Zhang Li, Tan Jinyun, Jiang Xiaoping, Qian Weiwei, Yang Ting, Sun Xijun, Chen Zhaohui, Zhu Qiwen
Department of Radiology, The Second People's Hospital of Lanzhou, No. 388 Jingyuan Road, Chengguan District, Lanzhou, 730046, China.
Biol Res. 2017 Sep 4;50(1):26. doi: 10.1186/s40659-017-0130-y.
CCL2 was up-regulated in neurons and involved in microglia activation and neurological decline in mice suffering from hepatic encephalopathy (HE). However, no data exist concerning the effect of neuron-derived CCL2 on microglia activation in vitro.
The rats were pretreated with CCL2 receptor inhibitors (INCB or C021, 1 mg/kg/day i.p.) for 3 days prior to thioacetamide (TAA) administration (300 mg/kg/day i.p.) for inducing HE model. At 8 h following the last injection (and every 4 h after), the grade of encephalopathy was assessed. Blood and whole brains were collected at coma for measuring CCL2 and Iba1 expression. In vitro, primary neurons were stimulated with TNF-α, and then the medium were collected for addition to microglia cultures with or without INCB or C021 pretreatment. The effect of the medium on microglia proliferation and activation was evaluated after 24 h.
CCL2 expression and microglia activation were elevated in the cerebral cortex of rats received TAA alone. CCL2 receptors inhibition improved neurological score and reduced cortical microglia activation. In vitro, TNF-α treatment induced CCL2 release by neurons. Medium from TNF-α stimulated neurons caused microglia proliferation and M1 markers expression, including iNOS, COX2, IL-6 and IL-1β, which could be suppressed by INCB or C021 pretreatment. The medium could also facilitate p65 nuclear translocation and IκBα phosphorylation, and NF-κB inhibition reduced the increased IL-6 and IL-1β expression induced by the medium.
Neuron-derived CCL2 contributed to microglia activation and neurological decline in HE. Blocking CCL2 or inhibiting microglia excessive activation may be potential strategies for HE.
在患有肝性脑病（HE）的小鼠中，神经元中CCL2上调，并参与小胶质细胞激活和神经功能衰退。然而，关于神经元源性CCL2对体外小胶质细胞激活的影响尚无数据。
在给予硫代乙酰胺（TAA，300mg/kg/天，腹腔注射）诱导HE模型前3天，大鼠用CCL2受体抑制剂（INCB或C021，1mg/kg/天，腹腔注射）预处理。在最后一次注射后8小时（之后每4小时）评估脑病分级。在昏迷时采集血液和全脑以测量CCL2和Iba1表达。在体外，用TNF-α刺激原代神经元，然后收集培养基添加到经或未经INCB或C021预处理的小胶质细胞培养物中。24小时后评估培养基对小胶质细胞增殖和激活的影响。
单独接受TAA的大鼠大脑皮质中CCL2表达和小胶质细胞激活升高。CCL2受体抑制改善神经评分并减少皮质小胶质细胞激活。在体外，TNF-α处理诱导神经元释放CCL2。来自TNF-α刺激神经元的培养基导致小胶质细胞增殖和M1标志物表达，包括iNOS、COX2、IL-6和IL-1β，这可被INCB或C021预处理抑制。该培养基还可促进p65核转位和IκBα磷酸化，并且NF-κB抑制减少了由该培养基诱导的IL-6和IL-1β表达增加。
神经元源性CCL2促成HE中的小胶质细胞激活和神经功能衰退。阻断CCL2或抑制小胶质细胞过度激活可能是HE的潜在治疗策略。
