Date of Award

7-1-2020

Degree Name

Master of Science

Department

Biological Sciences

First Advisor

Dr. Cindy Linn

Second Advisor

Dr. John Spitsbergen

Third Advisor

Dr. Pamela Hoppe

Keywords

Progenitor cell, retina, molecular biology, transcription, gene expression

Access Setting

Masters Thesis-Open Access

Abstract

Previous studies from this lab have determined that dedifferentiation of Müller glia (MG) occurs after application of an α7 nicotinic acetylcholine receptor agonist, PNU-282987 (PNU), to retinal pigment epithelial (RPE) cells in adult rodents. This study was designed to explore the role of the HB-EGF/Ascl1/Lin28a signaling pathway in MG dedifferentiation to retinal progenitor cells. RNAseq was performed on MG following contact with RPE-J cells treated with PNU-282987. Up- or down-regulated genes were compared with published literature of MG dedifferentiation that occurs in lower vertebrate regeneration or with transcript profiles during early mammalian development. Between 8-12 hours, up-regulation was observed in gene HB-EGF and after 48 hours, up-regulation was found in Ascl1 and Lin28a, known to be rapidly induced in de-differentiating MG in zebrafish. Up-regulation was found in other factors known to be involved in mammalian development and zebrafish regeneration, and down-regulation in some factors necessary for MG differentiation. RNA-seq results were verified using qRT-PCR. Using immunocytochemistry, we were able to confirm the presence of retinal progenitor markers OTX2, Nestin and VSX2 in MG 48 hours post treatment with PNU-treated RPE supernatant. The results from this study will further our understanding of adult mammalian neurogenesis, will lead to new insights into typical mammalian neurogenesis limitations and provide potential strategies to treat neurodegenerative diseases.

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