ROS-NLRP3 Axis in Intestinal Epithelial Cells is Involved in the Development of Autoimmune Uveitis

Uveitis is a irreversible blinding eye disease with unknown mechanism. The imbalance of Treg/Th17 caused by the interaction of genetics and environment is the core mechanism of the occurrence and development of uveitis. We aimed to confirm that intestinal immune imbalance aggravates uveitis.

The experimental autoimmune uveitis (EAU) model was established by immunizing mice with IRBP1-20. Flow cytometry was used to detect the expression of CD4 + T lymphocytes, dendritic cells and memory CD4 + T cells in the intestinal lamina propria on days 7 and 14 of induction. Fitc-dextran test was used to detect intestinal permeability, and RT-PCR was used to detect the expression of occludin and ZO-1 in intestinal epithelial cells. The ROS level in intestinal epithelial cells was detected by ROS probe, and the expression levels of NLRP3 inflammasome, caspase-1 and IL-1β in intestinal epithelial cells were detected by WB. In addition, antioxidant was administered via intraperitoneal injection to induce protection against EAU, clinical scores were used to assess disease progression. Flow cytometry was used to detect the proportion of Th17 and Treg cells in the mesenteric draining lymph nodes.

In the early stages of EAU, CD4+ T cells, dendritic cells, and memory CD4+ T cells were observed in the intestinal lamina propria. Additionally, dysfunction of the intestinal epithelial barrier was characterized by increased FITC-dextran permeability and decreased occludin and ZO-1 expression, highlighting its role in the pathogenesis of EAU. Notably, we also detected elevated levels of ROS, NLRP3 inflammasome, caspase-1, and IL-1β in the intestinal epithelium of EAU mice. Antioxidant treatment in EAU mice demonstrated a protective effect by inhibiting the expression of ROS, NLRP3, caspase-1, and IL-1β in intestinal epithelial cells.

Activation of the intestinal ROS-NLRP3 axis leads to a disruption in the balance between Teff cells and Treg cells, contributing to the pathogenesis of uveitis.