Successful treatment with a novel immunosuppressive agent, deoxyspergualin, in type II collagen-induced arthritis in mice

Methods for Testing Immunological Factors

Hypersensitivity reactions can be elicited by various factors: either immunologically induced, i.e., allergic reactions to natural or synthetic compounds mediated by IgE, or non-immunologically induced, i.e., activation of mediator release from cells through direct contact, without the induction of, or the mediation through immune responses. Mediators responsible for hypersensitivity reactions are released from mast cells. An important preformed mediator of allergic reactions found in these cells is histamine. Specific allergens or the calcium ionophore 48/80 induce release of histamine from mast cells. The histamine concentration can be determined with the o-phthalaldehyde reaction.

A new phenylpyrazoleanilide, y-320, inhibits interleukin 17 production and ameliorates collagen-induced arthritis in mice and cynomolgus monkeys

Interleukin (IL)-15 and IL-17 are thought to play an important role in the pathogenesis of rheumatoid arthritis (RA) because both pro-inflammatory cytokines are found in synovial fluid of RA patients. In this study, we examined the pharmacological profiles of Y-320, a new phenylpyrazoleanilide immunomodulator. Y-320 inhibited IL-17 production by CD4 T cells stimulated with IL-15 with IC₅₀ values of 20 to 60 nM. Oral administration of Y-320 (0.3 to 3 mg/kg) significantly inhibited the development and progression of arthritis and joint destruction with reduction of IL-17 mRNA expression in arthritic joints of type II collagen-induced arthritis (CIA) in DBA/1J mice. Y-320 in combination with anti-murine tumor necrosis factor-α monoclonal antibody showed a synergistic effect on mouse CIA. Moreover, therapeutic treatment with Y-320 (0.3 and 1 mg/kg orally) ameliorated CIA in cynomolgus monkeys. Our results suggest that Y-320, an orally active inhibitor for IL-17 production, provides a useful therapy for RA.

Angiogenesis in rheumatoid arthritis

Angiogenesis is the formation of new capillaries from pre-existing vessels. A number of soluble and cell-bound factors may stimulate neovascularization. The perpetuation of angiogenesis involving numerous soluble and cell surface-bound mediators has been associated with rheumatoid arthritis (RA). These angiogenic mediators, among others, include growth factors, primarily vascular endothelial growth factor (VEGF) and hypoxia-inducible factors (HIFs), as well as pro-inflammatory cytokines, various chemokines, matrix components, cell adhesion molecules, proteases and others. Among the several potential angiogenesis inhibitors, targeting of VEGF, HIF-1, angiogenic chemokines, tumor necrosis factor-alpha and the alpha(V)beta(3) integrin may attenuate the action of angiogenic mediators and thus synovial angiogenesis. In addition, some naturally produced or synthetic compounds including angiostatin, endostatin, paclitaxel, fumagillin analogues, 2-methoxyestradiol and thalidomide may be included in the management of RA.

Function and dysfunction of dendritic cells in autoimmune rheumatic diseases

Dendritic cells (DC) have been implicated both in initiation of immunity and in immune tolerance. The mechanisms whereby tolerogenic DC may induce and maintain peripheral tolerance include the generation or expansion of regulatory T cells (Treg) and the promotion of T-cell anergy or deletion. A wide spectrum of hematopoietic growth factors and cytokines are endowed with the ability to differentiate tolerogenic DC both in vitro and in vivo. Based on this knowledge, therapeutic vaccination with cytokine-modulated tolerogenic DC has been applied to animal models of autoimmune disorders. This article will review the current experimental evidence underpinning DC dysfunction in rheumatic autoimmune diseases and will discuss how the manipulation of DC and Treg number and function may control undesired T-cell responses.

Edaravone inhibits collagen-induced arthritis possibly through suppression of nuclear factor-kappa B

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic autoimmune disease which is induced by proinflammatory cytokines or oxidative stress. The activation of nuclear factor-kappa B (NF-kappaB) that contributed to imbalance between apoptosis and proliferation of rheumatoid synovial cells (SC). Edaravone, clinically available free radical scavenger in Japan, is confirmed to be beneficial in the acute stage of stroke. We aimed to investigate the suppressive effect of edaravone on collagen-induced arthritis (CIA) mice and on the activated molecules in SC stimulated by interleukin-1beta (IL-1beta).

METHODS

Edaravone was administrated intravenously at a dose of 3mg/kg of body weight to CIA mice. The progression of CIA was evaluated by the macroscopic arthritis scoring system of paws. Interleukin-6 (IL-6) and matrix metalloproteinase-3 (MMP-3) concentrations in culture medium of human SC were measured by enzyme linked immunosorbent assays. Caspase-3/7 activity and nuclear factor-kappa B (NF-kappaB) protein level of cultured human SC were estimated by fluorometric assay and Western blot analysis, respectively.

RESULTS

Edaravone significantly decreased macroscopic arthritis score in CIA mice. Acceleration of IL-6 and MMP-3 productions and attenuation of caspase-3/7 activity in IL-1beta-stimulated SC were abated by edaravone. Activated NF-kappaB in IL-1beta-stimulated SC was suppressed by edaravone.

CONCLUSION

Edaravone, antioxidants available for clinical use, appears to have therapeutic effect on RA. We suggest that the inhibitory effect of edaravone on RA might be exerted, at least in part, through suppression of activated NF-kappaB. Therefore, we expect therapeutical use of edaravone as an anti-rheumatic agent.

NK95806, a newly synthesized microtubule-disrupting agent that suppresses collagen-induced arthritis in mice

We investigated the anti-arthritic effects of NK95806, a novel inhibitor of microtubule polymerization, on collagen-induced arthritis in mice. The suppressive effect of NK95806 on the induction and development of arthritis was shown as a significant reduction in clinical arthritis scores. Histological analysis of the hind paws confirmed the improvement in clinical severity and showed marked decreases in granulomatous formation and further bone destruction. Further, under the experimental conditions in which methotrexate had little, if any, effect, NK95806 significantly suppressed the development of arthritis. These results suggest that the disruption of microtubules might be a novel target for anti-rheumatic drugs and NK95806 may be a candidate for further development.

Immunosuppressive effect of deoxyspergualin in proliferative glomerulonephritis

A clinical trial of the immunosuppressive drug deoxyspergualin (DSG) was conducted in five patients with various forms of proliferative glomerulonephritis (immunoglobulin A nephropathy in two patients, purpura nephritis in one patient, membranoproliferative glomerulonephritis in one patient, and rapidly progressive glomerulonephritis in one patient). DSG was intravenously administered at 0.25 or 0.5 mg/kg/d for 4 weeks. A marked decrease in proteinuria (to <50% of baseline) was observed in four patients, and the other patient showed a 38% reduction in proteinuria, but the proteinuria was exacerbated again after discontinuation of DSG in three patients during a 4-week follow-up period. Proinflammatory CD16(+) (FcgammaRIII) monocytes disappeared from the peripheral blood during the administration of DSG but reappeared after DSG treatment was discontinued. A significant decrease in urinary macrophage counts that was far more marked than the decrease in peripheral blood monocyte counts was observed after administration of DSG. Interestingly, we also observed that the CD16 marker on the CD14(+) macrophage population in the urine disappeared in response to DSG treatment. These findings suggest that DSG may have a unique effect of suppression of FcgammaRIII expression on monocytes and/or macrophages that may result in amelioration of activated macrophage-mediated glomerulonephritis.