Mechanisms of neonatal erythropoietin neuroprotection

新生儿促红细胞生成素神经保护机制

• 批准号: 8928880
• 负责人: SHENANDOAH ROBINSON
• 金额: $ 44.88万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2016-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8928880
• 关键词: Ablation; Address; Adult; Agonist; Anxiety; Attention Deficit Disorder; Autistic Disorder; Axon; Behavioral; Binding; Biological Assay; Brain; Brain Hypoxia-Ischemia; Brain Injuries; Brain-Derived Neurotrophic Factor; Butyric Acids; Calpain; Cations; Cell membrane; Cerebral Palsy; Cerebrum; Child; Chloride Ion; Chlorides; Chronic; Cods; Cognitive; Cognitive Therapy; Cognitive deficits; Data; Development; Embryo; Epilepsy; Erythropoietin; GABA Receptor; Goals; Health; Human; Hypoxia; Immunohistochemistry; Impairment; In Situ Nick-End Labeling; In Vitro; Infant; Inflammatory; Injury; Interneurons; Intervention; Label; Learning; Mechanics; Mediating; Membrane; Messenger RNA; Modeling; Molecular; Motor; NGFR Protein; Neonatal; Neurologic; Neurons; Neuroprotective Agents; Neurotrophic Tyrosine Kinase Receptor Type 2; Operative Surgical Procedures; Outcome; Pathway interactions; Pharmaceutical Preparations; Pregnancy; Premature Birth; Premature Infant; Prenatal Injuries; Problem behavior; Proteins; Rattus; Recovery; Regulation; Rodent; Saline; Seizures; Signal Transduction; Slice; Surface; Techniques; Testing; Time; Trypsin; Up-Regulation; Western Blotting; base; brain-derived growth factor; central nervous system injury; clinically relevant; fetal; gamma-Aminobutyric Acid; improved; in vivo; inhibitor/antagonist; insight; motor function improvement; neurological recovery; neuron apoptosis; neuron loss; neuronal survival; neuroprotection; postnatal; premature; prenatal; prenatal testing; prevent; response; spatiotemporal; symporter; theories; young adult

DESCRIPTION (provided by applicant): Infants who are born very preterm are prone to cognitive delay, behavioral abnormalities, epilepsy and cerebral palsy. Medications and surgery can partially improve motor function and seizure control, but no interventions directly address the most common deficits - cognitive and behavioral problems, even though these impairments pose the biggest obstacles to these children becoming productive adults. Understanding the mechanisms of how early brain injury disrupts cerebral development, and moreover, how interventions restore cerebral function, will guide the indications and timing of promising therapies. Central nervous system (CNS) injury from very preterm birth often results from a global prenatal hypoxic-ischemic (HI) and/or inflammatory insult. Late in gestation subplate neurons guide and refine cerebral cortical circuit development, especially in cortical layer IV. Subplate neurons are essential for initiation of GABAergic inhibition in developing layer IV via spatiotemporal upregulation of the cation-chloride co-transporter KCC2 and maturation of GABAAR subunits. By extruding chloride, increasing KCC2 expression regulates the developmental switch of GABA responses from excitatory to inhibitory, and along with GABAAR maturation, directs effective cortical circuit formation. We hypothesize that CNS injury associated with preterm birth causes premature subplate neuron loss, and thus impairs maturation of cortical layer IV GABAAR subunits and functional KCC2 expression, essential components of cerebral cortical development. Further, we predict that post-injury neuroprotective erythropoietin (EPO) treatment can mitigate compromised cortical development by limiting alterations in GABAAR subunits and KCC2 maturation, and by promoting neurological recovery. Using our clinically-relevant model of prenatal transient systemic hypoxia-ischemia (TSHI) in rodents on embryonic day 18 (E18) that models the global CNS injury associated with very preterm birth in humans, we propose these Aims: 1) to test that premature loss of subplate following prenatal TSHI in rats impairs cerebral cortical maturation in vivo and in slice cultures with mechanical subplate ablation, 2) to test that prenatal TSHI limits KCC2 membrane expression in cortical layer IV via BDNF/calpain-mediated mechanisms, and 3) to test that post-injury neonatal EPO treatment promotes cortical layer IV KCC2 and GABAAR recovery after E18 TSHI in vivo and in vitro. We predict postnatal EPO treatment minimizes premature subplate regression, increases KCC2 expression and restores GABAAR subunit maturation. After prenatal TSHI followed by neonatal EPO or vehicle treatment, cognitive and behavioral function will be tested in young adult rats to test our prediction that EPO can restore cerebral cortical development. Together, these studies will elucidate mechanisms of subplate regulation of early cerebral cortical development following prenatal global HI, and provide insights into how prenatal injury is reversed with delayed EPO treatment, with the goal of improving cognitive and behavioral outcomes after prenatal injury.

描述（由申请人提供）：早产儿容易出现认知延迟、行为异常、癫痫和脑瘫。药物和手术可以部分改善运动功能和癫痫控制，但没有干预措施直接解决最常见的缺陷-认知和行为问题，即使这些障碍对这些儿童成为有生产力的成年人构成最大障碍。了解早期脑损伤如何破坏大脑发育的机制，以及干预措施如何恢复大脑功能，将指导有希望的治疗的适应症和时机。极早产引起的中枢神经系统（CNS）损伤通常是由于产前全面缺氧缺血（HI）和/或炎症损伤。妊娠晚期，亚板神经元引导和完善大脑皮层回路的发育，特别是在皮层IV层。亚板神经元通过时空上调阳离子-氯共转运蛋白KCC 2和GABAAR亚基的成熟，对发育中的IV层GABA能抑制的启动至关重要。通过挤压氯化物，增加KCC 2表达调节GABA反应从兴奋性到抑制性的发育转换，并且沿着GABAAR成熟，指导有效的皮层回路形成。我们推测，早产相关的中枢神经系统损伤导致过早的亚板神经元损失，从而损害成熟的皮层第四层GABAAR亚基和功能性KCC 2的表达，大脑皮层发育的重要组成部分。此外，我们预测，损伤后的神经保护性促红细胞生成素（EPO）治疗可以减轻受损的皮质发育限制GABAAR亚基和KCC 2成熟的改变，并通过促进神经恢复。使用我们在胚胎第18天（E18）的啮齿动物中的产前短暂全身性缺氧缺血（TSHI）的临床相关模型，该模型模拟了与人类极早产相关的全球CNS损伤，我们提出了这些目的：1）为了测试在大鼠中产前TSHI后过早丧失亚板在体内和在具有机械亚板消融的切片培养物中损害大脑皮质成熟，2）测试产前TSHI通过BDNF/钙蛋白酶介导的机制限制皮质层IV中的KCC 2膜表达，和3）测试损伤后新生儿EPO治疗在体内和体外促进E18 TSHI后皮质层IV中的KCC 2和GABAAR恢复。我们预测出生后EPO治疗可最大限度地减少过早的亚板消退，增加KCC 2表达并恢复GABAAR亚基成熟。在产前TSHI后，随后进行新生儿EPO或赋形剂治疗，将在年轻成年大鼠中测试认知和行为功能，以测试我们对EPO可以恢复大脑皮层发育的预测。总之，这些研究将阐明产前全球HI后早期大脑皮质发育的亚板调节机制，并提供有关产前损伤如何通过延迟EPO治疗逆转的见解，目的是改善产前损伤后的认知和行为结果。