Connective tissue growth factor/CCN2 overexpression in mouse synovial lining results in transient fibrosis and cartilage damage

OBJECTIVE: Characteristics of osteoarthritis (OA) include cartilage damage, fibrosis, and osteophyte formation. Connective tissue growth factor (CTGF; also known as CCN2), is found in high levels in OA chondrocytes and is frequently involved in fibrosis, bone formation, and cartilage repair. The present study was therefore undertaken to investigate the potential role of CTGF in OA pathophysiology. METHODS: We transfected the synovial lining of mouse knee joints with a recombinant adenovirus expressing human CTGF and measured synovial fibrosis and proteoglycan content in cartilage on days 1, 3, 7, 14, and 28. Messenger RNA (mRNA) expression in synovium and cartilage was measured on days 3, 7, and 21. RESULTS: CTGF induced synovial fibrosis, as indicated by accumulation of extracellular matrix and an increase in procollagen type I-positive cells. The fibrosis reached a maximum on day 7 and had reversed by day 28. Levels of mRNA for matrix metalloproteinase 3 (MMP-3), MMP-13, ADAMTS-4, ADAMTS-5, tissue inhibitor of metalloproteinases 1 (TIMP-1), and transforming growth factor beta were elevated in the fibrotic tissue. TIMP-1 expression was elevated on day 3, while expression of other genes did not increase until day 7 or later. CTGF induced proteoglycan depletion in cartilage as early as day 1. Maximal depletion was observed on days 3-7. Cartilage damage was reduced by day 28. A high level of MMP-3 mRNA expression was found in cartilage. CTGF overexpression did not induce osteophyte formation. CONCLUSION: CTGF induces transient fibrosis that is reversible within 28 days. Overexpression of CTGF in knee joints results in reversible cartilage damage, induced either by the high CTGF levels or via factors produced by the CTGF-induced fibrotic tissue.     

Expression of MMP-1 in cartilage and synovium of experimentally induced rabbit ACLT traumatic osteoarthritis: immunohistochemical study

To observe the level and the distribution of MMP-1 in cartilage and synovium over the progression of OA in rabbit ACLT model, and to explore the relationship between the amount of MMP-1 expression and the degree of OA cartilage degradation. OA was induced in 20 rabbits by anterior cruciate ligament transection (ACLT) and ten rabbits were killed at 4 and 8 weeks after the operation, respectively. A further ten rabbits received unilateral knee arthrotomy as controls. Cartilage degradation was observed under dissecting microscope, immunohistochemical, and morphometric analysis were adopted to record the tissue level and distribution of MMP-1 in cartilage and synovium. Cartilage degradation in both ACLT groups was more severe than that in control group, and the degradation in 8-week ACLT group was more severe than that in 4-week ACLT group. MMP-1 was expressed predominantly in the superficial and upper intermediate layers of cartilage and in the lining layer of synovium. Its expression was increased steadily over the progression of OA both in cartilage and in synovium, but there was a little difference in the increase pattern between them: increase of MMP-1 in synovium lagged behind that in cartilage in early stage of OA. Conclusion: MMP-1 was involved in OA development in rabbit ACLT model and the amount of its expression was related with the degree of cartilage degradation. The increase of MMP-1 expression in synovium lagged behind that in cartilage, suggesting OA pathology was originated from cartilage, but synovitis may also paticipate in cartilage degradation, especially in middle and late stage of OA. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of low intensity pulsed ultrasound on expression of TIMP-2 in serum and expression of mmp-13 in articular cartilage of rabbits with knee osteoarthritis

