Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China.
Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA.
Molecules. 2019 Aug 29;24(17):3155. doi: 10.3390/molecules24173155.
Fungal infection is a leading cause of mortality in immunocompromised population; thus, it is urgent to develop new and safe antifungal agents. Different from human cells, fungi have a cell wall, which is composed mainly of polysaccharide glucan and chitin. The unique cell wall structure is an ideal target for antifungal drugs. In this research, a chemical-genetic method was used to isolate antifungal agents that target chitin synthesis in yeast cells. From a compound library, we isolated two benzothiazole compounds that showed greater toxicity to yeast mutants lacking glucan synthase Fks1 compared to wild-type yeast cells and mutants lacking chitin synthase Chs3. Both of them inhibited the activity of chitin synthase in vitro and reduced chitin level in yeast cells. Besides, these compounds showed clear synergistic antifungal effect with a glucan synthase inhibitors caspofungin. Furthermore, these compounds inhibited the growth of and opportunistic pathogen . Surprisingly, the genome-wide mass-spectrometry analysis showed decreased protein level of chitin synthases in cells treated with one of these drugs, and this decrease was not a result of downregulation of gene transcription. Therefore, we successfully identified two new antifungal agents that inhibit chitin synthesis using a chemical-genetic method.
真菌感染是免疫功能低下人群死亡的主要原因；因此，迫切需要开发新的安全的抗真菌药物。与人类细胞不同，真菌有细胞壁，主要由多糖葡聚糖和几丁质组成。独特的细胞壁结构是抗真菌药物的理想靶点。在这项研究中，我们使用化学遗传学方法分离了靶向酵母细胞中几丁质合成的抗真菌剂。从化合物库中，我们分离到两种苯并噻唑类化合物，它们对缺乏葡聚糖合酶 Fks1 的酵母突变体的毒性比对野生型酵母细胞和缺乏几丁质合酶 Chs3 的突变体更大。这两种化合物都能抑制几丁质合酶的体外活性，并降低酵母细胞中的几丁质水平。此外，这些化合物与葡聚糖合酶抑制剂卡泊芬净表现出明显的协同抗真菌作用。此外，这些化合物还能抑制 和机会性病原体 的生长。令人惊讶的是，全基因组质谱分析显示，在用其中一种药物处理的细胞中，几丁质合酶的蛋白水平降低，而这种降低不是转录下调的结果。因此，我们成功地使用化学遗传学方法鉴定了两种新的抑制几丁质合成的抗真菌药物。
