Toll-like receptors expressed by synovial fibroblasts perpetuate Th1 and th17 cell responses in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial fibroblast hyperplasia and bone and cartilage erosion. Synovial fibroblast- and T cell-mediated inflammation plays crucial roles in the pathogenesis of RA. However how this inflammation is initiated, propagated, and maintained remains controversial. Here, we systemically examined the contribution of toll-like receptors (TLRs) to the inflammatory mediator production as well as Th1 and Th17 cell hyperactivity in RA. Our results show that rheumatoid arthritis synovial fibroblasts (RASF) express a series of TLRs, including TLR2, TLR3, TLR4, and TLR9, with the predominant expression of TLR3. Moreover, the expression levels of these TLRs were higher than those in osteoarthritis synovial fibroblasts (OASF). Ligation of TLR3, as well as TLR2 and TLR4, resulted in vigorous production of inflammatory cytokines, matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF) in RASF, with activation of the NF-κB, MAPK, and IRF3 pathways. More important, activation of these TLRs expressed by RASF exacerbated inflammatory Th1 and Th17 cell expansion both in cell-cell contact-dependent and inflammatory cytokine-dependent manners, which induced more IFN-γ and IL-17 accumulation. Targeting TLRs may modulate the inflammation in RA and provide new therapeutic strategies for overcoming this persistent disease

Soluble CD24 is an inflammatory biomarker in early and seronegative rheumatoid arthritis

AbstractIntroduction: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease characterized by autoantibody production, joint inflammation and bone destruction. Nearly 1/3 of RA patients with the active disease also exhibit a normal range of ESR and CRP. Here we assessed the performance and clinical significance of soluble CD24 (sCD24) as a biomarker of disease activity in RA.Methods: A total of 269 RA patients, 59 primary Sjogren’s syndrome (SS) patients, 81 systematic lupus erythematosus (SLE) patients, 76 osteoarthritis (OA) patients and 97 healthy individuals (HC) were included in this study. Soluble CD24 in sera were detected by ELISA. Therefore, the concentration of sCD24 was analyzed in RA patients with different disease activity statuses.Results: The sCD24 was significantly increased in RA (2970 pg/mL), compared to other rheumatic diseases (380-520 pg/mL) and healthy individuals (320 pg/mL). Moreover, sCD24 was elevated in 66.67% of early RA and 61.11% of seronegative RA patients. In addition, sCD24 was significantly correlated with the disease duration and inflammatory indicators.Conclusion: The sCD24 could be an inflammatory biomarker in RA patients, especially in early and seronegative patients

Spontaneous Production of Immunoglobulin M in Human Epithelial Cancer Cells

<div><p>It is well known that B-1 B cells are the main cell type that is responsible for the production of natural immunoglobulin M (IgM) and can respond to infection by increasing IgM secretion. However, we unexpectedly found that some epithelial cells also can express rearranged IgM transcript that has natural IgM characteristics, such as germline-encoded and restricted rearrangement patterns. Here we studied IgM expression in human non-B cells and found that IgM was frequently expressed by many human epithelial cancer cells as well as non-cancer epithelial cells. Moreover, CD79A and CD79B, two molecules that are physically linked to membranous IgM on the surface of B cells to form the B cell antigen receptor complex, were also expressed on the cell surface of epithelial cancer cells and co-located with IgM. Like the natural IgM, the epithelial cancer cell-derived IgM recognized a series of microbial antigens, such as single-stranded DNA, double-stranded DNA, lipopolysaccharide, and the HEp-2 cell antigen. More important, stimulation of the toll-like receptor 9 (TLR9), which mimics bacterial infection, substantially increased the secretion of IgM in human epithelial cancer cells. These findings indicate that human epithelial cancer cells as well as non-cancer epithelial cells can spontaneously produce IgM with natural antibody activity.</p> </div

A citrullinated antigenic vaccine in treatment of autoimmune arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease triggered by antigenic peptides with environmental and genetic risk factors. It has been shown that antigen-specific targeting could be a promising therapeutical strategy for RA by restoring immune tolerance to self-antigens without compromising normal immunity. Citrullination of antigens enhances antigenic properties and induces autoimmune responses. Here, we showed that citrullinated antigenic (citAg) vaccine ameliorated collagen-induced arthritis (CIA) with decreased T-helper 1 (Th1) and Th17 cells, downregulated proinflammatory cytokines including interlukin-6 and tumor necrosis factor-&alpha;, and inhibited antigen recall responses. B cell receptor (BCR) sequencing further revealed that citAg vaccine could dampen the dysregulated V(D)J recombination, restoring the immune repertoire. Taken together, the results demonstrated that citAg vaccine might have a therapeutic effect on RA.</p

