Shared microbiota profile in the retina, choroid and the gut

Abstract

Purpose : This study aims to investigate the microbiota of the retina, choroid, and gut under normal physiological conditions, with a focus on the microbial connections between the gut and the eye (Gut-Eye Axis).

Methods : 6-8 week-old healthy C57BL/6J mice were used in this study. The retina, choroid, and feces from the same animals (n=8) were collected using nuclease-free vials. DNA was extracted using the QIAamp DNA Stool Mini Kit (Qiagen 51504), followed by library preparation and amplification. The purified PCR products were pooled in equimolar ratios and subjected to paired-end sequencing (2×250) on an Illumina platform following the manufactures instructions. The raw reads were submitted to the NCBI SRA database.

Results : Samples from the retina, choroid, and feces exhibited a healthy state of microbiotas. The three predominant phyla were Firmicutes (relative abundances: retina = 30.2%, choroid = 27.7%, fence = 43.5%), Proteobacteria (relative abundances: retina = 34.9%, choroid = 30.5%, fence = 26.4%), and Actinobacteria (relative abundances: retina = 20.4%, choroid = 19.4%, fence = 9.5%). The Observed and Shannon alpha diversity metrics indicate that the microbiota of fence exhibits greater richness and evenness compared to the choroid. There are significant differences in the microbiota composition in these samples. The Principal Coordinate Analysis (PCoA) revealed significant variations in microbiota species diversity between the fence and the retina/choroid. Interestingly, we detected 12 microbiota shared by the retina, choroid, and fence at the phylum level. Among these shared microbiotas, the relative abundance of Proteobacteria, Actinobacteria, Deinococcota, and TM7 decreases from the retina to choroid to feces, while the relative abundance of Firmicutes, Verrucomicrobia, and Planctomycetes increases in the same order.

Conclusions : The retina, choroid, and feces share many microbiotas under normal physiological conditions, suggesting a gut-eye axis of the microbiota. The pathophysiological role of these shared microbiotas in ocular health and disease remains to be elucidated.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

(A) The taxonomic composition of the genera. The most prevalent genera across fence(B), retina(C), choroids(D).

 

Alpha diversity: Observed(A) Shannon (B); (C) Principal Coordinate Analysis (PCoA); (D) Venn analysis; (E) The relative abundance of shared microbiota decreases from the retina to choroid to feces and increases in the same order.