Lipid Receptor GPR31 as a Target for Anti-Thrombotic and Stroke Therapy

Despite prevalent use of anti-platelet and anti-lipid therapies, stroke remains the third major cause of death and is the leading cause of adult disability in the US with an estimated cost in the range of $34 billion annually. Approximately 20% of the annual 795,000 stroke patients die within one year and 15-30% are permanently disabled. Antiplatelet therapy is mainly used for primary prevention of acute ischemic stroke in cerebrovascular disease. Bioactive fatty acids are a new class of molecular targets that hold great therapeutic potential because of their diverse role as signaling molecules that regulate metabolism and inflammation. The oxidation of arachidonic acid by 12-LOX results in the production of a number of bioactive lipids including the metabolite 12(S)-HETE. The lipid receptor GPR31, an orphan class A GPCR, is a 12(S)- HETE receptor recently shown to be involved in inflammatory signaling. We recently discovered that GPR31 mediates 12(S)-HETE prothrombotic signaling in platelets and promotes glutamate-induced oxidative toxicity in neuronal cells. Therefore, we propose that targeting GPR31 may provide a therapeutic path towards development of a safe and effective antiplatelet therapy that is coupled with secondary neuroprotective effects for mitigating against the acute neurologic sequela of stroke to provide a more effective and safer alternative option or adjunct to fibrinolytic therapy. We have recently succeeded in identifying the first effective GPR31 antagonist using our cell-penetrating, membrane-tethered, Pepducin technology to be validated in these preclinical IND-enabling studies as an anti-platelet and anti-stroke agent. We show here that this i3-loop derived GPR31 lipopeptide has potent antiplatelet activity and nearly completely suppresses arterial thrombosis without an effect on hemostasis in mice. Preliminary data with the GPR310 pepducin shows a highly significant reduction in stroke infarct area in mice similar to the protective effect of Gpr31-deficiency. Furthermore, we provide evidence for a direct neuroprotective effect of the GPR310 pepducin on HT22 neuronal cells subjected to glutamate mediated oxidative stress. The goal of this Phase 2 STTR project is to develop the GPR310 pepducin as a collaborative effort between Oasis Pharmaceuticals (Lexington, MA), Tufts Medical Center (Boston, MA) that would provide a robust IND data package required to advance the initial commercial development of the first GPR31 inhibitor as a dual antiplatelet, anti-stroke drug. This drug development program would establish the scientific merit of the GPR31 target by accomplishing the major milestones at the end of 2 years of GLP safety/pharmacology and efficacy in stroke models ± thrombolytic therapy to support a Phase I first-in-human clinical trial.