Intranasal administration of recombinant Netrin-1 attenuates neuronal apoptosis by activating DCC/APPL-1/AKT signaling pathway after subarachnoid hemorrhage in rats.
Intranasal administration of recombinant Netrin-1 attenuates neuronal apoptosis by activating DCC/APPL-1/AKT signaling pathway after subarachnoid hemorrhage in rats.
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DOI：
10.1016/j.neuropharm.2017.03.025
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发表时间：
2017-06
影响因子：
4.7
通讯作者：
Zhang JH
中科院分区：
文献类型：
--
作者：
Xie Z;Huang L;Enkhjargal B;Reis C;Wan W;Tang J;Cheng Y;Zhang JH
神经元凋亡是蛛网膜下腔出血（SAH）后早期脑损伤的关键病理过程。目前仍缺乏改善神经元凋亡的有效治疗策略。我们旨在确定鼻内给予外源性轴突导向因子-1（NTN - 1）是否能够减轻实验性SAH后的神经元凋亡，特别是通过激活依赖于结直肠癌缺失基因（DCC）的衔接蛋白-1（APPL - 1）/蛋白激酶B（AKT）信号级联。225只雄性Sprague - Dawley大鼠采用血管内穿刺法制备SAH模型。重组人NTN - 1（rNTN - 1）经鼻内给药。NTN - 1小干扰RNA（siRNA）、APPL - 1 siRNA和AKT抑制剂MK2206通过脑室内（i.c.v.）注射给药。检测SAH分级、神经功能评分、通过裂解的半胱天冬酶-3（CC - 3）表达和荧光玉红C（FJC）染色评估的神经元凋亡、双重免疫荧光染色以及蛋白质印迹分析。我们的结果显示，SAH后内源性NTN - 1水平升高。给予rNTN - 1可改善SAH后24小时和72小时的神经功能预后，而内源性NTN - 1的敲低则加重神经功能损伤。此外，外源性rNTN - 1治疗促进了APPL - 1的活化，增加了磷酸化 - AKT和Bcl - 2的表达，同时降低了凋亡标志物CC - 3的表达以及FJC阳性神经元的数量，从而减轻了神经元凋亡。相反，APPL - 1 siRNA和MK2206消除了SAH后24小时外源性rNTN - 1的抗凋亡作用。总之，鼻内给予外源性rNTN - 1可减轻SAH大鼠的神经元凋亡并改善其神经功能，至少部分是通过激活DCC/APPL - 1/AKT信号通路实现的。
Neuronal apoptosis is a crucial pathological process in early brain injury after subarachnoid hemorrhage (SAH). The effective therapeutic strategies to ameliorate neuronal apoptosis are still absent. We intended to determine whether intranasal administration of exogenous Netrin-1 (NTN-1) could attenuate neuronal apoptosis after experimental SAH, specifically via activating DCC-dependent APPL-1/AKT signaling cascade. Two hundred twenty-five male Sprague-Dawley rats were subjected to the endovascular perforation model of SAH. Recombinant human NTN-1 (rNTN-1) was administered intranasally. NTN-1 small interfering RNA (siRNA), APPL-1 siRNA, and AKT inhibitor MK2206 were administered through intracerebroventricular (i.c.v.) injection. SAH grade, neurological score, neuronal apoptosis assessed by cleaved caspase-3 (CC-3) expression and Fluoro-Jade C (FJC) staining, double immunofluorescence staining, and Western blot were examined. Our results revealed that endogenous NTN-1 level was increased after SAH. Administration of rNTN-1 improved neurological outcomes at 24 h and 72 h after SAH, while knockdown of endogenous NTN-1 worsened neurological impairments. Furthermore, exogenous rNTN-1 treatment promoted APPL-1 activation, increased phosphorylated-AKT and Bcl-2 expression, as well as decreased apoptotic marker CC-3 expression and the number of FJC-positive neurons, thereby alleviated neuronal apoptosis. Conversely, APPL-1 siRNA and MK2206 abolished the anti-apoptotic effect of exogenous rNTN-1 at 24 h after SAH. Collectively, intranasal administration of exogenous rNTN-1 attenuated neuronal apoptosis and improved neurological function in SAH rats, at least in apart via activating DCC/APPL-1/AKT signaling pathway.