Inhibition of GSK3 beta as potential therapy for DM1

抑制 GSK3 beta 作为 DM1 的潜在疗法

• 批准号: 8635126
• 负责人: LUBOV T TIMCHENKO
• 金额: $ 17.16万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-20 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8635126
• 关键词: 19q; 3' Untranslated Regions; Affect; Basic Science; Biopsy; Breeding; Cardiac; Cataract; Cell Nucleus; Cells; Chromosomes; Clinical; Complex; Cytoplasmic Granules; Data; Defect; Development; Diabetes Mellitus; Disease; FDA approved; Fasting; Fatigue; Fiber; Fibrosis; Functional disorder; Genes; Genetic; Genetic Translation; Glucose; Glucose Intolerance; Glycogen; Glycogen (Starch) Synthase; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Histopathology; Homeostasis; Inflammation; Insulin; Insulin Resistance; Knock-in Mouse; Knock-out; Knowledge; Lead; Left; Lithium; Messenger RNA; Modeling; Moods; Mus; Muscle; Muscle Cells; Muscle Proteins; Muscle Weakness; Muscular Atrophy; Myopathy; Myotonia; Myotonic Dystrophy; Neurologic; Neuromuscular Diseases; Non-Insulin-Dependent Diabetes Mellitus; Pathology; Pathway interactions; Patients; Phosphorylation; Phosphotransferases; Predisposition; Prevalence; Production; Protein Biosynthesis; RNA; RNA Processing; RNA Splicing; RNA-Binding Proteins; Role; Skeletal Muscle; Stress; Testing; Therapeutic; Therapeutic Intervention; Toxic effect; Transgenic Mice; Translating; aged; base; blood glucose regulation; cyclin D3; feeding; glucose metabolism; glucose tolerance; grasp; high risk; improved; inhibitor/antagonist; insulin sensitivity; insulin tolerance; mouse model; muscle strength; mutant; preclinical study; public health relevance; skeletal muscle wasting; therapy development; wasting

Myotonic Dystrophy type 1 (DM1) is a complex neuromuscular disease characterized by skeletal muscle wasting, weakness, myotonia and insulin resistance. DM1 is caused by the expanded RNA CUG repeats that misregulate RNA homeostasis through RNA-binding proteins, CUGBP1 and MBNL1. Therapeutic approaches for DM1 reducing toxicity of the mutant CUG repeats are actively developing; however, there is still no cure for DM1. Here we propose to examine the hypothesis that the genetic inhibition of Glycogen Synthase kinase 3b (GSK3b) improves skeletal muscle pathology in the DM1 mouse model. We found that the mutant CUG repeats increase enzymatic activity and the levels of GSK3b in skeletal muscle biopsies from patients with DM1 and in skeletal muscle of the DM1 mouse model, HSALR mice. We showed that the treatments of HSALR mice with lithium (Li), a known inhibitor of GSK3b, or with the potent inhibitor of GSK3b, TDZD-8, reduce the number of fibers with internal nuclei, increase grip strength and reduce myotonia. Such improvement of muscle pathology in the HSALR mice was accompanied by the normalization of GSK3b activity and by correction of expression of one of the GSK3b substrates, cyclin D3. The correction of cyclin D3 by the inhibition of GSK3b leads to the reduction of the suppressive form of CUGBP1, which causes skeletal muscle atrophy and weakness. Since these GSK3 inhibitors reduce both GSK3b and GSK3a, Specific Aim 1 of this proposal will examine if a genetic reduction of GSK3b in HSALR mice will lead to the reduction of DM1 muscle pathology. To achieve the genetic reduction of GSK3b, muscle specific GSK3b knock out (SbKO) mice are crossed with HSALR mice, producing HSALR/SbKO mice. Improvement of muscle pathology in HSALR/SbKO mice will provide a background for the development of therapy for DM1 patients which will be based on the inhibitors of GSK3. Since Li is approved by FDA to treat mood diseases and because potent inhibitors of GSK3b are used in the pre-clinical studies for other diseases, the application of these inhibitors might accelerate the development of DM1 therapy using GSK3b inhibitors. The increase of GSK3b in DM1 muscle suggests that other substrates of GSK3b might be also altered in DM1. Patients with DM1 have a predisposition to Type 2 Diabetes (T2D). It is known, that GSK3b is increased in skeletal muscle of patients with T2D. The increase of GSK3b in T2D causes a reduction of the activity of glycogen synthase that leads to the reduction of the glycogen synthesis and alteration of glucose metabolism. We hypothesize that the increase of GSK3b in skeletal muscle of HSALR mice causes glucose and insulin insensitivity and predisposition to T2D. This hypothesis will be tested in the Aim 2. In summary, our study will show if the genetic inhibition of GSK3b might improve muscle pathology and enhance insulin and glucose sensitivity in the DM1 mouse model. The knowledge, obtained in mouse model of DM1, will be translated to the clinical therapy of DM1.

