The ability to undergo morphological changes during adaptation to distinct environments is exploited by Candida albicans and has a direct impact on virulence. In this study, we investigated the influence of fungal extracellular vesicles (EVs) during yeast growth, biofilm formation, and morphogenesis in C. albicans. Addition of C. albicans EVs (Ca EVs) to the culture medium positively affected yeast growth. Using crystal violet staining and scanning electron microscopy (SEM), we demonstrated that Ca EVs inhibited biofilm formation by C. albicans in vitro. By time-lapse microscopy and SEM, we showed that Ca EV-treatment stops filamentation promoting pseudohyphae formation with multiple sites for yeast budding. The ability of Ca EVs to regulate dimorphism was further compared to EVs isolated from different C. albicans strains, Saccharomyces cerevisiae, and Histoplasma capsulatum. Ca EVs from distinct strains robustly inhibited yeast-to-hyphae differentiation with morphological changes occurring in less than 4 hours. A minor inhibitory effect was promoted by EVs from S. cerevisiae and H. capsulatum only after 24 hours of incubation. The inhibitory effect of Ca EVs was promoted by a combination of lipid compounds identified by gas chromatography-tandem mass spectrometry analysis as sesquiterpenes, diterpenes, and fatty acids. Remarkably, Ca EVs were also able to reverse filamentation, transforming hyphal growth to yeast forms. Transcriptomic analysis demonstrated that treatment with Ca EVs modified the expression of more than 300 genes. The most effectively upregulated pathways were related to DNA metabolism. The downregulated genes were mostly associated with extracellular and adhesion proteins. Finally, yeast cells treated with Ca EVs for 24 hours lost their agar invasive ability and were avirulent when inoculated in Galleria mellonella larvae. In summary, our results indicate that fungal EVs can profoundly modify C. albicans growth and regulate yeast-to-hypha differentiation inhibiting biofilm formation and virulence.

中文翻译：

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细胞外囊泡调节白色念珠菌的酵母生长，生物膜形成和酵母菌到菌丝的分化

白色念珠菌具有在适应不同环境的过程中经历形态变化的能力，并且对毒力具有直接影响。在这项研究中，我们调查了白色念珠菌在酵母生长，生物膜形成和形态发生过程中真菌胞外囊泡（EVs）的影响。向培养基中添加白色念珠菌EV（Ca EV）会积极影响酵母的生长。使用结晶紫染色和扫描电子显微镜（SEM），我们证明了Ca EVs抑制了白色念珠菌的生物膜形成。体外。通过延时显微镜和SEM，我们发现Ca EV处理停止了丝化，促进了假丝菌丝的形成，并带有多个发芽的位点。与从不同的白色念珠菌菌株，酿酒酵母和荚膜组织胞浆菌分离出的电动汽车相比，Ca电动汽车调节双态性的能力进一步得到了比较。来自不同菌株的Ca EV强烈抑制了酵母到菌丝的分化，并在不到4小时内发生了形态变化。A小调抑制作用通过从电动汽车促进酿酒酵母和荚膜组织胞浆菌仅在孵育24小时后。Ca EVs的抑制作用通过气相色谱-串联质谱分析鉴定为倍半萜，二萜和脂肪酸的脂质化合物的组合得到增强。值得注意的是，Ca EV也能够逆转丝状化，将菌丝生长转化为酵母形式。转录组分析表明，用Ca EV进行的处理修饰了300多个基因的表达。最有效的上调途径与DNA代谢有关。下调的基因主要与细胞外和粘附蛋白有关。最后，用Ca EV进行24小时处理的酵母细胞失去了琼脂侵袭能力，并且接种在梅勒耶尔广场（Galleria mellonella）中时无毒。幼虫。总而言之，我们的结果表明真菌电动汽车可以深刻地改变白色念珠菌的生长并调节酵母菌丝向菌丝的分化，从而抑制生物膜的形成和毒力。