry. Specific antibodies that recognize the newly exposed COOH terminus by cleavage were prepared and used to analyze shedding at each site. Shedding of the 65-70 kDa fragments was inhibited by tissue inhibitor of metalloproteinase 3 (TIMP-3) but not by TIMP-1 and TIMP-2, suggesting involvement of a disintegrin and metalloproteinase (ADAM)-like proteases, although shedding is affected by MT1-MMP. Conversely, shedding of the two smaller fragments was inhibited by TIMP-2 and TIMP-3 but not TIMP-1, suggesting involvement of MT1-MMP itself. Shed fragments cleaved at these sites were also detected in human tumor tissues. Increased shedding at one of the MT1-MMP-sensitive sites was observed in the tumor compared with the surrounding normal tissue. However, no significant difference was observed with shedding by ADAM-like proteases. Thus, the cleavage sites for the shedding of CD44H were identified for the first time, and the results provide a basis for exploring the unknown biologic roles of shedding at different sites.

Abstract: CD44 is an enigmatic cell adhesion molecule acting as a major receptor for hyaluronan and playing roles in many biological and pathological processes such as lymphocyte homing, T-cell activation, wound healing, angiogenesis, and metastatic spread of tumor cells. However, the complexity of the molecule, with its alternatively spliced variants, extensive glycosylation, and processing by different proteases, has hampered detailed analysis. In this study, we prepared four monoclonal antibodies (285-2F12, 284-43F1, 268-1F5, and 294-6F2) and one polyclonal antibody (C6) that recognize defined sequences in the stem region of CD44H. Interestingly, two of the monoclonal antibodies, 268-1F5 and 294-6F2, failed to recognize the CD44 expressed in five of the seven human tumor cell lines examined by Western blotting. Treatment of the samples with a combination of neuraminidase and O-glycosidase as well as the expression of mutants with site-directed mutations at possible modification sites rendered the CD44 reactive to the antibodies. Thus, the reactivity of the antibodies is sensitive to O-glycosylation presumably near the recognition sites. Glycosylation of CD44 that affects reactivity to the antibodies was found to be regulated differentially between tumor and stromal cells in two breast and three oral carcinoma tissues. Antibody 268-1F5 reacted to the tumor cells, but not to the cells in the surrounding stroma. On the other hand, the reactivity of 294-6F2 to the cells was opposite between the two tumor types. Thus, these sets of antibodies are useful to detect and analyze the as-yet-unknown roles of site-specific glycosylation of CD44, particularly in tumors.

Abstract: Vascular endothelial growth factor (VEGF) is a strong angiogenic mitogen and plays important roles in angiogenesis under various pathophysiological conditions. The in vivo angiogenic activity of secreted VEGF may be regulated by extracellular inhibitors, because it is also produced in avascular tissues such as the cartilage. To seek the binding inhibitors against VEGF, we screened the chondrocyte cDNA library by a yeast two-hybrid system by using VEGF165 as bait and identified connective tissue growth factor (CTGF) as a candidate. The complex formation of VEGF165 with CTGF was first established by immunoprecipitation from the cells overexpressing both binding partners. A competitive affinity-binding assay also demonstrated that CTGF binds specifically to VEGF165 with two classes of binding sites (Kd = 26 +/- 11 nM and 125 +/- 38 nM). Binding assay using deletion mutants of CTGF indicated that the thrombospondin type-1 repeat (TSP-1) domain of CTGF binds to the exon 7-coded region of VEGF165 and that the COOH-terminal domain preserves the affinity to both VEGF165 and VEGF121. The interaction of VEGF165 with CTGF inhibited the binding of VEGF165 to the endothelial cells and the immobilized KDR/IgG Fc; that is, a recombinant protein for VEGF165 receptor. By in vitro tube formation assay of endothelial cells, full-length CTGF and the deletion mutant possessing the TSP-1 domain inhibited VEGF165-induced angiogenesis significantly in the complex form. This antiangiogenic activity of CTGF was demonstrated further by in vivo angiogenesis assay by using Matrigel injection model in mice. These data demonstrate for the first time that VEGF165 binds to CTGF through a protein-to-protein interaction and suggest that the angiogenic activity of VEGF165 is regulated negatively by CTGF in the extracellular environment.

