YY1 Lactylation Aggravates Autoimmune Uveitis by Enhancing Microglial Functions via Inflammatory Genes.

Activated microglia in the retina are essential for the development of autoimmune uveitis. Yin-Yang 1 (YY1) is an important transcription factor that participates in multiple inflammatory and immune-mediated diseases. Here, an increased YY1 lactylation in retinal microglia within in the experimental autoimmune uveitis (EAU) group is observed. YY1 lactylation contributed to boosting microglial activation and promoting their proliferation and migration abilities. Inhibition of lactylation suppressed microglial activation and attenuated inflammation in EAU. Mechanistically, cleavage under targets & tagmentation ï¼ˆCUT&Tag） analysis revealed that YY1 lactylation promoted microglial activation by regulating the transcription of a set of inflammatory genes, including STAT3, CCL5, IRF1, IDO1, and SEMA4D. In addition, p300 is identified as the writer of YY1 lactylation. Inhibition of p300 decreased YY1 lactylation and suppressed microglial inflammation in vivo and in vitro. Collectively, the results showed that YY1 lactylation promoted microglial dysfunction in autoimmune uveitis by upregulating inflammatory cytokine secretion and boosting cell migration and proliferation. Therapeutic effects can be achieved by targeting the lactate/p300/YY1 lactylation/inflammatory genes axis.

iPSC-based model of Vogt-Koyanagi-Harada disease for phenotype recapitulation and drug screening.

Vogt-Koyanagi-Harada (VKH) disease, a major blinding eye disease, is characterized by an autoimmune response against melanocytes in multiple organs throughout the body. Currently, the aetiology and pathogenesis of VKH disease are unclear, and the treatment strategy needs to be further optimized. The retinal pigment epithelium (RPE), a monolayer of pigmented cells of the fundus, is essential for maintaining normal visual function and is involved in both the acute and chronic stages of VKH disease. Therefore, the functions of the RPE may play a critical role in the aetiology and treatment of VKH disease. Herein, we established a human induced pluripotent stem cell (hiPSC) RPE model of VKH disease by reprogramming peripheral blood mononuclear cells (PBMCs) into iPSCs and then differentiating them into RPE cells. Patient-derived RPE cells exhibited barrier disruption, impaired phagocytosis, and depigmentation compared with those from normal controls, which was consistent with the features of VKH disease. Furthermore, a small molecular compound targeting EGR2 was found to rescue the barrier and phagocytic functions of the hiPSC-RPE cells through high-throughput virtual screening and functional studies, suggesting a promising strategy for the treatment of VKH disease.

Higher 25-hydroxyvitamin D level is associated with increased risk for Behçet's disease.

BACKGROUND & AIM: Previous studies showed a vitamin D deficiency in patients with Behçet's disease, suggesting potential benefits of vitamin D supplementation in the prevention and treatment of Behçet's disease. Interpretation of these studies may be limited by reverse causality or confounding bias. We aim to determine the causal association between serum 25-hydroxyvitamin D [25(OH)D] and the risk of Behçet's disease by Mendelian randomization. METHODS: An allele score formed by four variants (rs2282679, rs10741657, rs12785878 and rs6013897) that were associated with serum 25(OH)D level, was examined using data of genome-wide association study (GWAS) on 999 Behçet's disease and 4417 healthy individuals of Chinese ancestry and validated using data of GWAS on 1215 Behçet's disease and 1278 controls of Turkish ancestry. The primary outcome was the risk of Behçet's disease, evaluated by an inverse variance weighted average of the associations with genetically determined 25(OH)D levels. RESULTS: The inverse variance weighted estimate showed that genetically increased 25(OH)D level was associated with a higher risk of Behçet's disease. In the Chinese cohort, the odds ratio for Behçet's disease in one standard deviation increase of natural log-transformed 25(OH)D level was 3.82 (95% CI: 1.27-11.42). Data from Turkish cohort confirmed the association with Behçet's disease (OR, 95% CI: 4.18, 1.15-15.12). In overall combination of Chinese and Turkish cohorts, the odds ratio for Behçet's disease per standard deviation increase of natural log-transformed 25(OH)D level was estimated to be 3.96 (95% CI: 1.72-9.13; P = 0.001). No significant evidence of pleiotropy and heterogeneity was detected. CONCLUSIONS: On the basis of evidence in 7909 human beings, this study provides the newest indication that a lifelong higher 25(OH)D level is associated with an increased risk of Behçet's disease. Special attention should be paid to the potential harm of long-term or high-dose use of vitamin D supplements in clinical practice.

