Uveitis: Molecular Pathogenesis and Emerging Therapies

Pathogenesis and targets in uveitis

Uveitis is the most common ocular finding in systemic rheumatic diseases. It is a potentially sight threatening disease seen on its own or in association with systemic rheumatic diseases. Whilst significant advances have been made with biological and small molecular therapies for conditions such as rheumatoid arthritis (RA), ankylosing spondylisitis (AS), juvenile idiopathic arthritis (JIA) and psoriatic arthritis (PsA), the evidence base for managing the ocular complications from these diseases, particularly uveitis, is still limited.

Nano-based drug delivery systems for the treatment of non-infectious uveitis

Background

Uveitis is one of the most prevalent causes of global visual impairment. The current approaches to treating non-infectious uveitis (NIU) involve the utilization of corticosteroids, immunosuppressant and biologics agents. Nevertheless, the intricate ocular anatomy barriers and adverse side effects of the drugs pose significant obstacles to effective treatment outcomes.

Main text

To improve drug bioavailability and therapeutic outcomes for NIU while minimize side effects, researchers are committed to developing novel nano-based drug delivery systems (DDS), which have the capacity to achieve targeted delivery, increase bioavailability, achieve sustained release, reduce side effects and improve therapeutic effects. Thus, DDS based on nanotechnology, including liposome, dendrimer, hydrogels, nanoparticles, nanomicelles, nanosuspensions and nanoemulsions have emerged as promising alternatives to conventional ocular delivery methods for the management of NIU.

Conclusions

In this review, we summarize the current therapeutic challenges faced by NIU and describe various nano-based intraocular DDS involved in the treatment of NIU. It is concluded that nano-based DDS is an appealing approach to addressing the unmet needs for the treatment of NIU.

B-cell depletion therapy reduces retinal inflammation in experimental autoimmune uveoretinitis

OBJECTIVE

Non-infectious uveitis (NIU) is recognized as a group of autoimmune sight-threatening disorders with complex pathogenesis. This study aims to analyze the pathogenic role of B cells in NIU and evaluate the effectiveness of B cell depletion therapy in experimental autoimmune uveoretinitis (EAU) mice.

METHODS

We performed high throughput transcriptome sequence on peripheral blood samples from healthy individuals (n = 6) and NIU patients (n = 12), and reanalyzed single-cell RNA transcriptome data of aqueous humor in NIU patients (n = 5). Female C57BL/6 J mice were induced the EAU model through immunization with the IRBP651-670 peptide. B cell depletion was performed via intravitreal injection of anti-CD20 antibody on day 7 and mice were executed on day 14 following antigen administration. Clinical symptoms were assessed by fundus photography and fundus fluorescein angiography. Pathological sections were analyzed using immunohistochemistry and immunofluorescence. Serum immunoglobulins and inflammatory factors were detected by ELISA.

RESULTS

Transcriptome sequencing and single-cell RNA analysis revealed strong B cell immune responses in both peripheral blood and aqueous humor of NIU patients. Intravitreal injection of anti-CD20 antibody partially reduces B cell numbers, suppresses T cell proliferation in CLNs, and decreases serum IgG and inflammatory cytokines level, which collectively alleviate clinical symptoms and mitigate retinal inflammation. Significant differences in BCR sequences were observed between the NIU groups and healthy controls.

CONCLUSION

B-cell depletion therapy may offer a novel strategy for the treatment of NIU and identifying specific BCR sequences provides a potential target for both therapeutic intervention and disease monitoring.

Analysis of Serum microRNAs During the Development of Experimental Autoimmune Uveoretinitis in Rats

PURPOSE

To investigate alterations in circulating microRNAs (miRNAs) in the development of experimental autoimmune uveoretinitis (EAU) in rats.

METHODS

Lewis rats were immunized with interphotoreceptor retinoid binding protein (IRBP) peptide (R14) and EAU clinical scores were assessed on day 0 (baseline), and days 7, 14, and 21 after immunization. Total RNA was isolated from serum at the same timepoints and used for microarray analysis.

RESULTS

The clinical score of EAU peaked on day 14 and decreased on day 21. Hierarchical cluster analysis and principal component analysis (PCA) of serum miRNA expression displayed distinctly different miRNA profiles between baseline and days 7, 14, and 21 after immunization. Microarray analysis revealed significantly increased expression of 5 (day 7), 9 (day 14), and 10 (day 21) miRNAs, and significantly decreased expression of 19 (day 7), 20 (day 14), and 19 (day 21) miRNAs compared to baseline. Of note, the expression of miRNA-146a-5p, known to be involved in EAU, and miRNA-150-5p was significantly elevated on days 14 and 21. Bioinformatics analysis revealed that mucin type O-glycan biosynthesis and cell adhesion molecules were major pathways affected during the development of EAU.

CONCLUSIONS

Hierarchical cluster analysis and PCA showed distinctly different miRNA profiles at baseline versus after IRBP immunization. Upregulation of serum miRNA-146a-5p and miRNA-150-5p was observed in the effector and resolution phases of EAU. Analysis of circulating miRNAs may help to delineate systemic epigenetic changes occurring in the development of EAU, and may lead to new insights in our understanding of human uveitis.

Integrative immunology identified interferome signatures in uveitis and systemic disease-associated uveitis

Introduction

Uveitis accounts for up to 25% of global legal blindness and involves intraocular inflammation, classifed as infectious or non-infectious. Its complex pathophysiology includes dysregulated cytokines, particularly interferons (IFNs). However, the global signature of type I, II, and III interferon-regulated genes (Interferome) remains largely uncharacterized in uveitis.

Methods

In this study, we conducted an integrative systems biology analysis of blood transcriptome data from 169 non-infectious uveitis patients (56 isolated uveitis, 113 systemic disease-associated uveitis) and 82 healthy controls.

Results

Modular co-expression analysis identified distinct cytokine signaling networks, emphasizing interleukin and interferon pathways. A meta-analysis revealed 110 differentially expressed genes (metaDEGs) in isolated uveitis and 91 in systemic disease-associated uveitis, predominantly linked to immune responses. The Interferome database confirmed a predominance of type I and II IFN signatures in both groups. Pathway enrichment analysis highlighted inflammatory responses, including cytokine production (IL-8, IL1-β, IFN-γ, β, and α) and toll-like receptor signaling (TLR4, TLR7, TLR8, CD180). Principal component analysis emphasized the IFN signature's discriminative power, particularly in systemic disease-associated uveitis. Machine learning identified IFN-associated genes as robust predictors, while linear discriminant analysis pinpointed CCR2, CD180, GAPT, and PTGS2 as key risk factors in isolated uveitis and CA1, SIAH2, and PGS in systemic disease-associated uveitis.

Conclusion

These findings highlight IFN-driven imune dysregulation and potential molecular targets for precision therapies in uveitis.

Do the monocyte-derived dendritic cells exert a pivotal role in the early onset of experimental autoimmune uveitis?

BACKGROUND

Eyes are recognized as immunological privileged site. However, the onset of autoimmune uveitis (AU) prompts an influx of dendritic cells (DCs) into the retinas, tasked with presenting auto-antigens, thereby exacerbating the inflammatory response. Monocyte-derived DCs (moDCs) implicated in various autoimmune disorders, but their specific involvement in AU remains unclear. This study aims to investigate the constitution and dynamics of retinal DCs subsequent to the induction of experimental autoimmune uveitis (EAU).

METHODS

In our study, an EAU model was established in C57BL/6J mice, and prednisolone acetate (PA) eye drops were administrated unilaterally to the right eye from 5 days post-immunization (dpi). The infiltration of Gr-1+CD115+CD11c-MHC-II- cells (monocytes), Gr-1+CD115+CD11c+MHC-II+ cells (moDCs) and Gr-1-CD115-CD11c+MHC-II+ cells (conventional dendritic cells, cDCs) within retina were detected by flow cytometry and immunofluorescence stain at 7, 10, 13, and 16 dpi. Additionally, the protein expression and mRNA expression of pivotal cytokines associated with moDCs and inflammation were analysed by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), respectively.

RESULTS

Our findings unveiled a notable rise in moDCs infiltration and differentiation from 7 to 13 dpi. The administration of PA eye drops did not yield a significant variance in either the quantity or the differentiation rate of moDCs. Throughout the initial stages of EAU, the expression of GM-CSF remained consistent, while TGF-β1 exhibited a sustained increase until 13 dpi in the control group and until 10 dpi following PA treatment. Anti-inflammatory cytokines Il-10 and Il-4 displayed no significant increase until 16 dpi after PA administration.

CONCLUSIONS

Our results indicate that moDCs exhibited an earlier and more substantial infiltration into the inflamed retina compared to cDCs. This heightened presence of moDCs appeared to play a dominant role in the presentation of auto-antigens during the initial stages of EAU, consequently contributing to the exaggerated autoimmune response within the ocular milieu. The administration of PA exhibited no discernible impact on either the differentiation or the infiltration of moDCs.

