Lipocalin-2 may produce damaging effect after cerebral ischemia by inducing astrocytes classical activation
Lipocalin-2 may produce damaging effect after cerebral ischemia by inducing astrocytes classical activation
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DOI：
10.1186/s12974-019-1556-7
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发表时间：
2019-08
影响因子：
9.3
通讯作者：
Nana Zhao;Xiaomeng Xu;Yongjun Jiang;Jie Gao;F. Wang;Xiaohui Xu;Zhuoyu Wen;Yi Xie;Juanji Li;Rongrong Li;Qiushi Lv;Qian Liu;Q. Dai;Xinfeng Liu;Gelin Xu
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文献类型：
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作者：
Nana Zhao;Xiaomeng Xu;Yongjun Jiang;Jie Gao;F. Wang;Xiaohui Xu;Zhuoyu Wen;Yi Xie;Juanji Li;Rongrong Li;Qiushi Lv;Qian Liu;Q. Dai;Xinfeng Liu;Gelin Xu
背景星形胶质细胞在缺血性卒中后康复中的作用，特别是对炎症过程的影响，仍然存在争议。方法检测缺氧性脑损伤后0 h、6 h、12 h、24 h、48 h原代星形胶质细胞中炎性因子的水平，采用磁珠分选法将缺氧星形胶质细胞分为诱导型一氧化氮合酶阳性(iNOS+)和诱导型一氧化氮合酶阴性(iNOS(−))。通过检测诱导型一氧化氮合酶、胶质纤维酸性蛋白和Iba-1在大脑中动脉闭塞脑片上的共定位，进一步验证了星形胶质细胞在体内的极化。慢病毒过表达LCN2和LCN2基因敲除小鼠(#024630。研究了Lcn2在星形胶质细胞功能极化中的作用。结果缺氧缺糖后原代星形胶质细胞iNOS mRNA表达在6 h达到高峰，而Lcn2基因敲除的星形胶质细胞iNOS mRNA表达基本不变。在短暂性大脑中动脉闭塞(TMCAO)小鼠，Lcn2被证明是星形胶质细胞经典激活所必需的。在Lcn2基因敲除的MCAO小鼠中，未检测到经典激活的星形胶质细胞，且梗塞体积较小，神经功能较好。结论脑缺血后星形胶质细胞激活的新模式，而Lcn2在极化和激活星形胶质细胞中起关键作用。
BackgroundFunctions of astrocytes in the rehabilitation after ischemic stroke, especially their impacts on inflammatory processes, remain controversial. This study uncovered two phenotypes of astrocytes, of which one was helpful, and the other harmful to anoxic neurons after brain ischemia.MethodsWe tested the levels of inflammatory factors including TNF-a, IL-6, IL-10, iNOS, IL-1beta, and CXCL10 in primary astrocytes at 0 h, 6 h, 12 h, 24 h, and 48 h after OGD, grouped the hypoxia astrocytes into iNOS-positive (iNOS(+)) and iNOS-negative (iNOS(−)) by magnetic bead sorting, and then co-cultured the two groups of cells with OGD-treated neurons for 24 h. We further verified the polarization of astrocytes in vivo by detecting the co-localization of iNOS, GFAP, and Iba-1 on MCAO brain sections. Lentivirus overexpressing LCN2 and LCN2 knockout mice (#024630. JAX, USA) were used to explore the role of LCN2 in the functional polarization of astrocytes. 7.0-T MRI scanning and the modified Neurological Severity Score (mNSS) were used to evaluate the neurological outcomes of the mice.ResultsAfter oxygen-glucose deprivation (OGD), iNOS mRNA expression increased to the peak at 6 h in primary astrocytes, but keep baseline expression in LCN2-knockout astrocytes. In mice with transient middle cerebral artery occlusion (tMCAO), LCN2 was proved necessary for astrocyte classical activation. In LCN2 knockout mice with MCAO, no classically activated astrocytes were detected, and smaller infarct volumes and better neurological functions were observed.ConclusionsThe results indicated a novel pattern of astrocyte activation after ischemic stroke and lipocalin-2 (LCN2) plays a key role in polarizing and activating astrocytes.