Rheumatoid Arthritis: Carson DA

Silverman GJ, Carson DA. · Rheumatic Disease Core Center and Division of Rheumatology, Allergy and Immunology, Department of Medicine, University of California San Diego, La Jolla, California, USA. · Arthritis Res Ther. · Pubmed #15180890 No free full text.

Abstract: B lymphocytes play several critical roles in the pathogenesis of rheumatoid arthritis. They are the source of the rheumatoid factors and anticitrullinated protein antibodies, which contribute to immune complex formation and complement activation in the joints. B cells are also very efficient antigen-presenting cells, and can contribute to T cell activation through expression of costimulatory molecules. B cells both respond to and produce the chemokines and cytokines that promote leukocyte infiltration into the joints, formation of ectopic lymphoid structures, angiogenesis, and synovial hyperplasia. The success of B cell depletion therapy in rheumatoid arthritis may depend on disruption of all these diverse functions.

Prakken BJ, Carson DA, Albani S. · Department of Pediatrics, University of California San Diego, La Jolla, Calif., USA. · Curr Dir Autoimmun. · Pubmed #11791471 No free full text.

This publication has no abstract.

Ohata J, Zvaifler NJ, Nishio M, Boyle DL, Kalled SL, Carson DA, Kipps TJ. · Division of Hematology/Oncology, University of California, San Diego, La Jolla 92093, USA. · J Immunol. · Pubmed #15634908 links to  free full text

Abstract: Immunohistochemical analysis revealed that the intimal lining cells of synovial tissue of inflamed joints of patients with rheumatoid arthritis differed from that of normal joints or of diseased joints in osteoarthritis in that they stained with mAb specific for the B cell-activating factor of the TNF family (BAFF; also called BLyS). We generated fibroblast-like synoviocytes (FLS) cell lines that were bereft of myelomonocytic cells to examine whether mesenchymal-derived FLS could express this critical B cell survival factor. We found that FLS expressed low amounts of BAFF mRNA relative to that of myelomonocytic cells. However, when various cytokines/factors were added to such FLS cell lines, we found that IFN-gamma or TNF-alpha were unique in that they could induce significant increases in BAFF mRNA and protein. Even minute amounts of IFN-gamma primed FLS for TNF-alpha, allowing the latter to stimulate significantly higher levels of BAFF mRNA and protein than could TNF-alpha alone. Consistent with this, B cells cocultured with IFN-gamma and/or TNF-alpha-treated FLS had a significantly greater viability than B cells cocultured with nontreated FLS. The enhanced protection of B cells afforded by IFN-gamma/TNF-alpha-treated FLS was inhibited by the addition of BAFF-R:Fc fusion protein. We conclude that the proinflammatory cytokines IFN-gamma and TNF-alpha can induce mesenchymal-derived FLS to express functional BAFF in vitro. The induced expression of BAFF on FLS by proinflammatory cytokines may enhance the capacity of such cells to protect B cells from apoptosis in inflammatory microenvironments in vivo.

Kyburz D, Rethage J, Seibl R, Lauener R, Gay RE, Carson DA, Gay S. · Center of Experimental Rheumatology and Department of Rheumatolgy, University Hospital of Zurich, Zurich, Switzerland. · Arthritis Rheum. · Pubmed #12632416 links to  free full text