IL-6/IL-12 superfamily of cytokines and regulatory lymphocytes play critical roles in the etiology and suppression of CNS autoimmune diseases

Cytokines influence cell-fate decisions of naïve lymphocytes and determine outcome of immune responses by transducing signals that regulate the initiation, intensity and duration of immune responses. However, aberrant regulation of physiological levels of cytokines contribute to the development of autoimmune and other inflammatory diseases. The Interleukin 6 (IL-6)/IL-12 superfamily of cytokines have a profound influence on all aspects of host immunity and our focus in this review is on the signaling pathways that mediate their functions, with emphasis on how this enigmatic family of cytokines promote or suppress inflammation depending on the physiological context. We also describe regulatory lymphocyte populations that suppress neuroinflammatory diseases by producing cytokines, such as IL-27 (i27-Breg) or IL-35 (i35-Breg and iTR35). We conclude with emerging immunotherapies like STAT-specific Nanobodies, Exosomes and Breg therapy that ameliorate CNS autoimmune diseases in preclinical studies.

Association between axial length and uveitis

PURPOSE

Multiple studies have examined the association between myopia and various ocular diseases, but there is no clinical report of the relationship between myopia and uveitis. This study aimed to elucidate the relationship between myopia and uveitis by comparing axial lengths (AL) of uveitis patients with control individuals.

METHODS

This study included 1052 eyes (663 patients; 288 males, 375 females; median age 56.0 years) with uveitis referred to Tokyo Medical University Hospital. Controls were 738 eyes with cataract but no other ocular diseases. AL was measured by IOLMaster or conventional A-mode ultrasound system. Uveitis eyes were grouped into various types of non-infectious uveitis, infectious uveitis, and unidentified uveitis. Median AL of each uveitis group was compared with control group using Mann-Whitney U-test, and also compared with adjustment for age and sex using multiple regression analysis. Binary logistic analysis was performed to examine whether AL plays a role in the risk of developing uveitis.

RESULTS

Of 1052 eyes, 808 eyes (76.8%) were diagnosed with non-infectious uveitis [sarcoidosis (176 eyes, 16.7%), Vogt-Koyanagi-Harada disease (122 eyes, 11.6%), Behçet's disease (130 eyes, 12.4%), and others (380 eyes, 36.1%)], 146 eyes (13.9%) with infectious uveitis, and 98 eyes (9.3%) with unidentified uveitis. Median AL in all uveitis eyes was significantly shorter than in control eyes (23.73 vs 24.31 mm, p < 0.001 unadjusted), and AL remained significantly shorter in uveitis than in control after age- and sex-adjustment (p < 0.001). Median AL was significantly shorter in non-infectious uveitis (23.72 mm) and in infectious uveitis (23.99 mm) compared to controls (p < 0.001 and < 0.05, respectively), and was significantly shorter in non-infectious uveitis than in infectious uveitis (p < 0.05). Each millimeter decrease in AL was associated with 1.266-fold increase in unadjusted risk [odds ratio (OR), 1.266; 95% confidence interval (CI), 1.196-1.341; p < 0.001) and 1.446-fold in age- and sex-adjusted risk (OR, 1.446; 95% CI, 1.349-1.549; p < 0.001) of developing uveitis.

CONCLUSION

Median AL of uveitis eyes with infectious or non-infectious etiologies was significantly shorter than that in control eyes, suggesting an increased risk of developing uveitis in eyes with shorter AL. This feature should be considered when exploring new pathogenetic mechanisms of uveitis.

KEY MESSAGES

What is known Shorter axial length may be associated with the pathogenesis of central serous chorioretinopathy and increased risk of early age-related macular degeneration. What is new Here we assessed the relationship between myopia and uveitis by comparing axial lengths of uveitis patients. Median axial length in all uveitis eyes was significantly shorter than in control eyes, and axial length remained significantly shorter in uveitis than in control after age- and sex-adjustment. Each millimeter decrease in axial length was associated with 1.266-fold increase in unadjusted risk and 1.446-fold in age- and sex-adjusted risk of developing uveitis.

RNA methylation homeostasis in ocular diseases: All eyes on Me

RNA methylation is a pivotal epigenetic modification that adjusts various aspects of RNA biology, including nuclear transport, stability, and the efficiency of translation for specific RNA candidates. The methylation of RNA involves the addition of methyl groups to specific bases and can occur at different sites, resulting in distinct forms, such as N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), and 7-methylguanosine (m7G). Maintaining an optimal equilibrium of RNA methylation is crucial for fundamental cellular activities such as cell survival, proliferation, and migration. The balance of RNA methylation is linked to various pathophysiological conditions, including senescence, cancer development, stress responses, and blood vessel formation, all of which are pivotal for comprehending a spectrum of eye diseases. Recent findings have highlighted the significant role of diverse RNA methylation patterns in ophthalmological conditions such as age-related macular degeneration, diabetic retinopathy, cataracts, glaucoma, uveitis, retinoblastoma, uveal melanoma, thyroid eye disease, and myopia, which are critical for vision health. This thorough review endeavors to dissect the influence of RNA methylation on common and vision-impairing ocular disorders. It explores the nuanced roles that RNA methylation plays in key pathophysiological mechanisms, such as oxidative stress and angiogenesis, which are integral to the onset and progression of these diseases. By synthesizing the latest research, this review offers valuable insights into how RNA methylation could be harnessed for therapeutic interventions in the field of ophthalmology.

Role of CD4+ T cell-derived cytokines in the pathogenesis of uveitis

Uveitis refers to a diverse group of inflammatory diseases that affecting the uveal tract, comprising the iris, ciliary body, and choroid, with potential repercussions ranging from visual impairment to blindness. The role of autoimmunity in uveitis etiology is complex and still under investigation. CD4+ T cells intricately regulate immune responses in uveitis through their diverse subtypes: Th1, Th2, Th17, Treg (T regulatory), and Tfh (follicular T helper) cells. Each T cell subtype secretes specific cytokines with either pathogenic or protective implications in uveitis. Th1 cells, characterized by IFN-γ secretion and T-bet expression, drive type 1 immune responses against intracellular pathogens. Conversely, Th2 cells, which produce interleukin (IL)-4, IL-5, and IL-13 and express the transcription factor GATA3, mediate type 2 immune responses to larger extracellular threats like helminths. Th17 cells, generating IL-17 and IL-22 and controlled by RORγt, engage in type 3 immune responses against select pathogens. Tfh cells, releasing IL-21 and governed by Bcl6, aid B cell antibody production. Conversely, Tregs, identified by Foxp3, exert regulatory functions in immune homeostasis. This review delves into the roles of CD4+ T cell-derived cytokines in uveitis, emphasizing their intricate involvement in disease progression and resolution. Insight into these mechanisms might guide therapeutic approaches targeting CD4+ T cell responses in uveitis management.

Cytokines in Immune-mediated "Non-infectious" Uveitis

Uveitis is a significant cause of ocular morbidity and accounts for approximately 5 - 10% of visual impairments worldwide, particularly among the working-age population. Infections are the cause of ~ 50% cases of uveitis, but it has been suggested that infection might also be implicated in the pathogenesis of immune-mediated "non-infectious" uveitis. There is growing evidence that cytokines (i.e., interleukins, interferons, etc.) are key mediators of immune-mediated "non-infectious" uveitis. For example, activation of the interleukin-23/interleukin-17 signalling pathway is involved in immune-mediated "non-infectious" uveitis. Studies in animal models have been important in investigating the role of cytokines in uveitis. Recent studies of clinical samples from patients with uveitis have allowed the measurement of a considerable array of cytokines even from very small sample volumes (e.g., aqueous and vitreous humour). The identification of complex patterns of cytokines may contribute to a better understanding of their potential pathogenetic role in uveitis as well as to an improved diagnostic and therapeutic approach to treat these potentially blinding pathologies. This review provides further insights into the putative pathobiological role of cytokines in immune-mediated "non-infectious" uveitis.

Ocular immune-related diseases: molecular mechanisms and therapy

Ocular immune-related diseases, represent a spectrum of conditions driven by immune system dysregulation, include but not limit to uveitis, diabetic retinopathy, age-related macular degeneration, Graves' ophthalmopathy, etc. The molecular and cellular mechanisms underlying these diseases are typically dysfunctioned immune responses targeting ocular tissues, resulting in inflammation and tissue damage. Recent advances have further elucidated the pivotal role of different immune responses in the development, progression, as well as management of various ocular immune diseases. However, there is currently a relative lack of connection between the cellular mechanisms and treatments of several immune-related ocular diseases. In this review, we discuss recent findings related to the immunopathogenesis of above-mentioned diseases. In particular, we summarize the different types of immune cells, inflammatory mediators, and associated signaling pathways that are involved in the pathophysiology of above-mentioned ophthalmopathies. Furthermore, we also discuss the future directions of utilizing anti-inflammatory regime in the management of these diseases. This will facilitate a better understanding of the pathogenesis of immune-related ocular diseases and provide new insights for future treatment approaches.