Abstract: ADAMTS4 (aggrecanase-1) is considered to play a key role in the degradation of aggrecan in arthritides. The inhibitory activity of tissue inhibitors of metalloproteinases (TIMPs) to ADAMTS4 was examined in an assay using aggrecan substrate. Among the four TIMPs, TIMP-3 inhibited the activity most efficiently with an IC(50) value of 7.9 nM, which was at least 44-fold lower than that of TIMP-1 (350 nM) and TIMP-2 (420 nM) and >250-fold less than that of TIMP-4 (2 microM for 35% inhibition). These results suggest that TIMP-3 is a potent inhibitor against the aggrecanase activity of ADAMTS4 in vivo.

Abstract: 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.

Abstract: We measured the production levels of seven different matrix metalloproteinases (MMP-1, 2, 3, 7, 8, 9 and 13) and two tissue inhibitors of metalloproteinases (TIMP-1 and 2) in the homogenates of human oral squamous cell carcinomas and control normal squamous epithelia by the corresponding sandwich enzyme immunoassay systems. The levels of MMP-1, 2, 3, 8, 9, 13 and TIMP-1 were significantly higher in the carcinoma samples than in the control. Among them, only the production level of MMP-2 was significantly higher in the carcinomas with cervical lymph node metastasis than in those without metastasis (P < 0.05). Gelatin zymography demonstrated that activation ratio of the zymogen of MMP-2 (proMMP-2) is significantly higher in the carcinomas with lymph node metastasis than in those without metastasis (P < 0.05) or normal control (P < 0.01). Quantitative RT-PCR for membrane-types 1, 2 and 3 MMPs (MT1, 2 and 3-MMPs), which activate proMMP-2 in vitro, demonstrated that MT1-MMP is predominantly expressed in the carcinoma tissues, and the expression level is significantly higher in the carcinomas with lymph node metastasis than in those without metastasis (P < 0.05) or the control samples (P < 0.05). Although MT2-MMP and MT3-MMP were detected in approximately 30% of the carcinoma cases, their expression levels were extremely lower compared with that of MT1-MMP. There was a direct correlation between the MT1-MMP expression level and proMMP-2 activation ratio (r = 0.62, P < 0.01). In situ hybridization and immunohistochemistry indicated that carcinoma cells and stromal cells adjacent to carcinoma cell nests express MT1-MMP transcripts and protein. MMP-2 and TIMP-2 were also immunolocalized to the carcinoma cells in the carcinoma samples. By in situ zymography, gelatinolytic activity was demonstrated in the carcinoma cell nests and abolished by the treatment with an MMP inhibitor, BB94. These results suggest that among seven different MMPs, the production of proMMP-2 and its activation mediated by MT1-MMP play an important role in the cervical lymph node metastasis of the human oral squamous cell carcinomas.