Abstract: OBJECTIVE: To test the hypothesis that bacterial products acting as adjuvants, such as CpG oligodeoxynucleotides (ODNs) and peptidoglycans (PGs), are able to activate synoviocytes, and to determine the involvement of Toll-like receptors (TLRs) in this activation process. METHODS: Cultured synovial fibroblasts obtained from patients with rheumatoid arthritis (RA) or osteoarthritis (OA) were stimulated with CpG ODNs or PGs. The expression of various integrins was determined by fluorescence-activated cell sorting. TLR and matrix metalloproteinase (MMP) messenger RNA (mRNA) was measured by real-time polymerase chain reaction. Additionally, levels of interleukin-6 (IL-6) and IL-8 in the culture supernatants were assessed by enzyme-linked immunosorbent assay. Blocking experiments were performed by adding anti-TLR-2 and anti-TLR-4 monoclonal antibodies to cultures stimulated with bacterial PGs. RESULTS: Incubation of synovial fibroblasts with CpG ODNs resulted in neither up-regulation of the expression of integrins on the cell surface, up-regulation of MMP mRNA expression, nor IL-6 and IL-8 production. However, incubation of RA synovial fibroblasts as well as OA synovial fibroblasts with staphylococcal PGs led to an up-regulation of CD54 (ICAM-1) surface expression and to increased expression of MMP-1, MMP-3, and MMP-13 mRNA. Furthermore, production of the proinflammatory cytokines IL-6 and IL-8 was increased by treatment with PGs. We demonstrated that cultured synovial fibroblasts express low levels of TLR-2 and TLR-9 mRNA. TLR-2 was up-regulated after stimulation with PGs, whereas TLR-9 mRNA remained at baseline levels after stimulation with CpG ODNs. Anti-TLR-2 monoclonal antibodies significantly inhibited production of IL-6 and IL-8 induced by stimulation with PGs. CONCLUSION: We demonstrate that bacterial PGs activate synovial fibroblasts, at least partially via TLR-2, to express integrins, MMPs, and proinflammatory cytokines. Inhibition of TLR signaling pathways might therefore have a beneficial effect on both joint inflammation and joint destruction.

Sen M, Reifert J, Lauterbach K, Wolf V, Rubin JS, Corr M, Carson DA. · Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0663, USA. · Arthritis Rheum. · Pubmed #12428226 links to  free full text

Abstract: OBJECTIVE: The enhanced release of extracellular matrix proteins by fibroblast-like synoviocytes (FLS) from rheumatoid arthritis (RA) patients is suggestive of joint remodeling. Because Wnt proteins play a critical role in joint development, we investigated whether up-regulated Wnt signaling plays a role in the enhanced synthesis of extracellular matrix proteins. The purpose of the present experiments was to determine the role of Wnt-1-like molecules in the expression of matrix proteins by RA FLS and to ascertain the effects of Wnt antagonists on RA FLS function and survival. METHODS: Transfection with a reporter plasmid (TOPflash) was performed to assess whether Wnt signaling is active in RA FLS. Wnt signaling was up-regulated in normal FLS by transfection with a Wnt-1 expression plasmid and was down-regulated in RA FLS by transfection with dominant-negative lymphoid enhancer factor 1 (LEF-1)/T cell factor 4 (TCF-4) and secreted Frizzled receptor protein 1 (sFRP-1) expression plasmids. Recombinant sFRP-1 and anti-Wnt-1 antibody were also administered to RA FLS to block Wnt signaling. RESULTS: RA FLS had constitutive activation of the canonical Wnt signaling pathway. Transfection of normal FLS with a Wnt-1 expression vector enhanced not only fibronectin, but also pro-matrix metalloproteinase 3 (proMMP-3) expression. In a complementary manner, interference with Wnt signaling using anti-Wnt-1 antibody, the Wnt antagonist sFRP-1, or dominant-negative vectors that inhibited the transcription factors TCF-4/LEF-1 blocked the expression of fibronectin by RA FLS and reduced cell survival. Anti-Wnt-1 antibody and sFRP-1 also blocked the expression of proMMP-3. CONCLUSION: Our results indicate that the canonical Wnt pathway regulates fibronectin and metalloproteinase expression in RA FLS.

Sen M, Chamorro M, Reifert J, Corr M, Carson DA. · Department of Medicine, University of California, San Diego, La Jolla 92093-0663, USA. · Arthritis Rheum. · Pubmed #11315916 links to  free full text

