Seminar Series

Discontinuous Dielectrophoresis Enabled Investigation of Shear Stress Stimulus on Intracellular Calcium Signalling of Non-Adherent Cells

Speaker

Dr Rebecca Soffe

Institute

University of Canterbury

Time & Place

Fri, 03 Mar 2017 14:00:00 NZDT in Kirkwood KH03

Abstract

Presently, microfluidic and conventional biological strategies are limited in the shear stress range, a form of mechanical stress, which can be investigated in regards to non-adherent cells; such that strategies are limited to approximately 20 dyn/cm2. In consequence, these strategies would not enable Arterial and Venus systems to be extensively investigated, for instance, as such systems experience a shear stress range from 10 to 60 dyn/cm2. Discontinuous Dielectrophoresis, a novel microfluidic based approach was designed to overcome the limited shear stress range, such that a shear stress range up to 63 dyn/cm2 can be investigated. Furthermore, Discontinuous Dielectrophoresis enables various shear stimulus scenarios to be investigated, for example, concurrent shear stress and chemical stimulation.

I focus on three shear stimulus scenarios and the subsequent influence on intracellular calcium signalling, with the use of HEK-293-TRPV4 as the model cell line. Firstly, I investigated the influence of planar shear stress, in which high levels of a singular shear stress level were applied to the non-adherent cells, with shear stresses up to 63 dyn/cm2 investigated. Experiments indicated, reduced cellular and peak response times, increased pharmacological efficacy, and percentage of activated cells, with increasing shear stress. Secondly, I investigated concurrent shear stress and chemical (TRPV4-selective agonist, GSK1016790A) stimulation. The experiments revealed that shear stress sensitises GSK1016790A-evoked intracellular calcium signalling of cells in a shear-stimulus dependent manner. Thirdly, I explored temporal (pulsatile) and spatial shear stress stimulation. With the spatial shear stress gradient following similar trends to that was observed for the case of planar shear stress. Consequently, these different scenarios suggested that the role of TRPV4 may be underestimated in endothelial cells - which experience high levels of shear stress; thus in turn, highlighting the importance of conducting studies at high levels of shear stress.