Iptakalim inhibited endothelin-1-induced proliferation of human pulmonary arterial smooth muscle cells through the activation of K(ATP) channel.
To determine whether iptakalim inhibited endothelin-1(ET-1)-induced proliferation of human pulmonary arterial smooth muscle cells (PASMCs) through the activation of ATP-sensitive potassium (K(ATP)) channel, the effect of iptakalim on the ET-1-induced proliferation of human PASMCs was examined by [3H]thymidine incorporation, staining with propidium iodide and flow cytometry analyses, measurement of cytosolic free Ca2+ concentration ([Ca2+]cyt) and Western blot for the phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in vitro. The results showed that iptakalim inhibited the ET-1-induced proliferation of human PASMCs, including [3H]thymidine incorporation and the transition of cell cycle phase, and blocked the ET-1-induced transient raise of [Ca2+]cyt, and the ET-1-induced phosphorylation of ERK1/2 in the human PASMCs. Iptakalim exerted a similar role as pinacidil did in human PASMCs and both inhibited the [3H] thymidine incorporation and the transition of cell cycle phase induced by ET-1 in the human PASMCs. Furthermore, we found that the inhibition of iptakalim and pinacidil on the ET-1-induced proliferation of human PASMCs was blocked by glyburide, a selective K(ATP) channel antagonist. These findings provide a strong evidence to support that iptakalim acts as a specific K(ATP) channel opener to antagonize the proliferating effect of ET-1 in the human PASMCs. This study provides further evidence that iptakalim may serve as another candidate drug to treat pulmonary hypertension.
Zhu
Yuming
Y
Department of Respiratory Medicine, the First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China.
Zhang
Shijiang
S
Xie
Weiping
W
Li
Qingling
Q
Zhou
Yanjuan
Y
Wang
Hong
H
D000959:Antihypertensive Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000378:metabolism*; D005434:Flow Cytometry; D005905:Glyburide / Q000494:pharmacology; D006801:Humans; D054086:KATP Channels / Q000819:agonists* / Q000378:metabolism; D049990:Membrane Transport Modulators / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D020110:Pinacidil / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000187:drug effects* / Q000378:metabolism
D000959:Antihypertensive Agents; D019332:Endothelin-1; D054086:KATP Channels; D049990:Membrane Transport Modulators; C502260:N-(1-methylethyl)-1,1,2-trimethylpropylamine; D026902:Potassium Channel Blockers; D011437:Propylamines; D020110:Pinacidil; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D005905:Glyburide; D002118:Calcium