The aryl hydrocarbon receptor: A crucial mediator in ocular disease pathogenesis and therapeutic target

The aryl hydrocarbon receptor (AHR) is a pivotal nuclear receptor involved in mediating cellular responses to a wide range of environmental pollutants and endogenous ligands. AHR plays a central role in regulating essential physiological processes, including xenobiotic metabolism, immune response modulation, cell cycle control, tumorigenesis, and developmental events. Recent studies have identified AHR as a critical mediator and a potential therapeutic target in the pathogenesis of ocular diseases. This review provides a thorough analysis of the various functions of AHR signalling in the ocular environment, with a specific emphasis on its effects on the retina, retinal pigment epithelium (RPE), choroid, and cornea. We provide a detailed discussion on the molecular mechanisms through which AHR integrates environmental and endogenous signals, influencing the development and progression of age-related macular degeneration (AMD), retinitis pigmentosa, uveitis, and other major ocular disorders. Furthermore, we evaluate the therapeutic potential of modulating AHR activity through novel ligands and agonists as a strategy for treating eye diseases. Understanding the molecular mechanisms of AHR in ocular tissues may facilitate the development of AHR-targeted therapies, which is crucial for addressing the pressing clinical demand for novel treatment strategies in ocular diseases.

Unravelling T-cell dynamics and immune responses in initial and recurrent uveitis

This study aimed to identify novel serological targets and investigate immune responses in patients with non-infectious uveitis, focusing on differences between initial onset and recurrent episodes. Differential gene expression analysis, immunocyte typing and T-cell receptor (TCR) gene analysis were conducted on RNA-sequenced peripheral blood samples from healthy individuals (n = 6) and non-infectious uveitis patients (n = 12), divided into 6 patients each at initial onset and recurrent stages. Peripheral blood T-cell types were analysed using flow cytometry. Bioinformatics methods included tools for RNA sequencing data processing, CIBERSORT for immune cell type prediction and specialized software for TCR repertoire analysis. Findings indicated that individuals with recurrent uveitis demonstrated a stronger adaptive immune response and a more pronounced immune imbalance compared to those with initial onset. Memory T cells were predominant in recurrent episodes, suggesting their potential role as biomarkers for disease progression. Significant differences in TCR diversity and V(D)J gene usage were observed between the various uveitis groups and healthy controls. Importantly, 38 uveitis-specific TCR sequences showed substantial expansion in the uveitis patients compared to controls. An elevated expansion of these specific TCR sequences was associated with an increased risk of uveitis development. The study highlights the critical role of adaptive immune responses and specific immune cell types in the pathogenesis of recurrent uveitis. Identification of the uveitis-specific TCR repertoire set could provide deeper insights into the disease and facilitate the development of targeted therapies for uveitis patients.

The management of adult and paediatric uveitis for rheumatologists

Uveitis encompasses multiple different conditions that are all characterized by intra-ocular inflammation. Uveitis occurs in the context of many different rheumatological conditions and carries a substantial risk to vision. Uveitis can develop both at the early stages of rheumatic diseases, sometimes even preceding other clinical features, and at later stages of disease. Uveitis can also occur as either a direct or an indirect complication of therapies used to treat patients with rheumatic disease. Conversely, patients with uveitis of non-rheumatic aetiology sometimes require immunosuppression, a treatment option that is not readily accessible to ophthalmologists. Thus, collaborative working between rheumatologists and ophthalmologists is critical for optimal management of patients with uveitis. This Review is written with rheumatologists in mind, to assist in the care of patients with uveitis. We collate and summarize the latest evidence and best practice in the diagnosis, management and prognostication of uveitis, including future trends and research priorities.

Targeting Oxidative Stress and Inflammation in the Eye: Insights from a New Model of Experimental Autoimmune Uveitis

Autoimmune uveitis is a relapsing blind-causing ocular condition with complex pathogenesis that is not completely understood. There is a high demand for accurate animal models of experimental autoimmune uveitis (EAU) suitable for elucidating the molecular mechanisms of the disease and testing new therapeutic approaches. Here, we demonstrated that photoreceptor Ca2+/Zn2+-sensor protein recoverin is a uveoretinal antigen in albino rabbits provoking typical autoimmune chorioretinitis 2-4 weeks after immunization. The pathologic process in recoverin-induced EAU shared features with human disease and included lymphocytic infiltration of the retina, Dalen-Fuchs nodules and foci of subtotal or total retinal atrophy, manifested as a decrease in amplitude of the a-wave of the electroretinogram. In some cases, changes in the retinal vascular pattern and subretinal hemorrhages were also observed. These signs were accompanied by a gradual accumulation of serum antibodies against recoverin. Biochemical examination of the aqueous humor (AH) revealed typical characteristics of inflammation and oxidative stress, including increased levels of TNF-α and IL-6 and decreased levels of IL-10, as well as decreased total antioxidant activity, superoxide dismutase and glutathione peroxidase activities, and increased zinc concentration. Consistently, metabolomic and targeted lipidomic analysis of AH showed high lactate and low ascorbic acid levels in early EAU; increased levels of key pro-inflammatory signaling lipids such as PGE2, TXB2, 11-HETE and Lyso-PAF; and reduced levels of the anti-inflammatory fatty acid DHA in advanced stages of the disease. Uveitic AH became enriched with recoverin, confirming disruption of the blood-ocular barrier and photoreceptor damage. Notably, the application of mitochondria-targeted antioxidant therapy impeded EAU progression by maintaining local antioxidant activity and suppressing TNF-α, IL-6 and PGE2 signaling. Overall, our results demonstrate that recoverin-induced EAU in rabbits represents an accurate model of human autoimmune posterior uveitis and suggest new directions for its therapy that can be trialed using the developed model.

"Infectious uveitis: a comprehensive systematic review of emerging trends and molecular pathogenesis using network analysis"

BACKGROUND

Infectious uveitis is a significant cause of visual impairment worldwide, caused by diverse pathogens such as viruses, bacteria, fungi, and parasites. Understanding its prevalence, etiology, pathogenesis, molecular mechanism, and clinical manifestations is essential for effective diagnosis and management.

METHODS

A systematic literature search was conducted using PubMed, Google Scholar, Web of Science, Scopus, and Embase, focusing on studies published in the last fifteen years from 2009 to 2023. Keywords included "uveitis," "infectious uveitis," "viral uveitis," and others. Rigorous inclusion and exclusion criteria were applied, and data were synthesized thematically. Gene symbols related to infectious uveitis were analyzed using protein-protein interaction (PPI) networks and pathway analyses to uncover molecular mechanisms associated with infectious uveitis.

RESULTS

The search from different databases yielded 97 eligible studies. The review identified a significant rise in publications on infectious uveitis, particularly viral uveitis, over the past fifteen years. Infectious uveitis prevalence varies geographically, with high rates in developing regions due to systemic infections and limited diagnostic resources. Etiologies include viruses (39%), bacteria (17%), and other pathogens, substantially impacting adults aged 20-50 years. Pathogenesis involves complex interactions between infectious agents and the ocular immune response, with key roles for cytokines and chemokines. The PPI network highlighted IFNG, IL6, TNF, and CD4 as central nodes. Enriched pathways included cytokine-cytokine receptor interaction and JAK-STAT signaling. Clinical manifestations range from anterior to posterior uveitis, with systemic symptoms often accompanying ocular signs. Diagnostic strategies encompass clinical evaluation, laboratory tests, and imaging, while management involves targeted antimicrobial therapy and anti-inflammatory agents.

CONCLUSION

This review underscores the complexity of infectious uveitis, driven by diverse pathogens and influenced by various geographical and systemic factors. Molecular insights from PPI networks and pathway analyses provide a deeper understanding of its pathogenesis. Effective management requires comprehensive diagnostic approaches and targeted therapeutic strategies.

Microglial-mediated immune mechanisms in autoimmune uveitis: Elucidating pathogenic pathways and targeted therapeutics

This review offers a comprehensive examination of the role of microglia in the pathogenesis of autoimmune uveitis, an inflammatory eye disease with significant potential for vision impairment. Central to our discussion is the dual nature of microglial cells, which act as both protectors and potential perpetrators in the immune surveillance of the retina. We explore the mechanisms of microglial activation, highlighting the key signaling pathways involved, such as NF-κB, JAK/STAT, MAPK, and PI3K/Akt. The review also delves into the genetic and environmental factors influencing microglial behavior, underscoring their complex interaction in disease manifestation. Advanced imaging techniques and emerging biomarkers for microglial activation, pivotal in diagnosing and monitoring the disease, are critically assessed. Additionally, we discuss current and novel therapeutic strategies targeting microglial activity, emphasizing the shift towards more precise and personalized interventions. This article aims to provide a nuanced understanding of microglial dynamics in autoimmune uveitis, offering insights into potential avenues for effective treatment and management.

