Dual effect of serotonin on growth of bovine pulmonary artery smooth muscle cells in culture.

Abstract

We have previously reported that serotonin (5-hydroxytryptamine [SHT]) alters cultured bovine pulmonary artery smooth muscle cell (SMC) configuration through two different regulatory mechanisms. We now report that 5HT also regulates SMC growth through these same two mechanisms-a stimulatory event initiated intracellularly and inhibition of growth resulting from a cell surface action. 5HT (1 ,M) plus 0.1 mM iproniazid (a 5HT metabolic inhibitor) produced a severalfold stimulation of DNA synthesis (as measured by ['H]thymidine incorporation) of SMCs after a 17-24-hour incubation with only a slight elevation of cellular cAMP. This stimulatory effect responded synergistically with other growth factors including plateletderived growth factor, fibroblast growth factor, and epidermal growth factor and was effectively reversed by 5HT uptake inhibition. It was not produced by 5-hydroxyindoleacetic acid, a metabolite of 5HT. In the presence of 1 pM 5HT plus 0.1 mM isobutylmethylxanthine (IBMX), cAMP was elevated eightfold, dendritic formation occurred, and ['H]thymidine labeling of SMCs was inhibited. Inhibition of labeling by ['H]thymidine was mimicked by other agents that elevated cellular cAMP (10 ,uM histamine, 1 ,M isoproterenol plus 0.1 mM IBMX, and 10 ,uM forskolin) and by 1 mM dibutyryl cAMP. This inhibitory effect was not blocked by either inhibition of 5HT uptake or 5HT-receptor antagonists ketanserin (5HT2); methiothepin, spiperone, and mianserin (5HT1/5HT2); and 3-tropanyl-indole-3-carboxylate and 3-tropanyl-3,5-dichlorobenzoate (5HT3). However, similar to 5HT, the 5HT,A agonist, (+)-8-hydroxy-(+)- We have previously found that 5HT causes a configurational change (dendritic formation) of bovine pulmonary artery SMCs in culture through actions at two different locations of the cell, one that requires 5HT uptake into the cell'5 and another that by guest on May 9, 2018

The Lbc Rho Guanine Nucleotide Exchange Factor/α-Catulin Axis Functions in Serotonin-induced Vascular Smooth Muscle Cell Mitogenesis and RhoA/ROCK Activation*

“…3 and maintained in RPMI 1640 medium with 10% fetal bovine serum (FBS), 100 units/ml of penicillin, and 100 g/ml of streptomycin, and used between passages 3 and 8. Human embryonic kidney (HEK) 293T cells (ATCC) were grown in Dulbecco's modified essential medium (DMEM) (Invitrogen) with 10% FBS and 100 units/ml of penicillin and 100 g/ml of streptomycin.…”

“…At near-physiologic concentrations, 5-HT is mitogenic for certain smooth muscle cell types including cultured pulmonary arterial smooth muscle cells (PASMC) (3). Extensive clinical and experimental studies link 5-HT to idiopathic pulmonary arterial hypertension (PAH) (4), a progressive disease that is ultimately fatal despite available therapies.…”

Activation of GATA-4 by Serotonin in Pulmonary Artery Smooth Muscle Cells

“…Cell Culture and Reagents-Bovine PASMC were isolated and cultured in RPMI 1640 medium containing 10% fetal bovine serum, 1% penicillin/streptomycin, and 0.5% amphotericin B as previously described (1). Cells (passages 0 -6) were growth-arrested for 72 h in medium containing 0.1% fetal bovine serum and treated with 5-HT (Sigma-Aldrich).…”

“…Proliferation of smooth muscle cells is an important component of pulmonary vascular remodeling that results in increased medial muscular wall thickness. Among a number of mediators of pulmonary hypertension, serotonin (5-hydroxytryptamine (5-HT) 1 ) appears to play an important role in the remodeling of the pulmonary circulation (1)(2)(3).…”

“…1 The abbreviations used are: 5-HT, 5-hydroxytryptamine; MEK, mitogen-activated protein kinase/extracellular signal-regulated kinase kinase; ERK, extracellular signal-regulated kinase; SERT, serotonin transporter; PASMC, pulmonary artery smooth muscle cells; ROS, reactive oxygen species; ET-1, endothelin-1; PDGF, platelet-derived growth factor; EMSA, Electrophoretic mobility shift assay.…”