ER-phagy in the functional conversion of the Brucella-containing vacuole

内质网吞噬在含布鲁氏菌液泡功能转换中的作用

• 批准号: 10793320
• 负责人: JEAN A CELLI
• 金额: $ 19.5万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-20 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10793320
• 关键词: Automobile Driving; Autophagocytosis; Autophagosome; Bacteria; Binding; Biogenesis; Brucella; Brucella abortus; Cell Compartmentation; Cell physiology; Communicable Diseases; Data; Dedications; Endoplasmic Reticulum; Evolution; Immune; Immunologic Receptors; Infection; Knowledge; Label; Life Style; Mammalian Cell; Mediating; Membrane; Microbe; Modeling; Molecular; Nature; Organelles; Pathway interactions; Phagocytes; Phagosomes; Process; Proliferating; Proteins; Regulation; Role; Signal Transduction; Testing; Type IV Secretion System Pathway; Vacuole; Virulence; Zoonoses; biological adaptation to stress; experimental study; immune function; improved; innate immune function; microbial; novel; pathogen; pathogenic bacteria; pathogenic microbe; permissiveness; receptor; recruit; response; sensor

Project Summary Intracellular microbes with a vacuolar lifestyle share an ability to remodel host cell compartments and functions to support specific stages of their infectious cycle. The cellular and molecular details of how microbial vacuoles functionally evolve during a pathogen’s intracellular cycle to promote their virulence are not well understood. Here we aim to define cellular processes driving the functional evolution of the intracellular vacuole of the zoonotic bacterium Brucella abortus, which transitions from a replicative niche to an egress organelle. B. abortus primarily infects phagocytes and remodels its original phagosome into the replicative Brucella-containing vacuole (rBCV), an organelle derived from the host endoplasmic reticulum (ER) that supports intracellular proliferation. rBCVs subsequently convert into autophagosome- like vacuoles (aBCVs) that mediate post-replication bacterial egress. Autophagy is a conserved eukaryotic process of selective or non-selective capture of cellular content within membrane-bound autophagosomes for lysosomal degradation, including the selective degradation of organelles such as the ER via dedicated autophagy receptors. We have shown that aBCV biogenesis from rBCVs requires a subset of conventional autophagic machineries and an active bacterial VirB Type IV secretion system, but the process, selectivity and regulation of this vacuolar conversion remain enigmatic. Brucella infection triggers the Unfolded Protein Response (UPR) during the rBCV stage via the innate immune sensor STING, provoking an ER- centered stress response that promotes bacterial replication within rBCVs. Whether the UPR also contributes to aBCV biogenesis is unknown. STING-dependent UPR induces ER-phagy, whose selectivity could mechanistically drive the capture of ER-derived rBCVs by autophagosomes to form aBCVs. Based on preliminary evidence that i) Brucella infection influences ER-phagy; ii) rBCVs recruit distinct ER-phagy receptors and iii) STING is required for aBCV biogenesis, here we will test the overall hypothesis that aBCV biogenesis is mediated by selective ER-phagy of rBCVs via a STING-dependent process. Aim1 will determine i) whether Brucella modulates ER-phagy, ii) whether specific ER-phagy receptors are required for aBCV biogenesis and iii) the autophagic cascade engaged during aBCV biogenesis. Aim 2 will determine whether the role of STING in aBCV biogenesis is via induction of the UPR or its activity as an ER-phagy receptor. The successful completion of these aims will establish new concepts of functional evolution of bacterial vacuoles, a common feature of the infectious cycle of many microbial pathogens that is poorly understood.

项目摘要 具有空泡生活方式的细胞内微生物具有重塑宿主细胞隔间和 支持其感染周期的特定阶段的功能。细胞和分子的细节是如何 微生物空泡在病原体的细胞内周期中功能性地进化，以促进其毒力 不是很清楚。在这里，我们的目标是定义推动细胞功能进化的细胞过程 人畜共患病布鲁氏菌的细胞内液泡，它从复制的生态位过渡 送到一个出口细胞器。流产杆菌主要感染吞噬细胞，并将其原始吞噬小体重塑为 含有布鲁氏菌的复制型液泡(RBCV)是一种来源于寄主内质的细胞器 支持细胞内增殖的网状结构(ER)。RBCV随后转换为自噬小体- 如介导复制后细菌外泄的空泡(ABCV)。自噬是一种保守的真核生物 在膜结合的自噬体内选择性或非选择性捕获细胞内容的过程 对于溶酶体的降解，包括对细胞器如内质网的选择性降解 自噬受体。我们已经证明，从rBCV进行aBCV生物生成需要传统 自噬机制和活性细菌VIRB IV分泌系统，但过程、选择性 而这种液泡转换的调控仍然是个谜。布鲁氏菌感染引发未折叠 在rBCV阶段，蛋白质反应(UPR)通过先天性免疫传感器刺痛，引发ER- 促进rBCV内细菌复制的中心应激反应。普遍定期审议是否也 对aBCV生物发生的贡献尚不清楚。依赖刺的UPR诱导ER吞噬，其选择性 可以机械地推动自噬小体捕获内质网来源的rBCV形成aBCV。基座 根据初步证据，i)布鲁氏菌感染影响ER吞噬；ii)rBCV招募明显的ER吞噬 受体和iii)叮咬是BCV生物发生所必需的，在这里我们将检验总体假设 ABCV的生物发生是通过依赖于刺的过程选择性地吞噬rBCV的内质网介导的。Aim1将 确定一)布鲁氏菌是否调节ER吞噬，二)是否需要特定的ER吞噬受体 对于aBCV生物发生，以及iii)在aBCV生物发生过程中参与的自噬级联。目标2将 确定刺痛在aBCV生物发生中的作用是通过诱导UPR还是其作为一种 ER-吞噬受体。这些目标的成功实现将建立新的功能概念 细菌空泡的进化，这是许多微生物病原体感染循环的共同特征 人们对此知之甚少。