■Speaker■

Prof. Katia Del Rio-Tsonis

Dr. Del Rio-Tsonis obtained her BS degree from the University of California San Diego (UCSD) and her PhD from the National University of Mexico. She did her Post-doctoral work on newt lens regeneration at the University of Dayton and then transitioned to Miami University where she is currently a Professor in Biology and Co-director of the Center for Visual Sciences. Dr. Del Rio-Tsonis has been funded from the National Eye Institute (NEI) for over 20 years and has participated as a grant reviewer for the Center for Scientific Review for many years, and served in the National Advisory Eye Council. She has published over 90 peer reviewed articles and reviews. For several decades, her lab has focused on uncovering the mechanisms that control stem cell activation and tissue reprogramming studying the lens and the retina of the eye using animal models with high regenerative capabilities such as salamanders and embryonic chickens. Her lab has pinpointed key factors that induce chick neural retina regeneration such as the immune regulator and complement component C3a as well as the epigenetic modifier Tet3 and identified factors that limit neurocompetence such as OTX2 and NR2F1/2. She has also uncovered that macrophages are essential in the newt for scar–free lens regeneration. Most recently, her focus is on determining the gene regulatory network and epigenetic underpinnings that dictate pigmented tissues of the eye to be plastic and reprogram to either neural retina or lens.

■Abstract■

Understanding the regenerative powers of ocular pigment epithelium

Pigmented eye tissues such as the retinal pigment epithelium (RPE) or iris pigment epithelium (IPE) are not only key tissues responsible for eye function, but they also possess regenerative powers in certain animals. Newts can regenerate their lens and retina at any stage of their lives via pigment epithelial cell transdifferentiation. Newt IPE transdifferentiation to lens cells is restricted to the dorsal, but not the ventral, iris. We are using bulk and single-cell RNAseq, spatial transcriptomics, and optical coherence tomography (OCT) imaging to understand the molecular basis of regional restrictions in IPE cell regenerative competence and to delineate regional patterns in gene expression. We identified a highly conserved dorsal-ventral patterning axis associated with vertebrate eye development that persists across the newt iris into adulthood. Furthermore, upon lentectomy, we observed the emergence of a robust immune response gene signature and identified macrophages as key players in the regenerative outcome. We also use the embryonic chick eye to query mechanisms of RPE neural reprogramming. There is a small developmental window in which the chick eye can regenerate its retina via RPE transdifferentiation. Using multiomic approaches we are building a gene regulatory network that explains these regenerative abilities.