Myeloperoxidase-derived oxidants inhibit sarco/endoplasmic reticulum Ca2+-ATPase activity and perturb Ca2+ homeostasis in human coronary artery endothelial cells
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Myeloperoxidase-derived oxidants inhibit sarco/endoplasmic reticulum Ca2+-ATPase activity and perturb Ca2+ homeostasis in human coronary artery endothelial cells. / Cook, Naomi L; Viola, Helena M; Sharov, Victor S; Hool, Livia C; Schöneich, Christian; Davies, Michael Jonathan.
In: Free Radical Biology & Medicine, Vol. 52, No. 5, 01.03.2012, p. 951-61.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Myeloperoxidase-derived oxidants inhibit sarco/endoplasmic reticulum Ca2+-ATPase activity and perturb Ca2+ homeostasis in human coronary artery endothelial cells
AU - Cook, Naomi L
AU - Viola, Helena M
AU - Sharov, Victor S
AU - Hool, Livia C
AU - Schöneich, Christian
AU - Davies, Michael Jonathan
N1 - Copyright © 2011 Elsevier Inc. All rights reserved.
PY - 2012/3/1
Y1 - 2012/3/1
N2 - The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) plays a critical role in Ca(2+) homeostasis via sequestration of this ion in the sarco/endoplasmic reticulum. The activity of this pump is inhibited by oxidants and impaired in aging tissues and cardiovascular disease. We have shown previously that the myeloperoxidase (MPO)-derived oxidants HOCl and HOSCN target thiols and mediate cellular dysfunction. As SERCA contains Cys residues critical to ATPase activity, we hypothesized that HOCl and HOSCN might inhibit SERCA activity, via thiol oxidation, and increase cytosolic Ca(2+) levels in human coronary artery endothelial cells (HCAEC). Exposure of sarcoplasmic reticulum vesicles to preformed or enzymatically generated HOCl and HOSCN resulted in a concentration-dependent decrease in ATPase activity; this was also inhibited by the SERCA inhibitor thapsigargin. Decomposed HOSCN and incomplete MPO enzyme systems did not decrease activity. Loss of ATPase activity occurred concurrent with oxidation of SERCA Cys residues and protein modification. Exposure of HCAEC, with or without external Ca(2+), to HOSCN or HOCl resulted in a time- and concentration-dependent increase in intracellular Ca(2+) under conditions that did not result in immediate loss of cell viability. Thapsigargin, but not inhibitors of plasma membrane or mitochondrial Ca(2+) pumps/channels, completely attenuated the increase in intracellular Ca(2+) consistent with a critical role for SERCA in maintaining endothelial cell Ca(2+) homeostasis. Angiotensin II pretreatment potentiated the effect of HOSCN at low concentrations. MPO-mediated modulation of intracellular Ca(2+) levels may exacerbate endothelial dysfunction, a key early event in atherosclerosis, and be more marked in smokers because of their higher SCN(-) levels.
AB - The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) plays a critical role in Ca(2+) homeostasis via sequestration of this ion in the sarco/endoplasmic reticulum. The activity of this pump is inhibited by oxidants and impaired in aging tissues and cardiovascular disease. We have shown previously that the myeloperoxidase (MPO)-derived oxidants HOCl and HOSCN target thiols and mediate cellular dysfunction. As SERCA contains Cys residues critical to ATPase activity, we hypothesized that HOCl and HOSCN might inhibit SERCA activity, via thiol oxidation, and increase cytosolic Ca(2+) levels in human coronary artery endothelial cells (HCAEC). Exposure of sarcoplasmic reticulum vesicles to preformed or enzymatically generated HOCl and HOSCN resulted in a concentration-dependent decrease in ATPase activity; this was also inhibited by the SERCA inhibitor thapsigargin. Decomposed HOSCN and incomplete MPO enzyme systems did not decrease activity. Loss of ATPase activity occurred concurrent with oxidation of SERCA Cys residues and protein modification. Exposure of HCAEC, with or without external Ca(2+), to HOSCN or HOCl resulted in a time- and concentration-dependent increase in intracellular Ca(2+) under conditions that did not result in immediate loss of cell viability. Thapsigargin, but not inhibitors of plasma membrane or mitochondrial Ca(2+) pumps/channels, completely attenuated the increase in intracellular Ca(2+) consistent with a critical role for SERCA in maintaining endothelial cell Ca(2+) homeostasis. Angiotensin II pretreatment potentiated the effect of HOSCN at low concentrations. MPO-mediated modulation of intracellular Ca(2+) levels may exacerbate endothelial dysfunction, a key early event in atherosclerosis, and be more marked in smokers because of their higher SCN(-) levels.
KW - Calcium
KW - Calcium Signaling
KW - Cells, Cultured
KW - Chloramines
KW - Coronary Vessels
KW - Endoplasmic Reticulum
KW - Endothelial Cells
KW - Humans
KW - Hypochlorous Acid
KW - Oxidants
KW - Oxidation-Reduction
KW - Peroxidase
KW - Sarcoplasmic Reticulum
KW - Sarcoplasmic Reticulum Calcium-Transporting ATPases
KW - Sulfhydryl Compounds
KW - Thiocyanates
U2 - 10.1016/j.freeradbiomed.2011.12.001
DO - 10.1016/j.freeradbiomed.2011.12.001
M3 - Journal article
C2 - 22214747
VL - 52
SP - 951
EP - 961
JO - Free Radical Biology & Medicine
JF - Free Radical Biology & Medicine
SN - 0891-5849
IS - 5
ER -
ID: 128975200