Distinct roles for Dectin-1 and TLR4 in the pathogenesis of Aspergillus fumigatus keratitis.
Distinct roles for Dectin-1 and TLR4 in the pathogenesis of Aspergillus fumigatus keratitis.
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DOI：
10.1371/journal.ppat.1000976
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发表时间：
2010-07-01
期刊：
影响因子：
6.7
通讯作者：
Pearlman E
中科院分区：
文献类型：
--
作者：
Leal SM Jr;Cowden S;Hsia YC;Ghannoum MA;Momany M;Pearlman E
曲霉菌属是世界范围内角膜溃疡的主要原因，导致免疫功能正常个体的视力受损和失明。为了加深我们对曲霉菌性角膜炎发病机制的理解，我们建立了一种小鼠模型，其中表达红色荧光蛋白（RFP）的A。将烟曲霉（Af293.1RFP）分生孢子注射到角膜基质中，并随时间跟踪疾病进展和真菌存活。使用Mafia小鼠，其中表达c-fms的巨噬细胞和树突状细胞可以被诱导经历凋亡，我们证明了驻留角膜巨噬细胞的存在对于IL-1β和CXCL 1/KC的产生以及中性粒细胞和单核细胞向角膜基质中的募集是必不可少的。我们发现β-葡聚糖在角膜基质中萌发的分生孢子和菌丝上高度表达，并且Dectin-1和磷酸化Syk在感染的角膜中均上调。此外，我们发现，与对照小鼠相比，感染的Dectin-1−/−角膜会损害IL-1β和CXCL 1/KC的产生，导致细胞浸润和真菌清除减少，特别是在感染表达高β-葡聚糖的临床分离株期间。与Dectin 1−/−小鼠相反，细胞浸润到受感染的TLR 2 −/−、TLR 4 −/−和MD-2−/−小鼠角膜中没有受损，表明这些受体在细胞募集中没有作用;然而，真菌杀伤在TLR 4 −/−小鼠中显著减少，但在TLR 2 −/−或MD-2−/−小鼠中则没有。我们还发现TRIF−/−和TIRAP−/−小鼠没有表现出杀真菌缺陷，但MyD 88 −/−和IL-1 R1 −/−小鼠无法调节真菌生长。总之，这些数据与烟曲霉萌发分生孢子上的β-葡聚糖激活角膜巨噬细胞上的Dectin-1以产生IL-1β和CXCL 1的模型一致，后者与IL-1 R1/MyD 88依赖性激活一起导致中性粒细胞募集到角膜基质和TLR 4依赖性真菌杀伤。丝状真菌（包括曲霉菌属）的角膜感染是美国南部和全世界视力受损和失明的常见原因。在印度和中国，当真菌孢子（分生孢子）造成创伤后感染时，收获季节的发病率大大增加。与肺曲霉病不同，角膜炎发生在免疫功能正常的个体中。为了表征宿主反应，我们将表达红色荧光的烟曲霉分生孢子注射到透明的小鼠角膜中，并表明细胞因子的产生、中性粒细胞和单核细胞向角膜基质的募集以及真菌杀伤依赖于巨噬细胞和树突状细胞的存在以及β-葡聚糖受体Dectin-1的表达。我们还发现，真菌杀伤，但不是细胞浸润，是依赖于LPS受体TLR 4的表达。此外，我们证明IL-1 R1和MyD 88调节曲霉菌角膜炎中的中性粒细胞募集和真菌杀伤，而TLR 4相关的衔接分子TRIF和TIRAP没有作用。总之，这些发现确定了对这些生物体的先天免疫应答的特定介质，这些生物体调节疾病严重程度和曲霉菌的存活，可能具有作为治疗干预靶点的潜在应用。
Aspergillus species are a major worldwide cause of corneal ulcers, resulting in visual impairment and blindness in immunocompetent individuals. To enhance our understanding of the pathogenesis of Aspergillus keratitis, we developed a murine model in which red fluorescent protein (RFP)-expressing A. fumigatus (Af293.1RFP) conidia are injected into the corneal stroma, and disease progression and fungal survival are tracked over time. Using Mafia mice in which c-fms expressing macrophages and dendritic cells can be induced to undergo apoptosis, we demonstrated that the presence of resident corneal macrophages is essential for production of IL-1β and CXCL1/KC, and for recruitment of neutrophils and mononuclear cells into the corneal stroma. We found that β-glucan was highly expressed on germinating conidia and hyphae in the cornea stroma, and that both Dectin-1 and phospho-Syk were up-regulated in infected corneas. Additionally, we show that infected Dectin-1−/− corneas have impaired IL-1β and CXCL1/KC production, resulting in diminished cellular infiltration and fungal clearance compared with control mice, especially during infection with clinical isolates expressing high β-glucan. In contrast to Dectin 