2012年1月19日,据《每日科学》报道,一种在血小板上发现的受体,其作为潜在药物靶标的重要性一直饱受质疑,实际上在药物测试中可能是卓有成就的,根据美国密歇根州立大学的一项新研究。
一个由密歇根州立大学化学系Dana Spence领导的团队揭示了一种分离及测试P2X1受体的方法。通过创建一种新的、简单的方法来研究它,研究团队已解锁了一个许多影响红细胞的疾病(如糖尿病,高血压和囊性纤维变性)潜在的新药物靶标。
研究人员不仅可以从开发新药物方面评估受体,从重新测试现有药物附加到受体起作用方面也可以对受体进行评估。
"科学家们一直在人体内寻找新的'可药性(druggable)'受体,"Spence说。"P2X1受体,长久以来一直被视为在血小板中不重要;我们的研究表明,这不一定是对的。受体是非常活跃的,你需要小心的使用它。"
这项研究发表在本期的《分析方法》(Analytical Methods)上。
血小板的主要工作是通过凝结帮助防止出血,Spence说。它们通过增加血液的粘稠、阻止正常的血流及阻塞血管来工作,但有些疾病如糖尿病或镰状细胞贫血的问题是血小板变得粘稠--甚至在它们不该粘稠的时候。
当血小板的受体打开时,血小板就被激活了,目前研究人员一直将研究重点放在P2Y受体上,这很容易研究。另一方面,并没有想到P2X1受体在血小板激活中发挥了重要的作用,而且它已被证明非常麻烦,因为一旦血液从身体抽出它就变得不再敏感了。
尽管科学家尝试了一对方法来解决这个问题--通过使用不同的添加剂或酶,但结果在研究受体中并没有卓越的成效。
Spence和他的团队发现的是,通过添加一种简单的被称为NF449(最初认为能够阻断受体)的分子,他们在抽血后能够激活血小板中的P2X1受体。
"我们已经发现了一种制备和处理血小板的方法,使我们能够真实可靠地研究受体,"他说。"这项研究开辟了新的研究途径,将允许研究人员和制药公司重新评估这种受体作为'可药性'的靶标。"(生物谷bioon.com)
doi:10.1039/C1AY05530E
PMC:
PMID:
Measuring P2X1 receptor activity in washed platelets in the absence of exogenous apyrase
Kari B. Anderson, Welivitiya Karunarathne, Dana M. Spence
Abstract: Purinergic receptor signaling events in platelets are a major determinant in platelet function. However, investigating the ATP-sensitive P2X1 platelet receptor is difficult due to its rapid desensitization in the washed platelet sample matrix. To minimize desensitization, most studies involving P2X1 activity in washed platelets require apyrase in the sample to reduce matrix ATP levels. Unfortunately, the apyrase will also rapidly degrade any ATP added exogenously during the studies. Here, we describe a method that employs the reported P2X1 inhibitor NF449 to sensitize washed platelets in the absence of any added apyrase. Sensitization is verified by spectrofluorometric determination of Ca2+ entry into the platelets after stimulation with concentrations of ATP ranging from 0.625 μM to 5 μM. Results suggest that sensitization of the P2X1 receptor by NF449 is not necessarily dependent upon the inhibitor concentration, but rather the ratio of the inhibitor to exogenously-added ATP concentrations. With a ratio of ATP agonist to NF440 concentration of 5 : 1, the resulting percent change in fluorescence due to Ca2+ entry into the platelet is 39.3 ± 0.8%; however, at a ratio of 1 : 8 ATP to NF449 the percent change is reduced to 13.1 ± 2.2%. The sensitizing effect is also investigated as a function of time. The results obtained verify that NF449 can behave as a concentration-dependent inhibitor and sensitizer of the platelet P2X1 receptor in washed platelet samples, depending on the ATP concentration in the matrix.