神经元自噬调控NLRP1炎性小体在蛛网膜下腔出血后早期脑损伤中的机制研究

Subarachnoid hemorrhage(SAH) is a devastating disease with high mortality and significant morbidity among patients. Early brain injury following SAH is considered as the primary cause of poor outcome after SAH and remains no effective therapy. Autophagy is a homeostatic process that involves the sequestration of cytoplasmic components in double-membraned autophagosomes. Autophagy acts as a survival mechanism under conditions of stress, maintaining cellular integrity by regenerating metabolic precursors and clearing subcellular debris. Our previous study have demonstrated that autophagy activation is associated with neuroprotection against apoptosis in a rat model of SAH. However, the exact molecular mechanism of that still remains obscure. Inflammasomes are essentail protein complexes which have been implacated in a arrange of neurological diseases, but whether and how inflammasomes are involved in the process of autophagy after SAH remains unknown. Our preliminary inspections showed that NLRP1 inflammasome was significantly regulated by autophagy in SAH rat model, and blocking NLRP1 could significantly attenuate the neuroprotection provided by autophagy. This study was undertaken to investigate the role and the mechanisms of autophagy-NLRP1 pathway in early brain injury following SAH in both animal and cellular levels, and thus to provide a new target for SAH treatment.

蛛网膜下腔出血（SAH）是一种严重危害健康的疾病，它引发的早期脑损伤是其首要的致病机制，但目前仍缺乏有效的干预手段。自噬是细胞内溶酶体依赖的物质降解过程，它对维持细胞自稳态、应对内外环境刺激具有重要意义。我们前期研究发现，自噬激活对SAH后早期脑损伤发挥着显著的神经保护作用，但其具体作用机制尚不明确。炎性小体介导的炎性反应广泛参与众多神经系统疾病的发生发展，但尚未有报道其与SAH后神经元自噬间的联系。我们最新研究发现，SAH后神经元自噬可显著调控NLRP1炎性小体活性水平，阻断NLRP1将显著削弱自噬的神经保护作用。因此我们将围绕神经元自噬-NLRP1炎性小体通路，利用SAH模型大鼠、原代神经元细胞及成熟的神经元细胞系，采用免疫印迹、RNA干扰、CRISPR/CAS9等技术，从体内、体外两个层面，阐明神经元自噬缓解SAH后早期脑损伤的具体作用机制，为临床治疗SAH提供新思路和理论依据。

目前蛛网膜下腔出血后早期脑损伤的病理生理学机制已经有了初步的认识，如颅内压升高、脑灌注压下降、脑血流量降低、氧合缺乏、血脑屏障破坏及神经元的死亡。其中自噬/线粒体自噬具有维持细胞自我稳态、促进细胞生存但也有促进细胞死亡的作用，其在蛛网膜下腔出血后早期脑损伤中作用的机制和效应是本研究领域的热点和潜在的治疗靶点。因此，本研究旨在阐明自噬/线粒体在蛛网膜下腔出血后早期脑损伤中的作用及与NLRP3炎症小体的关系并寻找行之有效的治疗性药物。在本研究中，我们分别应用自噬/线粒体自噬的诱导剂及抑制剂来调控自噬/线粒体自噬的水平，监测不同的自噬激活状态下早期脑损伤的程度；进一步地我们检测NLRP3炎症小体相关蛋白来探讨自噬与炎症小体间的关系；最后我们发现氟西汀及褪黑素能够通过自噬/线粒体自噬来调控NLRP3炎症小体的生成与活化。我们研究得出以下结论：蛛网膜下腔出血后急性期自噬通路被激活，自噬/线粒体自噬是通过减少NLRP3炎症小体来发挥神经保护；氟西汀和褪黑素通过激活自噬/线粒体自噬的作用调控NLRP3炎症小体。本研究为蛛网膜下腔出血的治疗提供新策略和新靶点，为临床转化提供可能。