title: In situ mechanical analysis of myofibrillar perturbation and aging on soft, bilayered Drosophila myocardium.
abstract: Drosophila melanogaster is a genetically malleable organism with a short life span, making it a tractable system in which to study mechanical effects of genetic perturbation and aging on tissues, e.g., impaired heart function. However, Drosophila heart-tube studies can be hampered by its bilayered structure: a ventral muscle layer covers the contractile cardiomyocytes. Here we propose an atomic force microscopy-based analysis that uses a linearized-Hertz method to measure individual mechanical components of soft composite materials. The technique was verified using bilayered polydimethylsiloxane. We further demonstrated its biological utility via its ability to resolve stiffness changes due to RNA interference to reduce myofibrillar content or due to aging in Drosophila myocardial layers. This protocol provides a platform to assess the mechanics of soft biological composite systems and, to our knowledge, for the first time, permits direct measurement of how genetic perturbations, aging, and disease can impact cardiac function in situ.
authors.affiliation: Department of Bioengineering, University of California at San Diego, La Jolla, California, USA.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Kaushik
authors.forename: Alexander
authors.initials: A
authors.lastname: Fuhrmann
authors.forename: Anthony
authors.initials: A
authors.lastname: Cammarato
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Engler
mesh_terms: D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D004129:Dimethylpolysiloxanes / Q000494:pharmacology; D004331:Drosophila melanogaster / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology*; D055785:Gene Knockdown Techniques; D006321:Heart / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D018625:Microscopy, Atomic Force; D009206:Myocardium / Q000648:ultrastructure; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009210:Myofibrils / Q000187:drug effects / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D036103:Nanotechnology; D009928:Organ Specificity / Q000187:drug effects
chemical_list: D004129:Dimethylpolysiloxanes; D018995:Myosin Heavy Chains