Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China.
Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China.
Biochem Biophys Res Commun. 2018 May 5;499(2):112-119. doi: 10.1016/j.bbrc.2018.02.150. Epub 2018 Feb 19.
Traumatic brain injury (TBI) is a leading cause of disability and mortality in young adults worldwide. The pathophysiology is not fully understood. Programmed necrosis (necroptosis) is a newly identified mechanism of cell death combining features of both apoptosis and necrosis. Receptor-interacting protein 3 (RIP3) plays an important role in programmed necrosis. However, the effect of RIP3-related pathway in TBI is little to be known. We attempted to explore the significance of RIP3 in regulating TBI in vivo. Significantly, TBI induced over-expression of RIP3 in the hippocampus of mice, as well as RIP1 and phosphorylated mixed lineage kinase domain-like protein (MLKL). Mice after TBI exhibited cognitive dysfunction and activation of glia cells, which were significantly attenuated by RIP3-knockout (KO). Moreover, inflammation and oxidative stress in hippocampus were markedly induced by TBI in wild type (WT) mice. Of note, the reduction of pro-inflammatory cytokines and oxidants was observed in RIP3-deficient mice, which was linked to the blockage of NLR pyrin domain containing 3 (NLRP3)/apoptosis-associated speck-like protein containing a CARD (ASC)/Caspase-1 and kelch-like ECH-associated protein 1 (Keap 1) pathways. Further, TBI induced hippocampus apoptosis, evidenced by the increase of cleaved Caspase-8/-3 and poly (ADP)-ribose polymerase (PARP) in WT mice, whereas being decreased by RIP3-knockout. In addition, RIP3 knockout led to phosphorylation of AMP-activated protein kinase α (AMPKα) in hippocampus of mice after TBI. And of note, the in vitro findings indicated that RIP3-ablation attenuated oxidative stress, inflammation and apoptosis in astrocytes, which was dependent on AMPKα activation. Together, suppressing RIP3 might be served as a therapeutic target against brain injury through inhibiting inflammation, oxidative stress and apoptosis.
创伤性脑损伤(TBI)是全球年轻人残疾和死亡的主要原因。其病理生理学尚未完全阐明。程序性细胞坏死(坏死)是一种新发现的细胞死亡机制,结合了凋亡和坏死的特征。受体相互作用蛋白 3(RIP3)在程序性坏死中起重要作用。然而,RIP3 相关途径在 TBI 中的作用知之甚少。我们试图探讨 RIP3 在体内调节 TBI 中的意义。重要的是,TBI 诱导小鼠海马中 RIP3 的过度表达,以及 RIP1 和磷酸化混合谱系激酶结构域样蛋白(MLKL)。TBI 后,小鼠表现出认知功能障碍和神经胶质细胞激活,这些症状在 RIP3 敲除(KO)小鼠中明显减轻。此外,WT 小鼠海马中明显诱导了 TBI 后的炎症和氧化应激。值得注意的是,在 RIP3 缺陷型小鼠中观察到促炎细胞因子和氧化剂减少,这与 NLR 包含 pyrin 域 3(NLRP3)/凋亡相关斑点样蛋白包含一个 CARD(ASC)/半胱氨酸天冬氨酸蛋白酶-1 和 kelch 样 ECH 相关蛋白 1(Keap1)途径的阻断有关。此外,TBI 诱导海马细胞凋亡,WT 小鼠中 cleaved Caspase-8/-3 和多聚(ADP-核糖)聚合酶(PARP)的增加证实了这一点,而 RIP3 敲除则减少了这种情况。此外,RIP3 敲除导致 TBI 后小鼠海马中的 AMP 激活蛋白激酶 α(AMPKα)磷酸化。值得注意的是,体外研究结果表明,RIP3 缺失可通过激活 AMPKα减轻星形胶质细胞中的氧化应激、炎症和凋亡。总之,抑制 RIP3 可能通过抑制炎症、氧化应激和凋亡成为治疗脑损伤的靶点。