Abstract
Presentation Description :
Retinal Müller glia show dramatic differences in neurogenic competence among different species. Zebrafish Müller glia have an extraordinary capacity to regenerate retinal neurons; a majority of retinal neurons can be destroyed, and within a few weeks the retina is re-populated with functional neurons and visual function restored. Chick Müller glia are capable of producing proliferating progenitor cells, but these Müller glia-derived progenitor cells (MGPCs) have a limited capacity to generate new neurons in vivo. In contrast, the rodent Müller glia only inefficiently produce MGPCs following injury that have very limited neurogenic competence, and lose this ability entirely after infancy. We hypothesize that differences in transcriptional regulation drive regeneration in the fish, limit regeneration in the chick, and suppress regeneration in mammals. To test this hypothesis, we FACS-purified GFP-positive Müller glia and GFP-negative neuronal fractions and then performed bulk RNAseq and ATACseq at multiple time points under two different damage paradigms (light damage and NMDA damage) in all three organisms. Additionally, we performed single-cell RNAseq in all three organisms in both damage models at the same time points. We undertook a comparative analysis of these different datasets to identify similarities and differences in the Müller glia gene expression profiles to identify: 1. similarities and differences in zebrafish Müller glia gene expression in the two different damage models to identify general Müller glia reprogramming changes and damage-specific changes, 2. similarities and differences in Müller glia gene expression between the three model organisms that may correspond to differences in how the Müller glia respond to retinal damage in each organism. Using these approaches, we identified several novel candidate genes that may be involved in the permissive Müller glia reprogramming and regeneration response in zebrafish. Using morpholino-mediated protein knockdown, we tested the roles of the candidate genes/proteins in Müller glia reprogramming in the damaged zebrafish retina. Further, we tested the roles of some of these candidates in the damaged mouse retina. We will discuss the comparative analysis of the expression and chromatin data, as well as the functional testing of candidates.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.