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: 10508228
• 负责人: JEAN A CELLI
• 金额: $ 22.95万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 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 2023-01-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10508228
• 关键词: Automobile Driving; Autophagocytosis; Autophagosome; Bacteria; Biogenesis; Brucella; Brucella abortus; Cell Compartmentation; Cell physiology; Communicable Diseases; Data; 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; Proteins; Regulation; Role; Signal Transduction; Testing; Type IV Secretion System Pathway; Vacuole; Virulence; Zoonoses; base; biological adaptation to stress; experimental study; immune function; improved; innate immune function; microbial; novel; pathogen; pathogenic bacteria; pathogenic microbe; 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 具有液泡生活方式的细胞内微生物具有重塑宿主细胞室的能力，并且 支持其感染周期的特定阶段的功能。细胞和分子细节 在病原体的细胞内周期中，微生物吸尘器在功能上进化以促进其病毒 不太了解。在这里，我们旨在定义驱动驱动功能演化的细胞过程 人畜共患细菌的细胞内真空虫，布鲁氏菌堕胎，从复制生态位过渡 到出口细胞器。 B. aportus原发性感染吞噬细胞并将其原始吞噬体重塑为 含brucella的复制胶水（RBCV），这是一种源自宿主内皮塑料的细胞器 支持细胞内增殖的网状（ER）。 RBCV随后转化为自噬体 - 就像介导复制后细菌出口后的真空（ABCV）一样。自噬是保守的真核 选择性或非选择性捕获膜结合自噬体内细胞含量的过程 对于溶酶体降解，包括通过专用的细胞器（例如ER）的选择性降解 自噬接收器。我们已经表明，来自RBCV的ABCV生物发生需要一部分常规 自噬的机器和活性细菌VIRB IV型分泌系统，但选择性，选择性 这种真空旋转转换的调节仍然神秘。布鲁氏菌感染触发了展开的 在RBCV阶段，蛋白质反应（UPR）通过先天免疫刺激 促进RBCV内细菌复制的中心应力反应。是否也 有助于ABCV生物发生尚不清楚。 sting依赖性UPR诱导ER-Phagy，其选择性 可以机械地驱动自噬体捕获ER衍生的RBCV以形成ABCV。基于 关于初步证据，i）布鲁氏菌感染会影响ER-PHAGY； ii）RBCVS招募独特的ER-Phagy 接收器和iii）ABCV生物发生需要刺痛，在这里我们将测试总体假设，即 ABCV生物发生是由RBCV的选择性ER-Phagy通过sting依赖性过程介导的。 AIM1将 确定i）布鲁氏菌是否调节er-phagy，ii）是否需要特定的er-phagy接收器 对于ABCV生物发生和iii）在ABCV生物发生过程中参与的自噬级联反应。 AIM 2意志 确定STIN在ABCV生物发生中的作用是通过诱导UPR还是其活性作为一种 ER-PHAGY接收器。这些目标的成功完成将建立功能的新概念 细菌吸尘器的进化，这是许多微生物病原体感染周期的共同特征 理解很差。