Genetic analysis of Hsp90 function in Cryptococcus neoformans highlights key roles in stress tolerance and virulence
Genetic analysis of Hsp90 function in Cryptococcus neoformans highlights key roles in stress tolerance and virulence
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DOI：
10.1093/genetics/iyab164
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发表时间：
2021-10-09
期刊：
影响因子：
3.3
通讯作者：
Cowen, Leah E.
中科院分区：
文献类型：
--
作者：
Fu, Ci;Beattie, Sarah R.;Cowen, Leah E.
人类机会性真菌病原体新生隐球菌对全球健康有巨大影响，每年导致181,000人死亡。目前的治疗选择有限，而且耐药性的频繁发展加剧了管理侵袭性隐球菌感染的挑战。在不同的真菌病原体中，基本的分子伴侣Hsp90控制真菌的存活、耐药性和毒力。因此，靶向这种伴侣蛋白已成为对抗真菌感染的一种很有前途的方法。然而，由于缺乏基因特征，Hsp90在支持新生葡萄球菌发病中的作用在很大程度上仍然难以捉摸。为了帮助剖析HSP90在新生葡萄球菌中的功能，我们构建了一个条件表达菌株，其中HSP90受铜抑制启动子CTR4-2的控制。在培养基中添加铜会耗尽该菌株的Hsp90转录本和蛋白水平，导致真菌在宿主温度下的生长受阻；对包括唑类抗真菌药物在内的应激源的敏感性增加；新生隐孢子菌的形态发生改变；黑色素的产生受到损害。最后，利用铜浓度在不同小鼠组织中差异很大的事实，我们证明了CTR4-2P-HSP90突变体的毒力减弱，特别是在隐球菌感染的吸入性模型中。在这个小鼠模型中，在入侵和建立感染过程中，病原体暴露在肺中相对较高的铜浓度中，而不是血液中。总体而言，这项工作建立了一个易于处理的遗传系统来研究Hsp90在支持新生葡萄球菌致病性中的作用，并提供了以Hsp90为靶点作为控制隐球菌感染的策略的原则证据。
The opportunistic human fungal pathogen Cryptococcus neoformans has tremendous impact on global health, causing 181,000 deaths annually. Current treatment options are limited, and the frequent development of drug resistance exacerbates the challenge of managing invasive cryptococcal infections. In diverse fungal pathogens, the essential molecular chaperone Hsp90 governs fungal survival, drug resistance, and virulence. Therefore, targeting this chaperone has emerged as a promising approach to combat fungal infections. However, the role of Hsp90 in supporting C. neoformans pathogenesis remains largely elusive due to a lack of genetic characterization. To help dissect the functions of Hsp90 in C. neoformans, we generated a conditional expression strain in which HSP90 is under control of the copper-repressible promoter CTR4-2. Addition of copper to culture medium depleted Hsp90 transcript and protein levels in this strain, resulting in compromised fungal growth at host temperature; increased sensitivity to stressors, including the azole class of antifungals; altered C. neoformans morphology; and impaired melanin production. Finally, leveraging the fact that copper concentrations vary widely in different mouse tissues, we demonstrated attenuated virulence for the CTR4-2p-HSP90 mutant specifically in an inhalation model of Cryptococcus infection. During invasion and establishment of infection in this mouse model, the pathogen is exposed to the relatively high copper concentrations found in the lung as compared to blood. Overall, this work generates a tractable genetic system to study the role of Hsp90 in supporting the pathogenicity of C. neoformans and provides proof-of-principle that targeting Hsp90 holds great promise as a strategy to control cryptococcal infection.