Melatonin protects against ischemic stroke by modulating microglia/macrophage polarization toward anti-inflammatory phenotype through STAT3 pathway
Melatonin protects against ischemic stroke by modulating microglia/macrophage polarization toward anti-inflammatory phenotype through STAT3 pathway
复制标题
褪黑激素通过 STAT3 通路调节小胶质细胞/巨噬细胞极化至抗炎表型，从而预防缺血性中风
DOI：
10.1111/cns.13261
复制
发表时间：
2019-12-01
影响因子：
5.5
通讯作者：
Xi, Jia-Ning
中科院分区：
文献类型：
--
作者：
Liu, Zong-Jian;Ran, Yuan-Yuan;Xi, Jia-Ning
目的小胶质细胞和浸润的巨噬细胞在缺血性脑卒中后的炎症过程中起重要作用。调节小胶质细胞/巨噬细胞从促炎表型到抗炎状态的极化已被认为是治疗缺血性卒中的潜在治疗方法。褪黑激素在实验性中风模型中显示出神经保护作用。然而，褪黑激素对脑卒中后小胶质细胞极化的影响及其机制尚不清楚。方法采用C57 BL/6 J小鼠大脑中动脉远端闭塞（dMCAO）法制备脑缺血模型。在缺血后0和24小时腹腔注射褪黑激素（20 mg/kg）。在体外，用从氧-葡萄糖剥夺（OGD）攻击的神经元细胞系Neuro-2a（N2 a）收集的条件培养基（CM）刺激小胶质细胞系BV 2至促炎状态。实时荧光定量PCR检测小胶质细胞表型标志物mRNA的表达。通过磷酸化的STAT 3（pSTAT 3）的Western印迹确定信号转导和转录激活子3（STAT 3）途径的激活。使用神经元-小胶质细胞共培养系统来确定褪黑激素是否可以抑制促炎性小胶质细胞对OGD后神经元的神经毒性作用。结果褪黑激素治疗可减少脑梗死面积，改善神经功能，并伴有促炎性标志物表达减少和抗炎性标志物表达增加。体外研究证实，褪黑激素直接抑制暴露于OGD神经元CM后BV 2细胞中的促炎反应。具有促炎表型的小胶质细胞加剧了OGD后N2 a细胞的死亡，而褪黑激素降低了这种神经毒性作用。此外，褪黑激素增强了OGD神经元CM处理的BV 2细胞中pSTAT 3表达的抑制。STAT 3阻断显著降低褪黑激素对小胶质细胞表型转变的影响。结论：褪黑激素治疗至少部分地通过以STAT 3依赖性方式将小胶质细胞表型从促炎极性转变为抗炎极性来改善脑损伤。
Aims Microglia and infiltrated macrophages play important roles in inflammatory processes after ischemic stroke. Modulating microglia/macrophage polarization from pro-inflammatory phenotype to anti-inflammatory state has been suggested as a potential therapeutic approach in the treatment of ischemic stroke. Melatonin has been shown to be neuroprotective in experimental stroke models. However, the effect of melatonin on microglia polarization after stroke and underlying mechanisms remain unknown. Methods In vivo, cerebral ischemia was induced by distal middle cerebral artery occlusion (dMCAO) in C57BL/6J mice. Melatonin was injected intraperitoneally (20 mg/kg) at 0 and 24 hours after ischemia. In vitro, the microglial cell line BV2 was stimulated to the pro-inflammatory state with conditioned media (CM) collected from oxygen-glucose deprivation (OGD) challenged neuronal cell line Neuro-2a (N2a). Real-time PCR was utilized to detect the mRNA expression of microglia phenotype markers. Activation of signal transducer and activator of transcription 3 (STAT3) pathway was determined by Western blot of phosphorylated STAT3 (pSTAT3). A neuron-microglia co-culture system was used to determine whether melatonin can inhibit the neurotoxic effect of pro-inflammatory microglia to post-OGD neurons. Results Melatonin treatment reduced brain infarct and improved neurological functions 3 days after dMCAO, which was accompanied by decreased expression of pro-inflammatory markers and increased expression of anti-inflammatory markers in the ischemic brain. In vitro studies confirmed that melatonin directly inhibited the pro-inflammatory responses in BV2 cells upon exposure to OGD neuron CM. The microglia possessing pro-inflammatory phenotype exacerbated post-OGD N2a cells death, whereas melatonin reduced such neurotoxic effect. Further, melatonin enhanced the otherwise inhibited pSTAT3 expression in BV2 cells treated with OGD neuron CM. STAT3 blockade significantly reduced the effect of melatonin on microglial phenotype shift. Conclusion: Melatonin treatment ameliorates brain damage at least partially through shifting microglia phenotype from pro-inflammatory to anti-inflammatory polarity in a STAT3-dependent manner.