The regulation and function of lipid metabolism in astrocytes

背景：神经元与星形胶质细胞的通讯对于大脑的功能是必不可少的。神经生物学的一个令人兴奋的领域是研究脂肪酸代谢在神经元-星形胶质细胞偶联中的作用。虽然神经元代谢脂肪酸的能力很低，但星形胶质细胞很容易代谢脂肪酸来响应神经元的活动。星形胶质细胞脂肪酸代谢增加的结果是什么？线粒体氧化脂肪酸产生三磷酸腺苷。三磷酸腺苷可以被包装成囊泡并由星形胶质细胞分泌，在那里它通过调节神经元的活动而发挥神经胶质递质的功能。这项研究计划的主要目标是研究脂肪酸代谢在大脑功能中的作用。为了实现这一目标，我们的直接目标是揭示星形胶质细胞中脂肪酸代谢增加的功能和机制，以响应神经活动。具体目标：1.星形胶质细胞如何改变脂肪酸代谢以响应神经活动？我们发现星形胶质细胞增加脂肪酸代谢是对神经元活动的反应，然而，调节这一反应的机制尚不清楚。我们将确定星形胶质细胞用来增加脂肪酸代谢的信号转导途径，以响应神经活动(谷氨酸)。2.脂肪酸代谢对ATP阳性囊泡的形成有何贡献？脂肪酸或碳水化合物的线粒体代谢产生三磷酸腺苷。星形胶质细胞产生的三磷酸腺苷可以直接在胞浆中使用，也可以装入囊泡释放。我们现在将确定脂肪酸代谢在星形胶质细胞中形成ATP阳性囊泡中的作用。3.星形胶质细胞的脂肪酸代谢如何影响ATP的释放？星形胶质细胞增加脂肪酸代谢，以响应神经活动的增加，但尚不清楚这是否会导致ATP释放增加。我们现在将确定脂肪酸代谢对囊泡ATP分泌的影响。建议方法：我们将以原代培养的星形胶质细胞作为模型系统。我们的实验将包括定量荧光显微镜[包括超分辨显微镜和活细胞全内反射(TIRF)显微镜]、Western blotting和从星形胶质细胞条件培养液中生化检测ATP。研究意义：神经元与星形胶质细胞的通讯对大脑功能是不可或缺的。然而，脂肪酸代谢在神经元和星形胶质细胞偶联中的作用尚不清楚。这项研究计划旨在揭示星形胶质细胞是如何利用脂肪酸与神经元交流并影响其活动的。最终，这个项目将揭示大脑中星形胶质细胞的功能以及它们如何支持适当的神经元功能的重要见解。

Background: Neuron-astrocyte communication is essential for the brain to function. An exciting area in neurobiology is investigating the role of fatty acid metabolism in neuron-astrocyte coupling. While neurons have a low capacity to metabolize fatty acids, astrocytes readily metabolize fatty acids in response to neuronal activity. What is the result of this increased fatty acid metabolism in astrocytes? Mitochondrial oxidation of fatty acids produces ATP. ATP can be packaged into vesicles and secreted by astrocytes where it functions as a gliotransmitter by modulating neuronal activity. The main goal of this research program is to investigate the role of fatty acid metabolism in brain function. To work towards this goal, our immediate objective is to uncover the function and mechanisms of increased fatty acid metabolism in astrocytes in response to neural activity. Specific Aims: 1.How do astrocytes alter fatty acid metabolism in response to neural activity? We discovered that astrocytes increase fatty acid metabolism in response to neuronal activity, however the mechanisms that mediate this response are unknown. We will determine the signal transduction pathways used by astrocytes to increase fatty acid metabolism in response to neural activity (glutamate). 2.What is the contribution of fatty acid metabolism to ATP-positive vesicle formation? Mitochondrial metabolism of fatty acids or carbohydrates generate ATP. ATP produced in astrocytes can be used directly in the cytosol or loaded into vesicles for release. We will now determine the contribution of fatty acid metabolism in the formation of ATP-positive vesicles in astrocytes. 3.How does fatty acid metabolism in astrocytes influence ATP release? Astrocytes increase fatty acid metabolism in response to increased neural activity but it is unclear whether this results in increased ATP release. We will now determine the effects of fatty acid metabolism on vesicular ATP secretion. Proposed Methods: We will use primary cultured astrocytes as our model system. Our experiments will involve a combination of quantitative fluorescence microscopy [including super-resolution and live-cell total internal reflection (TIRF) microscopy], Western blotting, and biochemical detection of ATP from astrocyte-conditioned medium. Significance of Research: Neuron-astrocyte communication is integral to brain function. Yet the contribution of fatty acid metabolism in coupling neuron and astrocytes is unknown. This research program aims to uncover how astrocytes utilize fatty acids in order to communicate with neurons and influence their activity. Ultimately, this program will uncover important insights into the function of astrocytes in the brain and how they support proper neuronal function.