NCX-IP3R Crosstalk Maintains Calcium Oscillations to Regulate Angiogenic Signaling in Endothelial Cells

Blood endothelial cells regulate angiogenesis through low-frequency calcium oscillations that coordinate migration and proliferation, yet the mechanisms governing these signaling dynamics remain poorly understood and difficult to manipulate for tissue regeneration. Here, we combine computational analysis, microfluidic electrical stimulation, and mathematical modeling to demonstrate that sodium-calcium crosstalk between the sodium-calcium exchanger (NCX) and inositol trisphosphate receptor (IP3R) is a key regulator of endothelial calcium oscillations and downstream angiogenic responses. We show that characteristic endothelial calcium oscillations emerge when maximal NCX-mediated calcium efflux and IP3R-mediated calcium influx are aligned at similar intracellular calcium concentrations, producing prolonged low-calcium quasi-steady states punctuated by rapid calcium spikes. This oscillatory behavior can be modulated through pharmacological inhibition, changes in extracellular sodium, or growth factor signaling. We further identify distinct transient and sustained calcium signaling patterns associated with angiogenesis that can be recapitulated by electrical stimulation, activating angiogenic gene expression and vascular network formation without exogenous growth factor supplementation. Together, these findings establish NCX-IP3R crosstalk as a fundamental mechanism governing endothelial calcium signaling and introduce precise control of ionic dynamics as a strategy for engineering angiogenic responses that can be used for various applications in regenerative medicine.