强直性肌营养不良1型（DM 1）是一种以骨骼肌为特征的复杂神经肌肉疾病 消瘦、虚弱、肌强直和胰岛素抵抗。DM 1是由扩增的RNA CUG重复序列引起的， 通过RNA结合蛋白CUGBP 1和MBNL 1错误调节RNA稳态。治疗方法 对于DM 1，减少突变CUG重复的毒性正在积极开发;然而，仍然没有治愈DM 1的方法。 DM1。在这里，我们建议检查的假设，遗传抑制糖原合成酶 激酶3b（GSK 3b）改善DM 1小鼠模型中的骨骼肌病理。我们发现 突变的CUG重复序列增加了骨骼肌活检组织中的酶活性和GSK 3b水平， DM 1患者和DM 1小鼠模型、HSALR小鼠的骨骼肌中。我们证明了 用锂（Li）（一种已知的GSK 3b抑制剂）或用有效的GSK 3b抑制剂治疗HSALR小鼠， TDZD-8，减少具有内部核的纤维的数量，增加握力并减轻肌强直。等 HSALR小鼠肌肉病理学的改善伴随着GSK 3b活性的正常化 并通过纠正GSK 3b底物之一细胞周期蛋白D3的表达。细胞周期蛋白D3的校正 GSK 3b的抑制导致CUGBP 1的抑制性形式的减少，这导致骨骼肌 萎缩和虚弱。由于这些GSK 3抑制剂减少GSK 3b和GSK 3a两者，因此本发明的具体目的1 一项提案将研究HSALR小鼠中GSK 3b的遗传减少是否会导致DM 1的减少。 肌肉病理学为了实现GSK 3b的遗传减少，肌肉特异性GSK 3b敲除（SbKO） 小鼠与HSALR小鼠杂交，产生HSALR/SbKO小鼠。肌肉病理学的改善， HSALR/SbKO小鼠将为DM 1患者的治疗开发提供背景， 基于GSK 3的抑制剂。由于Li被FDA批准用于治疗情绪疾病， GSK 3b抑制剂用于其他疾病的临床前研究，这些抑制剂的应用 可能加速使用GSK 3b抑制剂的DM 1治疗的发展。DM 1中GSK 3b的增加 肌肉中的GSK 3b的其他底物也可能在DM 1中改变。1型糖尿病患者 易患2型糖尿病（T2 D）。已知GSK 3b在患者的骨骼肌中增加， 关于T2 D T2 D中GSK 3b的增加导致糖原合酶活性的降低，从而导致 糖原合成的减少和葡萄糖代谢的改变。我们假设 HSALR小鼠骨骼肌中GSK 3b的增加导致葡萄糖和胰岛素不敏感性， 易患T2 D。这一假设将在目标2中得到检验。总之，我们的研究将表明， GSK 3b的基因抑制可能改善肌肉病理学，并增强胰岛素和葡萄糖敏感性， DM 1小鼠模型。在DM 1小鼠模型中获得的知识将被转化为临床治疗 的DM 1。