Outer Membrane Proteins of Pathogenic Oral Treponemes Inhibit Actin Rearrangement and Antimicrobial Functions of Neutrophils

牙周病是一种由细菌引起的炎症，在美国47%的成年人受到影响 也是全球牙齿脱落的头号原因。这种情况的特点是 牙齿支持结构由宿主免疫系统和正常宿主之间的生物失调引起 共生口腔生物膜。齿密螺旋体、麦芽密螺旋体和溶卵磷脂密螺旋体分别为 与严重牙周相关的多菌生物膜中丰富的三种未被研究的细菌种类 目前尚缺乏对其致病特性的全面了解。丹蒂科拉，最-好的- 研究了口腔螺旋体，有一个突出的毒力因素：主要的外鞘蛋白(MSP)，它 失调宿主细胞的功能，包括中性粒细胞。麦芽假单胞菌和溶卵磷脂单胞菌 类MSP外膜蛋白分别称为MSPA和MspTL。中性粒细胞是关键的先天免疫 通过协调细胞信号，结构元素， 和细胞功能。MSP通过破坏磷脂酰肌醇、细胞脂的平衡来抑制中性粒细胞功能 代谢产物是细胞内信号传递的关键。这种干扰涉及PI3激酶(PI3K)调节的改变 以及磷酸酶和张力蛋白同源蛋白(PTEN)轴，导致肌动蛋白不适当的重塑 细胞骨架、趋化性受损和中性粒细胞功能改变。我们知识中的一个剩余缺口是 这些未被充分研究的密螺旋体蛋白如何调节肌动蛋白动力学以损害其他重要的中性粒细胞 属性。这个项目的总体目标是描述这些密螺旋体物种和它们的 表面蛋白调控中性粒细胞细胞骨架信号通路和颗粒释放促进 生死存亡。我们假设MSP样蛋白失调调节中性粒细胞肌动蛋白重塑以促进细菌 生死存亡。为了验证这一假说，这个项目的目的是(1)表征MSP蛋白对 PI3K/PTEN轴和肌动蛋白分支动力学以及(2)评估密螺旋体及其MSP的能力 通过调节中性粒细胞募集和脱颗粒来促进生存的蛋白质。为达致这些目标，我 将利用各种方法，包括肌动蛋白掺入分析，免疫学技术， 显微镜、流式细胞术、动物模型、分子生物学和微生物学技术。完成 该项目将对螺旋体和免疫系统之间的相互作用提供有价值的见解，并 这些关系是如何推动疾病进展的。指导和培训计划将在 布法罗大学的多学科研究环境将为我提供科学和 成功过渡到成功研究的下一阶段所需的专业发展技能 职业生涯。

Periodontal disease is a bacterially induced inflammatory condition affecting 47% of adults in the United States and is the number one cause of tooth loss worldwide. This condition is characterized by the destruction of tooth-supporting structures resulting from dysbiosis between the host immune system and the normally commensal oral biofilm. Treponema denticola, Treponema maltophilium, and Treponema lecithinolyticum are three understudied bacterial species abundant in the polymicrobial biofilm associated with severe periodontal disease, and a complete understanding of their pathogenic properties is lacking. T. denticola, the most-well- studied oral spirochete, has a prominent virulence factor: the major outer sheath protein (Msp) that dysregulates the functions of host cells, including neutrophils. T. maltophilium and T. lecithinolyticum have Msp-like outer membrane proteins called MspA and MspTL, respectively. Neutrophils are key innate immune cells that protect oral tissues from pathogenic bacteria by coordinating cellular signaling, structural elements, and cell function. Msp inhibits neutrophil function by disrupting the balance of phosphoinositides, cellular lipid metabolites key for intracellular signaling. This disruption involves altered regulation of the PI3 kinase (PI3K) and phosphatase and tensin homolog (PTEN) axis, leading to inappropriate remodeling of the actin cytoskeleton, impaired chemotaxis, and altered functioning of neutrophils. A remaining gap in our knowledge is how these understudied Treponema proteins modulate actin dynamics to impair other crucial neutrophil properties. The overall objective of this project is to characterize how these Treponema species and their surface proteins manipulate neutrophil cytoskeleton signaling pathways and granule release to promote survival. We hypothesize that Msp-like proteins dysregulate actin remodeling in neutrophils to promote bacterial survival. To test this hypothesis, this project aims to (1) characterize the effects of Msp proteins on the PI3K/PTEN axis and actin branching dynamics and (2) assess the ability of Treponema species and their Msp proteins to promote survival by modulating neutrophil recruitment and degranulation. To achieve these aims, I will utilize a variety of methods, including analyses of actin incorporation, immunological techniques, microscopy, flow cytometry, animal models, molecular biology, and microbiological techniques. Completion of this project will provide valuable insight into the interactions between spirochetes and the immune system and how these relationships drive disease progression. The mentoring and training plan to be performed within the multidisciplinary research environment at the University at Buffalo will provide me with the scientific and professional development skills necessary to successfully transition to the next stage of a successful research career.