An Electrical Impedance-Based Method for Quantitative Real-Time Analysis of Semaphorin-Elicited Endothelial Cell Collapse.

Semaphorins (SEMA) are chemorepulsive guidance cues that, acting through plexin receptors, inhibit integrin-mediated cell adhesion to the extracellular matrix. The ensuing cell retraction and collapse is a key biological event downstream of SEMA/plexin signaling that is however hard to precisely quantify. Here, we describe a quantitative approach that allows monitoring over time the evolution of SEMA3E/plexin D1-elicited endothelial cell collapse. This method exploits the xCELLigence platform, an electrical impedance-based system in which microelectronic sensor arrays are integrated into the bottom of microplate wells. Measuring electrical impedance allows real-time monitoring of changes in endothelial cell morphology and adhesion induced by SEMA3E via plexin D1. Afterwards, analogic electrical impedance measurements are converted into digital numeric signals that can then be analyzed by mathematical and statistical methods.