Project I- Impact of Hypoxia-Ischemia and/or Inflammation on Microglia in Cerebellum

项目概要： 神经元发育的敏感期因大脑区域、对破坏性物质的敏感性和脆弱性而异。我们 发现大鼠出生后第二周是小脑发育的敏感期， 由炎症引起的失调。这一敏感时期的特征是， 特别是PGE 2。这一敏感期与围产期H/I风险增加的时间相吻合（例如，人类的出生）。 婴儿）。炎症后浦肯野神经元树突树发育迟缓的原因尚不清楚。小胶质 是大脑的先天免疫细胞，在健康和疾病中发挥着各种功能。我们仔细观察了 调节和时间控制的吞噬活动的小胶质细胞在发展中的小脑，我们假设 这在正常小脑发育中起着重要作用。我们提供的证据表明，在PN 10的H/I仍然增加 此外，通常在PN 17看到的吞噬作用的峰值。调节小胶质细胞吞噬活性的关键信号之一是 膜脂质磷脂酰丝氨酸，其外化到外小叶并促进吞噬作用。缺氧 已知通过对细胞施加足够的应力以使磷脂酰丝氨酸外化来刺激吞噬作用。的作用 没有考虑这种脂质外化的代谢或脂筏，也没有考虑这些变量 在小胶质细胞中的特征是处于测量与激活状态。 缺氧缺血性脑损伤通常发生在炎症损伤之后，导致比正常情况下更进一步的损伤。 否则发生。这在发育中的小脑中是否是真的还没有被仔细探索过，也没有性行为。 缺氧缺血性脑损伤或炎性损伤的差异。我们提出了三个具体目标， （1）H/I后浦肯野神经元、颗粒细胞和小脑深核的形态计量学变化 炎症，2）小胶质细胞在有和没有炎症的H/I诱导的神经元损伤中的作用，以及3）小胶质细胞在炎症中的作用。 四环素类抗生素米诺环素作为原理证明的影响和谷氨酸转运蛋白修饰 抗生素头孢曲松作为一种潜在的治疗。我们还将探讨膳食补充剂，胆碱和行为 行为和组织学分析以评估损伤和恢复。这些实验产生的数据将提供 对H/I对小脑的影响及其对认知功能受损的影响程度的新见解 以及缺氧缺血性脑病患儿的运动功能。

PROJECT SUMMARY: Sensitive periods in neuronal development vary by brain region, sensitivity and vulnerability to disruptive agents. We have discovered that the second postnatal week in the rat is a sensitive period in cerebellar development to dysregulation by inflammation. This sensitive period is characterized by increased production of prostaglandins, in particular PGE2. This sensitive period coincides with a time of increased risk for perinatal H/I (e.g. birth in human infants). The source of the stunting of the Purkinje neuron dendritic tree following inflammation is unknown. Microglia are the brains innate immune cells and serve a variety of functions in both health and disease. We have observed tightly regulated and temporally controlled phagocytic activity of microglia in the developing cerebellum and we hypothesize this plays an important role in normal cerebellar development. We provide evidence that H/I at PN10 increases still further the peak in phagocytosis normally seen at PN17. One of the key signals regulating microglia phagocytic activity is the membrane lipid phosphatidylserine, which is externalized to the outer leaflet and promotes phagocytosis. Hypoxia has been known to stimulate phagocytosis by stressing cells sufficiently to externalize phosphotidylserine. The role of metabolism or lipid rafts in the externalization of this lipid has not been considered, nor have either of these variables been characterized in microglia in a surveying versus activated state. Hypoxic-Ischemic brain injury often occurs following an inflammatory insult, resulting in further injury than would otherwise occur. Whether this is true in the developing cerebellum has not been carefully explored nor have sex differences in hypoxic-ischemic brain or inflammatory injury been considered. We propose three Specific Aims focused on 1) morphometery of Purkinje neurons, granule cells and the deep cerebellar nuclei following H/I with and without inflammation, 2) the role of microglia in neuronal damage induced by H/I with and without inflammation and 3) the impact of tetracycline based antibiotic, Minocycline, as proof of principle and the glutamate transporter modifying antibiotic Ceftriaxone as a potential therapeutic. We will also explore the dietary supplement, choline and conduct behavioral and histological analyses to assess injury and recovery. Data generated by these experiments will provide novel insights into the impact of H/I on the cerebellum and the degree to which it contributes to the impaired cognitive and motor function seen in infants suffering hypoxic-ischemic encephalopathy.