Department of Biochemistry, McGill University, Montréal, Canada.
Immunobiology. 2011 Dec;216(12):1274-85. doi: 10.1016/j.imbio.2011.06.008. Epub 2011 Jun 30.
The nucleotide-binding oligomerization domain (Nod)-like receptor (NLR) family member Naip5 plays an essential role in restricting Legionella pneumophila growth inside primary macrophages. Upon interaction with bacterial flagellin, the intracellular receptor Naip5 forms a multi-protein complex, the inflammasome, which activation has a protective role against infection. The A/J mouse strain carries a Naip5 allele (Naip5(A/J)), which renders its macrophages susceptible to Legionella infection. However, Naip5(A/J) is still competent for inflammasome activation suggesting that an as yet unidentified signaling pathway located downstream of Naip5 and defective in Naip5(A/J) macrophages regulates macrophage defenses against Legionella. Therefore, transcriptional profiling experiments with macrophages from C57BL/6J mice (B6), and from congenic mice (BcA75) carrying the partial loss-of-function A/J-derived allele (Naip5(A/J)) on a B6 background, infected or not with wild-type L. pneumophila or flagellin-deficient mutant were carried out to identify genes regulated by flagellin and by Naip5. Both the Legionella infection per se and the presence of flagellin had very strong effects on transcriptional responses of macrophages, 4h following infection, including modulation of cellular pathways associated with inflammatory response and cell survival. On the other hand, the presence of wild type or partial loss of function allele (Naip5(A/J)) at Naip5 did not cause large effects on transcriptional responses of macrophages to infection. We also examined in L. pneumophila infected macrophages, the effect of Naip5 alleles on expression and phosphorylation of 524 phosphoproteins, kinases and phosphatases involved in cell proliferation, immune response, stress and apoptosis. Naip5 alleles had an effect on the TLR-Il1R signaling pathway, the cell cycle and the caveolin-mediated response to pathogen. The results of transcriptome and proteome analyses were organized into cellular pathways in macrophages that are modulated in response to Legionella infection.
核苷酸结合寡聚化结构域（Nod）样受体（NLR）家族成员 Naip5 在外周血单个核细胞中对限制嗜肺军团菌的生长起着至关重要的作用。在与细菌鞭毛蛋白相互作用后，细胞内受体 Naip5 形成一个多蛋白复合物，即炎症小体，该复合物的激活对感染具有保护作用。A/J 小鼠携带一种 Naip5 等位基因（Naip5(A/J)），使其巨噬细胞易受军团菌感染。然而，Naip5(A/J)仍然能够激活炎症小体，这表明 Naip5 下游的一个尚未确定的信号通路在 Naip5(A/J)巨噬细胞中失活，调节巨噬细胞对军团菌的防御。因此，用 C57BL/6J 小鼠（B6）的巨噬细胞以及在 B6 背景上携带部分丧失功能的 A/J 衍生等位基因（Naip5(A/J)）的同源基因小鼠（BcA75）进行了感染或未感染野生型嗜肺军团菌或鞭毛蛋白缺陷突变体的转录谱实验，以鉴定受鞭毛蛋白和 Naip5 调节的基因。军团菌感染本身和鞭毛蛋白的存在对感染后 4 小时的巨噬细胞转录反应有很强的影响，包括调节与炎症反应和细胞存活相关的细胞通路。另一方面，Naip5 存在野生型或部分丧失功能等位基因（Naip5(A/J)）对巨噬细胞对感染的转录反应没有产生很大的影响。我们还研究了在嗜肺军团菌感染的巨噬细胞中，Naip5 等位基因对参与细胞增殖、免疫反应、应激和凋亡的 524 个磷酸化蛋白、激酶和磷酸酶的表达和磷酸化的影响。Naip5 等位基因对 TLR-Il1R 信号通路、细胞周期和病原体的 caveolin 介导反应有影响。转录组和蛋白质组分析的结果被组织成对军团菌感染有反应的巨噬细胞中的细胞途径。