Overview of dendritic cells and related pathways in autoimmune uveitis

Dendritic cells (DCs) play a crucial role in bridging innate and adaptive immune responses. They are widely distributed in various tissues and organs, including the eyes. In the ocular context, permanent DCs are present at the peripheral edge of the retina and the peripapillary area in an immature state. However, during the inflammatory process, DCs become activated and contribute to the development of uveitis. This review focuses on introducing the characteristics and status of DC-induced uveitis, exploring factors that can influence the status of DCs, and discussing feasible methods for treating DCs in both experimental autoimmune uveitis animal models and humans. It emphasizes the importance of further research on molecular pathways and signaling pathways that regulate the function of DCs. For example, investigating molecules such as cytotoxic T-lymphocyte-associated protein 4, which inhibits the B7-CD28 co-stimulatory interaction, can help improve immune homeostasis. The aim is to identify new therapeutic targets and develop targeted strategies for DCs, such as DC vaccine therapy or the use of immune modulators. These approaches can be tailored to the immune characteristics and disease manifestations of individual patients, enabling personalized treatment strategies. This may include the personalized design and precise medication of DC therapy, with the ultimate goal of improving treatment efficacy while minimizing adverse reactions.

Preclinical characterization of endotoxin-induced uveitis models using OCT, PET/CT and proteomics

Uveitis is a group of inflammatory ocular pathologies. Endotoxin-Induced Uveitis (EIU) model represent a well-known model induced by administration of Lipopolysaccharide (LPS). The aim is to characterize two models of EIU through two routes of administration with novel noninvasive imaging techniques. 29 rats underwent Intraocular Pressure (IOP) measurements, Optical Coherence Tomography (OCT), proteomic analysis, and Positron Emission Tomography and Computed Tomography (PET/CT). Groups included healthy controls (C), BSS administered controls (Ci), systemically induced EIU with LPS (LPSs), and intravitreally induced EIU with LPS (LPSi) for IOP, OCT, and proteomic studies. For 18F-FDG PET/CT study, animals were divided into FDG-C, FDG-LPSs and FDG-LPSi groups and scanned using a preclinical PET/CT system. LPSi animals exhibited higher IOP post-induction compared to C and LPSs groups. LPSi showed increased cellular infiltrate, fibrotic membranes, and iris inflammation. Proinflammatory proteins were more expressed in EIU models, especially LPSi. PET/CT indicated higher eye uptake in induced models compared to FDG-C. FDG-LPSi showed higher eye uptake than FDG-LPSs but systemic uptake was higher in FDG-LPSs due to generalized inflammation. OCT is valuable for anterior segment assessment in experimental models. 18F-FDG PET/CT shows promise as a noninvasive biomarker for ocular inflammatory diseases. Intravitreal induction leads to higher ocular inflammation. These findings offer insights for future inflammatory disease research and drug studies.

Topical ophthalmic instillation of engineered hMSCs-derived exosomes: A novel non-invasive therapeutic strategy for ocular posterior-segment disorder

Due to the presence of protective mechanisms and blood-ocular barriers in the eye, drugs aimed at treating posterior segment ophthalmic disorder have to be administrated mostly through periocular or intravitreal injection. In the current study, we sought to investigate whether topical ophthalmic instillation of human mesenchymal stem cells (hMSCs)-derived exosomes can prevent and treat experimental autoimmune uveitis (EAU), a posterior segment ophthalmic disease induced in animals and considered a model of human autoimmune diseases of the eye. Our studies reveal that topical ophthalmic instillation of hMSCs-derived exosomes can effectively ameliorate EAU. More importantly, we demonstrate that exosomes modified by trans-activator of transcription peptide (TAT) were more effective than naive exosomes in penetrating ocular barrier and preventing/treating EAU. Taken together, these results indicate that topical ophthalmic instillation of TAT-peptide modified exosomes represents a novel non-invasive therapeutic strategy for posterior-segment ophthalmic disorders.

Filgotinib in Active Noninfectious Uveitis: The HUMBOLDT Randomized Clinical Trial

Importance

Noninfectious uveitis is a leading cause of visual impairment with an unmet need for additional treatment options.

Objective

To assess the efficacy and safety of filgotinib, a Janus kinase 1 (JAK1) preferential inhibitor, for the treatment of noninfectious uveitis.

Design, Setting, and Participants

The HUMBOLDT trial was a double-masked, placebo-controlled, phase 2, randomized clinical trial conducted from July 2017 to April 2021 at 26 centers in 7 countries. Eligible participants (aged ≥18 years) had active noninfectious intermediate uveitis, posterior uveitis, or panuveitis despite at least 2 weeks of treatment with oral prednisone (10-60 mg per day).

Interventions

Participants were randomly assigned 1:1 to receive filgotinib, 200 mg, or placebo orally once daily for up to 52 weeks.

Main Outcomes and Measures

The primary end point was the proportion of participants experiencing treatment failure by week 24. Treatment failure was a composite end point represented by assessment of the presence of chorioretinal and/or retinal vascular lesions, best-corrected visual acuity, and anterior chamber cell and vitreous haze grades. Safety was assessed in participants who received at least 1 dose of study drug or placebo.

Results

Between July 26, 2017, and April 22, 2021, 116 participants were screened, and 74 (mean [SD] age, 46 [16] years; 43 female [59.7%] of 72 participants, as 2 participants did not receive treatment doses) were randomly assigned to receive filgotinib (n = 38) or placebo (n = 36). Despite early termination of the trial for business reasons ahead of meeting enrollment targets, a significantly reduced proportion of participants who received filgotinib experienced treatment failure by week 24 vs placebo (12 of 32 participants [37.5%] vs 23 of 34 participants [67.6%]; difference vs placebo -30.1%; 95% CI, -56.2% to -4.1%; P = .006). Business reasons were unrelated to efficacy or safety. Adverse events were reported in 30 of 37 participants (81.1%) who received filgotinib and in 24 of 35 participants (68.6%) who received placebo. Serious adverse events were reported in 5 of 37 participants (13.5%) in the filgotinib group and in 2 of 35 participants (5.7%) in the placebo group. No deaths were reported during the trial.

Conclusions and Relevance

Results of this randomized clinical trial show that filgotinib lowered the risk of treatment failure in participants with active noninfectious intermediate uveitis, posterior uveitis, or panuveitis vs placebo. Although the HUMBOLDT trial provided evidence supporting the efficacy of filgotinib in patients with active noninfectious uveitis, the premature termination of the trial prevented collection of additional safety or efficacy information of this JAK1 preferential inhibitor.

Trial Registration

ClinicalTrials.gov Identifier: NCT03207815.

Advances in Extracellular-Vesicles-Based Diagnostic and Therapeutic Approaches for Ocular Diseases

Extracellular vesicles (EVs) are nanoscale membrane vesicles of various sizes that can be secreted by most cells. EVs contain a diverse array of cargo, including RNAs, lipids, proteins, and other molecules with functions of intercellular communication, immune modulation, and regulation of physiological and pathological processes. The biofluids in the eye, including tears, aqueous humor, and vitreous humor, are important sources for EV-based diagnosis of ocular disease. Because the molecular cargos may reflect the biology of their parental cells, EVs in these biofluids, as well as in the blood, have been recognized as promising candidates as biomarkers for early diagnosis of ocular disease. Moreover, EVs have also been used as therapeutics and targeted drug delivery nanocarriers in many ocular disorders because of their low immunogenicity and superior biocompatibility in nature. In this review, we provide an overview of the recent advances in the field of EV-based studies on the diagnosis and therapeutics of ocular disease. We summarized the origins of EVs applied in ocular disease, assessed different methods for EV isolation from ocular biofluid samples, highlighted bioengineering strategies of EVs as drug delivery systems, introduced the latest applications in the diagnosis and treatment of ocular disease, and presented their potential in the current clinical trials. Finally, we briefly discussed the challenges of EV-based studies in ocular disease and some issues of concern for better focusing on clinical translational studies of EVs in the future.

Causal role of immune cells in uveitis: Mendelian randomization study

Background

Uveitis, characterized by inflammation of the iris, ciliary body, and choroid, presents a significant global clinical challenge, contributing substantially to visual impairment. Risk factors include autoimmune diseases and immune cell dysfunctions, yet many remain unidentified. Immune cells, notably T cells, B cells, and monocytes, play pivotal roles in uveitis pathogenesis. While biologic agents show promise, comprehensive studies on immune cell types in ocular diseases are lacking. Genome-wide association studies (GWAS) and Mendelian randomization (MR) present promising avenues to elucidate genetic susceptibilities and causal relationships between immune cell traits and uveitis risk.

Methods

Two-sample MR analysis was used to evaluate the causal relationship between 731 immune cells and uveitis, and genome-wide significance analysis was performed for genetic variation in 731 immune cells traits (P < 5 × 10-8). Immune characteristics include median fluorescence intensity (MFI), relative cell counts (RC), absolute cell counts (AC), and morphological parameters (MP), which were determined by published GWAS, and public data from the IEU Open GWAS database. The main analysis method of MR is inverse variance weighting (IVW). Heterogeneity and horizontal pleiotropy were also assessed.

