| Abstract: | Objective Mediation of RNA interference by oligonucleotides constitutes a powerful approach for the silencing of genes involved in the pathogenesis of inflammatory disease, but in vivo application of this technique requires effective delivery to immune cells and/or sites of inflammation. The aim of the present study was to develop a new carrier system to mediate systemic administration of oligonucleotides to rheumatoid arthritis (RA) joints, and to develop an antisense oligonucleotide (ASO)–based approach to interfere with CD40–CD154 interactions in an experimental model of RA. Methods A novel liposomal carrier with amphoteric properties, termed Nov038, was developed and assessed for its ability to systemically deliver an ASO directed against CD40 (CD40‐ASO). Male DBA/1 mice with collagen‐induced arthritis were treated with Nov038‐encapsulated CD40‐ASO, and the effects of treatment on various parameters of disease activity, including clinical score, paw swelling, lymph node responses, and inflammatory cytokine production in the joints, were assessed. Results Nov038 was well tolerated, devoid of immune‐stimulatory effects, and efficacious in mediating systemic oligonucleotide delivery to sites of inflammation. In mice with collagen‐induced arthritis, Nov038 enabled the therapeutic administration of CD40‐ASO and improved established disease, while unassisted CD40‐ASO was ineffective, and anti–tumor necrosis factor α (anti‐TNFα) treatment was less effective in this model. Nov038/CD40‐ASO efficacy was attributed to its tropism for monocyte/macrophages and myeloid dendritic cells (DCs), resulting in rapid down‐regulation of CD40, inhibition of DC antigen presentation, and reduction in collagen‐specific T cell responses, as well as decreased levels of TNFα, interleukin‐6 (IL‐6), and IL‐17 in arthritic joints. Conclusion Amphoteric liposomes represent a novel carrier concept for systemic and antigen‐presenting cell–targeted oligonucleotide delivery with clinical applicability and numerous potential applications, including target validation in vivo and inflammatory disease therapeutics. Moreover, Nov038/CD40‐ASO constitutes a potent alternative to monoclonal antibody–based approaches for interfering with CD40–CD40L interactions. |
