Role of Soluble Epoxide Hydrolase in Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is a spectrum of liver disorders ranging from hepatic steatosis to steatohepatitis with varying degrees of fibrosis and cirrhosis. ALD is a major cause of morbidity, mortality, and health care costs in the US and worldwide. However, there is no FDA-approved therapy for any stage of ALD.

There is also an incomplete understanding of the mechanisms and mediators of disease progression and severity. Soluble epoxide hydrolase (s-EH), a master enzyme that regulates the metabolism of endogenous bioactive lipids (e.g., epoxy-fatty acids, Ep-FAs), has recently been recognized as an emerging therapeutic target

in multiple diseases. The overall goal of this project is to test the therapeutic efficacy of s-EH inhibition at different stages of ALD severity, and to provide a mechanistic foundation for using s-EH inhibition as a novel therapy for alcohol-induced liver pathology. Aim 1. To test the therapeutic effectiveness of s-EH inhibition

as a novel therapeutic strategy for ALD. We will: i) test whether modulation of s-EH activity by pharmacological inhibition or s-EH (Ephx2) genetic ablation can effectively attenuate or prevent EtOH-induced liver injury in experimental ALD; ii) evaluate whether s-EH inhibition leads to stabilization of blood and liver Ep-FAs; and iii)

correlate changes in Ep-FA levels with markers of liver injury. Systemic and targeted liver-specific delivery of s- EH inhibitors (t-TUCB and TPPU), and WT and Ephx2 -/- mice (global and liver-specific) will be used in multiple animal models of ALD, which produce different stages of disease severity and which recapitulate different

features of human ALD. This allows for a rigorous evaluation of the effects of s-EH inhibition at different stages of ALD severity. Treatment and prevention paradigms will be applied. Aim 2. To explore mechanism(s) underlying the beneficial effects of s-EH inhibition in experimental ALD. We will determine whether Ep-FA

stabilization mediated by s-EH inhibition plays a critical role in attenuation of EtOH-induced liver injury. We will test whether n3 vs n6 Ep-FAs exert a greater beneficial effect by enhancing M2 macrophage polarization, increasing a pro-restorative/pro-resolving macrophage phenotype, and by Ep-FAs-PPARγ-CXCL1-mediated

reduction of neutrophil infiltration. s-EH inhibitors, WT, transgenic fat-1 mice (which endogenously convert n6 PUFAs to n3 PUFAs), and hepatocyte-specific Pparγ-/- mice will be used. In vivo and in vitro studies will be performed. Aim 3. To evaluate EtOH-induced alterations in s-EH and Ep-FAs in human ALD. Utilizing de-

identified human plasma and whole blood samples, we will: i) evaluate alterations in plasma Ep-FAs and establish relationships between biomarkers of liver injury and systemic inflammation in patients with alcohol- associated hepatitis (AH); ii) determine the effects of n3-PUFA dietary supplementation on plasma Ep-FAs in

heavy drinking individuals; and iii) test whether s-EH inhibition and Ep-FAs (including both n3 and n6 Ep-FAs) can effectively decrease basal and LPS-stimulated pro-inflammatory cytokine production in whole blood and peripheral blood monocytes obtained from AH patients.