A novel Approach to Target Trypanosome, Leishmania and Superbugs to the Lysosomal Compartment

这项研究的长期目标是开发一种新的治疗方法，通过提供抗病毒药物、抗生素和疫苗的替代疗法，彻底改变治疗传染病的方式。锥虫病（锥虫病）、利什曼病（利什曼病）、布鲁氏菌病（布鲁氏菌病）和结核病（分枝杆菌病）是野生物种、家畜和人类的主要传染病，目前尚无有效的治疗方法。众所周知，大多数病原体通过内吞作用侵入细胞，通过附着于现有的细胞表面受体。一旦进入细胞，病原体就会欺骗吞噬体和溶酶体，并优先在它们内部分裂。在真核细胞中，新合成的蛋白质向核内体、吞噬体和溶酶体的传递依赖于高尔基体，即对蛋白质进行分类和靶向到达这些目的地的细胞器。传递到核内体、吞噬体和溶酶体的蛋白质包括酶和激活蛋白。它们通过特殊的分选受体被引导到那里。我们发现，溶酶体激活蛋白“Prosaposin”（PSAP）中的一个区域包含一个基序，该基序与一种称为“Sortilin”的分选受体结合，并因此运输到内溶酶体腔室。在我们最近的“NSERC资助”中，我们证明了与PSAP溶酶体靶向基序相关的抗菌蛋白-防御素和Tachyplesin被递送到内体和溶酶体中。在本提案中，我们想验证以下假设：1)-Defensin-PSAP和Tachyplesin-PSAP通过Sortilin直接进入内溶酶体系统；2)Tachyplesin-PSAP在感染细胞的溶酶体腔室中具有杀锥虫和利什曼虫作用；3) -防御素- psap在感染细胞的溶酶体腔室中具有杀菌作用。因此，本研究将评估这些抗菌融合蛋白杀死吞噬体和溶酶体内的锥虫、利什曼原虫和细菌的有效性。我们的研究将允许建立一种消除内切酶/溶酶体区室病原体的新策略的概念证明。我们的研究结果将与野生、濒危、家养动物物种以及人类传染病的治疗相关，并将开辟无数的途径来研究抗致病性肽在病毒、细菌和原虫感染中的传递和作用。

The long term objective of this research is to develop a novel therapeutic approach that will revolutionize the way transmissible diseases are treated, by offering an alternative therapy to antiviral drugs, antibiotics and vaccines. Trypanosomiasis (Trypanosoma spp.), leishmaniosis (Leishmania spp.), brucellosis (Brucella spp.), and tuberculosis (Mycobacterium spp.), for which there are no effective cures or treatments are major infectious agents in wild species, domestic animals and humans. It is well known that the majority of pathogens invade the cell via endocytosis, by attaching to existing cell surface receptors. Once inside the cell, the pathogens trick the phagosomes and lysosomes and preferentially divide within them. In eukaryotic cells the delivery of newly synthesized proteins to endosomes, phagosomes and lysosomes is dependent on the Golgi apparatus, i.e., the organelle that sorts and targets proteins to these destinations. Proteins delivered to endosomes, phagosomes and lysosomes include enzymes and activator proteins. They are directed therein via special sorting receptors. We found that a region in the lysosomal activator protein “Prosaposin” (PSAP) contains a motif required for its binding to a sorting receptor called “Sortilin” and consequently for its transport to the endolysosomal compartment. During our last “NSERC Grant” we demonstrated that the antimicrobial proteins -Defensin and Tachyplesin linked to the lysosomal targeting motif of PSAP were delivered to endosomes and lysosomes. In this proposal, we would like to test the following hypotheses: 1) -Defensin-PSAP and Tachyplesin-PSAP are directed to the endolysosomal system via Sortilin; 2)Tachyplesin-PSAP has trypanocidal and leishmanocidal effects in the lysosomal compartment of infected cells; 3) -Defensin-PSAP has a bactericidal effect in the lysosomal compartment of infected cells. Thus, the present study will assess the effectiveness of these antimicrobial fusion proteins to kill trypanosomes, leishmania and bacteria within phagosomes and lysosomes. Our study will permit to establish a proof of concept of a new strategy for the elimination of pathogens in the endo/lysosomal compartment. The outcome of our research will be relevant for the treatment of infectious diseases in wild, endangered, and domestic animal species, as well as in humans and will open innumerable avenues to examine the delivery and effects of antipathogenic peptides in viral, bacterial and protozoal infections.