Abstract:
Aspergillus fumigatus is the leading cause of life-threatening invasive mold infections in immunocompromised individuals. This ubiquitous saprophyte possesses several natural attributes allowing it to evade the immune system, including the ability to withstand high toxic Cu concentrations within the phagosomes of macrophages and neutrophils. We previously established that at high levels, Cu binds and activates the A. fumigatus transcription factor AceA, which upregulates the expression of the Cu exporter CrpA to expel excess Cu. Deletion of aceA or crpA result in extreme Cu sensitivity and attenuated virulence.To identify other elements participating in resistance to Cu, we performed a genome-wide analysis of the transcriptome by RNAseq to analyze the AceA-dependent response of A. fumigatus to excess Cu. We deleted key genes whose transcription was strongly upregulated by high Cu, including those encoding homologs of the three Cu chaperones cox17, atx1 and ccs1. Detailed analysis of these genes indicates that in A. fumigatus, cox17 is an essential gene with a possible role in respiration, the atxA gene product participates in reductive iron uptake and ccsA encodes the Cu chaperone activating A. fumigatus Sod1. Interestingly, although the ccsA-null strain was extremely sensitive to high Cu and oxidative stress, it was not attenuated in virulence in a mouse model of invasive pulmonary aspergillosis.Our work provides (i) a detailed view of the genome-wide transcriptional response of A. fumigatus to excess Cu, (ii) identification of the AceA-dependent transcriptome and (iii) analysis of the roles of the three Cu chaperones cox17, atxA and ccsA.
摘要:
烟曲霉是免疫受损个体中危及生命的侵袭性霉菌感染的主要原因。这种无处不在的腐生植物具有几种自然属性,可以逃避免疫系统,包括耐受巨噬细胞和嗜中性粒细胞吞噬体内高毒性Cu浓度的能力。我们之前确定在高层,Cu结合并激活烟曲霉转录因子AceA,这上调了Cu出口国CrpA的表达以排出过量的Cu。aceA或crpA的缺失导致极端的Cu敏感性和减弱的毒力。为了识别参与铜抗性的其他元素,我们通过RNAseq对转录组进行了全基因组分析,以分析烟曲霉对过量Cu的AceA依赖性反应。我们删除了转录被高Cu强烈上调的关键基因,包括编码三个Cu伴侣cox17,atx1和ccs1的同源物的那些。对这些基因的详细分析表明,在烟曲霉中,cox17是一种重要的基因,可能在呼吸中起作用,atxA基因产物参与还原性铁摄取,ccsA编码激活烟曲霉Sod1的Cu伴侣。有趣的是,尽管ccsA-null菌株对高Cu和氧化应激极为敏感,在侵袭性肺曲霉病小鼠模型中,毒力没有减弱。我们的工作提供了(i)烟曲霉对过量Cu的全基因组转录反应的详细视图,(ii)鉴定AceA依赖性转录组,以及(iii)分析三种Cu伴侣cox17,atxA和ccsA的作用。