Supplementary material - Impact of Na+ permeation on collective migration of pulmonary arterial endothelial cells (Xu et al)

Endothelial migration is necessary for wound healing and angiogenesis. Na+ has been incriminated as an important cellular signal mediating migration, although the ion channels regulating Na+ permeation that contribute to migration remain poorly understood. First, we studied the contribution of extracellular Na+ to scratch wound healing. Second, we studied the effects of Na+ channel inhibitors inhibiting ENaC, NCX, Orai1, and/or TRPC4 to scratch wound healing. Third, we studied the contribution of Orai1 expression to scratch and non-scratch wound healing in the presence and absence of extracellular Na+. All studies were conducted using pulmonary artery endothelial cells (PAEC). We found that permeation of extracellular Na+ is necessary for efficient and cohesive migration of PAEC monolayers. The processes of wound healing displayed two phases: a fast healing phase within 5 hours followed by a slow-healing phase between 5 and 24 hours. Among the examined Na+ channels, Na+ permeation through ENaC produced prompt and largest effect on wound healing, Na+ permeation through NCX produced small and delayed effect, Na+ permeation through Orai1 produced small and short-term effect, and Na+ permeation through TRPC1/4 produced insignificant effect. Both extracellular Na+ and Orai1 contribute to scratch wound healing, whereas only extracellular Na+ but not Orai1 contributes to cell migration in the absence of injury.