Dysregulation of Rnf 213 gene contributes to T cell response via antigen uptake, processing, and presentation

Growing evidence suggest the association between Moyamoya disease (MMD) and immune systems, such as antigen presenting cells in particular. Rnf213 gene, a susceptibility gene for MMD, is highly expressed in immune tissues, however, its function remains unclear. In addition, the physiological role of RNF213 gene polymorphism c.14576G > A (rs112735431), susceptibility variant for MMD, is also poorly understood. By studying Rnf213-knockout (Rnf213-KO) mice with deletion of largest exon32 and Rnf213-knockin (Rnf213-KI) mice with insertion of single-nucleotide polymorphism corresponding to c.14576G > A mutation in MMD patients, we aimed to investigate the role of RNF213 in dendritic cell development, and antigen processing and presentation. First, we found a high level of Rnf213 gene expression in conventional DCs and monocytes. Second, flow cytometric and confocal microscopic analysis revealed ovalbumin protein-pulsed Rnf213-KO and Rnf213-KI DCs showed impaired antigen uptake, proteolysis and reduced numbers of endosomes and lysosomes, and thereby failed to activate and proliferate antigen-specific T cells efficiently. In addition, Rnf213-KI DCs showed a similar phenotype to that of Rnf213-KO BMDCs. In conclusion, our findings suggest the critical role of RNF213 in antigen uptake, processing and presentation.