Inhibition of the TIM-1 and -3 signaling pathway ameliorates disease in a murine model of rheumatoid arthritis.

Members of the T-cell immunoglobulin and mucin (TIM) family, which is crucial for T-cell function, are implicated in autoimmunity. TIM-1 and -3 play distinct roles in autoimmunity, with TIM-1 acting as a costimulatory molecule and TIM-3 regulating Th1 responses. We investigated the therapeutic potential of anti-TIM-1 (RMT1-10) and anti-TIM-3 (RMT3-23) antibodies in an autoimmune arthritis model. Zymosan A was used to induce arthritis in female SKG mice. The arthritis scores, histology, mRNA expression, cytokine levels, micro-computed tomography, and flow cytometry results were obtained. The application of RMT1-10 reduced the arthritis scores, histological damage, and CD4+ T-cell infiltrations, and it suppressed interleukin (IL)-6 and -17A and reduced TIM-3 mRNA expressions. RMT3-23 also lowered arthritis severity, improved histology, and reduced serum levels of tumor necrosis factor (TNF)-α and IL-17A. RMT3-23 inhibited intracellular TNF-α and IL-6 and early apoptosis. An amelioration of autoimmune arthritis was achieved by blocking the TIM-1 and -3 signaling pathways via RMT1-10 and RMT3-23 administration, leading to a widespread decrease in inflammatory cytokines. Both antibodies exhibited therapeutic effects, suggesting TIM-1 and -3 as potential targets for rheumatoid arthritis.

Blockade of IL-18Rα-mediated signaling pathway exacerbates neutrophil infiltration in imiquimod-induced psoriasis murine model.

Psoriasis is an immune-mediated inflammatory disease of the skin, which is characterized by epidermal hyperkeratosis and neutrophil infiltration. The interleukin (IL)-17/IL-23 pathway and associated cytokines play major roles in the pathogenesis and exacerbation of psoriasis. The IL-18/IL-18 receptor (R) α signaling pathway is important for Th1 cytokine production and differentiation of Th1 cells; however, its role in the pathogenesis of psoriasis remains unknown. In this study, we investigated the effect of the IL-18Rα-mediated signaling pathway in the pathogenesis of psoriasis in Il18ra-deficient mice (Il18ra-/-) and wild-type imiquimod (IMQ)-induced psoriatic dermatitis model mice. Blocking this pathway exacerbated IMQ-induced psoriatic skin inflammation. Il18ra deficiency led to significant increases in the levels of IL-1ß, IL-6, IL-8, IL-17A, IL-23, and chemokine (C-X-C motif) ligand 2 in skin lesions. Gr1-positive cells highly infiltrated psoriatic skin lesions in Il18ra-/- mice compared to those in wild-type mice. Citrullinated histone H3-positive area was relatively broad in Il18ra-/- mice. These results suggest that IL-18Rα-mediated signaling pathways may inhibit psoriatic skin inflammation by regulating infiltration and activation of neutrophil and other innate immune cells.