Beneficial mechanisms of dimethyl fumarate in autoimmune uveitis: insights from single-cell RNA sequencing.

BACKGROUND: Dimethyl fumarate (DMF) is a fumaric acid ester that exhibits immunoregulatory and anti-inflammatory properties. However, the function of DMF in autoimmune uveitis (AU) is incompletely understood, and studies comprehensively exploring the impact of DMF on immune cells are still lacking. METHODS: To explore the function of DMF in uveitis and its underlying mechanisms, we conducted single-cell RNA sequencing (scRNA-seq) on the cervical draining lymph node (CDLN) cells of normal, experimental autoimmune uveitis (EAU), and DMF-treated EAU mice. Additionally, we integrated scRNA-seq data of the retina and CDLNs to identify the potential impact of DMF on ocular immune cell infiltration. Flow cytometry was conducted to verify the potential target molecules of DMF. RESULTS: Our study showed that DMF treatment effectively ameliorated EAU symptoms. The proportional and transcriptional alterations in each immune cell type during EAU were reversed by DMF treatment. Bioinformatics analysis in our study indicated that the enhanced expression of Pim1 and Cxcr4 in EAU was reversed by DMF treatment. Further experiments demonstrated that DMF restored the balance between effector T (Teff) /regulatory T (Treg) cells through inhibiting the pathway of PIM1-protein kinase B (AKT)-Forkhead box O1 (FOXO1). By incorporating the scRNA-seq data of the retina from EAU mice into analysis, our study identified that T cells highly expressing Pim1 and Cxcr4 were enriched in the retina. DMF repressed the ocular infiltration of Teff cells, and this effect might depend on its inhibition of PIM1 and CXCR4 expression. Additionally, our study indicated that DMF might reduce the proportion of plasma cells by inhibiting PIM1 expression in B cells. CONCLUSIONS: DMF effectively attenuated EAU symptoms. During EAU, DMF reversed the Teff/Treg cell imbalance and suppressed the ocular infiltration of Teff cells by inhibiting PIM1 and CXCR4 expression. Thus, DMF may act as a new drug option for the treatment of AU.

Single-cell sequencing of the retina shows that LDHA regulates pathogenesis of autoimmune uveitis.

Autoimmune uveitis (AU) is a severe disorder causing poor vision and blindness. However, the cellular dynamics and pathogenic mechanisms underlying retinal injury in uveitis remain unclear. In this study, single-cell RNA sequencing of the retina and cervical draining lymph nodes in experimental autoimmune uveitis mice was conducted to identify the cellular spatiotemporal dynamics and upregulation of the glycolysis-related gene LDHA. Suppression of LDHA can rescue the imbalance of T effector (Teff) cells/T regulator (Treg) cells under inflammation via downregulation of the glycolysis-PI3K signaling circuit and inhibition of the migration of CXCR4+ Teff cells towards retinal tissue. Furthermore, LDHA and CXCR4 are upregulated in the peripheral blood mononuclear cells of Vogt-Koyanagi-Harada patients. The LDHA inhibitor suppresses CD4+ T cell proliferation in humans. Therefore, our data indicate that the autoimmune environment of uveitis regulates Teff cell accumulation in the retina via glycolysis-associated LDHA. Modulation of this target may provide a novel therapeutic strategy for treating AU.

Mechanism of fibrosis inhibition in laser induced choroidal neovascularization by doxycycline.

To explore the mechanisms underlying doxycycline suppression of fibrosis in laser-induced choroidal neovascularization (LCNV), C57BL/6J male mice (aged from 6 to 8 weeks) received intraperitoneal injections of PBS/doxycycline solution from one day before laser injury until they were sacrificed. Leakage was assessed by FA, and CNV (stained by IB4) or fibrosis (stained by collagen type I) size was measured. The percentage of Pan-keratin+α-SMA+ cells was counted in the eyes' cryostat sections by immunohistochemistry. qPCR was used to measure the mRNA of markers of pan-macrophages, M1 and M2-type macrophages (M1 and M2), markers of EMT, and markers in the downstream of STAT6 signaling. Western blotting was used to analyze the expression of Arg-1, α-SMA, E-cadherin, pSTAT6 and STAT6. Our data showed that doxycycline inhibited leakage from CNV, areas of CNV on day 7 and day 14, and suppressed fibrosis, and the ratio of fibrotic/angiogenic areas during day 7 to day 35. We also showed attenuation of EMT in the doxycycline group. The percentage of Pan-keratin+α-SMA+ cells was lower in the doxycycline group than in the control group. The mRNA and protein levels of mesenchymal markers were downregulated in the doxycycline group, while the epithelial marker was upregulated. In addition, our data showed that the protein expression of Arg-1, the mRNA expression of M1 and M2-markers, were both inhibited by doxycycline, while the level of pan-macrophages (f4/80) showed no significant difference in two groups. Finally, our results showed that doxycycline was able to modulate the STAT6 signaling in transcript and protein levels. Accordingly, we suggested that the mechanism of doxycycline-mediated inhibition of fibrosis in CNV occurs through the STAT6 pathway.

