Published online before print June 15, 2006, doi: 10.1161/01.RES.0000232323.86227.8b
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2006 American Heart Association, Inc.
Molecular Medicine |
Selective Activation of Nuclear Phospholipase D-1 by G Protein–Coupled Receptor Agonists in Vascular Smooth Muscle Cells
From the Département Lipoprotéines and Médiateurs Lipidiques (S.G, M.L., J.-P.S., B.P., M.R., M.B.-D.), CPTP, INSERM Unité 563, CHU Purpan, BP 3028, 31024 Toulouse Cedex 3, France; the laboratoire de Signalisation et Croissance Cellulaire (P.D.), Institut de Recherche en Immunovirologie et Cancérologie, Université de Montréal, Canada; and Département Biochimie (K.L.), Université Sciences II, Genève, Switzerland.
Correspondence to Monique Breton-Douillon, Département Lipoprotéines and Médiateurs lipidiques, CPTP, INSERM Unité 563, Bâtiment C, CHU Purpan, BP 3028, 31024 Toulouse Cedex 3, France. E-mail monique.douillon{at}toulouse.inserm.fr
Recent studies highlight the existence of an autonomous nuclear lipid metabolism related to cellular proliferation. However, the importance of nuclear phosphatidylcholine (PC) metabolism is poorly understood. Therefore, we were interested in nuclear PCs as a source of second messengers and, particularly, nuclear phospholipase D (PLD) identification in membrane-free nuclei isolated from pig aorta vascular smooth muscle cells (VSMCs). Using immunoblot experiment, in vitro PLD assay with fluorescent substrate and confocal microscopy analysis, we demonstrated that only PLD1 is expressed in VSMC nucleus, whereas PLD1 and PLD2 are present in VSMC. Inhibition of RhoA and protein kinase C
(PKC) by C3-exoenzyme and PKC pseudosubstrate inhibitor, respectively, conducted a decrease of phosphatidylethanol production. On the other hand, treatment of intact VSMCs, but not nuclei, with phosphoinositide 3-kinase (PI3K) inhibitors prevented partially nuclear PLD1 activity, indicating for the first time that PI3K may have a role in nuclear PLD regulation. In addition, lysophosphatidic acid (LPA) or angiotensin II treatment of VSMCs resulted in an increase of intranuclear PLD activity, whereas platelet-derived growth factor and epidermal growth factor have no significant effect. Moreover, pertussis toxin induced a decrease of LPA-stimulated nuclear PLD1 activity, suggesting that heterotrimeric Gi/G0 protein involvement in intranuclear PLD1 regulation. We also show that LPA-induced nuclear PLD1 activation implied PI3K/PKC pathway activation and PKC nuclear translocation as well as nuclear RhoA activation. Thus, the characterization of an endogenous PLD1 that could regulate PC metabolism inside VSMC nucleus provides a new role for this enzyme in control of vascular fibroproliferative disorders.
Key Words: PLD1 • nucleus • smooth muscle cells
This article has been cited by other articles:
 |
|
 |
|
  L. Moreno, G. Frazziano, A. Cogolludo, L. Cobeno, J. Tamargo, and F. Perez-Vizcaino Role of Protein Kinase C{zeta} and Its Adaptor Protein p62 in Voltage-Gated Potassium Channel Modulation in Pulmonary Arteries Mol. Pharmacol., November 1, 2007; 72(5): 1301 - 1309. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. Goetzl Diverse pathways for nuclear signaling by G protein-coupled receptors and their ligands FASEB J, March 1, 2007; 21(3): 638 - 642. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ushio-Fukai Nuclear Phospholipase D1 in Vascular Smooth Muscle: Specific Activation by G Protein-Coupled Receptors Circ. Res., July 21, 2006; 99(2): 116 - 118. [Full Text] [PDF]
|
|