TY - JOUR
T1 - Mechanisms of NFATc3 activation by increased superoxide and reduced hydrogen peroxide in pulmonary arterial smooth muscle
AU - Ramiro-Diaz, Juan Manuel
AU - Giermakowska, Wieslawa
AU - Weaver, John M.
AU - Jernigan, Nikki L.
AU - Gonzalez Bosc, Laura V.
N1 - Publisher Copyright:
© 2014 the American Physiological Society.
PY - 2014/11/15
Y1 - 2014/11/15
N2 - We recently demonstrated increased superoxide (O2•−) and decreased H2O2levels in pulmonary arteries of chronic hypoxia-exposed wild-type and normoxic superoxide dismutase 1 (SOD1) knockout mice. We also showed that this reciprocal change in O2•− and H2O2 is associated with elevated activity of nuclear factor of activated T cells isoform c3 (NFATc3) in pulmonary arterial smooth muscle cells (PASMC). This suggests that an imbalance in reactive oxygen species levels is required for NFATc3 activation. However, how such imbalance activates NFATc3 is unknown. This study evaluated the importance of O2•− and H2O2 in the regulation of NFATc3 activity. We tested the hypothesis that an increase in O2•− enhances actin cytoskeleton dynamics and a decrease in H2O2 enhances intracellular Ca2+ concentration, contributing to NFATc3 nuclear import and activation in PASMC. We demonstrate that, in PASMC, endothelin-1 increases O2•− while decreasing H2O2 production through the decrease in SOD1 activity without affecting SOD protein levels. We further demonstrate that O2•− promotes, while H2O2 inhibits, NFATc3 activation in PASMC. Additionally, increased O2•−-to-H2O2 ratio activates NFATc3, even in the absence of a Gq protein-coupled receptor agonist. Furthermore, O2•−-dependent actin polymerization and low intracellular H2O2 concentration-dependent increases in intracellular Ca2+ concentration contribute to NFATc3 activation. Together, these studies define important and novel regulatory mechanisms of NFATc3 activation in PASMC by reactive oxygen species.
AB - We recently demonstrated increased superoxide (O2•−) and decreased H2O2levels in pulmonary arteries of chronic hypoxia-exposed wild-type and normoxic superoxide dismutase 1 (SOD1) knockout mice. We also showed that this reciprocal change in O2•− and H2O2 is associated with elevated activity of nuclear factor of activated T cells isoform c3 (NFATc3) in pulmonary arterial smooth muscle cells (PASMC). This suggests that an imbalance in reactive oxygen species levels is required for NFATc3 activation. However, how such imbalance activates NFATc3 is unknown. This study evaluated the importance of O2•− and H2O2 in the regulation of NFATc3 activity. We tested the hypothesis that an increase in O2•− enhances actin cytoskeleton dynamics and a decrease in H2O2 enhances intracellular Ca2+ concentration, contributing to NFATc3 nuclear import and activation in PASMC. We demonstrate that, in PASMC, endothelin-1 increases O2•− while decreasing H2O2 production through the decrease in SOD1 activity without affecting SOD protein levels. We further demonstrate that O2•− promotes, while H2O2 inhibits, NFATc3 activation in PASMC. Additionally, increased O2•−-to-H2O2 ratio activates NFATc3, even in the absence of a Gq protein-coupled receptor agonist. Furthermore, O2•−-dependent actin polymerization and low intracellular H2O2 concentration-dependent increases in intracellular Ca2+ concentration contribute to NFATc3 activation. Together, these studies define important and novel regulatory mechanisms of NFATc3 activation in PASMC by reactive oxygen species.
KW - Actin cytoskeleton
KW - Calcium
KW - Endothelin-1
KW - Hydrogen peroxide
KW - NFATc3
KW - Superoxide
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U2 - 10.1152/ajpcell.00244.2014
DO - 10.1152/ajpcell.00244.2014
M3 - Article
C2 - 25163518
AN - SCOPUS:84925114737
SN - 0363-6135
VL - 307
SP - C928-C938
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 10
ER -