The Role of Lipid Rafts in Billirubin Neurotoxicity

脂筏在胆红素神经毒性中的作用

基本信息

批准号：
9112521
负责人：
CYNTHIA FRANCES BEARER
金额：
$ 23.26万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-01 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9112521
关键词：
Abnormal coordination Acute Address Affect Affinity Albumins Apoptosis Basal Ganglia Betaine Bilirubin Binding Biochemical Biological Assay Blood - brain barrier anatomy Brain region Caveolins Cell membrane Cerebellar Diseases Cerebellum Cholesterol Choline Chronic Clinical Crying Cytoplasmic Granules DNA Methylation Data Development Dietary Intervention Equilibrium Experimental Models Exposure to Foundations Functional disorder Funding Ganglioside GM1 Gene Expression Glucuronic Acids Gunn Rats Hearing problem Heme High Prevalence Hyperbilirubinemia In Vitro Injection of therapeutic agent Intervention Kernicterus Knowledge Laminin Lead Lecithin MAPK3 gene Measures Mediating Membrane Microdomains Methionine Mitogen-Activated Protein Kinases Modeling Motor Movement Movement Disorders Neural Cell Adhesion Molecule L1 Neuraxis Neurites Neurodevelopmental Deficit Neurologic Dysfunctions Neurons Neurotoxins Pathway interactions Phospholipids Phototherapy Plasma Play Pregnancy Premature Infant Proteins RNA methylation Rattus Receptor Signaling Reporter Research Role Rotarod Performance Test Seizures Severities Signal Pathway Signal Transduction Signaling Protein Small Interfering RNA Sphingomyelins Sum Symptoms Syndrome Testing Therapeutic Tubulin United States Weight Work acute symptom behavioral outcome brain cell cell type choline supplementation comparative effectiveness equilibration disorder high risk histone methylation in vivo knockout animal neurotoxicity novel persistent symptom postnatal preterm newborn prevent protein protein interaction protein transport public health relevance pup ranpirnase receptor total measurement Bilirubin

项目摘要

DESCRIPTION (provided by applicant): Bilirubin, the breakdown product of heme, is a known neurotoxicant. In the United States, hyperbilirubinemia occurs in almost all preterm neonates <35 weeks gestation. In preterm infants, it is unknown at what level bilirubin causes neurodevelopmental harm. Bilirubin rises to a level where the unconjugated free bilirubin (Bf) concentration exceeds the plasma's capacity to bind it. Then, Bf crosses the blood brain barrier and binds to its targets including the phospholipids of neurons. Once Bf crosses the blood brain barrier, the clinical syndrome of bilirubin-induced neurologic dysfunction can occur. Acute symptoms include high pitched cry, seizures, and hypo- or hypertonicity, whereas chronic symptoms include disturbed movement and balance. Despite the high prevalence of hyperbilirubinemia, the mechanisms underlying the effects of Bf on neuronal function are poorly understood. The affinity of Bf with neuronal phospholipids suggests that lipid rafts might be a major target in hyperbilirubinemia. Lipid rafts are specialized dynamic microdomains of the plasma membrane containing cholesterol as well as the phospholipid sphingomyelin. They promote protein-protein interactions and facilitate signaling and protein trafficking. For example, lipid rafts play a major role on L1 cell adhesion molecule (L1) mediated neurite outgrowth, a crucial step in cerebellar development that depends on both signal transduction and protein trafficking. Our preliminary results show that bilirubin inhibits lipid raft function using L1 as a reporter. In addition, our prior work shows that lipid raft dysfunction can be reduced with supplementation of choline, a precursor of phosphatidylcholine and sphingomyelin. Our novel hypotheses are that 1) free unconjugated bilirubin binds to and causes lipid raft dysfunction, resulting in cerebellar dysfunction; and 2) supplementation with choline will reduce these effects. We will address these hypotheses using both the well established model of cultured cerebellar granule neurons from postnatal day 6 heterozygous Gunn rat pups and the sulfadimethoxine treated homozygous Gunn rat as an in vivo rat pup model. We will use L1, the GABAA receptor, β III tubulin, flotilin and caveolin as reporter proteins to test lipid raft functon in cerebellar granule neurons (CGN) in vitro and in Gunn rat pups in vivo, determine cerebellar weight and test behavioral outcomes: both the constant and accelerating rotarod test. We will test our hypotheses using two specific aims: The first aim will determine if bilirubin accumulates within lipid rafts and its effects on functions of lipid rafts and apoptosis. The effect of choline supplementation on these effects of bilirubin will be determined. In the second aim, the effect of bilirubin on cerebellar weight and cerebellar function will be measured, and the effect of pretreatment with choline determined.

描述（由适用提供）：血红素的分解产物胆红素是已知的神经毒性。在美国，几乎所有早产新生儿都发生了高胆红素，妊娠35周。在早产儿中，未知胆红素在哪种水平上造成神经发育伤害。胆红素升至未偶联的游离胆红素（BF）浓度超过血浆结合其结合的能力的水平。然后，BF越过血脑屏障并与其靶标结合，包括神经元的磷脂。 BF越过血脑屏障后，可能会发生胆红素诱导的神经功能障碍的临床综合征。急性症状包括高高的哭泣，癫痫发作和低渗性或低渗性，而慢性症状包括运动和平衡。尽管高胆红素血症的患病率很高，但对BF影响神经元功能的影响的机制知之甚少。 BF与神经元磷脂的亲和力表明，脂质筏可能是高胆红素血症的主要靶点。脂质筏是含有胆固醇和磷脂鞘磷脂的质膜的专门动态微区。它们促进蛋白质 - 蛋白质相互作用，并促进信号传导和蛋白质运输。例如，脂质筏在L1细胞粘附分子（L1）介导的神经元出现中起着主要作用，这是小脑发育的关键步骤，依赖于信号转导和蛋白质运输。我们的初步结果表明，胆红素使用L1作为A抑制脂质筏功能记者。此外，我们先前的工作表明，脂质筏功能障碍可以通过补充胆碱和磷脂酰胆碱和鞘磷脂的前体来降低。我们的新假设是1）游离未结合的胆红素与脂质筏功能障碍结合并导致小脑功能障碍； 2）补充胆碱将减少这些影响。我们将使用从产后第6天的杂合子Gunn大鼠幼崽和磺胺二甲基氧化剂处理的纯合子Gunn大鼠作为体内大鼠幼崽模型的培养小脑颗粒神经元的良好模型来解决这些假设。我们将使用L1，GABAA受体，βIII微管蛋白，氟替林和小窝蛋白作为报告蛋白来测试脂质筏在小脑颗粒神经元（CGN）的体外和gunn大鼠幼犬中在体内的脂质蛋白质功能，确定Cerebellar的体重和测试行为均不变：不断的行为：我们将使用两个特定目的测试我们的假设：第一个目标将确定胆红素是否在脂质筏中积累及其对脂质筏功能和凋亡功能的影响。胆碱的作用将确定对胆红素这些影响的补充。在第二个目标中，将测量胆红素对小脑重量和小脑功能的影响，并确定胆碱预处理的影响。