Objective:To study the effect of low intensity pulsed ultrasound(LIPUS) on the expression of tissue inhibitor of metalloproteinase-2(TIMP-2) in the serum and expression of matrix metallopeptidase 13(MMP-13) in the articular cartilage cells of rabbits with knee osteoarthritis(OA).Methods:Inner patellar ligament defect method was used to establish the model of knee OA.Four weeks after the modeling,the arterial blood was drawn from the ear of each rabbit,while ELISA was employed to detect the expression of TIMP-2 in the serum.The chondrocytes were separated from animals in each group and then cultured in vitro.All rabbits were divided into control group,OA model group and OA + LIPUS group.Cells in the control and OA groups were not treated,while cells in the OA+ LIPUS group were treated with LIPUS(40 mW/cnr.1 time/day).Cells were collected 7 d later and the RNA and total protein were extracted respectively.Real-time PCR and Western blotting were employed to analyze the expression of MMP-13 in chondrocytes at the mRNA and protein level,respectively.Results:The success rate of establishment of OA model was 83%.The results of ELISA showed that the content of TIMP-2 in the serum of animals with OA was 22.3%,lower than the one in the control group(P0.05).Compared with the normal control group,the expression of TIMP-2in the OA model group was significantly increased,while the expression of MMP-13 was significantly increased(P0.05).After the stimulation of LIPUS,the expression of TIMP-2 and MMP-13 was close to the one in the normal control group.Conclusions:The inner patellar ligament defect method is a mature method to establish the rabbit OA model,with high success rate.The expression of serum TIMP-2 in the OA model group is significantly decreased.LIPUS can up-regulate TIMP-2 and down-regulate MMP-13.     

Expression of the tissue inhibitor of metalloproteinases (TIMP) gene family in normal and osteoarthritic joints

The pathophysiological and biological significance of tissue inhibitor of the metalloproteinases-3 (TIMP-3) gene compared to other TIMPs was investigated in osteoarthritic (OA) human and normal bovine joint tissues. Human OA synovial fibroblasts in culture constitutively expressed TIMP mRNAs. TIMP-3, TIMP-1 and gelatinase A mRNAs were elevated in most human OA synovia over controls, while TIMP-2 expression was similar. TIMP-3 and TIMP-1 mRNAs present in bovine cartilage were inducible by serum factors. Transforming growth factor beta (TGF-β1) induced TIMP-3 RNA and protein in human OA and normal bovine chondrocytes. TIMP mRNAs were low (TIMP-1) or undetectable in human fetal chondrocytes but were expressed at all other ages. Thus, the two main joint tissues, synovial membranes and cartilage, express TIMP genes. Due to their matrix protecting activities, the presence of multiple TIMPs may be beneficial for normal joints, while increased TIMP-3 and TIMP-1 expression in arthritic joints may be associated with pathological remodeling. Received: 13 October 1998 / Accepted: 18 February 1999     

Trichostatin A inhibits expression of cathepsins in experimental osteoarthritis

The aim of this study was to investigate the effects of trichostatin A (TSA) on expression of cathepsins in cartilage in experimental osteoarthritis (OA). OA was induced in 18 rabbits by bilateral anterior cruciate ligament transection (ACLT). Four weeks after surgery, rabbits received intra-articular injection with TSA dissolved in the dimethylsulphoxide (DMSO) in the right knees and DMSO in the left knees once a week for 5 weeks. Rabbits were killed 7 days after the last injection. The knee joints were assessed by morphological and histological examination. Messenger RNA expression of cathepsins K, B, L, S and cystatin C was studied by real-time PCR. TSA inhibited the expression of cathepsins K, B, L, S and cystatin C accompanied with the less degradation in cartilage. The results suggest that TSA exhibits protective effects against cartilage degradation in rabbits with OA and the effects may be associated with the inhibition of cathepsins.     

Astaxanthin ameliorates cartilage damage in experimental osteoarthritis

Abstract

Purpose. Astaxanthin is a red-pigment carotenoid found in certain marine animals and plants. Astaxanthin has been shown to inhibit matrix metalloproteinases (MMPs) expression in vitro. However, the effect of astaxanthin on cartilage is still unclear. The aim of this study was to investigate the effects of astaxanthin on cartilage in experimental osteoarthritis (OA).

