Immune cells, including T cells, B cells, and osteoclasts, in conjunction with their associated cytokines, have been studied as primary molecular therapeutic targets for the management of rheumatoid arthritis (RA) patients. The increase in cytosolic Ca2+ levels through the activation of store-operated Ca2+ release–activated channels (CRACs) is involved in mediating a disparate array of cellular responses by these immune cells. This study was undertaken to investigate the feasibility and efficiency of the regulation of Ca2+ entry in the treatment of RA. To moderately suppress Ca2+ entry via CRACs, we gene silenced CRACM3, which was induced by systemic application of specific short hairpin RNAs (shRNAs) using a lentiviral-delivery system, in a murine model of collagen-induced arthritis (CIA). The inflammatory responses were determined by measuring the levels of a panel of cytokines and chemokines in the joints and serum. Ag-specific responses were evaluated by determining the cytokine profile of T cells stimulated with autoantigen. We also analyzed the ability of specific CRACM3-shRNA to regulate mature osteoclast function in CIA mice. The therapeutic effect of lentiviral-delivered CRACM3-shRNA was associated with gene silencing of CRACM3, along with the successful biodistribution of the virus. Extracellular Ca2+ influx in the splenocytes, thymocytes, and knee joint synovial cells was moderately suppressed. Inflammatory responses and autoimmune responses were reduced by CRACM3 gene silencing. A decrease in mature osteoclast activity also was observed in CRACM3-shRNA–treated CIA mice. These results indicate that regulation of Ca2+ entry through lentivirus-mediated CRACM3 gene silencing is beneficial in the treatment of RA.

Store-operated Ca release-activated Ca (CRAC) channels are involved in the pathogenesis of rheumatoid arthritis (RA) and have been studied as therapeutic targets in the management of RA. We investigated the efficacy and safety of CRAC inhibitors, including a neutralizing Ab (hCRACM1-IgG) and YM-58483, in the treatment of RA. Patient-derived T cell and B cell activity was suppressed by hCRACM1-IgG as well as YM-58483. Systemically constant, s.c. infused CRAC inhibitors showed anti-inflammatory activity in a human-NOD/SCID xenograft RA model as well as protective effects against the destruction of cartilage and bone. hCRACM1-IgG appeared to be safe for systemic application, whereas YM-58483 showed hepatic and renal toxicity in xenograft mice. Treatment with both CRAC inhibitors also caused hyperglycemia in xenograft mice. These results indicate the potential of hCRACM1-IgG and YM-58483 as anti-immunological agents for the treatment of RA. However, some safety issues should be addressed and application methods should be optimized prior to their clinical use.

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Molecular hydrogen is thought to have an inhibitory effect on oxidative stress, thereby attenuating the onset and progression of various diseases including cardiovascular disease; however, few reports have assessed the preventive effect of constitutive inhalation of hydrogen gas on of vascular remodeling. Here, we investigated the effect of constitutive inhalation of hydrogen gas on vascular neointima formation using a cuff-induced vascular injury mouse model. After constitutive inhalation of compressed hydrogen gas (O2 21%, N2 77.7%, hydrogen 1.3%) or compressed air only (O 2 21%, N 2 79%) by C57BL/6 mice for 2 weeks from 8 weeks of age in a closed chamber, inflammatory cuff injury was induced by polyethylene cuff placement around the femoral artery under anesthesia, and hydrogen gas administration was continued until sampling of the femoral artery. Neointima formation, accompanied by an increase in cell proliferation, was significantly attenuated in the hydrogen group compared with the control group. NADPH oxidase NOX1 downregulation in response to cuff injury was shown in the hydrogen group, but the expression levels of NADPH oxidase subunits, p40phox and p47phox, did not differ significantly between the hydrogen and control groups. Although the increase in superoxide anion production did not significantly differ between the hydrogen and control groups, DNA damage was decreased as a result of reduction of reactive oxygen species such as hydroxyl radical (�OH) and peroxynitrite (ONOO-) in the hydrogen group. These results demonstrate that constitutive inhalation of hydrogen gas attenuates vascular remodeling partly via reduction of oxidative stress, suggesting that constitutive inhalation of hydrogen gas at a safe concentration in the living environment could be an effective strategy for prevention of vascular diseases such as atherosclerosis.

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