Abstract
Purpose :
Dry eye causes corneal inflammation, epitheliopathy and sensorineural changes. This study evaluated the hypothesis that desiccating stress (DS) alters the percentages and transcriptional profiles of immune cell populations in the cornea.
Methods :
Desiccating stress (DS) induced dry eye was created by suppressing tear secretion and exposure to drafty low humidity environment. Expression profiling of sorted corneal immune cells was performed by single-cell RNA sequencing (scRNA-seq). Cell differentiation trajectories and cell fate were modeled through RNA velocity analysis. Confocal microscopy was used to immunodetect corneal immune cells and epithelial nerve plexus.
Results :
Based on transcriptional profiles twelve corneal immune cell populations were identified at baseline that consist of monocytes, resident (rMP) and MMP13 high macrophages, dendritic cells (cDC2), neutrophils, mast cells, pre T/B cells, and innate (gdT, ILC2, NK) and conventional T and B lymphocytes. T cells and resident macrophages (rMP) were the largest populations in the normal cornea comprising 18.6 and 18.25% respectively. rMP increased to 55.2% of cells after 5 days of DS. Significant changes in expression of 1365 genes (Padj < 0.0001) were noted in these cells with increases in cytokines and chemokines (Tnf, Cxcl1, Il1rn), inflammatory markers (Icam, Vcam, Adam17), the TAM receptor (Mertk), and decreases in complement and MHCII genes. A differentiation trajectory from monocytes to terminal state rMP was found. Phagocytosis, C-type lectin receptor signaling, NF-kappa B signaling and Toll-like receptor signaling were among the pathways with increased activity in these cells.
MRC1+ rMPs were observed in the basal epithelium adjacent to epithelial nerve plexus and topical CXCL1 application increased corneal sensitivity.
Conclusions :
Dry eye recruits monocytes that differentiate to macrophages with increased expression of phagocytic and inflammatory genes. The proximity of these cells to the epithelial nerve plexus and their expression of neurosensitizers suggests they may contribute to the sensorineural changes in dry eye.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.