Methods. New Zealand rabbits underwent anterior cruciate ligament transection to induce OA in right knee. Rabbits received intra-articular injection containing 0.3 ml of vehicle (dimethyl sulfoxide) or astaxanthin (50 μM). Injection was started on the day of operation, and the injection were performed once weekly for six consecutive weeks. Then, rabbits were sacrificed and the right knees were harvested for study.

Results. Cartilage degradation was reduced by astaxanthin, as assessed by morphological and histological examination. Astaxanthin inhibited the gene expression of MMP-1, MMP-3, and MMP-13 in cartilage as compared with the vehicle group.

Conclusions. The results suggest that astaxanthin may be considered as pharmaceutical agent in OA treatment.     

盘状结构域受体2与软骨破坏程度的相关研究

目的 观察盘状结构域受体(DDR)2和基质金属蛋白酶(MMP)-13在膝骨关节炎(OA)大鼠不同时期软骨及滑膜中的表达,探讨DDR2与关节软骨破坏之间的关系.方法 采用改良膝关节腔内注射木瓜蛋白酶法制作OA大鼠模型,从蛋白水平检测造模后不同病理阶段关节软骨及滑膜中DDR2和MMP-13的表达规律和分布特点.结果 DDR2在各模型组关节软骨及滑膜中的表达较健康组增高(P＜0.01),并且各组中软骨表达高于相应滑膜,MMP-13表达呈现与DDR2相同的特点,二者相关系数r=0.93(P＜0.01).结论 初步证明"DDR2-MMP-13-软骨破坏"途径在OA病理过程中起重要作用.软骨和滑膜DDR2的表达升高共同促进软骨退变.     

壳聚糖膝关节腔内注射疗法对兔骨关节炎关节软骨的影响

目的观察关节内注射羧甲基壳聚糖(CMCTS)对兔骨关节炎(OA)关节软骨退变及软骨基质金属蛋白酶(MMP)-1,-3mRNA表达的影响。方法24只大耳白兔行单侧膝关节前交叉韧带切断术,术后5周将动物随机分为3组,A组关节内注射2%CMCTS0.3ml,每2周1次;B组关节内注射1%透明质酸钠(HA)0.3ml,每周1次;C组关节内不注射药物。术后11周处死动物,观察各组股骨内髁关节软骨的大体变化,采用反转录-聚合酶链反应(RT-PCR)方法检测股骨内髁退变软骨中MMP-1和MMP-3的mRNA表达。结果CMCTS和HA注射组软骨退变程度较不用药组明显减轻,CMCTS注射组软骨MMP-1、MMP-3的mRNA表达明显低于HA注射组和不用药组。HA注射组软骨MMP-1和MMP-3的mRNA表达与不用药组比较,差异没有显著性意义。结论CMCTS能够明显抑制OA软骨MMP-1和MMP-3的mRNA表达,明显减轻软骨退变的程度,CMCTS对早期OA软骨有修复保护作用。     

Phonoarthrography,musculoskeletal ultrasonography,and biochemical biomarkers for the evaluation of knee cartilage in osteoarthritis

