[Molecular and cellular basis of joint destruction in rheumatoid arthritis].
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Publications and source records attributed to R E Gay.
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Rheumatoid arthritis (RA) is a chronic autoimmune-disease of unknown origin that primarily affects the joints and ultimately leads to their destruction. The involvement of immune cells is a general hallmark of autoimmune-related disorders. In this regard, macrophages, T cells and their respective cytokines play a pivotal role in RA. However, the notion that RA is a primarily T-cell-dependent disease has been strongly challenged during recent years. Rather, it has been understood that resident, fibroblast-like cells contribute significantly to the perpetuation of disease, and that they may even play a role in its initiation. These rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints. A number of studies have demonstrated that RASFs show alterations in morphology and behaviour, including molecular changes in signalling cascades, apoptosis responses and in the expression of adhesion molecules as well as matrix-degrading enzymes. These changes appear to reflect a stable activation of RASFs, which occurs independently of continuous exogenous stimulation. As a consequence, RASFs are no longer considered passive bystanders but active players in the complex intercellular network of RA.
OBJECTIVES: The study was designed to investigate the analgesic effects and mechanisms of acetaminophen (paracetamol) in symptomatic osteoarthritis (OA) of the knee. METHODS: Twenty patients with symptomatic OA were randomly allocated to two groups treated with either acetaminophen or rofecoxib for 3 months. Visits and measurements were scheduled upon entry (T0), at month 1 (T1) and at month 3 (T3). The intensity of joint pain was evaluated with a 100-mm visual analogue scale (VAS). The physical function of the affected knee was evaluated with a questionnaire comparable to the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). Levels of serotonin, substance P (SP) and beta-endorphin (BEND) were determined with commercial enzyme-linked immunoassay kits. The expression of kappa opioid receptor (KOR) in peripheral mononuclear blood cells (PBMCs) was quantified by real-time PCR. RESULTS: Both acetaminophen and rofecoxib relieved pain considerably but with different kinetics, and affected different biomarkers. Rofecoxib appeared to be more efficient, reducing pain intensity by 56% at T1 (P<0.01), whereas acetaminophen reduced it by only 29%. Physical function improved in both groups by T3. Correlated with the pain relief, acetaminophen significantly reduced plasma BEND levels, whereas rofecoxib did not do so. In both groups plasma SP levels were elevated compared with T0. A reduction in serum serotonin was detected in the rofecoxib group at T1 (P=0.004) but had recovered at T3. No changes in KOR mRNA in PBMCs were observed in either group. CONCLUSIONS: There is a correlation between reduction in circulating BEND and OA pain relief in patients treated with acetaminophen.
The metastasis-associated protein S100A4 promotes the progression of cancer by regulating the remodelling of the extracellular matrix. The expression of S100A4 in vivo is shown and the functional role of S100A4 in the pathogenesis of osteoarthritis and rheumatoid arthritisis is explored. The expression of S100A4 in rheumatoid arthritis, osteoarthritis and normal synovial tissues was determined by immunohistochemistry. The expression of matrix metalloproteinase (MMP) mRNA was measured in rheumatoid arthritis and osteoarthritis synovial fibroblasts treated and untreated with S100A4 oligomer by real-time polymerase chain reaction. Levels of released MMPs were confirmed by ELISA in cell culture supernatants. S100A4 protein was expressed in rheumatoid arthritis and osteoarthritis synovial tissues, in contrast with normal synovium. S100A4 up regulated MMP-3 mRNA in rheumatoid arthritis synovial fluid, with a peak after 6 h. This resulted in release of MMP-3 protein. MMP-1, MMP-9 and MMP-13 mRNA were also up regulated in synovial fluid, but with different kinetics. MMP-14 mRNA showed no change. Thus, S100A4 protein is expressed in synovial tissues of patients with rheumatoid arthritis and osteoarthritis in contrast with healthy people. It induces the expression and release of MMP-3 and other MMPs from synovial fluid. The data suggest that S100A4-producing cells could be involved in the pathogenesis of osteoarthritis and rheumatoid arthritis, including pannus formation and joint destruction.
