Amorim-Vaz Sara, Delarze Eric, Ischer Françoise, Sanglard Dominique, Coste Alix T
Institute of Microbiology, University of Lausanne and University Hospital of Lausanne Lausanne, Switzerland.
Front Microbiol. 2015 May 5;6:367. doi: 10.3389/fmicb.2015.00367. eCollection 2015.
The aim of the present study was to identify Candida albicans transcription factors (TFs) involved in virulence. Although mice are considered the gold-standard model to study fungal virulence, mini-host infection models have been increasingly used. Here, barcoded TF mutants were first screened in mice by pools of strains and fungal burdens (FBs) quantified in kidneys. Mutants of unannotated genes which generated a kidney FB significantly different from that of wild-type were selected and individually examined in Galleria mellonella. In addition, mutants that could not be detected in mice were also tested in G. mellonella. Only 25% of these mutants displayed matching phenotypes in both hosts, highlighting a significant discrepancy between the two models. To address the basis of this difference (pool or host effects), a set of 19 mutants tested in G. mellonella were also injected individually into mice. Matching FB phenotypes were observed in 50% of the cases, highlighting the bias due to host effects. In contrast, 33.4% concordance was observed between pool and single strain infections in mice, thereby highlighting the bias introduced by the "pool effect." After filtering the results obtained from the two infection models, mutants for MBF1 and ZCF6 were selected. Independent marker-free mutants were subsequently tested in both hosts to validate previous results. The MBF1 mutant showed impaired infection in both models, while the ZCF6 mutant was only significant in mice infections. The two mutants showed no obvious in vitro phenotypes compared with the wild-type, indicating that these genes might be specifically involved in in vivo adapt.
本研究的目的是鉴定参与毒力的白色念珠菌转录因子（TFs）。尽管小鼠被认为是研究真菌毒力的金标准模型，但小型宿主感染模型的使用越来越多。在这里，首先通过菌株库在小鼠中筛选带条形码的TF突变体，并对肾脏中的真菌负荷（FBs）进行定量。选择产生与野生型肾脏FB有显著差异的未注释基因突变体，并在大蜡螟中单独检测。此外，在小鼠中无法检测到的突变体也在大蜡螟中进行了测试。这些突变体中只有25%在两个宿主中表现出匹配的表型，突出了两种模型之间的显著差异。为了解决这种差异的基础（混合或宿主效应），在大蜡螟中测试的一组19个突变体也被单独注射到小鼠体内。在50%的病例中观察到匹配的FB表型，突出了宿主效应导致的偏差。相比之下，在小鼠中混合感染和单菌株感染之间的一致性为33.4%，从而突出了“混合效应”引入的偏差。在筛选从两种感染模型获得的结果后，选择了MBF1和ZCF6的突变体。随后在两个宿主中测试了独立的无标记突变体，以验证先前的结果。MBF1突变体在两种模型中均显示感染受损，而ZCF6突变体仅在小鼠感染中显著。与野生型相比，这两个突变体在体外没有明显的表型，表明这些基因可能特别参与体内适应。
