Mechanogenetics: An Integrated Approach in Muscle Dysfunction

描述(由申请人提供)：心脏功能随着年龄的增长而下降，并被归因于异常基因变化的积累。心脏衰老理论认为，这些变化最终会扰乱心肌细胞僵硬和细胞骨架组织，导致收缩和/或舒张期功能障碍。然而，理解功能障碍的努力至少受到三个因素的阻碍：1)机械遗传学，即模式生物内影响机械功能的遗传变异，使得很难识别保守的衰老机制；2)模式生物的几何复杂性；以及3)极其渐进的衰老。我们开发了新的方法来测量果蝇的被动和主动的力学和生理学，即果蝇，这是一个在6周内从幼年迅速老化到老年的模型系统。利用这些新的分析方法和果蝇模型的高通量性质，我们将研究基因变异如何影响心脏衰老，并通过微阵列、qPCR和Western blotting确定哪些哺乳动物保守的基因对这些导致功能障碍的有害变化最负责任。利用靶向分子遗传学，我们随后将评估这些特定基因对与年龄相关的心肌细胞重塑的影响，例如，肌节蛋白、胞核蛋白和连接蛋白的表达变化，以及它们如何改变相邻腹肌和心管之间的粘连。重要的是，我们还将评估这些基因如何改变果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导致年龄相关功能障碍的基因提供有意义的预测。这项果蝇的工作将首次以高通量的方式对快速老化的心肌的力学和功能进行活体分析和解剖，并将确定可能改善心血管老化的遗传调节剂和潜在的治疗靶点。

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.