Effect of berberine on spleen transcriptome and gut microbiota composition in experimental autoimmune uveitis.

BACKGROUND: Berberine (BBR) was reported to have immunoregulatory and anti-inflammatory properties. In this study, we investigated whether BBR could exert its effects on the development of experimental autoimmune uveitis (EAU), and if so, what was the underlying mechanism? METHODS: EAU was induced in B10R.III mice by immunization with IRBP 161-180, followed by 100 mg/kg/d BBR intragastric administration. Disease severity was assessed by evaluation of clinical and histopathological scores. Blood-retinal barrier (BRB) breakdown was tested by Evans blue. Effector and regulatory T (Treg) cell balance was evaluated by quantitative real-time PCR and flow cytometry. Spleen transcriptome was characterized by RNA sequencing (RNA-seq). Gut microbiota composition was investigated by 16S rRNA analysis. RESULTS: BBR treatment significantly blocked EAU as shown by the decrease of the clinical and histological scores, as well as the inhibition of BRB breakdown. The frequency of splenic Th1 and Th17 cells was decreased, whereas Treg cells were increased in the BBR-treated group. RNA-seq of the spleen revealed 476 differentially expressed genes (DEGs) between the EAU and EAU-BBR group. GO functional classification, as well as KEGG analysis demonstrated that BBR treatment markedly influences genes belonging to chromatin remodeling and immune-related pathways. Intervention with BBR modified the gut microbiome in EAU mice, increasing the number of bacteria with immunomodulatory capacity. Depletion of gut microbiota affected the efficacy of BBR on EAU. Moreover, the altered bacterial strains showed a significant correlation with the expression of histones. CONCLUSIONS: BBR inhibited IRBP induced EAU, which was associated with a significant change in the spleen transcriptome and intestinal microbial composition.

Effect of berberine on proinflammatory cytokine production by ARPE-19 cells following stimulation with tumor necrosis factor-α.

PURPOSE: Berberine (BBR) is a well-known drug used in traditional medicine and has been shown to possess anti-inflammatory properties. Whether it can affect the production of inflammatory cytokines by RPE cells is not yet clear and was therefore the subject of our study. METHODS: ARPE-19 cells were cultured with TNF-α in the presence or absence of BBR to different time points. Concentrations of IL-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) in the supernatant were measured by using an ELISA. The mRNA expression of these cytokines was measured by real-time PCR. Phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK) was measured by Western blot assay. The signal transduction mechanisms involved in cytokine production were evaluated using various inhibitors for p38, ERK1/2, and JNK. RESULTS: TNF-α significantly increased the expression of IL-6, IL-8, and MCP-1 in ARPE-19 cells at both the protein and mRNA levels. It promoted the phosphorylation of p38, ERK1/2, and JNK. Inhibitory experiments showed that IL-6 was modulated by p38, whereas IL-8 and MCP-1 were modulated by p38, ERK1/2, and JNK signal pathways. BBR inhibited the expression of IL-6, IL-8, and MCP-1 remarkably at both protein and mRNA levels and down-regulated the phosphorylation of p38, ERK1/2, and JNK upon stimulation with TNF-α. CONCLUSIONS: The present results suggested that BBR significantly inhibits the expression of inflammatory cytokines in ARPE-19 cells and that the inhibitory effect is mediated by down-regulation of the p38, ERK1/2, and JNK pathways.

Regulatory effects of IFN-ß on the development of experimental autoimmune uveoretinitis in B10RIII mice.

