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Chlamydial lipid acquisition and host response

衣原体脂质获取和宿主反应

基本信息

批准号：
8769621
负责人：
Elizabeth Ann Rucks
金额：
$ 44.33万
依托单位：
UNIVERSITY OF SOUTH DAKOTA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-01 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8769621
关键词：
Accounting Affect Age Antibiotics Automobile Driving Bacteria Binding Cell Wall Cell membrane Cell model Cells Centers for Disease Control and Prevention (U.S.)Cervical Chlamydia Chlamydia Infections Chlamydia trachomatis Cholesterol Co-Immunoprecipitations Data Detection Disease Progression Docking Epithelial Cells Event Family Fluorescence Fluorescent Antibody Technique Golgi Apparatus Growth HIV High Pressure Liquid Chromatography Host Defense Host Defense Mechanism Human Papillomavirus Imaging Techniques Immune response Infant Infection Infection prevention Infertility Intercept Life Style Link Lipids Mediating Medical Membrane Membrane Fusion Mothers Nutrient Organelles Organism Pathogenesis Peptide Signal Sequences Play Prevention strategy Process Production Protein Biosynthesis Proteins Recruitment Activity Recycling Research Design Risk Role SNAP receptor Sexually Transmitted Diseases Signal Pathway Signal Transduction Site Source Specificity Sphingomyelins Structural Protein Structure Techniques Testing Time Vacuole Vesicle Woman base cost cytokine design lipid transport member novel prevent protein protein interaction public health relevance receptor soluble NSF attachment protein syntaxin syntaxin 6 trafficking transmission process

项目摘要

DESCRIPTION (provided by applicant): Although chlamydial infections are treatable with antibiotics, current prevention strategies fail to reduce new infections and subsequent sequelae. Hence, there is a great need to further understand chlamydial survival mechanisms within the host to identify efficacious targets to prevent infection, increase the ease of detection or interrupt/control chlamydial growth. Paramount to chlamydial survival within the host is the organism's ability to obtain and utilize host cell-derived lipids. Within the host cell, EBs differentiate into RBs in a membrane-bound vacuole termed the chlamydial inclusion. The inclusion intercepts a subset of Golgi-derived exocytic vesicles containing sphingomyelin and cholesterol. Utilizing a polarized epithelial cell model to study directional trafficking of lipidsand proteins to the inclusion, we demonstrated that the chlamydial inclusion preferentially intercepts basolaterally targeted exocytic vesicles, suggesting that C. trachomatis specifically interact with a subset of basolateral trafficking machinery. Subsequent studies demonstrated that trans-Golgi SNARE protein syntaxin 6 colocalizes with the chlamydial inclusion in a manner that is conserved across chlamydial species, requires chlamydial protein synthesis and utilizes a eukaryotic signal sequence, YGRL. The YGRL signal sequence returns syntaxin 6 to the trans-Golgi from the plasma membrane; the requirement of this signal sequence for syntaxin 6 localization to the inclusion suggests that syntaxin 6 cycles on and off the inclusion membrane. Recently, we demonstrated that a second trans-Golgi SNARE protein, syntaxin 10 colocalizes to the chlamydial inclusion in a manner distinct from the localization of syntaxin 6. Syntaxin 10 colocalizes to the inclusion in association with Golgi structural proteins, indicating that insteadof docking vesicles to the inclusion, it may dock Golgi-structures. Based on the localization of both syntaxin 6 and syntaxin 10, we propose that these proteins may be interacting with distinct pools of proteins thereby affecting their function at the chlamydial inclusion. The driving hypothesis of this proposal is that Chlamydia recruit syntaxin 6 and 10 to traffic lipids to or fro the inclusion and the organisms themselves; as the precise composition of host lipids in chlamydial organisms is linked to the ability of Chlamydia to limit host defense during an infection. In Aim 1, we will interrogate protein-protein interactions and the trafficking dynamics f syntaxins 6 and 10 at the inclusion. For the first time, recycling events will be examined at the chlamydial inclusion membrane. In Aim 2, we will correlate the localization of specific syntaxin proteins with distinct changes in chlamydial lipid composition, and then, link the changes in chlamydial lipid composition to host response by examining the effect of lipid-altered chlamydial organisms on the activation of specific cell signaling pathways. Studies in this proposal will examine discrete mechanisms of chlamydial acquisition, using novel imaging techniques. Significantly, we will interrogate how eukaryotic lipids that are incorporated into the chlamydial cell wall impact host response to infection.

描述（由申请方提供）：尽管衣原体感染可用抗生素治疗，但目前的预防策略未能减少新发感染和后续后遗症。因此，非常需要进一步了解宿主内衣原体的存活机制，以确定有效的靶点来预防感染，增加检测的容易性或中断/控制衣原体生长。衣原体在宿主体内存活的最重要因素是生物体获得和利用宿主细胞来源的脂质的能力。在宿主细胞内，EB在被称为衣原体包涵体的膜结合液泡中分化成RB。内含物拦截高尔基体衍生的含有鞘磷脂和胆固醇的胞吐囊泡的子集。利用极化上皮细胞模型研究脂质和蛋白质向包涵体的定向运输，我们证明衣原体包涵体优先拦截基底外侧靶向的胞吐囊泡，这表明C.沙眼特异性地与一种基底外侧贩卖机制随后的研究表明，trans-Golgi SNARE蛋白syntaxin 6与衣原体包涵体共定位的方式是保守的衣原体物种，需要衣原体蛋白质的合成，并利用真核细胞的信号序列，YGRL。YGRL信号序列将突触融合蛋白6从质膜返回到trans-Golgi;突触融合蛋白6定位到包涵体的该信号序列的要求表明突触融合蛋白6在包涵体膜上循环和离开包涵体膜。最近，我们证明了第二个反式高尔基体陷阱蛋白，syntaxin 10共定位到衣原体包涵体的方式不同于本地化的syntaxin 6。Syntaxin 10与高尔基体结构蛋白共定位于包涵体，表明它可以停靠高尔基体结构，而不是对接囊泡。基于这两个syntaxin 6和syntaxin 10的本地化，我们建议，这些蛋白质可能会与不同的蛋白质池相互作用，从而影响其功能的衣原体包含。该提议的驱动假设是衣原体招募突触融合蛋白6和10来运输脂质往返于包涵体和生物体本身;因为衣原体生物体中宿主脂质的精确组成与衣原体在感染期间限制宿主防御的能力有关。在目标1中，我们将询问蛋白质-蛋白质相互作用和运输动力学的突触融合蛋白6和10的包容。这是第一次，将在衣原体包涵体膜上检查再循环事件。在目标2中，我们将相关的本地化特定的syntaxin蛋白质与衣原体脂质组成的不同变化，然后，链接的衣原体脂质组成的变化，主机响应通过检查脂质改变衣原体生物体的激活特定的细胞信号通路的影响。本研究将使用新的成像技术来研究衣原体感染的离散机制。值得注意的是，我们将询问真核脂质是如何被纳入衣原体细胞壁影响宿主对感染的反应。