Analysis of cell‐type restricted transcriptional networks in human photoreceptor neurons

Abstract

The retina is a layered neuronal tissue lining the posterior portion of the eye that converts photons of light into visual images in the brain. Rod and cone photoreceptors are highly specialized light sensitive neurons that initiate this process of phototransduction. Though they are similar cell types, rods and cones have distinct functionalities, synaptic connections, and are affected by different blinding disease alleles. In order to characterize cell‐type specific transcriptional networks in human photoreceptors, rod and cone‐enriched samples were biopsied from the eyes of 7 post‐mortem human donors. Total RNAs were extracted from retinal samples using a Qiagen AllPrep Mini Kit. High quality RNAs were prepared into cDNA libraries representing cellular mRNAs and sequenced using an Illumina NextSeq 500 sequencer. Sequencing reads were assessed, trimmed and visualized using FastQC, Trimmomatic, and MultiQC softwares respectively. High quality reads were then aligned to the human hg38 reference transcriptome using the high speed pseudoaligner Kallisto. The sleuth statistical model and RStudio package was used to quantify read alignments and calculate differentially expressed transcripts (DETs) between rod and cone‐enriched sample groups. These analyses identified 10,875 DETs between sample groups with a FDR adjusted p‐value ≤0.05. Of these DETs, 4,365 are transcribed at higher levels in rod‐enriched retinal tissue while 6,519 demonstrate increased transcription in the cone‐enriched retina. We are currently testing the hypothesis that differential patterns of DNA methylation contribute to cell‐type restricted transcription in photoreceptor neurons. These data will contribute to a better understanding of epigenetic regulation of gene expression networks in the human retina.Support or Funding InformationThis research is supported by a JMU 4‐VA Collaborative Research Grant, Burroughs Wellcome Fund Grant #1017506, and NIH grant #1 R15 EY028725‐01A1 awarded to RAE.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.