Abstract: OBJECTIVE: Matrix metalloproteinases (MMPs) are expressed in joint tissues of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). The objective of this study was to define the steady state levels of seven different MMPs and two tissue inhibitors of metalloproteinases (TIMPs) as well as the potential metalloproteinase activity in the synovial fluid (SF) to provide more insight into the role of MMPs in cartilage destruction in RA and OA. METHODS: Levels of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-13, TIMP-1, and TIMP-2 in SF aspirated from knee joints of 97 patients with RA and 103 patients with OA were measured by the corresponding one step sandwich enzyme immunoassays. Proteolytic activity of MMPs in these SFs was examined in an assay using [(3)H]carboxymethylated transferrin substrate in the presence of inhibitors of serine and cysteine proteinases after activation with p-aminophenylmercuric acetate (APMA). Destruction of RA knee joints was radiographically evaluated. RESULTS: Levels of MMP-1, MMP-2, MMP-3, MMP-8, and MMP-9 were significantly higher in RA SF than in OA SF. MMP-7 and MMP-13 were detectable in more than 45% of RA SFs and in less than 20% of OA SFs, respectively. Among the MMPs examined, MMP-3 levels were extremely high compared with those of other MMPs. Direct correlations were seen between the levels of MMP-1 and MMP-3 and between those of MMP-8 and MMP-9 in RA SF. Although the levels of MMP-1 and MMP-3 increased even in the early stage of RA, those of MMP-8 and MMP-9 were low in the early stage and increased with the progression of RA. Molar ratios of the total amounts of the MMPs to those of the TIMPs were 5.2-fold higher in patients with RA than in OA, which was significant. APMA-activated metalloproteinase activity in SF showed a similar result, and a direct correlation was seen between the molar ratios and the activity in RA SF. CONCLUSIONS: Our results show that high levels of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, and TIMP-1 are present in RA SF and suggest that once these MMPs are fully activated, they have an imbalance against TIMPs, which may contribute to the cartilage destruction in RA.

Abstract: A disintegrin-like and metalloproteinase with thrombospondin type I motifs-1 (ADAMTS-1) is an extracellular matrix-anchored metalloproteinase. In this study we have demonstrated that ADAMTS-1 is able to cleave a major cartilage proteoglycan, aggrecan. N-terminal sequencing analysis of the cleavage product revealed that ADAMTS-1 cleaves the Glu(1871)-Leu(1872) bond within the chondroitin sulfate attachment domain of aggrecan. In addition, deletional analysis demonstrated that the C-terminal spacer region of ADAMTS-1 is necessary to degrade aggrecan. These results suggest that ADAMTS-1 may be involved in the turnover of aggrecan in vivo.

Abstract: Brevican is a member of the lectican family of chondroitin sulfate proteoglycans that is predominantly expressed in the central nervous system. The susceptibility of brevican to digestion by matrix metalloproteinases (MMP-1, -2, -3, -7, -8, -9, -10, and -13 and membrane type 1 and 3 MMPs) and aggrecanase-1 (ADAMTS4) was examined. MMP-1, -2, -3, -7, -8, -10, and -13 degraded brevican into a few fragments with similar molecular masses, whereas the degradation products of aggrecanase-1 had apparently different sizes. NH(2)-terminal sequence analyses of the digestion fragments revealed that cleavages of the brevican core protein by these metalloproteinases occurred commonly within the central non-homologous domain. MMP-1, -2, -3, -7, -8, -10, and -13 preferentially attacked the Ala(360)-Phe(361) bond, whereas aggrecanase-1 cleaved the Glu(395)-Ser(396) bond, which are similar to the cleavage sites observed with cartilage proteoglycan (aggrecan) for the MMPs and aggrecanase-1, respectively. These data demonstrate that MMP-1, -2, -3, -7, -8, -10, and -13 and aggrecanase-1 digest brevican in a similar pattern to aggrecan and suggest that they may be responsible for the physiological turnover and pathological degradation of brevican.

