Roy Sanhita, Karmakar Mausita, Pearlman Eric
From the Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44095.
J Biol Chem. 2014 Jan 10;289(2):1174-82. doi: 10.1074/jbc.M113.523167. Epub 2013 Nov 25.
In the current study, we examined the role of CD14 in regulating LPS activation of corneal epithelial cells and Pseudomonas aeruginosa corneal infection. Our findings demonstrate that LPS induces Toll-like receptor 4 (TLR4) internalization in corneal epithelial cells and that blocking with anti-CD14 selectively inhibits TLR4 endocytosis, spleen tyrosine kinase (Syk) and IRF3 phosphorylation, and production of CCL5/RANTES and IFN-β, but not IL-8. Using a murine model of P. aeruginosa corneal infection, we show that although infected CD14(-/-) corneas produce less CCL5, they exhibit significantly increased CXC chemokine production, neutrophil recruitment to the corneal stroma, and bacterial clearance than C57BL/6 mice. We conclude that CD14 has a critical role in mediating TLR4 signaling through IRF3 in resident corneal epithelial cells and macrophages and thereby modulates TLR4 cell surface activation of the MyD88/NF-κB/AP-1 pathway and production of CXC chemokines and neutrophil infiltration to infected tissues.
在本研究中，我们检测了CD14在调节角膜上皮细胞的脂多糖（LPS）激活及铜绿假单胞菌角膜感染中的作用。我们的研究结果表明，LPS可诱导角膜上皮细胞中Toll样受体4（TLR4）内化，并且用抗CD14阻断可选择性抑制TLR4内吞、脾酪氨酸激酶（Syk）和干扰素调节因子3（IRF3）磷酸化以及CCL5/趋化因子配体1（RANTES）和干扰素-β（IFN-β）的产生，但不影响白细胞介素-8（IL-8）。使用铜绿假单胞菌角膜感染的小鼠模型，我们发现尽管感染的CD14基因敲除（CD14(-/-)）角膜产生的CCL5较少，但与C57BL/6小鼠相比，它们的CXC趋化因子产生显著增加，中性粒细胞向角膜基质募集以及细菌清除能力增强。我们得出结论，CD14在常驻角膜上皮细胞和巨噬细胞中通过IRF3介导TLR4信号传导中起关键作用，从而调节MyD88/核因子κB（NF-κB）/激活蛋白-1（AP-1）途径的TLR4细胞表面激活以及CXC趋化因子的产生和中性粒细胞向感染组织的浸润。