The aim of this study was to examine the relationship among three different parameters used to assess cartilage in osteoarthritis (OA) of the knee. These parameters are phonoarthrography (Phono-A), musculoskeletal ultrasonography (MSUS) from the 4 condyles, and biochemical markers; notably, matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of proteinase (TIMP-1). A total of 100 knees with chronic idiopathic OA diagnosed according to the American College of Rheumatology (ACR) criteria were studied, together with 50 normal knees. The knee sounds were recorded by Phono-A and the cartilage thickness was measured by MSUS. All patients and controls had MMP-3 and TIMP-1 measured in a blood sample, using an enzyme-linked immunosorbent assay (ELISA). Conventional knee X-rays were obtained for diagnosis and for Kellgren–Lawrence (K-L) grading purposes. The results showed that Phono-A values were inversely correlated with cartilage thickness, both of these being sensitive parameters for cartilage degeneration. Phono-A values were higher in patients than in controls, denoting more degeneration of cartilage, and the cartilage thickness of all 4 condyles showed significant reductions in patients compared with normal controls. Most of the patients were categorized as grade 2 (36%) and grade 3 (30%) of the K-L classification. Mean levels of MMP-3 and TIMP-1 were significantly elevated in both groups but they were not correlated with each other. MMP-3 continued to rise with increasing radiological grades until grade 4, where it fell unexpectedly. In conclusion, Phono-A and cartilage thickness measured by MSUS seem to support each other. They can be used as parameters for following up cartilage in OA of the knees. The first deals with the roughness of the cartilage surface and the second with its thickness, complementing each other. MMP-3 continues to rise in early and middle grades of OA, denoting cartilage destruction.     

Quantitation of metalloproteinase gene expression in rheumatoid and psoriatic arthritis synovial tissue distal and proximal to the cartilage-pannus junction

OBJECTIVE: The distinct and different patterns of radiological damage in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) may be a product of the relative balance of proteolytic enzyme and inhibitor gene expression in synovial tissue. This study compared metalloproteinase gene expression in synovium located proximal to the cartilage-pannus junction (CPJ) and distal to the CPJ (non-CPJ) in patients with PsA and RA. METHODS: Synovial biopsies were obtained from CPJ and non-CPJ sites under direct vision at arthroscopy of an inflamed knee in patients with PsA (n = 12) and RA (n = 12) who were not under disease modifying antirheumatic drug treatment. A competitive, quantitative RT-PCR technique was established for synovial RNA using a polycompetitor construct containing mRNA-specific primer sites for collagenase (MMP-1), stromelysin (MMP-3), tissue inhibitor of metalloproteinase-1 (TIMP-1), and GAPDH. cDNA products were separated and quantified by ethidium bromide stained gel electrophoresis and mRNA values were normalized relative to GAPDH expression. RESULTS: MMP-1, MMP-3, and TIMP-1 mRNA were upregulated in RA and PsA synovium with a prodestructive (MMP-1 + MMP-3)/TIMP-1 balance in both diseases. Similar levels of MMP mRNA expression were observed in PsA and RA despite the presence of less radiological erosion in the PsA group. No difference was observed in the degree of upregulation of MMP-1, MMP-3, or TIMP-1 mRNA in paired biopsies from CPJ and non-CPJ sites in either PsA (n = 8) or RA (n = 10). The ratio of TIMP-1 expression in CPJ compared to non-CPJ biopsies was higher in patients with nonerosive disease (10.1 +/- 27.8) than in erosive patients (0.75 +/- 0.27; p = 0.07). CONCLUSION: PsA and RA have similar levels of MMP-1, MMP-3, and TIMP-1 mRNA expression in synovium. There is no evidence of increased metalloproteinase mRNA expression at the CPJ in RA or PsA. The different patterns of radiological progression seen in RA and PsA were not explained by differences in synovial mRNA expression of MMP-1, MMP-3, or TIMP-1.     

