The pH-responsive PacC transcription factor of Aspergillus fumigatus governs epithelial entry and tissue invasion during pulmonary aspergillosis.
The pH-responsive PacC transcription factor of Aspergillus fumigatus governs epithelial entry and tissue invasion during pulmonary aspergillosis.
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DOI：
10.1371/journal.ppat.1004413
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发表时间：
2014-10
期刊：
影响因子：
6.7
通讯作者：
Bignell EM
中科院分区：
文献类型：
--
作者：
Bertuzzi M;Schrettl M;Alcazar-Fuoli L;Cairns TC;Muñoz A;Walker LA;Herbst S;Safari M;Cheverton AM;Chen D;Liu H;Saijo S;Fedorova ND;Armstrong-James D;Munro CA;Read ND;Filler SG;Espeso EA;Nierman WC;Haas H;Bignell EM
肺上皮的破坏是由霉菌病原菌烟曲霉引起的肺部疾病的一个主要特征。尽管人们普遍认为组织侵袭是由真菌蛋白酶控制的，但烟曲霉突变体缺乏单个或多个酶仍然具有完全侵袭性，这表明在入侵宿主过程中需要其他致病活性。在这项研究中，我们发现并利用了烟曲霉突变体中缺乏ph响应转录因子PacC的一种新的、组织非侵入性的表型。我们的研究揭示了一种新的上皮进入模式，在蛋白酶产生之前以细胞壁依赖的方式发生，并通过Dectin-1 β-葡聚糖受体。ΔpacC突变体在接触介导的上皮进入和蛋白酶表达方面都存在缺陷，并且在白细胞减少小鼠中的致病性显著减弱。我们结合小鼠感染模型、体内转录组学和人类肺泡上皮的体外感染，描绘了影响体外上皮完整性和整个动物组织侵袭的两个主要的、顺序作用的pacc依赖过程。我们证明烟曲霉孢子和芽孢以接触依赖、肌动蛋白依赖、细胞壁依赖和Dectin-1依赖的方式被上皮细胞内化，而ΔpacC突变体在萌发生长过程中异常重塑细胞壁，在体外和体内都无法进入上皮细胞。我们进一步表明，在白细胞减少的哺乳动物肺生长过程中，PacC作为分泌分子的全球转录调节剂，并描绘了侵袭性感染期间表达的分泌基因产物的完整队列。我们的研究揭示了组织进入的组合模式依赖于连续的，机械上不同的肺上皮扰动，并首次证明了Dectin-1阻断在上皮防御中的保护作用。感染ΔpacC突变体对细胞壁活性抗真菌药物过敏，突出了PacC信号作为抗真菌治疗靶点的价值。吸入致病性霉菌烟曲霉的孢子会导致有免疫缺陷的人肺部真菌感染。烟曲霉孢子在免疫功能低下的肺内萌发，产生侵入性生长的细长细胞，称为菌丝。菌丝降解周围的肺组织，这一过程被认为是由分泌的真菌酶引起的；然而，缺乏一种或多种蛋白酶活性的烟曲霉突变体在小鼠疾病模型中保留了完全侵袭性表型。在这里，我们首次报道了一种非侵袭性烟曲霉突变体的发现，该突变体缺乏ph响应转录因子PacC。利用野生型和突变株的全球转录谱分析以及体外肺侵袭试验，我们确定PacC的缺失会导致一种复合的非侵入性表型，其特征是接触介导的上皮进入和蛋白酶表达的缺陷。与上皮进入在促进哺乳动物组织侵袭性疾病中的重要作用一致，PacC突变体在体外和体内均停留在哺乳动物上皮表面。我们的研究开创了宿主和病原体共同参与烟曲霉侵袭上皮的新先例，并支持真菌蛋白酶活性随后或与宿主介导的上皮进入并行作用的模型，为组织侵袭提供了机制基础。
Destruction of the pulmonary epithelium is a major feature of lung diseases caused by the mould pathogen Aspergillus fumigatus. Although it is widely postulated that tissue invasion is governed by fungal proteases, A. fumigatus mutants lacking individual or multiple enzymes remain fully invasive, suggesting a concomitant requirement for other pathogenic activities during host invasion. In this study we discovered, and exploited, a novel, tissue non-invasive, phenotype in A. fumigatus mutants lacking the pH-responsive transcription factor PacC. Our study revealed a novel mode of epithelial entry, occurring in a cell wall-dependent manner prior to protease production, and via the Dectin-1 β-glucan receptor. ΔpacC mutants are defective in both contact-mediated epithelial entry and protease expression, and significantly attenuated for pathogenicity in leukopenic mice. We combined murine infection modelling, in vivo transcriptomics, and in vitro infections of human alveolar epithelia, to delineate two major, and sequentially acting, PacC-dependent processes impacting epithelial integrity in vitro and tissue invasion in the whole animal. We demonstrate that A. fumigatus spores and germlings are internalised by epithelial