Abstract: OBJECTIVE: It is not understood why cultured fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) often display a persistently activated phenotype, despite removal from an inflammatory environment. Previously, we found that these FLS expressed high levels of both Wnt-5A and Frizzled 5 (Fz5), a receptor-ligand pair implicated in both limb bud and bone marrow stem cell development. The objective of the present experiments was to determine whether Wnt-5A/FzS signaling contributes to FLS activation. METHODS: Wnt-5A expression in FLS was inhibited by transfection with both antisense and dominant negative (dn) vectors. Fz5 signaling was blocked with an antibody to the extracellular domain of the receptor. The effects of these treatments on the expression of the proinflammatory cytokines interleukin-6 (IL-6) and IL-15 and on the expression of receptor activator of nuclear factor kappaB ligand (RANKL) were assessed by reverse transcriptase-polymerase chain reaction and immunoblotting. RESULTS: Both antisense Wnt-5A and dnWnt-5A vectors, but not empty vector, diminished IL-6 and IL-15 expression in RA FLS. Anti-Fz5 antibody exerted similar effects and also reduced RANKL expression. CONCLUSION: Wnt-5A/Fz5 signaling may contribute to the activated state of FLS in RA. Receptor antagonists of Fz5 should be considered for the treatment of refractory synovitis.

Kyburz D, Carson DA, Corr M. · University of California, San Diego, La Jolla 92093-0663, USA. · Arthritis Rheum. · Pubmed #11083282 links to  free full text

Abstract: OBJECTIVE: Spontaneous arthritis in the KRN transgenic mouse (K/BxN) model is due to the autoreactivity of the transgenic T cell receptor and subsequent induction of autoantibodies directed against glucose-6-phosphate isomerase (G6PI). This study sought to analyze the potential of anti-CD40 ligand (anti-CD40L) and anti-tumor necrosis factor alpha (anti-TNFalpha) antibodies in preventing and treating arthritis in this murine model. METHODS: Groups of K/BxN mice were injected with anti-CD40L and anti-TNFalpha antibodies during various stages of arthritis. Disease was assessed by clinical scoring, measurements of paw swelling, and histology. The results were correlated with the levels of autoantibodies in the serum, as assessed by enzyme-linked immunosorbent assay. RESULTS: Anti-CD40L antibody treatment was able to diminish significantly the arthritis development in K/BxN mice when given a week before the onset of clinically apparent disease. However, no effect on disease was seen when the antibodies were administered after clinical onset. Surprisingly, neutralizing anti-TNFalpha antibodies were unable to prevent arthritis in K/BxN mice. The success of antibody treatment in preventing disease correlated with low levels of anti-G6PI antibodies in the serum. CONCLUSION: These results suggest that anti-CD40L treatment can prevent arthritis development in a model of immunoglobulin-mediated arthritis, but anti-TNFalpha treatment cannot. The unsuccessful treatment of established disease was possibly due to the continued presence of autoreactive antibodies in the arthritic mice.

Sen M, Lauterbach K, El-Gabalawy H, Firestein GS, Corr M, Carson DA. · Department of Medicine and the Sam and Rose Stein Institute for Research on Aging, University of California, San Diego, La Jolla, CA 92093-0663, USA. · Proc Natl Acad Sci U S A. · Pubmed #10688908 links to  free full text

Abstract: Rheumatoid arthritis (RA) is accompanied by synovial inflammation, proliferation, and cartilage destruction. The reasons the activation of synovial fibroblasts often persists despite antiinflammatory therapy are not known. One possibility is that the synovial membrane becomes gradually repopulated with immature mesenchymal and bone marrow cells with altered properties. To explore this hypothesis, we have investigated the expression in RA synovial tissues of various embryonic growth factors from the wingless (wnt) and frizzled (fz) families, which have been implicated in cell-fate determination in both bone marrow progenitors and limb-bud mesenchyme. Reverse transcriptase-PCR analysis revealed expression of five wnt (wnt1, 5a, 10b, 11, and 13) and three fz (fz2, 5, and 7) isoforms in RA synovial tissues. Osteoarthritis synovial tissues expressed much less wnt5a and fz5. Northern blotting confirmed the overexpression of wnt5a and fz5 in RA synovial tissues, in comparison to a panel of normal adult tissues. Compared with normal synovial fibroblasts, cultured RA fibroblast-like synoviocytes expressed higher levels of IL-6, IL-8, and IL-15. Transfection of normal fibroblasts with a wnt5a expression vector reproduced this pattern of cytokine expression and stimulated IL-15 secretion. These results suggest that the unusual phenotypic properties of RA fibroblasts may be attributable partly to their replacement with primitive fibroblast-like synoviocytes with characteristics of immature bone marrow and mesenchymal cells. Clear delineation of the signaling pathway(s) initiated by the wnt5a/fz5 ligand-receptor pair in the RA synovium may yield new targets for therapeutic intervention.

