Cha Hyunjin, Won Doyeon, Kang Seun, Kim Eui-Seong, Lee Kyung-Ah, Lee Won-Jae, Lee Kyung-Tae, Bahn Yong-Sun
Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
Korea Zoonosis Research Institute, Jeonbuk National University, Iksan, Jeonbuk, Republic of Korea.
PLoS Pathog. 2025 Jul 28;21(7):e1013363. doi: 10.1371/journal.ppat.1013363. eCollection 2025 Jul.
Candida auris, an emerging fungal pathogen characterized by its multidrug resistance and high mortality rates, poses a significant public health challenge. Despite its importance, the signaling pathways governing virulence and antifungal resistance in C. auris remain poorly understood. This study investigates the calcineurin pathway in C. auris, critical for virulence and antifungal resistance in other fungal pathogens. Calcineurin, a calcium/calmodulin-dependent protein phosphatase, comprises a catalytic subunit (Cna1) and a regulatory subunit (Cnb1) in C. auris. Our findings reveal that deletion of CNA1 or CNB1 disrupts extreme thermotolerance and cell membrane and wall integrity, leading to increased susceptibility to azoles and echinocandins. Moreover, we identified a downstream transcription factor, Crz1, which plays a central role in this pathway in other fungal species. Deletion of CRZ1 resulted in thermotolerance and membrane integrity defects comparable to those of cna1Δ and cnb1Δ mutants, along with increased azole susceptibility. Supporting it, fluconazole treatment induced Crz1 nuclear translocation in a Cna1-dependent manner. However, unlike cna1Δ and cnb1Δ mutants, the crz1Δ mutant displayed increased resistance to echinocandins, suggesting the opposing roles for Crz1 in regulating cell wall integrity. Nevertheless, echinocandins also promoted Crz1 nuclear translocation via Cna1, underscoring the complex regulatory mechanisms at play. Cna1 was found to be required for virulence in both the Drosophila systemic infection model and the murine skin infection model. However, in a systemic murine infection model, both calcineurin and Crz1 appeared dispensable for C. auris virulence. Our findings highlight that the evolutionarily conserved calcineurin pathway employs distinct regulatory mechanisms to perform divergent roles in regulating extreme thermotolerance, cell wall and membrane integrity, antifungal drug resistance, and virulence in C. auris.
耳念珠菌是一种新出现的真菌病原体，具有多重耐药性和高死亡率，对公共卫生构成重大挑战。尽管其具有重要性，但调控耳念珠菌毒力和抗真菌耐药性的信号通路仍知之甚少。本研究调查了耳念珠菌中的钙调神经磷酸酶途径，该途径对其他真菌病原体的毒力和抗真菌耐药性至关重要。钙调神经磷酸酶是一种钙/钙调蛋白依赖性蛋白磷酸酶，在耳念珠菌中由催化亚基（Cna1）和调节亚基（Cnb1）组成。我们的研究结果表明，CNA1或CNB1的缺失会破坏极端耐热性以及细胞膜和细胞壁的完整性，导致对唑类和棘白菌素的敏感性增加。此外，我们鉴定出一种下游转录因子Crz1，它在其他真菌物种的该途径中起核心作用。CRZ1的缺失导致耐热性和膜完整性缺陷，与cna1Δ和cnb1Δ突变体相当，同时唑类敏感性增加。支持这一点的是，氟康唑处理以Cna1依赖性方式诱导Crz1核转位。然而，与cna1Δ和cnb1Δ突变体不同，crz1Δ突变体对棘白菌素的抗性增加，表明Crz1在调节细胞壁完整性中具有相反的作用。尽管如此，棘白菌素也通过Cna1促进Crz1核转位，突出了其中发挥作用的复杂调控机制。在果蝇全身感染模型和小鼠皮肤感染模型中，发现Cna1是毒力所必需的。然而，在系统性小鼠感染模型中，钙调神经磷酸酶和Crz1似乎对耳念珠菌的毒力都是可有可无的。我们的研究结果强调，进化上保守的钙调神经磷酸酶途径采用不同的调控机制，在调节耳念珠菌的极端耐热性、细胞壁和膜完整性以及抗真菌药物耐药性和毒力方面发挥不同的作用。
