Characterisation of skeletal development and the use of anabolic agents in murine models of Duchenne muscular dystrophy

杜氏肌营养不良症小鼠模型中骨骼发育的特征和合成代谢药物的使用

• 批准号: MR/N020588/1
• 负责人: Claire Wood
• 金额: $ 36.29万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FN020588%2F1
• 关键词: Characterisation; skeletal; development; use; anabolic

Duchenne muscular dystrophy (DMD) is a severe and ultimately fatal disease. It affects up to 1 in 4000 males and there is no cure. Steroids are the only treatment that can help slow down muscle weakness but they have many side effects including growth failure and osteoporosis. It is unclear exactly why, but even boys who are not treated with steroids tend to be short and have weak bones. We do not know whether the bone and growth problems are just caused by the muscle weakness (our bones need to be 'loaded' by muscle activity in order to strengthen and grow efficiently), or whether there is another primary problem. It may be that because DMD is a chronic inflammatory process, this disrupts the growth hormone (GH)/insulin-like growth factor (IGF-1) pathway. Growth hormone is produced by the anterior pituitary gland. It can act directly on the skeleton, but mainly acts indirectly, through IGF-1. Together the GH/IGF-1 pathway plays a crucial role in regulating normal bone growth and bone mass during childhood, and children with either GH or IGF-1 deficiency are short and have osteoporosis. There are no treatments available to help bone growth in DMD. We will investigate the role of GH and IGF-1 in bone and growth of mice models of DMD. The mouse model commonly used in DMD is the X-linked Muscular Dystrophy (mdx) mouse, but it has significant limitations because the disease process is not as severe and muscle regeneration occurs in the mdx mice, unlike in patients with Duchenne. Very few medications that are effective in the mdx mouse have shown to be useful in patients. Therefore we will use a new mouse model, the Cmah-/-mdx mouse. This mouse is bred from the mdx mouse, but also has an additional gene deletion to make it more 'human' and therefore we hope will behave in more similar way to patients with Duchenne. I will look, for the first time, at bone and growth in the Cmah-/-mdx and compare it to the mdx and a healthy 'wildtype' mouse. I will then give the mice steroids to determine the effects on their growth and skeleton. I will also see if the Cmah-/mdx mouse responds to GH and IGF-1, both alone and in combination. To do this I will use a range of techniques, including micro CT and labeling of the bones and growth plate to monitor the rate of growth. I will also culture metatarsals (feet) bones from the embryos of these mice models to see if they also display reduced growth and bone fragility. If they do this will show us that there is a primary problem relating to the skeleton in addition to the problems caused by steroids and muscle weakness. This work is very important because both GH and IGF-1 are readily available and are already used in children. If they are found to help bone development and encourage growth, either alone or acting together, in mice models, then this work could be carried out as a clinical trial in patients with DMD. It is also important to further describe the new Cmah-/-mdx mouse model, so that it can be used in other DMD experiments. The data that we collect may also help in the design of new therapies that are directed specifically at the mechanism of the problem that leads to poor bone health and growth in DMD.

