Pathogenesis of Myopathy in Models of Myotonic Dystrophy

强直性肌营养不良模型中肌病的发病机制

基本信息

批准号：
7900632
负责人：
CHARLES A THORNTON
金额：
$ 7.36万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-18 至 2010-09-17
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7900632
关键词：
3&apos Untranslated Regions ACTA1 gene Age Alleles Alternative Splicing Apoptosis Biogenesis Biological Assay Breeding Bromodeoxyuridine Calcium Cell Death Cell Nucleus Characteristics Chloride Ion Chlorides Chromatin Chronic Computer Analysis DNA Defect Development Electron Microscopy Electroporation Elements Embryo Employee Strikes Event Exons Fiber Genetic Transcription Growth Factor Human Image Injury Introns Kinetics Knock-out Lead Length Messenger RNA Metabolism Modeling Morphology Mus Muscle Muscle Fibers Myoblasts Myopathy Myotonia Myotonic Disorders Myotonic Dystrophy Natural regeneration Neonatal Nuclear Nuclear Inclusion Pathogenesis Pathway interactions Patients Pattern Physical condensation Physiological Poly(A) Tail Positioning Attribute Predisposition Protein Isoforms Proteins Pump RNA RNA Processing RNA Splicing Regulation Research Personnel Ribonucleases Role Sarcoplasmic Reticulum Skeletal Muscle Symptoms Terminal Repeat Sequences Testing Time Toxic effect Transcript Transgenes Transgenic Mice Transgenic Model Unit of Measure Wild Type Mouse Withdrawal Work cDNA Expression comparative design expression vector fetal gain of function gene induction indexing mouse model mutant myogenesis overexpression postnatal programs repaired research study satellite cell skeletal muscle wasting uptake wasting

项目摘要

DESCRIPTION (provided by applicant): Myotonic dystrophy type 1 [DM1] leads to maldevelopment, myotonia, and wasting of skeletal muscle. DM1 is caused by an unstable CTG repeat expansion in the 3' untranslated region of DMPK. Our central hypothesis is that skeletal muscle findings in DM1 result from a toxic effect of repeat expansion transcripts. Support for this hypothesis comes from studies of HSALR transgenic mice that express CUG expansion RNA in muscle. (CUG)n transcripts accumulate in nuclear foci, leading to a myotonic myopathy that is similar to DM1. Our working model postulates the following sequence of events: expression of CUG expansion RNA -> accumulation of (CUG)n RNA in nuclear foci -> sequestration of muscleblind [Mbnl] proteins in nuclear foci -> abnormal regulation of alternative splicing -> expression of inappropriate splice isoforms -> symptoms of DM. We now have evidence that this model can explain certain aspects of DM1, such as, chloride channelopathy and myotonia. We plan to extend this model and define its limits. First, we will compare patterns of alternative splicing in HSALR, Mbnll knockout, and wild-type mice and test the hypothesis that CUG expansion RNA compromises a specific developmental program of alternative splicing that depends on Mbnl1, the predominant Mbnl protein expressed in muscle. A striking example of aberrant splicing involves Serca1, the calcium re-uptake pump in sarcoplasmic reticulum. The physiologic significance of mis-splicing Serca1 will be determined by calcium imaging. Second, there is little information about metabolism of (CUG)n transcripts. We have derived transgenic mice for inducible expression of CUG expansion transcripts. These mice will be used to compare the accumulation and degradation of transcripts with or without an expanded CUG repeat. We also will test the hypothesis that overexpression of nuclear mRNA-degradases can accelerate clearance of poly-CUG RNA. Third, we will assess myonuclear morphology and bromodeoxyuridine incorporation in HSA(LR) mice to test the hypothesis that accumulation of CUG expansion RNA leads to nuclear demise. In related experiments we will investigate the mechanism of cell death that occurs in HSA(LR) myoblasts when growth factors are withdrawn. Fourth, we have derived transgenic mice with cre-activation alleles to develop models for DM1-related maldevelopment and wasting and test the hypothesis that CUG expansion RNA interferes with muscle differentiation.

描述（由申请人提供）：1型肌发育症[DM1]导致Maldevelverment，Myotonia和骨骼肌浪费。 DM1是由DMPK的3'未翻译区域中不稳定的CTG重复扩展引起的。我们的中心假设是DM1中的骨骼肌发现是由重复膨胀转录物的毒性作用引起的。对这一假设的支持来自对表达肌肉中CUG膨胀RNA的Hsalr转基因小鼠的研究。（CUG）n成绩单积累在核灶中，导致类似于DM1的肌肌病。我们的工作模型假设事件的序列：CUG膨胀RNA的表达RNA - >（CUG）N RNA在核灶中的（cug）N RNA的积累 - >在核局灶性调节中肌肉孔[MBNL]蛋白的序列化 - >异常调节 - >替代性旋转 - >不适当的剪接splice splice spliging->>表达不适当的splice splice spemof splice spemomofemorms>> dm症状的表达。现在，我们有证据表明该模型可以解释DM1的某些方面，例如氯化物通道病和Myotonia。我们计划扩展此模型并定义其限制。首先，我们将比较HSALR，MBNLL敲除和野生型小鼠中替代剪接的模式，并检验以下假设：CUG膨胀RNA损害了替代剪接的特定发展程序，该程序取决于MBNL1，这是MBNL1，这是MBNL蛋白在肌肉中表现出的主要MBNL蛋白。异常剪接的一个惊人例子涉及SERCA1，SERCA1，钙质网中的钙再摄取泵。缩减SERCA1的生理意义将由钙成像确定。其次，关于（CUG）n转录本的代谢的信息很少。我们衍生了转基因小鼠，用于诱导CUG膨胀转录物的诱导表达。这些小鼠将用于比较有或没有扩展的CUG重复的转录本的积累和降解。我们还将检验以下假设：核mRNA降解酶的过表达可以加速对聚盘RNA的清除。第三，我们将评估HSA（LR）小鼠中的肌核形态和溴脱氧尿苷掺入，以检验以下假设：CUG膨胀RNA的积累会导致核死亡。在相关的实验中，我们将研究在撤回生长因子时HSA（LR）成肌细胞中发生的细胞死亡机理。第四，我们衍生出具有CRE激活等位基因的转基因小鼠，以开发与DM1相关的MALDEVEVEMST，浪费和检验的假设，即CUG膨胀RNA会干扰肌肉分化。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Ribonuclear foci at the neuromuscular junction in myotonic dystrophy type 1.

强直性肌营养不良 1 型神经肌肉接头处的核糖核病灶。

DOI：
10.1016/j.nmd.2006.12.015
发表时间：
2007
期刊：
Neuromuscular disorders : NMD
影响因子：
0
作者：
Wheeler,TM;Krym,MC;Thornton,CA
通讯作者：
Thornton,CA

Epigenetic changes and non-coding expanded repeats.

DOI：
10.1016/j.nbd.2010.02.004
发表时间：
2010-07
期刊：
Neurobiology of disease
影响因子：
6.1
作者：
Nakamori M;Thornton C
通讯作者：
Thornton C

Rational design of ligands targeting triplet repeating transcripts that cause RNA dominant disease: application to myotonic muscular dystrophy type 1 and spinocerebellar ataxia type 3.

DOI：
10.1021/ja9020149
发表时间：
2009-07-22
期刊：
Journal of the American Chemical Society
影响因子：
15
作者：
Pushechnikov A;Lee MM;Childs-Disney JL;Sobczak K;French JM;Thornton CA;Disney MD
通讯作者：
Disney MD