LPS potentiates nucleotide-induced inflammatory gene expression in macrophages via the upregulation of P2Y₂ receptor

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• 作者：So Young Eun ; Jihye Seo ; Sang Won Park ; Jae Heun Lee ; Ki Churl Chang ; Hye Jung Kim
• 关键词：ANOVA ; analysis of variance ; COX-2 ; cyclooxygenase-2 ; HEPES ; N-(2-hydroxyethyl)piperazine-N-2-ethanesulfonic acid ; iNOS ; inducible nitric oxide synthase ; LPS ; lipopolysaccharide ; NO ; nitric oxide ; PI3K ; phosphatidylinositol 3-kinase ; PKC ; protein kinase C ; PDK ; phosphoinositide-dependent kinase ; PGE2 ; prostaglandin E2 ; P2Y2R ; P2Y2 receptor ; RT-PCR ; reverse transcription-polymerase chain reaction ; SDS-PAGE ; sodium dodecyl sulfate-polyacrylamide gel electrophoresis ; TBS-T ; Tris-buffered saline-Twe
• 刊名：International Immunopharmacology
• 出版年：February, 2014
• 年：2014
• 卷：18
• 期：2
• 页码：270-276
• 全文大小：946 K

文摘

Sepsis is a severe systemic inflammatory response that is associated with high morbidity and mortality. A previous study using an animal model of sepsis showed that survival was significantly lower in WT mice than in P2Y₂ receptor (P2Y₂R)-deficient mice, suggesting that P2Y₂R plays a role in septic death. We therefore investigated the role of P2Y₂R in the inflammatory responses of RAW264.7 murine macrophages to LPS. LPS time-dependently upregulated P2Y₂R mRNA levels, with a prominent increase observed at 4 h. In addition, LPS increased ATP release in a time dependent manner (5-120 min post LPS treatment). Accordingly, we pretreated cells with LPS for 4 h to induce P2Y₂R expression and then stimulated the cells with UTP or ATP for 16 h. Interestingly, ATP- or UTP-dependent P2Y₂R activation in LPS-pretreated cells resulted in dramatically enhanced HMGB1 secretion, COX-2 and iNOS expression, and furthermore PGE₂ and NO production compared to LPS treatment alone (4 h) or ATP or UTP treatment alone (16 h), an effect that was inhibited by P2Y₂R silencing. In addition, these increases in HMGB1 secretion, COX-2 and iNOS expression and PGE₂ and NO production commonly involved the JNK, PKC and PDK pathways. Taken together, these data demonstrate that LPS-dependent upregulation of P2Y₂R plays a critical role in facilitating the inflammatory responses induced by LPS.