PGE2 amplifies the effects of IL-1beta on vascular smooth muscle cell de-differentiation: a consequence of the versatility of PGE2 receptors 3 due to the emerging expression of adenylyl cyclase 8

• Published in: Journal of cellular physiology 2006-09, Vol.208 (3), p.495
• Main Authors: Clément, Nathalie, Glorian, Martine, Raymondjean, Michel, Andréani, Marise, Limon, Isabelle
• Format: Article
• Language: English
• Subjects: Adenylyl Cyclases - genetics; Adenylyl Cyclases - metabolism; Animals; Aorta, Thoracic; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cells, Cultured; Cyclic AMP - metabolism; Dinoprostone - pharmacology; Drug Synergism; Gene Expression Regulation, Enzymologic - drug effects; Interleukin-1 - pharmacology; Male; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - physiology; Phospholipases A - genetics; Phospholipases A - metabolism; Phospholipases A2; Rats; Receptors, Prostaglandin E - classification; Receptors, Prostaglandin E - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering - genetics; Transcription, Genetic - drug effects; Vasoconstriction - drug effects
• ISSN: 0021-9541

Transition of vascular smooth muscle cells from a contractile/quiescent to a secretory/proliferative phenotype is one of the critical steps in atherosclerosis and is instigated by pro-inflammatory cytokines released from macrophages that have infiltrated into the vascular wall. In most inflammatory diseases, cell activation induced by these compounds leads to a massive production of type E2 prostaglandin (PGE2) which often takes over and even potentiates the pro-inflammatory cytokine-related effects. To evaluate PGE2 incidence on atheroma plaque development, we investigated whether and how this compound could enhance the dedifferentiation of smooth muscle cells initially induced by interleukin-1beta (IL-1beta). To address this issue, we took advantage of vascular smooth muscle cells in primary culture and tracked two markers: PLA2 secretion and alpha-actin filament disorganization. In such a context, we found that PGE2 synergizes with IL-1beta to further enhance the phenotype transition of smooth muscle cells, through cAMP-protein kinase A. As indicated by pharmacological studies, the full PGE2-dependent potentiation of IL-1beta induced PLA2 secretion is associated with a change of regulation exerted by the subtypes 3 G(i)-coupled PGE2 receptors toward adenylyl cyclase(s) activated by the subtype 4 G(s)-linked PGE2 receptor. Whereas on contractile cells, stimulated subtypes 3 inhibit type 4-dependent PLA2 secretion, this negative regulation is switched to positive on IL-1beta-treated cells. Using real time PCR, pharmacological tools and small interfering RNA (siRNA), we demonstrated that the different integration of PGE2 signals depends on the upregulation of calcium/calmodulin stimulable adenylyl cyclase 8.