Neurobiology for Lac-Phe Hypophagia

项目总结 有规律的体育锻炼是一种有效的干预措施，可以减少肥胖，防止肥胖。 肥胖相关的代谢性疾病。责任机制尚不完全清楚，但很有可能 扩大到仅与活动相关的能源支出增加。我们最近发现了一种 乳酸衍生的代谢物N-乳酰-苯丙氨酸(“Lac-Phe”)是最显著升高的 剧烈运动后血浆中的代谢物。我们进一步证明了药理上的 提高血浆Lac-Phe水平以模拟运动训练可以有力地抑制肥胖小鼠的摄食，并且 反复服用Lac-Phe方案可导致慢性吞噬功能低下、体重减轻和肥胖减少，与 改善了糖耐量。虽然这些发现增加了Lac-Phe可能被用作 作为抗肥胖剂，Lac-Phe低噬的神经生物学机制尚不清楚。我们的 初步研究发现，豚鼠弓状核内有AgRP阳性神经元。 下丘脑(ARH)作为Lac-Phe作用的直接靶点，介导其低噬反应。一 目的：观察Lac-Phe和运动对AgRP神经元传入突触的影响。 AgRP神经元向其突触靶点的传出输出。我们的数据还表明，Lac-Phe抑制了 通过增加外向钾电流，即KATP电流，产生食欲性AgRP神经元。因此，第二个 目的是利用CRISPR-Cas9方法从基因上干扰KATP通道亚单位的表达。 AgRP神经元，并利用这些模型来确定KATP通道在Lac-Phe诱导中的功能相关性 AgRP抑制和吞噬功能低下。最后，我们还观察到，Lac-Phe激活了另外四个大脑中的神经元 脑区、外侧隔核、下丘脑室旁核、臂旁核 核团(PBN)和孤束核(NTS)。因此，我们将把定向重组结合到 电生理学、化学遗传学和scRNA-Seq结合的活性群体(TRAP)方法 Lac-Phe是否直接或间接刺激这些神经元，这些神经元是否在功能上参与 这些被Lac-Phe激活的神经元的神经化学特征是什么？ 这些拟议的实验将揭示Lac-Phe低吞噬症的神经生物学基础，这可能会识别 Lac-Phe或相关途径作为体重管理的目标。

PROJECT SUMMARY Regular physical activity is a powerful intervention that reduces obesity and confers protection against obesity-associated metabolic diseases. The mechanisms responsible are incompletely understood but are likely to extend beyond activity-associated increases in energy expenditure alone. We recently identified a lactate-derived metabolite called N-lactoyl-phenylalanine (“Lac-Phe”) as the most significantly elevated metabolite in blood plasma after an intense exercise bout. We further demonstrated that pharmacological elevation of plasma Lac-Phe to mimic exercise training can robustly suppress feeding in obese mice, and repeated Lac-Phe regimen results in chronic hypophagia, weight loss, and reduced adiposity, associated with improved glucose tolerance. While these findings raise the possibility that Lac-Phe could be used as an anti-obesity agent, the neurobiological mechanisms underlying Lac-Phe hypophagia remains unknown. Our preliminary studies identified Agouti-related peptide (AgRP)-expressing neurons in the arcuate nucleus of the hypothalamus (ARH) as one direct target of Lac-Phe action and mediate its hypophagic response. One objective is to examine effects of Lac-Phe and exercise on afferent synaptic inputs to AgRP neurons, and efferent outputs from AgRP neurons to their synaptic targets. Our data also suggest that Lac-Phe inhibits orexigenic AgRP neurons via increasing an outward potassium current, namely KATP current. Thus, the second objective is to use the CRISPR-Cas9 approach to genetically disrupt the expression of KATP channel subunits in AgRP neurons, and use these models to determine the functional relevance of KATP channel in Lac-Phe-induced AgRP inhibition and hypophagia. Finally, we also observed that Lac-Phe activates neurons in four other brain regions, the lateral septum (LS), the paraventricular nucleus of the hypothalamus (PVH), the parabrachial nucleus (PBN), and the nucleus of solitary tract (NTS). Thus, we will combine the Targeted Recombination in Active Populations (TRAP) approach with electrophysiology, chemogenetics and scRNA-Seq to determine whether Lac-Phe stimulates these neurons directly or indirectly, whether these neurons functionally participate in the Lac-Phe-induced hypophagia, and what are neurochemical identities of these Lac-Phe-activated neurons. These proposed experiments will reveal the neurobiological basis for Lac-Phe hypophagia, which may identify Lac-Phe or the associated pathways as targets for weight management.