新型抑白念珠菌化合物CHR3的活性评价及 铁代谢相关机制初探

Activity Evaluation and Iron-Metabolism-Related Mechanistic Exploration of CHR3 as a Novel Anti-Candida albicans Compound

摘要: 目的：筛选新型抑白念珠菌化合物，并进行活性评价及分子机制探究。方法：以白念珠菌标准株ATCC MYA-2876 (SC5314)为筛选菌株，高通量筛选实验室已有化合物库获得潜在抑菌化合物；微量肉汤稀释法用于检测候选化合物的最小抑菌浓度(Minimum Inhibitory Concentration, MIC)；抑菌生长曲线来评价候选化合物对白念珠菌的浓度依赖作用；结合转录组分析和实时荧光定量PCR技术分析候选化合物处理后白念珠菌毒力相关基因及铁代谢相关基因的表达变化。结果：通过高通量筛选获得候选化合物 CHR3，化学分子式比对后确定该化合物是青灰霉素A。CHR3对SC5314的MIC为2 μg/mL，并可浓度依赖性抑制白念珠菌增殖。转录组分析显示，CHR3处理后白念珠菌基因表达谱发生明显改变，差异表达基因涉及代谢、遗传信息加工及细胞组分等相关生物过程。对这些差异基因进一步分析发现，ALS3、ECE1、EFG1、HGC1和HWP1等毒力相关基因表达下调，实时荧光定量PCR检测结果与转录组数据下调趋势一致。FTR2、CFL5和FRE30等铁摄取或铁还原相关基因表达降低。结论：CHR3是一种新型高活性抑白念珠菌的青灰霉素A类候选化合物，其作用可能与毒力基因下调及铁代谢相关通路扰动有关。本研究为CHR3后续靶点确证、结构优化及抗白念珠菌先导化合物开发提供了实验依据。

Abstract: Objective: To screen small-molecule compounds with inhibitory activity against Candida albicans and preliminarily investigate their potential antifungal mechanism. Methods: The C. albicans reference strain ATCC MYA-2876 (SC5314) was used for high-throughput screening of an in-house compound library. The minimum inhibitory concentration of the candidate compound was determined by broth microdilution. Growth inhibition curves were used to evaluate the concentration-dependent antifungal effects of candidate compounds against C. albicans. Transcriptome sequencing and quantitative real-time PCR were performed to analyse changes in virulence-related and iron-metabolism-related genes after compound treatment. Results: CHR3 was identified as an active candidate compound and confirmed by structural comparison as caerulomycin A. CHR3 inhibited SC5314 with a minimum inhibitory concentration of 2 μg/mL and suppressed C. albicans growth in a concentration-dependent manner. Transcriptome analysis showed marked transcriptional remodelling after CHR3 treatment, with differentially expressed genes enriched in metabolic processes, genetic information processing and cellular-component-related pathways. Virulence-associated genes including ALS3, ECE1, EFG1, HGC1 and HWP1 were downregulated, and iron uptake or ferric reductase-related genes including FTR2, CFL5 and FRE30 were also decreased. Quantitative real-time PCR confirmed the expression trends observed in transcriptome sequencing. Conclusion: CHR3 is a caerulomycin A-related candidate compound with potent inhibitory activity against C. albicans. Its antifungal effect may be associated with suppression of virulence-related genes and disruption of iron-metabolism-related pathways. These findings provide experimental evidence for further target validation, structural optimization and lead development of CHR3 against C. albicans.