Regulatory mechanisms of temporal microglia phenotype expression in a neonatal rat model of infection-sensitized hypoxic ischemic brain injury

围产期窒息是指在出生之前、期间或之后缺氧和血液流动，是全球儿童死亡的主要原因之一。它可以影响所有器官系统，但最可怕的结果，主要影响新生儿的大脑，是缺氧缺血性脑病（HIE），经常导致死亡或在以后的生活中显著发病率。尽管低温治疗已成为HIE的标准治疗方法，但仍有大约50%的低温新生儿死亡或发展为严重残疾。早期识别这些无反应者尚不可能，但迫切需要，因为他们可能受益于额外的治疗方案。围产期感染增加了对缺氧缺血性损伤的易感性，并对受影响新生儿的预后产生负面影响。我们已经建立了感染致敏性缺氧缺血性脑损伤动物模型（双击模型），并表明TH在该模型中不是一种可行的治疗选择，表征一组无反应。这种双重打击模型使我们有机会在一组确定的无反应者中调查潜在的机制。我们已经证明小胶质细胞在我们的双重打击模型中是关键的参与者，并有助于脑损伤。由于双打击的相互作用和调控尚不清楚，本项目旨在描述我们的炎症致敏性缺氧缺血性脑损伤双打击模型中小胶质细胞激活和不同小胶质细胞表型表达的调控机制。随着时间的推移，我们将重点关注微rna在小胶质细胞调节和表型表达中的作用。此外，我们将在我们的双击模型中研究NLRP3炎症小体的作用，它在小胶质细胞激活过程中的影响，它通过mirna的调节以及它对脑损伤严重程度的影响。最后，我们将在我们的双重打击模型中研究另一种神经保护治疗（促红细胞生成素）的效力，描述其对小胶质细胞表型激活的影响和途径。目的是开发强大的生物标志物和治疗靶点，这些靶点将在临床研究中进行测试，早期识别对治疗性低温无反应的患者。

Perinatal asphyxia, describing the lack of oxygen and blood flow before, during, or just after birth, is one of the leading causes of global child death. It can affect all organ systems, however the most frightened resulting condition, predominantly affecting the newborn brain, is hypoxic ischemic encephalopathy (HIE) often resulting in mortality or significant morbidity in later life. Even though therapeutic hypothermia (TH) has become standard treatment for HIE, around 50% of cooled newborns still die or develop severe disability. Early identification of these non-responders is not possible yet, but urgently needed, as they might benefit from additional treatment options. Perinatal infection increases the vulnerability to hypoxic-ischemic injuries and negatively influences the prognosis of affected newborns. We have developed an animal model of infection-sensitized hypoxic-ischemic brain injury (double-hit model) and showed that TH is not a viable treatment option in this model, characterizing one group of non-responders. This double-hit model gives us the opportunity to investigate the underlying mechanisms in a defined group of non-responders. We have shown that microglia cells are key players in our double-hit model and contribute to brain injury. As the interaction and regulation of the double-hit is not known yet, this project aims to describe the regulatory mechanisms responsible for microglia activation and different microglia phenotype expression in our double-hit model of inflammation-sensitized hypoxic-ischemic brain injury in newborn rats. We will focus on the role of micro-RNAs in microglia modulation and phenotype expression over time. Additionally, we will investigate the role of the NLRP3 inflammasome, its impact during microglia activation, its regulation by miRNAs and its impact on severity of brain injury in our double-hit model. Last, we will investigate the potency of an additional neuroprotective treatment (Erythropoietin) in our double-hit model, describing its influence and pathway on microglia phenotype activation. The aim is to develop robust biomarkers and therapeutic targets, which will be tested in clinical studies, early identifying non-responders to therapeutic hypothermia.