Jin Wei, Xu Wei, Chen Jing, Zhang Xiaoxiao, Shi Lei, Ren Chuancheng
Department of Neurology, Shanghai No. 5 Hospital, Fudan University, No. 801 Heqing Road, Shanghai, 200240, China.
J Mol Histol. 2016 Jun;47(3):259-71. doi: 10.1007/s10735-016-9670-7. Epub 2016 Mar 16.
Adenosine kinase (ADK) plays a pivotal role in regulating brain function by regulating adenosine level, and ADK inhibition protects against neuronal damage in cerebral ischemia and epilepsy; however, the effects of ADK in traumatic brain injury (TBI) have not been investigated. For exploring its effects, we generated a blade-induced rat focal brain injury model. Western blot analysis, immunohistochemistry and immunofluorescent staining suggested that ADK was up-regulated after TBI, and it was temporally and spatially associated with astrogliosis. Terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling showed that neuronal apoptosis was paralleled with TBI-induced ADK up-regulation and astrogliosis. For further investigating the role of ADK in astrogliosis-induced neuronal death, primary cultured astrocytes and neurons were utilized, lipopolysaccharide (LPS) was employed to mediate astrogliosis, and condition medium (CM) of reactive astrocytes was used to treat neurons. The results showed that astrocytes increased iNOS expression and secreted pro-inflammatory cytokines after LPS treatment, and CM of reactive astrocytes resulted neuronal death. Additionally, ADK knock-down didn't ameliorate LPS-induced astrocyte proliferation, but it protected against neuronal death by reducing iNOS expression, tumor necrosis factor α and interleukin 1β secretion of reactive astrocytes. Taken together, ADK was associated with astrogliosis after TBI, its inhibition in reactive astrocytes ameliorated astrogliosis-induced neuronal death. Our findings extended the current knowledge on the role of ADK in astrogliosis, and also provided new evidence for the TBI treatment.
腺苷激酶（ADK）通过调节腺苷水平在调节脑功能中起关键作用，抑制ADK可保护脑缺血和癫痫中的神经元免受损伤；然而，ADK在创伤性脑损伤（TBI）中的作用尚未得到研究。为了探究其作用，我们建立了刀片诱导的大鼠局灶性脑损伤模型。蛋白质免疫印迹分析、免疫组织化学和免疫荧光染色表明，TBI后ADK上调，且在时间和空间上与星形胶质细胞增生相关。末端脱氧核苷酸转移酶介导的生物素化-dUTP缺口末端标记显示，神经元凋亡与TBI诱导的ADK上调和星形胶质细胞增生平行。为了进一步研究ADK在星形胶质细胞增生诱导的神经元死亡中的作用，我们使用了原代培养的星形胶质细胞和神经元，用脂多糖（LPS）介导星形胶质细胞增生，并用反应性星形胶质细胞的条件培养基（CM）处理神经元。结果表明，LPS处理后星形胶质细胞增加了诱导型一氧化氮合酶（iNOS）的表达并分泌促炎细胞因子，反应性星形胶质细胞的CM导致神经元死亡。此外，敲低ADK并不能改善LPS诱导的星形胶质细胞增殖，但通过降低反应性星形胶质细胞的iNOS表达、肿瘤坏死因子α和白细胞介素1β的分泌来保护神经元免于死亡。综上所述，ADK与TBI后的星形胶质细胞增生相关，抑制其在反应性星形胶质细胞中的表达可改善星形胶质细胞增生诱导的神经元死亡。我们的研究结果扩展了目前关于ADK在星形胶质细胞增生中作用的认识，也为TBI治疗提供了新的证据。
