JSI-124诱导急性期神经元自噬对SAH后认知功能的保护作用及其机制研究

Patients suffering from subarachnoid hemorrhage (SAH) are poor prognosis, and cognitive deficiency generally ensues. This cognitive disorder due to the apoptosis and necrosis of hippocampal neuron, which result from the hypoxic-ischemia microenvironment. Recent studies have discovered that autophagy might play a pro-survival role in the mechanism of neuron damage after SAH. In our previous research, the application of JSI-124, a drug of natural extraction, significantly induced neuronal autophagy in the rat model of SAH, in which way the cognitive deficiency was avoided. However, as a “double-edged sword”, autophagy could lead to excessive cell death caused by overdose of pro-autophagy drugs, thus exacerbating the cognitive functions following SAH. Our research intend to explore the autophagy-related phenomena based on monitoring LC3B expression in cerebrospinal fluid after SAH of rat model and discuss the fluctuations of cognitive functions via tests of neuroethology. The proper occasion, dosage and course of JSI-124 intervening in SAH are then to be established through the experiments as well as the determination of the role of JAK2/STAT3 and AMPK/mTOR pathways in the hippocampal neuronal autophagy. Results would favor the hypothesis we presented that “appropriate and moderate regulation of autophagy” could positively improve cognitive function after SAH, which would reveal high academic value and provide new clinical strategy for SAH treatment.

自发性蛛网膜下腔出血（SAH）患者常伴有认知障碍，其原因是SAH急性期全脑缺血缺氧状态引发的海马神经元凋亡及坏死。研究表明，SAH后神经元会启动自噬性保护机制以抵御神经元损伤。我们前期研究发现，在SAH模型大鼠急性期应用JSI-124可促进海马神经元自噬，预防认知障碍发生。但自噬是一把双刃剑，过度应用促自噬药物会造成大量神经元的自噬性死亡，加重SAH后的认知障碍。为此，本研究拟依据SAH大鼠脑脊液中LC3B反映的自噬水平，深入探讨SAH后海马神经元自噬的变化规律，应用认知功能检测实验确定SAH模型大鼠认知障碍的程度，找出JSI-124干预自噬的最佳时机和用药剂量与疗程，以验证我们提出的“适时与适度”上调自噬改善SAH后认知功能的假说；并阐明JAK2/STAT3和AMPK/mTOR通路在JSI-124促进海马神经元自噬中的作用。该研究有助于改善SAH患者认知功能，具有重要的学术和临床价值。

自发性蛛网膜下腔出血（SAH）患者常伴有认知障碍，其原因是SAH急性期全脑缺血缺氧状态引发的海马神经元凋亡及坏死。研究表明，SAH后神经元会启动自噬性保护机制以抵御神经元损伤。我们前期研究发现，在SAH模型大鼠急性期应用JSI-124可促进海马神经元自噬，预防认知障碍发生。经过课题组的不断摸索和实验，发现我们原标书假说中提出的适度自噬和过度自噬概念，实际为自噬和坏死性凋亡。由原定计划应用JSI-124促进自噬，改为通过坏死性凋亡抑制剂Necrostatin-1（nec-1）进行相应阻断，并保留保护性自噬的部分，使得课题思路得以清晰呈现。我们课题组发现，在SAH发生后，坏死性凋亡存在于大鼠海马组织中，并且这一过程能够被特异性抑制剂nec-1所抑制。此外，在SAH发生后，CREB-BDNF通路相关蛋白表达减少，nec-1的应用可以提高通路相关蛋白的表达，从而发挥脑保护作用。. 课题组还在研究过程中发现的一些现象，进行了多方向探索和拓展性研究。课题组以早期脑损伤（EBI）为中心，深入探讨EBI涉及的病理生理现象及相关机制，以寻求适当的干预措施来减轻EBI，从而改善SAH患者的长期预后。发现SAH发生后，CBS的表达和生物活性明显降低，给予底物L-Cysteine促进内源性H2S水平的提高，减轻EBI引发的神经元和突触损伤，从而验证了CBS在CNS中对于H2S产生的关键调控作用的同时明确了L-Cysteine在SAH中的神经保护作用是通过经CBS作用产生内源性H2S而实现；同时课题组发现嘌呤衍生物PUR可能主要通过特异性激活Shh信号通路和ERK通路,发挥对SAH后EBI的神经保护作用。. 另外，课题组不断更新和学习最新的研究进展，紧追当前研究热点，在间充质干细胞外泌体领域进行了拓展性研究。发现间充质干细胞外泌体可以通过mir-21抑制神经元凋亡来减轻SAH后的早期脑损伤。认为间充质干细胞外泌体可能是促进SAH患者康复，改善其认知障碍，提高生活质量的潜在治疗手段。