MT VET COBRE PROJECT 1: HOST-PATHOGEN COMMUNICATION IN TOXOPLASMA

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。刚地弓形虫每年感染150万人，仅次于细菌病原体李斯特菌和沙门氏菌，是美国感染相关死亡的主要原因[1,2]。弓形虫对未出生的胎儿、接受化疗或器官移植的患者以及艾滋病患者都有危险[2-5]。慢殖子的发育最终导致永久性感染[6]，因此，在免疫功能低下的患者中，发病率和死亡率是显著的，其中慢殖子-速殖子转换是临床弓形虫病[5]发病机制的基础。我们已经确定，选定的三取代吡咯[11-13]会影响人成纤维细胞，使其在感染后48小时内诱导vegf株速殖子分化为慢殖子。我们的假设是，这些分子通过调节宿主细胞基因表达诱导VEG菌株速殖子发育，并且特定的宿主细胞通路提供寄生虫监测慢殖子发育时间的主要信号。我们使用DNA微阵列鉴定了80种不同的mrna，这些mrna的表达与诱导的慢殖子发育一致。对这些mrna的早期分析表明，许多mrna可以直接或间接地与宿主细胞的生长调节途径和增殖状态相关。我们已经得出结论，三取代吡咯指定的化合物1通过调节宿主细胞转录诱导寄生虫组织囊肿的发育，并且新的转录事件最终向寄生虫发出信号，以建立永久性感染。通过实验改变宿主细胞，诱导侵入的速殖子启动慢殖子的发育，为研究这一现象提供了新的实验策略。这些mrna编码的蛋白质有助于确定特定宿主环境的分子特征，这些环境或多或少有利于慢殖子分化，并可能为治疗这种感染提供一个或多个靶点。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Toxoplasma gondii infects 1.5 million human subjects annually and ranks only behind the bacterial pathogens, Listeria and Salmonella, as a leading cause of infection-related death in the US [1,2]. Toxoplasma can be dangerous to the unborn, to patients undergoing chemotherapy or organ transplant, and to people with AIDS [2-5]. Bradyzoite development is ultimately responsible for permanent infection [6], and as such, morbidity and mortality is significant in the immunocompromised where bradyzoite-tachyzoite switching underlies the pathogenesis of clinical toxoplasmosis [5]. We have determined that selected trisubstituted pyrroles [11-13], will affect a human fibroblast to induce VEG-strain tachyzoites to undergo bradyzoite differentiation within 48 h post-infection. Our hypothesis is that these molecules induce bradyzoite development in VEG strain tachyzoites by modulating host cell gene expression, and that specific host cell pathways provide the primary signal that parasites monitor to time bradyzoite development. We have used DNA microarrays to identify 80 distinct mRNAs, whose expression is coincident with induced bradyzoite development. Early analyses of these mRNAs indicate that many can be directly or indirectly associated with growth regulatory pathways and the proliferative state of the host cell. We have concluded the trisubstituted pyrrole designated Compound 1 induces parasite tissue cyst development by modulating host cell transcription, and that new transcription events ultimately signal the parasite to establish a permanent infection. The ability to experimentally alter the host cell, such that, tachyzoites that invade are induced to initiate bradyzoite development provides new experimental strategies to study this phenomenon. Proteins encoded by these mRNAs help to define the molecular features of a specific host environment that is more (or less) conducive to bradyzoite differentiation, and may provide one or more targets for the treatment of this infection.