Background/Purpose: In recent years, one widespread and potentially important Ca²⁺ channel, store-operated Ca²⁺-release-activated Ca²⁺ (CRAC) channel is raised in drug discovery for rheumatoid arthritis (RA). Ca²⁺ entry through CRAC channels drives exocytosis, stimulates mitochondrial metabolism, activates gene expression and promote cell growth and proliferation in non-exitable cells. Downregulation of the CRAC channels lead to irregular functions of T cells, B cells and osteoclasts, which contribute to RA pathogenesis. The present study was undertaken to investigate the feasibility and efficiency of partially regulation of the Ca²⁺ influx via CRAC channel by CRACM3 gene-silencing for the treatment of RA.

Methods: We evaluated the therapeutic potential of CRACM3 gene-silencing by systemic delivery of lentivirus expressing CRACM3-shRNA (Lenti-M3shRNA) in a collagen-induced arthritis (CIA) mouse model. The inflammatory response was assessed by measuring the levels of inflammatory cytokines in joint and serum. The cytokine profile of T cells stimulated with autoantigen was also determined. Mature osteoclast function was analyzed using tartrate-resistant acid phosphatase (TRAP) staining and pit formation assay.

Results: The intraperitoneal injection (10⁹ particles/7 days) of Lenti-M3shRNA was highly effective in treating CIA. Ca²⁺ influxes in splenocytes, thymocytes, and synovial cells were partially blocked by gene-silencing of CRACM3. CIA mice showed significant regression of the disease after Lenti-M3shRNA treatment. The autoimmune response, which was assessed using self-reactive Th1 cell activity and autoantibody production, was significantly suppressed by M3shRNA administration. Low level of the resorptive capacity in mature osteoclasts was also observed in Lenti-M3shRNA treated CIA mice according to the results of TRAP staining and pit formation assay.

Conclusion: Our findings indicate that in vivo gene-silencing CRACM3 by systemic delivery of Lenti-M3shRNA may have beneficial therapeutic effects on RA. Our findings provide valuable insight into the potential ways that CRACMs could contribute to RA pathogenesis and support the idea that targeting CRAC channels might offer an effective strategy for the treatment of RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/systemic-delivery-of-short-hairpin-rna-targeting-calcium-release-activated-calcium-channel-3-down-regulates-severity-of-collagen-induced-arthritis/