Genetic Control of Phospholipid Biosynthesis and Muscular Dystrophy

磷脂生物合成和肌营养不良症的遗传控制

基本信息

批准号：
7498940
负责人：
GREGORY A. COX
金额：
$ 34.99万
依托单位：
JACKSON LABORATORY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-09-14 至 2012-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7498940
关键词：
22q13.3 Adult Affect Alleles Anabolism Birth Brazil Candidate Disease Gene Cells Cessation of life Choline Choline Kinase Choline-Phosphate Cytidylyltransferase Clinical Collaborations DNA Defect Disease Disease Progression Electron Transport Enzymes Eukaryotic Cell Family Forelimb Foundations Genes Genetic Goals Hindlimb Histopathology Human Japan Lead Lecithin Limb-Girdle Muscular Dystrophies Link Lipids Localized Maintenance Membrane Membrane Potentials Membrane Proteins Merosin Mitochondria Molecular Molecular Genetics Mus Muscle Muscle Weakness Muscular Dystrophies Mutant Strains Mice Mutation Myoblasts Nature Nuclear Envelope Pathway interactions Patients Phenotype Phospholipids Phosphorylation Phosphorylcholine Physiology Population Process Proteins Range Sampling Sarcolemma Severities Skeletal Muscle Testing Tissues Transgenic Mice Universities cohort congenital muscular dystrophy disability disease phenotype gait examination genetic linkage human disease in vivo mitochondrial dysfunction mitochondrial membrane muscle transplantation mutant novel null mutation protein function wasting

项目摘要

DESCRIPTION (provided by applicant): Muscular dystrophies include a diverse group of genetically heterogeneous disorders that affect 1:2000 births worldwide. The diseases are characterized by progressive muscle weakness and wasting that lead to severe disability and often premature death. Rostrocaudal muscular dystrophy (rmd) is a new recessive mouse mutation causing a progressive muscular dystrophy with a rostral-to-caudal gradient of severity. We have identified the rmd mutation as a 1.6 kb deletion within the choline kinase beta (Chkb) gene, resulting in loss of CHKB protein and enzymatic activity. CHKB is one of two mammalian choline kinase (CHK) enzymes catalyzing the phosphorylation of choline to phosphocholine in the biosynthesis of the major membrane phospholipid phosphatidylcholine (PC). PC is the most abundant phospholipid in eukaryotic cells and it serves not only as a structural foundation for membrane bilayers, but also as a precursor for several lipid messengers. While mutant rmd mice show dramatically decreased CHK activity in all tissues examined, the disease is only evident in skeletal muscle tissues which display a 30% reduction in total PC content. Several muscular dystrophy mutations have been identified in membrane-associated proteins that function at the sarcolemma or nuclear envelope. However, the rmd mutant mouse is the first to demonstrate that alterations in membrane phospholipid composition can result in a progressive muscular dystrophy phenotype. The aims of our proposal are: 1) To test the hypothesis that rmd muscular dystrophy is due to a cell autonomous loss of CHKB in skeletal muscles. 2) To test the hypothesis that mitochondrial dysfunction underlies the progressive skeletal muscle degeneration in primary mouse myoblast cultures and adult skeletal muscles. 3) To screen a large Brazilian population of congenital muscular dystrophy (CMD) and limb-girdle muscular dystrophy (LGMD) patients for mutations in the orthologous human CHKB gene. In collaboration with Dr. Mayana Zatz, we will test for human CHKB mutations in DNA samples from patients that have previously been screened and eliminated for known molecular causes of muscular dystrophy. The primary goals of this proposal are to use the novel mouse rmd mutation to explore the cell-autonomous nature of this defect in skeletal muscles, to dissect the molecular and genetic mechanisms of muscular degeneration and to determine the range of defects in CHKB that underlie previously unidentified human muscular dystrophies. The rmd mouse offers the first demonstration of a defect in a phospholipid biosynthetic enzyme causing muscular dystrophy and may reveal unique entry points in which to intervene in the disease process.

描述（由申请人提供）：肌肉营养不良包括影响全世界1：2000出生的一组遗传异质性疾病。这些疾病的特征是进行性肌肉无力和浪费导致严重的残疾和常常过早死亡。 tho骨肌肉营养不良（RMD）是一种新的隐性小鼠突变，导致肌肉发达症具有严重程度的延髓至辅助梯度。我们已经将RMD突变确定为胆碱激酶β（CHKB）基因内的1.6 kb缺失，从而导致CHKB蛋白和酶促活性的损失。 CHKB是两种哺乳动物胆碱激酶（CHK）酶之一，在主要膜磷脂磷脂酰胆碱（PC）的生物合成中催化胆碱对磷酸的磷酸化。 PC是真核细胞中最丰富的磷脂，它不仅是膜双层的结构基础，而且还可以作为几个脂质使者的前体。尽管突变的RMD小鼠在所有检查的组织中表现出急剧降低的CHK活性，但该疾病仅在骨骼肌组织中很明显，这些疾病的总PC含量降低了30％。已经在肌膜或核包膜上起作用的膜相关蛋白质中鉴定出了几种肌肉营养不良突变。然而，RMD突变小鼠是第一个证明膜磷脂组成的改变会导致进行性肌肉营养不良的表型。我们提案的目的是：1）检验RMD肌肉营养不良的假设是由于细胞自主损失CHKB在骨骼肌中的自主损失。 2）测试线粒体功能障碍的假设是原代小鼠成肌细胞培养物和成年骨骼肌的进行性骨骼肌变性的基础。 3）筛选大量巴西先天性肌肉营养不良（CMD）和肢体肌营养不良症（LGMD）患者的大量人群，以筛选直系同源的人CHKB基因中的突变。通过与玛雅娜·扎兹（Mayana Zatz）博士合作，我们将测试来自以前已筛查并消除的患者的DNA样品中的人CHKB突变，这些突变因已知的肌营养不良症的已知分子原因。该提案的主要目标是使用新型的小鼠RMD突变来探索骨骼肌中这种缺陷的细胞自治性质，以剖析肌肉变性的分子和遗传机制，并确定CHKB缺陷的范围，而CHKB的缺陷范围是先前未鉴定的人类肌肉肌肉疾病的基础。 RMD小鼠在磷脂生物合成酶中首次证明了缺陷，从而引起肌肉营养不良，并可能揭示出介入疾病过程的独特入口点。