Proteomic analysis of the effect of iptakalim on human pulmonary arterial smooth muscle cell proliferation.

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.