The small G protein RhoA plays a major role in several vascular processes and cardiovascular disorders. Here we analyze the mechanisms of RhoA regulation by serotonin (5-HT) in arterial smooth muscle. 5-HT (0.1-10 mu M) induced activation of RhoA followed by RhoA depletion at 24-72 h. Inhibition of 5-HT1 receptors reduced the early phase of RhoA activation but had no effect on 5-HT-induced delayed RhoA activation and depletion, which were suppressed by the 5-HT transporter inhibitor fluoxetine and the transglutaminase inhibitor monodansylcadaverin and in type 2 transglutaminase-deficient smooth muscle cells. Coimmunoprecipitations demonstrated that 5-HT associated with RhoA both in vitro and in vivo. This association was calcium-dependent and inhibited by fluoxetine and monodansylcadaverin. 5-HT promotes the association of RhoA with the E3 ubiquitin ligase Smurf1, and 5-HT-induced Rho Adepletion was inhibited by the proteasome inhibitor MG132 and the RhoA inhibitor Tat-C3. Simvastatin, the Rho kinase inhibitor Y-27632, small interfering RNA-mediated RhoA gene silencing, and long-term 5-HT stimulation induced Akt activation. In contrast, inhibition of 5-HT-mediated RhoA degradation by MG132 prevented 5-HT-induced Akt activation. Long-term 5-HT stimulation also led to the inhibition of the RhoA/Rho kinase component of arterial contraction. Our data provide evidence that 5-HT, internalized through the 5-HT transporter, is transamidated to RhoA by transglutaminase. Transamidation of RhoA leads to RhoA activation and enhanced proteasomal degradation, which in turn is responsible for Akt activation and contraction inhibition. The observation of transamidation of 5-HT to RhoA in pulmonary artery of hypoxic rats suggests that this process could participate in pulmonary artery remodeling and hypertension.

Guilluy C., R.M. (2007). Transglutaminase-dependent RhoA activation and depletion by serotonin in vascular smooth muscle cells. THE JOURNAL OF BIOLOGICAL CHEMISTRY, 282(5), 2918-2928 [10.1074/jbc.M604195200].

Transglutaminase-dependent RhoA activation and depletion by serotonin in vascular smooth muscle cells

MELINO, GENNARO;
2007

Abstract

The small G protein RhoA plays a major role in several vascular processes and cardiovascular disorders. Here we analyze the mechanisms of RhoA regulation by serotonin (5-HT) in arterial smooth muscle. 5-HT (0.1-10 mu M) induced activation of RhoA followed by RhoA depletion at 24-72 h. Inhibition of 5-HT1 receptors reduced the early phase of RhoA activation but had no effect on 5-HT-induced delayed RhoA activation and depletion, which were suppressed by the 5-HT transporter inhibitor fluoxetine and the transglutaminase inhibitor monodansylcadaverin and in type 2 transglutaminase-deficient smooth muscle cells. Coimmunoprecipitations demonstrated that 5-HT associated with RhoA both in vitro and in vivo. This association was calcium-dependent and inhibited by fluoxetine and monodansylcadaverin. 5-HT promotes the association of RhoA with the E3 ubiquitin ligase Smurf1, and 5-HT-induced Rho Adepletion was inhibited by the proteasome inhibitor MG132 and the RhoA inhibitor Tat-C3. Simvastatin, the Rho kinase inhibitor Y-27632, small interfering RNA-mediated RhoA gene silencing, and long-term 5-HT stimulation induced Akt activation. In contrast, inhibition of 5-HT-mediated RhoA degradation by MG132 prevented 5-HT-induced Akt activation. Long-term 5-HT stimulation also led to the inhibition of the RhoA/Rho kinase component of arterial contraction. Our data provide evidence that 5-HT, internalized through the 5-HT transporter, is transamidated to RhoA by transglutaminase. Transamidation of RhoA leads to RhoA activation and enhanced proteasomal degradation, which in turn is responsible for Akt activation and contraction inhibition. The observation of transamidation of 5-HT to RhoA in pulmonary artery of hypoxic rats suggests that this process could participate in pulmonary artery remodeling and hypertension.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/11
eng
Con Impact Factor ISI
primer DNA; protein glutamine gamma glutamyltransferase; RhoA guanine nucleotide binding protein; serotonin; small interfering RNA; animal; anoxia; aorta; article; C57BL mouse; cell hypoxia; drug effect; enzyme activation; enzymology; genetics; hypertension; kinetics; metabolism; mouse; mouse mutant; muscle contraction; pathophysiology; physiology; pulmonary artery; rat; vascular smooth muscle; Animals; Anoxia; Aorta; Cell Hypoxia; DNA Primers; Enzyme Activation; Hypertension; Kinetics; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle Contraction; Muscle, Smooth, Vascular; Pulmonary Artery; Rats; rhoA GTP-Binding Protein; RNA, Small Interfering; Serotonin; Transglutaminases
Guilluy C., R.M. (2007). Transglutaminase-dependent RhoA activation and depletion by serotonin in vascular smooth muscle cells. THE JOURNAL OF BIOLOGICAL CHEMISTRY, 282(5), 2918-2928 [10.1074/jbc.M604195200].
Guilluy C., Rolli-Derkinderen M., Tharaux P.-L., Melino G., Pacaud P., Loirand G.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/30423
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