Reduced RXRα signaling increases dry eye disease inducing γδT17 cells in the conjunctiva

Abstract

Purpose : To investigate the mechanism 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 by single-cell RNA sequencing (scRNA-seq) was performed to compare gene expression in conjunctival immune cells. Conjunctival immune cells were immunophenotyped by flow cytometry and confocal microscopy. Activity of RXRα ligand 9-cis retinoic acid (RA) was evaluated in cultured monocytes and γδT cells.

Results : Compared to wild type (WT) C57BL/6, Pinkie has increased signs of dry eye disease, including corneal barrier disruption, conjunctival cornification and goblet cell loss, and corneal vascularization, opacification, and ulceration with aging. scRNA-seq of conjunctival immune cells identified γδT cells as the predominant IL-17 expressing population in both strains and there is a 4-fold increased percentage of γδT cells in Pinkie. Compared to WT, significantly increased expression of IL-17a and IL-17f in conventional T cells and IL-17f in γδT cells was found in Pinkie. Flow cytometry and immunostaining revealed an increased number of IL-17⁺ γδT 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 γδT and stimulatory activity of monocyte supernatant on γδT cell IL-17 production. Compared to WT bone marrow chimeras, Pinkie chimeras have increased IL-17⁺ γδT 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.

Conclusions : These findings indicate that RXRα suppresses generation of dry eye disease inducing γδT17 cells in the conjunctiva and identifies RXRα as a potential therapeutic target in dry eye.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.