Abstract: OBJECTIVE: To determine the effects of calcium pentosan polysulfate (CaPPS) on the production of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMP), in cultures of rheumatoid synovial fibroblasts. METHODS: The production of MMP-1, -2, -3, -7, -8, -9, and -13 and of TIMP-1, -2, -3, and -4 in cultured rheumatoid synovial fibroblasts treated with 0.1, 1, and 10 microg/ml CaPPS in the presence and absence of 100 units/ml interleukin-1alpha (IL-1alpha) was examined by a sandwich enzyme immunoassay system and/or immunoblotting. The messenger RNA (mRNA) expression of TIMP-3 and membrane type 1 MMP was determined by Northern blotting, and the cells expressing TIMP-3 gene in rheumatoid synovium were identified by in situ hybridization. The synthesis and secretion of TIMP-3 protein were monitored by pulse-chase experiments. TIMP-3 was immunolocalized in untreated or CaPPS-treated rheumatoid synovial fibroblasts and synovium using an avidin-biotin-peroxidase complex method. RESULTS: Treatment of cultured rheumatoid synovial fibroblasts with CaPPS resulted in a dose-dependent increase in the production of TIMP-3 in both cell lysates and media from the treated cells. However, CaPPS did not affect the levels of the other MMPs or TIMPs examined. The production of TIMP-3 was further enhanced in the cells treated with both IL-1alpha and CaPPS. Immunohistochemistry confirmed the enhanced production of TIMP-3 by cells exposed to CaPPS. The mRNA level of TIMP-3 increased 3.4-fold by treating rheumatoid synovial fibroblasts with IL-1alpha, but CaPPS itself did not alter the expression levels in the IL-1alpha-treated or -untreated cells. Pulse-chase studies demonstrated that translation for TIMP-3 protein was enhanced by CaPPS treatment. In situ hybridization and immunohistochemistry indicated that TIMP-3 was expressed mainly in the hyperplastic lining cells of rheumatoid synovium, and that the production of this protein by these immunoreactive lining cells was significantly increased by treatment with CaPPS. CONCLUSION: The present study is the first to demonstrate that the new antiarthritic drug, CaPPS, selectively enhanced TIMP-3 production at the posttranscription level in cultured rheumatoid synovial fibroblasts and in the lining cells of rheumatoid synovium. By this mechanism, CaPPS may be able to modulate joint tissue destruction in rheumatoid arthritis.

Abstract: Membrane type 3 matrix metalloproteinase (MT3-MMP), an activator for the zymogen of MMP-2 (proMMP-2, or progelatinase A), is known to be expressed in human placenta, brain, lung and rat vascular smooth muscle cells, but information about its biochemical properties is limited. In the present study, we expressed and purified a truncated form of MT3-MMP lacking the transmembrane and intracytoplasmic domain (DeltaMT3) and characterized the enzyme biochemically. DeltaMT3 digested type III collagen into characteristic 3/4- and 1/4-fragments by cleaving the Gly781-Ile782 and Gly784-Ile785 bonds of alpha1(III) chains. Although DeltaMT3 did not have such an activity against type I collagen, it attacked the Gly4-Ile5 bond of the triple helical portion of alpha2(I) chains, leading to removal of the crosslink containing N-terminal telopeptides. By quantitative analyses of the activities of DeltaMT3 and a similar deletion mutant of MT1-MMP (DeltaMT1), DeltaMT3 was approximately fivefold more efficient at cleaving type III collagen. DeltaMT3 also digested cartilage proteoglycan, gelatin, fibronectin, vitronectin, laminin-1, alpha1-proteinase inhibitor and alpha2-macroglobulin into almost identical fragments to those given by DeltaMT1, although carboxymethylated transferrin digestion by DeltaMT3 generated some extra fragments. The activity of DeltaMT3 was inhibited by tissue inhibitor of metalloproteinases-2 (TIMP-2) and TIMP-3 in a 1 : 1 stoichiometry, but not by TIMP-1. ProMMP-2 was partially activated by DeltaMT3 to give the intermediate form. These results indicate that, like MT1-MMP, MT3-MMP exhibits proteolytic activities against a wide range of extracellular matrix molecules. However, differences in the proMMP-2 activation and tissue distribution suggest that MT3-MMP and MT1-MMP play different roles in the pathophysiological digestion of extracellular matrix.