BACKGROUND: Experimental autoimmune uveoretinitis (EAU) serves as a model for human intraocular inflammation. IFN-ß has been used in the treatment of certain autoimmune diseases. Earlier studies showed that it ameliorated EAU; however, the mechanisms involved in this inhibition are still largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: B10RIII mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) peptide 161-180 in Complete Freund's adjuvant. Splenocytes from different time points after immunization were used to evaluate the expression of IFN-ß. An increased expression of IFN-ß was observed during EAU and its highest expression was observed on day 16, 3 days after the peak of intraocular inflammation. Splenocytes and draining lymph node cells from mice immunized with IRBP(161-180) on day 13 and control mice were activated with anti-CD3/anti-CD28 antibodies or IRBP(161-180) to evaluate the production of IFN-γ and IL-17. The results showed that IFN-γ and IL-17 were significantly higher in immunized mice as compared to the control mice when exposed to anti-CD3/anti-CD28 antibodies. However, the production of IFN-γ and IL-17 was detected only in immunized mice, but not in the control mice when stimulated with IRBP(161-180). Multiple subcutaneous injections of IFN-ß significantly inhibited EAU activity in association with a down-regulated expression of IFN-γ, IL-17 and an enhanced IL-10 production. In an in vitro system using cells from mice, IFN-ß suppressed IFN-γ production by CD4(+)CD62L(-) T cells, IL-17 production by CD4(+)CD62L(+/-) T cells and proliferation of CD4(+)CD62L(+/-) T cells. IFN-ß inhibited the secretion of IL-6, but promoted the secretion of IL-10 by monocytes. IFN-ß-treated monocytes inhibited IL-17 secretion by CD4(+)CD62L(+/-) T cells, but did not influence IFN-γ expression and T cell proliferation. CONCLUSIONS/SIGNIFICANCE: IFN-ß may exert its inhibitory effect on EAU by inhibiting Th1, Th17 cells and modulating relevant cytokines. IFN-ß may provide a potential treatment for diseases mediated by Th1 and Th17 cells.

Increased Regulatory T Cells in Spleen during Experimental Autoimmune Uveoretinitis.

PURPOSE: To investigate the role of Foxp3-positive regulatory T cells in the development of experimental autoimmune uveoretinitis (EAU). METHODS: B10RIII mice were immunized with 50 microg IRBP(161-180) in complete Freund's adjuvant (CFA) to induce EAU. EAU was evaluated clinically and pathologically on days 0, 7, 14, 21, and 28. Foxp3 mRNA levels were detected using reverse transcription-PCR (RT-PCR) and the frequencies of CD4(+)Foxp3(+) T cells and CD4(+)CD25(+)Foxp3(+) T cells in splenocytes were assessed by flow cytometry at the aforementioned time points. RESULTS: The first clinical signs of EAU were observed on day 8-9, worsened up to day 14, and then gradually resolved. Histopathologic results showed that inflammatory signs occurred on day 7, reached their peak on day 14, and then gradually decreased. The levels of Foxp3 mRNA and the frequencies of CD4(+)Foxp3(+) T cells and CD4(+)CD25(+)Foxp3(+) T cells in splenocytes increased on day 7, reached a peak on day 14, and then maintained at a high level until day 28. CONCLUSION: An upregulation of Foxp3 expression is induced in EAU and paralleled with disease activity, suggesting a role for this lymphocyte subpopulation in the regression of this experimental uveitis model.

Contribution of CD4+CD25+ T cells to the regression phase of experimental autoimmune uveoretinitis.

