Exploring the angiogenesis-to-fibrosis transition in ischemic retinopathies Renewal

Diabetic retinopathy (DR) and other forms of retinal ischemia are a leading cause of blindness in working age adults. There is a need to identify the mechanisms underlying the transition from angiogenesis to fibrosis in these conditions, as a first step towards new therapies to address progressive retinal vascular damage that ultimately leads to pre-retinal fibrosis and traction detachment with poor visual and anatomic outcomes. To address this gap in our knowledge, we have designed a series of experiments that build logically on our preliminary data which shows robust evidence for pericyte involvement in fibrovascular tissues, and the potential markers. We have optimized the timepoints for examining their role in a mouse model of ischemia induced retinal fibrosis and optimized the relevant fate tracing transgenic mouse. To examine this hypothesis, we will study animal models that focus on developmental ischemia- the oxygen induced retinopathy (OIR, to replicate angiogenesis in ischemia) and the limited hyperoxia-induced proliferative retinopathy (LHIPR), which replicates the angiofibrotic end- stages of severe ischemia. We will use these models and ground our results in human donor eye studies, to test the hypothesis that the entire retinal transcriptome and epigenome is dysregulated during retinal fibrosis and identify targets for therapy. We will use a combination of single cell, high throughput sequencing and data analysis. We will also examine the fibrosis effectors directly by using genetic fate tracing. We will then use viral delivery of therapies to identify molecules that are necessary and sufficient for the transition to retinal fibrosis as these can be critical targets for human translational applications. The mechanistic experiments proposed herein will capitalize on the interdisciplinary expertise of the clinician-scientist PI (Dr. Fawzi) a clinician-scientist retina surgeon with special expertise in non-invasive retinal imaging, animal models of ischemia and retinal vascular diseases. Her co- investigator, Dr. Zhu, is a world-class expert in developing advanced tools for viral-mediated delivery, and Dr. Goyal an expert in analyzing high throughput complex multi-omic dataset. The strength of the preliminary data and team ensure the success this highly innovative proposal that addresses an unmet need in our field.