Fatty Alcohol Synthesis and Virulence in Leishmania

 描述(申请人提供)：利什曼原虫是一种原生动物寄生虫，在世界各地的热带和亚热带地区引起重要的人类疾病，因此是一个重大的公共卫生问题。乙醚类脂类是利什曼原虫细胞膜的重要成分，更重要的是，它是各种毒力因子的结构成分，如非常丰富的细胞表面脂多糖和糖基磷脂酰肌醇(GPI)锚定的蛋白酶GP63。两者在寄生虫的整个生命周期中都发挥着至关重要的作用。目前用于临床试验的米替福辛等以乙醚为基础的药物，在体内和体外抑制寄生虫的生长，并可能干扰乙醚脂质的生物合成途径。这支持了这一代谢途径可以作为进一步药物设计的靶点的想法。我们以前的研究已经证实，大型乳杆菌乙醚类脂生物合成途径的前两个酶，二羟丙酮磷酸酰基转移酶LmDAT和烷基二羟基丙酮磷酸合成酶LmADS，参与了毒力因子脂磷糖和细胞醚脂的合成，这在寄生虫的致病过程中起着至关重要的作用。我们的初步结果表明，LmFAR参与了脂肪醇的产生，而脂肪醇是合成乙醚类脂类所必需的，以及II)LmFAR对寄生虫的生长很重要。这项提议将检验中心假设，即利什曼原虫过氧体脂肪酰基辅酶A还原酶LmFAR对于乙醚脂肪代谢和毒力因子脂磷脂多糖的产生是必不可少的，从而对致病机制起关键作用。为了验证这一假设，我们建议使用两个特定的目标，结合涉及分子生物学、遗传学、生物化学和细胞生物学技术的多学科方法。在具体目标1中，我们将研究LmFAR的酶学性质及其亚细胞定位。在具体目标2中，我们将评估LmFAR在乙醚脂质生物合成、毒力和对乙醚脂质药物敏感性方面的重要性。了解LmFAR的功能对于开发预防和治疗利什曼原虫感染的新策略非常重要。此外，该项目将通过为贫困学生提供大量学习生物医学研究基础知识的机会来改善圣约翰大学的研究环境。

 DESCRIPTION (provided by applicant): Leishmania species are protozoan parasites that cause important human diseases in the tropics and subtropics worldwide and, thus, represent a major public health problem. Ether lipids are important constituents of Leishmania membranes, and more importantly, are structural components of various virulence factors, such as the very abundant cell surface lipophosphoglycan and the glycosylphosphatidylinositol(GPI)-anchored protease GP63. Both play crucial roles during the entire life cycle of the parasite. Ether lipid-based drugs such as miltefosine, currently used in clinical trials, inhibit parasite growth in vitr and in vivo, and are likely to interfere with the ether lipid biosynthetic pathway. This supports te idea that this metabolic route can be targeted for further drug design. Our previous studies have established that the first two enzymes of the ether lipid biosynthetic pathway in L. major, dihydroxyacetonephosphate acyltransferase LmDAT and alkyl dihydroxyacetonephosphate synthase LmADS, are implicated in the synthesis of the virulence factor lipophosphoglycan and cellular ether lipids, which play a crucial role in parasite pathogenesis. Our preliminary results have suggested that i) LmFAR is involved in the production of fatty alcohols which are essential for the synthesis of ether lipids, and ii) LmFAR is important for growth of the parasite. This proposal will test the central hypothesis that Leishmania peroxisomal fatty acyl-CoA reductase LmFAR is essential for ether lipid metabolism and generation of the virulence factor lipophosphoglycan, and consequently, for pathogenesis. To test this hypothesis, we propose to use two Specific Aims that combine a multidisciplinary approach that involves molecular biology, genetics, biochemistry, and cell biology techniques. In Specific Aim 1, we will investigate the enzymatic properties of LmFAR and its subcellular localization. In Specific Aim 2, we will assess the importance of LmFAR in ether lipid biosynthesis, virulence, and sensitivity to ether lipid-based drugs. Understanding the function of LmFAR is important for the development of novel strategies to prevent and treat Leishmania infections. In addition, this project will enhance the research environment at St. John's University by providing underprivileged students with numerous opportunities to learn the fundamentals of biomedical research.