Insights gained from single-cell analysis of immune cells in tofacitinib treatment of Vogt-Koyanagi-Harada disease

Histone deacetylases facilitate Th17-cell differentiation and pathogenicity in autoimmune uveitis via CDK6/ID2 axis

INTRODUCTION

Autoimmune uveitis (AU) is a prevalent ocular autoimmune disease leading to significant visual impairment. However, underlying pathogenesis of AU required to develop more efficient therapy remain unclear.

METHODS

We isolated peripheral blood mononuclear cells (PBMCs) from AU patients and performed single-cell RNA sequencing (scRNA-seq). Besides, experimental autoimmune uveitis (EAU) model was established and treated with histone deacetylase inhibitor (HDACi) Belinostat or vehicle. We extracted immune cells from Blank, EAU, and HDACi-treated EAU mice and used scRNA-seq, flow cytometry, siRNA, specific inhibitors, and adoptive transfer experiments to explore the role of HDACs and its downstream potential molecular mechanisms in the immune response of EAU and AU.

RESULTS

We found highly expressed histone deacetylases (HDACs) family in AU patients and identified it as a key factor related to CD4+ effector T cell differentiation in the pathogenesis of AU. Our further studies showed that targeted inhibition of HDACs effectively alleviated EAU, restored its Th17/Treg balance, and reduced inflammatory gene expression, especially in CD4+ T cells. Post-HDACs inhibition, Treg proportions increased with enhanced immunomodulatory effects. Importantly, HDACs exhibited a positive promoting role on Th17 cells. Based on scRNA-seq screening and application of knock-down siRNAs and specific inhibitors in vitro and vivo, we identified CDK6 as a key downstream molecule regulated by HDAC1/3/6 through acetyl-histone H3/p53/p21 axis, which is involved in Th17 pathogenicity and EAU development. Additionally, HDACs-regulated CDK6 formed a positive loop with ID2, inducing PIM1 upregulation, promoting Th17 cell differentiation and pathogenicity, and correlates with AU progression.

CONCLUSION

Based on the screening of clinical samples and downstream molecular functional validation experiments, we revealed a driving role for HDACs and the HDACs-regulated CDK6/ID2 axis in Th17 cell differentiation and pathogenicity in AU, proposing a promising therapeutic strategy.

Therapeutic efficacy of tofacitinib in PDSAg-induced chronic experimental autoimmune uveitis in Wistar rat

PURPOSE

Tofacitinib, a small molecule pan-JAK inhibitor, targets key inflammatory pathways that play a pivotal role in the pathophysiology of uveitis. Its ability to inhibit multiple cytokine signaling pathways makes it a promising candidate for the treatment of ocular inflammation. This study aimed to investigate the effect of oral tofacitinib on peptide-derived S-antigen (PDSAg)-induced chronic experimental autoimmune uveitis (EAU) in rats.

MATERIALS AND METHODS

Nineteen albino Wistar rats were divided into five groups. Groups 1-3 (5 rats each) were immunized with 15 micrograms PDSAg to induce EAU; Group 2 received tofacitinib (5 mg/kg) by gavage twice daily. Group 3 received saline in the same manner as Group 2. Group 4 (2 rats) was a healthy control group. Group 5 (2 rats) received only tofacitinib. Uveitis development and treatment efficacy were evaluated using clinical scoring based on the the signs of anterior segment inflammation and histological scoring based on the deterioration of the retinal architectural structure.

RESULTS

Uveitis confirmed based on histological evidence was observed in all EAU groups (Groups 1-3) compared to the healthy control group (Group 4) (p < 0.001, Mann-Whitney U test). Tofacitinib significantly delayed the onset of uveitis in Group 2 when compared with Groups 1 and 3, which did not receive tofacitinib (p < 0.001, Mann-Whitney U test). Histological scores also showed a trend toward reduction (p = 0.393, Mann-Whitney U test).

CONCLUSIONS

Oral tofacitinib delayed uveitis onset and reduced clinical and histological findings, suggesting its potential as an alternative treatment for uveitis.

