CPT1A在缺血性脑卒中反应性星形胶质细胞脂肪酸代谢障碍中的作用、机制及CPT1A激活药物的发现

星形胶质细胞线粒体β氧化消耗脂滴中脂肪酸支持神经元活动。已发现局灶性脑卒中诱导星形胶质细胞脂滴增加。但脂滴增加原因及促星形胶质细胞增生机制未知。预实验发现星形胶质细胞线粒体β氧化关键调节酶CPT1A及代谢产物L-Palmitoylcarnitine下调；CPT1A抑制剂加重脑缺血诱导溶酶体脂滴堆积，溶酶体膜Hsp70转到脂滴，溶酶体膜损伤，促星形胶质细胞增生，加重脑损伤。本项目在体内、外脑缺血诱导胶质瘢痕模型研究：CPT1A失能介导脂肪酸代谢障碍促星形胶质细胞增生，加重脑损伤；CPT1A下调致溶酶体脂滴堆积，损伤溶酶体膜的分子机制及溶酶体介导促星形胶质细胞增生机制；神经元脂滴向星形胶质细胞转移；分子模拟虚拟筛选CPT1A激动剂及其药理活性研究。以发现调控反应性星形胶质细胞的内源性新靶点CPT1A及其激活剂。

Astrocytes consume fatty acids in lipid droplets through mitochondrial β oxidation, which plays a key role in neuronal activity and brain health. The literature found that focal ischemic stroke induced increase in lipid droplets of reactive astrocytes. However, the cause of the increase in lipid droplets and the mechanisms of lipid droplets-mediated astrogliosis are still unknown. Our preliminary experimental results showed that: CPT1A (carnitine O-palmitoyltransferase 1), a key regulator of mitochondrial fatty acid β oxidation, was down-regulated in astrocytes, simultaneously its metabolite L-Palmitoylcarnitine was also reduced; CPT1A specific inhibitor aggravated ischemic stroke-induced lipid droplet accumulation in lysosomes, resulting in that Hsp70 transfers to the lipid droplet from the lysosomal membranes, the lysosomal membranes damage and activating lysosome-mediated signaling pathways of astrogliosis and glial scar formation, as well as deteriorating ischemic stroke-induced brain injury. .Using the glial scar formation models induced by middle cerebral artery occlusion/reperfusion in vivo and primary culture astrocytes and human astrocytes exposed to oxygen-glucose deprivation/ rexygenation (OGD/Re) injury in vitro, this project is planning to investigate: the dysfunction of mitochondrial CPT1A- mediated disorder in fatty acid metabolism of astrocytes promotes astrogliosis and glial scar formation and contributes to ischemic stroke-induced brain injury; the role of CPT1A dysfunction-mediated excessive accumulation of lipid droplets in its autophagy / lysosomal degradation pathway and the molecular mechanism of lysosomal membrane damage that the Hsp70 on lysosomal membrane transfers to the lipid droplets, and the mechanism that the activation of lysosomal cathepsin B-TGF-β-smads pathway in promotes astrogliosis and glial scar formation; the effect of astrocytes CPT1A dysfunction on the transfer of neuronal lipid droplets to astrocytes; molecular structure modeling of human CPT1A and virtual screening of CPT1A activators and the identification of their pharmacology activities. This project will provide the new endogenous target of CPT1A in regulating reactive astrogliosis and glial scar formation, and its activators for ischemic stroke therapy.