PURPOSE: To investigate the role of CD4(+)CD25(+) Treg cells in the development of experimental autoimmune uveoretinitis (EAU). METHODS: EAU was induced in B10RIII mice by immunization with IRBP(161-180) in complete Freund's adjuvant and evaluated clinically and pathologically on days 0, 7, 14, 21, and 28. Lymphocytes from draining lymph nodes (LNs) were subjected to flow cytometry to analyze the frequency of CD4(+)CD25(+) Treg cells. CD4(+)CD25(+) Treg cells and CD4(+)CD25(-) T cells were separated by means of magnetic-assisted cell sorting and cocultured or crossover cultured for 3 days. Proliferation of CD4(+)CD25(-) T cells was measured using a modified MTT assay. The levels of IFN-gamma and IL-17 in the supernatants were determined by enzyme-linked immunosorbent assay. RESULTS: Clinical and histopathologic results showed a severe intraocular inflammation in the immunized mice. The frequency of CD4(+)Foxp3(+) T cells and CD4(+)CD25(+)Foxp3(+) T cells in the draining LN lymphocytes was increased on day 7, reached its peak on day 14, and maintained a high level up to day 42. CD4(+)CD25(+) Treg cells obtained from mice on days 14 and 28 after immunization showed a stronger inhibitory effect on the proliferation of CD4(+)CD25(-) T cells and the production of IFN-gamma by CD4(+)CD25(-) T cells compared with those obtained from control mice. CD4(+)CD25(+) Treg cells did not affect IL-17 production. Transfer of CD4(+)CD25(+) Treg cells obtained from EAU mice was able to suppress EAU induction by IRBP(161-180) that was not observed after transfer of cells from mice that had received CFA alone, suggesting antigen specificity of the Treg response. CONCLUSIONS: A significantly increased frequency and immunoregulatory action of CD4(+)CD25(+) Treg cells is associated with the development and regression of EAU, suggesting that CD4(+)CD25(+) Treg cells are induced during EAU and may be involved in its regression.

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis.

BACKGROUND: T-cell receptor (TCR) plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR V(beta) 8.3, an experimental autoimmune uveoretinitis (EAU)-associated gene, was able to prevent the disease. METHODS: EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund's adjuvant (CFA). The clinical and histological appearances were scored. Delayed type hypersensitivity (DTH) and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay (ELISA). Gene expression of TCR V(beta) 8.3 on CD(4)(+) T cells was examined by real time quantitative polymerase chain reaction (PCR). RESULTS: After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin (IL)-2 in aqueous humour, interferon (IFN)-gamma and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR V(beta) 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR V(beta) 8.3 gene was significantly reduced in the group of fourfold inoculations. CONCLUSION: Vaccination with the synthetic TCR V(beta) 8.3 peptide could remarkably inhibit the development of EAU.

[Therapeutic regimen in Vogt-Koyanagi-Harada syndrome].

OBJECTIVE: To compare the effectiveness of therapeutic regimen in Vogt-Koyanagi-Harada (VKH) syndrome and determine the reasonable regimen for different patients. METHODS: Data of 82 patients with VKH syndrome, coming from all over China and referred to Zhongshan Ophthalmic Center from January 1996 to December 2000 were retrospectively analyzed. Twenty-eight patients (56 eyes) with first attack of the intraocular inflammation were treated with oral prednisone for more than one year, whereas 54 patients (108 eyes) with recurrent episodes were treated with chlorambucil for more than one year. All patients were treated with a combination of these immunosuppressives with traditional Chinese medicine herbs, and followed up more than one year after systemic treatment. The previous treatment for these 54 patients was also analyzed in an attempt to compare these results with those presented here. RESULTS: Uveitis was completely controlled in 96.4% of the patients treated with oral prednisone, and all of these patients showed improved vision after treatment. A complete control of uveitis was achieved in 94.4% and improved vision was seen in 88.0% of the patients treated with chlorambucil. All of these 54 patients, although treated with longer but intermittent systemic corticosteroids before installation of chlorambucil, showed a chronic or recurrent uveitis and most cases had markedly decreased vision as compared with those treated by us with regular systemic corticosteroids. CONCLUSIONS: Intensive and prolonged systemic treatment with corticosteroids is recommended for the patients with first attack of VKH syndrome, where as regular treatment with chlorambucil is useful for control of chronic and recurrent uveitis seen in VKH syndrome. Traditional Chinese medicine herbs may be helpful in amelioration of uveitis and reduction of side effects of immunosuppressives.