Galectin 3 induces a distinctive pattern of cytokine and chemokine production in rheumatoid synovial fibroblasts via selective signaling pathways

Abstract

Objective. High expression of galectin 3 at sites of joint destruction in rheumatoid arthritis (RA) suggests that galectin 3 plays a role in RA pathogenesis. Previous studies have demonstrated the effects of galectins on immune cells, such as lymphocytes and macrophages. This study was undertaken to investigate the hypothesis that galectin 3 induces proinflammatory effects in RA by modulating the pattern of cytokine and chemokine production in synovial fibroblasts.Methods. Matched samples of RA synovial and skin fibroblasts were pretreated with galectin 3 or tumor necrosis factor ␣ (TNF␣), and the levels of a panel of cytokines, chemokines, and matrix metalloproteinases (MMPs) were determined using enzyme-linked immunosorbent assays and multiplex assays. Specific inhibitors were used to dissect signaling pathways, which were confirmed by Western blotting and NF-B activation assay.Results. Galectin 3 induced secretion of interleukin-6 (IL-6), granulocyte-macrophage colonystimulating factor, CXCL8, and MMP-3 in both synovial and skin fibroblasts. By contrast, galectin 3-induced secretion of TNF␣, CCL2, CCL3, and CCL5 was significantly greater in synovial fibroblasts than in skin fibroblasts. TNF␣ blockade ruled out autocrine TNF␣-stimulated induction of chemokines. The MAPKs p38, JNK, and ERK were necessary for IL-6 production, but phosphatidylinositol 3-kinase (PI 3-kinase) was required for selective CCL5 induction. NF-B activation was required for production of both IL-6 and CCL5.Conclusion. Our findings indicate that galectin 3 promotes proinflammatory cytokine secretion by tissue fibroblasts. However, galectin 3 induces the production of mononuclear cell-recruiting chemokines uniquely from synovial fibroblasts, but not matched skin fibroblasts, via a PI 3-kinase signaling pathway. These data provide further evidence of the role of synovial fibroblasts in regulating the pattern and persistence of the inflammatory infiltrate in RA and suggest a new and important functional consequence of the observed high expression of galectin 3 in the rheumatoid synovium.

Activation of human fibroblast-like synoviocytes by uric acid crystals in rheumatoid arthritis

“…47 Moreover, the JNK and ERK signaling pathways are involved in pro-inflammatory cytokine and chemokine production in activated FLS. 48,49 Numerous studies have demonstrated that the inhibition of the JNK and ERK pathways has profound effects on the synthesis of inflammatory cytokines and modulation of acute and chronic inflammation. 50 …”

The role of galectin-3 and galectin-3–binding protein in venous thrombosis

“…34 Several studies have shown that gal3 upregulates IL-6 in pathologic conditions. 7,8,35 We have previously shown that IL-6 plays a key role in promoting VT. 15 We therefore decided to investigate the relationship between gal3 and IL-6 during VT. The strong correlation we observed between gal3 and IL-6 expression in the vein wall led us to examine whether these were mechanistically involved in venous thrombogenesis.…”

“…[5][6][7][8] Both gal3bp and gal3 are found in most normal adult tissues, mainly in epithelial and myeloid/amoeboid cells, 9 but to our knowledge they have never been previously explored in platelets (PLTs), red blood cells (RBCs), microparticles, vein walls, and venous thrombus, all critical elements that participate in VT. Gal3 is found within the nucleus, cytoplasm, cell surface, and extracellular space as a monomer, or multimer, or it is fragmented as a result of enzymatic cleavage. 10 Gal3 multimerization is known to have physiologic consequences, such as enhancing the ability of gal3 to facilitate cell-to-cell interactions.…”

“…11,12 Gal3bp and gal3, in both its monomeric and multimeric forms, are thought to play pathologic roles in a number of diseases such as cancer and rheumatoid arthritis. 7,8,13,14 In cancer, gal3bp and both gal3 monomers and multimers contribute to metastasis by promoting cell-cell adhesion. 7,9,13 Exogenous gal3, administered IV to mice or directly to cultured cells in doses intended to mimic the amount of circulating gal3 observed in patients with inflammatory diseases (1-10 mg/mL), induces the secretion of interleukin-6 (IL-6), CCL2, the mouse version of human MCP1, and tumor necrosis factor (TNF)-a.…”

Intra-articular lentivirus-mediated delivery of galectin-3 shRNA and galectin-1 gene ameliorates collagen-induced arthritis

“…14,15 Recently, galectin-1 was shown to induce the production of interleukin-10 and attenuate the secretion of interferon-g in activated T cells, and galectin-3 was shown to promote the production of proinflammatory cytokines, such as interleukin-6 and tumor necrosis factor-a, in synovial fibroblasts. 16,17 A single injection of syngenic DBA/1 fibroblasts engineered to secret galectin-1 at the onset of disease abrogated experimental arthritis in mice. 18 Furthermore, microarray analysis of peripheral mononuclear cells has identified galectin-3 as a blood biomarker in the rat CIA model.…”