葛根素对兔动脉粥样硬化基质金属蛋白酶-9及其组织抑制物-1表达的影响

目的：观察葛根素对动脉粥样硬化兔髂动脉分泌和表达基质金属蛋白酶-9（MMP-9）及其组织抑制物-1（TIMP-1）的影响。方法：20只家兔分为正常对照组（正常饮食，6只）、病理对照组（球囊和高脂饮食，8只）和葛根素组（球囊、高脂饮食和葛根素，8只）。球囊损伤后4周处死，取一侧病变髂动脉做病理切片，应用免疫组化法测定MMP-9和TIMP-1的蛋白表达；取另一侧病变髂动脉抽提总RNA应用半定量逆转录多聚酶链式反应（RT—PCR）测定MMP-9和TIMP-1 mRNA的表达。结果：兔动脉粥样斑块MMP-9 mRNA（mRNA／GAP—DH mRNA）表达：正常对照组、病理对照组、葛根素组的分别为0．81±0．17，1．52±0．24，1.03±0．19，病理对照组、葛根素组的较正常对照组显著增加（P〈0．05），而葛根素组的较病理对照组显著下降（P〈0．05），上述三组的TIMP—1 mRNA的表达依次为1．44±0．14，2．63±0．16，2．67±0．12，病理对照组与葛根素组的较正常对照组显著增加（P〈0．05），但病理对照组与葛根素组间无显著差异（P〉0．05）。免疫组化检测显示葛根素抑制MMP-9蛋白质表达（P〈0．05），但对TIMP-1蛋白质的表达无影响。结论：葛根素可能是通过调节兔动脉粥样斑块分泌MMP-9途径发挥稳定动脉粥样硬化斑块的作用。     

Effects of dehydroepiandrosterone on articular cartilage during the development of osteoarthritis

OBJECTIVE: To investigate the in vivo effects of dehydroepiandrosterone (DHEA) on knee joints during the development of experimentally induced osteoarthritis (OA). METHODS: Twenty-two mature NZW rabbits underwent bilateral anterior cruciate ligament transection (ACLT) and received 0.3-ml intraarticular injections of DHEA (at a concentration of 100 microM in phosphate buffered saline) and control solution in the right and left knees, respectively, beginning 4 weeks after ACLT and continuing once weekly for 5 weeks. All animals were killed 9 weeks after surgery, and the knee joints were assessed by gross morphologic, histologic, histomorphometric, and biochemical methods. RESULTS: Gross morphologic inspection following India ink application showed that the right femoral condyles, which received DHEA, demonstrated less severe cartilage damage than did the contralateral condyles. The thickness, area, and roughness of the DHEA-treated femoral condyles provided evidence of a cartilage-protecting effect of DHEA following ACLT. These results were supported by gene expression analysis. Messenger RNA expression of a proinflammatory cytokine, interleukin-1beta, and catabolic enzymes, matrix metalloproteinases 1 and 3, was reduced in the cartilage of the DHEA-treated knee joints, and expression of tissue inhibitor of metalloproteinase 1 was increased. CONCLUSION: Results of the present study demonstrate a cartilage-protecting effect of DHEA during the development of OA following ACLT in a rabbit model.     

In vivo expression of stromelysin in synovium and cartilage of rabbits injected intraarticularly with interleukin-1β

Objective. To examine the in vivo expression of the matrix metalloproteinase stromelysin in the synovium and articular cartilage of rabbits injected intraarticularly with recombinant human interleukin-1β (IL-1). Methods. The direct isolation of messenger RNA (mRNA) from articular cartilage without the prior isolation of chondrocytes is described. The in vivo expression of stromelysin was examined at the mRNA level by Northern blot analysis, and at the protein level by in situ immunolocalization and by enzyme-linked immunosorbent assay. Results. In the synovium of IL-1–injected joints, stromelysin mRNA levels were highest at 4 hours and declined to background levels within 24 hours. In the cartilage of IL-1–injected joints, stromelysin mRNA was elevated at 4 hours and continued to increase until 8 hours, before declining. Stromelysin mRNA expression preceded a similar increase in stromelysin protein levels in both synovium and cartilage. Conclusion. Intraarticular injection of IL-1 induced the endogenous expression of stromelysin mRNA and protein in both synovium and cartilage. The kinetics of stromelysin expression correlated well with the accumulation of stromelysin and proteoglycan in synovial fluids. Therefore, the de novo synthesis of stromelysin in cartilage may have contributed to the loss of proteoglycan from that tissue.     

