Role of PEDF/ATGL signalling in the central control of energy homeostasis

在中枢神经系统中，下丘脑通过整合循环代谢和激素信号，在调节能量摄入和消耗方面发挥关键作用。这些信号直接调节下丘脑神经元的活动，以协调适当的行为和生理反应，以维持能量平衡。脂肪酸(FA)在下丘脑细胞中起调节摄食和葡萄糖稳态的作用。然而，其中涉及的机制仍然难以捉摸。除了循环脂肪酸外，从细胞内甘油三酯(TG)储存中产生FA的中性甘油脂肪酶在调节能量平衡中的作用尚未被探索。*我们研究计划的主要目标是确定神经元脂肪甘油三酯脂肪酶(ATGL)在下丘脑能量平衡控制中的作用。ATGL是一种关键的细胞内酶，催化周围组织甘油三酯水解的第一步。此外，我们将研究色素上皮源性因子(PEDF)是否在下丘脑中作为能量充足的信号，通过神经元ATGL来维持能量平衡。PEDF是一种循环脂肪因子，通过ATGL调节周围组织的脂肪代谢。基于有希望的初步发现支持下丘脑神经元中的PEDF-ATGL信号在能量平衡控制中起关键作用这一新概念，我们建议1-研究中枢PEDF对能量稳态的影响，鉴定PEDF激活的下丘脑神经元网络并表征脑中ATGL的区域和细胞表达模式，2-利用有针对性的神经元ATGL功能丧失策略和ATGL的药理抑制来确定神经元下丘脑ATGL对能量稳态的作用和PEDF的中枢效应，以及，3-确定PEDF通过ATGL在下丘脑神经元中调制的信号和代谢通路的特征，并使用脂质组学识别由PEDF-ATGL通路产生的脂质衍生信号，并识别潜在的下游靶点。*中性甘油脂肪酶在细胞生理学和信号转导的基本方面的作用越来越被认识到。然而，它们在神经元FA信号和能量平衡控制中的作用仍不清楚。因此，该研究计划将为下丘脑神经元中ATGL的基础作用和通过PEDF-ATGL通路的信号传递及其在神经元能量稳态调节中的作用提供重要的见解。通过结合分子和细胞方面以及综合模型来研究小鼠的代谢生理学和神经回路，我们的计划将提供高水平的、多学科的HQP培训。

In the central nervous system, the hypothalamus plays a key role in regulating energy intake and expenditure by integrating circulating metabolic and hormonal signals. These signals directly modulate the activity of hypothalamic neurons to coordinate appropriate behavioural and physiological responses to maintain energy homeostasis. Fatty acids (FA) act in hypothalamic cells to regulate feeding and glucose homeostasis. However, the mechanisms involved remain elusive. Besides circulating FA, the role of neutral glycerolipid lipases that generate FA from intracellular triglycerides (TG) stores in the regulation of energy balance has not been explored. *** The main objective of our research program is to characterize the role of neuronal Adipose Triglyceride Lipase (ATGL), a key intracellular enzyme catalyzing the first and committed step of TG hydrolysis in peripheral tissues, in the hypothalamic control of energy homeostasis. In addition, we will investigate if Pigment Epithelium-Derived Factor (PEDF), a circulating adipokine that regulates lipid metabolism in peripheral tissues via ATGL, acts in the hypothalamus as a signal of energy sufficiency to maintain energy balance via neuronal ATGL. Based on promising preliminary findings supporting the novel concept that PEDF-ATGL signalling in hypothalamic neurons plays a key role in the control of energy balance, we propose to 1-investigate the impact of central PEDF on energy homeostasis, identify PEDF-activated hypothalamic neuronal networks and characterize the regional and cellular expression pattern of ATGL in the brain, 2-determine the role of neuronal hypothalamic ATGL on energy homeostasis and central effects of PEDF using a targeted neuronal ATGL loss-of-function strategy and pharmacological inhibition of ATGL and, 3- characterize the signalling and metabolic pathways modulated by PEDF via ATGL in hypothalamic neurons and identify lipid-derived signals generated by the PEDF-ATGL pathway using lipidomics and identify potential downstream targets. ***The role of neutral glycerolipid lipases in fundamental aspects of cell physiology and signalling is becoming more and more recognized. However, their contribution in neuronal FA signalling and control of energy homeostasis remains unknown. Thus, this research program will provide important insights on the fundamental role of ATGL and signalling via the PEDF-ATGL pathway in hypothalamic neurons and its function in the neuronal regulation of energy homeostasis. By combining molecular and cellular aspects as well as integrative models to study metabolic physiology and neuronal circuitry in mice, our program will provide high level, multidisciplinary training of HQP.