Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba, Spain.
mSphere. 2024 Jun 25;9(6):e0025324. doi: 10.1128/msphere.00253-24. Epub 2024 May 30.
is the leading cause of severe mold infections in immunocompromised patients. This common fungus possesses innate attributes that allow it to evade the immune system, including its ability to survive the high copper (Cu) levels in phagosomes. Our previous work has revealed that under high Cu levels, the transcription factor AceA is activated, inducing the expression of the copper exporter CrpA to expel excess Cu. To identify additional elements in Cu resistance, we evolved wild-type and mutant Δ or Δ strains under increasing Cu concentrations. Sequencing of the resultant resistant strains identified both shared and unique evolutionary pathways to resistance. Reintroduction of three of the most common mutations in genes encoding Pma1 (plasma membrane H-ATPase), Gcs1 (glutamate cysteine-ligase), and Cpa1 (carbamoyl-phosphate synthetase), alone and in combination, into wild-type confirmed their additive role in conferring Cu resistance. Detailed analysis indicated that the mutation L424I preserves Pma1 H-ATPase activity under high Cu concentrations and that the mutation A37V confers a survival advantage to conidia in the presence of Cu. Interestingly, simultaneous mutations of all three genes did not alter virulence in infected mice. Our work has identified novel Cu-resistance pathways and provides an evolutionary approach for dissecting the molecular basis of adaptation to diverse environmental challenges.IMPORTANCE is the most common mold infecting patients with weakened immunity. Infection is caused by the inhalation of mold spores into the lungs and is often fatal. In healthy individuals, spores are engulfed by lung immune cells and destroyed by a combination of enzymes, oxidants, and high levels of copper. However, the mold can protect itself by pumping out excess copper with specific transporters. Here, we evolved under high copper levels and identified new genetic mutations that help it resist the toxic effects of copper. We studied how these mutations affect the mold's ability to resist copper and how they impact its ability to cause disease. This is the first such study in a pathogenic mold, and it gives us a better understanding of how it manages to bypass our body's defenses during an infection.
是免疫功能低下患者严重霉菌感染的主要原因。这种常见的真菌具有先天属性，可以逃避免疫系统，包括其在吞噬体中存活高铜 (Cu) 水平的能力。我们之前的工作表明，在高 Cu 水平下，转录因子 AceA 被激活，诱导铜输出蛋白 CrpA 的表达以排出多余的 Cu。为了确定铜抗性的其他因素，我们在不断增加的 Cu 浓度下对野生型和突变型 Δ或Δ菌株进行了进化。对产生的抗性菌株进行测序，确定了对铜抗性的共同和独特的进化途径。将编码 Pma1（质膜 H+-ATP 酶）、Gcs1（谷氨酸半胱氨酸连接酶）和 Cpa1（氨基甲酰磷酸合成酶）的基因中的三个最常见突变之一的三种突变单独和组合重新引入野生型中，证实了它们在赋予铜抗性方面的累加作用。详细分析表明，L424I 突变在高 Cu 浓度下保留了 Pma1 H+-ATP 酶的活性，而 A37V 突变使分生孢子在 Cu 存在下具有生存优势。有趣的是，同时突变所有三个基因不会改变感染小鼠的毒力。我们的工作确定了新的铜抗性途径，并为剖析适应不同环境挑战的分子基础提供了一种进化方法。
重要的是，最常见的霉菌感染免疫力较弱的患者。感染是由吸入肺部的霉菌孢子引起的，通常是致命的。在健康个体中，孢子被肺部免疫细胞吞噬，并通过酶、氧化剂和高浓度铜的组合破坏。然而，霉菌可以通过使用特定的转运蛋白泵出多余的铜来保护自己。在这里，我们在高铜水平下进化了，并确定了新的基因突变，这些突变有助于它抵抗铜的毒性作用。我们研究了这些突变如何影响霉菌抵抗铜的能力以及它们如何影响其致病能力。这是在致病性霉菌中进行的第一项此类研究，它使我们更好地了解它在感染期间如何设法绕过我们身体的防御。