Results

5 immunophenotypes, including CD62L-DC %DC, IgD+ CD38dim %B cell, CD3 on CM CD4+T cell, CD3 on CD45RA-CD4 +T cell, and CD3 on CD39+ CD4+ Treg may increase the risk of uveitis. 5 immunophenotypes, including CD11b on CD33dim HLA DR-Myeloid cell, HLA DR on CD33dim HLA DR+ CD11b-myeloid cell, CD14-CD16 + %monocyte, HLA DR on CD14-CD16 + monocyte and PDL-1 on CD14-CD16 + monocyte was negatively associated with the risk of uveitis. Among them, HLA DR on CD14-CD16 + monocyte (OR=0.921, 95%CI =0.875-0.970, P=0.001) and HLA DR on CD33dim HLA DR+ CD11b- (OR=0.879, 95%CI = 0.833-0.927, P=0.00) were negatively associated with the risk of uveitis in bi-direction.

Conclusion

These results indicate that 10 immune cells traits are significantly associated with the risk of developing uveitis and 2 of them were strongly associated with uveitis bi-directionally, after excluding the effects of confounding factors such as some immune diseases, which provided new ideas and therapeutic targets for the study of immune mechanism of uveitis.

Characterizing autoimmune uveitis to systemic diseases: a retrospective study from a Syrian tertiary reference center

Background

Uveitis, a notable cause of severe visual impairment, is frequently characterized as infectious or noninfectious autoimmune uveitis (AU), the latter of which is commonly associated with younger individuals and systemic diseases. Despite the condition's widespread impact, there are substantial gaps in the comprehension of its pathogenesis, clinical presentation, and therapeutic response, particularly concerning systemic disease-associated uveitis.

Aim of the study

The current study aims to bridge these gaps through an extensive examination of demographic and clinical features in AU patients, thereby informing future research, and therapeutic strategies, and improving patient outcomes.

Methods

This retrospective observational study analyzed 261 patients with systemic disease-associated uveitis from January 2018 to December 2022 in Damascus, Syria. With diagnoses made using the Standardization of Uveitis Nomenclature Working Group Criteria, the study evaluated tailored treatment efficacy at the 24-month post-treatment mark, alongside comprehensive ophthalmic examinations, laboratory evaluations, and radiographic assessments.

Results

In our study, included 87 patients with Systemic Disease-Associated Autoimmune Uveitis (SDA-AU). Women represented 64.36% of this group, and the mean age at diagnosis was 39.8±17.9 years (range 7-71) for men and 43.8±15.4 years (range 11-69). The most reported symptom was a painful red eye (52.87%). The onset of symptoms was sudden for 32.18% of patients, while 67.81% reported gradual development. Complications occurred in 33.33% of patients, including cataracts (41.37% of those with complications) and glaucoma (17.24%). Laboratory evaluations showed elevated inflammation markers in 66.66% of patients. Upon the 24-month assessment, 48.27% of patients achieved complete remission, 37.93% showed significant improvement, while disease worsened in 13.79% of cases.

Conclusion

Our findings demonstrated that the presentation of AU in this cohort frequently precedes the diagnosis of systemic diseases, affirming the vital role of an early and accurate diagnosis of uveitis for the detection of underlying systemic conditions. In conclusion, our study underlines the significance of a comprehensive and multidisciplinary approach in the management of SD-AU, leading to improved prognosis and quality of life for patients.

Interferons in vitreoretinal diseases; a review on their clinical application, and mechanism of action

PURPOSE

This review investigates the therapeutic benefits of interferons (IFNs) in vitreoretinal diseases, focusing on their regulatory roles in innate immunological reactions and angiogenesis. The study aims to categorize the clinical outcomes of IFN applications and proposes a molecular mechanism underlying their action.

METHODS

A systematic review was conducted using MEDLINE/PubMed, Web of Science, EMBASE, and Google Scholar databases to identify randomized clinical trials, case series, and case-control studies related to IFNs' impact on vitreoretinal diseases (1990-2022). The data synthesis involved an in-depth analysis of the anti-inflammatory and anti-angiogenesis effects of IFNs across various studies.

RESULTS

Our findings indicate that IFNs exhibit efficacy in treating inflammation-associated vitreoretinal disorders. However, a lack of sufficient evidence exists regarding the suitability of IFNs in angiogenesis-associated vitreoretinal diseases like choroidal neovascularization and diabetic retinopathies. The synthesis of data suggests that IFNs may not be optimal for managing advanced stages of angiogenesis-associated disorders.

CONCLUSION

While IFNs emerge as promising therapeutic candidates for inflammation-related vitreoretinal diseases, caution is warranted in their application for angiogenesis-associated disorders, especially in advanced stages. Further research is needed to elucidate the nuanced molecular pathways of IFN action, guiding their targeted use in specific vitreoretinal conditions.

AAV-mediated gene therapies for glaucoma and uveitis: are we there yet?

Glaucoma and uveitis are non-vascular ocular diseases which are among the leading causes of blindness and visual loss. These conditions have distinct characteristics and mechanisms but share a multifactorial and complex nature, making their management challenging and burdensome for patients and clinicians. Furthermore, the lack of symptoms in the early stages of glaucoma and the diverse aetiology of uveitis hinder timely and accurate diagnoses, which are a cause of poor visual outcomes under both conditions. Although current treatment is effective in most cases, it is often associated with low patient adherence and adverse events, which directly impact the overall therapeutic success. Therefore, long-lasting alternatives with improved safety and efficacy are needed. Gene therapy, particularly utilising adeno-associated virus (AAV) vectors, has emerged as a promising approach to address unmet needs in these diseases. Engineered capsids with enhanced tropism and lower immunogenicity have been proposed, along with constructs designed for targeted and controlled expression. Additionally, several pathways implicated in the pathogenesis of these conditions have been targeted with single or multigene expression cassettes, gene editing and silencing approaches. This review discusses strategies employed in AAV-based gene therapies for glaucoma and non-infectious uveitis and provides an overview of current progress and future directions.

Alkali injury-induced pathological lymphangiogenesis in the iris facilitates the infiltration of T cells and ocular inflammation

Inflammatory lymphangiogenesis is intimately linked to immune regulation and tissue homeostasis. However, current evidence has suggested that classic lymphatic vessels are physiologically absent in intraocular structures. Here, we show that neolymphatic vessels were induced in the iris after corneal alkali injury (CAI) in a VEGFR3-dependent manner. Cre-loxP-based lineage tracing revealed that these lymphatic endothelial cells (LECs) originate from existing Prox1+ lymphatic vessels. Notably, the ablation of iridial lymphangiogenesis via conditional deletion of VEGFR3 alleviated the ocular inflammatory response and pathological T cell infiltration. Our findings demonstrate that iridial neolymphatics actively participate in pathological immune responses following injury and suggest intraocular lymphangiogenesis as a valuable therapeutic target for the treatment of ocular inflammation.

The Therapeutic Trip of Melatonin Eye Drops: From the Ocular Surface to the Retina

Melatonin is a ubiquitous molecule found in living organisms, ranging from bacteria to plants and mammals. It possesses various properties, partly due to its robust antioxidant nature and partly owed to its specific interaction with melatonin receptors present in almost all tissues. Melatonin regulates different physiological functions and contributes to the homeostasis of the entire organism. In the human eye, a small amount of melatonin is also present, produced by cells in the anterior segment and the posterior pole, including the retina. In the eye, melatonin may provide antioxidant protection along with regulating physiological functions of ocular tissues, including intraocular pressure (IOP). Therefore, it is conceivable that the exogenous topical administration of sufficiently high amounts of melatonin to the eye could be beneficial in several instances: for the treatment of eye pathologies like glaucoma, due to the IOP-lowering and neuroprotection effects of melatonin; for the prevention of other dysfunctions, such as dry eye and refractive defects (cataract and myopia) mainly due to its antioxidant properties; for diabetic retinopathy due to its metabolic influence and neuroprotective effects; for macular degeneration due to the antioxidant and neuroprotective properties; and for uveitis, mostly owing to anti-inflammatory and immunomodulatory properties. This paper reviews the scientific evidence supporting the use of melatonin in different ocular districts. Moreover, it provides data suggesting that the topical administration of melatonin as eye drops is a real possibility, utilizing nanotechnological formulations that could improve its solubility and permeation through the eye. This way, its distribution and concentration in different ocular tissues may support its pleiotropic therapeutic effects.

