cAMP inhibits proliferation in most cell types triggering different and sometimes opposing molecular pathways. p85alpha (the PI3K regulatory subunit) is phosphorylated by cAMP/PKA in certain cell lineages but its effects on vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are unknown. In the present study we evaluated: i) the role of p85alpha in the integration of cAMP/PKA-dependent signaling on the regulation of VSMC and EC growth in vitro and ii) the effects of PKA-modified-p85alpha on neointimal hyperplasia and endothelial healing after balloon injury in vivo. Plasmid constructs carrying wild type and PKA-modified p85alpha were employed in VSMCs and ECs in vitro and after balloon injury in rat carotid arteries in vivo. cAMP/PKA reduced VSMC proliferation through p85alpha phosphorylation. Transfected PKA-activated-p85alpha binds p21(ras) reducing ERK 1/2 activation and VSMC proliferation in vitro. In contrast, EC proliferation inhibition by cAMP is independent from PKA modification of p85alpha and ERK 1/2 inhibition; indeed, PKA-activated-p85alpha did not inhibit per se ERK 1/2 activation and proliferation in ECs in vitro. Interestingly, cAMP reduced both VSMC and EC apoptotic death through p85alpha phosphorylation. Accordingly, PKA-activated-p85alpha triggered Akt activation reducing both VSMC and EC apoptosis in vitro. Finally, compared to controls, vascular gene transfer of PKA-activated-p85alpha significantly reduced neointimal formation after balloon injury in rats, without inhibiting endothelial regeneration of the injured arterial segment. In conclusions, PKA-activated-p85alpha integrates cAMP/PKA signaling differently in VSMCs and ECs. By reducing neointimal hyperplasia without inhibiting endothelial regeneration, it exerts a protective effect against restenosis after balloon injury. Key words: Restenosis, smooth muscle cells, endothelial cells, cAMP.
Differential Regulation of Vascular Smooth Muscle and Endothelial Cell Proliferation In Vitro and In Vivo by cAMP/PKA-activated p85{alpha}PI3K / Torella, D.; Gasparri, C.; Ellison, G. M.; Curcio, A.; Leone, A.; Vicinanza, C.; Galuppo, V.; Mendicino, I.; Sacco, W.; Aquila, I.; Surace, F. C.; Luposella, M.; Stillo, G.; Agosti, V.; Cosentino, C.; Avvedimento, VITTORIO ENRICO; Indolfi, C.. - In: AMERICAN JOURNAL OF PHYSIOLOGY. HEART AND CIRCULATORY PHYSIOLOGY. - ISSN 0363-6135. - ELETTRONICO. - 297:(2009), pp. 2015-2025. [10.1152/ajpheart.00738.2009]
Differential Regulation of Vascular Smooth Muscle and Endothelial Cell Proliferation In Vitro and In Vivo by cAMP/PKA-activated p85{alpha}PI3K.
AVVEDIMENTO, VITTORIO ENRICO;
2009
Abstract
cAMP inhibits proliferation in most cell types triggering different and sometimes opposing molecular pathways. p85alpha (the PI3K regulatory subunit) is phosphorylated by cAMP/PKA in certain cell lineages but its effects on vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are unknown. In the present study we evaluated: i) the role of p85alpha in the integration of cAMP/PKA-dependent signaling on the regulation of VSMC and EC growth in vitro and ii) the effects of PKA-modified-p85alpha on neointimal hyperplasia and endothelial healing after balloon injury in vivo. Plasmid constructs carrying wild type and PKA-modified p85alpha were employed in VSMCs and ECs in vitro and after balloon injury in rat carotid arteries in vivo. cAMP/PKA reduced VSMC proliferation through p85alpha phosphorylation. Transfected PKA-activated-p85alpha binds p21(ras) reducing ERK 1/2 activation and VSMC proliferation in vitro. In contrast, EC proliferation inhibition by cAMP is independent from PKA modification of p85alpha and ERK 1/2 inhibition; indeed, PKA-activated-p85alpha did not inhibit per se ERK 1/2 activation and proliferation in ECs in vitro. Interestingly, cAMP reduced both VSMC and EC apoptotic death through p85alpha phosphorylation. Accordingly, PKA-activated-p85alpha triggered Akt activation reducing both VSMC and EC apoptosis in vitro. Finally, compared to controls, vascular gene transfer of PKA-activated-p85alpha significantly reduced neointimal formation after balloon injury in rats, without inhibiting endothelial regeneration of the injured arterial segment. In conclusions, PKA-activated-p85alpha integrates cAMP/PKA signaling differently in VSMCs and ECs. By reducing neointimal hyperplasia without inhibiting endothelial regeneration, it exerts a protective effect against restenosis after balloon injury. Key words: Restenosis, smooth muscle cells, endothelial cells, cAMP.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
