Genetic, Cellular and Molecular Mechanisms in Autoimmunity to Retina

National Eye Institute

Investigators

Linked publications & trials

Abstract

1) MMUNITY AND AUTOIMMUNITY OF THE NEURORETINA The neuroretina is uniquely challenged to preserve vision while remaining protected from immune-mediated damage. Ocular immune privilege provides this balance, but the molecular basis of tolerance induction at the site of disease has remained poorly understood. We used single-cell transcriptomics to investigate the fate of retina-specific T cells encountering their antigen in the intraocular environment. We found that autoreactive T cells diverted into two distinct non-pathogenic fates: a fraction converted into Foxp3⁺ regulatory T cells while others adopted a stable anergic program【1】. These findings provide a molecular-level evidence that ocular immune privilege actively reprograms autoreactive T cells. The work fills a key gap in our understanding of local tolerance mechanisms in the retina and has implications for informing how to control tissue damage in autoimmune uveitis and potentially in other immune-privileged situations, such as tumor microenvironment. With the Menko laboratory, we demonstrated that immune cells adhering to the lens capsule during acute and resolution phases of EAU adopt immunoregulatory properties and interact with matrix molecules that determine whether inflammation resolves or persists【2,3】. In complementary work with the DeFranco group, checkpoints were identified in draining lymph nodes of a multigenic spontaneous uveitis model that govern whether autoreactive CD4⁺ T cells expand destructively or are restrained by Tregs (in revision, J. Immunol.). Together, these studies emphasize that tolerance in uveitis is established both at the target tissue and in regional immune compartments, a dual-level control system that helps preserve vision. To explore the contribution of ocular resident cells to immune responses within the eye, we applied AI-assisted multimodal analysis of publicly available datasets. This revealed previously unappreciated roles of Müller glial cells in shaping retinal autoimmunity. Once regarded as purely structural support cells, Müller cells were shown to undergo immune and metabolic changes during disease, including upregulation of antigen-presentation pathways, chemokine production, and glycolytic reprogramming, indicating activation. This could be interpreted as potentially sustaining pathogenic infiltrates (bioRxiv 2025.02.28.640907; PMID: 40093069 — in review. However, this interpretation contrasts with our earlier report that Müller cells can suppress activation and function of retina-specific lymphocytes in vitro (Science, 1987; PMID: 2956685). The contrast between inhibitory effects observed in the lab, and molecular evidence for activation of Müller cells in vivo, highlights the complexity of Müller cell–immune interactions and underscores the need to retest these questions with modern omics approaches to define their context-dependent roles in retinal autoimmunity. Lastly, we demonstrated that vitamin A, the precursor of retinoic acid that is involved in both immunity and vision, is required for the acquisition phase of CNS autoimmunity but dispensable for disease progression. This finding underscores the stage-specific metabolic requirements of T-cell responses and suggests that targeting vitamin A pathways may selectively influence disease initiation without impairing ongoing protective immunity. (bioRxiv 2025.05.18.654726; PMID: 40492202 —manuscript in preparation) 2) GUT MICROBIOME AND THE GUT–EYE AXIS We have previously demonstrated that the intestinal microbiome modulates ocular immunity in a spontaneous uveitis mouse model. We now tested whether human gut flora can transfer susceptibility to retinal autoimmunity. By reconstituting R161H mice with gut flora from healthy donors, we created humanized-flora (HuFl) mice. Similarly to specific-pathogen-free mouse flora, the humanized mice also developed spontaneous uveitis, albeit with somewhat lower average disease scores. Importantly, disease severity was linked to microbial composition, with enrichment of Verrucomicrobia, in particular Akkermansia, correlating with high disease scores, while Firmicutes enrichment associated with production of short-chain fatty acids and protection. This provides a direct demonstration that human microbiota can modulate susceptibility to retinal autoimmunity, offering a bridge between mouse models and human disease (manuscript in preparation). To further dissect host determinants of susceptibility, we generated a chromosome-scale genome assembly of the autoimmune-susceptible B10.RIII strain. This genomic resource will facilitate identification of disease loci and accelerate mechanistic studies on gene–environment interactions that underlie autoimmune uveitis. (bioRxiv 2025.05.16.654505; PMID: 40475550 — in preparation). 