Ca2+ waves across gaps in non-excitable cells induced by femtosecond laser exposure

Abstract

Calcium is a second messenger in all cells for various cellular processes. It was found in astrocytes and neurons that femtosecond laser stimulation could induce Ca2+ wave propagation. In this work, a femtosecond laser with a power above a certain threshold was focused on single HeLa/HEK293T cells for Ca2+ mobilization. Several types of Ca2+ oscillation patterns were found in neighboring cells. The Ca2+ wave propagated very fast across 40-μm gaps in the Ca2+-free medium mediated by the adenosine-triphosphate released from cells. This approach could provide a clean methodology to investigate the Ca2+ dynamics in non-excitable cells.

Reply to 'Mechanism for microtsunami-induced intercellular mechanosignalling'

“…These molecules then diffuse to neighbouring cells and activate purinergic receptors, including those coupled to GPCRs, resulting in a propagating intercellular Ca 2+ wave. They cite previous studies [3][4][5] ) and smaller spatial extent (~200 μm radius) as compared with μT-ICS waves (4.5 μm s −1 and ~400 μm radius, respectively) reported in our paper. Importantly, our studies employed human vascular endothelial cells (HUVECs) whose physiological function requires mechanosensitivity to hemodynamic shear stress.…”

Regulation of Cellular Molecular Signaling by Light (Invited Paper)

“…A lot of cell processes are activated simultaneously and some of them can feedback to contribute to more Ca 2+ release, like ROS generated by two-photon excitation of endogenous absorbers [103] and/or oxidative stress to ER [104]. Interestingly, intercellular Ca 2+ wave propagation among excitable cells or non-excitable cells was also observed after the intracellular Ca 2+ release by femtosecond laser [6,98,105]. He et al proposed three possible mechanisms: 1) Ca 2+ signaling molecules such as ATP was released from the photostimulated cell and diffused away to excite Ca 2+ release in surrounding cells; 2) mechanical stress of shear flow by the plasma generation impacted surrounding cells to activate the release of Ca 2+ ; 3) mechanical stress of acoustic wave stimulated Ca 2+ release along its propagation [106].…”

“…He et al proposed three possible mechanisms: 1) Ca 2+ signaling molecules such as ATP was released from the photostimulated cell and diffused away to excite Ca 2+ release in surrounding cells; 2) mechanical stress of shear flow by the plasma generation impacted surrounding cells to activate the release of Ca 2+ ; 3) mechanical stress of acoustic wave stimulated Ca 2+ release along its propagation [106]. Several works suggested the Ca 2+ wave from a single cell stimulated by femtosecond laser at a relatively safe power was mediated by ATP which diffused in the cell medium and activated Ca 2+ release in surrounding cells through ATP receptors on cell membrane [91,105,107]. A recent work by Compton et al demonstrated the contribution of mechanical stress by a high-power nanosecond laser focused outside cell to Ca 2+ wave generation [108].…”

A comprehensive approach to decipher biological computation to achieve next generation high-performance exascale computing.

“…Previous studies of femtosecond stimulation of neurons [10][11][12][13][14][15][16][17][18][19][20] have proposed essentially two mechanisms induced by the laser: photo-disruption and photo-poration, where the transition from a dominant disruption mechanism to a dominant poration mechanism occurs at laser power densities ~ 5×10 11 W/cm 2 (e.g. ~35mW of 800nm, 100fs, 80MHz light focused with a 0.9 NA objective).…”

“…In neuroscience, NIR femtosecond lasers have been utilized as a noncontact, noninvasive alternative (or complement) to electrical stimulation of neurons and astrocytes [10][11][12]. Combined with fluorescence calcium imaging, this approach to neural stimulation has been applied to the study of neural activity, connectivity, and function [11,13,14].…”