BACKGROUND: Histone acetylation/deacetylation has a critical role in the regulation of transcription by altering the chromatin structure. OBJECTIVE: To analyse the effect of trichostatin A (TSA), a streptomyces metabolite which specifically inhibits mammalian histone deacetylases, on TRAIL-induced apoptosis of rheumatoid arthritis synovial fibroblasts (RASF). METHODS: Apoptotic cells were detected after co-treatment of RASF with TRAIL (200 ng/ml) and TSA (0.5, 1, and 2 micromol/l) by flow cytometry using propidium iodide/annexin-V-FITC staining. Cell proliferation was assessed using the MTS proliferation test. Induction of the cell cycle inhibitor p21Waf/Cip1 by TSA was analysed by western blot. Expression of the TRAIL receptor-2 (DR5) on the cell surface of RASF was analysed by flow cytometry. Levels of soluble TRAIL were measured in synovial fluid of patients with RA and osteoarthritis (OA) by ELISA. RESULTS: Co-treatment of the cells with TSA and TRAIL induced cell death in a synergistic and dose dependent manner, whereas TRAIL and TSA alone had no effect or only a modest effect. RASF express DR5 (TRAIL receptor 2), but treatment of the cells with TSA for 24 hours did not change the expression level of DR5, as it is shown for cancer cells. TSA induced cell cycle arrest in RASF through up regulation of p21Waf1/Cip1. Levels of soluble TRAIL were significantly higher in RA than in OA synovial fluids. CONCLUSION: Because TSA sensitises RASF for TRAIL-induced apoptosis, it is concluded that TSA discloses sensitive sites in the cascade of TRAIL signalling and may represent a new principle for the treatment of RA.
BACKGROUND: Galectin-3 is expressed in the synovial tissue of patients with rheumatoid arthritis (RA), particularly at sites of joint destruction. OBJECTIVE: To explore the possibilities that galectin-3 is induced either by proinflammatory cytokines or by adhesion to cartilage components. METHODS: Cell culture plates were coated with fibronectin, collagens I-VI, or cartilage oligomeric matrix protein (COMP), and the suspended cells were then added. The medium was changed after 1 hour at 37 degrees C. Adherent cells were further incubated for 18 hours in the presence or absence of tumour necrosis factor alpha (TNF alpha) or interleukin 1 beta. Cells were pretreated with murine IgG1, anti-CD29, -CD51, -CD61 (integrins), or -CD3 monoclonal antibodies and transferred to culture plates coated with COMP. Adherent cells were counted by light microscopy. The expression of intracellular galectin-3, or cell surface CD29, CD51, and CD61 was determined by flow cytometry before and after adhesion. RESULTS: Four times more RA synovial fibroblasts (SF) than osteoarthritis SF adhered to COMP. RA SF presented more cell surface integrins, and monoclonal antibodies against CD51 inhibited the adhesion to COMP by 80%. TNF alpha reduced the expression of CD61 and the adhesion to COMP, but did not reverse the adhesion once it had taken place. The adhesion of RA SF to COMP was found to increase the intracellular level of galectin-3. In contrast, intracellular galectin-3 decreased after exposure to TNF alpha. CONCLUSION: The increase of galectin-3 occurs after adhesion to COMP, and the alpha V beta 3 receptor (CD51/CD61) has a pivotal role in this process.