Induction of vascular endothelial growth factor and matrix metalloproteinase-3 (stromelysin) by interleukin-1 in human articular chondrocytes and synoviocytes

We investigated the effects of interleukin (IL)-1 on vascular endothelial growth factor (VEGF) and matrix metalloproteinase-3 (MMP-3) (stromelysin) secretion from chondrocytes and synoviocytes in different clinical conditions. Specifically, cells obtained from osteoarthritic (OA) (n=7), rheumatoid arthritic (RA) (n=5), and post-traumatic (PT) (n=5) patients were stimulated in vitro with IL-1 in the presence or absence of an IL-1 receptor antagonist (IL-1ra) (anakinra). Levels of secreted MMP-3 and VEGF were measured by enzyme-linked immunosorbent assay. The VEGF mRNA expression was analyzed quantitatively. Interleukin-1 induced both VEGF and MMP-3 secretion from all of the samples tested, and VEGF mRNA expression was also upregulated. Interleukin-1ra significantly suppressed the enhancing effect of IL-1 on MMP-3 and VEGF in both cell types. In conclusion, IL-1 simultaneously induces MMP-3 and VEGF production from chondrocytes and synoviocytes in inflammatory, degenerative, and post-traumatic joints. Therefore, IL-1ra might be beneficial for protection from VEGF-mediated alterations of cartilage metabolism in pathologic and physiologic conditions.     

In vivo expression of stromelysin in synovium and cartilage of rabbits injected intraarticularly with interleukin-1 beta.

OBJECTIVE. To examine the in vivo expression of the matrix metalloproteinase stromelysin in the synovium and articular cartilage of rabbits injected intraarticularly with recombinant human interleukin-1 beta (IL-1). METHODS. The direct isolation of messenger RNA (mRNA) from articular cartilage without the prior isolation of chondrocytes is described. The in vivo expression of stromelysin was examined at the mRNA level by Northern blot analysis, and at the protein level by in situ immunolocalization and by enzyme-linked immunosorbent assay. RESULTS. In the synovium of IL-1-injected joints, stromelysin mRNA levels were highest at 4 hours and declined to background levels within 24 hours. In the cartilage of IL-1-injected joints, stromelysin mRNA was elevated at 4 hours and continued to increase until 8 hours, before declining. Stromelysin mRNA expression preceded a similar increase in stromelysin protein levels in both synovium and cartilage. CONCLUSION. Intraarticular injection of IL-1 induced the endogenous expression of stromelysin mRNA and protein in both synovium and cartilage. The kinetics of stromelysin expression correlated well with the accumulation of stromelysin and proteoglycan in synovial fluids. Therefore, the de novo synthesis of stromelysin in cartilage may have contributed to the loss of proteoglycan from that tissue.     

老年骨关节炎患者关节软骨和滑膜中转化生长因子β及受体和金属蛋白酶组织抑制物的研究

目的 探讨骨关节炎（OA）患者关节软骨和滑膜中转化生长因子β（TGFβ1）、转化生长因子β受体（TGFβR）和金属蛋白酶组织抑制物－1（TIMP－1）变化及其与OA发病的关系。方法 采用免疫组化方法检测23例老年OA患者及3例外伤患者正常关节软骨和滑膜TGFβ1、转化生长因子βI类受体（TGFβRI）、转化生长因子βⅡ类受体（TGFβRⅡ）和TIMP－1的分布和阳性程度。结果 OA患者中14例关节软骨和16例滑膜TGFβ1染色呈阳性或弱阳性,14例关节软骨和15例滑膜TIMP－1染色呈弱阳性,全部OA患者关节软骨和滑膜TGFβRI和TGFβRⅡ染色呈强阳性。阳性细胞包括软骨细胞、滑膜衬里细胞、滑膜下层的血管内皮细胞和间质巨噬细胞等。结论 老年OA患者关节软骨和滑膜中TGFβ1、TGFβ及TIMP－1的变化可能与OA发病有一定的关系。     

Differential expression patterns of matrix metalloproteinases and their inhibitors during development of osteoarthritis in a transgenic mouse model

Objective: To characterise the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) during degeneration of articular cartilage in a transgenic Del1 mouse model for osteoarthritis.

