Diet-induced gut dysbiosis alters corneal immune cell distribution and gene expression in response to wounding

Abstract

Purpose : Recent studies have shown that commensal microbiome secretes various metabolites that can exert important effects on the host immunity, control inflammation and alter cellular biological functions. The gut microbiome is strongly altered by diets. However, little is known regarding the effect of microbiome on corneal immunity and corneal genetic expression. The purpose of this study is to describe the effect of diet-induced gut dysbiosis on corneal immunity and corneal gene expression after wounding.

Methods : This study is approved by the Animal Care and Use of the University of Illinois at Chicago. Five-week-old female C57BL6 mice were fed on a normal chow diet (ND), isocaloric low fat control diet (LD) or a 21% milk fat diet (simulating a Western Style, WD) for six weeks. A 2mm corneal epithelial debridement was performed(n=10). Cecal samples from mice were used for microbial diversity analysis(n>3). Immunofluorescence staining of corneal wholemount tissue at time 0 and 18 hours of debridement was used to visualize immune cell distribution, including anti-CD45, anti-LY6G, anti-TCR delta gamma, etc. RNA Seq using Illumina NovaSeq 6000 was performed from corneas 18 hours post debridement. RNA STAR was used to align transcripts to mm10 mouse genome. DESeq2 was used to perform differential gene analysis.

Results : Mice fed different diets had significant alterations in gut microbial alpha and beta diversities. After corneal debridement, increased TCR was observed in LD group, and decreased LY6G was observed in HFD group (p<0.05). 3158 genes were differentially expressed with 225 genes with greater than two-fold change. Go terms of differentially expressed genes included responses to external stimulus, cell proliferation, migration, adhesion, defense response, immune system process, leukocyte migration, etc. Top over-represented KEGG pathways included ECM-receptor interaction, Cytokine-cytokine receptor interaction, Focal adhesion, Hematopoietic cell lineage, Leukocyte transendothelial migration, etc.

Conclusions : Gut microbial dysbiosis may alter corneal immune cell distribution and genes related to epithelial function and corneal immunity.

This is a 2021 ARVO Annual Meeting abstract.