TY - JOUR
T1 - Mechanical stretching of alveolar epithelial cells increases Na+-K+- ATPase activity
AU - Waters, Christopher M.
AU - Ridge, Karen M.
AU - Sunio, G.
AU - Venetsanou, K.
AU - Sznajder, Jacob Iasha
PY - 1999
Y1 - 1999
N2 - Alveolar epithelial cells effect edema clearance by transporting Na+ and liquid out of the air spaces. Active Na+ transport by the basolaterally located Na+-K+-ATPase is an important contributor to lung edema clearance. Because alveoli undergo cyclic stretch in vivo, we investigated the role of cyclic stretch in the regulation of Na+-K+-ATPase activity in alveolar epithelial cells. Using the Flexercell Strain Unit, we exposed a cell line of murine lung epithelial cells (MLE-12) to cyclic stretch (30 cycles/min). After 15 min of stretch (10% mean strain), there was no change in Na+-K+- ATPase activity, as assessed by 86Rb+ uptake. By 30 min and after 60 min, Na+-K+-ATPase activity was significantly increased. When cells were treated with amiloride to block amiloride-sensitive Na+ entry into cells or when cells were treated with gadolinium to block stretch-activated, nonselective cation channels, there was no stimulation of Na+-K+-ATPase activity by cyclic stretch. Conversely, cells exposed to Nystatin, which increases Na+ entry into cells, demonstrated increased Na+K+ATPase activity. The changes in Na+-K+-ATPase activity were paralleled by increased Na+-K+-ATPase protein in the basolateral membrane of MLE-12 cells. Thus, in MLE-12 cells, short-term cyclic stretch stimulates Na+-K+-ATPase activity, most likely by increasing intracellular Na+ and by recruitment of Na+-K+-ATPase subunits from intracellular pools to the basolateral membrane.
AB - Alveolar epithelial cells effect edema clearance by transporting Na+ and liquid out of the air spaces. Active Na+ transport by the basolaterally located Na+-K+-ATPase is an important contributor to lung edema clearance. Because alveoli undergo cyclic stretch in vivo, we investigated the role of cyclic stretch in the regulation of Na+-K+-ATPase activity in alveolar epithelial cells. Using the Flexercell Strain Unit, we exposed a cell line of murine lung epithelial cells (MLE-12) to cyclic stretch (30 cycles/min). After 15 min of stretch (10% mean strain), there was no change in Na+-K+- ATPase activity, as assessed by 86Rb+ uptake. By 30 min and after 60 min, Na+-K+-ATPase activity was significantly increased. When cells were treated with amiloride to block amiloride-sensitive Na+ entry into cells or when cells were treated with gadolinium to block stretch-activated, nonselective cation channels, there was no stimulation of Na+-K+-ATPase activity by cyclic stretch. Conversely, cells exposed to Nystatin, which increases Na+ entry into cells, demonstrated increased Na+K+ATPase activity. The changes in Na+-K+-ATPase activity were paralleled by increased Na+-K+-ATPase protein in the basolateral membrane of MLE-12 cells. Thus, in MLE-12 cells, short-term cyclic stretch stimulates Na+-K+-ATPase activity, most likely by increasing intracellular Na+ and by recruitment of Na+-K+-ATPase subunits from intracellular pools to the basolateral membrane.
KW - Amiloride
KW - Gadolinium
KW - Mechanical ventilation
KW - Nystatin
KW - Pulmonary edema
KW - Sodium transport
KW - Sodium-potassium-adenosine 5'-triphosphatase
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U2 - 10.1152/jappl.1999.87.2.715
DO - 10.1152/jappl.1999.87.2.715
M3 - Article
C2 - 10444632
AN - SCOPUS:0032817317
SN - 8750-7587
VL - 87
SP - 715
EP - 721
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 2
ER -