Both authors contributed equally to this work.
Phosphodiesterase-4 inhibition improves corticosteroid insensitivity in pulmonary endothelial cells under oxidative stress
Article first published online: 5 NOV 2012
© 2012 John Wiley & Sons A/S
Volume 68, Issue 1, pages 64–73, January 2013
How to Cite
Phosphodiesterase-4 inhibition improves corticosteroid insensitivity in pulmonary endothelial cells under oxidative stress. Allergy 2012; DOI: 10.1111/all.12055., , , , , .
Edited by: Marek Sanak
- Issue published online: 4 DEC 2012
- Article first published online: 5 NOV 2012
- Manuscript Accepted: 19 SEP 2012
- Regional Government. Grant Number: Prometeo/2008/045
- Generalitat Valenciana. Grant Number: AP-178/11
- Spanish Government. Grant Numbers: CB06/06/0027, Prometeo/2008/045, AP-178/11
- CIBERES. Grant Numbers: CB06/06/0027, Prometeo/2008/045, AP-178/11
- cigarette smoke;
- glucocorticoid insensitivity;
- phosphodiesterase-4 inhibitor;
- pulmonary artery endothelial cells
Several clinical studies have shown that smoking in asthmatics and chronic obstructive pulmonary disease patients is closely associated with corticosteroid refractoriness. In this work, we have analyzed glucocorticoid insensitivity in human pulmonary artery endothelial cells (HPAECs) under cigarette smoke extract (CSE) exposure as well as the possible additive effects of the combination therapy with a phosphodiesterase (PDE)-4 inhibitor.
Interleukin (IL)-8 was measured in cell supernatants by ELISA. Histone deacetylase (HDAC), histone acetylase (HAT), and intracellular cAMP levels were measured by colorimetric assays and enzyme immunoassay, respectively. PDE4 isotypes and glucocorticoid receptor (GR)-α and β expression were measured by real-time RT-PCR.
The PDE4 inhibitor rolipram dose dependently inhibited the IL-8 secretion induced by CSE 5%. In contrast, dexamethasone 1 μM did not show inhibitory effect on IL-8 secretion. Combination of subeffective rolipram concentrations at 10 nM increased the inhibitory effect of dexamethasone to ~45% of inhibition. Cigarette smoke extract 5% inhibited HDAC activity and increased HAT activity generating glucocorticoid insensitivity. Rolipram did not modify the HDAC activity, however partially inhibited the increase in HAT activity at 1 μM. PDE4 isotypes were up-regulated by CSE 5% with the consequent cAMP down-regulation. Dexamethasone reduced all PDE4 isotypes expression and showed additive effects with rolipram enhancing cAMP levels. Furthermore, rolipram enhanced GR-α expression and inhibited the increase in GR-β induced by CSE.
Combination of rolipram and dexamethasone shows additive properties in HPAECs under glucocorticoid insensitive conditions. These results may be of potential value in future anti-inflammatory therapies using combination of PDE4 inhibitors and glucocorticoids.