Pharmacological Characterization of Pannexin-1 Currents Expressed in Mammalian Cells
Pharmacological Characterization of Pannexin-1 Currents Expressed in Mammalian Cells
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DOI：
10.1124/jpet.108.146365
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发表时间：
2009-02-01
影响因子：
3.5
通讯作者：
Surprenant, Annmarie
中科院分区：
文献类型：
--
作者：
Ma, Weihong;Hui, Hui;Surprenant, Annmarie
Pannexin (Panx) 1是一种广泛表达的蛋白，与间隙连接蛋白（connexins）具有结构同源性，但不具有氨基酸同源性。Panx1在哺乳动物细胞中不形成间隙连接，但它可能具有质膜半通道的功能。对哺乳动物细胞中panx1表达的药理特性知之甚少。在这里，我们确定了人类PANX1基因的三个变体。我们在哺乳动物细胞中表达了这些变异和小鼠Panx1，并比较了Panx1诱导的电流。所有人类Panx1变异体和小鼠Panx1显示相同的蛋白表达水平、定位模式和功能特性，尽管功能表达的频率依赖于物种。Panx1电流独立于细胞外或细胞内钙或磷脂酶C转导的变化。我们发现了抑制Panx1电流的化合物，其效价为：carbenoxolone >二钠4,4'-二异硫氰基二苯乙烯-2,2'-二磺酸盐（DIDS）近似于4-乙酰氨基二钠- 4'-异硫氰基二苯乙烯-2,2'-二磺酸盐近似于5-硝基-2-（3-苯基丙胺）苯甲酸> indanyloxyacetic acid 94 >> probenecid >> flufenamic acid = nifluic acid。三磷酸核苷酸（ATP、GTP和UTP）通过独立于嘌呤受体的机制快速、可逆地抑制Panx1电流。当Panx1与嘌呤能P2X(7)受体（P2X(7)R）共表达时，发现DIDS作为P2X(7)R拮抗剂抑制atp诱发电流，但其他化合物均未抑制P2X(7)R电流。这是哺乳动物细胞中Panx1介导电流的第一个详细的药理学特征，并为Panx1作为响应P2X(7)R激活的大分子通道的半通道的假设提供了新的（尽管是矛盾的）线索。
Pannexin (Panx) 1 is a widely expressed protein that shares structural, but not amino acid, homology with gap junction proteins, the connexins. Panx1 does not form gap junctions in mammalian cells, but it may function as a plasma membrane hemichannel. Little is known of the pharmacological properties of panx1 expression in mammalian cells. Here, we identify three variants in the human PANX1 gene. We expressed these variants and mouse Panx1 in mammalian cells and compared Panx1-induced currents. All human Panx1 variants and the mouse Panx1 showed identical protein expression levels, localization patterns, and functional properties, although the frequency of functional expression was species-dependent. Panx1 currents were independent of changes in extracellular or intracellular calcium or phospholipase C transduction. We found compounds that inhibited Panx1 currents with a rank order of potency: carbenoxolone > disodium 4,4'-diisothio-cyanatostilbene-2,2'-disulfonate (DIDS) approximate to disodium 4-acet-amido- 4'-isothiocyanato-stilben-2,2'-disulfonate approximate to 5-nitro-2- (3-phenylpropylamino)benzoic acid > indanyloxyacetic acid 94 >> probenecid >> flufenamic acid = niflumic acid. Triphosphate nucleotides (ATP, GTP, and UTP) rapidly and reversibly inhibited Panx1 currents via mechanism(s) independent of purine receptors. When Panx1 was coexpressed with purinergic P2X(7) receptor (P2X(7)R), DIDS was found to act as a P2X(7)R antagonist to inhibit ATP-evoked currents, but none of the other compounds inhibited P2X(7)R currents. This is the first detailed pharmacological characterization of Panx1-mediated currents in mammalian cells and sheds new, although contradictory, light on the hypothesis that Panx1 acts as a hemichannel to allow passage of large molecules in response to P2X(7)R activation.