Yang Xiaodong, Lou Yue, Liu Guidong, Wang Xueping, Qian Yiwei, Ding Jianqing, Chen Shengdi, Xiao Qin
Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin Er Road, Shanghai, 200025, China.
J Neuroinflammation. 2017 Feb 20;14(1):38. doi: 10.1186/s12974-017-0795-8.
Microglia in the central nervous system (CNS) were reported to play crucial role in neurodegeneration. Previous studies showed that P2Y6 receptor (P2Y6R) mainly contributed to microglia activation and phagocytosis in CNS. However, the level of P2Y6R in Parkinson's disease (PD) patients is unclear. Therefore, we measured the level of P2Y6R in PD patients and speculated whether it could be a potential biomarker for PD. Given on the basis that P2Y6R was higher in PD patients, we further explored the mechanisms underlying P2Y6R in the pathogenesis of PD.
We tested the expression level of P2Y6R in the peripheral blood mononuclear cells (PBMCs) among 145 PD patients, 170 healthy controls, and 30 multiple system atrophy (MSA) patients. We also used a lipopolysaccharide (LPS)-stimulated microglial cell culture model to investigate (i) the effects of LPS on P2Y6R expression with western blot and RT-PCR, (ii) the effects of LPS on UDP expression using HPLC, (iii) the effects of UDP/P2Y6R signaling on cytokine expression using western blot, RT-PCR, and ELISA, and (iv) the signaling pathways activated by the P2Y6R involved in the neuroinflammation.
Expression levels of P2Y6R in PD patients were higher than healthy controls and MSA patients. P2Y6R could be a good biomarker of PD. P2Y6R was also upregulated in LPS-treated BV-2 cells and involved in proinflammatory cytokine release through an autocrine loop based on LPS-triggered UDP secretion and accelerated neuroinflammatory responses through the ERK1/2 pathway. Importantly, blocking UDP/P2Y6R signaling could reverse these pathological processes.
P2Y6R may be a potential clinical biomarker of PD. Blocking P2Y6R may be a potential therapeutic approach to the treatment of PD patients through inhibition of microglia-activated neuroinflammation.
据报道，中枢神经系统（CNS）中的小胶质细胞在神经退行性变中起关键作用。先前的研究表明，P2Y6受体（P2Y6R）主要促成中枢神经系统中小胶质细胞的激活和吞噬作用。然而，帕金森病（PD）患者中P2Y6R的水平尚不清楚。因此，我们检测了PD患者中P2Y6R的水平，并推测其是否可能是PD的潜在生物标志物。基于PD患者中P2Y6R较高这一情况，我们进一步探讨了P2Y6R在PD发病机制中的潜在机制。
我们检测了145例PD患者、170例健康对照者和30例多系统萎缩（MSA）患者外周血单个核细胞（PBMC）中P2Y6R的表达水平。我们还使用脂多糖（LPS）刺激的小胶质细胞培养模型来研究：（i）LPS对P2Y6R表达的影响（采用蛋白质免疫印迹法和逆转录-聚合酶链反应法）；（ii）LPS对UDP表达的影响（采用高效液相色谱法）；（iii）UDP/P2Y6R信号对细胞因子表达的影响（采用蛋白质免疫印迹法、逆转录-聚合酶链反应法和酶联免疫吸附测定法）；以及（iv）P2Y6R激活的参与神经炎症的信号通路。
PD患者中P2Y6R的表达水平高于健康对照者和MSA患者。P2Y6R可能是PD的良好生物标志物。在LPS处理的BV-2细胞中P2Y6R也上调，并通过基于LPS触发的UDP分泌的自分泌环参与促炎细胞因子释放，并通过细胞外信号调节激酶1/2（ERK1/2）途径加速神经炎症反应。重要的是，阻断UDP/P2Y6R信号可逆转这些病理过程。
P2Y6R可能是PD的潜在临床生物标志物。阻断P2Y6R可能是通过抑制小胶质细胞激活的神经炎症来治疗PD患者的潜在治疗方法。
