Mechanogenetics: An Integrated Approach in Muscle Dysfunction

描述（由申请人提供）：心脏性能随年龄增长而下降，并归因于异常基因变化的积累。心脏老化的范例已经假设，这些变化最终扰乱肌细胞硬度和细胞骨架组织，导致收缩和/或舒张功能障碍。然而，理解功能障碍的努力受到至少三个因素的阻碍：1）机械遗传学，即影响机械功能的模型生物体内的遗传变异使得难以识别保守的衰老机制，2）模型生物的几何复杂性，以及3）极其渐进的衰老。我们已经开发了新的方法来测量果蝇的被动和主动力学和生理学，即黑腹果蝇，一个模型系统，在6周内从少年迅速老化到老年。使用这些新的分析方法和果蝇模型的高通量性质，我们将研究基因型变异如何影响心脏衰老，我们还将通过微阵列，qPCR和蛋白质印迹法确定哪些果蝇保守基因是导致这些有害变化的最主要原因。使用靶向分子遗传学，我们将随后评估这些特定基因对年龄相关的肌细胞重塑的影响，例如肌节，肋节和连接蛋白表达的变化，以及它们如何改变相邻腹肌和心管之间的粘附。重要的是，我们还将评估这些基因如何改变苍蝇心脏的生理和功能。与传统模型的衰老数据库进行比较，将确保这些果蝇数据为部分负责与年龄相关的功能障碍的基因提供有意义的预测。这项果蝇研究将首次以高通量方式对快速老化心肌的力学和功能进行体内分析和解剖，还将确定可以改善心血管老化的遗传调节剂和潜在治疗靶点。

DESCRIPTION (provided by applicant): Cardiac performance declines with age and has been attributed to the accumulation of abnormal gene changes. The cardiac aging paradigm has postulated that these changes ultimately perturb myocyte stiffness and cytoskeletal organization leading to systolic and/or diastolic dysfunction. However efforts to understand dysfunction have been stymied by at least three factors: 1) mechanogenetics, i.e. the genetic variation within a model organism affecting mechanical function making it difficult to identify conserved aging mechanisms, 2) geometric complexity of model organisms, and 3) extremely gradual aging. We have developed novel approaches to measure the passive and active mechanics and physiology of fruit flies, i.e. Drosophila melanogaster, a model system that rapidly ages from juvenile to geriatric in 6 weeks. Using these new analysis methods and the high throughput nature of the Drosophila model, we will examine how genotypic variation influences cardiac aging, and we will also identify what mammalian-conserved genes are most responsible for these detrimental changes leading to dysfunction via microarrays, qPCR, and western blotting. Using targeted molecular genetics, we will subsequently assess the influence of these specific genes on age-related myocyte remodeling, e.g. changes in expression of sarcomeric, costameric, and junctional proteins, as well as how they alter adhesion between the adjacent ventral muscle and heart tube. Importantly, we will also assess how these genes alter fly heart physiology and function. Comparison with aging databanks of conventional models will ensure that these Drosophila data provide meaningful predictions for the genes responsible in part for age- related dysfunction. This Drosophila work will provide the first in vivo analysis and dissection of the mechanics and function of rapidly aging myocardium in a high throughput fashion and it will also identify genetic modulators and potential therapeutic targets that could improve cardiovascular aging.