Objective To investigate the effects of dimethyl itaconate(DMI)on the secretion of pro-inflammatory factors in dendritic cells(DCs)and on the interphotoreceptor retinoid-binding protein(IRBP)1-20-specific T helper 17(Th17)cells in mice with experimental autoimmune uveitis(EAU).Methods Bilateral femur and tibia of C57BL/6J mice were isolated to obtain bone marrow cells,and these bone marrow cells were directionally induced with granulocyte macrophage-colony-stimulating factor(GM-CSF)and interleukin(IL)-4 to differentiate DCs.After 6 days,DCs were ran-domly divided into the DMI group and the phosphate-buffered saline(PBS)group.Cells in the DMI group were pretreated with 250 μmol·L-1 DMI,and cells in the PBS group were pretreated with the same volume of PBS for 3 hours.After-wards,100 μg·L-1 lipopolysaccharide was added in the every group to stimulate cells for 24 hours.The relative mRNA ex-pression levels of IL-6,IL-1 β,and IL-23 in DCs were measured by quantitative real-time polymerase chain reaction(qRT-PCR).The EAU model was constructed by actively immunizing mice with IRBP1-20,Freund's incomplete adjuvant,and my-cobacterium tuberculosis H37RA.Thirteen days after immunization,T cells in the spleen and lymph node isolated from EAU mice were cocultured with DMI-treatedor PBS-treated DCs in the medium containing IRBP1-20.They polarized toward Th17 cells.The percentage of Th17 cells in the cocultured cells was detected by flow cytometry.The IL-17 level in the coculture supernatant was detected by enzyme-linked immunosorbent assay(ELISA).qRT-PCR was performed to detect the relative mRNA expression levels of retinoid-related orphan receptor gamma t(RORγt),IL-17,IL-23R,and GM-CSF in the cocultured cells.Results qRT-PCR analysis revealed that the relative mRNA expression levels of IL-6,IL-1β,and IL-23 in the DMI group were significantly lower thanthose in the PBS group(all P＜0.05).Flow cytometry analysis showed that the proportion of Th17 cells in the cocultured cells in the DMI group was significantly lower than that in the PBS group(P＜0.05).ELISA analysis exhibited that the IL-17 level in the coculture supernatant in the DMI group was significantly lower than that in the PBS group(P＜0.05).The relative mRNA expression levels of IL-17,ROR-γt,IL-23R and GM-CSF in cocultured cells in the DMI group significantly decreased compared with the PBS group(all P＜0.05).Conclusion DMI can reduce the expression of IL-6,IL-1β and IL-23 in DCs,thus negatively modulating the responses of IRBP1-20-specific Th17 cells.

Objective:To investigate the effect of long noncoding RNA (lncRNA) 5033413D16Rik (lncRNA 5033413D16Rik) on the activity of interphotoreceptor retinoid-binding protein 1-20 (IRBP) 1-20-specific T helper 17 (Th17) cells in experimental autoimmune uveitis (EAU). Methods:Twelve SPF grade C57BL/6 female mice aged 8 to 10 weeks were selected and divided into EAU group and normal control group using the random number table method, with 6 mice in each group.Mice in the normal control group received no treatment.Mice in the EAU group were immunized with IRBP 1-20 emulsified in complete Freund's adjuvant to induce EAU.On day 13 after immunization, fundus examination and inflammation scoring were performed, and retinal histopathological changes were observed with hematoxylin and eosin staining.T cells were isolated from the spleen and lymph nodes of EAU mice, and the relative expression of lncRNA 5033413D16Rik was detected by real-time fluorescence quantitative PCR (qRT-PCR).In addition, the isolated T cells were divided into short hairpin RNA (shRNA)-5033413D16Rik transfected group and shRNA-negative control (NC) transfected group, and transfected with corresponding shRNAs, respectively.The knockdown efficiency of shRNA-5033413D16Rik was verified by qRT-PCR.T cells in the two groups were co-cultured with bone marrow-derived dendritic cells (BMDCs) under Th17 polarizing conditions.The relative expression of retinoic acid-related orphan receptor (RORγt), interleukin 17 (IL-17), IL-23 receptor (IL-23R), and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA in co-cultured cells were analyzed by qRT-PCR.The IL-17 concentration in co-culture supernatants was assayed by ELISA and percentages of Th17 cells were determined by flow cytometry.The use and care of experimental animals complied with the Regulations for the Administration of Affairs Concerning Experimental Animals promulgated by the State Science and Technology Commission.The study protocol was reviewed and approved by the Experimental Animal Ethics Committee of Tianjin Medical University (No.TJYY2019110117). Results:EAU model was established successfully.qRT-PCR analysis showed that the expression of lncRNA 5033413D16Rik was significantly decreased in T cells from EAU mice compared with normal control mice ( t=-13.332, P<0.001).Compared with the shRNA-NC transfected group, the relative expression of lncRNA 5033413D16Rik in T cells of the shRNA-5033413D16Rik transfected group was significantly reduced ( t=-6.338, P<0.01).In co-cultured T cells, the expression levels of RORγt, IL-17, IL-23R, and GM-CSF mRNA in shRNA-5033413D16Rik transfected group were 1.61±0.13, 1.51±0.13, 1.85±0.33 and 1.45±0.11, which were significantly higher than 1.00±0.01, 1.00±0.01, 1.00±0.01 and 1.00±0.01 in shRNA-NC-transfected group ( t=-6.839, -8.221, -4.538, -4.189; all at P<0.05).ELISA analysis revealed that IL-17 concentraion in shRNA-5033413D16Rik transfected group was (2 350.39±367.02)pg/ml, which was significantly higher than (1 513.31±310.37)pg/ml ( t=-3.016, P=0.039).Flow cytometry showed that the percentage of Th17 cells in shRNA-5033413D16Rik transfected group was (17.20±0.44)%, which was higher than (14.10±0.84)% in normal control group ( t=-3.264, P=0.031). Conclusions:LncRNA 5033413D16Rik can inhibit the expression of pathogenicity related genes in antigen-specific Th17 cells and negatively regulates IRBP 1-20-specific Th17 cell responses.