Ocular toxicities in chimeric antigen receptor T-cell therapy: a real-world study leveraging FAERS database

Aim: The purpose of this study was to comprehensively explore the ocular toxicity associated with chimeric antigen receptor (CAR) T-cell therapy. Materials & methods: Data were assembled from the US FDA's Adverse Event Reporting System (FAERS) database from 2017 to 2023. Information component and reporting odds ratio methods were used for signal detection in total/categorized CAR T-cell therapy. Results: A total of 17 positive signals (preferred term) were detected, yet none of them were documented in the product information. Some adverse events were with death outcomes and overlapped a lot with cytokine-release syndrome. Conclusion: The ocular adverse events associated with CAR-T cell therapy are noteworthy, and it is imperative to maintain increased alertness and institute early intervention strategies.

Celastrol ameliorates experimental autoimmune uveitis through STAT3 targeting and gut microenvironment reprofiling

BACKGROUND

Extensive research has revealed the favorable effects of celastrol (CEL) against various diseases, but the role of CEL in autoimmune uveitis remains unexplored.

METHODS

We first assessed the prophylactical and therapeutical effects of CEL on autoimmune uveitis via rat experimental autoimmune uveitis model. After network pharmacology, functional enrichment and molecular docking analyses, we predicted the potential target of CEL and validated its effect on EAU by clinical and histopathological scores, Evans blue staining, immunofluorescence assay and western blotting. Then we evaluated the role of CEL in the gut environment by 16S rRNA sequencing and untargeted metabolomic analysis.

RESULTS

We confirmed that CEL treatment suppressed the pathological TH17 response, inhibited the migration of inflammatory cells, and preserved the integrity of BRB via targeting STAT3-IL17 pathway. Furthermore, CEL was found to reduce the relative abundance of opportunistic pathogenic bacteria including Clostridium_sensu_stricto_1, Parasutterella and GCA-900066575, and enrich the relative abundance of beneficial Oscillospirales and Ruminococcus_torques_group in EAU rats by fecal 16S rRNA sequencing. Meanwhile, CEL treatment reshaped the gut metabolites in the EAU rats by increasing the relative concentrations of cholic acid, progesterone and guggulsterone, and decreasing the relative levels of isoproterenol, creatinine and phenylacetylglutamine.

CONCLUSIONS

CEL exerts its ameliorative effects on the experimental autoimmune uveitis through the dual mechanisms of targeting STAT3 and reprofiling the gut microenvironment.

Morroniside ameliorates lipopolysaccharide-induced inflammatory damage in iris pigment epithelial cells through inhibition of TLR4/JAK2/STAT3 pathway

AIM

To investigate the effect of morroniside (Mor) on lipopolysaccharide (LPS)-treated iris pigment epithelial cells (IPE).

METHODS

IPE cells were induced by LPS and treated with Mor. Cell proliferation was detected by cell counting kit (CCK) -8, apoptosis was detected by flow cytometry, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA) kits, and the protein expression of TLR4, JAK2, p-JAK2, STAT3, and p-STAT3 was analyzed by Western blotting. In addition, overexpression of TLR4 and Mor treatment of LPS-stimulated IPE cells were also tested for the above indices.

RESULTS

Mor effectively promoted the proliferation and inhibited the apoptosis of LPS-treated IPE cells. In addition, Mor significantly reduced the levels of TNF-α, IL-6, and IL-8 and significantly inhibited the expression of TLR4, p-JAK2, and p-STAT3 in LPS-treated IPE cells. The effect of Mor on LPS-treated IPE cells was markedly attenuated after overexpression of TLR4.

CONCLUSION

These findings suggest that Mor may ameliorate LPS-induced inflammatory damage and apoptosis in IPE through inhibition of TLR4/JAK2/STAT3 pathway.

SOCS-JAK-STAT inhibitors and SOCS mimetics as treatment options for autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis

Autoimmune diseases arise from atypical immune responses that attack self-tissue epitopes, and their development is intricately connected to the disruption of the JAK-STAT signaling pathway, where SOCS proteins play crucial roles. Conditions such as autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis exhibit immune system dysfunctions associated with JAK-STAT signaling dysregulation. Emerging therapeutic strategies utilize JAK-STAT inhibitors and SOCS mimetics to modulate immune responses and alleviate autoimmune manifestations. Although more research and clinical studies are required to assess their effectiveness, safety profiles, and potential for personalized therapeutic approaches in autoimmune conditions, JAK-STAT inhibitors and SOCS mimetics show promise as potential treatment options. This review explores the action, effectiveness, safety profiles, and future prospects of JAK inhibitors and SOCS mimetics as therapeutic agents for psoriasis, autoimmune uveitis, systemic lupus erythematosus, and autoimmune encephalitis. The findings underscore the importance of investigating these targeted therapies to advance treatment options for individuals suffering from autoimmune diseases.

Sodium Ferrous Citrate and 5-Aminolevulinic Acid Exert a Therapeutic Effect on Endotoxin-Induced Uveitis in Rats

The metabolism of 5-aminolevulinic acid (ALA) is more efficient when combined with sodium ferrous citrate (SFC). Our previous study revealed that oral administration of ALA, which has anti-inflammatory properties, and SFC (ALA/SFC) immediately before lipopolysaccharide (LPS) inoculation suppressed endotoxin-induced uveitis (EIU) in rats. However, the therapeutic effect of ALA/SFC post-administration remains unexplored. Hence, this study aimed to evaluate the therapeutic efficacy of ALA/SFC on EIU in rats, which were administered with a gastric gavage of ALA/SFC (100/157 mg/kg) or prednisolone (Pred, 10 mg/kg) after 4 h of LPS inoculation. The treatment groups showed ameliorated clinical scores, inflammatory cells, protein levels in the aqueous humor (AqH), and histopathologic evaluation 24 h after LPS inoculation. Furthermore, the treatment groups had reduced tumor necrosis factor-α, nitric oxide, prostaglandin E2, and interleukin-6 levels in the AqH. ALA/SFC demonstrated an anti-inflammatory effect equivalent to that demonstrated by Pred. These findings indicate that ALA/SFC exerts a therapeutic effect on EIU in rats, indicating its clinical usefulness in uveitis treatment.

Next-generation nanomaterials: advancing ocular anti-inflammatory drug therapy

Ophthalmic inflammatory diseases, including conjunctivitis, keratitis, uveitis, scleritis, and related conditions, pose considerable challenges to effective management and treatment. This review article investigates the potential of advanced nanomaterials in revolutionizing ocular anti-inflammatory drug interventions. By conducting an exhaustive analysis of recent advancements and assessing the potential benefits and limitations, this review aims to identify promising avenues for future research and clinical applications. The review commences with a detailed exploration of various nanomaterial categories, such as liposomes, dendrimers, nanoparticles (NPs), and hydrogels, emphasizing their unique properties and capabilities for accurate drug delivery. Subsequently, we explore the etiology and pathophysiology of ophthalmic inflammatory disorders, highlighting the urgent necessity for innovative therapeutic strategies and examining recent preclinical and clinical investigations employing nanomaterial-based drug delivery systems. We discuss the advantages of these cutting-edge systems, such as biocompatibility, bioavailability, controlled release, and targeted delivery, alongside potential challenges, which encompass immunogenicity, toxicity, and regulatory hurdles. Furthermore, we emphasize the significance of interdisciplinary collaborations among material scientists, pharmacologists, and clinicians in expediting the translation of these breakthroughs from laboratory environments to clinical practice. In summary, this review accentuates the remarkable potential of advanced nanomaterials in redefining ocular anti-inflammatory drug therapy. We fervently support continued research and development in this rapidly evolving field to overcome existing barriers and improve patient outcomes for ophthalmic inflammatory disorders.

Pathogenesis and current therapies for non-infectious uveitis

Non-infectious uveitis (NIU) is a disorder with various etiologies and is characterized by eye inflammation, mainly affecting people of working age. An accurate diagnosis of NIU is crucial for appropriate therapy. The aim of therapy is to improve vision, relieve ocular inflammation, prevent relapse, and avoid treatment side effects. At present, corticosteroids are the mainstay of topical or systemic therapy. However, repeated injections are required for the treatment of chronic NIU. Recently, new drug delivery systems that may ensure intraocular delivery of therapeutic drug levels have been highlighted. Furthermore, with the development of immunosuppressants and biologics, specific therapies can be selected based on the needs of each patient. Immunosuppressants used in the treatment of NIU include calcineurin inhibitors and antimetabolites. However, systemic immunosuppressive therapy itself is associated with adverse effects due to the inhibition of immune function. In patients with refractory NIU or those who cannot tolerate corticosteroids and immunosuppressors, biologics have emerged as alternative treatments. Thus, to improve the prognosis of patients with NIU, NIU should be managed with different drugs according to the response to treatment and possible side effects.