Kyburz D, Corr M, Brinson DC, Von Damm A, Tighe H, Carson DA. · Department of Medicine, The Sam and Rose Stein Institute for Research on Aging, University of California at San Diego, La Jolla 92093, USA. · J Immunol. · Pubmed #10477577 links to  free full text

Abstract: High-affinity pathologic rheumatoid factor (RF) B cells occur in autoimmune diseases such as rheumatoid arthritis, but are deleted in healthy individuals. The reasons for the survival and differentiation of these autoreactive B cells in rheumatoid arthritis are not known. Previous studies in mice transgenic for a human IgM RF have shown that peripheral encounter with soluble human IgG leads to deletion of high-affinity RF B cells; however, deletion can be prevented when concomitant T cell help is provided. This study aimed to further discern the minimal factors necessary not only for the in vivo survival of RF B cells, but also for their differentiation into Ab-secreting cells. The combination of MHC class II-reactive T cells and Ag induced the production of RF in human IgM RF transgenic mice, while either stimulus alone was ineffective. Neutralizing Abs against CD40 ligand (CD40L), but not against IL-4 or IL-15, abrogated IgM-RF production. Moreover, blockade of CD40L-CD40 allowed IgG to delete the RF precursor cells. Most importantly, activating Abs to CD40 could substitute entirely for T cell help in promoting the survival of RF precursors and in stimulating RF synthesis in T cell deficient animals. The data indicate that CD40 signaling alone can prevent deletion of RF B cells by Ag and in the presence of IgG is sufficient to trigger RF synthesis. The results suggest that selective induction of apoptosis in high-affinity RF B cells may be achieved by blockade of CD40L-CD40 interaction.

Chukwuocha RU, Zhang B, Lai CJ, Scavulli JF, Albani S, Carson DA, Chen PP. · Department of Medicine, University of California, Los Angeles 90095-1670, USA. · J Rheumatol. · Pubmed #10405927 No free full text.

Abstract: OBJECTIVE: Previously, we showed that rheumatoid arthritis (RA) had both antibodies and T cells specific for the QKRAA-encompassing Escherichia coli dnaJ protein. These findings suggest that the bacteria induced anti-dnaJ responses may cross react with the human homolog of bacterial dnaJ in the joint, resulting in tissue damage. METHODS: We used the combinatorial library technique to isolate and characterize an IgG monoclonal anti-dnaJ antibody (designated CG1) from the blood of a patient with RA. RESULTS: Sequence analysis of CG1 revealed that its heavy and light chain V regions were respectively most homologous to the 3d279d VH4 and the O18 Vk1 genes. Interestingly, 3d279d is frequently expressed by B cells stimulated with staphylococcal enterotoxin; and O18 is the main gene employed by the Vk1 IgG antibodies against Haemophilus influenzae. CONCLUSION: The combinatorial immunoglobulin library method represents an interesting model of how to approach the isolation and characterization of antibody-like reagents in the elucidation of autoantigens in RA.

Warnatz K, Kyburz D, Brinson DC, Lee DJ, Von Damm A, Engelhart M, Corr M, Carson DA, Tighe H. · Department of Medicine and The Sam and Rose Stein Institute for Research on Aging, University of California at San Diego, La Jolla, California, 92093-0663, USA. · Cell Immunol. · Pubmed #9918688 No free full text.

Abstract: Normal individuals do not express the high-affinity autoantibodies specific for self-IgG (rheumatoid factors, RF) that are commonly seen in rheumatoid arthritis patients. Studies of transgenic mice expressing a human IgM rheumatoid factor have shown that one mechanism by which higher affinity RF B cells are tolerized to IgG is through abortive RF B cell activation followed by deletion in the absence of T cell help. We show that RF B cell deletion occurs through an intrinsic apoptotic mechanism that is independent of the Fas/FasL pathway and does not involve active killing by T cells, as it occurs in RAG-1-deficient RF transgenic mice to the same extent as in the parental RF transgenic line.

Carson DA, Haneji N. · No affiliation provided · Nat Med. · Pubmed #10395310 No free full text.

This publication has no abstract.