CNS in Congenital DM1: Pathogenesis and Therapeutic Opportunities

先天性 DM1 中的中枢神经系统：发病机制和治疗机会

• 批准号: 10553142
• 负责人: LUBOV T TIMCHENKO
• 金额: $ 35.56万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10553142
• 关键词: Adult; Affect; Aftercare; Age; Age Months; Anxiety; Brain; CDK4 gene; CUG repeat; Central Nervous System; Clinical Research; Clinical Trials; Complex; Congenital Myotonic Dystrophy; Defect; Development; Disease; Event; Family; Functional disorder; Genes; Growth; Heart; Human; Knock-in; Knowledge; Long-Term Effects; Messenger RNA; Modeling; Molecular; Motor; Mus; Muscle; Muscle Fibers; Mutate; Myoblasts; Myotonic dystrophy type 1; Nervous System Physiology; Organ; Pathogenesis; Pathology; Pathway interactions; Patients; Phase; Phenotype; Phosphorylation; Phosphotransferases; Proteins; RNA Splicing; RNA metabolism; RNA-Binding Proteins; Role; Severities; Signal Pathway; Site; Skeletal Muscle; Stress; Survival Rate; System; Testing; Therapeutic; Therapeutic Effect; Tissues; Translations; Work; biopharmaceutical industry; cognitive function; cyclin D3; disability; drug candidate; drug development; improved; inhibitor; mRNA Translation; mouse model; mutant; pediatric patients; postnatal; prenatal; stress granule; transcriptome

Myotonic Dystrophy type 1 (DM1) is a complex disease affecting many organs including skeletal muscle and the Central Nervous System (CNS). The majority of mechanistic studies in the DM1 field have been focused on muscle and very little is known about the molecular pathogenesis of CNS dysfunction in DM1. DM1 is caused by the expanded CUG repeats which misregulate RNA-binding proteins of two families, MBNL and CUGBP (CELF). Proteins of both families are expressed in many tissues, including the CNS. CUGBP1 activity is regulated by GSK3-cyclin D3-CDK4 dependent phosphorylation. In DM1, CUG repeats reduce phosphorylation of CUGBP1 at S302 via increase of GSK3 kinase, thereby converting active CUGBP1 into inactive un-pS302-CUGBP1 (termed CUGBP1 repressor or CUGBP1REP) because it blocks translation of mRNAs in Stress Granules. We found that GSK3 is increased in the brains of congenital DM1 (CDM1) mice (DMSXL model). CUGBP1REP is also elevated in the brains of DMSXL mice. The prenatal treatment of DMSXL mice with the inhibitor of GSK3, tideglusib (TG), increases survival rate of underdeveloped DMSXL mice, improves their growth and strength and reduces their anxiety. These findings suggest that the inhibitors of GSK3 are good candidate drugs to reduce CNS defects in CDM1 via correction of GSK3-CUGBP1REP pathway in brain. In support of this hypothesis, recent Phase IIa clinical trial for adult CDM1 showed that TG has beneficial effect on cognitive function in patients with CDM1. Since GSK3 has many substrates in brain, the inhibitors of GSK3 might affect many pathways. This project will determine the contribution of the GSK3-CUGBP1REP pathway in CNS pathogenesis of CDM1 (Aim 1). We will address this question by analysis of DMSXL mice crossed with a new mouse model in which the GSK3-cyclin D3-CDK4 site of CUGBP1 (S302) is mutated (S302A knock in model). The molecular pathways disrupted by the mutant DMPK mRNA in the brains of DMSXL mice will be compared to those disrupted by CUGBP1REP in the brains of S302A mice. We found that the inhibitor of GSK3, TG, reduces the mutant DMPK mRNA in skeletal muscle cell precursors from patients with CDM1, correcting splicing events in myoblasts. To determine if TG has the same function in CNS of CDM1, we will test if TG reduces the mutant DMPK mRNA in the brains of DMSXL mice, normalizing splicing of brain-specific mRNAs (Aim 2). Positive long-term effect of the prenatal treatment of DMSXL mice with TG suggests that early correction of GSK3 in CDM1 is critical for the improved development of CDM1 patients. Aim 3 of the project will test if short postnatal treatments with TG have a long-term positive effect on phenotype of DMSXL mice. The therapeutic effect of TG will be also examined in DMSXL mice, treated at young age and in adulthood. The knowledge generated is critical for the development of the GSK3 based therapies of CNS dysfunction in CDM1.

肌发育症1型（DM1）是一种复杂的疾病，影响了许多器官，包括骨骼肌肉和 DM1场中的大多数机械研究都集中在肌肉上，并且对DM1中CNS功能障碍的分子发病机理知之甚少。 DM1是由扩展的cug重复序列引起的，该重复量未经调节两个家族的RNA结合蛋白，即MBNL和CUGBP（CELF）。两个家族的蛋白质在包括中枢神经系统在内的许多组织中表达。 CUGBP1活性受GSK3-CYCLIN D3-CDK4依赖性磷酸化调节。在DM1中，CUG重复序列通过增加GSK3激酶在S302时降低CUGBP1的磷酸化，从而将活动的CUGBP1转化为无活性的UN-PS302-CUGBP1（称为CUGBP1复制剂或CUGBP1REP），因为它阻止了压力固定剂中MRNAS中MRNA的转换。我们发现，先天性DM1（CDM1）小鼠（DMSXL模型）的大脑中GSK3增加。 DMSXL小鼠的大脑中的CUGBP1REP也升高。用GSK3，Tideglusib（TG）的抑制剂对DMSXL小鼠的产前治疗增加了欠发达DMSXL小鼠的存活率，改善了它们的生长和力量并减轻了焦虑。这些发现表明，GSK3的抑制剂是通过校正GSK3-CUGBP1REP途径来减少CDM1中CNS缺陷的良好候选药物。为了支持这一假设，最近针对成年CDM1的IIA期临床试验表明，TG对CDM1患者的认知功能具有有益作用。由于GSK3在大脑中有许多底物，因此GSK3的抑制剂可能会影响许多途径。该项目将确定CDM1发病机理中GSK3-CUGBP1REP途径的贡献（AIM 1）。我们将通过分析与新的小鼠模型交叉的DMSXL小鼠的分析，其中CUGBP1的GSK3-CYCLIN D3-CDK4位点（S302）被突变（模型中的S302A敲击）。将DMSXL小鼠大脑中突变的DMPK mRNA破坏的分子途径将与S302A小鼠大脑中CUGBP1REP残疾的分子途径进行比较。我们发现GSK3，TG的抑制剂可降低CDM1患者骨骼肌细胞前体中突变的DMPK mRNA，从而纠正成肌细胞中的剪接事件。为了确定TG在CDM1的CNS中是否具有相同的功能，我们将测试TG是否降低了DMSXL小鼠大脑中的突变型DMPK mRNA，从而使脑特异性mRNA的剪接正常化（AIM 2）。用TG对DMSXL小鼠进行产前治疗的长期阳性作用表明，CDM1中GSK3的早期校正对于改善CDM1患者的发育至关重要。该项目的AIM 3将测试是否对TG的短期后治疗对DMSXL小鼠的表型具有长期积极影响。 TG的理论效应还将在DMSXL小鼠中进行检查，该小鼠在年轻时和成年期接受。产生的知识对于CDM1中CNS功能障碍的基于GSK3的疗法的开发至关重要。