Calcineurin Inhibitor Voclosporin Preserves Corneal Barrier and Conjunctival Goblet Cells in Experimental Dry Eye

Role of NADPH Oxidase 4 on Dry Eye Syndrome in Mice

Objective: This study aims to investigate the effect of NADPH oxidase 4 (NOX4)-mediated inflammation on concanavalin A (ConA)-induced dry eye syndrome (DES) in mice. Methods: Thirty-six mice were randomly divided into Control, Model, no-load Control, and NOX4 interference group. Adenovirus was injected (10 μL) into the lacrimal glands of both eyes of mice in no-load Control group and NOX4 interference group. Four days after adenovirus injection, the Control group was injected with phosphate-buffered saline, and the other groups were injected with ConA (200 μg) in the lacrimal glands of mice to establish DES models. The tear secretion rate was estimated by phenol red thread test. Lissamine green eye staining was used to evaluate conjunctival damage. The corneal surface was observed by hematoxylin-eosin (HE) staining and scanning electron microscopy (SEM). The morphology and quantity of conjunctival epithelial cells and goblet cells were observed by Periodic acid-Schiff staining. The expression of NOX4, NOD-like receptor thermal protein domain-associated protein 3 (NLRP3), interleukin-1β (IL-1β), and mucin 5 subtype AC (MUC5AC) was detected by immunohistochemistry. Results: Compared with the Control group, the Model group showed a significant decrease in tear secretion and an upregulation in microscopic image score. The HE staining and SEM showed corneal and conjunctiva damage in the Model group. The protein expression of NOX4, NLRP3, and IL-1β was upregulated, but MUC5AC was downregulated in the Model group. After interfering with NOX4, all these indicators were reversed. Conclusion: The pathological process of concanavalin A-induced DES appears to be related to NOX4.

Voclosporin: Unique Chemistry, Pharmacology and Toxicity Profile, and Possible Options for Implementation into the Management of Lupus Nephritis

Calcineurin inhibitors (CNI) can suppress allo- and autoimmunity by suppressing T cell function but also have anti-proteinuric effects by stabilizing the cellular components of the kidney's filtration barrier. Therefore, CNI are used in autoimmune kidney diseases with proteinuria. However, the traditional CNI, cyclosporine A and tacrolimus, have a narrow therapeutic range, need monitoring of drug levels, and their use is associated with nephrotoxicity and metabolic alterations. Voclosporin (VOC), a novel CNI, no longer requires drug level monitoring and seems to lack these adverse effects, although hypertension and drug-drug interactions still occur. VOC demonstrated efficacy superior to standard-of-care in controlling active lupus nephritis in the phase 2 AURA-LV and the phase 3 AURORA-1 trials and was approved for the treatment of active lupus nephritis. However, how to implement VOC into the current and changing treatment landscape of lupus nephritis is still debated. Here, we review the unique chemistry, pharmacology, and toxicity profile of VOC, summarize the efficacy and safety data from the AURA-LV and AURORA-1 trials, and discuss the following four possible options to implement VOC into the management of lupus nephritis, namely regarding B cell-targeting therapy with belimumab (BEL). These include: 1. patient stratification to either VOC or BEL, 2. VOC/BEL combination therapy, 3. VOC-BEL sequential therapy, or 4. alternative options for the rapid antiproteinuric effect of VOC.

Molecular nature of ocular surface barrier function, diseases that affect it, and its relevance for ocular drug delivery

The structural and functional integrity of the ocular surface, a continuous epithelial structure comprised of the cornea, the conjunctiva, and the ductal surface of the lacrimal as well as meibomian glands, is crucial for proper vision. The ocular surface barrier function (OSBF), sum of the different types of protective mechanisms that exist at the ocular surface, is essential to protect the rest of the eye from vision-threatening physical, chemical, and biological insults. OSBF helps maintain the immune privileged nature of the cornea and the aqueous humor by preventing entry of infectious agents, allergens, and noxious chemicals. Disruption of OSBF exposes the dense nerve endings of the cornea to these stimuli, resulting in discomfort and pain. This review summarizes the status of our knowledge related to the molecular nature of OSBF, describes the effect of different ocular surface disorders on OSBF, and examines the relevance of this knowledge for ocular drug delivery.

