Abstract
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 Ca(2+) levels through the activation of store-operated Ca(2+) 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 Ca(2+) entry in the treatment of RA. To moderately suppress Ca(2+) 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 Ca(2+) 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 Ca(2+) entry through lentivirus-mediated CRACM3 gene silencing is beneficial in the treatment of RA.