mdl-100907 and dironyl

Cardiac allograft vasculopathy (CAV) is the main obstacle for long-term survival after heart transplantation. Alloimmune mediated chronic vascular rejection results in several mechanisms like platelet activation, immigration of inflammatory cells through the endothelial layer and proliferation and migration of smooth muscle cells (SMCs). Serotonin (5-HT) promotes these processes via activation of 5-HT. CBA/JRj mice recieved aortic grafts from C57BL/6 mice. After transplantation until recovery of organs, recipients were treated with serotonin receptor antagonists: sarpogrelate (5-HT. Elevated serum serotonin levels were significantly reduced after 5-HT. Inhibition of the 5HT/5-HT

Topics: Animals; Aorta; Cell Proliferation; Female; Graft Rejection; Heart Transplantation; Humans; Indoles; Lisuride; Male; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Models, Animal; Serotonin; Serotonin 5-HT2 Receptor Antagonists; Serotonin Antagonists; Succinates; Transendothelial and Transepithelial Migration; Transplantation, Homologous; Urea

Release of 5-hydroxytryptamine (5-HT; serotonin) from activated platelets following microvascular injury leads to tissue fibrosis. 5-HT strongly induces extracellular matrix synthesis in dermal fibroblasts in a transforming growth factor beta 1 (TGF-β1)-dependent manner.. To evaluate anti-fibrotic properties of inhibitors of 5-HT. Stimulation of HADF cells with 5-HT/TGF-β1 led to the increased expression of pro-fibrotic genes which was significantly reduced by both terguride and SB204741. Expression of anti-fibrotic genes was not affected upon incubation with the inhibitors. In 5-HT-stimulated HADF, treatment with terguride and SB204741 decreased type I collagen and α-SMA. In 5-HT/TGF-β1 stimulated HADF, terguride and SB204741 treatment reduced ERK1/2 and STAT3 phosphorylation but did not influence Smad3 phosphorylation.. Terguride and SB204741 reduce pro-fibrotic potential of HADF cells and suppress TGF-β1-mediated non-canonical pathways, ERK1/2 and STAT3 which have been implicated in the regulation of pro-fibrotic genes and in the development of fibrosis. Taken together, our data suggest that 5-HT inhibitors might reduce fibrosis via suppression of TGF-beta1-mediated non-canonical signaling pathways. These observations have important therapeutic implications for fibrotic disorders like scleroderma.

Topics: Adult; Cells, Cultured; Extracellular Matrix Proteins; Extracellular Signal-Regulated MAP Kinases; Female; Fibroblasts; Fibrosis; Gene Expression Regulation; Humans; Indoles; Lisuride; Phenotype; Phosphorylation; Receptor, Serotonin, 5-HT2B; Scleroderma, Systemic; Serotonin; Serotonin 5-HT2 Receptor Antagonists; Signal Transduction; Skin; STAT3 Transcription Factor; Transforming Growth Factor beta1; Urea

Serotonin (5-hydroxytryptamine; 5-HT) is involved in heart valve tissue fibrosis, pulmonary arterial fibrosis, and pulmonary hypertension. We aimed at characterizing the antiserotonergic properties of the ergot alkaloid derivative terguride [1,1-diethyl-3-(6-methyl-8α-ergolinyl)urea] by using functional receptor assays and valvular interstitial cell culture. Terguride showed no vasoconstrictor effect in porcine coronary arteries (5-HT(2A) receptor bioassay) and no relaxant effect in porcine pulmonary arteries (5-HT(2B) receptor bioassay). Terguride behaved as a potent antagonist at 5-HT(2A) receptors (noncompetitive antagonist parameter pD'₂ 9.43) and 5-HT(2B) receptors (apparent pA₂ 8.87). Metabolites of terguride (N″-monodeethylterguride and 6-norterguride) lacked agonism at both sites. N″-monodeethylterguride and 6-norterguride were surmountable antagonists at 5-HT(2A) receptors (pA₂ 7.82 and 7.85, respectively) and 5-HT(2B) receptors (pA₂ 7.30 and 7.11, respectively). Kinetic studies on the effects of terguride in pulmonary arteries showed that the rate to reach drug-receptor equilibrium for terguride was fast. Washout experiments showed that terguride easily disappeared from the receptor biophase. Pretreatment with terguride inhibited 5-HT-induced amplification of ADP-stimulated human platelet aggregation (IC₅₀ 16 nM). In porcine valvular interstitial cells, 5-HT-induced activation of extracellular signal-regulated kinase (ERK) 1/2, an initiator of cellular proliferation and activity, was blocked by terguride as shown by Western blotting. In these cells, the stimulatory effect of 5-HT on [³H]proline incorporation (index of extracellular matrix collagen) was blocked by terguride. Because of the inhibition of both 5-HT(2A) and 5-HT(2B) receptors, platelet aggregation, and cellular proliferation and activity (ERK1/2 phosphorylation and collagen production) terguride may have therapeutic potential in the treatment of fibrotic disorders.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adenosine Diphosphate; Animals; Aortic Valve; Blood Vessels; Cells, Cultured; Collagen; Coronary Vessels; Dose-Response Relationship, Drug; Heart Valves; Humans; In Vitro Techniques; Inhibitory Concentration 50; Ketanserin; Kinetics; Lisuride; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitral Valve; Phosphorylation; Platelet Aggregation; Pulmonary Artery; Serotonin; Serotonin 5-HT2 Receptor Antagonists; Sus scrofa; Vasoconstriction; Vasodilation

