Mechanisms of placental infection by food-borne pathogens

食源性病原体胎盘感染的机制

• 批准号: 8692640
• 负责人: Lakshmi Krishnan
• 金额: $ 41.21万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8692640
• 关键词: Address; Apoptosis; Birth; Caspase; Cell Communication; Cell Culture Techniques; Cell Death; Cell Death Signaling Process; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Choriocarcinoma; Cytokine Inducible SH2-Containing Protein; Development; Disease Outbreaks; Environment; Feedback; Fetus; Future; Gene Expression; Gestational Age; Growth; High Risk Woman; Human; Immune response; Immunity; In Vitro; Infection; Infection Control; Infection of amniotic sac and membranes; Inflammation; Inflammatory; Interferons; Interleukin-18; Intervention; Kinetics; Knowledge; Lead; Maps; Molecular; Molecular Target; Mothers; Mus; Outcome; Pathogenicity; Pathway interactions; Phagocytosis; Placenta; Population; Predisposition; Pregnancy; Pregnancy Complications; Pregnancy Trimesters; Pregnant Women; Proliferating; Relative (related person); Research; Resolution; Risk; Role; Salmonella; Salmonella infections; Signal Pathway; Signal Transduction; Spontaneous abortion; Testing; Tissues; Treatment Protocols; United States; Vacuole; Virulence; Virulence Factors; Virulent; Work; cell type; fetal; foodborne infection; foodborne pathogen; in vivo; inhibitor/antagonist; innovation; insight; knock-down; member; mouse model; neonatal sepsis; pathogen; pregnant; premature; therapy development; trophoblast; uptake

DESCRIPTION (provided by applicant): Pregnant women are at high risk for invasive Salmonella infection, which can cause both maternal and fetal complications. We found that Salmonella infection in pregnant mice caused rapid fetal and maternal death due to massive bacterial proliferation in placental trophoblast cells (TBCs). In vitro, Salmonella flourished in human trophoblast-derived choriocarcinoma cells. However, there is a gap in our knowledge regarding the mechanism of increased susceptibility to Salmonella infection during pregnancy. Our long-term objective is to develop strategies that can control the outcome of intracellular infections in pregnant women. The overall objective of this application is to identify the molecular mechanisms that render TBCs highly susceptible to Salmonella. Our central hypothesis is that placental TBCs are productively infected by Salmonella and provide a unique intra- cellular niche that permits uncontrolled virulent Salmonella replication due to an ineffectie immune response, resulting in placental death. Our central hypothesis will be tested by three Specific Aims which will identify: 1) the mechanism of uncontrolled intracellular growth of Salmonella in TBCs, 2) the role(s) of IFN-?? in susceptibility of TBCs to Salmonella, and 3) the mechanism of Salmonella-induced placental inflammation. Studies will be performed in vitro using primary isolated human trophoblast cells and placental explants, and in vivo using pregnant mouse models. Specific Aim 1 will test the hypothesis that Salmonella thrive within a unique intracellular environment of trophoblast cells. We will elucidate whether different trophoblast subpopulations of differing gestational age specifically promote Salmonella replication due to specific cell-cell interactions. We will also identify the role of bacterial injectisome virulence factors in facilitating entry into TBCs and the relative role of trophoblast phagocytosis. Lastly, we will characterize the molecular features of the intracellular environment (sub-cellular vacuole) in which Salmonella proliferates. Specific Aim 2 will test the hypothesis that trophoblastic hypo-responsiveness to IFN-?? contributes to susceptibility to Salmonella. We will test whether IFN-? pre- treatment of TBCs can contain Salmonella infection, how Salmonella modulates the JAK-STAT-1 signaling pathway in TBCs, and if knocking down negative-feedback inhibitors of IFN-?? signaling such as SOCS expression can aid resolution of TBC-Salmonella infection. Specific Aim 3 will test the working hypothesis that the mechanism of ST-induced TBC death is distinct from that encountered in other infected cells and contributes to overt inflammation. We will identify differential inflammation (IL-1?, IL-18, caspase) and/or cell death signaling (apoptosis, pyroptosis or necroptosis) as a cause of TBC susceptibility to Salmonella. Overall we expect to identify the relative importance of unique trophoblast features versus Salmonella virulence factors in destruction of the placenta. This contribution will significantly reshape our understanding of infection risk during pregnancy. Successful completion of this study will represent the critical first step in the continuum of research requird to develop rational treatment regimens for management of placental infections during pregnancy.

描述（由申请人提供）：孕妇感染侵袭性沙门氏菌的风险很高，这可能导致母体和胎儿并发症。我们发现，沙门氏菌感染孕鼠导致快速胎儿和母体死亡，由于大量的细菌增殖的胎盘滋养层细胞（TBCs）。在体外，沙门氏菌蓬勃发展的人滋养层来源的绒毛膜癌细胞。然而，我们对妊娠期间沙门氏菌感染易感性增加的机制的认识存在差距。我们的长期目标是开发可以控制孕妇细胞内感染结果的策略。本申请的总体目标是鉴定使TBC对沙门氏菌高度敏感的分子机制。我们的中心假设是，胎盘TBCs被沙门氏菌感染，并提供了一个独特的细胞内生态位，允许不受控制的有毒沙门氏菌复制，由于无效的免疫反应，导致胎盘死亡。我们的中心假设将通过三个具体目标进行验证，这些目标将确定：1）TBCs中沙门氏菌不受控制的细胞内生长的机制，2）IFN-γ？TBCs对沙门氏菌的易感性; 3）沙门氏菌诱导胎盘炎症的机制。将使用原代分离的人滋养层细胞和胎盘外植体进行体外研究，并使用妊娠小鼠模型进行体内研究。具体目标1将测试沙门氏菌在滋养层细胞的独特细胞内环境中生长的假设。我们将阐明是否不同的滋养层细胞亚群的不同胎龄，特别是促进沙门氏菌的复制，由于特定的细胞-细胞相互作用。我们还将确定细菌注射毒力因子在促进进入TBCs中的作用以及滋养层吞噬作用的相对作用。最后，我们将描述沙门氏菌增殖的细胞内环境（亚细胞空泡）的分子特征。具体目标2将测试的假设，滋养层细胞低反应IFN-？？导致对沙门氏菌的易感性。我们将测试是否IFN-？TBCs的预处理可能包含沙门氏菌感染，沙门氏菌如何调节TBCs中的JAK-STAT-1信号通路，以及是否敲除IFN-γ的负反馈抑制剂？信号传导如SOCS表达可以帮助解决TBC-沙门氏菌感染。具体目标3将测试工作假设，即ST诱导的TBC死亡的机制与其他感染细胞中遇到的机制不同，并有助于明显的炎症。我们将确定不同的炎症（IL-1？，IL-18、半胱天冬酶）和/或细胞死亡信号传导（细胞凋亡、细胞凋亡或细胞坏死）作为TBC对沙门氏菌易感性的原因。总的来说，我们希望确定独特的滋养层特征与沙门氏菌毒力因子在胎盘破坏中的相对重要性。这一贡献将大大重塑我们对怀孕期间感染风险的理解。本研究的成功完成将代表为管理妊娠期间胎盘感染开发合理治疗方案所需的连续研究的关键第一步。