The Effect of Anti-Inflammatory Topical Ophthalmic Treatments on In Vitro Corneal Epithelial Cells

Purpose

To compare the effect of three commonly prescribed anti-inflammatory eye drops on corneal epithelial cells in vitro.

Methods

Three different lines of human corneal epithelial cells were tested: primary cells cultured from donor tissue, commercially available primary cells, and immortalized cells. Cells were seeded on 96-well plates and treated with the following eye drops: cyclosporine 0.05%, lifitegrast 5%, and tacrolimus 0.03% or 0.1%. Exposure times tested were 30 seconds, 1 minute, 2 minutes, 1 hour, 2 hours, 4 hours, and 24 hours. Brightfield images and viability assays were analyzed 48 to 72 hours after the initiation of treatments. At least five replicates were tested per drug and time exposure.

Results

Commercially obtained primary cells showed reduced viability following 1 hour with tacrolimus 0.1% (8%; P = 0.043%) and 4 hours with tacrolimus 0.03% (17%; P = 0.042%). Lifitegrast exposure reduced primary cell viability after 4 hours (10%; P = 0.042). Cell viability in primary cells was not deleteriously affected following exposure to cyclosporine for up to 4 hours. A similar trend was observed in both primary cells cultured from donor tissue and immortalized human corneal epithelial cells, demonstrating greater decreases in cell viability in tacrolimus compared to lifitegrast and cyclosporine. Light microscopy imaging for analysis of cell morphology and confluence supported the results.

Conclusions

Tacrolimus showed the highest impact on corneal epithelium survival in vitro, and cyclosporine proved the most protective.

Translational Relevance

Comparing anti-inflammatory eye drops on corneal epithelial cells in vitro may inform eye drop selection and development for clinical purposes.

IL-17 Producing Lymphocytes Cause Dry Eye and Corneal Disease With Aging in RXRα Mutant Mouse

Purpose

To investigate IL-17 related mechanisms for developing dry eye disease in the Pinkie mouse strain with a loss of function RXRα mutation.

Methods

Measures of dry eye disease were assessed in the cornea and conjunctiva. Expression profiling was performed by single-cell RNA sequencing (scRNA-seq) to compare gene expression in conjunctival immune cells. Conjunctival immune cells were immunophenotyped by flow cytometry and confocal microscopy. The activity of RXRα ligand 9-cis retinoic acid (RA) was evaluated in cultured monocytes and γδ T cells.

Results

Compared to wild type (WT) C57BL/6, Pinkie has increased signs of dry eye disease, including decreased tear volume, corneal barrier disruption, corneal/conjunctival cornification and goblet cell loss, and corneal vascularization, opacification, and ulceration with aging. ScRNA-seq of conjunctival immune cells identified γδ T cells as the predominant IL-17 expressing population in both strains and there is a 4-fold increased percentage of γδ T cells in Pinkie. Compared to WT, IL-17a, and IL-17f significantly increased in Pinkie with conventional T cells and γδ T cells as the major producers. Flow cytometry revealed an increased number of IL-17⁺ γδ T cells in Pinkie. Tear concentration of the IL-17 inducer IL-23 is significantly higher in Pinkie. 9-cis RA treatment suppresses stimulated IL-17 production by γδ T and stimulatory activity of monocyte supernatant on γδ T cell IL-17 production. Compared to WT bone marrow chimeras, Pinkie chimeras have increased IL-17⁺ γδ T cells in the conjunctiva after desiccating stress and anti-IL-17 treatment suppresses dry eye induced corneal MMP-9 production/activity and conjunctival goblet cell loss.

Conclusion

These findings indicate that RXRα suppresses generation of dry eye disease-inducing IL-17 producing lymphocytes s in the conjunctiva and identifies RXRα as a potential therapeutic target in dry eye.

