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H2S-donating sildenafil (ACS6) inhibits superoxide formation and gp91phox expression in arterial endothelial cells: role of protein kinases A and G

  1. S Muzaffar1,*,
  2. J Y Jeremy1,*,
  3. A Sparatore2,
  4. P Del Soldato3,
  5. G D Angelini1,
  6. N Shukla1

Article first published online: 29 JAN 2009

DOI: 10.1038/bjp.2008.326

Issue

British Journal of Pharmacology

British Journal of Pharmacology

Volume 155, Issue 7, pages 984–994, December 2008

Additional Information

How to Cite

Muzaffar, S., Jeremy, J. Y., Sparatore, A., Del Soldato, P., Angelini, G. D. and Shukla, N. (2008), H2S-donating sildenafil (ACS6) inhibits superoxide formation and gp91phox expression in arterial endothelial cells: role of protein kinases A and G. British Journal of Pharmacology, 155: 984–994. doi: 10.1038/bjp.2008.326

Author Information

  1. 1

    Department of Cardiac Surgery, Bristol Royal Infirmary, Bristol Heart Institute, University of Bristol, Bristol, UK

  2. 2

    Istituto di Chimica Farmaceutica e Tossicologica, University of Milan, Milan, Italy

  3. 3

    CTG Pharma SRL, Milan, Italy

*Department of Cardiac Surgery, Bristol Royal Infirmary, Bristol Heart Institute, Cardiac AR Sciences, Marlborough Street, Bristol BS2 8HW, UK. E-mail: s.muzaffar@bristol.ac.uk
Department of Cardiac Surgery, Bristol Royal Infirmary, Bristol Heart Institute, Cardiac AR Sciences, Marlborough Street, Bristol BS2 8HW, UK. E-mail: j.y.jeremy@bris.ac.uk

Publication History

  1. Issue published online: 29 JAN 2009
  2. Article first published online: 29 JAN 2009
  3. (Received February 27, 2008, Revised July 7, 2008, Accepted July 10, 2008)

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Keywords:

  • superoxide;
  • NADPH oxidase;
  • hydrogen sulphide;
  • endothelial cells;
  • cAMP

Background and purpose:

Superoxide (O2•−), derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, is associated with acute respiratory distress syndrome (ARDS). NADPH oxidase activity and expression are blocked by nitric oxide (NO) and sildenafil. As another gas, hydrogen sulphide (H2S) is formed by blood vessels, the effect of sodium hydrosulphide (NaHS) and the H2S-donating derivative of sildenafil, ACS6, on O2•− formation and the expression of gp91phox (a catalytic subunit of NADPH oxidase) in porcine pulmonary arterial endothelial cells (PAECs) was investigated.

Experimental approach:

PAECs were incubated with 10 ng mL−1 tumour necrosis factor-α (TNFα) (±NaHS or ACS6), both of which released H2S, for 2 h or 16 h. O2•− was measured. Expression of gp91phox was measured by western blotting and the role of cyclic AMP (cAMP) and/or cyclic GMP was assessed using protein kinase inhibitors.

Key results:

After either 2- or 16-h incubations, O2•− formation by PAECs was inhibited by NaHS or ACS6, with IC50 values of about 10 nM and less than 1 nM, respectively. Both 100 nM NaHS and 1 nM ACS6 completely inhibited gp91phox expression induced by TNFα. The effects of NaHS were blocked by the inhibition of protein kinase A (PKA), but not PKG, and not by the inhibition of guanylyl cyclase. Effects of ACS6 were blocked by inhibition of both PKA and PKG. Both NaHS and ACS6 augmented cAMP formation.

Conclusion and implications:

H2S inhibited O2•− formation and upregulation of NADPH oxidase in PAECs through the adenylyl cyclase-PKA pathway. ACS6 may be effective in treating ARDS through both elevation of cAMP and inhibition of phosphodiesterase type 5 activity.

British Journal of Pharmacology (2008) 155, 984–994; doi:10.1038/bjp.2008.326; published online 1 September 2008

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