Eudy Brandon J, da Silva Robin P
Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL, United States.
University of Manitoba, 745 Bannatyne Avenue, Winnipeg, Manitoba, R3E 0J9, Canada.
Mol Immunol. 2021 Apr;132:1-7. doi: 10.1016/j.molimm.2021.01.018. Epub 2021 Jan 29.
Macrophages perform the fundamental function of sensing cellular damage, initiating and mediating immune response and tissue repair. Adenine nucleotides are in relatively high abundance in cells and are released from cells during tissue damage that are converted to adenosine in the extracellular environment. The A, A, A and A adenosine receptors serve to regulate immune function. Despite characterization of the adenosine receptors, a comprehensive examination of adenosine receptor signaling in THP-1 macrophage cells has not been done. Moreover, previous studies employed chemical agonists and antagonists that have the potential for off-target affects. Here we systematically knockdown each of the four known adenosine receptors in THP-1 macrophages using validated siRNA and investigated their function under LPS stimulation. We demonstrate that the A receptor is required for adenosine-stimulated IL-10 and IL-1β secretion indicating an important role of this receptor during resolution of inflammation and tissue repair in these cells. The A and A receptor were required for IL-6 and IL-1β secretion showing a net pro-inflammatory role for these receptors. Finally, we present the novel finding that THP-1 macrophages lacking the A receptor undergo pyroptosis when exposed to LPS, demonstrating a novel role of the A receptor in regulation of programmed cell death during inflammation. This work underscores the fundamental importance of adenosine signaling and provides insight into the independent roles of the adenosine receptors in modulating cytokine signaling.
巨噬细胞执行感知细胞损伤、启动和介导免疫反应以及组织修复的基本功能。腺嘌呤核苷酸在细胞中相对大量存在，并在组织损伤期间从细胞中释放出来，在细胞外环境中转化为腺苷。A1、A2A、A2B和A3腺苷受体用于调节免疫功能。尽管对腺苷受体进行了表征，但尚未对THP-1巨噬细胞中的腺苷受体信号传导进行全面研究。此外，先前的研究使用了可能产生脱靶效应的化学激动剂和拮抗剂。在这里，我们使用经过验证的小干扰RNA（siRNA）在THP-1巨噬细胞中系统地敲低四种已知的腺苷受体，并研究它们在脂多糖（LPS）刺激下的功能。我们证明，腺苷刺激的白细胞介素-10（IL-�10）和白细胞介素-1β（IL-1β）分泌需要A2B受体，表明该受体在这些细胞的炎症消退和组织修复过程中起重要作用。IL-6和IL-1β分泌需要A2A和A3受体，表明这些受体具有促炎作用。最后，我们提出了一个新发现，即缺乏A3受体的THP-1巨噬细胞在暴露于LPS时会发生细胞焦亡，这表明A3受体在炎症期间程序性细胞死亡的调节中具有新作用。这项工作强调了腺苷信号传导的根本重要性，并深入了解了腺苷受体在调节细胞因子信号传导中的独立作用。
