Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Chemistry. 2012 Jul 2;18(27):8403-13. doi: 10.1002/chem.201200482. Epub 2012 Jun 1.
Trypanosoma brucei is a parasite that causes African sleeping sickness in humans and nagana in livestock and is transmitted by the tsetse fly. There is an urgent need for the development of new drugs against African trypanosomiasis due to the lack of vaccines and effective drugs. Orlistat (also called tetrahydrolipstatin or THL) is an FDA-approved antiobesity drug targeting primarily the pancreatic and gastric lipases within the gastrointestinal tract. It shows potential activities against tumors, mycobacteria, and parasites. Herein, we report the synthesis and evaluation of an expanded set of orlistat-like compounds, some of which showed highly potent trypanocidal activities in both the bloodstream form (BSF) and the procyclic form (PCF) of T. brucei. Subsequent in situ parasite-based proteome profiling was carried out to elucidate potential cellular targets of the drug in both forms. Some newly identified targets were further validated by the labeling of recombinantly expressed enzymes in Escherichia coli lysates. Bioimaging experiments with a selected compound were carried out to study the cellular uptake of the drug in T. brucei. Results indicated that orlistat is much more efficiently taken up by the BSF than the PCF of T. brucei and has clear effects on the morphology of mitochondria, glycosomes, and the endoplasmic reticulum in both BSF and PCF cells. These results support specific effects of orlistat on these organelles and correlate well with our in situ proteome profiling. Given the economic challenges of de novo drug development for neglected diseases, we hope that our findings will stimulate further research towards the conversion of orlistat-like compounds into new trypanocidal drugs.
布氏锥虫是一种寄生虫，会导致人类的昏睡病和牲畜的那加那病，并通过采采蝇传播。由于缺乏疫苗和有效药物，迫切需要开发针对非洲锥虫病的新药。奥利司他（也称为四氢脂抑素或 THL）是一种获得 FDA 批准的减肥药，主要针对胃肠道内的胰腺和胃脂肪酶。它显示出对肿瘤、分枝杆菌和寄生虫的潜在活性。在此，我们报告了一组扩展的奥利司他类似物的合成和评估，其中一些在布氏锥虫的血液形式（BSF）和前循环形式（PCF）中均表现出高度有效的杀锥虫活性。随后进行了基于寄生虫的原位蛋白质组谱分析，以阐明该药物在两种形式中的潜在细胞靶标。一些新鉴定的靶标通过在大肠杆菌裂解物中标记重组表达的酶进一步得到验证。用选定的化合物进行生物成像实验，以研究该药物在 T. brucei 中的细胞摄取。结果表明，奥利司他在 BSF 中的摄取效率远远高于 T. brucei 的 PCF，并且对 BSF 和 PCF 细胞中线粒体、糖体和内质网的形态有明显影响。这些结果支持奥利司他对这些细胞器的特定作用，并与我们的原位蛋白质组谱分析很好地相关。鉴于新药物开发对被忽视疾病的经济挑战，我们希望我们的发现将激发进一步的研究，将奥利司他类似物转化为新的杀锥虫药物。
