MCT2介导神经元乳酸摄取在GPR40调节癫痫发作中的作用及机制研究

Epileptic seizures consume a large amount of energy. G protein-coupled receptor 40 (GPR40) is an important protein regulating energy metabolism. In our previous study, we have found that activation of GPR40 can inhibit excitatory synaptic transmission and epileptic seizures (Yang Yong, et al., Science Advances, 2018). But its mechanism is unclear. Monocarboxylic acid transporter 2 (MCT2) mediated lactic acid uptake is an important approach for neurons to obtain energy substrates. It was found that GPR40 could regulate the neuronal energy metabolism, and inhibition of MCT2 could block the effect of GPR40 on neuronal energy metabolism and neuronal activity. Based on this, we propose that MCT2-mediated lactic acid uptake is involved in the regulation of epileptic seizures by GPR40. This study intends to clarify the effect of GPR40 on MCT2-mediated lactic acid transport and its mechanism on the levels of molecule, cell, animal and tissues from epileptic patients, by using molecular biology, whole-cell patch clamp and animal experiments techniques. By these studies, we hope to reveal the metabolic mechanism of GPR40 regulating epileptic seizures and to provide a new theoretical basis for exploring new targets for antiepileptic therapy.

癫痫发作需要消耗大量的能量。G蛋白偶联受体40（GPR40）是调节机体能量代谢的重要蛋白。前期研究发现，激活GPR40可抑制兴奋性突触传递和减少癫痫发作（Yang Yong, et al., Science Advances，2018），但其作用机制尚不清楚。单羧酸转运体2（MCT2）介导乳酸摄取是神经元获取能量底物的重要方式；通过预实验发现，GPR40可调节神经元的MCT2表达水平和能量代谢活性，抑制MCT2可阻断GPR40对神经元能量代谢和神经元活性的作用。据此我们提出假说：MCT2介导的乳酸摄取在GPR40调节癫痫发作中起到重要作用。本课题拟在分子、细胞、动物和癫痫病人脑组织等多层面，利用分子生物学、全细胞膜片钳、动物行为学等技术，明确GPR40对MCT2介导的乳酸摄取的调节作用，并探讨其机制，从而揭示GPR40调节癫痫发作的代谢机制，为探索抗癫痫治疗的新靶点提供新的理论依据。

本课题延续前期的研究成果，继续深入研究GPR40参与癫痫的机制。首先明确了GPR40 对神经元能量代谢的作用，并证实了GPR40调节神经能量代谢依赖于MCT2。进一步研究发现GPR40通过MCT2参与调节癫痫发作，并通过研究MCT2膜蛋白表达改变和下游分子CREB探讨了GPR40调节MCT2的机制。本课题还延伸研究了GPR40对铁死亡的调节。最后，为了以后更好的深入研究GPR40，我们还构建了GPR40条件敲除小鼠。通过以上研究，在分子、细胞和动物等层面，阐释了GPR40调节癫痫发作的机制，为探索抗癫痫治疗的新靶点提供新的理论依据，为进一步的深入研究提供了更加坚实的基础和条件。