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Chronic hypoxia limits H 2 O 2 -induced inhibition of ASIC1-dependent store-operated calcium entry in pulmonary arterial smooth muscle
Our laboratory shows that acid-sensing ion channel 1 (ASIC1) contributes to the development of hypoxic pulmonary hypertension by augmenting store-operated Ca 2+ entry (SOCE) that is associated with enhanced agonist-induced vasoconstriction and arterial remodeling. However, this enhanced Ca 2+ influx...
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| Published in: | American journal of physiology. Lung cellular and molecular physiology 2014-09, Vol.307 (5), p.L419-L430 |
|---|---|
| Main Authors: | , , , , , , |
| Format: | Article |
| Language: | English |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | Our laboratory shows that acid-sensing ion channel 1 (ASIC1) contributes to the development of hypoxic pulmonary hypertension by augmenting store-operated Ca
2+
entry (SOCE) that is associated with enhanced agonist-induced vasoconstriction and arterial remodeling. However, this enhanced Ca
2+
influx following chronic hypoxia (CH) is not dependent on an increased ASIC1 protein expression in pulmonary arterial smooth muscle cells (PASMC). It is well documented that hypoxic pulmonary hypertension is associated with changes in redox potential and reactive oxygen species homeostasis. ASIC1 is a redox-sensitive channel showing increased activity in response to reducing agents, representing an alternative mechanism of regulation. We hypothesize that the enhanced SOCE following CH results from removal of an inhibitory effect of hydrogen peroxide (H
2
O
2
) on ASIC1. We found that CH increased PASMC superoxide (O
2
·−
) and decreased rat pulmonary arterial H
2
O
2
levels. This decrease in H
2
O
2
is a result of decreased Cu/Zn superoxide dismutase expression and activity, as well as increased glutathione peroxidase (GPx) expression and activity following CH. Whereas H
2
O
2
inhibited ASIC1-dependent SOCE in PASMC from control and CH animals, addition of catalase augmented ASIC1-mediated SOCE in PASMC from control rats but had no further effect in PASMC from CH rats. These data suggest that, under control conditions, H
2
O
2
inhibits ASIC1-dependent SOCE. Furthermore, H
2
O
2
levels are decreased following CH as a result of diminished dismutation of O
2
·−
and increased H
2
O
2
catalysis through GPx-1, leading to augmented ASIC1-dependent SOCE. |
|---|---|
| ISSN: | 1040-0605 1522-1504 |
| DOI: | 10.1152/ajplung.00095.2014 |