The present study was undertaken to examine whether ribozymes cleaving specifically cathepsin L (CL) mRNA are able to decrease the synthesis of CL protease in rheumatoid arthritis synovial fibroblasts (RA-SF) and thereby reduce the invasiveness into cartilage both in vitro and in the SCID mouse coimplantation model of RA. Two different ribozymes that cleave CL mRNA specifically at positions 533 (RzCL533) and 790 (RzCL790) were generated. Using retroviral gene transfer, RA-SF were transduced with the ribozyme constructs or the empty vector. To examine the effect of the ribozymes on the mRNA level, quantitative analysis for CL mRNA was performed using real-time PCR. For evaluation on the protein level, ELISA using specific anti-CL antibodies was performed. In addition, transduced RA-SF were examined in vitro in a three-dimensional destruction assay evaluating their ability to degrade extracellular matrix produced by human chondrocytes. Matrix destruction was monitored by the release of soluble glycosaminoglycans (sGAG). Using the in vivo SCID mouse coimplantation model of RA, RzCL533-transduced RA-SF and control cells were coimplanted with human cartilage for 60 days. After being killed, invasion of RA-SF into the cartilage was evaluated by using a semiquantitative score. Transduction of RA-SF with RzCL533 and RzCL790 ribozymes decreased significantly the expression of CL mRNA to 44% (range 25-62%) and 20% (range 1-43%), respectively, when compared to mock-transduced cells. The protein concentration of CL in the cell culture supernatants of transduced RA-SF was decreased from 16.0 ng/ml in the mock constructs to 4.1 and 8.2 ng/ml (mean), respectively. Using the in vitro cartilage destruction assay, the release of sGAG decreased to 46 and 60%, respectively, after 14 days when compared to mock-transduced cells. In the SCID mouse coimplantation model of RA, RzCL533-transduced RA-SF revealed a significant lower cartilage invasion when compared to mock and untransduced cells. Using retroviral gene transfer, ribozymes cleaving CL mRNA inhibit specifically the synthesis of this matrix-degrading enzyme and reduce cartilage destruction in in vitro and in vivo models. Our study therefore suggests that ribozymes targeting CL could be a novel and efficient tool to inhibit joint destruction in RA.
OBJECTIVE: To determine whether there is evidence of increased DNA fragmentation and ultrastructural changes in muscle tissue of patients with fibromyalgia (FM) compared with healthy controls. METHODS: Muscle tissues from 10 community residents with FM and 10 age and sex matched healthy controls were examined "blindly" for the presence of DNA fragmentation by two different methods: terminal deoxynucleotidyl transferase (TdT) staining (TUNEL) and the FragEL-Klenow DNA fragmentation detection kit. Ultrastructural analysis of tissue was performed by electron microscopy. RESULTS: DNA fragmentation was detected by both methods in 55.4 (SEM 2.5)% of the nuclei in muscle tissue of patients with FM compared with 16.1 (4.1)% (p<0.001) of the nuclei in healthy controls. Contrary to expectation, no typical features of apoptosis could be detected by electron microscopy. The myofibres and actin filaments were disorganised and lipofuscin bodies were seen; glycogen and lipid accumulation were also found. The number of mitochondria was significantly lower in patients with FM than in controls and seemed to be morphologically altered. CONCLUSION: The ultrastructural changes described suggest that patients with FM are characterised by abnormalities in muscle tissue that include increased DNA fragmentation and changes in the number and size of mitochondria. These cellular changes are not signs of apoptosis. Persistent focal contractions in muscle may contribute to ultrastructural tissue abnormalities as well as to the induction and/or chronicity of nociceptive transmission from muscle to the central nervous system.
