کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1929852 | 1050476 | 2012 | 6 صفحه PDF | دانلود رایگان |
Activation of the P2X7 receptor of macrophages plays an important role in inflammation. We recently reported that co-expression of P2X4 receptor with P2X7 receptor facilitates P2X7 receptor-mediated cell death via Ca2+ influx. However, it remained unclear whether P2X4 receptor is involved in P2X7 receptor-mediated inflammatory responses, such as cytokine production. Here, we present evidence that P2X4 receptor modulates P2X7 receptor-dependent inflammatory functions. Treatment of mouse macrophage RAW264.7 cells with 1 mM ATP induced high mobility group box 1 (HMGB1) release and IL-1β production via activation of P2X7 receptor. Knockdown of P2X4 receptor or removal of extracellular Ca2+ suppressed ATP-induced release of both HMGB1 and IL-1β. On the other hand, knockdown of P2X4 receptor or removal of extracellular Ca2+ enhanced P2X7-dependent LC3-II expression (an index of autophagy), suggesting that P2X4 receptor suppresses P2X7-mediated autophagy. Since LC3-II expression was inhibited by pretreatment with antioxidant and NADPH oxidase inhibitor, we examined P2X7-mediated production of reactive oxygen species (ROS). We found that activation of P2X7 receptor-mediated production of ROS was significantly facilitated in P2X4-knockdown cells, suggesting that co-expression of P2X4 receptor with P2X7 receptor may suppress anti-inflammatory function-related autophagy via suppression of ROS production. We conclude that co-expression of P2X4 receptor with P2X7 receptor enhances P2X7-mediated inflammation through both facilitation of release of cytokines and suppression of autophagy.
► Extracellular ATP induces P2X7 receptor-dependent inflammatory events in macrophages.
► P2X4 receptor is co-expressed with P2X7 receptor in macrophages.
► P2X4-Knockdown attenuated P2X7-dependent IL-1β and HMGB1 release.
► P2X4-Knockdown enhanced P2X7-dependent autophagy and ROS generation.
► P2X4 receptor regulates P2X7 receptor-dependent inflammatory functions.
Journal: Biochemical and Biophysical Research Communications - Volume 420, Issue 1, 30 March 2012, Pages 102–107