A citrullinated antigenic vaccine in treatment of autoimmune arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease triggered by antigenic peptides with environmental and genetic risk factors. It has been shown that antigen-specific targeting could be a promising therapeutical strategy for RA by restoring immune tolerance to self-antigens without compromising normal immunity. Citrullination of antigens enhances antigenic properties and induces autoimmune responses. Here, we showed that citrullinated antigenic (citAg) vaccine ameliorated collagen-induced arthritis with decreased T-helper 1 (Th1) and Th17 cells, downregulated proinflammatory cytokines including interlukin-6 and tumor necrosis factor-alpha, and inhibited antigen recall responses. B cell receptor sequencing further revealed that citAg vaccine could dampen the dysregulated V(D)J recombination, restoring the immune repertoire. Taken together, the results demonstrated that citAg vaccine might have a therapeutic effect on RA. (c) 2024 Science China Press. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Soluble CD24 is an inflammatory biomarker in early and seronegative rheumatoid arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease characterized by autoantibody production, joint inflammation and bone destruction. Nearly 1/3 of RA patients with the active disease also exhibit a normal range of ESR and CRP. Here we assessed the performance and clinical significance of soluble CD24 (sCD24) as a biomarker of disease activity in RA. Methods: A total of 269 RA patients, 59 primary Sjogren’s syndrome (SS) patients, 81 systematic lupus erythematosus (SLE) patients, 76 osteoarthritis (OA) patients and 97 healthy individuals (HC) were included in this study. Soluble CD24 in sera were detected by ELISA. Therefore, the concentration of sCD24 was analyzed in RA patients with different disease activity statuses. Results: The sCD24 was significantly increased in RA (2970 pg/mL), compared to other rheumatic diseases (380-520 pg/mL) and healthy individuals (320 pg/mL). Moreover, sCD24 was elevated in 66.67% of early RA and 61.11% of seronegative RA patients. In addition, sCD24 was significantly correlated with the disease duration and inflammatory indicators. Conclusion: The sCD24 could be an inflammatory biomarker in RA patients, especially in early and seronegative patients.</p

TLR9 agonists stimulated human epithelial cancer cells to secrete IgM.

<p>A, Ig µ mRNA level was analyzed by semiquantitative RT-PCR after stimulation by CpG 2006, and the two non-CpG ODN controls, CpG 2078 and GpC. CpG-N ODN208, as negative control; GAPDH, internal control. B, flow cytometry analysis showed that cytoplasmic IgM was decreased after stimulation with CpG 2006, CpG 2078, and GpC. CpG-N ODN208, as negative control. **<i>P</i><0.01 <i>vs.</i> vehicle control. C, Western blot analysis showed that cytoplasmic IgM was decreased after stimulation with CpG 2006, CpG 2078, and GpC. CpG-N ODN208, as negative control; β-actin, internal control. D, Western blot analysis showed increased level of secreted IgM after stimulation with CpG 2006, CpG 2078, and GpC. CpG-N ODN208, as negative control. E, phosphorylation of ERK, a molecule downstream of TLR9 signaling cascade, was detected by Western blot after stimulation with CpG 2006, CpG 2078, and GpC. EGF, epidermal growth factor was used as a positive control for ERK phosphorylation. F, Western blot analysis showed that IκB, a molecule in NF-κB pathway, also was phosphorylated after stimulation with CpG 2006, CpG, 2078 and GpC.</p

Detection of IgM expression by immunohistochemistry on tissue microarray.

<p>A, lung cancer cells; B, breast cancer cells; C, liver cancer cells; D, pancreatic cancer cells; E, renal tubule epithelial cells; F, endometrium epithelial cells; G, renal tubule epithelial cells, stained with goat anti-mouse IgG-HRP only, as a negative control; H, endometrium epithelial cells, stained with goat anti-mouse IgG-HRP only, as a negative control; I, leiomyoma cells; J, T lymphoma cells; K, seminoma cells; L, spermatocytes.</p

Human epithelial cancer cell-derived IgM recognized various self and non-self antigens.

<p>A–C, ELISA showed that secreted IgM in culture supernatant of HeLa MR cells could recognize ssDNA (A), dsDNA (B), and LPS (C). D, indirect immunofluorescence analysis showed that secreted IgM in culture supernatant of HeLa MR cells could recognize autoantigens in HEp-2 cells.</p