Indiana University School of Medicine
Indianapolis, Indiana

JOE M. & EULA C. LAWRENCE RESEARCH PROJECT
Localization and lipid modulation of soluble epoxide hydrolase in choroidal neovascularization

The long-term goal is to find new therapeutic approaches for ocular neovascularization, the abnormal blood vessel growth seen in diseases like wet age-related macular degeneration.

Plans for 2021
The specific goal of the current grant period is to explore soluble epoxide hydrolase (sEH), an enzyme Dr. Corson’s research team identified to be important for abnormal new blood vessel growth.  The laboratory will definitively determine which cell types in the eye produce sEH and ascertain the effect on fatty acids when it is depleted, to guide therapeutic development. Specifically, they will determine exactly which cells in the eye express sEH , and how sEH loss in the eye changes the levels of various lipids (fats);  Previously the team saw sEH protein in light-sensing cells of the retina, but others have observed it in other cell types.  Dr. Corson will use a new technique called RNAscope to unambiguously show the retinal cell types producing sEH.  Using “lipidomics” that allow the team to assess many molecules at once, they will also determine how lipids are altered when sEH is reduced using a genetic tool.

Specific Aims: Aim 1. Examine the spatial pattern of Ephx2 mRNA expression in the retina during choroidal neovascularization (CNV). Aim 2. Determine sEH-modulated lipid metabolites in L-CNV.

Progress in 2020
Effects of sex differences in soluble epoxide hydrolase expression on choroidal neovascularization

The specific goal of the 2020 project was to understand how the levels of soluble epoxide hydrolase (sEH), an enzyme identified to be important for abnormal new blood vessel growth, differ between the sexes, and how this influences the therapeutic effectiveness of sEH inhibitors.

Specific Aims: Aim 1: Examine sex differences in sEH expression and pharmacological response to sEH inhibitors. In a pilot study, male mice exhibited higher sEH expression in their eyes than females leading to the postulation that sex-specific expression of sEH could lead to differential response to sEH inhibition for new blood vessel growth.  Dr. Corson’s laboratory will assess the effects of sex differences in sEH expression on the therapeutic effects of sEH inhibition by genetic and chemical means.  They will explore downstream signaling in response to sEH inhibition.

In previous years of RRF funded projects, Dr. Corson’s team developed a potent chemical called SH-11037, and tested it in combination with standard anti-VEGF therapy.  They found sEH as a cellular target of SH-11037, and showed that sEH is present at high levels in human and mouse eyes with AMD-like features.  They found that known sEH inhibitors can block new blood vessel growth in the eye and they characterized the molecular mechanism of how SH-11037 inhibits sEH, including identifying factors that increase its levels in the eye.  Assessing their library of novel chemicals, they found candidates that perform as well as SH-11037 at blocking sEH, helping to build a “structure activity relationship” for blocking sEH function.  During 2020, Dr. Corson’s team showed differential expression in sEH between the sexes, and found that depletion of sEH with a genetic tool they developed reduces inflammatory signals.

2020 Publications

Progress in 2019
Characterization of soluble expoxide hydrolase as a marker of choroidal neovascularization

 A major avenue for the treatment of diseases such as retinopathy of prematurity (ROP), proliferative diabetic retinopathy and wet age-related macular degeneration (AMD) is to stop the growth of new blood vessels in the eye, and there is a critical need to find new targets that could be effective in treating these blinding eye diseases.  Dr. Corson studies the mechanisms of a class of molecules called homoisoflavonoids, derived from medicinal plants, with potent effects on blocking blood vessel growth in mouse models of AMD and ROP.

His goal in 2019 was to find the cellular factors that promote high levels of sEH in new blood vessel growth in humans and mice. Dr. Corson’s work showed that sEH can be induced by cellular factors like stress, low oxygen levels, and high glucose known to be associated with eye disease, and in human wet AMD, that the light-sensing and pigmented cells of the retina increase sEH.   His research revealed that known sEH inhibitors can block new blood vessel growth in the eye, and his team characterized the molecular mechanism of the process.

Specific Aim: 1. Define factors that induce sEH overexpression in neovascularization. The working hypothesis for this aim is that proangiogenic stimuli – VEGF-A, TNF-α, endoplasmic reticulum (ER) stress and/or hypoxia – will enhance the expression and activity of sEH in photoreceptor cells, retinal pigment epithelial cells, and/or retinal and choroidal endothelial cells. sEH levels in treated cells will be assessed by qRTPCR and immunoblot, followed by sEH activity assays and luciferase assays. In addition, we will determine which retinal cell types in human eyes express sEH under normal and wet AMD conditions by co-immunostaining human sections with retinal cell type markers.

