Neural Mechanisms of Nausea, Vomiting, and Energy Dysregulation

项目总结

Project Summary Nausea and vomiting promote mammalian survival. Paradoxically, emetic “side effects” are ubiquitously reported for FDA-approved pharmacotherapeutics for obesity, diabetes, and cancer pharmacotherapies and present alongside polymorbidities that contribute to detrimental life-threatening outcomes, such as poor nutrition, quality of life, and patient prognosis. Here, we address two broad unmet clinical needs: 1) All existing FDA-approved glucagon-like peptide-1 (GLP-1)-based therapeutics for the treatment of diabetes and obesity elicit nausea and vomiting in a significant percentage of patients. 2) Despite existing antiemetic treatments available, virtually all patients undergoing chemotherapy continue to exhibit profound debilitating symptoms, such as severe nausea, vomiting, and cachexia. We use modern behavioral and neurogenetic approaches, and appropriate, comparative, preclinical animal models that are critical to produce novel, effective, long-term controls of nausea and vomiting to advance modern metabolic health care. Intestinally derived GIP regulates postprandial glucose through direct action on GIP receptors (GIPR) expressed on pancreatic beta cells. GIP analog efficacy as a monotreatment of diabetes and obesity is at best limited and controversial, however, the expression of CNS GIPRs in regions implicated in nausea/emesis have spawned investigation of central actions of GIP ligands as potential adjunct therapeutics to reduce unwanted adverse events. Specifically, our data support that GIPR and GLP-1R dual agonism provide body weight loss, hypophagia, and glucoregulatory control without nausea and emesis, compared to GLP-1R agonism alone, through activation of the GIP system. The area postrema (AP) and nucleus tractus solitarius (NTS) of the dorsal vagal complex (DVC) play a critical role in ingestive behavior, emesis, and nausea. Widely used emetogenic chemotherapeutics (e.g., cisplatin) and all FDA- approved GLP-1-based ligands activate AP/NTS neurons. Our collective works suggest hindbrain GIPRs block nausea and vomiting induced by GLP-1R and cisplatin chemotherapy in several animal species, suggesting translational broad-spectrum antiemetic potential for GIPR agonists. We have identified cellular phenotypes of AP/NTS GIPR- and GLP-1R- expressing cells, as well as shown the attenuation in AP/NTS neuron activity, and preliminary data). Additionally, we have discovered a molecularly distinct GABA-ergic neuronal DVC population that is modulated by chemotherapy but rescued by GIPR agonism. We hypothesize that there exists an antiemetic system characterized by inhibitory (i.e., GABA-ergic) neurons expressing GIP receptors (GIPR). Here, we will: Aim I: Examine behavioral, anatomical, and transcriptomic mechanisms by which GIPR-GABA+ AP/NTS neurons exhibit antiemetic action. Aim II: Examine GIP antiemetic action in conjunction with established antiemetics using a multi-species approach. Our data in multiple species all indicate that GIP agonism has an antiemetic effect and here we use our unique multi-species approach to define the mechanisms of the GIP system in reducing and/or preventing therapeutic drug-induced nausea and emesis.