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

项目总结： 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不同。我们 发现大鼠出生后第二周是小脑发育的敏感期 炎症引起的调节失调。这一敏感时期的特点是前列腺素的产生增加，在 特别是PGE2。这一敏感期恰逢围产期缺氧缺乏症(如人类出生)风险增加的时期 婴儿)。炎症后浦肯野神经元树突状细胞发育迟缓的原因不明。小胶质细胞 是大脑的先天免疫细胞，在健康和疾病中都有多种功能。我们一直在密切观察 发育中小脑小胶质细胞的时间调控吞噬活性及假设 这对正常的小脑发育起着重要作用。我们提供的证据表明，PN10的H/I仍在增加 此外，吞噬作用的高峰期通常出现在PN17。调节小胶质细胞吞噬活性的关键信号之一是 膜脂磷脂酰丝氨酸，外化于外叶，促进吞噬作用。低氧 已知通过给细胞施加足够的压力以使磷脂酰丝氨酸外化来刺激吞噬作用。的作用 代谢或脂筏在这种脂质的外化中没有被考虑，也没有这两个变量 在测量状态与激活状态下的小胶质细胞的特征。 缺氧-缺血性脑损伤通常发生在炎症性侮辱之后，导致进一步的损伤。 否则就会发生。在发育中的小脑中是否如此还没有被仔细地研究过，也没有性行为 考虑了缺氧缺血性脑损伤或炎症性损伤的差异。我们提出了三个具体的目标 1)H/I后浦肯野神经元、颗粒细胞和小脑深核团的形态计量学 炎症，2)小胶质细胞在有无炎症的H/I所致神经元损伤中的作用 四环素类抗生素米诺环素的作用及谷氨酸转运体的修饰 抗生素头孢曲松作为一种潜在的治疗方法。我们还将探讨膳食补充剂、胆碱和 评估损伤和恢复的行为和组织学分析。这些实验产生的数据将提供 H/I对小脑的影响及其对认知障碍影响程度的新见解 以及患有缺氧缺血性脑病的婴儿的运动功能。

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.