The Efficacy of Adalimumab in Children with Chronic Non-infectious Posterior Uveitis and Panuveitis: A Retrospective Cohort Study.

INTRODUCTION: This study aimed to assess the efficacy and safety of adalimumab in pediatric patients with chronic non-infectious posterior uveitis and panuveitis (not associated with juvenile idiopathic arthritis). METHODS: The medical records of children (< 18 years old) with chronic non-infectious posterior uveitis and panuveitis were collected and analyzed in this retrospective cohort study. Children were allocated to a conventional adalimumab-free treatment (CT) or adalimumab (ADA) group based on whether they additionally received adalimumab. RESULTS: In total, 69 children (138 eyes) were included, with 21 (42 eyes) and 48 (96 eyes) in the CT and ADA groups, respectively. During the average follow-up period of 24 months, the improvement in all ocular parameters (best-corrected visual acuity, intraocular inflammation, fluorescein angiography score) was better in the ADA group than in the CT group, except for changes in central macular thickness, which did not significantly differ between the groups. The mean time of first alleviation, which was after 1.03 ± 0.12 months of therapy, was earlier in the ADA group than in the CT group (2.30 ± 0.46 months). In the ADA group, 90.6% of children had remission within 3 months, and 47.9% had no relapse during follow-up. Cough and cold were the most common adverse events in the ADA group; however, the number of adverse events was similar between both the groups. CONCLUSIONS: Adalimumab was effective in the treatment of chronic noninfectious posterior uveitis and panuveitis in pediatric patients, and disease inactivity was accomplished in the majority of the patients, thereby improving visual outcomes and maintaining disease stability. Adverse events were limited and tolerable.

Successful Remission with Upadacitinib in Two Patients with Anti-TNF-Refractory Macular Edema Associated with Behçet's Uveitis.

PURPOSE: Behçet's syndrome (BS) is a chronic inflammatory disease affecting the small and large vessels of the venous and arterial systems and is characterized by recurrent oral and genital ulcers. Uveitis represents the most typical ocular manifestation and completes the triple symptom complex originally described. Recognized treatments for Behçet's uveitis (BU) include systemic glucocorticoids and immunosuppressive agents. No study has reported on the use of upadacitinib for BS with panuveitis. Herein, we report the use of upadacitinib in two patients with BU suffering from macular edema and persistent inflammation, which was refractory to systemic glucocorticoids and immunosuppressive agents. METHODS: We retrospectively followed-up two cases, including an adolescent girl and a man in his thirties, with a 2- and 10-year history of BS, respectively. RESULTS: Upadacitinib successfully treated BU, leading to improved visual acuity, controlled intraocular inflammation, and the disappearance of macular edema in both patients. The patients in this study were either recalcitrant to or intolerant to conventional therapy and adalimumab. Only the female patient revealed a mildly abnormal blood picture and slight transaminitis after 6 months of upadacitinib administration. However, no serious adverse events were reported in either of the two patients during follow-up. CONCLUSION: Upadacitinib can be considered an important future option for managing recurrent and recalcitrant cases of BU, especially in those with chronic ocular inflammation and macular edema, which are refractory to conventional therapies.

Single-Cell transcriptomes of immune cells provide insights into the therapeutic effects of mycophenolate mofetil on autoimmune uveitis.

Mycophenolate mofetil (MMF) is an immunosuppressive agent widely applied in various autoimmune diseases, including autoimmune uveitis, a sight-threatening autoimmune disease mainly affecting the eyes. However, the mechanisms of action are not comprehensively understood. To investigate the potential impact of MMF on uveitis, we generated single-cell RNA sequence data from normal, experimental autoimmune uveitis (EAU) and MMF-treated EAU mice. We observed that some EAU-induced transcriptional changes were reversed by MMF treatment. Transcriptional data indicated that MMF may have a general inhibitory effect on the activation of immune cells during EAU. Each immune cell type showed a different response to MMF treatment. Pseudotime analysis showed that MMF treatment partly reversed the increased differentiation tendency from naïve to effector phenotypes of T and B cells in EAU. The reduced proportion of T-helper (Th)1 and T-helper (Th)17 cells after MMF treatment was confirmed using flow cytometry. MMF treatment downregulated the EAU-associated upregulation of several molecules (such as Cebpd, Pim1, Furin, Bhlhe40, and Hif1a) that promote pathogenic cytokine production by T helper (Th)-1 and Th17 cells. Abnormally enhanced immunoglobulin production, antigen processing, and presentation ability of B cells may also be inhibited by MMF treatment. In addition to T and B cells, MMF treatment countered EAU-induced transcriptional changes in other immune cells to different degrees. Overall, our findings provide novel insights into the mechanisms underlying MMF treatment and indicate that the therapeutic effect of MMF is not driven by a single molecule.

