Inducible expression of human β-defensin 2 by Fusobacterium nucleatum in oral epithelial cells:: Multiple signaling pathways and role of commensal bacteria in innate immunity and the epithelial barrier
Inducible expression of human β-defensin 2 by Fusobacterium nucleatum in oral epithelial cells:: Multiple signaling pathways and role of commensal bacteria in innate immunity and the epithelial barrier
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DOI：
10.1128/iai.68.5.2907-2915.2000
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发表时间：
2000-05-01
影响因子：
3.1
通讯作者：
Dale, DA
中科院分区：
文献类型：
--
作者：
Krisanaprakornkit, S;Kimball, JR;Dale, DA
人牙龈上皮细胞（HGE）表达β-防御素家族的两种抗菌肽，即人β-防御素1（hBD - 1）和hBD - 2，以及有助于先天免疫的细胞因子和趋化因子。在本研究中，对hBD - 2的表达和转录调控进行了检测。具核梭杆菌（一种口腔共生微生物）的细胞壁提取物可诱导hBD - 2 mRNA的表达，而牙龈卟啉单胞菌（一种牙周病原体）的细胞壁提取物则不能。促炎细胞因子肿瘤坏死因子α（TNF - α）和上皮细胞激活剂佛波醇肉豆蔻酸酯（PMA）也可诱导hBD - 2 mRNA的表达。在15个非炎症牙龈组织样本中的14个也检测到hBD - 2 mRNA的表达。通过免疫荧光法在具核梭杆菌细胞壁刺激的人牙龈上皮细胞中检测到hBD - 2肽，这与该刺激物对mRNA的诱导作用一致。动力学分析表明，多种不同的信号通路参与了hBD - 2 mRNA的调控；TNF - α和具核梭杆菌细胞壁可快速诱导hBD - 2 mRNA（2 - 4小时），而PMA刺激则较慢（约10小时）。相比之下，每种刺激物在1小时内均可诱导白细胞介素8（IL - 8）。添加不抑制hBD - 2诱导的抗TNF - α可排除TNF - α作为具核梭杆菌信号传导中介的作用。然而，抑制剂研究表明，具核梭杆菌对hBD - 2 mRNA的刺激需要新的基因转录和新的蛋白质合成。从大肠杆菌和具核梭杆菌中分离的细菌脂多糖对hBD - 2的刺激作用较弱，尽管它们可上调IL - 8 mRNA。总之，我们的研究结果表明，人牙龈上皮细胞中hBD - 2 mRNA通过多种途径可诱导表达，其模式与IL - 8的表达模式不同。我们认为，先天免疫反应的不同方面受到不同的调控，共生生物在刺激黏膜上皮细胞维持有助于内环境稳定和宿主防御的屏障方面具有作用。
Human gingival epithelial cells (HGE) express two antimicrobial peptides of the beta-defensin family, human beta-defensin 1 (hBD-1) and hBD-2, as well as cytokines and chemokines that contribute to innate immunity, In the present study, the expression and transcriptional regulation of hBD-2 was examined. HBD-2 mRNA was induced by cell wall extract of Fusobacterium nucleatum, an oral commensal microorganism, but not by that of Porphyromonas gingivalis, a periodontal pathogen, HBD-2 mRNA was also induced by the proinflammatory cytokine tumor necrosis factor alpha (TNF-alpha) and phorbol myristate acetate (PMA), an epithelial cell activator, HBD-2 mRNA was also expressed in 14 of 15 noninflamed gingival tissue samples. HBD-2 peptide was detected by immunofluorescence in HGE stimulated with F. nucleatum cell wall, consistent with induction of the mRNA by this stimulant. Kinetic analysis indicates involvement of multiple distinct signaling pathways in the regulation of hBD-2 mRNA; TNF-alpha and F. nucleatum cell wall induced hBD-2 mRNA rapidly (2 to 4 h), while PMA stimulation was slower (similar to 10 h). In contrast, each stimulant induced interleukin 8 (IL-8) within 1 h, The role of TNF-alpha as an intermediary in F. nucleatum signaling was ruled out by addition of anti TNF-alpha that did not inhibit hBD-2 induction, However, inhibitor studies show that F. nucleatum stimulation of hBD-2 mRNA requires both new gene transcription and new protein synthesis, Bacterial lipopolysaccharides isolated from Escherichia coli and F, nucleatum were poor stimulants of hBD-2, although they up-regulated IL-8 mRNA. Collectively, our findings show inducible expression of hBD-2 mRNA via multiple pathways in HGE in a pattern that is distinct from that of IL-8 expression. We suggest that different aspects of innate immune responses are differentially regulated and that commensal organisms have a role in stimulating mucosal epithelial cells in maintaining the barrier that contributes to homeostasis and host defense.