Date Published: April 19, 2019
Publisher: Public Library of Science
Author(s): William C. Reisdorf, Qing Xie, Xin Zeng, Wensheng Xie, Neetu Rajpal, Bao Hoang, Mark E. Burgert, Vinod Kumar, Mark R. Hurle, Deepak K. Rajpal, Sarah O’Donnell, Thomas T. MacDonald, Anna Vossenkämper, Lin Wang, Mike Reilly, Bart J. Votta, Yolanda Sanchez, Pankaj Agarwal, Fulvio D’Acquisto.
Epoxyeicosatrienoic acids (EETs) are signaling lipids produced by cytochrome P450 epoxygenation of arachidonic acid, which are metabolized by EPHX2 (epoxide hydrolase 2, alias soluble epoxide hydrolase or sEH). EETs have pleiotropic effects, including anti-inflammatory activity. Using a Connectivity Map (CMAP) approach, we identified an inverse-correlation between an exemplar EPHX2 inhibitor (EPHX2i) compound response and an inflammatory bowel disease patient-derived signature. To validate the gene-disease link, we tested a pre-clinical tool EPHX2i (GSK1910364) in a mouse disease model, where it showed improved outcomes comparable to or better than the positive control Cyclosporin A. Up-regulation of cytoprotective genes and down-regulation of proinflammatory cytokine production were observed in colon samples obtained from EPHX2i-treated mice. Follow-up immunohistochemistry analysis verified the presence of EPHX2 protein in infiltrated immune cells from Crohn’s patient tissue biopsies. We further demonstrated that GSK2256294, a clinical EPHX2i, reduced the production of IL2, IL12p70, IL10 and TNFα in both ulcerative colitis and Crohn’s disease patient-derived explant cultures. Interestingly, GSK2256294 reduced IL4 and IFNγ in ulcerative colitis, and IL1β in Crohn’s disease specifically, suggesting potential differential effects of GSK2256294 in these two diseases. Taken together, these findings suggest a novel therapeutic use of EPHX2 inhibition for IBD.
Ulcerative colitis (UC) and Crohn’s disease (CD)–the major types of inflammatory bowel disease (IBD)—are immunologically mediated chronic diseases that affect some 1–2 million people each in the US and Europe . Both UC and CD are progressive diseases, with periods of remission and relapse. While the inflammation in UC is confined to the large intestine, and affects the mucosa in a continuous fashion, in CD inflammation is usually confined to the ileum and cecum and is typically transmural. Clinical symptoms presented by both diseases include diarrhea, fever, fatigue, abdominal cramping, bloody stools, reduced appetite and weight loss. Current standard of care often involves several rounds of treatment (further discussed below) as well as hospitalization, with eventual surgery, when existing medications become ineffective and/or not tolerated. This creates significant social and productivity burdens which adversely impact the patient’s quality of life.
Our research efforts added to emerging evidence strongly point to the potential therapeutic benefits of inhibiting EPHX2 in IBD patients. Ex vivo measurements in colon tissue biopsies obtained from IBD patients showed that EPHX2 inhibition can decrease secretion of proinflammatory cytokines. A recent study showed that EETs concentrations were higher in UC tissues compared to matched adjacent non-inflamed tissue . UC tissues also showed reduced EPHX2 expression and increased CYP2J2 levels, both of which would lead to increased EETs, as was observed. The relative EPHX2 expression in disease vs. normal seems to differ between our observations and those of Qiu et al , which might be explained by the relatively small number of samples analyzed in both studies. Differences in disease stage may also be a factor, since our samples were derived from routine endoscopy, as opposed to colectomy surgery. It is tempting to speculate that an up-regulation of EETs is a physiological response to contain inflammation, and that this protective mechanism may be impacted by disease progression.