The Affiliated Hospital of Xizang Minzu University, Xianyang City, Shaanxi, China.
The Affiliated Hospital of Xizang Minzu University, Xianyang City, Shaanxi, China.
J Stroke Cerebrovasc Dis. 2020 Jan;29(1):104485. doi: 10.1016/j.jstrokecerebrovasdis.2019.104485. Epub 2019 Nov 6.
Tenascin-C (TNC) is upregulated in serum and cerebrospinal fluid after subarachnoid hemorrhage (SAH) and the deficiency of TNC could alleviate neuronal apoptosis and neuroinflammation after SAH. However, the specific mechanism of TNC regulating neuronal apoptosis and neuroinflammation after SAH is not well recognized. The aim of this study was to investigate whether PI3K/Akt/ NF-κB signaling pathway is involved in the regulation of TNC on early brain injury after SAH.
Oxygen hemoglobin (OxyHb) was used to induce SAH models in PC12 cells, and classified into control, SAH, LY294002, SAH+TNC-siRNA and SAH+TNC-siRNA+LY groups. Western blotting was applied to examine the protein expression of TNC, Caspase-3, Bax, Bcl-2, PI3K, p-Akt, and p-NF-κB. Reverse transcription quantitative polymerase chain reaction was applied to examine the TNC mRNA expression. Cholecystokinin (CCK)-8 and flow cytometry were used to examine cell proliferation and apoptosis, respectively. ELISA was applied to examine the content of interleukin 6, interleukin 1β, and tumor necrosis factor α. We showed that the TNC protein was highly expressed in SAH cell model.
OxyHb inhibited cell proliferation, promoted cell apoptosis and the expression of proapoptotic protein, and promoted proinflammatory cytokine secretion in PC12 cells, which were restored following TNC gene silencing. Moreover, OxyHb decreased the expression of PI3K and p-Akt and increased the expression of p-NF-κB p65 in PC12 cells, which were activated following TNC gene silencing. The LY294002 weakened the effect of TNC gene silencing.
The TNC gene silencing relieved neuronal apoptosis and neuroinflammation by activating the PI3K/Akt/ NF-κB signaling pathway. TNC-induced neuroinflammation would be a new target to improve outcome after SAH.
蛛网膜下腔出血（SAH）后，Tenascin-C（TNC）在血清和脑脊液中上调，TNC 的缺乏可减轻 SAH 后神经元凋亡和神经炎症。然而，TNC 调节 SAH 后神经元凋亡和神经炎症的确切机制尚不清楚。本研究旨在探讨 PI3K/Akt/NF-κB 信号通路是否参与 TNC 对 SAH 后早期脑损伤的调节。
用氧合血红蛋白（OxyHb）诱导 PC12 细胞 SAH 模型，分为对照组、SAH 组、LY294002 组、SAH+TNC-siRNA 组和 SAH+TNC-siRNA+LY 组。采用 Western blot 法检测 TNC、Caspase-3、Bax、Bcl-2、PI3K、p-Akt 和 p-NF-κB 蛋白表达。采用逆转录定量聚合酶链反应（qRT-PCR）检测 TNC mRNA 表达。CCK-8 法和流式细胞术分别检测细胞增殖和凋亡。ELISA 法检测白细胞介素 6（IL-6）、白细胞介素 1β（IL-1β）和肿瘤坏死因子-α（TNF-α）含量。结果显示，SAH 细胞模型中 TNC 蛋白高表达。
OxyHb 抑制 PC12 细胞增殖，促进细胞凋亡和促凋亡蛋白表达，促进 PC12 细胞分泌促炎细胞因子，TNC 基因沉默后恢复。此外，OxyHb 降低了 PC12 细胞中 PI3K 和 p-Akt 的表达，增加了 p-NF-κB p65 的表达，TNC 基因沉默后被激活。LY294002 削弱了 TNC 基因沉默的作用。
TNC 基因沉默通过激活 PI3K/Akt/NF-κB 信号通路减轻神经元凋亡和神经炎症。TNC 诱导的神经炎症可能成为改善 SAH 后结局的新靶点。
