Department of Microbiology and Immunology, Witebsky Center for Microbial Pathogenesis and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, New York, USA.
Department of Biology, Niagara University, Niagara, New York, USA.
mBio. 2021 Jan 12;12(1):e03225-20. doi: 10.1128/mBio.03225-20.
The human fungal pathogen is intrinsically resistant to the echinocandin antifungal drug caspofungin, which targets the β-1,3-glucan synthase encoded by Echinocandins have been on the market for 20 years, yet they are the newest class of antifungal drugs. Analysis of a Δ mutant, lacking the pumilio/FBF RNA binding protein family member Puf4, revealed exacerbated caspofungin resistance. In contrast, overexpression of resulted in caspofungin sensitivity. The mRNA contains three Puf4-binding elements (PBEs) in its 5' untranslated region. Puf4 binds with specificity to this region of The mRNA was destabilized in the Δ mutant, and the abundance of the mRNA was reduced compared to wild type, suggesting that Puf4 is a positive regulator of mRNA stability. In addition to , the abundance of additional cell wall biosynthesis genes, including chitin synthases (, , and ) and deacetylases (, , and ) as well as a β-1,6-glucan synthase gene (), was regulated by Puf4. The use of fluorescent dyes to quantify cell wall components revealed that the Δ mutant had increased chitin content, suggesting a cell wall composition that is less reliant on β-1,3-glucan. Overall, our findings suggest a mechanism by which caspofungin resistance, and more broadly, cell wall biogenesis, is regulated post-transcriptionally by Puf4. is an environmental fungus that causes pulmonary and central nervous system infections. It is also responsible for 15% of AIDS-related deaths. A significant contributor to the high morbidity and mortality statistics is the lack of safe and effective antifungal therapies, especially in resource-poor settings. Yet, antifungal drug development has stalled in the pharmaceutical industry. Therefore, it is essential to understand the mechanism by which is resistant to caspofungin to design adjunctive therapies to potentiate the drug's activity toward this important pathogen.
人源致病性真菌对棘白菌素类抗真菌药物卡泊芬净具有固有耐药性，而棘白菌素类药物的靶标是由 Echinocandins 编码的β-1,3-葡聚糖合酶。棘白菌素类药物已经上市 20 年，是最新的一类抗真菌药物。对缺乏 pumilio/FBF RNA 结合蛋白家族成员 Puf4 的Δ突变体进行分析，结果显示其对卡泊芬净的耐药性加剧。相比之下，过表达 Puf4 则导致卡泊芬净敏感性增加。 的 mRNA 在 5'非翻译区含有三个 Puf4 结合元件（PBE）。Puf4 特异性结合到 的这一区域。在Δ突变体中，mRNA 不稳定，与野生型相比， 的 mRNA 丰度降低，表明 Puf4 是 的 mRNA 稳定性的正调控因子。除了 ，细胞壁生物合成基因（包括几丁质合酶（、和）和去乙酰酶（、和）以及β-1,6-葡聚糖合酶基因（））的丰度也受到 Puf4 的调节。使用荧光染料定量细胞壁成分表明，Δ突变体的几丁质含量增加，表明细胞壁组成对β-1,3-葡聚糖的依赖性降低。总的来说，我们的研究结果表明，Puf4 通过转录后调控机制调节卡泊芬净耐药性，更广泛地说，调节细胞壁生物合成。是一种环境真菌，可引起肺部和中枢神经系统感染。它也是艾滋病相关死亡的 15%的原因。发病率和死亡率高的一个重要原因是缺乏安全有效的抗真菌治疗方法，特别是在资源匮乏的环境中。然而，抗真菌药物的开发在制药行业已经停滞不前。因此，了解 对卡泊芬净耐药的机制对于设计辅助治疗方法以增强该药物对这一重要病原体的活性至关重要。
