title: Strain transfer in ventricular cardiomyocytes to their transverse tubular system revealed by scanning confocal microscopy.
abstract: The transverse tubular system (t-system) is a major site for signaling in mammalian ventricular cardiomyocytes including electrical signaling and excitation-contraction coupling. It consists of membrane invaginations, which are decorated with various proteins including mechanosensitive ion channels. Here, we investigated mechanical modulation of the t-system. By applying fluorescent markers, three-dimensional scanning confocal microscopy, and methods of digital image analysis, we studied isolated ventricular cardiomyocytes under different strains. We demonstrate that strain at the cellular level is transmitted to the t-system, reducing the length and volume of tubules and altering their cross-sectional shape. Our data suggest that a cellular strain of as little as 5% affects the shape of transverse tubules, which has important implications for the function of mechanosensitive ion channels found in them. Furthermore, our study supports a prior hypothesis that strain can cause fluid exchange between the t-system and extracellular space.
authors.affiliation: Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: McNary
authors.forename: John H B
authors.initials: JH
authors.lastname: Bridge
authors.forename: Frank B
authors.initials: FB
authors.lastname: Sachse
mesh_terms: D000818:Animals; D022081:Cell Surface Extensions / Q000378:metabolism*; D006352:Heart Ventricles / Q000166:cytology*; D007091:Image Processing, Computer-Assisted; D018613:Microscopy, Confocal; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D011817:Rabbits; D013314:Stress, Mechanical