Clinical and Experimental Medicine PhD Program, University of Modena and Reggio Emilia, Modena, Italy.
Department of Surgical, Medical, Dental and Morphological Sciences with Interest in Transplant, Oncological and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy.
PLoS One. 2024 May 20;19(5):e0303449. doi: 10.1371/journal.pone.0303449. eCollection 2024.
Candida albicans (C. albicans) can behave as a commensal yeast colonizing the vaginal mucosa, and in this condition is tolerated by the epithelium. When the epithelial tolerance breaks down, due to C. albicans overgrowth and hyphae formation, the generated inflammatory response and cell damage lead to vulvovaginal candidiasis (VVC) symptoms. Here, we focused on the induction of mitochondrial reactive oxygen species (mtROS) in vaginal epithelial cells after C. albicans infection and the involvement of fungal burden, morphogenesis and candidalysin (CL) production in such induction. Bioluminescent (BLI) C. albicans, C. albicans PCA-2 and C. albicans 529L strains were employed in an in vitro infection model including reconstituted vaginal epithelium cells (RVE), produced starting from A-431 cell line. The production of mtROS was kinetically measured by using MitoSOX™ Red probe. The potency of C. albicans to induced cell damage to RVE and C. albicans proliferation have also been evaluated. C. albicans induces a rapid mtROS release from vaginal epithelial cells, in parallel with an increase of the fungal load and hyphal formation. Under the same experimental conditions, the 529L C. albicans strain, known to be defective in CL production, induced a minor mtROS release showing the key role of CL in causing epithelial mithocondrial activation. C. albicans PCA-2, unable to form hyphae, induced comparable but slower mtROS production as compared to BLI C. albicans yeasts. By reducing mtROS through a ROS scavenger, an increased fungal burden was observed during RVE infection but not in fungal cultures grown on abiotic surface. Collectively, we conclude that CL, more than fungal load and hyphae formation, seems to play a key role in the rapid activation of mtROS by epithelial cells and in the induction of cell-damage and that mtROS are key elements in the vaginal epithelial cells response to C. albicans.
白色念珠菌（C. albicans）可以作为共生酵母定植于阴道黏膜，并在此条件下被上皮组织耐受。当上皮组织耐受被打破时，由于白色念珠菌过度生长和菌丝形成，所产生的炎症反应和细胞损伤会导致外阴阴道念珠菌病（VVC）症状。在这里，我们专注于白色念珠菌感染后阴道上皮细胞中线粒体活性氧（mtROS）的诱导，以及真菌负荷、形态发生和念珠菌溶素（CL）产生在这种诱导中的作用。我们采用生物发光（BLI）白色念珠菌、白色念珠菌 PCA-2 和白色念珠菌 529L 菌株，在包括从 A-431 细胞系产生的重建阴道上皮细胞（RVE）的体外感染模型中进行实验。通过使用 MitoSOX™ Red 探针来测量 mtROS 的产生动力学。还评估了白色念珠菌对 RVE 细胞损伤的能力和白色念珠菌的增殖能力。白色念珠菌诱导阴道上皮细胞快速释放 mtROS，同时真菌负荷增加和菌丝形成。在相同的实验条件下，已知在 CL 产生方面存在缺陷的 529L 白色念珠菌菌株诱导的 mtROS 释放较少，表明 CL 在引起上皮细胞线粒体激活方面起着关键作用。不能形成菌丝的白色念珠菌 PCA-2 与 BLI 白色念珠菌酵母相比，诱导的 mtROS 产生相似但较慢。通过清除 ROS 来减少 mtROS，我们观察到在 RVE 感染期间真菌负荷增加，但在非生物表面上生长的真菌培养物中没有增加。总的来说，我们得出结论，CL 似乎比真菌负荷和菌丝形成更能发挥关键作用，导致上皮细胞中 mtROS 的快速激活，并诱导细胞损伤，而 mtROS 是阴道上皮细胞对白色念珠菌反应的关键因素。
