Nampt对脑卒中后神经再生的调控及机制

Stroke is the second most common cause of death and the major cause of disability. The treatment of stroke at both acute and restoration stages remains unresolved. It is thus imperative to establish superior pharmacological strategies targeting both neural survival and regeneration. Our previous studies have identified nicotinamide phosphoribosyltransferase (Nampt) as a defense protein which is up-regulated in acute phase after cerebral ischemia; Nampt promotes neuronal survival through activating early autophagy as well as reducing apoptosis and necrosis. Most recently, by creating two strains of transgenic mice overexpressing Nampt and H247A mutant-inactivated Nampt, our preliminary experiments have demonstrated the role of Nampt in promoting neural repair following stroke, evidenced by enhancement of neuronal regeneration in the dentate gyrus of the hippocampus and of functional recovery in learning and memory. This proposal is to examine neuronal regeneration in multiple brain areas and the corresponding functional recovery in these transgenic mice after ischemic stroke, to explore the underlying metabolic signaling pathways in neural stem cell cultures under oxygen and glucose deprivation, and to test small-molecule compounds in mouse and monkey stroke models. We try to delineate a novel function of Nampt in neurogenesis following stroke, and to show the superiority of Nampt as an anti-stroke target in promoting neuronal survival, regeneration and functional recovery. The long-term goal is to identify novel therapeutic target(s) and effective small-molecule(s) in stroke model of monkeys that possess higher-order brains similar to humans.

脑卒中是第二大致死原因和主要致残原因，急救和防残均迫切需要解决，为此，寻找兼备抗神经死亡和促神经再生的靶分子至关重要。我们前期发现，烟酰胺磷酸核糖转移酶(Nampt)是一个重要的防御蛋白，在脑缺血急性期上调，通过激活早期细胞自噬、对抗细胞凋亡/坏死，发挥抗脑卒中作用。最近，我们采用首次创建的Nampt及其酶失活突变体两株转基因小鼠，预实验发现，Nampt可促进脑卒中后海马齿状回神经再生和学习记忆功能。本项目将检测多个脑区的神经再生及功能恢复；接着，在神经干细胞缺氧缺糖模型，研究代谢性信号转导通路；然后，利用小鼠和猴子脑卒中模型，测试小分子化合物的干预效应。从而，阐明Nampt酶活性在神经干细胞及神经再生中的新功能及分子机制，显示Nampt作为脑卒中防治新靶点的优越性(兼备抗神经死亡和促神经再生)。最终目标，发现在灵长类水平上有效的抗脑卒中新靶点及小分子物质，为转化研究奠定重要基础。

烟酰胺磷酸核糖转移酶(Nampt)是NAD生物合成的限速酶，一个重要的防御蛋白。我们前期研究首次证明，在脑缺血急性期，Nampt可通过激活早期细胞自噬和对抗细胞凋亡/坏死，发挥抗脑卒中作用。本项目证明细胞外Nampt(又名Visfatin或PBEF)也可通过酶活性生化通路，对抗脑缺血损伤；发现beta-arrestin-1在自噬抗脑缺血损伤过程中发挥重要作用；进一步，利用自主构建的Nampt Tg和Nampt-DN Tg两株转基因小鼠，阐明Nampt在脑缺血慢性期，可通过促进血管新生、增强神经再生，改善脑卒中后功能恢复；同时，揭示Nampt-SIRT1-Notch内皮祖细胞促血管新生信号通路，以及Nampt-SIRT1/2/6神经干细胞增殖分化促神经再生信号通路。由此证明，Nampt可作为脑卒中急救和康复的治疗靶点。在小分子化合物研究中，发现Nampt直接酶产物NMN及NMN的一个前体物质NR具有抗脑卒中活性；同时，通过5.5万个化合物高通量筛选，确认了结构多样的新型Nampt抑制剂，发现了首个Nampt荧光探针化合物，测试到一个潜在的Nampt激活剂A20具有抗脑卒中活性。进一步，利用多能干细胞创建了人源化脑缺血神经细胞模型和类脑器官模型，发现了在灵长类水平上有效的抗脑卒中物质NMN和A20，其中NMN已作为脑缺血治疗新药进入临床前研究。 . 在Trends Pharmacol Sci、Prog Neurobiol、Autophagy、Stroke、Cardiovasc Res、Br J Pharmacol等发表SCI论文24篇，其中影响因子5以上12篇、10以上3篇；主编专著1部；特邀报告21次；授权专利6项；国际指南1项；临床前新药1项；培养国家优青1名，863青年科学家1名，研究生毕业12名；举办国际国内会议3次；获上海市自然科学二等奖、全国优秀科技工作者，当选中国药理学会心血管药理主任委员。