Characterization of ATP-gated P2X7 receptors in fish provides new insights into the mechanism of release of the leaderless cytokine interleukin-1β
Characterization of ATP-gated P2X7 receptors in fish provides new insights into the mechanism of release of the leaderless cytokine interleukin-1β
复制标题
DOI：
10.1016/j.molimm.2006.05.015
复制
发表时间：
2007-02-01
影响因子：
3.6
通讯作者：
Mulero, Victoriano
中科院分区：
文献类型：
--
作者：
Lopez-Castejon, Gloria;Young, Mark T.;Mulero, Victoriano
哺乳动物白细胞介素-1 β（IL-1 β）作为生物学上无活性的前体分子产生，其在细胞外ATP激活P2 X（7）受体后被IL-1 β转化酶（ICE）蛋白水解切割成活性形式。尽管大多数IL-1 β基因序列缺乏保守的ICE识别位点，但在非哺乳动物脊椎动物中IL-1 β释放的机制在很大程度上是未知的。在这里，我们克隆了来自硬骨鱼的P2 X（7）受体，并比较了在HEK细胞中表达的这种和其他非哺乳动物P2 X（7）受体的激动剂和拮抗剂谱，以及在表达内源性P2 X（7）受体的海鸟SAF-1细胞中。我们利用这些信息进一步研究了哺乳动物和鱼类P2 X（7）受体诱导的IL-1 β释放的机制。尽管磷脂酰丝氨酸外化和细胞透化后，加入高浓度的BzATP的海鸟白细胞，IL-1 β仍然未加工的细胞内。然而，在HEK 293中异位表达的大鼠P2 X（7）受体与人ICE的激活导致未加工的海鸟IL-1 β的特异性分泌。相比之下，当在HEK 293中表达时，无论是海鸟还是斑马鱼P2 X（7）受体都不能诱导哺乳动物或鱼类IL-1 β的分泌，而含有海鸟P2 X（7）的ATP结合结构域和其大鼠对应物的细胞内区域的嵌合受体则可以。这些发现表明，P2 X（7）受体介导的ICE激活和IL-1 β释放是由不同的下游信号通路引起的，并表明尽管IL-1 β分泌所涉及的机制在整个进化过程中是保守的，但在不同的脊椎动物中，这种细胞因子的分泌选择了不同的炎症信号。(c)2006爱思唯尔有限公司保留所有权利。
Mammalian interleukin-1 beta (IL-1 beta) is produced as a biologically inactive precursor molecule, which is proteolytically cleaved to an active form by IL-1 beta-converting enzyme (ICE) after the activation of P2X(7) receptor by extracellular ATP. The mechanism of IL-1 beta release in non-mammalian vertebrates is largely unknown, although most of the IL-1 beta gene sequences lack a conserved ICE recognition site. Here we have cloned the P2X(7) receptor from the bony fish seabream and compared agonist and antagonist profiles at this and other non-mammalian P2X(7) receptors expressed in HEK cells, as well in seabream SAF-1 cells expressing endogenous P2X(7) receptors. We used this information to further investigate the mechanisms of IL-1 beta release induced by mammalian and fish P2X(7) receptors. Despite phosphatidylserine externalization and cell permeabilization in seabream leukocytes after the addition of high BzATP concentrations, IL-1 beta remained unprocessed within the cell. However, activation of rat P2X(7) receptors ectopically expressed in HEK293 together with human ICE led to the specific secretion of unprocessed seabream IL-1 beta. In contrast, neither seabream nor zebrafish P2X(7) receptors induced the secretion of mammalian or fish IL-1 beta when expressed in HEK293, while a chimeric receptor harboring the ATP-binding domain of seabream P2X(7) and the intracellular region of its rat counterpart did so. These findings indicate that P2X(7) receptor-mediated activation of ICE and release of IL-1 beta result from different downstream signaling pathways and suggest that although the mechanisms involved in IL-1 beta secretion are conserved throughout evolution, distinct inflammatory signals have been selected for the secretion of this cytokine in different vertebrates. (c) 2006 Elsevier Ltd. All rights reserved.