Affordable Access

Publisher Website

Estimation of the mechanical connection between apical stress fibers and the nucleus in vascular smooth muscle cells cultured on a substrate

Authors
Journal
Journal of Biomechanics
0021-9290
Publisher
Elsevier
Publication Date
Volume
47
Issue
6
Identifiers
DOI: 10.1016/j.jbiomech.2014.01.042
Keywords
  • Cell Biomechanics
  • Prestress
  • Force Transmission
  • Laser Ablation
  • Cytoskeleton
  • Mechanotransduction
Disciplines
  • Biology

Abstract

Abstract Actin stress fibers (SFs) generate intercellular tension and play important roles in cellular mechanotransduction processes and the regulation of various cellular functions. We recently found, in vascular smooth muscle cells (SMCs) cultured on a substrate, that the apical SFs running across the top surface of the nucleus have a mechanical connection with the cell nucleus and that their internal tension is transmitted directly to the nucleus. However, the effects of the connecting conditions and binding forces between SFs and the nucleus on force transmission processes are unclear at this stage. Here, we estimated the mechanical connection between apical SFs and the nucleus in SMCs, taking into account differences in the contractility of individual SFs, using experimental and numerical approaches. First, we classified apical SFs in SMCs according to their morphological characteristics: one subset appeared pressed onto the apical surface of the nucleus (pressed SFs), and the other appeared to be smoothly attached to the nuclear surface (attached SFs). We then dissected these SFs by laser irradiation to release the pretension, observed the dynamic behavior of the dissected SFs and the nucleus, and estimated the pretension of the SFs and the connection strength between the SFs and the nucleus by using a simple viscoelastic model. We found that pressed SFs generated greater contractile force and were more firmly connected to the nuclear surface than were attached SFs. We also observed line-like concentration of the nuclear membrane protein nesprin 1 and perinuclear DNA that was significantly located along the pressed SFs. These results indicate that the internal tension of pressed SFs is transmitted to the nucleus more efficiently than that of attached SFs, and that pressed SFs have significant roles in the regulation of the nuclear morphology and rearrangement of intranuclear DNA.

There are no comments yet on this publication. Be the first to share your thoughts.