Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland.
Cell Microbiol. 2017 Dec;19(12). doi: 10.1111/cmi.12770. Epub 2017 Aug 17.
Metal restriction imposed by mammalian hosts during an infection is a common mechanism of defence to reduce or avoid the pathogen infection. Metals are essential for organism survival due to its involvement in several biological processes. Aspergillus fumigatus causes invasive aspergillosis, a disease that typically manifests in immunocompromised patients. A. fumigatus PpzA, the catalytic subunit of protein phosphatase Z (PPZ), has been recently identified as associated with iron assimilation. A. fumigatus has 2 high-affinity mechanisms of iron acquisition during infection: reductive iron assimilation and siderophore-mediated iron uptake. It has been shown that siderophore production is important for A. fumigatus virulence, differently to the reductive iron uptake system. Transcriptomic and proteomic comparisons between ∆ppzA and wild-type strains under iron starvation showed that PpzA has a broad influence on genes involved in secondary metabolism. Liquid chromatography-mass spectrometry under standard and iron starvation conditions confirmed that the ΔppzA mutant had reduced production of pyripyropene A, fumagillin, fumiquinazoline A, triacetyl-fusarinine C, and helvolic acid. The ΔppzA was shown to be avirulent in a neutropenic murine model of invasive pulmonary aspergillosis. PpzA plays an important role at the interface between iron starvation, regulation of SM production, and pathogenicity in A. fumigatus.
在感染期间,哺乳动物宿主施加的金属限制是一种常见的防御机制,可减少或避免病原体感染。由于金属参与了许多生物过程,因此对生物体的生存至关重要。烟曲霉会引起侵袭性曲霉病,这种疾病通常发生在免疫功能低下的患者中。蛋白磷酸酶 Z(PPZ)的催化亚基 PpzA 最近被确定与铁同化有关。烟曲霉在感染过程中有 2 种高亲和力的铁摄取机制:还原性铁同化和铁载体介导的铁摄取。已经表明,铁载体的产生对于烟曲霉的毒力很重要,与还原性铁摄取系统不同。在缺铁条件下,与野生型菌株相比,ΔppzA 和野生型菌株之间的转录组和蛋白质组比较表明,PpzA 对涉及次级代谢的基因有广泛的影响。在标准和缺铁条件下的液相色谱-质谱分析证实,ΔppzA 突变体产生的吡嗪吡咯烯 A、 fumagillin、fumiquinazoline A、三乙酰 fusarinine C 和 helvolic acid 减少。在中性粒细胞减少的侵袭性肺曲霉病啮齿动物模型中,ΔppzA 表现出无毒性。PpzA 在烟曲霉中铁饥饿、SM 产生调控和致病性之间的界面中发挥着重要作用。