ATP, NAD+, and nucleic acids are abundant purines that, in addition to having critical intracellular functions, have evolved extracellular roles as danger signals released in response to cell lysis, apoptosis, degranulation, or membrane pore formation. In general ATP and NAD+ have excitatory and adenosine has anti-inflammatory effects on immune cells. This review focuses on recent advances in our understanding of purine release mechanisms, ectoenzymes that metabolize purines (CD38, CD39, CD73, ENPP1, and ENPP2/autotaxin), and signaling by key P2 purinergic receptors (P2X7, P2Y2, and P2Y12). In addition to metabolizing ATP or NAD+, some purinergic ectoenzymes metabolize other inflammatory modulators, notably lysophosphatidic acid and cyclic GMP-AMP (cGAMP). Also discussed are extracellular signaling effects of NAD+ mediated by ADP-ribosylation, and epigenetic effects of intracellular adenosine mediated by modification of S-adenosylmethionine-dependent DNA methylation.

中文翻译：

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嘌呤的释放，代谢和炎症反应中的信号传递。

ATP，NAD +和核酸是丰富的嘌呤，除了具有关键的细胞内功能外，还已经发展出细胞外作用，作为响应细胞裂解，细胞凋亡，脱粒或膜孔形成而释放的危险信号。通常，ATP和NAD +具有兴奋性，腺苷对免疫细胞具有抗炎作用。这篇综述着重于我们对嘌呤释放机制，代谢嘌呤的外切酶（CD38，CD39，CD73，ENPP1和ENPP2 / autotaxin）以及关键的P2嘌呤能受体（P2X7，P2Y2和P2Y12）的信号传导的最新进展。除代谢ATP或NAD +外，一些嘌呤能外切酶还代谢其他炎症调节剂，尤其是溶血磷脂酸和环状GMP-AMP（cGAMP）。还讨论了由ADP-核糖基化介导的NAD +的细胞外信号转导作用，