Duchenne肌营养不良症(DMD)是一种严重且最终致命的疾病。每4000名男性中就有1人感染这种疾病，而且目前还没有治愈方法。类固醇是唯一可以帮助减缓肌肉无力的治疗方法，但它们有许多副作用，包括生长障碍和骨质疏松。具体原因尚不清楚，但即使是没有接受类固醇治疗的男孩也往往身材矮小，骨骼脆弱。我们不知道骨骼和生长问题是否只是由肌肉无力引起的(我们的骨骼需要通过肌肉活动来加强和高效生长)，或者是否存在另一个主要问题。这可能是因为DMD是一个慢性炎症过程，这扰乱了生长激素(GH)/胰岛素样生长因子(IGF-1)途径。生长激素是由脑下垂体分泌的。它可以直接作用于骨骼，但主要通过IGF-1间接作用。总之，GH/IGF-1途径在调节儿童时期正常的骨生长和骨量方面起着至关重要的作用，GH或IGF-1缺乏的儿童身材矮小，患有骨质疏松症。目前还没有有效的治疗方法来帮助DMD患者的骨骼生长。我们将探讨GH和IGF-1在DMD模型小鼠骨骼和生长发育中的作用。DMD常用的小鼠模型是X-连锁肌肉营养不良(MDX)小鼠，但它有很大的局限性，因为疾病过程不像Duchenne患者那样严重，并且MDX小鼠的肌肉再生发生。在MDX小鼠身上有效的药物很少被证明对患者有用。因此，我们将使用一种新的鼠标模型，cmah-/-mdx小鼠。这只小鼠是从MDX小鼠培育而来的，但也有一个额外的基因缺失，使它更具人性化，因此我们希望它的行为方式将更类似于Duchenne患者。我将第一次观察Cmah-/-MDX的骨骼和生长情况，并将其与MDX和一只健康的野生型小鼠进行比较。然后，我会给小鼠服用类固醇，以确定对它们生长和骨骼的影响。我还会看看cmah-/mdx小鼠是否对GH和IGF-1有反应，无论是单独的还是联合的。为了做到这一点，我将使用一系列技术，包括微型CT以及骨骼和生长板的标记来监测生长速度。我还将从这些小鼠模型的胚胎中培养跖骨(脚)骨，看看它们是否也显示出生长减慢和骨骼脆性。如果他们这样做，这将向我们表明，除了类固醇和肌肉无力造成的问题外，还有一个与骨骼有关的主要问题。这项工作非常重要，因为GH和IGF-1都很容易获得，并且已经在儿童中使用。如果在小鼠模型中发现它们单独或共同作用有助于骨骼发育和促进生长，那么这项工作可以作为DMD患者的临床试验进行。进一步描述新的CmaH-/-MDX小鼠模型也很重要，以便它可以用于其他DMD实验。我们收集的数据也可能有助于设计新的治疗方法，专门针对导致DMD骨骼健康和生长不良的问题的机制。

项目成果

The oral splicing modifier RG7800 increases full length survival of motor neuron 2 mRNA and survival of motor neuron protein: Results from trials in healthy adults and patients with spinal muscular atrophy

口服剪接修饰剂 RG7800 提高了运动神经元 2 mRNA 的全长存活率和运动神经元蛋白的存活率：在健康成人和脊髓性肌萎缩症患者中进行的试验结果

• DOI: 10.1016/j.nmd.2018.10.001
• 发表时间: 2019
• 期刊: Neuromuscular Disorders
• 影响因子: 2.8
• 作者: Kletzl H

Nusinersen versus Sham Control in Infantile-Onset Spinal Muscular Atrophy

• DOI: 10.1056/nejmoa1702752
• 发表时间: 2017-11-02
• 期刊: NEW ENGLAND JOURNAL OF MEDICINE
• 影响因子: 158.5
• 作者: Finkel, R. S.;Mercuri, E.;De Vivo, D. C.
• 通讯作者: De Vivo, D. C.

Metabolic outcomes in very low birthweight and preterm infants in later life.

极低出生体重和早产儿晚年的代谢结果。

• DOI: 10.1016/j.jped.2018.06.002
• 发表时间: 2019
• 期刊: Jornal de pediatria
• 影响因子: 3.3
• 作者: Embleton ND

Preterm birth and the timing of puberty: a systematic review.

• DOI: 10.1186/s12887-017-0976-8
• 发表时间: 2018-01-08
• 期刊: BMC pediatrics
• 影响因子: 2.4
• 作者: James E;Wood CL;Nair H;Williams TC
• 通讯作者: Williams TC

Measurement of salivary testosterone in adolescents and young men with Duchenne muscular dystrophy

患有杜氏肌营养不良症的青少年和年轻男性唾液睾酮的测量

• DOI: 10.21203/rs.3.rs-26210/v1
• 发表时间: 2020
• 作者: Sahun Y