cells in a contact-, actin-, cell wall- and Dectin-1 dependent manner and ΔpacC mutants, which aberrantly remodel the cell wall during germinative growth, are unable to gain entry into epithelial cells, both in vitro and in vivo. We further show that PacC acts as a global transcriptional regulator of secreted molecules during growth in the leukopenic mammalian lung, and profile the full cohort of secreted gene products expressed during invasive infection. Our study reveals a combinatorial mode of tissue entry dependent upon sequential, and mechanistically distinct, perturbations of the pulmonary epithelium and demonstrates, for the first time a protective role for Dectin-1 blockade in epithelial defences. Infecting ΔpacC mutants are hypersensitive to cell wall-active antifungal agents highlighting the value of PacC signalling as a target for antifungal therapy. Inhaled spores of the pathogenic mould Aspergillus fumigatus cause fungal lung infections in humans having immune defects. A. fumigatus spores germinate within the immunocompromised lung, producing invasively growing, elongated cells called hyphae. Hyphae degrade the surrounding pulmonary tissue, a process thought to be caused by secreted fungal enzymes; however, A. fumigatus mutants lacking one or more protease activities retain fully invasive phenotypes in mouse models of disease. Here we report the first discovery of a non-invasive A. fumigatus mutant, which lacks a pH-responsive transcription factor PacC. Using global transcriptional profiling of wild type and mutant isolates, and in vitro pulmonary invasion assays, we established that loss of PacC leads to a compound non-invasive phenotype characterised by deficits in both contact-mediated epithelial entry and protease expression. Consistent with an important role for epithelial entry in promoting invasive disease in mammalian tissues, PacC mutants remain surface-localised on mammalian epithelia, both in vitro and in vivo. Our study sets a new precedent for involvement of both host and pathogen activities in promoting epithelial invasion by A. fumigatus and supports a model wherein fungal protease activity acting subsequently to, or in parallel with, host-mediated epithelial entry provides the mechanistic basis for tissue invasion.
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Dectin-1介导β-葡聚糖的生物学作用。
DOI：
10.1084/jem.20021890
发表时间：
2003-05-05
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Brown GD;Herre J;Williams DL;Willment JA;Marshall AS;Gordon S
通讯作者：
Gordon S
影响因子：
4.4
作者：
Gomez P;Hackett TL;Moore MM;Knight DA;Tebbutt SJ
通讯作者：
Tebbutt SJ
DOI：
10.2471/blt.11.089441
发表时间：
2011-12-01
期刊：
Bulletin of the World Health Organization: International Journal of Public Health
影响因子：
--
作者：
Denning, David W;Pleuvry, Alex;Cole, Donald C
通讯作者：
Cole, Donald C
影响因子：
3.1
作者：
AMITANI, R;TAYLOR, G;WILSON, R
通讯作者：
WILSON, R
影响因子：
20.3
作者：
Bezerra, LML;Filler, SG
通讯作者：
Filler, SG