1−/− mice, cellular infiltration into infected TLR2−/−, TLR4−/−, and MD-2−/− mice corneas was unimpaired, indicating no role for these receptors in cell recruitment; however, fungal killing was significantly reduced in TLR4−/− mice, but not TLR2−/− or MD-2−/− mice. We also found that TRIF−/− and TIRAP−/− mice exhibited no fungal-killing defects, but that MyD88−/− and IL-1R1−/− mice were unable to regulate fungal growth. In conclusion, these data are consistent with a model in which β-glucan on A.fumigatus germinating conidia activates Dectin-1 on corneal macrophages to produce IL-1β, and CXCL1, which together with IL-1R1/MyD88-dependent activation, results in recruitment of neutrophils to the corneal stroma and TLR4-dependent fungal killing. Corneal infection with filamentous fungi, including Aspergillus species, is a common cause of visual impairment and blindness in the southern USA and worldwide. The incidence in India and China greatly increases during harvest season when infection occurs after traumatic injury with fungal spores (conidia). In contrast to pulmonary aspergillosis, keratitis occurs in immunocompetent individuals. To characterize the host response, we injected Aspergillus fumigatus conidia expressing red fluorescence into the transparent mouse cornea, and showed that cytokine production, neutrophil and monocyte recruitment to the corneal stroma and fungal killing is dependent on the presence of macrophages and dendritic cells, and on expression of the β-glucan receptor Dectin-1. We also found that fungal killing, but not cellular infiltration, is dependent on expression of the LPS receptor TLR4. In addition, we demonstrate that IL-1R1 and MyD88 regulate neutrophil recruitment and fungal killing in Aspergillus keratitis, whereas TLR4 associated adaptor molecules TRIF and TIRAP have no role. Together, these findings identify specific mediators of the innate immune response to these organisms that regulate disease severity and survival of Aspergillus that may have potential application as targets for therapeutic intervention.
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DOI：
10.1056/nejmoa0802629
发表时间：
2008-10-23
期刊：
The New England journal of medicine
影响因子：
--
作者：
Bochud PY;Chien JW;Marr KA;Leisenring WM;Upton A;Janer M;Rodrigues SD;Li S;Hansen JA;Zhao LP;Aderem A;Boeckh M
通讯作者：
Boeckh M
影响因子：
4.4
作者：
Bellocchio, S;Montagnoli, C;Romani, L
通讯作者：
Romani, L
DOI：
10.4049/jimmunol.0803505
发表时间：
2009-03-01
期刊：
Journal of immunology (Baltimore, Md. : 1950)
影响因子：
--
作者：
Chinnery HR;Carlson EC;Sun Y;Lin M;Burnett SH;Perez VL;McMenamin PG;Pearlman E
通讯作者：
Pearlman E
影响因子：
120.7
作者：
Chang, Douglas C.;Grant, Gavin B.;Park, Benjamin J.
通讯作者：
Park, Benjamin J.
影响因子：
4.4
作者：
Allart, S;Lulé, J;Davrinche, C
通讯作者：
Davrinche, C