Chloride homeostasis in neuronal compartments under acute metabolic stress

在神经元中，横跨质膜和细胞膜的氯离子梯度具有多种细胞功能，如调节兴奋性、神经递质释放、pH和体积调节。氯离子浓度是通过各种离子通道和次级活性转运体的相互作用来确定的，这些转运体将阴离子浓度与Na+、K+和H+的电化学梯度偶联。因此，代谢应激过程中[Na+]、[K+]和[H+]的变化有望改变细胞内[Cl-]。我们将研究在正常条件下和代谢应激下神经元体细胞和神经元延伸以及胞内细胞器中的氯离子稳态。我们将使用荧光寿命成像显微镜与喹啉基荧光指示器或荧光成像与基因编码氯传感器以及阴离子选择通道的反转电位的电生理分析。Cl-离子在调节谷氨酸在谷氨酸能神经元突触囊泡中的积累中起着重要作用，我们将研究谷氨酸和氯离子浓度如何相互修饰。Cl-/H+交换器连接内体中的[Cl-]和pH，我们将分析在正常条件下以及在能量限制下这些细胞器中的pH调节和氯离子稳态是如何相互交织的。

In neurons, chloride gradients across the plasma membrane as well as across intracellular membranes serve multiple cellular functions, such as regulation of excitability, neurotransmitter release and pH and volume regulation. Chloride concentrations are determined via the interplay of various ion channels and secondary active transporters that couple anion concentrations to the electrochemical gradients of Na+, K+ and H+. Changes in [Na+], [K+] and [H+] during metabolic stress are thus expected to alter intracellular [Cl-]. We will study the chloride homeostasis in the neuronal soma and in neuronal extensions as well as in intracellular organelles under normal conditions and under metabolic stress. We will use fluorescence lifetime imaging microscopy with quinolinium-based fluorescent indicators or fluorescence imaging with genetically encoded chloride sensors as well as the electrophysiological analysis of reversal potentials of anion-selective channels. Cl- ions play an important role in regulating glutamate accumulation in synaptic vesicles of glutamatergic neurons, and we will study how glutamate and chloride concentrations modify each other. Cl-/H+ exchangers link [Cl-] and pH in endosomes, and we will analyze how pH regulation and chloride homeostasis are intertwined in these organelles under normal conditions as well as under energy restriction.