Identification of Hif1α as a Potential Participant in Autoimmune Uveitis Pathogenesis Using Single-Cell Transcriptome Analysis.

Purpose: This study purposed to depict the transcriptional changes associated with autoimmune uveitis (AU) pathogenesis and identify potential therapeutic targets of this disease. Methods: An experimental AU (EAU) model was established with retina antigen and adjuvants. An EAU control group was established with adjuvant only to eliminate nonspecific effects. We conducted single-cell RNA sequencing (scRNA-seq) on cervical draining lymph node cells of EAU, EAU control, and normal mice to identify the EAU-associated transcriptional changes and the potential pathogenic molecules. Subsequent flow cytometry, adoptive transfer experiment, scRNA-seq analysis of human uveitis, and proliferation assessment were conducted to verify the function of the interested molecule in uveitis. Results: The scRNA-seq data suggested that hypoxia-inducible factor 1 alpha (Hif1α) may participate in EAU pathogenesis via regulating T helper (Th)-17, Th1, and regulatory T cells. Hif1α inhibition alleviated EAU symptoms and regulated Th17, Th1, and regulatory T cell proportions. CD4+ T cells with repressed Hif1α expression failed to transfer EAU to naïve mice. In Vogt-Koyanagi-Harada disease, which is a human uveitis, Hif1α was also increased in CD4+ T cells and regulated their proliferation. Conclusions: The results indicate that Hif1α may participate in AU pathogenesis and are, thus, a potential therapeutic target.

Adalimumab plus Conventional Therapy versus Conventional Therapy in Refractory Non-Infectious Scleritis.

Long-term systemic glucocorticoids and non-specific immunosuppressants remain the mainstay of treatment for refractory scleritis, and result in serious side-effects and repeated inflammation flares. To assess the efficacy and safety of additional adalimumab, patients diagnosed with refractory non-infectious scleritis were enrolled. They were assigned to the conventional-therapy (CT, using systemic glucocorticoids and other immunosuppressants) group or the adalimumab-plus-conventional-therapy (ACT) group according to the treatments they received. The primary outcome was time to achieve sustained remission, assessed by a reduction in modified McCluskey's scleritis scores. Other outcomes included changes in McCluskey's scores, scleritis flares, best-corrected visual acuity, and spared glucocorticoid dosage. Patients in the ACT group achieved faster remission than those in the CT group, as the median periods before remission were 4 months vs. 2.5 months (p = 0.016). Scleritis flares occurred in 11/11 eyes in the CT group and 5/12 eyes in the ACT group (p = 0.005). Successful glucocorticoid sparing was realized in both groups, but the ACT group made it faster. No severe adverse events were observed. Data suggest that adalimumab plus conventional therapy could shorten the time to remission, reduce disease flares, and accelerate glucocorticoid withdrawal compared with conventional therapy alone.

Mutation Spectrum of the LRP5, NDP, and TSPAN12 Genes in Chinese Patients With Familial Exudative Vitreoretinopathy.

Purpose: LRP5, NDP, and TSPAN12 are known to be associated with familial exudative vitreoretinopathy (FEVR). In this study, a comprehensive mutation screening for the three genes was performed in patients with a clinical diagnosis of FEVR in Han Chinese. Methods: Genomic DNA and clinical data were collected from 100 probands and their family members. Sanger sequencing was performed to screen for LRP5, NDP, and TSPAN12 mutations and phenotype-genotype correlation was analyzed. Results: There were 23 causative mutations identified in 23 unrelated probands (10/23 in LRP5, 8/23 in TSPAN12, and 5/23 in NDP). Apart from NDP mutations, only two LRP5 mutations inherited in an autosomal recessive manner. Among the 23 causative mutations, 13 were novel variants (4/10 in LRP5, 6/8 in TSPAN12, and 3/5 in NDP). According to the modified classification system, statistical significance was observed in the distribution of mutated genes (P = 0.049). None of the causative mutations was found in group I FEVR. Probands with LRP5 or NDP mutations were mainly categorized into group III and IV, TSPAN12 mutations were mainly observed in probands with group IV and V FEVR. Conclusions: The detection rate for mutations in the three known genes was 23%. Mutations in LRP5 and TSPAN12 were more frequent, accounting for 10% and 8%, respectively. The NDP mutations were only identified in 6% in this cohort. There were 13 novel variants found, which provided a deeper understanding of this disease. Potential phenotype-genotype correlation was observed in the modified system. TSPAN12 mutations might lead to the most severe phenotype.