COX-2 and Injury in the Immature Brain

描述(由申请人提供)：有一个暂时性的增加 缺氧缺血和兴奋性氨基酸(EAA)介导的脑敏感性 与突触连接性和突触发育平行的损伤 发育中的大脑中EAA受体的成熟。在啮齿动物中，这段时间 对脑损伤的敏感性增加发生在出生后1-3周之间。 环氧合酶的诱导型亚型(COX-2)受发育调节 由突触活动诱导并被EAA下调的基因 对抗者。因此，神经元环氧合酶-2的产生在 突触最大增殖期与突触增高期一致 对发生的缺氧缺血性和兴奋性毒性脑损伤的易感性 出生后1-3周。最近，COX-2被鉴定为 促进成年啮齿动物缺血性脑损伤的发生。 这些观察结果表明，COX-2可能是一种未被认识的 发育调节的对缺氧缺血和兴奋性毒性的易感性 未成熟脑的脑损伤。EAA与缺氧缺血能力的关系 诱导发育脑COX-2表达的毒性及对其的影响 COX-2对发育中脑损伤的抑制作用尚未得到证实 调查过了。因此，候选人建议对假设进行检验 COX-2的诱导加剧缺氧缺血和EAA介导的损伤 发育中的大脑。此外，候选人将使用组织培养和基因 基因敲除技术研究COX-2毒性的潜在机制。 也就是说，他将调查COX-2和一氧化氮 一氧化氮合酶(NOS)协同作用促进高毒力的形成 活性氧类过氧亚硝酸根。这是一条诱人的调查路线 因为神经元型一氧化氮合酶是一种发育调节基因，具有时间分布 它反映了COX-2的表达，因为它将暴露 使用组织培养和基因敲除技术进行实验的候选人。 候选人S的长期目标是发展成为一名独立的 拥有完整研究技能的临床医生科学家和 指导其他临床科学家的能力。带教的临床 科学家发展奖将允许继续访问优秀的 指导，并将增加可用于获得新研究的时间 技能。建议的实验利用了校园内的专业知识， 两个具有重大科学意义的分子--COX和NOS。建议数 实验为候选人提供了丰富多样的 当代分子生物学工具将促进他作为一名 儿科急救医学的临床科学家，同时促进 深入研究COX-2神经毒性的相关机制。 了解这些机制具有潜在的临床重要性，因为 危重婴儿和儿童常用的治疗方法 (例如，非甾体抗炎药、类固醇等)可以影响COX-2的产生和 异构体特异性环氧合酶-2抑制剂最近已进入临床应用。

DESCRIPTION (provided by applicant): There is a transient period of increased sensitivity to hypoxic-ischemic and excitatory amino acid (EAA)-mediated brain injury that parallels the development of synaptic connectivity and EAA-receptor maturation in developing brain. In rodents, this period of increased sensitivity to brain injury occurs between 1-3 wk following birth. The inducible isoform of cyclooxygenase (COX-2) is developmentally regulated gene that is induced by synaptic activity and down-regulated by EAA antagonists. Thus, neuronal COX-2 production is greatest during the period of maximal synaptic proliferation coinciding with the period of increased vulnerability to hypoxic-ischemic and excitotoxic brain injury that occurs from 1-3 wk following birth. Recently, COX-2 has been identified as contributing to the development of ischemic brain injury in mature rodents. These observations suggest that COX-2 may be an unrecognized mediator of developmentally regulated susceptibility to hypoxic-ischemic and excitotoxic brain injury in immature brain. The ability of hypoxia-ischemia and EAA toxicity to induce COX-2 expression in the developing brain and the effect of COX-2 inhibition upon injury to the developing brain has not been investigated. Accordingly, The candidate proposes to test the hypothesis the induction of COX-2 exacerbates hypoxic-ischemic and EAA-mediated injury in the developing brain. In addition, the candidate will use tissue culture and gene knock-out technology to investigate a potential mechanism of COX-2 toxicity. Namely, he will investigate the possibility that COX-2 and nitric oxide synthase (NOS) synergistically contribute to the formation of the highly toxic reactive oxygen species peroxynitrite. This is an attractive line of inquiry because neuronal NOS is a developmentally regulated gene with temporal profile of expression mirroring COX-2 expression and because it will expose the candidate to experiments using tissue culture and gene knock-out technology. The candidate s long-term objective is to develop into an independent clinician scientist with a complete battery of research skills and the capability of mentoring other clinician scientists. A Mentored Clinical Scientist Development Award will allow continued access to excellent mentorship and will increase the time available for attaining new research skills. The proposed experiments take advantage of on-campus expertise with two molecules of significant scientific interest - COX and NOS. The proposed experiments provide the candidate with access to a rich variety of contemporary molecule biology tools that will promote his development as a clinician scientist in Pediatric Emergency Medicine while facilitating an in depth examination of the mechanisms involved in COX-2 neurotoxicity. Understanding these mechanisms is of potential clinical importance because treatments that are commonly used in critically injured infants and children (e.g., NSAIDS, steroids, etc.) can influence COX-2 production and isoform-specific COX-2 inhibitors have recently become clinically available.