Comparative Efficacy of Interleukin-7 and -15 Blockade in Alleviating Experimental Chronic Uveitis and Suppressing Pathogenic Memory CD4+ T Cells

Purpose

We have previously demonstrated the pathogenic function of memory CD4+ T cells, which express IL-7 receptor (IL-7R) and IL-15R, in experimental chronic autoimmune uveitis (CAU). Here, we aimed to compare the therapeutic efficacy of blocking IL-7 or IL-15 in CAU.

Methods

C57BL/6J mice were induced for CAU, then intraperitoneally injected with an anti-IL-7 antibody (Ab), an anti-IL-15 Ab, or an IgG control for 2 weeks. Disease was evaluated by weekly fundoscopy, optical coherence tomography (OCT), and full-field electroretinography for four weeks from the initiation of treatment. At week 4, retina and cervical lymph nodes (CLN) were collected for flow cytometry analysis of T-cell response.

Results

The anti-IL-7 Ab led to progressively reduced retinal infiltration and structural damage, with rapid recovery of retinal function. The anti-IL-15 Ab resulted in moderately reduced retinal infiltration and structural damage, along with a delayed, partial functional improvement. Compared to the control group, the anti-IL-7 Ab group exhibited significantly reduced disease scores from baseline on fundoscopy and OCT at week 4, and substantially improved dark-adapted (DA) a-wave and light-adapted b-wave responses at week 2; although the anti-IL-15 Ab group showed significantly improved disease from baseline only on OCT and increased DA b-waves at week 4. Both treatments effectively depleted the retinal infiltrating T cells and reduced memory Th17 cells in the CLN.

Conclusions

Our proof-of-concept study demonstrates that blocking IL-7 or IL-15 leads to specific depletion of the uveitogenic memory CD4+ T cells and disruption of disease chronicity in uveitis.

Clinical and Transcriptional Profiles Reveal the Treatment Effect of Adalimumab in Patients with Initial-Onset and Recurrent Vogt-Koyanagi-Harada Disease

PURPOSE

We aimed to evaluate adalimumab efficacy in patients with initial-onset or recurrent Vogt-Koyanagi-Harada (VKH) syndrome.

METHODS

A retrospective clinical study was performed to examine the therapeutic effect of adalimumab in 22 VKH patients,16 with initial-onset and six with recurrent VKH. Another 22 patients with initial-onset VKH who did not receive adalimumab were included as controls. The main observational parameters included the central macular thickness (CMT), subfoveal choroidal thickness (SCT), best-corrected visual acuity (BCVA), anterior chamber cell grade (ACC), glucocorticoid dose (GCD), and the development of sunset glow fundus. MRNA sequencing was used to profile the tumor necrosis factor (TNF)-α pathway in peripheral blood mononuclear cells obtained from nine patients with initial-onset VKH disease, six patients with recurrent VKH, and eight healthy controls.

RESULTS

In the initial-onset group, adalimumab therapy significantly improved the BCVA, CMT, SCT, and ACC. Furthermore, adalimumab significantly decreased GCD in patients with initial-onset. In patients with recurrent VKH, the SCT significantly improved after adalimumab treatment, but no significant changes in BCVA, CMT, and ACC were observed. All six patients experienced relapse during follow-up. The TNF-α pathway exhibited a significant increase in initial-onset VKH when compared with that in both healthy controls and recurrent patients. Conversely, it was suppressed in recurrent VKH when compared with that in the initial-onset or healthy control groups.

CONCLUSIONS

In patients with initial-onset VKH, adalimumab effectively reduces glucocorticoid dependence. However, adalimumab may not be effective for preventing relapse or providing long-term inflammation relief in patients with recurrent VKH.

Irradiated umbilical cord mesenchymal stem cell-coated high oxygen-permeable hydrogel lenses inhibit corneal inflammation and neovascularization after corneal alkali burns

