NAD+ and ATP Released from Injured Cells Induce P2X7-Dependent Shedding of CD62L and Externalization of Phosphatidylserine by Murine T Cells
NAD+ and ATP Released from Injured Cells Induce P2X7-Dependent Shedding of CD62L and Externalization of Phosphatidylserine by Murine T Cells
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DOI：
10.4049/jimmunol.0801711
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发表时间：
2009-03-01
影响因子：
4.4
通讯作者：
Koch-Nolte, Friedrich
中科院分区：
文献类型：
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作者：
Scheuplein, Felix;Schwarz, Nicole;Koch-Nolte, Friedrich
细胞外NAD（+）和ATP触发小鼠T细胞上CD 62 L的脱落和磷脂酰丝氨酸的外化。这些事件依赖于P2 X（7）离子通道。虽然ATP作为可溶性配体激活P2 X（7），但NAD（+）对P2 X（7）的门控需要外ADP-核糖基转移酶ART2.2催化ADP-核糖部分从NAD（+）转移到P2 X（7）的Arg 125上。细胞外区室中NAD（+）和ATP的稳态浓度受到高度调节，通常远低于激活P2 X所需的阈值（7）。本研究的目的是确定这些核苷酸的可能内源性来源。我们发现，红细胞裂解释放出足够水平的NAD（+）和ATP，以诱导P2 X激活（7）。稀释红细胞裂解物或在37 ℃下孵育裂解物显示，ATP信号比NAD（+）信号衰减得更快。我们进一步表明，即使在4 ℃下，原代淋巴结和脾细胞的常规制备也能诱导足够浓度的NAD（+）释放，使ART2.2转化为ADP-核糖基酸P2 X（7）。当T细胞返回到37 ℃时，发生P2 X的门控（7），通过大量细胞快速诱导CD 62 L脱落和PS外化。在处死小鼠前10分钟，通过静脉注射替代ART底物乙烯基-NAD或ART 2.2抑制性单结构域Ab，可以防止在制备原代T细胞期间P2 X（7）的“自发”活化。免疫学杂志，2009，182：2898-2908.
Extracellular NAD(+) and ATP trigger the shedding of CD62L and the externalization of phosphatidylserine on murine T cells. These events depend on the P2X(7) ion channel. Although ATP acts as a soluble ligand to activate P2X(7), gating of P2X(7) by NAD(+) requires ecto-ADP-ribosyltransferase ART2.2-catalyzed transfer of the ADP-ribose moiety from NAD(+) onto Arg125 of P2X(7). Steady-state concentrations of NAD(+) and ATP in extracellular compartments are highly regulated and usually are well below the threshold required for activating P2X(7). The goal of this study was to identify possible endogenous sources of these nucleotides. We show that lysis of erythrocytes releases sufficient levels of NAD(+) and ATP to induce activation of P2X(7). Dilution of erythrocyte lysates or incubation of lysates at 37 degrees C revealed that signaling by ATP fades more rapidly than that by NAD(+). We further show that the routine preparation of primary lymph node and spleen cells induces the release of NAD(+) in sufficient concentrations for ART2.2 to ADP-ribosylate P2X(7), even at 4 degrees C. Gating of P2X(7) occurs when T cells are returned to 37 degrees C, rapidly inducing CD62L-shedding and PS-externalization by a substantial fraction of the cells. The "spontaneous" activation of P2X(7) during preparation of primary T cells could be prevented by i.v. injection of either the surrogate ART substrate etheno-NAD or ART2.2-inhibitory single domain Abs 10 min before sacrificing mice. The Journal of Immunology, 2009, 182: 2898-2908.