OBJECTIVE: To investigate the expression of maspin in RA synovial tissue and compare it with the expression in osteoarthritis (OA) and normal synovial tissue (NS). METHODS: Using specific primers for maspin, a 237 bp fragment was amplified from cDNA obtained from cultured RA, OA, and normal synovial fibroblasts (SF) by RT-PCR. Additionally, mRNA expression levels were determined quantitatively by real time PCR. mRNA expression of maspin was investigated on snap frozen and paraffin embedded synovial tissue sections by in situ hybridisation. Immunohistochemistry was used to identify the cell type expressing maspin. SDS-PAGE and western blotting were performed to evaluate the protein expression in cultured SF. To confirm protein synthesis in situ, immunohistochemistry with specific anti-maspin antibodies was performed in synovial tissue sections of patients with RA. RESULTS: RT-PCR showed expression of maspin in all cDNA samples from cultured SF. Maspin mRNA was found to be decreased in RA SF twofold and 70-fold compared with OA SF and NS SF, respectively. Maspin mRNA was expressed in RA, OA, and normal synovial tissue. Importantly, maspin transcripts were also found at sites of invasion into cartilage and bone. At the protein level, maspin could be detected in RA and, less prominently, OA SF. In RA synovial tissue, maspin protein was detected in only a few synovial lining cells. CONCLUSION: Maspin is expressed intensively in RA SF at the mRNA level, but only slightly at the protein level, possibly owing to down regulation of maspin; this may contribute to the hyperplasia of synovial tissue in RA.
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Matrix metalloproteinases (MMPs) are believed to be pivotal enzymes in the invasion of articular cartilage by synovial tissue in rheumatoid arthritis (RA). Here, we investigated the effects of gene transfer of tissue inhibitors of metalloproteinases (TIMPs) on the invasiveness of RA synovial fibroblasts (RASF) in vitro and in vivo. Adenoviral vectors (Ad) were used for gene transfer. The effects of AdTIMP-1 and AdTIMP-3 gene transfer on matrix invasion were investigated in vitro in a transwell system. Cartilage invasion in vivo was studied in the SCID mouse co-implantation model for 60 days. In addition, the effects of AdTIMP-1 and AdTIMP-3 on cell proliferation were investigated. A significant reduction in invasiveness was demonstrated in vitro as well as in vivo in both the AdTIMP-1- and AdTIMP-3-transduced RASF compared with untransduced SF or SF that were transduced with control vectors. in vitro, the number of invading cells was reduced to 25% (P<0.001) in the AdTIMP-1-transduced cells and to 13% (P<0.0001) in the AdTIMP-3-transduced cells (% of untransduced cells). Cell proliferation was significantly inhibited by AdTIMP-3 and, less, by AdTIMP-1. In conclusion, overexpression of TIMP-1 and TIMP-3 by Ad gene transfer results in a marked reduction of the invasiveness of RASF in vitro and in the SCID mouse model. Apart from the inhibition of MMPs, a reduction in proliferation rate may contribute to this effect. These results suggest that overexpression of TIMPs, particularly TIMP-3 at the invasive front of pannus tissue, may provide a novel therapeutic strategy for inhibiting joint destruction in RA.
OBJECTIVE: To analyse the functional response of p53 in rheumatoid arthritis synovial fibroblasts (RASF) in vitro and in vivo and to investigate whether activation of p53 modulates the destructive process of RASF. METHODS: RASF and controls grown on chamber slides were either directly examined with DO7 anti-p53 antibodies by immunofluorescence or irradiated with 10 Gy x rays and analysed time dependently for the expression of p53. The percentage of positive cells was evaluated by a quantitative scoring system. RASF and normal (N) SF cultured in vitro were co-implanted with human cartilage in SCID mice for 60 days. Consecutively, the invasion score was evaluated, and the number of p53 positive cells was determined at the sites of invasion by immunohistochemistry. In addition, synovial tissues from RA, osteoarthritis, and normal synovia were stained with DO7 antibodies. RESULTS: In vitro the rate of expression of p53 in RASF was low (<5%), but transiently inducible by ionising irradiation (50%). In vitro low p53 expressing RASF disclosed, when invading articular cartilage, a nuclear p53 signal in 20% of the cells, indicating the induction of p53 in a distinct population of RASF during the invasive process. CONCLUSIONS: These data suggest an inductive p53 response at sites of cartilage invasion during the destructive process driven by activated RASF.
