TY - JOUR
T1 - Endothelin-1 contributes to increased NFATc3 activation by chronic hypoxia in pulmonary arteries
AU - de Frutos, Sergio
AU - Diaz, Juan Manuel Ramiro
AU - Nitta, Carlos H.
AU - Sherpa, Mingma L.
AU - Gonzalez Bosc, Laura V.
PY - 2011/8
Y1 - 2011/8
N2 - Chronic hypoxia (CH) activates the Ca2 2+-dependent transcriptionfactor nuclear factor of activated T cells isoform c3 (NFATc3) in mouse pulmonary arteries. However, the mechanism of this response has not been explored. Since we have demonstrated that NFATc3 is required for CH-induced pulmonary arterial remodeling, establishing how CH activates NFATc3 is physiologically significant. The goal of this study was to test the hypothesis that endothelin-1 (ET-1) contributes to CH-induced NFATc3 activation. We propose that this mechanism requires increased pulmonary arterial smooth muscle cell (PASMC) intracellular Ca2 2+ concentration ([Ca2 2+]i) and stimulation of RhoA/Rho kinase (ROK), leading to calcineurin activation and actin cytoskeleton polymerization, respectively. We found that: 1) CH increases pulmonary arterial pre-pro-ET-1 mRNA expression and lung RhoA activity; 2) inhibition of ET receptors, calcineurin, L-type Ca 2+ channels, and ROK blunts CH-induced NFATc3 activation in isolated intrapulmonary arteries from NFAT-luciferase reporter mice; and 3) both ET-1-induced NFATc3 activation in isolated mouse pulmonary arteries ex vivo and ET-1-induced NFATc3-green fluorescence protein nuclear import in human PASMC depend on ROK and actin polymerization. This study suggests that CH increases ET-1 expression, thereby elevating PASMC [Ca2 2+]i and RhoA/ROK activity. As previously demonstrated, elevated [Ca2 2+]i is required to activate calcineurin, which dephosphorylates NFATc3, allowing its nuclear import. Here, we demonstrate that ROK increases actin polymerization, thus providing structural support for NFATc3 nuclear transport.
AB - Chronic hypoxia (CH) activates the Ca2 2+-dependent transcriptionfactor nuclear factor of activated T cells isoform c3 (NFATc3) in mouse pulmonary arteries. However, the mechanism of this response has not been explored. Since we have demonstrated that NFATc3 is required for CH-induced pulmonary arterial remodeling, establishing how CH activates NFATc3 is physiologically significant. The goal of this study was to test the hypothesis that endothelin-1 (ET-1) contributes to CH-induced NFATc3 activation. We propose that this mechanism requires increased pulmonary arterial smooth muscle cell (PASMC) intracellular Ca2 2+ concentration ([Ca2 2+]i) and stimulation of RhoA/Rho kinase (ROK), leading to calcineurin activation and actin cytoskeleton polymerization, respectively. We found that: 1) CH increases pulmonary arterial pre-pro-ET-1 mRNA expression and lung RhoA activity; 2) inhibition of ET receptors, calcineurin, L-type Ca 2+ channels, and ROK blunts CH-induced NFATc3 activation in isolated intrapulmonary arteries from NFAT-luciferase reporter mice; and 3) both ET-1-induced NFATc3 activation in isolated mouse pulmonary arteries ex vivo and ET-1-induced NFATc3-green fluorescence protein nuclear import in human PASMC depend on ROK and actin polymerization. This study suggests that CH increases ET-1 expression, thereby elevating PASMC [Ca2 2+]i and RhoA/ROK activity. As previously demonstrated, elevated [Ca2 2+]i is required to activate calcineurin, which dephosphorylates NFATc3, allowing its nuclear import. Here, we demonstrate that ROK increases actin polymerization, thus providing structural support for NFATc3 nuclear transport.
KW - Cytoskeletal dynamics
KW - Nuclear factor of activated T cells isoform c3
KW - Pulmonary
KW - Rho kinase
KW - Smooth muscle
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U2 - 10.1152/ajpcell.00029.2011
DO - 10.1152/ajpcell.00029.2011
M3 - Article
C2 - 21525433
AN - SCOPUS:79960972329
SN - 0363-6143
VL - 301
SP - C441-C450
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 2
ER -