PAFR activation of NF-κB p65 or p105 precursor dictates pro- and anti-inflammatory responses during TLR activation in murine macrophages.
PAFR activation of NF-κB p65 or p105 precursor dictates pro- and anti-inflammatory responses during TLR activation in murine macrophages.
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DOI：
10.1038/srep32092
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发表时间：
2016-08-24
影响因子：
4.6
通讯作者：
Jancar S
中科院分区：
文献类型：
--
作者：
Ishizuka EK;Filgueiras LR;Rios FJ;Serezani CH;Jancar S
血小板活化因子受体（PAFR）是一种G蛋白偶联受体（GPCR），与许多疾病有关。Toll样受体（TLR）在形成先天性和适应性免疫应答中起关键作用。在这项研究中，我们研究了PAFR信号是否改变巨噬细胞对TLR 2（Pam 3Cys）、TLR 4（LPS）和TLR 3激动剂Poly（I：C）的反应性。外源性PAF抑制Pam 3Cys和LPS刺激的巨噬细胞产生促炎细胞因子（IL-12 p40、IL-6和TNF-α），增加抗炎细胞因子IL-10，但对Poly（I：C）刺激的巨噬细胞无影响。PAF不影响MyD 88的mRNA表达，提示PAF作用于衔接子下游。PAF抑制LPS诱导的NF-κB p65的磷酸化，并增加NF-κB p105的磷酸化，其在蛋白酶体中被加工成p50亚基。PAF增强IL-10的产生依赖于蛋白酶体加工，而不依赖于NF-κB反式激活结构域。抑制p50可阻断PAF诱导的IL-10的产生。这些发现表明，受损的转录活性的p65亚基和增强的p105磷酸化诱导的PAF负责下调促炎细胞因子和上调IL-10，分别在LPS攻击的巨噬细胞。总之，我们的数据揭示了PAFR在调节巨噬细胞中NF-κB活化中迄今未被认识的作用。
Platelet-activating factor receptor (PAFR) is a G protein-coupled receptor (GPCR) implicated in many diseases. Toll-like receptors (TLRs) play a critical role in shaping innate and adaptive immune responses. In this study, we investigated whether PAFR signaling changes the macrophages responsiveness to agonists of TLR2 (Pam3Cys), TLR4 (LPS), and TLR3 agonist Poly(I:C). Exogenous PAF inhibited the production of pro-inflammatory cytokines (IL-12p40, IL-6, and TNF-α) and increased anti-inflammatory IL-10 in macrophages challenged with Pam3Cys and LPS, but not with Poly (I:C). PAF did not affect mRNA expression of MyD88, suggesting that PAF acts downstream the adaptor. PAF inhibited LPS-induced phosphorylation of NF-κB p65 and increased NF-κB p105 phosphorylation, which is processed in the proteasome to generate p50 subunit. The PAF potentiation of IL-10 production was dependent on proteasome processing but independent of NF-κB transactivation domain. Inhibition of p50 abolished the PAF-induced IL-10 production. These findings indicate that the impaired transcriptional activity of the p65 subunit and the enhanced p105 phosphorylation induced by PAF are responsible for down regulation of pro-inflammatory cytokines and up regulation of IL-10, respectively, in LPS-challenged macrophages. Together, our data unveil a heretofore unrecognized role for PAFR in modulating activation of NF-κB in macrophages.