Targeting the GDF15-GFRAL system to treat nausea and emesis

摘要 生长分化因子15(GDF15)，以前称为巨噬细胞抑制细胞因子-1(MIC-1)， 是一种细胞因子，表现出对许多条件和疾病的反应和血清的升高，包括 怀孕、肥胖、糖尿病和癌症。GDF15信号在最近几年得到了极大的关注 2017年发表的多篇论文确定GDNF家族受体α样受体与GDF15结合 选择性和高亲和力。然而，已报道的GFral受体对 脑干的最后区(AP)和孤束核(NTS)，这两个区域对这两种能量都非常关键 平衡和呕吐/恶心/乏力提示GDF15-GFERAL信号可能不仅是一个重要因素 在长期的体重调节中，也在短期内处理呕吐和疾病。行为。因此， 了解GDF15-GFral信号在疾病行为和厌食症中的作用至关重要 确定GDF15的作用机制。令人信服的证据将GDF15信号与化疗联系起来- 诱发性恶心和厌食症，尽管控制相对较好，但仍是重要的临床问题 化疗诱导的呕吐，表明：1)GDF15信号导致恶心和呕吐；2)AP/NTS 作用部位负责通过与GDF15结合来介导GDF15信号的摄食效应。 RET受体复合体，以及3)肥胖、癌症和化疗增加了啮齿动物循环中的GDF15和 人类。我们假设NTS中央GDF15表达的功能动态变化 在能量平衡失调和/或给予呕吐刺激后会发生AP，我们 可以通过独特的分子和行为分析以及基于专利的多肽来缓解/治疗这种情况 这里使用的技术(即我们的 基于多肽的 抑制者 绑定 恶心 新型GFRAL-RET拮抗剂(“GRAPH”)。GRAPH拮抗器是一种小型、 我们的体内和构象结合模型支持它是变构的序列 到GFra-RET复合体。我们还证明了GRAP可以穿透到脑干和 ，从而减弱GDF15和顺铂诱导的GDF15表达 为了进一步探索GDF15-GFRAL系统，我们建议通过一项补充研究 由具有丰富协作经验的成熟调查人员组成的多PI团队调查以下事项 目的：目的研究内源性GDF15的脑干回路和无偏向单细胞转录产物 神经细胞的产生和表达GFra/RET的神经细胞表型。AIM II将描述GDF15诱导的呕吐， 恶心行为和厌食症，以及表征抓握先导化合物针对这些行为 多物种方法。目标III将描述GRACH的关键机械参数和稳定性参数 通过基于功能、计算和结构数据的合理模拟设计，以我们的 到目前为止，寻求阻断GFra受体以治疗疾病的成功技术包括 不受欢迎的厌食症、恶心和呕吐。

Summary The growth differentiation factor 15 (GDF15), formerly known as macrophage inhibitory cytokine-1 (MIC-1), is a cytokine that shows expression and serum rise in response to many conditions and diseases, including pregnancy, obesity, diabetes, and cancer. GDF15 signaling has gained significant attention in recent years with multiple papers in 2017 identifying the GDNF family receptor α-like ( GFRAL ) receptor as binding GDF15 selectivelyand with high affinity. However, the reported restrictive expression of the GFRAL receptor to the area postrema (AP) and nucleus tractus solitarius (NTS) of the brainstem, areas highly critical to both energy balance and emesis/nausea/malaise suggests that GDF15-GFRAL signaling could be an important factor not only in long-term body weight regulation, but also in short-term processing of emesis and illness. Behavior. Thus, understanding what role GDF15-GFRAL signaling plays in illness behavior and anorexia is paramount to determining the mechanism of GDF15 action. Compelling evidence links GDF15 signaling with chemotherapy- induced nausea and anorexia, which remain important clinical problems despite relatively well-controlled chemotherapy-induced emesis, by showing that: 1) GDF15 signaling causes nausea and emesis; 2) an AP/NTS site of action is responsible for mediating the feeding effects of GDF15 signaling through binding of the GFRAL- RET receptor complex, and 3) obesity, cancer, and chemotherapy increase circulating GDF15 in rodents and humans. We hypothesize that a functional dynamic change in the expression of central GDF15 levels in the NTS and AP will occur following energy balance dysregulation and/or administration of emetic stimuli, and that we can mitigate/treat such through the unique molecular and behavioral assays and patented peptide-based technology employed here (i.e. our peptide-based inhibitor bind nausea novel GFRAL-RET antagonist “GRASP”). The GRASP antagonist is a small, sequence with our in vivo and conformational binding models supporting it to be an allosteric to the GFRAL-RET complex. We have also shown that GRASP can penetrate into the brainstem and to GFRAL-expressing neurons in the AP/NTS, and consequently attenuate GDF15- and cisplatin-induced behaviors in rats.To further explore the GDF15-GFRAL system, we propose complimentary studies by a multi-PI team of established investigators with extensive collaborative experience to investigate the following aims: Aim I will characterize brainstem circuitry and unbiased single cell transcriptomics for endogenous GDF15 production and GFRAL/RET-expressing neuronal phenotypes. Aim II will characterize GDF15-induced emesis, nausea behavior, and anorexia as well as characterize the GRASP lead compound against these behaviors with a multi-species approach. Aim III will characterize the critical mechanistic and stability parameters of GRASP through rational design of analogs based on functional, computational and structural data to build upon our successful technology to-date that seeks to block the GFRAL receptor to treat sickness measures that include unwanted anorexia, nausea and emesis.