DRUG RESISTANCE IN THE PARASITE TRICHOMONAS VAGINALIS

阴道毛滴虫寄生虫的耐药性

• 批准号: 2065688
• 负责人: Patricia Jean Johnson
• 金额: $ 15.93万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1995-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2065688
• 关键词: DNA binding protein; DNA footprinting; Trichomonas vaginalis; autoradiography; densitometry; drug metabolism; drug resistance; enzyme mechanism; ferredoxin; gene expression; genetic mapping; genetic regulatory element; genetic strain; genetic transcription; messenger RNA; metronidazole; microorganism disease chemotherapy; nucleic acid hybridization; nucleic acid sequence; polymerase chain reaction; spectrometry; transcription factor; western blottings

The objective of this research is to gain an understanding of the mechanism(s) underlying drug resistance in the human parasite, Trichomonas vaginalis. Strains of T. vaginalis that are resistant to metronidazole, the only drug available in the U.S. for treatment, arise at a low frequency. Our preliminary studies show that four clinical isolates, refractory to treatment with metronidazole, have decreased intracellular levels of ferredoxin and its mRNA. Ferredoxin is a hydrogenosomal protein which is required to reduce metronidazole to its cytotoxic form. To our knowledge, this is the first demonstration of drug resistance arising due to the inability of the cell to chemically modify a drug to its active form. Additionally, we have shown that ferredoxin gene transcription is reduced in two of these resistant isolates. This indicates that regulation of gene expression is the basis of resistance. The specific aims of the proposed studies are: 1) to examine the levels of ferredoxin, as well as other hydrogenosomal proteins which are involved in drug activation, in additional sensitive and resistant lines. Resistant cell lines which have decreased intracellular levels of ferredoxin will be examined to determine if ferredoxin mRNA and/or gene transcription is altered. 2)to examine the 5' and 3' sequences flanking the ferredoxin gene in resistant and sensitive strains for differences which might account for altered transcription of the gene in resistant lines. DNA sequence motifs, and the proteins which bind to such putative transcriptional regulatory elements, will be studied. In addition to examining the mechanism of drug resistance, these studies provide a framework for exploring gene expression in this primitive eukaryote. Thus, the proposed investigation addresses both medically and fundamentally important aspects of the biology of this human pathogen. A better knowledge of the mechanisms underlying resistance will be critical for designing effective treatment regimens for cases refractory to treatment. In addition to treating trichomoniasis, metronidazole is commonly used in treatment of infections caused by other anaerobic organisms, such as Entamoeba, Giardia, Bacteroides, and Clostridium. Isolates of these organisms which are relatively resistant to the drug have been reported, but virtually nothing is known regarding the mechanism of resistance. Thus our studies on metronidazole resistance in T. vaginalis may possibly shed light on the basis of resistance in a number of pathogenic bacteria and protozoa.

这项研究的目的是为了了解 人类寄生虫耐药性的机制， 阴道毛滴虫。 具有抗性的阴道毛滴虫菌株 甲硝唑是美国唯一可用于治疗的药物 以低频。 我们的初步研究表明，四种临床 对甲硝唑治疗无效的分离株已减少 铁氧还蛋白及其 mRNA 的细胞内水平。 铁氧还蛋白是一种 将甲硝唑还原为其所需的氢糖体蛋白 细胞毒性形式。 据我们所知，这是首次演示 由于细胞不能进行化学反应而产生耐药性 将药物修改为其活性形式。 此外，我们还证明了 铁氧还蛋白基因转录在其中两种耐药细胞中减少 隔离。 这表明基因表达调控是基础 的阻力。 拟议研究的具体目标是：1） 检查铁氧还蛋白以及其他氢酶体的水平 参与药物激活的蛋白质，在额外的敏感 和抵抗线。 耐药细胞系减少 将检查铁氧还蛋白的细胞内水平以确定是否 铁氧还蛋白 mRNA 和/或基因转录发生改变。 2）检查5' 和 3' 序列位于抗性和敏感的铁氧还蛋白基因侧翼 菌株的差异可能导致转录改变 抗性品系中的基因。 DNA 序列基序和蛋白质 与这种假定的转录调控元件结合，将是 研究过。 除了研究耐药机制之外， 这些研究为探索基因表达提供了一个框架 原始真核生物。 因此，拟议的调查涉及 该生物学的医学和基本重要方面 人类病原体。 更好地了解底层机制 耐药性对于设计有效的治疗方案至关重要 对于治疗难治的病例。 除了治疗 滴虫病，甲硝唑常用于治疗感染 由其他厌氧生物引起，如内阿米巴、贾第虫、 拟杆菌属和梭菌属。 这些生物体的分离物是 据报道对该药物相对耐药，但实际上 关于耐药机制尚不清楚。 因此我们的学习 阴道毛滴虫甲硝唑耐药性的研究可能有助于揭示 是许多病原菌和原生动物抵抗力的基础。