The vascular system that ensures an adequate blood flow is required to provide the cells with sufficient supply of nutrients and oxygen. Two different mechanisms of the formation of new vessels can be distinguished: vasculogenesis, the formation of the first primitive vascular plexus de novo and angiogenesis, the formation of new vessels from preexisting ones. Both processes are regulated by a delicate balance of pro- and anti-angiogenic factors. Physiologically, angiostatic mediators outweigh the angiogenic molecules and angiogenesis does not occur. Under certain conditions such as tumor formation or wound healing, the positive regulators of angiogenesis predominate and the endothelium becomes activated. Angiogenesis is initiated by vasodilatation and an increased permeability. After destabilization of the vessel wall, endothelial cells proliferate, migrate and form a tube, which is finally stabilized by pericytes and smooth muscle cells. Numerous soluble growth factors and inhibitors, cytokines and proteases as well as extracellular matrix proteins and adhesion molecules strictly control this multi-step process. The properties and interactions of angiogenic molecules such as VEGFs, FGFs, angiopoietins, PDGF, angiogenin, angiotropin, HGF, CXC chemokines with ELR motif, PECAM-1, integrins and VE-cadherin as well as angiostatic key players such as angiostatin, endostatin, thrombospondin, CXC chemokines without ELR motif, PEDF are discussed in this review with respect to their molecular impact on angiogenesis.
The objective of the study was to determine the effects and the molecular background of interleukin-1 receptor antagonist (IL-1Ra) and vIL-10 double gene transfer into human synovial fibroblasts from patients with rheumatoid arthritis (RA) using the SCID mouse model for cartilage erosion in RA. RA synovial fibroblasts were transduced with retro- or adenoviruses encoding IL-1Ra and/or viral IL-10 (vIL-10). SCID mice were engrafted subcutaneously with IL-1Ra and vIL-10 transduced human rheumatoid synovial fibroblasts and normal cartilage. In parallel, gene expression analysis before and after gene transfer using RNA arbitrarily primed PCR in combination with cDNA array was performed. vIL-10 and IL-1Ra double gene transfer resulted in inhibition of cartilage invasion and degradation by RA synovial fibroblasts when compared with control transduced and non-transduced implants. Expression of key genes that were altered after double gene transfer were related to the activin pathway. The results demonstrate not only that virus-based gene transfer using a combination of two joint-protective genes is a feasible approach to inhibit cartilage degradation by activated RA synovial fibroblasts, but also that the underlying molecular effects include modulation of the activin pathway.
OBJECTIVE: To study the pattern and cell type-specificity of collagenase 3, membrane-type 1 matrix metalloproteinase (MT1-MMP), and gelatinase A mRNA expression in the synovial membrane in rheumatoid arthritis (RA). METHODS: The mRNA expression of collagenase 3, MT1-MMP, and gelatinase A was characterised by northern blot analysis, reverse transcriptase-polymerase chain reaction, and in situ hybridisation. In situ hybridisation was performed in combination with the immunohistochemical detection of cell type-specific antigens. RESULTS: Synovial membrane specimens from 19 of 21 patients with RA expressing collagenase 3 mRNA were positive for MT1-MMP and gelatinase A mRNA. In control samples from patients without destructive inflammatory joint diseases collagenase 3 mRNA was not expressed and only in two of seven cases was a coexpression of MT1-MMP and gelatinase A mRNA detected. Fibroblast-like cells of the synovial membrane were found to be the predominant source of collagenase 3, MT1-MMP, and gelatinase A mRNA expression in lining and sublining layers as well as at the synovial membrane-cartilage interface. Additionally, the expression of MT1-MMP mRNA was detected in endothelial cells. Collagenase 3 mRNA expression was found in about 5% of CD68 positive macrophages. CONCLUSIONS: Collagenase 3 mRNA is expressed simultaneously with MT1-MMP and gelatinase A mRNA in fibroblast-like cells of the synovial membrane in RA. These results suggest (a) a broad extracellular proteolytic potential of fibroblast-like cells and (b) an important role of cell surface associated procollagenase 3 activation by MT1-MMP and gelatinase A for cartilage degradation by invading fibroblast-like cells.
