Acta Pharmacologica Sinica (2009) 30: 175-183; doi: 10.1038/aps.2008.30; published online 26th January 2009

¹Department of Respiratory Medicine, The First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China; ²Department of Pathogen Biology, Nanjing Medical University, Nanjing 210029, China; ³Department of Cardiothoracic Surgery, The First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China; ⁴The Clinical Experiment Center, The First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China

Aim: To investigate the anti-proliferative effect of iptakalim (Ipt), a newly selective K_ATP channel opener, in endothelin-1 (ET-1)-induced human pulmonary arterial smooth muscle cells (PASMCs) using proteomic analysis.

Methods: Human PASMCs were incubated with ET-1 (10^-8 mol/L) and ET-1 (10^-8 mol/L) plus iptaklim (10^-5 mol/L) for 24 h. Analysis via 2-DE gel electrophoresis and MALDI-TOF-MS was employed to display the different protein profiles of whole-cell protein from cultures of control, ET-1 treatment alone, and treatment with ET-1 and iptaklim combined. Real time RT-PCR and Western blot analysis were used to confirm the proteomic analysis.

Results: When iptakalim inhibited the proliferative effect of ET-1 in human PASMCs by opening the K_ATP channels, the expression of different groups of cellular proteins was changed, including cytoskeleton-associated proteins, plasma membrane proteins and receptors, chaperone proteins, ion transport–associated proteins, and glycolytic and metabolism-associated proteins. We found that iptakalim could inhibit the proliferation of human PASMCs partly by affecting the expression of Hsp60, vimentin, nucleoporin P54 (NUP54) and Bcl-X_L by opening the K_ATP channel.

Conclusion: The data suggest that a wide range of signaling pathways may be involved in abolishing ET-1-induced proliferation of human PASMCs following iptakalim treatment.

Keywords: pulmonary arterial smooth muscle cells; K_ATP channel opener; iptakalim; proteomics; proliferation