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Abstract

Background La/SSB is a phosphoprotein that associates with various small RNA molecules. It has been found that the primary phosphorylation site of the molecule during various physiological processes is in Ser366. Objectives To determine whether the phosphorylation state of Ser366 could affect the antigenicity and the recognition of the protein by antibodies from patients with primary Sjögren's syndrome (pSS). Methods Peptides 349-368aa and phos349-368aa (with the Ser366 residue phosphorylated) were synthesized. Sera with anti-La specificity from 30 patients with pSS and sera from 19 normal individuals were examined against the two synthetic peptides in ELISA. The antibody specificity against the epitopes was tested with homologous and heterologous inhibition assays. Results Of pSS sera 23% reacted against the 349-368aa peptide. Sera binding to unphosphorylated peptide reacted also with phos349-368aa. Although the same sera gave a positive reaction against both peptides, the optical density values received from antibodies to phos349-368aa were higher, indicating a higher concentration or stronger affinity. When phos349-368aa was used as soluble inhibitor, in homologous inhibition the reactivity was almost completely abolished (92%). In contrast, when the unphosphorylated peptide was used as inhibitor, the reactivity of sera against phos349-368aa was only partially reduced (35%), indicating that sera from these patients possess two distinct groups of antibodies: one against the unphosphorylated and one against the phosphorylated epitope. Conclusion The phosphorylation of the serine366 residue resulted in a significant increase in antibody binding on epitope 349-368aa of La/SSB. These observations might explain the increased antigenicity of La/SSB autoantigen in various pathological situations in which phosphorylation may occur. 2 Surface-bound immune complexes containing antibodies to collagen type II induce production of TNF-α α, IL-1β β and IL-8 from monocytes via Fcγ γRII

Gene Expression Profiling of Rheumatoid Arthritis Synovial Cells Treated with Antirheumatic Drugs

“…Isolated and propagated RASF show enhanced, tumor-like proliferation activity, 19 have the capacity to invade cartilage in an severe combined immunodeficient (SCID) mouse model, 20 and may reflect the disease status of the synovial tissue from which they originated. 21 In this work, we took advantage of these growth properties of RASF and their pathophysiological relevance. To ensure standardization and comparability between different drugtesting experiments, we used immortalized synovial fibroblasts and determined the RA gene expression profiles that are reverted by the treatment with commonly used antirheumatic drugs.…”

Light‐Triggered Drug Release from Red Blood Cells Suppresses Arthritic Inflammation

“…These experiments were recapitulated using primary FLS cells from RA patients. We do note that FLS cells are phenotypically heterogeneous [32] and do not display the near 100% uniform GR𝛼 nuclear migration observed with HeLa cells. However, both 660 nm exposed hRBCs bearing 1, and Dex itself, trigger the same degree of GR𝛼 relocation in FLS cells (Figure 4B; Figures S17 and S18, Supporting Information).…”

Emerging Landscape of In Vitro Models for Assessing Rheumatoid Arthritis Management

“…To understand the healthy condition of the synovium, an ideal kind of cell mimicking the FLSs, which is widely available and easy to culture, is a need of the hour and can simulate the synovial tissue in in vitro experiments, as a major limitation of the FLSs models is their dependence for diseased FLSs which is not widely available and is also affected by the drugs and the stages of the illness. 105 The adult MSCs show almost similar properties as FLSs, such as differentiation, the ability to generate hyaluronic acid, and surface markers; they can be considered promising cells in the 3D culture to study the synovial membrane in vitro. 106 Overall, the studies have indicated that both well-known signaling molecules, such as recombinant cytokines, which contain inflammatory components, serve as mediators of communication between different joint cells and tissues, and have a significant impact on the development of RA.…”