5-Hydroxytryptamine-induced proliferation of pulmonary artery smooth muscle cells are extracellular signal-regulated kinase pathway dependent.
OBJECTIVE
To investigate the effect of 5-hydroxytryptamine transporter (5-HTT) inhibitor fluoxetine and antisense oligodeoxynucleotide (ODN) to extracelluar signal-regulated kinases (ERKs) on pulmonary arterial smooth muscle cells (PASMCs) proliferation induced by 5-HT.


METHODS
Liposomal transfection was used to introduce ODNs to ERK1/2 into cultured rat PASMCs and the transfection efficiency was measured by observing the uptake of the fluorecein isothiocynate (FITC)-labeled antisense ODN in PASMCs. The effects of 5-HTT selective inhibitor fluoxetine and ODNs on the proliferation of PASMCs were evaluated by cell number counting and cell cycle analysis, and measured by microculture tetrazolium (MTT) assay and flow cytometry (FCM), respectively.


RESULTS
Liposomes mediated the transfection of ODNs into PASMCs with high efficiency. MTT assay showed fluoxetine (10 micromol/L, 1 micromol/L, and 100 nmol/L) concentration dependently inhibited the proliferation of PASMCs induced by 5-HT (1 micromol/L) in vitro. The proliferation rate of PASMCs by 5-HT was significantly inhibited by pretreatment with ERK1/2 antisense ODN (0.2 micromol/L) from 251%+/-18% to 86%+/-5% (P<0.01). Flow cytometric analysis of cell cycle distribution showed that the increase of 5-HT induced S phase fraction (SPF) and proliferation index (PI) were significantly inhibited by fluoxetine (1 micromol/L) or antisense ODN with SPF from 36%+/-4% to 26%+/-3% and 24%+/-4%, and PI from 34%+/-2% to 29%+/-2% and 24%+/-2%, respectively.


CONCLUSIONS
5-HTT mediates the mitogenic effect of 5-HT on PASMCs and the proliferation of PASMCs induced by 5-HT is dependent on ERKs signal pathway.
Song
Dan
D
Department of Clinical Pharmacology, China Medical University, Shenyang 110001, China.
Wang
Huai-liang
HL
Wang
Shuang
S
Zhang
Xin-hua
XH
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000502:physiology*; D005473:Fluoxetine / Q000494:pharmacology*; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors; D049990:Membrane Transport Modulators; D026901:Membrane Transport Proteins / Q000037:antagonists & inhibitors; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D016196:S Phase / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D014162:Transfection
D048049:Extracellular Signal-Regulated MAP Kinases; D005473:Fluoxetine; D008562:Membrane Glycoproteins; D049990:Membrane Transport Modulators; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D012701:Serotonin; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors; C493232:Slc6a4 protein, rat