Pannexin-1 couples to maitotoxin- and nigericin-induced interleukin-1β release through a dye uptake-independent pathway
Pannexin-1 couples to maitotoxin- and nigericin-induced interleukin-1β release through a dye uptake-independent pathway
复制标题
DOI：
10.1074/jbc.m610351200
复制
发表时间：
2007-01-26
影响因子：
4.8
通讯作者：
Surprenant, Annmarie
中科院分区：
文献类型：
--
作者：
Pelegrin, Pablo;Surprenant, Annmarie
Pannexin-1是一种新近发现的膜蛋白，当异位表达时，它可以作为一个非选择性的孔，对乙锭等染料具有渗透性。在内源性表达ATP门控的P2X(7)受体(P2X(7)R)的巨噬细胞中阻断pAnnin-1可以阻止最初的染料摄取，但不能阻止离子电流，还可以阻止对P2X(7)R激活的白介素1β(IL-1β)的处理和释放。这些结果表明，PAnnexin-1可能是被P2X(7)R激活的半通道，为染料摄取和下游信号传递到IL-1β的加工和释放提供管道。我们通过测量小鼠J774巨噬细胞对P2X(7)R激活以及对毛霉毒素和黑素的反应，对染料摄取和IL-1β的处理和释放进行了研究，这两种药物被认为通过相同的机制诱导IL-1β的释放。这些实验是在一段时间内进行的，在这段时间内，细胞中没有乳酸脱氢酶释放，只检查非细胞溶解途径。P2X(7)R激活可引起染料摄取，通过抑制pannin-1可将其分为两个组分：最初的快速阶段和较慢的pannin-1非依赖性阶段。毛霉毒素诱导的染料摄取不受pannin-1抑制的影响。尼格列星不能诱导染料摄取。抑制pAnnexin-1可阻断caspase-1和IL-1β的处理和释放，以响应所有这三种刺激。因此，尽管pAnnin-1是毛霉毒素、黑素和三磷酸腺苷反应IL-1β释放所必需的，但前两个过程必须有不同于pannin-1半通道激活的机制。
Pannexin-1 is a recently identified membrane protein that can act as a nonselective pore permeable to dyes such as ethidium when ectopically expressed. Blockade of pannexin-1 in macrophage endogenously expressing the ATP-gated P2X(7) receptor (P2X(7)R) blocks the initial dye uptake, but not the ionic current, and also blocks processing and release of interleukin-1 beta (IL-1 beta) in response to P2X(7)R activation. These results suggest that pannexin-1 may be a hemichannel activated by the P2X(7)R to provide the conduit for dye uptake and downstream signaling to processing and release of IL-1 beta. We have pursued this hypothesis by measuring dye uptake and IL-1 beta processing and release in mouse J774 macrophage in response to P2X(7)R activation and to maitotoxin and nigericin, two agents considered to evoke IL-1 beta release via the same mechanism. The experiments were carried out over time periods during which no lactate dehydrogenase was released from cells to examine only noncytolytic pathways. P2X(7)R activation evoked dye uptake that could be separated into two components by pannexin-1 inhibition: an initial rapid phase and a slower pannexin-1-independent phase. Maitotoxin-evoked dye uptake was unaltered by pannexin-1 inhibition. Nigericin did not induce dye uptake. Inhibition of pannexin-1 blocked caspase-1 and IL-1 beta processing and release in response to all three stimuli. Thus, although pannexin-1 is required for IL-1 beta release in response to maitotoxin, nigericin, and ATP, a mechanism distinct from pannexin-1 hemichannel activation must underlie the former two processes.