Methods: Northern analysis was used to measure mRNA levels of MMP-2, -3, -8, -9, -13, and -14, and TIMP-1, -2, and -3 in total RNA extracted from knee joints of transgenic Del1 mice, harbouring a 15 amino acid deletion in the triple helical domain of the α1(II) collagen chain, using their non-transgenic littermates as controls. Immunohistochemistry was used to study the presence of cleavage products (neoepitopes) of type II collagen, and the distribution of MMP-13 and TIMP-1 in degenerating cartilage.

Results: Each of the MMP and TIMP mRNAs analysed exhibited distinct expression patterns during development and osteoarthritic degeneration of the knee joint. The most striking change was up regulation of MMP-13 mRNA expression in the knee joints of Del1 mice at the onset of cartilage degeneration. However, the strongest immunostaining for MMP-13 and its inhibitor TIMP-1 was not seen in the degenerating articular cartilage but in synovial tissue, deep calcified cartilage, and subchondral bone. The localisation of type II collagen neoepitopes in chondrocytes and their pericellular matrix followed a similar pattern; they were not seen in cartilage fibrillations, but in adjacent unaffected cartilage.

Conclusion: The primary localisation of MMP-13 and TIMP-1 in hyperplastic synovial tissue, subchondral bone, and calcified cartilage suggests that up regulation of MMP-13 expression during early degeneration of articular cartilage is a secondary response to cartilage erosion. This interpretation is supported by the distribution of type II collagen neoepitopes. Synovial production of MMP-13 may be related to removal of tissue debris released from articular cartilage. In the deep calcified cartilage and adjacent subchondral bone, MMP-13 probably participates in tissue remodelling.

     

Matrix metalloproteinase-3 secretion from human colonic subepithelial myofibroblasts: role of interleukin-17

Background. Subepithelial myofibroblasts (SEMFs) play a role in extracellular matrix (ECM) metabolism in the colon. In this study, we investigated the effects of interleukin (IL)-17, IL-1β, and tumor necrosis factor (TNF)-α on matrix metalloproteinase (MMP)-3 secretion in colonic SEMFs. Methods. MMP-3 secretion and MMP-3 mRNA expression were determined by Western and Northern blotting, respectively. The secretion of tissue inhibitor of matrix metalloproteinase (TIMP)-1 was determined by enzyme-linked immunosorbent assay (ELISA). Results. In human colonic SEMFs, MMP-3 secretion and MMP-3 mRNA expression were induced by IL-17, IL-1β, and TNF-α. The effect of IL-17 was observed, but this was weak as compared with those induced by IL-1β or TNF-α. A c-Jun/activating protein-1 (AP-1) inhibitor, curcumin, reduced the IL-17-, IL-1β-, and TNF-α-induced MMP-3 mRNA expression, and mitogen-activated protein (MAP) kinase inhibitors (U0126, PD098059, and SB203580) also blocked MMP-3 secretion. There findings indicate a role for AP-1 and MAP kinases in cytokine-induced MMP-3 secretion. Furthermore, costimulation by IL-17 + IL-1β and by IL-17 + TNF-α induced a marked increase in MMP-3 secretion. The costimulatory effects of these combinations were also observed for TIMP-1 mRNA expression and TIMP-1 secretion. Conclusions. Colonic SEMFs actively secreted MMP-3 in response to IL-17, IL-1β, and TNF-α. This was coupled with TIMP-1 secretion. Colonic SEMFs may play an important role in ECM turnover via MMP secretion. Received: July 2, 2002 / Accepted: December 18, 2002 RID="*" ID="*" Reprint requests to: A. Andoh