Species-Specific Differences in C-5 Sterol Desaturase Function Influence the Outcome of Azole Antifungal Exposure.
Species-Specific Differences in C-5 Sterol Desaturase Function Influence the Outcome of Azole Antifungal Exposure.
复制标题
C-5 甾醇去饱和酶功能的物种特异性差异影响唑类抗真菌药物暴露的结果。
DOI：
10.1128/aac.01044-21
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发表时间：
2021
影响因子：
4.9
通讯作者：
Palmer,GlenE
中科院分区：
文献类型：
--
作者：
Luna-Tapia,Arturo;Parker,JosieE;Kelly,StevenL;Palmer,GlenE
唑类抗真菌药抑制甾醇 14α-去甲基酶 (S14DM)，导致细胞麦角甾醇的消耗和异常甾醇二醇的合成，从而破坏膜功能。在白色念珠菌中，甾醇二醇的产生是由 ERG3 编码的 C-5 甾醇去饱和酶催化的。因此，使 ERG3 失活的突变使真菌能够在唑类存在的情况下生长。本研究的目的是比较不同真菌病原体的 C-5 甾醇去饱和酶在 S14DM 抑制后产生有毒二醇的倾向，从而有助于抗真菌功效。来自白色念珠菌（CaERG3）、光滑念珠菌（CgERG3）、耳念珠菌（CaurERG3）、新型隐球菌（CnERG3）、烟曲霉（AfERG3A-C）和德雷根霉（RdERG3A/B）的ERG3同源物的编码序列在念珠菌中表达。 albicanserg3Δ/Δ突变体以方便比较分析。除一种 Erg3p 样蛋白 (AfErg3C) 外，所有其他蛋白都至少部分恢复了 C-5 甾醇去饱和酶活性，并在相应程度上挽救了 C. albicanserg3Δ/Δ 突变体的应激和菌丝生长缺陷，证实了功能等效性。就 MIC 和超 MIC 观察到的残留生长而言，每种 C-5 去饱和酶对氟康唑暴露具有显着不同的反应。在氟康唑介导的 S14DM 抑制作用下，表达每种同源物的菌株也产生不同水平的 14α-methylergosta-8,24(28)-dien-3β,6α-diol。 RdErg3A 和 AfErg3A 蛋白以低水平的甾醇二醇产生而闻名，并且未能赋予 C. albicanserg3Δ/Δ 突变体明显的唑类敏感性。这些发现表明，C-5 甾醇去饱和酶的物种特异性特性可能是内在唑类敏感性的重要决定因素。
The azole antifungals inhibit sterol 14α-demethylase (S14DM), leading to depletion of cellular ergosterol and the synthesis of an aberrant sterol diol that disrupts membrane function. In Candida albicans, sterol diol production is catalyzed by the C-5 sterol desaturase enzyme encoded byERG3. Accordingly, mutations that inactivateERG3enable the fungus to grow in the presence of the azoles. The purpose of this study was to compare the propensities of C-5 sterol desaturases from different fungal pathogens to produce the toxic diol upon S14DM inhibition and thus contribute to antifungal efficacy. The coding sequences ofERG3homologs from C. albicans (CaERG3), Candida glabrata (CgERG3), Candida auris (CaurERG3), Cryptococcus neoformans (CnERG3), Aspergillus fumigatus (AfERG3A-C) and Rhizopus delemar (RdERG3A/B) were expressed in a C. albicanserg3Δ/Δ mutant to facilitate comparative analysis. All but one of the Erg3p-like proteins (AfErg3C) at least partially restored C-5 sterol desaturase activity and to corresponding degrees rescued the stress and hyphal growth defects of the C. albicanserg3Δ/Δ mutant, confirming functional equivalence. Each C-5 desaturase enzyme conferred markedly different responses to fluconazole exposure in terms of the MIC and residual growth observed at supra-MICs. Upon fluconazole-mediated inhibition of S14DM, the strains expressing each homolog also produced various levels of 14α-methylergosta-8,24(28)-dien-3β,6α-diol. The RdErg3A and AfErg3A proteins are notable for low levels of sterol diol production and failing to confer appreciable azole sensitivity upon the C. albicanserg3Δ/Δ mutant. These findings suggest that species-specific properties of C-5 sterol desaturase may be an important determinant of intrinsic azole sensitivity.