The innate immune molecule, NOD1, regulates direct killing of Helicobacter pylori by antimicrobial peptides
The innate immune molecule, NOD1, regulates direct killing of Helicobacter pylori by antimicrobial peptides
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DOI：
10.1111/j.1462-5822.2009.01421.x
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发表时间：
2010-05-01
影响因子：
3.4
通讯作者：
Ferrero, Richard L.
中科院分区：
文献类型：
--
作者：
Grubman, Alexandra;Kaparakis, Maria;Ferrero, Richard L.
P&gT；细胞内天然免疫分子NOD1识别通过幽门螺杆菌CAG致病岛(CagPAI)运送到上皮细胞的肽聚糖(PG)，并参与宿主对cagPAI+H.Pylori细菌的防御。为了进一步阐明NOD1在宿主防御中的作用，我们在两个上皮细胞系中研究了NOD1对人β-防御素(DEFBs)的依赖调节。我们的发现表明，在HEK293细胞中，DEFB4和DEFB103的表达需要通过cagPAI+细菌或内化PG激活NOD1。为了研究DEFB4和DEFB103对细胞类型的特异性诱导，我们建立了稳定的NOD1‘基因敲除’(KD)细胞和对照AGS细胞。报告基因分析和RT-PCR分析表明，在AGS细胞中只有DEFB4以NOD1/cagPAI依赖的方式被诱导。此外，在cagPAI+H.Pylori刺激下，AGS对照细胞的培养上清液显著减少H.SiRNA研究证实，人β-防御素2(HBD-2)而不是HBD-3有助于AGS细胞上清液对幽门螺杆菌的抗菌活性。本研究首次证实了NOD1和HbD-2参与了上皮细胞对幽门螺杆菌的直接杀伤，并证实了NOD1在cagPAI+Hp感染的宿主防御机制中的重要性。
P>The cytosolic innate immune molecule, NOD1, recognizes peptidoglycan (PG) delivered to epithelial cells via the Helicobacter pylori cag pathogenicity island (cagPAI), and has been implicated in host defence against cagPAI+H. pylori bacteria. To further clarify the role of NOD1 in host defence, we investigated NOD1-dependent regulation of human beta-defensins (DEFBs) in two epithelial cell lines. Our findings identify that NOD1 activation, via either cagPAI+ bacteria or internalized PG, was required for DEFB4 and DEFB103 expression in HEK293 cells. To investigate cell type-specific induction of DEFB4 and DEFB103, we generated stable NOD1 'knockdown' (KD) and control AGS cells. Reporter gene assay and RT-PCR analyses revealed that only DEFB4 was induced in an NOD1-/cagPAI-dependent fashion in AGS cells. Moreover, culture supernatants from AGS control, but not AGS NOD1 KD cells, stimulated with cagPAI+H. pylori, significantly reduced H. pylori bacterial numbers. siRNA studies confirmed that human beta-defensin 2 (hBD-2), but not hBD-3, contributes to the antimicrobial activity of AGS cell supernatants against H. pylori. This study demonstrates, for the first time, the involvement of NOD1 and hBD-2 in direct killing of H. pylori bacteria by epithelial cells and confirms the importance of NOD1 in host defence mechanisms against cagPAI+H. pylori infection.