AIM: To investigate the regulatory effect of miR-223-3p on the expression of transcription factor Rbpj and on the differentiation of Th1 and Th17 cells in experimental autoimmune uveitis(EAU)rats.

METHODS: The regulatory role of miR-223-3p in Rbpj gene expression was investigated by a dual luciferase expression reporter system. In the present study, 24 female Lewis rats were randomly divided into EAU model group, normal control(NC)group and blank control(BC)group, and each group included 8 rats. The EAU model group was injected with interphotoreceptor retinoid-binding protein(IRBP)emulsion containing Mycobacterium tuberculin H37RA and complete Freund's adjuvant to induce uveitis, while the NC group was injected with an equal volume of emulsion without IRBP peptide. The rats in the BC group received the same volume of sterile saline solution. At 12d after immunization, the spleen, lymph node and eye tissues in both groups were aseptically isolated, and the expression levels of miR-223-3p and Rbpj RNAs were detected by real-time quantitative PCR(Q-PCR); Meanwhile, the expression levels of Rbpj, IFN-γ and IL-17 proteins were detected by ELISA, and the levels of Th1 and Th17 cell lineages in each tissue from each groups were detected by flow cytometry.

RESULTS: The results of dual fluorescein assay indicated that Rbpj was the target gene which regulated by miR-223-3p. At 12d after immunization, compared with NC group, the relative expression levels of miR-223-3p in spleen, lymph node and eye tissues from EAU model rats were 0.33±0.29, 0.11±0.12 and 0.18±0.11, respectively, accompanied by the down-regulated expression, and the differences were statistically significant(all P<0.05); Rbpj mRNA levels were 3.00±0.06, 1.52±0.12 and 3.01±0.34, respectively, and were all up-regulated, while the differences were statistically significant(all P<0.05). Moreover, the differences in miR-223-3p and Rbpj mRNA levels in spleen, lymph node and eye tissues of rats in the blank control group were not statistically significant compared with those in the NC group(P>0.05); ELISA results revealed that the expression levels of RBPJ, IFN-γ and IL-17 proteins in all tissues from EAU rats at 12d after immunization were significantly higher than those in the NC group( all P<0.05), and there was no statistically significant difference in the expression levels of Rbpj, IFN-γ and IL-17 protein in all tissues of rats in the blank control group compared with the NC group(P>0.05); Meanwhile, flow cytometry results showed that the proportions of Th1 and Th17 cell lineages in all tissues from EAU model group were significantly higher than those from the NC group at 12d after immunization, and the differences were statistically significant(all P<0.05). Furthermore,there was no significant change in the proportion of Th1 and Th17 cells in each tissue in the BC and NC groups(all P >0.05).

CONCLUSION: The miR-223-3p can negatively regulate the expression of the transcription factor Rbpj of Notch signaling pathway. The down-regulated miR-223-3p expression in EAU rats can increase the expression levels of Rbpj gene and protein, and aggravate the differentiation of Th1 and Th17 cells and the expression levels of related molecules IFN-γ and IL-17, which in turn affect the development of uveitis.