Silencing RORγt in Human CD4⁺ T cells with CD30 aptamer-RORγt shRNA Chimera

Targeting specific T cell subtypes and intervening in their function are emerging a critical strategy for treatment of autoimmune diseases. Here we report that an RNA CD30 aptamer was utilized to deliver short hairpin RNA (shRNA) to CD30⁺ T cells to target retinoic acid receptor-related orphan receptor gamma t (RORγt), leading to impaired expression of RORγt and suppression of IL-17A and IL-17F. A DNA template consisting of CD30 aptamer and RORγt shRNA sequences was synthesized and was transcribed CD30 aptamer-RORγt shRNA chimera (CD30-AshR-RORγt). Insertion of 2'-F-dCTP and 2'-FdUTP was incorporated during CD30-AshR-RORγt transcription to increase its resistance to RNase. CD30-AshR-RORγt was specifically up-taken by CD30⁺ Karpas 299 cells, but not by Jurkat cells which lack CD30. It was also up-taken by activated, CD30 expressing human CD4⁺T cells, but not by resting CD4⁺ T cells. The RORγt shRNA moiety of CD30-AshR-RORγt chimera was cleaved and released by Dicers. Then, CD30-AshR-RORγt suppressed RORγt gene expression in Karpas 299 cells and activated human CD4⁺ T cells. Consistently, silence of Th17 cell differentiation and IL-17A and IL-17F synthesis with CD30-AshR-RORγt was demonstrated in activated human CD4⁺ T cells from healthy donors and RA patients. CD30-AshR-negative control chimera and prostate specific membrane antigen (PSMA)-AshR-RORγt had no significant impact on the expression of RORγt or IL-17A and IL-17F. These data present a novel strategy for shRNA delivery using CD30 RNA aptamers to down-regulate CD30⁺ Th17 cells and can be developed as a targeted therapy for treating Th17 cell mediated conditions.