Microbial-mediated blood-brain barrier development at the intersection of the gut-brain axis

项目总结/摘要 血脑屏障（blood-brain barrier，BBB）是控制循环血液与脑组织相互作用的直接界面 中枢神经系统（CNS）。目前的肠-脑轴研究已经使肠道与脑之间的联系 微生物组和CNS功能，但在很大程度上绕过BBB，BBB决定是否或什么微生物 介质将进入中枢神经系统对脑功能产生影响。这些潜在影响的另一个方面 循环微生物因素是对血脑屏障成分的直接影响。早产率呈上升趋势 由于长期早产相关的神经发育缺陷，给医疗保健和社会带来负担。 败血症、坏死性小肠结肠炎和围产期脑损伤等疾病都与高风险相关 神经发育不良，并与生态失调有关，因此使新生儿 微生物组是改善发育结果的目标。在本提案中，我们旨在测试 与早产相关早期生态失调有助于血脑屏障受损的假说 发育和功能，并对大脑发育和神经系统结果产生长期影响。我们 将利用已建立的知生小鼠转殖方法作为实验平台。三 临床相关微生物群落将用于评价BBB在以下因素影响下的发展： 从产前阶段到出生后早期的肠道微生物群：1）来自早产儿的社区， 出生后的生长; 2）社区从早产儿出生的母亲确诊绒毛膜炎; 3） 来自足月健康婴儿的社区。此外，嗜酸乳杆菌和 双歧杆菌将作为优化BBB发育的策略进行母体给药， 功能BBB完整性，BBB紧密连接的时间发展，组件和转运系统， 将检查表型标记。此外，神经元发育和白色物质成熟在 将调查不同的发育阶段以及少年时期的行为。16 s rRNA基因 人类捐赠者的粪便样本测序，转基因母鼠和后代将用于 表征微生物群落，以确定与BBB相关的不同微生物物种/模式 功能变化。这项研究的新知识将是1）证明早产微生物 从胚胎期到晚期， 出生后时期; 2）鉴定BBB组分内的靶标，其中微生物介质具有 特异性作用; 3）鉴定与BBB发育和功能相关的微生物标志物。此外，委员会认为， 通过测试益生菌在改善微生物组特征、BBB功能和神经功能方面的功效， 结果，我们将确定一种基于微生物组的治疗选择，可以作为一种潜在的有效方法， 减少早产儿神经发育缺陷的策略。

PROJECT SUMMARY/ABSTRACT The blood-brain barrier (BBB) is the direct interface that governs the interaction between the circulating blood and central nervous system (CNS). Current gut-brain axis research has made the association between the gut microbiome and CNS functions but largely bypasses the BBB which determines whether or what microbial mediators will enter CNS to have impacts on brain functions. Another aspect of the potential impacts of these circulating microbial factors is the direct impact on BBB components. Preterm birth represents an increasing burden for healthcare and society due to long term prematurity-associated neurodevelopmental deficits. Morbidities such as sepsis, necrotizing enterocolitis, and perinatal brain injuries are all associated with high risk for poor neurodevelopmental outcomes and have been associated with dysbiosis thus making the neonatal microbiome a target to improve developmental outcomes. In this proposal, we aim to test the overall hypothesis that early dysbiosis associated with preterm birth contributes to compromised blood-brain barrier development and functions, and has long term effects on brain development and neurological outcomes. We will utilize an established gnotobiotic mouse transfaunation method as the experimental platform. Three clinically relevant microbial communities will be utilized to evaluate BBB development under the influence of gut microbiota from prenatal stages to the early postnatal period: 1) Communities from preterm infants with low postnatal growth; 2) Communities from preterm infants born to a mother with confirmed chorioamnionitis; 3) Communities from full term healthy infants. In addition, the combination of Lactobacillus acidophilus and Bifidobacterium infantis will be maternally administrated as a strategy to optimize BBB development and function. BBB integrity, temporal development of BBB tight junction, components and transporter systems with phenotypical markers will be examined. Furthermore, neuronal development and white matter maturation at different developmental stages will be investigated as well as behaviors at a juvenile age. 16S rRNA gene sequencing of fecal samples of human donors, the transfaunated dams and offspring will be used to characterize the microbial communities to determine the distinct microbial species/pattern associated with BBB functional changes. The novel knowledge from this study will be 1) demonstrating that preterm microbial communities can influence BBB development and neurological outcomes from the embryonic stage to the postnatal period; 2) identifying the target(s) within the BBB components where microbial mediators have specific effects; 3) identifying microbial markers associated with BBB development and functions. Furthermore, by testing the efficacy of probiotics in improving microbiome characteristics, BBB function and neurological outcomes, we will identify a microbiome-based therapeutic option that can be used as a potential effective strategy to reduce neurodevelopmental deficits in preterm infants.