3) MUCOSAL IMMUNE RESPONSES AT THE OCULAR SURFACE The ocular surface is constantly exposed to commensals and environmental microbes, yet must maintain both barrier integrity and protection from infection. We previously identified Corynebacterium mastitidis (C. mast), as a commensal that provides protection from ocular surface pathogens through induction of IL-17–producing γδ T cells. We now studied what molecules stimulate the production of IL-17, and what host receptors sense the commensal. We identified trehalose monocorynomycolate (TMCM), a defined membrane component of C. mast, as molecule that stimulates IL-17 production by Vγ4 γδ T cells, at least in part by engaging the γδ TCR, and confers protection against pseudomonas infection. Thus, a single commensal-derived component, that can be synthetized in pure form, reproduces the protective function of the parent organism, providing a defined molecule that could be produced at a high level of purity to explore microbiome-inspired therapeutics. (bioRxiv 2025.03.17.643820; PMID: 40166223 — in final review, Immunity) In complementary work, we showed that Vγ6 γδ T cells rely on intrinsic TLR2 signaling to sustain IL-17A production via metabolic reprogramming. These results reveal an innate pathway by which the ocular surface harnesses commensal sensing to mobilize protective γδ-17 responses (Zhu W, Xu X, … Caspi RR, DOI: 10.1084/jem.20251046 J Exp Med, in press). Taken together, the TMCM and TLR2 studies delineate a two-arm defense system in which a defined lipid selectively activates Vγ4 cells, while broad pattern-recognition signaling sustains Vγ6 cells. Both converge on IL-17A as the effector cytokine, but their complementary modes of activation ensure robustness and redundancy in barrier protection. Beyond advancing basic understanding of mucosal immunology, these insights open opportunities for selective targeting of γδ T-cell subsets to enhance barrier immunity against ocular pathogens. We are also studying ocular surface responses to commensals in immunologically abnormal individuals, both mouse and human. In collaboration with Dr. Warren Strober's group (NIAID), who developed knock-in mice expressing a gain-of-function mutation in the NLRP3 inflammasome gene, and Dr. Raphaela Goldbach-Mansky, who treats patients with NLRP3-related diseases, we obtained evidence that an ocular surface commensal can elicit inflammation in an immunologically perturbed host, acting as a pathobiont. We are characterizing the local immune response and the ocular surface microbiome in the mouse model and patients with NLRP3 inflammasome mutations at the single-cell level (Siak, Mattapallil, St. Leger et al., in preparation). The findings will have implications for understanding and possibly for treating the characteristic ocular inflammation in patients with NLRP3-related diseases. 4) THERAPEUTIC MODULATION OF UVEITIS Understanding how to control pathogenic immune responses without impairing protective ones remains a major goal in translational ocular immunology. We investigated Laquinimod, an aryl hydrocarbon receptor agonist, as a potential therapeutic for autoimmune uveitis. In EAU, Laquinimod treatment inhibited disease during both the inductive and effector phases, acting through modulation of antigen-presenting cells. These results suggest that Laquinimod may be effective even when administered after disease onset, and provides a rationale for pursuing this agent in translational studies of T cell–mediated ocular inflammation. (bioRxiv 2025.05.20.654165; PMID: 40492200 — in preparation) 5) DEVELOPMENT OF TOOLS FOR AI-BASED MULTI-OMIC ANALYSIS The increasing complexity of immunologic datasets poses a challenge for discovery and interpretation. We addressed this by developing AI-based tools for multi-omics analysis. SCassist provides an AI-driven workflow that streamlines single-cell analysis and lowers the barrier to entry for high-dimensional data exploration【4】. IAN (Intelligent Analysis of Omics), in conjunction with SCAssist, integrates diverse datasets to automate pattern recognition and hypothesis generation (bioRxiv 2025.03.06.640921; PMID: 40161796 — in preparation). These platforms are already yielding biological insights, including potential the roles for Müller glia in retinal autoimmunity, described above. The integration of AI with experimental immunology provides a scalable strategy to accelerate discovery, maximize information gained from costly datasets, and prioritize targets for therapeutic development.