Thapa Roshan, Kayejo Victor, Hube Bernhard, Naglik Julian R, Keyel Peter A
Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409.
Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute (HKI), Jena, Germany.
bioRxiv. 2025 May 13:2025.05.09.653080. doi: 10.1101/2025.05.09.653080.
The common fungal pathogen, , relies on the pore-forming toxin candidalysin to damage host cells. Cells resist other pore-forming toxins by Ca dependent microvesicle shedding and annexins (cholesterol-dependent cytolysins, CDCs), or annexins and patch repair (aerolysin). However, it is unclear which Ca dependent repair mechanism(s) resists candidalysin. Here, we determined the involvement of different Ca dependent repair mechanisms to candidalysin and compared responses to CDCs and aerolysin using flow cytometry and high-resolution microscopy. We report that candidalysin triggered Ca-dependent repair, but patch repair and ceramide failed to provide significant protection. MEK-dependent repair and annexins A1, A2 and A6 contributed partially to repairing damage caused by candidalysin. However, annexin translocation after candidalysin challenge was delayed compared to CDCs or aerolysin challenge. Surprisingly, extracellular Cl improved cell survival after candidalysin challenge, but not after challenge with a CDC or aerolysin. Finally, we found that candidalysin is removed via extracellular vesicle shedding. These findings reveal that Ca dependent microvesicle shedding protects cells from candidalysin and can be engaged by multiple molecular mechanisms during membrane repair.
常见的真菌病原体——白色念珠菌，依靠成孔毒素念珠菌溶素来损伤宿主细胞。细胞通过钙依赖的微囊泡脱落和膜联蛋白（胆固醇依赖细胞溶素，CDCs），或膜联蛋白和斑块修复（气单胞菌溶素）来抵抗其他成孔毒素。然而，尚不清楚哪种钙依赖的修复机制能抵抗念珠菌溶素。在此，我们确定了不同钙依赖修复机制对念珠菌溶素的作用，并使用流式细胞术和高分辨率显微镜比较了对CDCs和气单胞菌溶素的反应。我们报告称，念珠菌溶素触发了钙依赖的修复，但斑块修复和神经酰胺未能提供显著保护。丝裂原活化蛋白激酶（MEK）依赖的修复以及膜联蛋白A1、A2和A6对修复念珠菌溶素造成的损伤有部分作用。然而，与CDCs或气单胞菌溶素刺激相比，念珠菌溶素刺激后膜联蛋白的易位延迟。令人惊讶的是，细胞外氯离子可提高念珠菌溶素刺激后的细胞存活率，但对CDCs或气单胞菌溶素刺激后的细胞存活率无此作用。最后，我们发现念珠菌溶素可通过细胞外囊泡脱落被清除。这些发现表明，钙依赖的微囊泡脱落可保护细胞免受念珠菌溶素的侵害，并且在膜修复过程中可通过多种分子机制发挥作用。
