Mechanogenetics: An Integrated Approach to Aging in Muscle Dysfunction

项目摘要 心脏功能随着年龄的增长而下降，但人群中的遗传变异使得难以识别心脏功能。 保守的老化机制对机械功能产生负面影响，即机械遗传学。过去 5年来，我们研究了快速衰老的果蝇的心脏功能， 实验室果蝇品系。我们发现果蝇的黏着斑蛋白随年龄增长而增加， 调节用它来加强和加固他们的costameres和闰盘，这有助于维持 它们的肌节晶格的结晶度和改善收缩性。在心肌细胞水平，维持间- 肌丝间距与肌壁缩短速度和缩短分数相关，在全身范围内， 寿命具有降低的基底膜（BM）蛋白质表达（例如层粘连蛋白）的蝇株也表现出低表达。 类似的全身益处，但由于细胞外基质更薄，这改善了细胞间的细胞偶联， 重要的是，随着年龄的增长，黏着斑蛋白上调和BM下调 在非人类灵长类动物中得以保存。这些数据共同提出了一种新的内-外老化模式 心脏功能，即一个强大的内部收缩装置与有限的细胞外连接， BM。在这项拨款申请中，我们提出了进一步的目标，以确定这些细胞内和细胞外 心脏扰动联合作用以改变细胞、组织和器官水平的功能。初步 对转基因果蝇品系的评估表明，更有效的心肌细胞收缩， 底物利用和氧消耗，以及随后的器官灌注和全身 新陈代谢和更好的健康和寿命。鉴于这种模式和机械遗传学所面临的挑战， 目前，我们已经开发了新的生物和分析工具，这将提高可行性， 评估野生型和转基因果蝇心肌与年龄相关的机械差异 线因此，这项正在进行的工作将继续提高我们对内外老化的理解 范例

Project Summary Cardiac performance declines with age, but genetic variation within a population makes it difficult to identify the conserved aging mechanisms that negatively impact mechanical function, i.e. mechanogenetics. Over the past 5 years, we have studied cardiac function of the rapidly aging Drosophila melanogaster across many laboratory fruit fly strains. We found that fly strains with age-dependent and heart-specific vinculin up- regulation use it to reinforce and stiffen their costameres and intercalated discs, which helps maintain the crystallinity of their sarcomere lattice and improves contractility. At the cardiomyocyte level, maintaining inter- myofilament spacing prolongs wall shortening velocity and fractional shortening, and systemically, it extends lifespan. Fly strains with decreased basement membrane (BM) protein expression, e.g. laminin, also exhibit similar systemic benefits but due to thinner extracellular matrix, which improves cell-cell coupling between adjacent myocyte layers; importantly, both vinculin up-regulation and BM down-regulation with age appear conserved up through non-human primates. Together these data suggest a new inside-outside aging paradigm that prolongs heart function, i.e. a robust internal contractile apparatus with limited extracellular connections to BM. In this grant application, we propose further aims to determine how these intracellular and extracellular heart perturbations act combinatorially to alter function across cellular-, tissue-, and organ-levels. Preliminary assessments in transgenic fly strains suggest that more efficient cardiomyocyte contraction, may improve substrate utilization and oxygen consumption within fly hearts, and subsequently organ perfusion and systemic metabolism, and better health- and lifespan. In light of this paradigm and the challenges that mechanogenetics present, we have developed new biological and analytical tools for this grant that will improve the feasibility of assessing the age-related mechanical differences of Drosophila myocardium between wild-type and transgenic lines. Thus, this on-going work will continue to improve our understanding of the inside-outside aging paradigm.