Characterizing the Contribution of the Group B Streptococcal Surface Adhesin BspC Interaction with Host Vimentin to Disease and Colonization

项目总结 B组链球菌，又称无乳链球菌，是一种革兰氏阳性、-溶血性 通常在人类胃肠道和泌尿生殖道中发现的细菌。GBS仍然是 新生儿和某些成人人群中的侵袭性疾病，包括孕妇。的发展。 GBS疾病是由女性生殖道的无症状定植引起的，在怀孕期间可以 与绒毛膜羊膜炎、产后子宫内膜炎和早产有关。约20%-30% 健康的女性会在直肠阴道内感染GBS；这些女性所生的大多数婴儿都会 它们自己就会被细菌侵占。新生儿感染也是由上升感染引起的 细菌通过胎盘膜在子宫内引发感染。GBS是本病的主要病因 新生儿细菌性脑膜炎和GBS脑膜感染可导致10%-15%的死亡率 抗生素治疗。此外，多达40%的幸存者会出现永久性的神经后遗症，包括 认知缺陷、癫痫发作和脑缺血。进入中枢神经系统(CNS)和 引起脑膜炎血液传播的球蛋白必须穿透血脑屏障；然而，人们对此知之甚少 GBS和BBB之间的第一个也是最关键的相互作用，它启动了细菌交叉和疾病 进步。这项建议试图表征一个新发现的GBS抗原I/II家族粘附素的作用， BSPC与定植和中枢神经系统疾病的发病机制有关。我们最近确定BSPC 促进对血脑屏障内皮细胞的附着，有助于GBS脑膜炎的发展。更进一步，我们 已经发现BSPC与波形蛋白直接相互作用，波形蛋白是一种广泛分布的中间丝蛋白 在血管内皮细胞中发现。该提案旨在确定BSPC上与以下内容交互的区域 波形蛋白，并表征这种相互作用在GBS脑膜炎和女性定植中的作用 生殖道。我假设结合区包含在球状可变区(V- BSPC)，并导致GBS脑膜炎和阴道定植/上升感染。这些 假说将通过体外和体内的血脑屏障穿透和阴道定植模型来解决。 在以下具体目标中：目标1：确定BSPC V结构域所需的关键区域和氨基酸- 波形蛋白相互作用；目的2：研究BSPC和波形蛋白在女性生殖道中的作用。这些 数据将阐明抗原I/II蛋白在GBS定植和疾病中的关键作用，并提供 基本的机械洞察力，可能会为防止殖民和 最终导致细菌性脑膜炎。

PROJECT SUMMARY Group B Streptococcus (GBS, also known as Streptococcus agalactiae) is a Gram-positive, -hemolytic bacterium normally found in the human gastrointestinal and urogenital tracts. GBS remains a leading cause of invasive disease in newborns and certain adult populations including pregnant women. The development of GBS disease is initiated by the asymptomatic colonization of the female genital tract and during pregnancy can be associated with chorioamnionitis, puerperal endometritis and preterm labor. Approximately 20-30% of healthy women are colonized rectovaginally with GBS; the majority of infants born to these women will themselves become colonized with the bacterium. Newborn infection also results from ascending infection of the bacterium through the placental membranes to initiate infection in utero. GBS is the principle etiologic agent of neonatal bacterial meningitis, and GBS meningeal infection results in 10-15% mortality despite antibiotic treatment. Additionally, up to 40% of survivors develop permanent neurological sequelae, including cognitive defects, seizure activity, and cerebral ischemia. To access the central nervous system (CNS) and cause meningitis blood-borne GBS must penetrate the blood-brain barrier (BBB); however, little is known about the very first and crucial interaction between GBS and the BBB that initiates bacterial crossing and disease progression. This proposal seeks to characterize the role of a newly identified GBS Antigen I/II family adhesin, BspC, to the pathogenesis of colonization and CNS disease. We have recently determined that BspC promotes attachment to BBB endothelium and contributes to the development of GBS meningitis. Further we have discovered that BspC interacts directly with vimentin, a widely distributed intermediate filament protein found in blood vessel endothelial cells. Thisproposal seeks toidentify the region on BspC that interacts with vimentin, and to characterize the role of this interaction in GBS meningitis and colonization of the female reproductive tract. I hypothesize that the binding region is contained within the globular variable domain (V- domain) of BspC and contributes to both GBS meningitis and vaginal colonization/ascending infection. These hypotheses will be addressed with both in vitro and in vivo models of BBB penetration and vaginal colonization in the following specific aims: Aim 1: Identify the critical regions and amino acids required for BspC V-domain- vimentin interaction; Aim 2: Characterize the role of BspC and vimentin in the female reproductive tract. These data will clarify the crucial role of Antigen I/II proteins to GBS colonization and disease and provide fundamental mechanistic insights that may inform new treatment strategies to prevent colonization and ultimately bacterial meningitis.