Progress in 2018
Screening homoisoflavonoids as soluble epoxide inhibitors for choroidal neovascularization

In prior years of RRF funding, Dr. Corson developed a potent chemical called SH-11037, and tested this in combination with anti-VEGF therapy. We found sEH as a cellular target of SH-11037, and showed that sEH is present at high levels in human and mouse eyes with AMD-like features. We found that known sEH inhibitors can block new blood vessel growth in the eye, that a substrate (input) of sEH was antiangiogenic, and we characterized the molecular mechanism of how SH-11037 inhibits sEH. In 2018, we assessed our library of novel chemicals and found candidates that perform as well as SH-11037 at blocking sEH, helping to build a “structure activity relationship” for blocking sEH function.

Progress in 2017
Role of epoxy lipid metabolism in choroidal neovascularization

Dr. Corson previously developed a potent “homoisoflavonoid” chemical called SH-11037, and tested this in combination with anti-VEGF therapy. His team found sEH as a cellular target of SH-11037, and showed that sEH is present at high levels in human and mouse eyes with AMD-like features. In 2017, they showed that a substrate (input) of sEH was antiangiogenic, characterized the molecular mechanism of how SH11037 inhibits sEH, showed this inhibition occurs in eye tissue, confirmed that the rod photoreceptor cells are the site of increased sEH in eyes undergoing angiogenesis, and found that known sEH inhibitors can block new blood vessel growth in the eye.

Progress in 2016
“Soluble epoxide hydrolase: a therapeutic target in choroidal neovascularization?”

Homoisoflavonoids are a small class of natural products that Dr. Corson has pursued as antiangiogenic leads. In particular, he focused on a target of SH-11037 that he identified, soluble epoxide hydrolase (sEH), hypothesizing that sEH is required for choroidal neovascularization. He has completed the Aim 1 of assessing sEH expression in murine and human choroidal neovascularization, and most of Aim 2, inhibiting sEH in the context of choroidal neovascularization. It will be important to determine what aspects of sEH function are important for blood vessel growth, and how this enzyme is linked to signaling in the cell.  This work will lay the groundwork for future efforts to target sEH for the treatment of wet AMD and related retinal diseases of abnormal blood vessel growth.

Progress in 2015
“Synergistic effects of a novel antiangiogenic molecule”

Dr. Corson’s laboratory tested their most potent synthetic homoisoflavanone, SH-11037, in combination with anti-VEGF therapy. It showed efficacy comparable to the standard anti-VEGF treatment in the laser-induced choroidal neovascularization (L-CNV) mouse model, which models some of the features of wet AMD. SH-11037 could synergize with anti-VEGF, reducing the amount of each drug needed for an effect. Importantly, they saw no short-or long-term toxicity in the eyes of adult mice with SH-11037 injected into their eyes. They have begun to tease apart how SH-11037 works to block blood vessel growth, and have identified an enzyme called soluble epoxide hydrolase (sEH) as a target of SH-11037. It will be important to assess if sEH is found at high levels in CNV, and if blocking its function can decrease L-CNV.

Progress in 2014
“Testing a novel Antiangiogenic molecule in a mouse model of retinopathy of prematurity”

Dr. Corson further investigated a class of natural products, homoisoflavonoids, as antiangiogenic molecules. He synthesized a naturally occurring, antiangiogenic homoisoflavanone called Cremastranone derived from a medicinal orchid species and a novel isomer, both of which showed antiangiogenic activity in vitro.  He has tested a novel, more potent derivative of Cremastranone called SH-11037 in the oxygen-induced retinopathy (OIR) model of ROP. It showed efficacy comparable to the standard anti-VEGF treatment. Importantly, he saw no short- or long-term toxicity in the eyes of adult mice intravitreally injected with SH-11037, and the compound was also effective in the laser-induced choroidal neovascularization (L-CNV) mouse model. Dr. Corson has begun to tease apart how SH-11037 works to block blood vessel growth.

Progress in 2013
“Cellular target of a candidate AMD therapy”

Dr. Corson investigated a class of natural products, homoisoflavonoids, as antiangiogenic molecules. He synthesized a novel isomer (SH-11052) of a naturally occurring, antiangiogenic homoisoflavanone derived from a medicinal orchid species and showed Antiangiogenic activity of SH-11052 in vitro. In the course of these studies, Dr. Corson’s laboratory developed a compound SH-11037, a novel therapeutic lead based on the natural product, but with improved efficacy and specificity. SH-11037 potently and specifically blocks human retinal microvascular endothelial cell (HRMVEC) proliferation, migration, and tube formation in vitro by a molecular mechanism distinct from other homoisoflavonoids, but has little cytotoxic effect on other ocular cell lines and does not promote apoptosis. In a small pilot experiment, SH-11037 showed antiangiogenic activity in the oxygen-induced retinopathy (OIR) model of ROP.