Current Advances in Mechanisms and Treatment of Dry Eye Disease: Toward Anti-inflammatory and Immunomodulatory Therapy and Traditional Chinese Medicine

Dry eye is currently one of the most common ocular surface disease. It can lead to ocular discomfort and even cause visual impairment, which greatly affects the work and quality of life of patients. With the increasing incidence of dry eye disease (DED) in recent years, the disease is receiving more and more attention, and has become one of the hot research fields in ophthalmology research. Recently, with the in-depth research on the etiology, pathogenesis and treatment of DED, it has been shown that defects in immune regulation is one of the main pathological mechanisms of DED. Since the non-specific and specific immune response of the ocular surface are jointly regulated, a variety of immune cells and inflammatory factors are involved in the development of DED. The conventional treatment of DED is the application of artificial tears for lubricating the ocular surface. However, for moderate-to-severe DED, treatment with anti-inflammatory drugs is necessary. In this review, the immunomodulatory mechanisms of DED and the latest research progress of its related treatments including Chinese medicine will be discussed.

Retinoid Regulation of Ocular Surface Innate Inflammation

Corneal and conjunctival inflammation and dry eye develop in systemic vitamin A deficiency (VAD). The objective of this study was to investigate the lacrimal ocular surface retinoid axis, particularly immunomodulatory effects of retinoic acid (RA) and change in conjunctival myeloid cell number and phenotype in VAD. We discovered that ocular surface epithelial and myeloid cells express retinoid receptors. Both all trans- and 9-cis-RA suppressed production of dry eye relevant inflammatory mediators [interleukin(IL)-1β, IL-12, regulated upon activation, normal T cell expressed and secreted (RANTES)] by myeloid cells. Systemic VAD was associated with significant goblet cell loss and an increased number of CD45+ immune cells in the conjunctiva. MHCII^-CD11b⁺ classical monocytes were significantly increased in the conjunctiva of VAD C57BL/6 and RXR-α mutated Pinkie strains. RNA seq revealed significantly increased expression of innate immune/inflammatory genes in the Pinkie conjunctiva. These findings indicate that retinoids are essential for maintaining a healthy, well-lubricated ocular surface and have immunomodulatory effects in the conjunctiva that are mediated in part via RXR-α signaling. Perturbation of the homeostatic retinoid axis could potentiate inflammation on the ocular surface.

Modulation of Oxidative Stress and Inflammation in the Aged Lacrimal Gland

Inflammation and oxidative stress accompany aging. This study investigated the interplay between oxidative stress and inflammation in the lacrimal gland. C57BL/6 mice were used at 2 to 3, 12, and 24 months of age. Nuclear factor erythroid derived-2-related factor 2 (Nrf2)^-/- and corresponding wild-type mice were used at 2 to 3 and 12 to 13 months of age. A separate group of 15.5 to 17 months of age C57BL/6 mice received a diet containing an Nrf2 inducer (Oltipraz) for 8 weeks. Aged C57BL/6 lacrimal glands showed significantly greater lymphocytic infiltration, higher levels of MHC II, IFN-γ, IL-1β, TNF-α, and cathepsin S (Ctss) mRNA transcripts, and greater nitrotyrosine and 4-hydroxynonenal protein. Young Nrf2^-/- mice showed an increase in IL-1β, IFN-γ, MHC II, and Ctss mRNA transcripts compared with young wild-type mice and greater age-related changes at 12 to 13 months of age. Oltipraz diet significantly decreased nitrotyrosine and 4-hydroxynonenal and decreased the expression of IL-1β and TNF-α mRNA transcripts, while decreasing the frequency of CD45⁺CD4⁺ cells in lacrimal glands and significantly increasing conjunctival goblet cell density compared with a standard diet. The findings provide novel insight into the development of chronic, low-grade inflammation and oxidative stress in age-related dry eye. New therapies targeting oxidative stress pathways will be valuable in treating age-related dry eye.