The Role of Pericytes in the Vascular Dysfunction of Sepsis

项目总结： 败血症每年影响1900多万人。随着治疗策略的改进，越来越多的 患者在脓毒症中存活下来。这些幸存者中的大多数都会出现认知障碍和心理健康 有问题。然而，促进脓毒症相关性脑病(SAE)的机制在很大程度上仍然存在。 未知，而且缺乏针对SAE的靶向治疗。我们研究计划的长期目标是 了解脓毒症后导致脑血管功能障碍和认知功能障碍的机制 为脓毒症引起的认知功能障碍开发新的靶向治疗方法。为了实现这一目标，我们 利用动物模型表征脓毒症引起的认知功能障碍。我们观察到老鼠表现出 海马区依赖的记忆障碍与病理性神经元功能障碍相关。要理解 脓毒症后认知障碍背后的机制，我们专注于大脑中称为 周细胞在调节脑血流和维持血脑屏障完整性方面发挥重要作用。 周细胞构成神经血管单位的一部分，以满足大脑的能量需求，并促进神经- 炎症反应。然而，周细胞在脓毒症引起的认知损害中的作用仍然存在。 未知。我们的研究表明，转录因子Friend白血病病毒整合1(Fli-1) 调节周细胞的激活和活性。我们还观察到脓毒症后脑周细胞数量减少。 周细胞在最初激活和产生炎症介质后发生了凋亡。 周细胞丢失导致血管渗漏和炎性单核细胞募集。我们之前报道过 Fli-1通过调节caspase1/3的表达来调控周细胞的活性。在我们的初步研究中，我们 证实周细胞Fli-1基因敲除小鼠表现出炎症介质产生的减少 致内毒素。更重要的是，我们证明了Fli-1在脑缺血后海马区的表达水平较高。 败血症患者的死亡脑组织与对照组的比较。在此R35/Mira应用程序中，我们建议使用 新开发的、无偏倚的方法，如单核RNA测序和成像质量细胞术 与我们实验室建立的可诱导周细胞特异性Fli-1基因敲除小鼠和新型反义小鼠一起 本课题组最近开发了针对Fli-1的寡核苷酸Gapmer，以了解周细胞在 脓毒症后的血管功能障碍和认知功能障碍。成功完成拟议的研究 将有助于更好地了解脓毒症后血管认知障碍的机制和 开发新的SAE靶向治疗方法。

Project Summary: Sepsis affects more than 19 million people each year. With improved treatment strategies, more and more patients survive sepsis. The majority of these survivors develop cognitive impairment and mental health problems. However, the mechanisms that promote sepsis-associated encephalopathies (SAE) remain largely unknown, and there is a lack of SAE-targeted treatments. The long-term goals of our research program are to understand the mechanisms that lead to cerebrovascular dysfunction and cognitive impairment post sepsis and to develop novel targeted treatments for sepsis-induced cognitive impairment. To reach this goal, we characterized sepsis-induced cognitive impairment using animal models. We observed that mice exhibit hippocampus-dependent memory impairment associated with pathological neuron dysfunction. To understand the mechanisms behind cognitive impairment post sepsis, we focused on specialized cells in the brain called pericytes, which play a major role in regulating cerebral blood flow and maintaining blood brain barrier integrity. Pericytes form part of the neurovascular unit to meet the energy demands of the brain and facilitate neuro- inflammatory responses. However, the role of pericytes in sepsis-induced cognitive impairment remains unknown. Our studies demonstrated that the transcription factor friend leukemia virus integration 1 (Fli-1) regulates pericyte activation and viability. We also observed that brain pericyte numbers decreased after sepsis and that pericytes underwent apoptosis after their initial activation and production of inflammatory mediators. Pericyte loss resulted in vascular leakage and recruitment of inflammatory monocytes. We reported previously that Fli-1 governs pericyte viability through regulating caspase 1/3 expression. In our preliminary studies, we demonstrated that pericyte Fli-1 knockout mice exhibit decreased inflammatory mediator production in response to LPS. More importantly, we demonstrated that Fli-1 levels were higher in the hippocampus regions of post- mortem brain tissue from septic patients compared to controls. In this R35/MIRA application, we propose to use newly developed, unbiased approaches such as single nucleus RNA sequencing and imaging mass cytometry alongside inducible pericyte-specific Fli-1 knockout mice generated in our laboratory and novel antisense oligonucleotide Gapmers targeting Fli-1 recently developed by our group to understand the role of pericytes in vascular dysfunction and cognitive impairment post sepsis. The successful completion of the proposed studies will lead to better understanding of the mechanisms of vascular cognitive impairment post sepsis and the development of novel SAE-targeted treatments.