Corneal alkali burns can cause persistent inflammation and corneal neovascularization. In this study, we divided corneal alkali burned rabbits into the untreated group, the blank lens group, the radiation-treated umbilical cord mesenchymal stem cells (UCMSC) lens group, and the UCMSC I.V. group, and then measured corneal inflammation, neovascularization and corneal injury repair via slit lamp microscopy, captured anterior segment optical coherence tomography (AS-OCT), and performed hematoxylin-eosin staining. Compared with those in the other experimental groups, radiation-treated UCMSC lenses significantly decreased inflammatory index (IF) scores, areas of corneal blood vessels and corneal epithelial injury. The expression of interleukin (IL)-17 in corneas treated with radiation-treated UCMSC lenses was lower than that in corneas treated with blank lenses, and radiation-treated UCMSC lenses exhibited greater expression of IL-4 and signal transducer and activator of transcription 1 (STAT1), while the expression of cluster of differentiation-3G (CD3G), a linker for the activation of T cells (LAT), IL-6, IL-1B, CC chemokine receptor 6 (CCR6) and IL-23 exhibited the opposite effects (all P < 0.05). Our findings demonstrated that irradiated UCMSC-coated high oxygen-permeable hydrogel lenses on the ocular surface inhibited corneal angiogenesis and inflammation after corneal alkaline burns. The downregulation of Th17 cell differentiation might be responsible for these effects.

Classification of Peripheral Blood Leukocyte Phenotypes and Serum Cytokines in Vogt-Koyanagi-Harada Disease before and after Glucocorticoid Therapy

Vogt-Koyanagi-Harada disease (VKH) is an autoimmune disease, and glucocorticoid therapy (GC) is widely used for VKH. We provided a profile of leukocyte populations and serum cytokines in VKH patients under GC. A prospective observational study was conducted on three treatment-naïve VKH patients. Peripheral blood samples were collected from the patients before GC (VKH-acute) and after 6 months (VKH-remission), and healthy individuals were used as controls. Proportions of 37-type leukocytes and levels of 27-kind cytokines were measured by mass cytometry and multiplex bead analysis. Property similarity was analyzed using hierarchical cluster analysis. The leukocytes and cytokines were broadly classified into four and three clusters: (1) a cluster with high intensity in VKH-acute consisting of B cells, Th2-like, Th17-like, basophils, and IL-7 and IP-10; (2) a cluster with high intensity in VKH-remission composed of monocytes, neutrophils, IL-4, and TNFα; in leukocytes, (3) a cluster with low intensity in VKH-acute and -remission consisting of CD8+ T cells, Th1-like, and NKT cells; (4) a cluster with low intensity in VKH-remission composed of NK cells, Tregs, and DCs; and in cytokines, (5) a cluster with high intensities in VKH-acute and -remission comprising G-CSF, MCP-1, eotaxin, and IL-17A. These findings suggest that inflammatory composition in blood during the acute phase of VKH represents complex hyperimmune responses dominantly driven by Th and B cells.

Progesterone attenuates Th17-cell pathogenicity in autoimmune uveitis via Id2/Pim1 axis

BACKGROUND

Autoimmune uveitis (AU) is the most common ophthalmic autoimmune disease (AD) and is characterized by a complex etiology, high morbidity, and high rate of blindness. AU remission has been observed in pregnant female patients. However, the effects of progesterone (PRG), a critical hormone for reproduction, on the treatment of AU and the regulatory mechanisms remain unclear.

METHODS

To this end, we established experimental autoimmune uveitis (EAU) animal models and constructed a high-dimensional immune atlas of EAU-model mice undergoing PRG treatment to explore the underlying therapeutic mechanisms of PRG using single-cell RNA sequencing.

RESULTS

We found that PRG ameliorated retinal lesions and inflammatory infiltration in EAU-model mice. Further single-cell analysis indicated that PRG reversed the EAU-induced expression of inflammatory genes (AP-1 family, S100a family, and Cxcr4) and pathological processes related to inflammatory cell migration, activation, and differentiation. Notably, PRG was found to regulate the Th17/Treg imbalance by increasing the reduced regulatory functional mediators of Tregs and diminishing the overactivation of pathological Th17 cells. Moreover, the Id2/Pim1 axis, IL-23/Th17/GM-CSF signaling, and enhanced Th17 pathogenicity during EAU were reversed by PRG treatment, resulting in the alleviation of EAU inflammation and treatment of AD.

CONCLUSIONS

Our study provides a comprehensive single-cell map of the immunomodulatory effects of PRG therapy on EAU and elaborates on the possible therapeutic mechanisms, providing novel insights into its application for treating autoimmune diseases.