Cell Biochemistry and Biophysics

, Volume 45, Issue 2, pp 167–176

Location-dependent photogeneration of calcium waves in HeLa cells

  • Shigeki Iwanaga
  • Tomoyuki Kaneko
  • Katsumasa Fujita
  • Nicholas Smith
  • Osamu Nakamura
  • Tetsuro Takamatsu
  • Satoshi Kawata
Original Article

DOI: 10.1385/CBB:45:2:167

Cite this article as:
Iwanaga, S., Kaneko, T., Fujita, K. et al. Cell Biochem Biophys (2006) 45: 167. doi:10.1385/CBB:45:2:167

Abstract

The calcium ion (Ca2+) concentrations in a cell are responsible for the control of vital cellular functions and have been widely studied as a means to investigate and control cell activities. Here, we demonstrate Ca2+ wave generation in HeLa cells by femtosecond laser irradiation and show unexpected properties of the Ca2+ release and propagation. When the laser was focused in the cell cytoplasm, Ca2+ release was independent of both external Ca2+ influx and the phosphoinositide-phospholipase C (PLC) signaling pathway. The nucleus was not a susceptible target for laser-induced Ca2+ release, whereas irradiation of the plasma membrane produced evidence of transient poration, through which the extracellular solution could enter the cell. By chelating extracellular Ca2+, we found that laser-induced influx of ethylene glycol tetra-acetic acid (EGTA) can compete with calcium-induced calcium release and significantly delay or suppress the onset of the Ca2+ wave in the target cell. Intercellular Ca2+ propagation was adenosine triphosphate-dependent and could be observed even when the target cell cytosolic Ca2+ rise was suppressed by influx of EGTA. The irradiation effect on overall cell viability was also tested and found to be low (85% at 6h after irradiation by 60 mW average power). Laser-induced Ca2+ waves can be reliably generated by controlling the exposure and focal position and do not require the presence of caged Ca2+. The technique has the potential to replace other methods of Ca2+ stimulation, which either require additional caged molecules in the cell or do not have an interaction that is as well localized.

Index Entries

Intracellular calciumcell signalinglaser surgerynear-infrared laserviability

Copyright information

© Humana Press Inc. 2006

Authors and Affiliations

  • Shigeki Iwanaga
    • 1
  • Tomoyuki Kaneko
    • 1
  • Katsumasa Fujita
    • 1
  • Nicholas Smith
    • 2
  • Osamu Nakamura
    • 1
    • 2
  • Tetsuro Takamatsu
    • 3
  • Satoshi Kawata
    • 1
    • 4
  1. 1.Department of Applied Physics, Graduate School of EngineeringOsaka UniversitySuita, OsakaJapan
  2. 2.Department of Frontier Biosciences, Graduate School of Frontier BiosciencesOsaka UniversitySuita, OsakaJapan
  3. 3.Department of Pathology and Cell RegulationKyoto Prefectural University of MedicineKyotoJapan
  4. 4.RIKENWako, SaitamaJapan