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OBJECTIVE: In vitro data suggest that the tumor suppressor p53 is critically involved in the regulation of proliferation and apoptosis in fibroblast-like synoviocytes (FLS). Based on evidence that abnormalities in p53 expression and function are found in rheumatoid arthritis (RA), we analyzed whether inhibition of p53 using gene transfer with the human papilloma virus type 18 (HPV-18) E6 protein results in an increased cellularity and invasiveness of synovial fibroblasts in vivo. METHODS: RA and normal FLS were transduced with a pLXSN-based construct encoding for the HPV-18 E6 protein or with the pLXSN vector alone. After selection with G418, FLS were coimplanted with normal human cartilage under the renal capsule of SCID mice. Parental, nontransduced cells were used as additional controls. After 60 days, the implants were removed, and FLS invasion into the cartilage, perichondrocytic degradation, and cellularity were assessed. RESULTS: Nontransduced and mock-transduced RA FLS exhibited characteristic invasion into the cartilage (mean +/- SEM scores 2.2 +/- 0.3 and 2.4 +/- 0.2, respectively). Invasion was increased significantly in the E6-transduced RA FLS (mean score 3.1 +/- 0.3; P < 0.05). Inhibition of p53 also resulted in an increase in cellularity. Parental and mock-transduced normal FLS did not exhibit significant invasion (mean score 1.5 +/- 0.1 and 1.4 +/- 0.3, respectively), but transduction with E6 resulted in clear invasiveness (mean score 2.4 +/- 0.4) as well as increased cellularity. CONCLUSIONS: The data suggest that inhibition of endogenous p53 leads to increased invasiveness and cellularity of RA FLS and may also transform normal FLS to cells that display an aggressive, RA FLS-like behavior. Therefore, abnormalities such as somatic mutations in the p53 tumor suppressor may contribute to synovial hyperplasia and invasion in RA.
OBJECTIVE: Cysteine proteases are postulated to play a role in tissue destruction in the joints of animals with arthritis. The purpose of the present study was to confirm the concept that cysteine proteases are enzymes involved in the pathology of rheumatoid arthritis (RA). METHODS: Arthritis was induced in Lewis rats by adjuvant injection (adjuvant-induced arthritis [AIA] model) and scored for inflammation. At necropsy, the rear paws were either fixed in formalin and assigned a histologic score (based on synovial cell proliferation, cartilage erosion, bone erosion, and fibroproliferative pannus) or frozen, cryosectioned, and assayed for enzyme activity either by in situ cytochemical staining with a post-azo-coupling method using a chromogenic substrate (Z-arg-arg-MNA) or by a novel assay placing the tissue section directly in a cuvette using the fluorogenic substrate Z-arg-arg-AMC. RESULTS: Enzymatic activity, measured either in frozen sections in situ or in the cuvette assay, was positively correlated with joint destruction (r = 0.7) and inflammation (r = 0.8). Activity was not inhibited significantly by Pefabloc (a serine protease inhibitor), EDTA (a metalloprotease inhibitor), or pepstatin A (an aspartyl protease inhibitor) but was inhibited by E-64 and vinyl sulfone irreversible inhibitors of cysteine proteases. The effect of one of the vinyl sulfone cysteine protease inhibitors, Mu-Leu-HomoPhe-vinylsulfone, was tested in vivo by dietary administration at 2.2 mg/kg/day in the AIA model; this resulted in a significant decrease in inflammation and in the amount of cysteine protease activity measured in the joint tissue. CONCLUSION: Cysteine protease activity levels increase in the diseased state and may be an important target for designing small molecule inhibitors to reduce the inflammation and tissue destruction associated with RA.