Abstract: Three different membrane-type matrix metalloproteinases (MT1-, MT2-, and MT3-MMPs) are known to activate in vitro the zymogen of MMP-2 (pro-MMP-2, progelatinase A), which is one of the key MMPs in invasion and metastasis of various cancers. In the present study, we have examined production and activation of pro-MMP-2, expression of MT1-, MT2-, and MT3-MMPs and their correlation with pro-MMP-2 activation, and localization of MMP-2, MT1-MMP, and MT2-MMP in human astrocytic tumors. The sandwich enzyme immunoassay demonstrates that the production levels of pro-MMP-2 in the anaplastic astrocytomas and glioblastomas are significantly higher than that in the low-grade astrocytomas (P<0.05 and P<0.01, respectively), metastatic brain tumors (P<0.05), or normal brains (P<0.01). Gelatin zymography indicates that the pro-MMP-2 activation ratio is significantly higher in the glioblastomas than in other astrocytic tumors (P<0.01), metastatic brain tumors (P<0.01), and normal brains (P<0.01). The quantitative reverse transcription polymerase chain reaction analyses demonstrate that MT1-MMP and MT2-MMP are expressed predominantly in glioblastoma tissues (17/17 and 12/17 cases, respectively), and their expression levels increase significantly as tumor grade increases. MT3-MMP is detectable in both astrocytic tumor and normal brain tissues, but the mean expression level is approximately 50-fold lower compared with that of MT1-MMP and MT2-MMP in the glioblastomas. The activation ratio of pro-MMP-2 correlates directly with the expression levels of MT1-MMP and MT2-MMP but not MT3-MMP. In situ hybridization indicates that neoplastic astrocytes express MT1-MMP and MT2-MMP in the glioblastoma tissues (5/5 cases and 5/5 cases, respectively). Immunohistochemically, MT1-MMP and MT2-MMP are localized to the neoplastic astrocytes in glioblastoma samples (17/17 cases and 12/17 cases, respectively), which are also positive for MMP-2. In situ zymography shows gelatinolytic activity in the glioblastoma tissues but not in the normal brain tissues. These results suggest that both MT1-MMP and MT2-MMP play a key role in the activation of pro-MMP-2 in the human malignant astrocytic tumors and that the gelatinolytic activity is involved in the astrocytic tumor invasion.

Abstract: Matrix metalloproteinases (MMPs) are believed to be involved in the invasion and metastasis of various human carcinomas. In the present study, the production levels of seven different MMPs (MMP-1, -2, -3, -7, -8, -9, and -13), the activation of the zymogen of MMP-2 (proMMP-2), the expression of membrane-type MMPs (MT1-, MT2-, and MT3-MMPs), and the tissue localization of the activated enzyme were examined in human invasive papillary thyroid carcinomas. Sandwich enzyme immunoassays revealed that among the MMPs examined, only the MMP-2 production level is significantly enhanced in the carcinoma tissues compared with the follicular adenoma and normal control thyroid tissues. Gelatin zymography indicated that the proMMP-2 activation ratio is considerably higher in carcinomas with lymph node metastasis than it is in those without metastasis, follicular adenomas, or normal controls (P < 0.01). Northern blot analysis of the expression of MT1-, MT2-, and MT3-MMPs, which are known to activate proMMP-2 in vitro, demonstrated the predominant expression of MT1-MMP mRNA in the carcinoma tissues (15 of 15 cases), whereas MT2-MMP expression was confined to 26% of the cases (4 of 15 cases), and no consistent expression of MT3-MMP was observed. MTI-MMP mRNA expression levels correlated with the proMMP-2 activation ratio (r = 0.692; P < 0.01), but such a correlation was not obtained with MT2-MMP. There was also a direct correlation between MT1-MMP expression and lymph node metastasis (P < 0.05). In situ hybridization indicated that both carcinoma and stromal cells express MT1-MMP transcripts (five of six cases). MT1-MMP was also immunolocalized to carcinoma and stromal cells in all of the carcinoma samples (26 of 26 cases), which were positive for MMP-2. In situ zymography indicated definite gelatinolytic activity in the carcinoma cell nests, which was abolished by incubation of the carcinoma samples with a synthetic MMP inhibitor before the reaction. These results suggest for the first time that among seven different MMPs, the production of proMMP-2 and its MT1-MMP-mediated activation in the carcinoma cell nests play an important role in the lymph node metastasis of human invasive papillary thyroid carcinomas.

