COX-2 and Injury in the Immature Brain

描述（由申请人提供）：有一个短暂的增加期 对缺氧缺血和兴奋性氨基酸（EAA）介导的脑敏感性 与突触连接的发展平行的损伤， 发育中的大脑中EAA受体的成熟。 在啮齿类动物中， 对脑损伤的敏感性增加发生在出生后1-3周之间。 诱导型环氧合酶（考克斯-2）受发育调节 由突触活动诱导并被EAA下调的基因 对手。 因此，神经元考克斯-2的产生在 最大的突触增殖与增加的时期相一致 易受缺氧缺血性和兴奋毒性脑损伤的影响， 出生后1-3周。 最近，考克斯-2已被鉴定为 促进成熟啮齿动物中缺血性脑损伤的发展。 这些观察结果表明，考克斯-2可能是一个未被认识的调解人， 发育调节的缺氧缺血性和兴奋毒性易感性 未成熟大脑的脑损伤。 缺氧缺血能力与EAA 诱导发育中的脑中考克斯-2表达的毒性以及 考克斯-2在发育中的脑损伤后的抑制作用还没有被证实。 研究了 因此，候选人建议测试假设， 诱导考克斯-2可加重缺氧缺血和EAA介导的脑损伤 大脑发育 此外，候选人将使用组织培养和基因 敲除技术研究考克斯-2毒性的潜在机制。 也就是说，他将研究考克斯-2和一氧化氮 合成酶（NOS）协同有助于形成高毒性的 活性氧过氧亚硝酸盐。 这是一条很有吸引力的调查线索 因为神经元NOS是一个发育调控的基因，具有时间分布， 表达镜像考克斯-2表达，因为它会暴露 候选人的实验使用组织培养和基因敲除技术。 候选人的长远目标是发展成为一个独立的 临床科学家与完整的电池的研究技能和 指导其他临床科学家的能力。 指导临床 科学家发展奖将允许继续获得优秀的 导师，并将增加获得新研究的时间 skills. 拟议的实验利用校园内的专业知识， 两种具有重要科学意义的分子--考克斯和NOS。 拟议 实验为候选人提供了丰富多样的 当代分子生物学工具，将促进他的发展， 儿科急诊医学的临床科学家，同时促进 深入研究考克斯-2神经毒性的机制。 了解这些机制具有潜在的临床重要性，因为 通常用于严重受伤的婴儿和儿童的治疗 (e.g., NSAIDS、类固醇等）可以影响考克斯-2的产生， 同工型特异性考克斯-2抑制剂最近已在临床上可用。

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.