Surface Plasmon Resonance Monitoring of Cell Monolayer Integrity: Implication of Signaling Pathways Involved in Actin-Driven Morphological Remodeling

Morphological changes occurring in individual cells largely influence the physiological functions of various cell layers. The control of barrier function of epithelia and endothelia is a prime example of processes highly dependent on cellular morphology and cell layer integrity. Here, we applied the surface plasmon resonance (SPR) technique to the quantification of cellular activity of an epithelial cell monolayer stimulated by angiotensin II. The analysis of the SPR signal shows reproducible concentration-dependent biphasic responses after cell activation with angiotensin II. Phase-contrast and confocal microscopy imaging was performed to link the SPR signal to molecular and global morphological remodeling. The SPR signal was observed to be in relation with the rapid cell contraction and the subsequent cell spreading observed by phase-contrast microscopy. Additionally, the temporal redistribution of actin, observed by confocal microscopy after angiotensin II stimulation, was also found to be consistent with the SPR signal variation. The modulation of signaling pathways involved in actin-myosin driven cell contraction confirms the direct implication of actin structures in the SPR response. Additionally, we show that the intracellular calcium mobilization associated with angiotensin II stimulation did not produce any significant SPR signal variation. Altogether, our results demonstrate that SPR is a rapid label-free method to study cellular activity and molecular mechanisms implicated in the modulation of the integrity of a cell monolayer in relation to cytoskeleton remodeling with associated cell morphological changes.