Inhibition of GSK3 beta as potential therapy for DM1

抑制 GSK3 beta 作为 DM1 的潜在疗法

基本信息

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
项目类别：
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&apos 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

项目摘要

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 (DM1) 是一种复杂的神经肌肉疾病，其特征是骨骼肌消瘦、虚弱、肌强直和胰岛素抵抗。 DM1 是由扩展的 RNA CUG 重复引起的通过 RNA 结合蛋白 CUGBP1 和 MBNL1 错误调节 RNA 稳态。治疗方法针对 DM1 降低突变 CUG 重复毒性的方法正在积极开发中；然而，仍然无法治愈 DM1。在这里，我们建议检验糖原合酶的遗传抑制的假设激酶 3b (GSK3b) 可改善 DM1 小鼠模型中的骨骼肌病理学。我们发现突变体 CUG 重复序列增加了骨骼肌活检中的酶活性和 GSK3b 水平 DM1 患者和 DM1 小鼠模型 HSALR 小鼠的骨骼肌。我们证明了用锂（Li）（一种已知的 GSK3b 抑制剂）或 GSK3b 的有效抑制剂治疗 HSALR 小鼠， TDZD-8，减少带内核的纤维数量，增加握力，减少肌强直。这样的 HSALR 小鼠肌肉病理学的改善伴随着 GSK3b 活性的正常化并通过校正 GSK3b 底物之一细胞周期蛋白 D3 的表达。细胞周期蛋白 D3 的校正抑制 GSK3b 会导致 CUGBP1 的抑制形式减少，从而导致骨骼肌萎缩和虚弱。由于这些 GSK3 抑制剂同时减少 GSK3b 和 GSK3a，因此具体目标 1 该提案将检查 HSALR 小鼠中 GSK3b 的遗传减少是否会导致 DM1 的减少肌肉病理学。为了实现 GSK3b 的基因还原，肌肉特异性 GSK3b 敲除 (SbKO) 小鼠与 HSALR 小鼠杂交，产生 HSALR/SbKO 小鼠。改善肌肉病理学 HSALR/SbKO 小鼠将为 DM1 患者治疗的开发提供背景基于 GSK3 的抑制剂。由于 Li 已被 FDA 批准用于治疗情绪疾病，并且由于其有效 GSK3b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会加速使用 GSK3b 抑制剂进行 DM1 疗法的开发。 DM1中GSK3b的增加肌肉表明 GSK3b 的其他底物也可能在 DM1 中发生改变。 DM1 患者有 2 型糖尿病 (T2D) 的易感性。已知患者骨骼肌中 GSK3b 增加与 T2D。 T2D 中 GSK3b 的增加导致糖原合酶活性降低，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 GSK3b 的增加导致葡萄糖和胰岛素不敏感 T2D 易感性。这一假设将在目标 2 中得到检验。总之，我们的研究将表明，如果 GSK3b 的基因抑制可能会改善肌肉病理学并增强胰岛素和葡萄糖的敏感性 DM1 鼠标模型。在 DM1 小鼠模型中获得的知识将转化为临床治疗 DM1。