γδ T cells in autoimmune uveitis pathogenesis: A promising therapeutic target

Autoimmune uveitis is a non-infectious, inflammatory intraocular disease that affects the uveal and adjacent tissues. It frequently causes varying degrees of visual loss. Evidence for the strong association between activated γδ T cells and the development of autoimmune uveitis is growing. The innate and adaptive immune response are connected in the early phases by the γδ T cells that contain the γ and δ chains. γδ T cells can identify antigens in a manner that is not constrained by the MHC. When activated by various pathways, γδ T cells can not only secrete pro-inflammatory factors early on (such as IL-17), but they can also promote Th17 cells responses, which ultimately exacerbates autoimmune uveitis. Therefore, we review the mechanisms by which γδ T cells affect autoimmune uveitis in different activation and disease states. Moreover, we also prospect for immunotherapies targeting different γδ T cell-related action pathways, providing a reference for exploring new drug for the treatment of autoimmune uveitis.

Interleukin-17 receptor C is essential for the pro-inflammatory pathogenicity of granulocyte-macrophage-colony-stimulating factor-producing T helper cells in experimental autoimmune uveitis

Autoimmune uveitis is an inflammatory disorder of the eye triggered by the responses of autoreactive T cells to ocular autoantigens. This study aims to understand the role of granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (ThGM) cells in the pathophysiology of mouse experimental autoimmune uveitis (EAU). We established an EAU model by immunizing mice with interphotoreceptor retinoid-binding protein (IRBP) 651-670. Splenic or eye-infiltrating ThGM cells were analyzed and enriched by flow cytometry according to the levels of an array of surface markers, transcription factors, and cytokines. Lentiviral transduction was conducted to silence or overexpress the target gene in differentiated ThGM cells. The adoptive transfer was applied to determine the pathogenicity of ThGM cells in vivo. We found that ThGM cells were present in the spleen and the eye after EAU induction. Both splenic and eye-infiltrating ThGM cells were phenotypically CD4⁺CCR7^-CXCR3^-CCR6^-CCR10^hi. Eye-infiltrating ThGM cells up-regulated interleukin-1β (IL-1β), interleukin-6 (IL-6), and IL-17 receptor C (IL-17RC) relative to splenic ThGM cells. IL-17RC overexpression enabled interleukin-17A (IL-17A)-induced up-regulation of IL-1β and IL-6 production in ThGM cells. Adoptive transfer of IL-17RC overexpressing ThGM cells exacerbated EAU severity, as evidenced by a higher histology score as well as increased pro-inflammatory cytokines and inflammatory cells in the eye. However, IL-17RC-silenced ThGM cells did not impact EAU. Therefore, for the first time, this study unveils the essential pro-inflammatory role of IL-17RC-expressing ThGM cells in EAU pathophysiology. We discovered a novel mechanism underlying the pathophysiology of autoimmune uveitis.

Association of TIM-3 with anterior uveitis and associated systemic immune diseases: a Mendelian randomization analysis

Background

We aimed to investigate the causal association between TIM-3, an immune checkpoint inhibitor, and anterior uveitis (AU), as well as associated systemic immune diseases.

Materials and methods

We performed two-sample Mendelian randomization (MR) analyses to estimate the causal effects of TIM-3 on AU and three associated systemic diseases, namely ankylosing spondylitis (AS), Crohn's disease (CD), and ulcerative colitis (UC). Single-nucleotide polymorphisms (SNPs) associated with AU, AS, CD, and UC were selected as the outcomes: AU GWAS with 2,752 patients with acute AU accompanied with AS (cases) and 3,836 AS patients (controls), AS GWAS with 968 cases and 336,191 controls, CD GWAS with 1,032 cases and 336,127 controls, and UC GWAS with 2,439 cases and 460,494 controls. The TIM-3 dataset was used as the exposure (n = 31,684). Four MR methods, namely, inverse-variance weighting (IVW), MR-Egger regression, weighted median, and weighted mode, were used in this study. Comprehensive sensitivity analyses were conducted to estimate the robustness of identified associations and the potential impact of horizontal pleiotropy.

Results

Our studies show that TIM-3 is significantly associated with CD using the IVW method (OR = 1.001, 95% CI = 1.0002-1.0018, P-value = 0.011). We also found that TIM-3 may be a protective factor for AU although these results lacked significance (OR = 0.889, 95% CI = 0.631-1.252, P-value = 0.5). No association was observed between the genetic predisposition to particular TIM-3 and susceptibility to AS or UC in this study. No potential heterogeneities or directional pleiotropies were observed in our analyses.

Conclusion

According to our study, a small correlation was observed between TIM-3 expression and CD susceptibility. Additional studies in different ethnic backgrounds will be necessary to further explore the potential roles and mechanisms of TIM-3 in CD.

IL-27-containing exosomes secreted by innate B-1a cells suppress and ameliorate uveitis

Introduction

IL-27 is a heterodimeric cytokine composed of Ebi3 and IL-27p28 and can exert proinflammatory or immune suppressive effects depending on the physiological context. Ebi3 does not contain membrane-anchoring motifs, suggesting that it is a secreted protein while IL-27p28 is poorly secreted. How IL-27p28 and Ebi3 dimerize in-vivo to form biologically active IL-27 is unknown. Major impediment to clinical use of IL-27 derives from difficulty of determining exact amount of bioavailable heterodimeric IL-27 needed for therapy.

Methods

To understand how IL-27 mediates immune suppression, we characterized an innate IL-27-producing B-1a regulatory B cell population (i27-Breg) and mechanisms i27-Bregs utilize to suppress neuroinflammation in mouse model of uveitis. We also investigated biosynthesis of IL-27 and i27-Breg immunobiology by FACS, immunohistochemical and confocal microscopy.

Results

Contrary to prevailing view that IL-27 is a soluble cytokine, we show that i27-Bregs express membrane-bound IL-27. Immunohistochemical and confocal analyses co-localized expression of IL-27p28 at the plasma membrane in association with CD81 tetraspanin, a BCR-coreceptor protein and revealed that IL-27p28 is a transmembrane protein in B cells. Most surprising, we found that i27-Bregs secrete IL-27-containing exosomes (i27-exosomes) and adoptive transfer of i27-exosomes suppressed uveitis by antagonizing Th1/Th17 cells, up-regulating inhibitory-receptors associated with T-cell exhaustion while inducing Treg expansion.

Discussion

Use of i27-exosomes thus obviates the IL-27 dosing problem, making it possible to determine bioavailable heterodimeric IL-27 needed for therapy. Moreover, as exosomes readily cross the blood-retina-barrier and no adverse effects were observed in mice treated with i27-exosome, results of this study suggest that i27-exosomes might be a promising therapeutic approach for CNS autoimmune diseases.

Effects of Oral 5-Aminolevulinic Acid on Lipopolysaccharide-Induced Ocular Inflammation in Rats

This study aimed to investigate the anti-inflammatory effect of 5-aminolevulinic acid (5-ALA) on endotoxin-induced uveitis (EIU) in rats. EIU was induced in male Sprague Dawley rats by the subcutaneous injection of lipopolysaccharide (LPS). During LPS injection, 5-ALA diluted with saline was administered via gastric gavage. After 24 h, clinical scores were assessed after which aqueous humor (AqH) samples were obtained. The number of infiltrating cells, protein concentration, and levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), and prostaglandin E2 (PGE2) in AqH were measured. For histological examination, both eyes of some rats were enucleated. In vitro, a mouse macrophage cell line (RAW264.7 cells) was stimulated by LPS with or without 5-ALA. Western blot was used to analyze the expression of inducible NO synthase (iNOS) and cyclooxygenase-2. 5-ALA suppressed the EIU clinical scores, infiltrating cell number, and protein concentration while improving the histopathologic scores. In particular, 100 mg/kg 5-ALA reduced the concentrations of NO, PGE2, TNF-α, and IL-6 in AqH, similar to 1 mg/kg prednisolone. In addition, 5-ALA suppressed iNOS upregulation in LPS-stimulated RAW264.7 cells. Therefore, 5-ALA has an anti-inflammatory effect on EIU through the inhibition of the upregulation of inflammatory mediators.

Perspectives of Therapeutic Drug Monitoring of Biological Agents in Non-Infectious Uveitis Treatment: A Review

Biological drugs, especially those targeting anti-tumour necrosis factor α (TNFα) molecule, have revolutionized the treatment of patients with non-infectious uveitis (NIU), a sight-threatening condition characterized by ocular inflammation that can lead to severe vision threatening and blindness. Adalimumab (ADA) and infliximab (IFX), the most widely used anti-TNFα drugs, have led to greater clinical benefits, but a significant fraction of patients with NIU do not respond to these drugs. The therapeutic outcome is closely related to systemic drug levels, which are influenced by several factors such as immunogenicity, concomitant treatment with immunomodulators, and genetic factors. Therapeutic drug monitoring (TDM) of drug and anti-drug antibody (ADAbs) levels is emerging as a resource to optimise biologic therapy by personalising treatment to bring and maintain drug concentration within the therapeutic range, especially in those patients where a clinical response is less than expected. Furthermore, some studies have described different genetic polymorphisms that may act as predictors of response to treatment with anti-TNFα agents in immune-mediated diseases and could be useful in personalising biologic treatment selection. This review is a compilation of the published evidence in NIU and in other immune-mediated diseases that support the usefulness of TDM and pharmacogenetics as a tool to guide clinicians’ treatment decisions leading to better clinical outcomes. In addition, findings from preclinical and clinical studies, assessing the safety and efficacy of intravitreal administration of anti-TNFα agents in NIU are discussed.