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterised by vasoconstriction and remodelling of the pulmonary vasculature. The serotonin (5-hydroxytryptamine (5-HT)) pathway has been shown to play a major role in the pathogenesis of PAH, but pharmacological modulation of this pathway for treatment of PAH is, to date, at a pre-clinical level. Terguride is a 5-HT receptor (5-HTR) antagonist that is well tolerated and clinically approved for ovulation disorders. Immunohistochemistry against 5-HTR(₂A/B) on human lungs revealed their localisation to the vascular smooth muscle layer and quantitative RT-PCR showed 5-HTR(₂B) upregulation in pulmonary artery smooth muscle cells (PASMC) isolated from PAH patients. Proliferation and migration of cultured primary human PASMC were dose-dependently blocked by terguride. Therapeutic 5-HT signalling inhibition was 1) demonstrated in isolated, ventilated and perfused rat lungs and 2) by chronic terguride treatment of rats with monocrotaline (MCT)-induced pulmonary hypertension in a preventive or curative approach. Terguride inhibited proliferation of PASMCs and abolished 5-HT-induced pulmonary vasoconstriction. Chronic terguride treatment prevented dose-dependently the development and progression of MCT-induced PAH in rats. Thus, terguride represents a valuable novel therapeutic approach in PAH.

Topics: Adult; Animals; Cell Proliferation; Cells, Cultured; Dopamine Agonists; Female; Humans; Hypertension, Pulmonary; Lisuride; Lung; Lung Transplantation; Male; Monocrotaline; Muscle, Smooth, Vascular; Pulmonary Artery; Rats; Serotonin 5-HT2 Receptor Antagonists

Idiopathic pulmonary fibrosis (IPF) has a poor prognosis and limited responsiveness to available treatments. It is characterised by epithelial cell injury, fibroblast activation and proliferation and extracellular matrix deposition. Serotonin (5-hydroxytryptamine; 5-HT) induces fibroblast proliferation via the 5-HTR(2A) and 5-HTR(2B) receptors, but its pathophysiological role in IPF remains unclear. A study was undertaken to determine the expression of 5-HT receptors in IPF and experimental lung fibrosis and to investigate the effects of therapeutic inhibition of 5-HTR(2A/B) signalling on lung fibrosis in vivo and in vitro.. Quantitative RT-PCR showed that the expression of 5-HTR(1A/B) and 5-HTR(2B) was significantly increased in the lungs of patients with IPF (n=12) and in those with non-specific interstitial pneumonia (NSIP, n=6) compared with transplant donors (n=12). The expression of 5-HTR(2A) was increased specifically in IPF lungs but not in NSIP lungs. While 5-HTR(2A) protein largely localised to fibroblasts, 5-HTR(2B) localised to the epithelium. To assess the effects of 5HTR(2A/B) inhibition on fibrogenesis in vivo, mice were subjected to bleomycin-induced lung fibrosis and treated with the 5-HTR(2A/B) antagonist terguride (or vehicle) in a therapeutic approach (days 14-28 after bleomycin). Terguride-treated mice had significantly improved lung function and histology and decreased collagen content compared with vehicle-treated mice. Functional in vitro studies showed that terguride is a potent inhibitor of transforming growth factor β(1)- or WNT3a-induced collagen production.. The studies revealed an increased expression of 5-HTR(2A) specifically in IPF. Blockade of 5-HTR(2A/B) signalling by terguride reversed lung fibrosis and is thus a promising therapeutic approach for IPF.

Topics: Animals; Bleomycin; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Humans; Lisuride; Lung; Male; Mice; Mice, Inbred C57BL; Pulmonary Fibrosis; Receptor, Serotonin, 5-HT2A; Receptor, Serotonin, 5-HT2B; Serotonin 5-HT2 Receptor Antagonists; Serotonin Plasma Membrane Transport Proteins