Molica F, Morel S, Meens M J, Denis J-F, Bradfield P F, Penuela S, Zufferey A, Monyer H, Imhof B A, Chanson M, Laird D W, Fontana P, Kwak B R
Brenda R. Kwak, PhD, Department of Pathology and Immunology, Department of Medical Specializations - Cardiology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva/Switzerland, Tel.: +41 22 379 57 37, Fax: +41 22 379 57 46, E-mail:
Thromb Haemost. 2015 Aug;114(2):325-36. doi: 10.1160/TH14-11-0981. Epub 2015 May 7.
Pannexin1 (Panx1) forms ATP channels that play a critical role in the immune response by reinforcing purinergic signal amplification in the immune synapse. Platelets express Panx1 and given the importance of ATP release in platelets, we investigated Panx1 function in platelet aggregation and the potential impact of genetic polymorphisms on Panx1 channels. We show here that Panx1 forms ATP release channels in human platelets and that inhibiting Panx1 channel function with probenecid, mefloquine or specific (10)Panx1 peptides reduces collagen-induced platelet aggregation but not the response induced by arachidonic acid or ADP. These results were confirmed using Panx1-/- platelets. Natural variations have been described in the human Panx1 gene, which are predicted to induce non-conservative amino acid substitutions in its coding sequence. Healthy subjects homozygous for Panx1-400C, display enhanced platelet reactivity in response to collagen compared with those bearing the Panx1-400A allele. Conversely, the frequency of Panx1-400C homozygotes was increased among cardiovascular patients with hyper-reactive platelets compared with patients with hypo-reactive platelets. Exogenous expression of polymorphic Panx1 channels in a Panx-deficient cell line revealed increased basal and stimulated ATP release from cells transfected with Panx1-400C channels compared with Panx1-400A expressing transfectants. In conclusion, we demonstrate a specific role for Panx1 channels in the signalling pathway leading to collagen-induced platelet aggregation. Our study further identifies for the first time an association between a Panx1-400A>C genetic polymorphism and collagen-induced platelet reactivity. The Panx1-400C variant encodes for a gain-of-function channel that may adversely affect atherothrombosis by specifically enhancing collagen-induced ATP release and platelet aggregation.
泛连接蛋白1（Panx1）形成ATP通道，通过增强免疫突触中的嘌呤能信号放大在免疫反应中发挥关键作用。血小板表达Panx1，鉴于ATP释放对血小板的重要性，我们研究了Panx1在血小板聚集中的功能以及基因多态性对Panx1通道的潜在影响。我们在此表明，Panx1在人血小板中形成ATP释放通道，用丙磺舒、甲氟喹或特异性（10）Panx1肽抑制Panx1通道功能可减少胶原蛋白诱导的血小板聚集，但不影响花生四烯酸或ADP诱导的反应。使用Panx1基因敲除血小板证实了这些结果。人类Panx1基因中已描述了自然变异，预计这些变异会在其编码序列中诱导非保守氨基酸取代。与携带Panx1 - 400A等位基因的健康受试者相比，Panx1 - 400C纯合的健康受试者对胶原蛋白的反应显示出血小板反应性增强。相反，与血小板反应性低的患者相比，血小板反应性高的心血管患者中Panx1 - 400C纯合子的频率增加。在Panx缺陷细胞系中外源表达多态性Panx1通道显示，与表达Panx1 - 400A的转染子相比，用Panx1 - 400C通道转染的细胞的基础和刺激ATP释放增加。总之，我们证明了Panx1通道在导致胶原蛋白诱导的血小板聚集的信号通路中的特定作用。我们的研究首次进一步确定了Panx1 - 400A>C基因多态性与胶原蛋白诱导的血小板反应性之间的关联。Panx1 - 400C变体编码一种功能获得性通道，可能通过特异性增强胶原蛋白诱导的ATP释放和血小板聚集对动脉粥样硬化血栓形成产生不利影响。
