Ameliorated Autoimmune Arthritis and Impaired B Cell Receptor-Mediated Ca2+ Influx in Nkx2-3 Knock-out Mice

Abstract

B cells play a crucial role in the pathogenesis of rheumatoid arthritis. In Nkx2-3-deficient mice (Nkx2-3−/−) the spleen’s histological structure is fundamentally changed; therefore, B cell homeostasis is seriously disturbed. Based on this, we were curious, whether autoimmune arthritis could be induced in Nkx2-3−/− mice and how B cell activation and function were affected. We induced arthritis with immunization of recombinant human proteoglycan aggrecan G1 domain in Nkx2-3−/− and control BALB/c mice. We followed the clinical picture, characterized the radiological changes, the immune response, and intracellular Ca2+ signaling of B cells. Incidence of the autoimmune arthritis was lower, and the disease severity was milder in Nkx2-3−/− mice than in control BALB/c mice. The radiological changes were in line with the clinical picture. In Nkx2-3−/− mice, we measured decreased antigen-induced proliferation and cytokine production in spleen cell cultures; in the sera, we found less anti-CCP-IgG2a, IL-17 and IFNγ, but more IL-1β, IL-4 and IL-6. B cells isolated from the lymph nodes of Nkx2-3−/− mice showed decreased intracellular Ca2+ signaling compared to those isolated from BALB/c mice. Our findings show that the transcription factor Nkx2-3 might regulate the development of autoimmune arthritis most likely through modifying B cell activation.

Presence of TRPA1 Modifies CD4+/CD8+ T Lymphocyte Ratio and Activation

“…No. F-1242) according to the protocol described earlier [105][106][107]. Briefly, cells isolated and homogenized mechanically from the spleen or thymus were suspended in RPMI supplemented with 5% FBS, containing 2 mM CaCl 2 (CaRPMI).…”

“…No. F-1242) in a CO 2 incubator for 30 min at 37 • C. Cell suspension was diluted in RPMI supplemented with 5% FBS and 2 mM CaCl 2 (CaRPMI) [105], incubated for an additional 20 min, washed in CaRPMI and immediately measured in a Becton Dickinson FacsCalibur flow cytometer. Mean fluorescence intensity of Fluo-3 dye (FL1) was monitored in CD4+ or CD8+ subpopulations before and after stimulation with anti-mouse CD3 and crosslinking with anti-hamster IgG as described earlier [99,101] for 10 min.…”

Splenectomy modulates the immune response but does not prevent joint inflammation in a mouse model of RA

“…The translational significance of the GIA arthritis model lies in its ability to mimic many clinical and immunological aspects of human RA [ 22 , 24 , 25 ]. In the GIA mouse, model there is a predominant Th1 and Th17 polarization during arthritis induction, which is accompanied by significant autoantibody production including anti-rhG1- and anti-cyclic citrullinated peptide antibodies (anti-CCP) [ 24 , 26 , 27 ].…”

“…In our previous study, we investigated the effect of the Nkx2-3 transcription factor (TF) genetic deficiency in autoimmune arthritis [ 26 ]. Nkx2-3 is a homeodomain TF which is crucial for the development of the spleen, and the expression and regulation of mucosal addressin cell adhesion molecule-1 (MADCAM-1) [ 28 , 29 ].…”

Research of Pathogenesis and Novel Therapeutics in Arthritis 2.0

“…(ii) New biomarkers. Khanfar and colleagues describe preclinical findings showing that the transcription factor Nkx2-3 appears to regulate the development of autoimmune arthritis, probably via B cell signaling [9]. Li and Zheng have identified novel targets of knee OA shared by synovium and cartilage, which may help with the development of novel OA therapies [10].…”