Delivery Of SiRNA Targeting BTK With Nanoparticles For Rheumatoid Arthritis Therapy

Rheumatoid arthritis(RA)is a long-tern,autoimmune disease associated with chronic inflammation.Currently,the treatment of rheumatoid arthritis is mainly to intervene in the excessive immune response during the disease,such as using small immunosuppressant molecule methotrexate,leflunomide and antibody therapy like adalimumab to inhibit inflammation and alleviating the symptoms of the disease.Howerver,long-term use of the drugs leads to systemic immunosuppression which in turn increases the risk of subsequent infection.Therefore,there is still a requirement to develop new rheumatoid arthritis treatment strategies.Small interfering RNA(siRNA),as an effective means of gene silencing,has araised more and more attention and been used widely in recent years.But at the same time,the application of siRNA also has problems,such as easily degradation by nuclease in vivo.Our lab previously reported a double-emulsified nanoparticle for siRNA delivery using block copolymer of poly(ethylene glycol)-b-poly(lacide-co-glycolide)(PEG-b-PLGA)assisted with cationic lipid.And siRNA was successfully delivered to target cells to silence related gene expression,which in turn reached the therapeutic effect of various diseases.Bruton’s tyrosine kinase(BTK)plays an important role in B cell maturation and inflammatory response of macrophages.Some studies have shown that inhibition of BTK activity in B cells and macrophages by small molecule inhibitors can effecitively prevent and threat the mouse models of rheumatoid arthritis.In this study,in order to select a better nanoparticle for siRNA delivery of B cells and macrophages,we constructed a series of cationic lipid-assisted PEG-b-PLGA nanoparticle(CLAN)with different charateristics,such different PEG densities,charge and cationic lipids.After inj ection via the tail vein,the nanoparticles uptake of B cells,macrophages and neutrophils were detected in blood and spleen.The nanoparticles which were well taken up in B cells and macrophages was chosen.And then,we encapsulated the siRNA targeting BTK(siBTK)into CLAN and tested the gene silencing efficiency in B cells and macrophages both in vitro and in vivo.The uptake of the nanoparticle by B cells and macrophages in more immune organs was detected in mice.Finally,in the collagen-induced arthritis mouse model,we demonstrated the CLANsiBTK could effectively reduce the symptoms of arthritis,joint damage caused by disease and inhibit the expression of inflammatory factors.This study provides a new idea for the treatment of a variety of autoimmune disease associated with autoimmune antibodies and inflammation.