Pombo Mónica, Lamé Michael W, Walker Naomi J, Huynh Danh H, Tablin Fern
Department of Anatomy, Physiology & Cell Biology, Davis, United States.
Department of Molecular Biosciences, Davis, United States.
Toxicol Lett. 2015 May 19;235(1):28-36. doi: 10.1016/j.toxlet.2015.03.005. Epub 2015 Mar 19.
The role of the aryl hydrocarbon receptor (AhR) in hemostasis has recently gained increased attention. Here, we demonstrate, by qRT-PCR and western blot, that human platelets express both AhR mRNA and AhR protein. AhR protein levels increase in a dose dependent manner when incubated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or omeprazole. Treatment of platelets with puromycin blocks increased AhR protein synthesis in the presence of AhR activators. Additionally, treatment of platelets with either activator results in phosphorylation of p38MAPK and cPLA2, two key signaling molecules in platelet activation pathways. Using the AhR competitive inhibitors alpha naphthoflavone and CH-223191, we show that phosphorylation of p38MAPK is AhR dependent. Further, inhibition of p38MAPK blocks downstream cPLA2 phosphorylation induced by TCDD or omeprazole. Treatment with AhR activators results in platelet priming, as demonstrated by increased platelet aggregation, which is inhibited by AhR antagonists. Our data support a model of the platelet AhR non-genomic pathway in which treatment with AhR activators results in increased expression of the AhR, phosphorylation of p38MAPK and cPLA2, leading to platelet priming in response to agonist.
芳烃受体（AhR）在止血过程中的作用最近受到了越来越多的关注。在此，我们通过qRT-PCR和蛋白质印迹法证明，人血小板表达AhR mRNA和AhR蛋白。当与2,3,7,8-四氯二苯并对二恶英（TCDD）或奥美拉唑孵育时，AhR蛋白水平呈剂量依赖性增加。用嘌呤霉素处理血小板可阻断在AhR激活剂存在下AhR蛋白合成的增加。此外，用任何一种激活剂处理血小板都会导致p38MAPK和cPLA2磷酸化，这是血小板激活途径中的两个关键信号分子。使用AhR竞争性抑制剂α-萘黄酮和CH-223191，我们表明p38MAPK的磷酸化是AhR依赖性的。此外，抑制p38MAPK可阻断由TCDD或奥美拉唑诱导的下游cPLA2磷酸化。用AhR激活剂处理会导致血小板致敏，这通过增加的血小板聚集得到证明，而AhR拮抗剂可抑制这种聚集。我们的数据支持血小板AhR非基因组途径的模型，其中用AhR激活剂处理会导致AhR表达增加、p38MAPK和cPLA2磷酸化，从而导致血小板对激动剂产生致敏反应。