Analysis of differentially expressed genes in individuals with noninfectious uveitis based on data in the gene expression omnibus database

Noninfectious uveitis (NIU), an intraocular inflammation caused by immune-mediated reactions to eye antigens, is associated with systemic rheumatism and several autoimmune diseases. However, the mechanisms underlying the pathogenesis of uveitis are poorly understood. Therefore, we aimed to identify differentially expressed genes (DEGs) in individuals with NIU and to explore its etiologies using bioinformatics tools. GSE66936 and GSE18781 datasets from the gene expression omnibus (GEO) database were merged and analyzed. Functional enrichment analysis was performed, and protein-protein interaction (PPI) networks were constructed. A total of 89 DEGs were identified. Gene ontology (GO) enrichment analysis identified 21 enriched gene sets. Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis identified four core enriched pathways: antigen processing and expression signaling, natural killer (NK) cell-mediated cytotoxicity signaling, glutathione metabolic signal transduction, and arachidonic acid metabolism pathways. PPI network analysis revealed an active component-target network with 40 nodes and 132 edges, as well as several hub genes, including CD27, LTF, NCR3, SLC4A1, CD69, KLRB1, KIR2DL3, KIR3DL1, and GZMK. The eight potential hub genes may be associated with the risk of developing NIU. NK cell-mediated cytotoxicity signaling might be the key molecular mechanism in the occurrence and development of NIU. Our study provided new insights on NIU, its genetics, molecular pathogenesis and new therapeutic targets.

Identification of uveitis-associated functions based on the feature selection analysis of gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment scores

Uveitis is a typical type of eye inflammation affecting the middle layer of eye (i.e., uvea layer) and can lead to blindness in middle-aged and young people. Therefore, a comprehensive study determining the disease susceptibility and the underlying mechanisms for uveitis initiation and progression is urgently needed for the development of effective treatments. In the present study, 108 uveitis-related genes are collected on the basis of literature mining, and 17,560 other human genes are collected from the Ensembl database, which are treated as non-uveitis genes. Uveitis- and non-uveitis-related genes are then encoded by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment scores based on the genes and their neighbors in STRING, resulting in 20,681 GO term features and 297 KEGG pathway features. Subsequently, we identify functions and biological processes that can distinguish uveitis-related genes from other human genes by using an integrated feature selection method, which incorporate feature filtering method (Boruta) and four feature importance assessment methods (i.e., LASSO, LightGBM, MCFS, and mRMR). Some essential GO terms and KEGG pathways related to uveitis, such as GO:0001841 (neural tube formation), has04612 (antigen processing and presentation in human beings), and GO:0043379 (memory T cell differentiation), are identified. The plausibility of the association of mined functional features with uveitis is verified on the basis of the literature. Overall, several advanced machine learning methods are used in the current study to uncover specific functions of uveitis and provide a theoretical foundation for the clinical treatment of uveitis.

Photoreceptor Cells Constitutively Express IL-35 and Promote Ocular Immune Privilege

Interleukin-27 is constitutively secreted by microglia in the retina or brain, and upregulation of IL-27 during neuroinflammation suppresses encephalomyelitis and autoimmune uveitis. However, while IL-35 is structurally and functionally similar to IL-27, the intrinsic roles of IL-35 in CNS tissues are unknown. Thus, we generated IL-35/YFP-knock-in reporter mice (p35-KI) and demonstrated that photoreceptor neurons constitutively secrete IL-35, which might protect the retina from persistent low-grade inflammation that can impair photoreceptor functions. Furthermore, the p35-KI mouse, which is hemizygous at the il12a locus, develops more severe uveitis because of reduced IL-35 expression. Interestingly, onset and exacerbation of uveitis in p35-KI mice caused by extravasation of proinflammatory Th1/Th17 lymphocytes into the retina were preceded by a dramatic decrease of IL-35, attributable to massive death of photoreceptor cells. Thus, while inflammation-induced death of photoreceptors and loss of protective effects of IL-35 exacerbated uveitis, our data also suggest that constitutive production of IL-35 in the retina might have housekeeping functions that promote sterilization immunity in the neuroretina and maintain ocular immune privilege.

The efficacy and safety of TNF inhibitor (golimumab) as salvage treatment in patients with refractory noninfectious uveitis

BACKGROUND

Tumor necrosis factor inhibitor (TNFi) is recently reported to treat noninfectious uveitis (NIU) effectively. However, as a new kind of TNFi, golimumab is just on the market in China for several years, and its administration for NIU treatment lacks sufficient evidence. Therefore, the current study aimed to investigate the efficacy and safety of golimumab in refractory NIU patients.

METHODS

Thirty NIU patients with 49 affected eyes refractory to conventional treatments (corticosteroids and immunosuppressive agents) were consecutively enrolled. They received treatment of TNFi (50 mg golimumab every 4 weeks) for at least 6 months. The anterior chamber cell grade, vitreous haziness grade, central macular thickness, and visual acuity were evaluated at baseline, month (M) 1, M3, and M6.

RESULTS

After treatment, the anterior chamber cell grade declined from baseline (0.6 ± 0.7) to M6 (0.3 ± 0.5) (P < 0.001); the vitreous haziness grade decreased from baseline (1.2 ± 1.2) to M6 (0.4 ± 0.5) (P < 0.001); meanwhile, the central macular thickness also reduced from baseline (351.4 ± 90.8 μm) to M6 (271.8 ± 54.4 μm) (P < 0.001). In terms of visual acuity (LogMAR), it showed a declined trend from baseline (0.5 ± 0.3) to M6 (0.4 ± 0.2), but without statistical significance (P = 0.096). Subgroup analyses revealed that TNFi history related to decreased golimumab efficacy. In addition, 13.3% of patients had adverse events, including elevated liver enzymes (6.7%), fatigue (3.3%), and rash (3.3%).

CONCLUSION

Golimumab is effective and safe for refractory NIU treatment, while a large-scale trial is still needed for verification.

A review of investigated risk factors for developing equine recurrent uveitis

Equine recurrent uveitis (ERU) is an ocular inflammatory disease that can be difficult to manage clinically. As such, it is the leading cause of bilateral blindness for horses. ERU is suspected to have a complex autoimmune etiology with both environmental and genetic risk factors contributing to onset and disease progression in some or all cases. Work in recent years has aimed at unraveling the primary triggers, such as infectious agents and inherited breed-specific risk factors, for disease onset, persistence, and progression. This review has aimed at encompassing those factors that have been associated, implicated, or substantiated as contributors to ERU, as well as identifying areas for which additional knowledge is needed to better understand risk for disease onset and progression. A greater understanding of the risk factors for ERU will enable earlier detection and better prognosis through prevention and new therapeutics.

Association between meteorological factors and hospital admissions for uveitis in Hefei, China: a time-series study

Meteorological variables are regarded as risk factors for inflammatory diseases, but their associations with uveitis, one of the leading causes accounting for blindness worldwide with an estimated prevalence of 38-714 cases/100,000 person-years, have not been thoroughly investigated. The present study explored the short-term association between meteorological variables and hospital admissions for uveitis in Hefei City, China. Daily data on uveitis hospital admissions and meteorological variables including mean temperature (MT) (°C), diurnal temperature range (DTR) (°C), and relative humidity (RH) (%), from 2014 to 2020, were collected. A time-series study using generalized linear model combined with distributed lag non-linear model was applied. Totally, 1911 admissions for uveitis including 894 first admissions and 1017 readmissions were reported during the study period. The associations of high percentile of MT (75th, 24.5℃) and low percentile of DTR (25th, 5.4℃) with uveitis admissions were observed to be statistically significant from lag9 (RR = 1.041, 95%CI: 1.002-1.081) to lag11 (RR = 1.053, 95%CI: 1.003-1.104) and lag4 (RR = 1.053, 95%CI: 1.019-1.088) to lag5 (RR = 1.052, 95%CI: 1.020-1.085), respectively. Moreover, a significant association between low percentile of RH (1th, 44%) and uveitis admissions appeared at lag0-8 (RR = 1.869, 95%CI: 1.017-3.434) and lasted until lag0-13 (RR = 2.539, 95%CI: 1.102-5.850) in the cumulative lag structure. Subgroup analyses indicated that males and the young seemed to be more sensitive to high MT exposure, while females appeared to be more vulnerable to low DTR exposure. Interestingly, both the young and the elderly are susceptible to low DTR and low RH exposure. Furthermore, high MT and low DTR exposure were associated with increased risk of first admission for uveitis. In summary, exposure to high-value of MT and low-value of DTR and RH may increase the hospital admissions for uveitis, especially for the status of first admission.