Investigating the angiogenic role of Murine Double Minute-2 in contractile muscle cells

研究小鼠 Double Minute-2 在收缩肌细胞中的血管生成作用

• 批准号: RGPIN-2017-05675
• 负责人: BIROT, Olivier
• 金额: $ 2.04万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710164
• 关键词: Investigating; angiogenic; role; Murine; Double

Capillaries are our smallest blood vessels. They are the site of exchanges between blood and cells. In skeletal muscles, capillaries play a crucial role in providing oxygen and nutrients to the active muscle cells. Angiogenesis is the very complex process of formation of new capillaries. Physical exercise is a well-known stimulus for skeletal muscle angiogenesis. One single bout of exercise stimulates the expression of signal molecules that regulate the process of muscle angiogenesis. In particular, these molecules act on endothelial cells, the cells forming the wall of the capillaries. In order to get more capillaries, these cells need to be activated so they can proliferate, migrate, and assembly together into new vessels. If the exercise stimulus is repeated daily over a few weeks, like during prolonged exercise training, new functional capillaries will be formed in skeletal muscle, and the muscle function, especially in response to exercise, will be improved. Research in my laboratory aims to identify and to understand the cellular and molecular mechanisms that regulate angiogenesis in skeletal muscle. With my previous NSERC Discovery Grant, we have demonstrated that a molecule named Murine Minute Double-2 (Mdm2) was a key regulator of muscle angiogenesis during exercise. We have observed that exercise strongly activates Mdm2 in skeletal muscle. At the level of the muscle tissue, we have shown that activated Mdm2 was stimulating the expression of several molecules known to activate endothelial cells during exercise. Using endothelial cell culture in vitro, we have then discovered that activated Mdm2 was strongly stimulating the migration of these cells, which is a crucial step in the assembly of endothelial cells to form new capillaries. This research was conducted at the muscle tissue level and in cultured endothelial cells. In the the research program proposed here, our goal will be to focus on the role that Mdm2 could play on angiogenesis specifically at the level of contractile muscle cells. We think that exercise could stimulate Mdm2 activation in muscle cells, leading to the production and release of signal molecules that will in turn act on the neighbouring endothelial cells to stimulate the formation of new capillaries. This will be achieved through three independent research aims. Aim #1. To characterize in vivo in muscle tissue and in vitro in cultured muscle cells the effect of exercise on Mdm2 and its activated form. Aim #2. To investigate in vitro in cultured muscle cells what is the mechanism of action of Mdm2 and its activated form. Aim #3. To investigate in vivo in muscle tissue, specifically at the level of muscle cells taken into the whole muscle context, what is the mechanism of action of Mdm2 and its activated form. Our research program will provide new knowledge in the field of muscle physiology and Mdm2 biology. It will also contribute to the formation of Highly Qualified Personal in Canada.

毛细血管是我们最小的血管。它们是血液和细胞之间交流的位置。在骨骼肌中，毛细血管在为活性肌肉细胞提供氧气和营养中起着至关重要的作用。血管生成是形成新毛细血管的非常复杂的过程。体育锻炼是骨骼肌血管生成的众所周知的刺激。一次锻炼刺激了调节肌肉血管生成过程的信号分子的表达。特别是，这些分子作用于内皮细胞，形成毛细血管壁的细胞。为了获得更多的毛细血管，需要激活这些细胞，以便它们可以将，迁移和组装在一起成新容器。如果每天在几周内重复运动刺激，例如在长时间的运动训练期间，将在骨骼肌中形成新的功能性毛细血管，并且将改善肌肉功能，尤其是在锻炼方面。 我的实验室研究旨在识别和了解调节骨骼肌血管生成的细胞和分子机制。 借助我以前的NSERC发现赠款，我们证明了一个名为Murine Minute Double-2（MDM2）的分子是运动过程中肌肉血管生成的关键调节剂。我们已经观察到，运动在骨骼肌中强烈激活MDM2。在肌肉组织的水平上，我们表明活化的MDM2刺激了在运动过程中已知会激活内皮细胞的几个分子的表达。然后，我们在体外使用内皮细胞培养物，然后发现活化的MDM2强烈刺激了这些细胞的迁移，这是内皮细胞组装的至关重要的步骤，形成了新的毛细血管。这项研究是在肌肉组织水平和培养的内皮细胞中进行的。在此处提出的研究计划中，我们的目标是关注MDM2在收缩肌肉细胞水平上特别针对血管生成的作用。我们认为运动可以刺激肌肉细胞中的MDM2激活，从而导致信号分子的产生和释放，而信号分子反过来又对邻近的内皮细胞起作用，以刺激新毛细血管的形成。 这将通过三个独立的研究目的来实现。 目标＃1。为了表征肌肉组织中的体内和体外培养的肌肉细胞的体外表征运动对MDM2及其活化形式的影响。 目标＃2。在培养的肌肉细胞中研究体外，MDM2的作用机理及其活化形式是什么。 目标＃3。为了研究肌肉组织中的体内，特别是在整个肌肉环境中的肌肉细胞水平上，MDM2及其活化形式的作用机理是什么？ 我们的研究计划将在肌肉生理学和MDM2生物学领域提供新知识。它还将有助于在加拿大成立高素质的个人。