Toll-like receptors (TLRs) expressed on mast cells are essential for effective host defense against a wide variety of pathogens. Previous studies have demonstrated that both TLR2 agonists Pam3CSK4 and PGN stimulated IL-8 release in human mast cells. To determine the molecular basis for this phenomenon, we utilized human mast cell line LAD2 cells. We found that only the release of IL-8 stimulated by Pam3CSK4 was TLR2-mediated, which was confirmed by specific TLR2 shRNA. Heterotrimeric G proteins have been previously implicated in TLR signaling in macrophages and monocytes. In the current study, we showed that PamCSK4 induced the activation of MAPKs, NF-κB, PI3K-Akt and Ca(2+)-calcineurin-NFAT signaling cascades in LAD2 cells. Go proteins were required for the activation of MAPKs and NF-κB in TLR2 stimulated LAD2 cells. Therefore, the genetic depletion of Gαo proteins also led to the reduction of the release of IL-8 in LAD2 cells. Taken together, the data presented here suggest that TLR2 activation in human mast cells promotes the release of inflammatory mediators via distinct signaling pathways that partially depend on the action of Go proteins.

中文翻译：

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Toll样受体2介导的MAPK和NF-κB激活需要人类肥大细胞中GNAO1依赖性途径。

在肥大细胞上表达的Toll样受体（TLR）对于有效的宿主防御多种病原体至关重要。先前的研究表明，TLR2激动剂Pam3CSK4和PGN均可刺激人肥大细胞中IL-8的释放。为了确定这种现象的分子基础，我们利用了人类肥大细胞系LAD2细胞。我们发现只有受Pam3CSK4刺激的IL-8的释放是TLR2介导的，这一点已通过特异性TLR2 shRNA证实。异源三聚体G蛋白先前已参与巨噬细胞和单核细胞的TLR信号传导。在当前的研究中，我们表明PamCSK4诱导了LAD2细胞中MAPK，NF-κB，PI3K-Akt和Ca（2 +）-钙调神经磷酸酶-NFAT信号级联的激活。Go蛋白是激活TLR2刺激的LAD2细胞中MAPK和NF-κB所必需的。因此，Gαo蛋白的遗传损耗也导致LAD2细胞中IL-8的释放减少。综上所述，此处提供的数据表明，人类肥大细胞中TLR2的激活通过部分依赖于Go蛋白作用的独特信号通路促进炎性介质的释放。