Abstract: Matrix metalloproteinases (MMP) are synthesized as inactive zymogens (proMMP) and subsequently activated by many factors to degrade the extracellular matrix (ECM). In the present study, we have examined the intermolecular activation mechanisms of proMMP by MMP-10 (stromelysin 2). ProMMP-10 was purified from the culture media of OSC-20 human oral squamous carcinoma cells stimulated with 12-O-tetradecanoylphorbol 13-acetate. The final products are partially activated (approximately 38% of the full activity) during the purification steps and contain proMMP-10 of Mr 56,000 with minor protein bands of Mr 47,000, 24,000 and 22,000. The zymogen is activated by 4-aminophenylmercuric acetate and processed to the active forms of Mr 47,000 and 24,000. The NH2-terminal sequence of the 47,000- and 24,000-Mr species is Phe82-Ser-Ser-Phe-Pro-Gly, which is identical to that of stromelysin 2. ProMMP-9 (progelatinase B) is activated by MMP-10 to its full activity and processed to the low-Mr species of Mr 81,000, 65,000, 57,000 and 55,000, the former two of which show proteolytic activity on a gelatin zymography. The NH2-terminal sequence analysis indicates that the 81,000-, 65,000- and 57,000-M, species have the identical sequence of Phe88-Gln-Thr-Phe-Glu-Gly, suggesting the cleavage of the Arg87-Phe88 peptide bond for activation and both NH2-terminal and COOH-terminal truncation in the 65,000- and 57,000-Mr forms. MMP-10 also activates proMMP-7 (promatrilysin) up to about 60% of the full activity and generates the same active species of Mr 19,000 as that obtained by activation with 4-aminophenylmercuric acetate. Incubation of proMMP-2 (progelatinase A) or proMMP-3 with MMP-10 does not result in activation of these proMMP. These results indicate that in addition to the previously reported activation of proMMP-1 (tissue procollagenase) and proMMP-8 (neutrophil procollagenase), MMP-10 can also activate proMMP-9 and proMMP-7, and suggest the possibility that MMP-10 may replace a role of MMP-3 in the ECM degradation in concert with other MMP under various pathological conditions.

Abstract: Activation of the zymogen of matrix metalloproteinase 2 (proMMP-2, progelatinase A) possibly is one of the key steps in invasion and metastasis of various human carcinomas. Three different membrane-type MMPs (MT-MMPs), MT1-, MT2-, and MT3-MMPs are thought to be activators of proMMP-2 in the tissues. MT4-MMP is structurally different from the other three enzymes, and its function as proMMP-2 activator is uncertain. In the present study of human invasive breast carcinomas, we examined a correlation between the expression of MT1-, MT2-, and MT3-MMPs, immunolocalization of MT1- and MT2-MMPs, and proMMP-2 activation. Northern blot analysis demonstrated the predominant expression of MT1-MMP mRNA in carcinoma tissues (20 of 20 cases), whereas MT2-MMP was detected in only 25% of the cases (5 of 20 cases), and no detectable expression of MT3-MMP was observed. The expression levels of MT1-MMP but not MT2-MMP correlated well with the presence of lymph node and distant metastases, clinical stages, and size of tumors. Immunohistochemically, MT1-MMP was localized predominantly in the carcinoma cells in all of the samples (32 of 32 cases). Immunostaining of MT2-MMP in the carcinoma cells was observed in only 38% of the cases (12 of 32 cases). Immunoblot analysis of tumor homogenates confirmed the presence of these MT-MMPs. Activation of proMMP-2 was significantly higher in the carcinoma samples with lymph node or distant metastasis compared to carcinoma without metastasis, normal control, or fibrocystic disease (P < 0.05). An increase in the activation ratio of proMMP-2 correlated directly with the expression of MT1-MMP but not MT2-MMP, as measured by either Northern blot analysis or immunostaining. These results suggest that MT1-MMP may play a key role in human breast carcinoma invasion and metastasis by being predominantly responsible for activation of proMMP-2.

Abstract: