Single-site sonoporation disrupts actin cytoskeleton organization

J R Soc Interface. 2014 Mar 26;11(95):20140071. doi: 10.1098/rsif.2014.0071. Print 2014 Jun 6.

Abstract

Sonoporation is based upon an ultrasound-microbubble cavitation routine that physically punctures the plasma membrane on a transient basis. During such a process, the actin cytoskeleton may be disrupted in tandem because this network of subcellular filaments is physically interconnected with the plasma membrane. Here, by performing confocal fluorescence imaging of single-site sonoporation episodes induced by ultrasound-triggered collapse of a single targeted microbubble, we directly observed immediate rupturing of filamentary actin (F-actin) at the sonoporation site (cell type: ZR-75-30; ultrasound frequency: 1 MHz; peak negative pressure: 0.45 MPa; pulse duration: 30 cycles; bubble diameter: 2-4 µm). Also, through conducting a structure tensor analysis, we observed further disassembly of the F-actin network over the next 60 min after the onset of sonoporation. The extent of F-actin disruption was found to be more substantial in cells with higher uptake of sonoporation tracer. Commensurate with this process, cytoplasmic accumulation of globular actin (G-actin) was evident in sonoporated cells, and in turn the G-actin : F-actin ratio was increased in a trend similar to drug-induced (cytochalasin D) actin depolymerization. These results demonstrate that sonoporation is not solely a membrane-level phenomenon: organization of the actin cytoskeleton is concomitantly perturbed.

Keywords: F-actin disassembly; G-actin accumulation; actin cytoskeleton; characteristic time; single-site sonoporation; structure tensor analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actins / metabolism*
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Humans
  • Microscopy, Confocal
  • Sound*

Substances

  • Actins