School of Pharmacy, Naval Medical University, Shanghai, 200433, P. R. China.
91034 PLA troops, Xuancheng, 200072, P.R. China.
Med Mycol. 2022 Sep 7;60(9). doi: 10.1093/mmy/myac053.
Baicalein could inhibit the growth and biofilm formation of Candida albicans, the most common clinical fungal pathogen. However, the antifungal mechanism of baicalein has not been elucidated. In this study, isobaric tags for relative and absolute quantification (iTRAQ) was used to verify the mechanism of antifungal fluconazole and baicalein. A total of 58 common proteins were detected in cells treated with fluconazole. These proteins encompassed fluconazole-targeted sterol synthesis pathway, including Erg11p, Erg6p, Erg3p, Erg25p, Erg5p, Erg10p, and Ncp1p. Next, iTRAQ was applied to the comparison of baicalein-treated C. albicans proteins, which detected 16 common proteins. The putative NADH dehydrogenase Cpd2p and the ATP-binding cassette transporter Snq2p were the most upregulated proteins with the treatment of baicalein. Our results showed that CPD2 disruption elevated C. albicans resistance to baicalein significantly both in vitro and in vivo. Further in-depth studies revealed that CPD2 disruption reduced the activation of C. albicans metacaspase and partially restored the mitochondrial membrane potential reduction caused by the treatment of baicalein, which indicated that CPD2 was involved in the apoptosis induced by baicalein. Consistently, under the treatment of baicalein, CPD2Δ/Δ mutant produced lower reactive oxygen species that was critical in causing oxidative damage and apoptosis in C. albicans. These results indicated that baicalein could increase intracellular oxidative damage by upregulating the expression of Cpd2p so as to inhibit the growth of C. albicans, which provides new insights for investigating the antifungal target of baicalein.
白杨素可以抑制白色念珠菌（最常见的临床真菌病原体）的生长和生物膜形成。然而，白杨素的抗真菌机制尚未阐明。在这项研究中，使用同位素相对和绝对定量（iTRAQ）技术来验证抗真菌氟康唑和白杨素的作用机制。在氟康唑处理的细胞中检测到 58 种常见蛋白质。这些蛋白质涵盖了氟康唑靶向的固醇合成途径，包括 Erg11p、Erg6p、Erg3p、Erg25p、Erg5p、Erg10p 和 Ncp1p。接下来，应用 iTRAQ 比较了白杨素处理的白色念珠菌蛋白，检测到 16 种常见蛋白。假定的 NADH 脱氢酶 Cpd2p 和 ATP 结合盒转运蛋白 Snq2p 是用白杨素处理后上调最明显的蛋白质。我们的结果表明，CPD2 缺失显著提高了白色念珠菌对白杨素的体外和体内抗性。进一步的深入研究表明，CPD2 缺失减少了白色念珠菌 metacaspase 的激活，并部分恢复了由白杨素处理引起的线粒体膜电位降低，这表明 CPD2 参与了由白杨素诱导的细胞凋亡。一致地，在白杨素处理下，CPD2Δ/Δ 突变体产生的活性氧（ROS）较低，ROS 在导致白色念珠菌氧化损伤和细胞凋亡中起关键作用。这些结果表明，白杨素可以通过上调 Cpd2p 的表达增加细胞内氧化损伤，从而抑制白色念珠菌的生长，为研究白杨素的抗真菌靶标提供了新的见解。
