A bacterial biosensor for intracellular metal availability in the gut

用于肠道内细胞内金属可用性的细菌生物传感器

• 批准号: 10763683
• 负责人: Leigh Knodler
• 金额: $ 20.01万
• 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: 2022-04-22 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10763683
• 关键词: bacterial; biosensor; intracellular; metal; availability; bacterial; biosensor; intracellular; metal; availability

PROJECT SUMMARY Of the foodborne bacterial, protozoal and viral diseases, non-typhoidal Salmonella enterica cause the largest burden of illness and death worldwide. The most common human clinical isolates are Salmonella enterica serovars Typhimurium (S. Typhimurium, STm) and Enteriditis (S. Enteriditis). Infection can cause either a self- limiting gastroenteritis or a life-threatening, invasive disease in immunocompromised individuals. During enteric infection, STm adopts both extracellular and intracellular lifestyles, colonizing the intestinal lumen as well epithelial cells and phagocytes in the intestinal mucosa. Here we will study how host-mediated restriction of transition metals, known as nutritional immunity, affects STm colonization of the gut. The NRAMP family of proteins are “promiscuous” transporters of divalent cations that play a major role in metal ion homeostasis from bacteria to man. In mammals, there are two NRAMP genes, SLC11A1 and SLC11A2 in humans and Slc11a1 and Slc11a2 in mice. Slc11a1 is restricted to the myeloid lineage whereas Slc11a2 is ubiquitously expressed. Whilst the role of Slc11a1 in controlling intracellular bacterial and parasitic infections in macrophages and mice is undisputed, whether Slc11a2 also contributes to antimicrobial functions is unknown. Our general hypothesis is that intracellular metal ion availability differs in epithelial cells and phagocytes in the gut due to the distinct cell-type expression of SLC11A1 and SLC11A2. First, we will use microbial biosensors of metal ion concentrations to infect bovine ligated ileal loops, a highly relevant model of enteric salmonellosis in humans, and map the spatiotemporal distribution of metal ion deprivation in the gut. Second, we will define whether SLC11A2, the sole NRAMP family member expressed in intestinal epithelial cells, defends against invading pathogens via metal nutrient limitation. Completion of this proposal will close a significant knowledge gap about host-microbe competition for metal ions in the gut during enteric infection.

项目摘要 在食源性细菌，原生动物和病毒疾病中，非细类沙门氏菌肠道导致最大的 全球疾病和死亡负担。最常见的人类临床分离株是肠沙门氏菌 血清伤寒（S. typhimurium，STM）和肠炎（S.肠炎）。感染会引起自我 限制胃肠炎或免疫功能低下的个体中威胁生命的侵入性疾病。在输入期间 感染，STM同时采用细胞外和细胞内生活方式，也定居于肠腔 肠粘膜中的上皮细胞和吞噬细胞。在这里，我们将研究宿主介导的限制 过渡金属（称为营养免疫）会影响肠道的STM定植。 Nramp家族 蛋白质是二价阳离子的“混杂”转运蛋白，在金属离子稳态中起主要作用 人类的细菌。在哺乳动物中，人类和SLC11A1中有两个NRAMP基因，Slc11a1和Slc11a2 和小鼠中的slc11a2。 SLC11A1仅限于髓样谱系，而SLC11A2无处不在。 而SLC11A1在控制巨噬细胞中细胞内细菌和寄生虫感染中的作用 无可争议的是，SLC11A2是否也有助于抗菌功能。我们的一般假设 是由于不同的细胞内金属离子的可用性差异，因此由于明显的 SLC11A1和SLC11A2的细胞类型表达。首先，我们将使用金属离子的微生物生物传感器 感染牛的浓度是结扎的回肠环，这是一种高度相关的人类肠道疾病模型， 并绘制肠道中金属离子剥夺的时空分布。第二，我们将定义是否 Slc11a2是在肠上皮细胞中表达的唯一NRAMP家族成员，可防止入侵 通过金属养分限制病原体。该提案的完成将缩小有关的重大知识差距 肠道感染期间，肠道中金属离子的宿主微型竞争。