Rapamycin ameliorates experimental autoimmune uveoretinitis by inhibiting Th1/Th2/Th17 cells and upregulating CD4+CD25+ Foxp3 regulatory T cells

· AIM: To determine the effects of rapamycin on experimental autoimmune uveoretinitis(EAU) and investigate of role of rapamycin on T cell subsets in the disease.·METHODS: EAU was induced in rats using peptides1169 to 1191 of the interphotoreceptor binding protein(IRBP). Rapamycin(0.2 mg/kg/d) was administrated by intraperitoneal injection for a consecutive 7d after immunization. Th1/Th2/Th17 cytokines, TGF-β1, and IL-6produced by lymphocyteswere measured by ELISA, while Th17 cells and CD4 +CD25 + regulatory T cells(Tregs)from rat spleen were detected by flow cytometry.·RESULTS: Intraperitoneal treatment immediately after immunization dramatically ameliorated the clinical course of EAU. Clinical responses were associated with reduced retinal inflammatory cell infiltration and tissue destruction. Rapamycin induced suppression of Th1/Th2/Th17 cytokines, including IFN-γ, IL-2, IL-17, IL-4, and IL-10 release from T lymphocytes of EAU rats, in vitro.Rapamycin also significantly increased TGF-β1production but had no effect on IL-6 productionof T lymphocytes from EAU rats in vitro. Furthermore,rapamycin decreased the ratio of Th17 cells/CD4 +T cells and upregulated Tregs in EAU, as detected by flow cytometry.·CONCLUSION: Rapamycin effectively interferes with T cell mediated autoimmune uveitis by inhibiting antigen-specific T cell functions and enhancing Tregs in EAU.Rapamycin is a promising new alternative as an adjunct corticosteroid-sparing agent for treating uveitis.

Apoptosis of infiltrating cells in experimental autoimmune uveoretinitis

To investigate the cellular phenotype and apoptosis of infiltrating cells involved in experimental autoimmune uveoretinitis (EAU) Methods Immunohistochemical staining and in situ apoptosis staining were performed using monoclonal antibodies to monocytes and macrophages (ED1), major histocompatibility complex (MHC) class Ⅱ antigen (OX6), T lymphocytes (R73) and TACS 1 Klenow kit on both ocular sections and wholemounts from Lewis rats after immunization with interphotoreceptor retinoid binding protein (IRBP) Results EAU was induced in 12 of 16 Lewis rats with a mean clinical inflammation score of 1 29±0 7 Influx of monocytes, lymphocytes and MHC class Ⅱ positive cells into the uvea and retina was noted after immunization with IRBP Apoptosis of infiltrating cells was observed in the uvea and retina, and more apoptotic cells were present in the iris and ciliary body compared with those in the choroid and retina Conclusion Apoptosis of infiltrating cells occurs at the early stage of EAU, which may greatly contribute to the rapid regression of the inflammation induced by IRBP

Osteopontin is a biomarker for early autoimmune uveoretinitis

Osteopontin(OPN)is an extracellular matrix protein with a diverse range of functions,including roles in cell adhesion,migration,and immunomodulation,which are associated with the modulation of neuroinflammation in the central nervous system.The present study was performed to evaluate the involvement of OPN in the eyes of an experimental autoimmune uveoretinitis(EAU)model.The EAU model was developed by immunization of Lewis rats with interphotoreceptor retinoid-binding protein.The results showed the OPN level was remarkably upregulated in the eye of EAU rats on day 9 post-immunization.The level of CD44,a ligand of OPN,was increased in the ciliary body of EAU rats.Furthermore,OPN was also detected in the ciliary body and activated microglia/macrophages in the EAU retina.The results suggest that OPN was significantly upregulated in the eyes of EAU rats,and that it may be useful as an early biomarker of ocular autoimmune diseases.All animal experiments were approved by the Institutional Animal Care and Use Committee of Jeju National University(approval No.2020-0012)on March 11,2020.