Potier-Cartereau Marie, Gautier Mathieu, Ravalet Noemie, Ducrocq Elfi, Hamard Sophie, LeGuennec Jean-Yves, Vandier Christophe, Herault Olivier
N2C UMR 1069, University of Tours, INSERM, Tours, France.
LPCM UR 4667, University of Picardie Jules Verne, Amiens, France.
Bioelectricity. 2022 May 26;4(2):103-107. doi: 10.1089/bioe.2022.0015. eCollection 2022 May.
The aim of this study was to characterize the functional expression of sodium-calcium exchangers on AFT024 cell line, a murine model of mesenchymal stem/stromal cells (MSCs) supporting human primitive hematopoiesis. All current-clamp and voltage-clamp experiments were performed using the perforated patch whole-cell recording technique with amphotericin B. The membrane potential of -14 mV shifted to -35 mV when lowering the external sodium concentration to 0.33 mM and an increase of cytosolic calcium concentration was observed. KB-R7943, a selective blocker of cardiac sodium-calcium exchangers, also named , induced a hyperpolarization at physiological sodium concentration while it blocked the hyperpolarization observed at low sodium concentration. This demonstrates for the first time the presence of the sodium-calcium exchangers in AFT024 cells and provides initial evidence that the membrane potential of these stromal cells is maintained depolarized by this exchanger. Lowering external sodium concentration and KB-R7943 had no effect on the membrane potential of 2018 cells, a nonhematopoietic-supportive cell line. Since is differentially expressed in AFT024 cells as compared with nonhematopoietic supportive cells with more restricted differentiation potential, this study suggests a potential role of this sodium-calcium exchanger, in the differentiation process or hematopoietic support of MSCs.
本研究的目的是表征钠钙交换体在AFT024细胞系中的功能表达，AFT024细胞系是一种支持人类原始造血的间充质干/基质细胞（MSC）的小鼠模型。所有的电流钳和电压钳实验均使用两性霉素B穿孔膜片全细胞记录技术进行。当将细胞外钠浓度降低至0.33 mM时，膜电位从-14 mV转变为-35 mV，并且观察到胞质钙浓度增加。KB-R7943是一种心脏钠钙交换体的选择性阻滞剂，也称为，在生理钠浓度下诱导超极化，而在低钠浓度下它则阻断观察到的超极化。这首次证明了AFT024细胞中存在钠钙交换体，并提供了初步证据表明这些基质细胞的膜电位通过这种交换体维持去极化。降低细胞外钠浓度和使用KB-R7943对2018细胞（一种非造血支持细胞系）的膜电位没有影响。由于与分化潜能更受限的非造血支持细胞相比，在AFT024细胞中差异表达，本研究表明这种钠钙交换体在MSC的分化过程或造血支持中可能发挥作用。
