Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, Bethesda, MD, USA.
Nat Microbiol. 2018 Jan;3(1):53-61. doi: 10.1038/s41564-017-0059-5. Epub 2017 Nov 13.
Oral epithelial cells discriminate between pathogenic and non-pathogenic stimuli, and only induce an inflammatory response when they are exposed to high levels of a potentially harmful microorganism. The pattern recognition receptors (PRRs) in epithelial cells that mediate this differential response are poorly understood. Here, we demonstrate that the ephrin type-A receptor 2 (EphA2) is an oral epithelial cell PRR that binds to exposed β-glucans on the surface of the fungal pathogen Candida albicans. Binding of C. albicans to EphA2 on oral epithelial cells activates signal transducer and activator of transcription 3 and mitogen-activated protein kinase signalling in an inoculum-dependent manner, and is required for induction of a proinflammatory and antifungal response. EphA2 mice have impaired inflammatory responses and reduced interleukin-17 signalling during oropharyngeal candidiasis, resulting in more severe disease. Our study reveals that EphA2 functions as a PRR for β-glucans that senses epithelial cell fungal burden and is required for the maximal mucosal inflammatory response to C. albicans.
口腔上皮细胞能够区分致病和非致病刺激物,只有在暴露于高水平的潜在有害微生物时才会引发炎症反应。目前对于介导这种差异反应的上皮细胞模式识别受体(PRRs)了解甚少。本研究证明,表皮生长因子受体 A2(EphA2)是口腔上皮细胞的 PRR,可与真菌病原体白色念珠菌表面暴露的β-葡聚糖结合。白色念珠菌与口腔上皮细胞上的 EphA2 结合,以接种物依赖性方式激活转录激活因子 3 和丝裂原活化蛋白激酶信号通路,这对于诱导促炎和抗真菌反应是必需的。EphA2 缺失小鼠在口咽念珠菌病期间的炎症反应受损,白细胞介素-17 信号通路减少,导致疾病更严重。本研究揭示了 EphA2 作为β-葡聚糖的 PRR 发挥作用,可感知上皮细胞的真菌负担,是口腔对白色念珠菌最大程度的黏膜炎症反应所必需的。