Anti-inflammatory actions of ripasudil ameliorate experimental autoimmune uveoretinitis in the acute phase

Rho-associated protein kinases (ROCKs) are a key regulator of T cell function, influencing a wide range of processes from activation to differentiation. Experimental autoimmune uveoretinitis (EAU) is an animal model of human non-infectious uveitis. This study aimed to evaluate the suppressive effects of ripasudil, a ROCK inhibitor, on ocular inflammation when administered from the onset of EAU and to elucidate the underlying mechanisms of its inhibitory effects.

EAU was induced in wild-type C57BL/6 mice by immunisation with IRBP peptide. Ripasudil or its vehicle, PBS, was intraperitoneally administered daily starting from 8 days post-immunisation. Clinical and histopathological examinations and analysis of T cell activation state were conducted. In addition, T cell gene expression profiles in the relevant immune functions were identified using single-cell RNA sequencing (scRNA-seq).

The development of EAU was significantly attenuated and T cell activation and Th1 cell differentiation were significantly inhibited in mice with ripasudil (RIP-EAU) compared with mice with PBS (PBS-EAU), scRNA-seq using splenic T cells indicated that genes involved in the ROCK signalling pathway were highly expressed in low-differentiated Th1/Th17 cells, intermediate Th1 cells and differentiated Th1 cells. In addition, although differentiated Th1 and Th17 cells constituted similar proportions between PBS-EAU and RIP-EAU mice, RIP-EAU mice exhibited fewer low-differentiated Th1/Th17 cells and intermediate Th1 cells compared with PBS-EAU mice.

Ripasudil suppressed EAU when administered from the onset of the disease by inhibiting cells that strongly express genes involved in the ROCK signalling pathway and differentiate into Th1 cells.