Published online before print April 16, 2009, doi: 10.1161/CIRCRESAHA.109.194357
© 2009 American Heart Association, Inc.
Cellular Biology |
3-Deazaadenosine Prevents Smooth Muscle Cell Proliferation and Neointima Formation by Interfering With Ras Signaling
From the Departments of Cardiology (D.G.S., M.T., F.R., G.W., H.T.), Biochemistry (D.G.S., K.T.P.), Pathology (L.F., R.M.B.), and Radiology (W.R., A.C.L.), Justus-Liebig University, Giessen, Germany; Department of Internal Medicine/Cardiology (W.H.), Central Hospital, Suhl, Germany; and Department of Physiology and Biomedical Engineering (A.C.L.), Mayo Clinic College of Medicine, Rochester, Minn.
Correspondence to Daniel Sedding, MD, Department of Internal Medicine I/Cardiology, Giessen University, Klinikstrasse 36, 35392 Giessen, Germany. E-mail daniel.sedding{at}innere.med.uni-giessen.de
3-Deazaadenosine (c3Ado) is a potent inhibitor of S-adenosylhomocysteine hydrolase, which regulates cellular methyltransferase activity. In the present study, we sought to determine the effect of c3Ado on vascular smooth muscle cell (VSMC) function and neointima formation in vivo. c3Ado dose-dependently prevented the proliferation and migration of human coronary VSMCs in vitro. This was accompanied by an increased expression of the cyclin-dependent kinase inhibitors p21WAF1/Cip1, p27Kip1, a decreased expression of G1/S phase cyclins, and a lack of retinoblastoma protein hyperphosphorylation. In accordance with these findings, fluorescence-activated cell-sorting analysis of propidium iodide–stained cells indicated a cell cycle arrest in the G0/G1 phase. Importantly, c3Ado did not affect the number of viable (trypan blue exclusion) or apoptotic cells (TUNEL). Mechanistically, c3Ado prevented FCS-induced Ras carboxyl methylation and membrane translocation and activity by inhibiting isoprenylcysteine carboxyl methyltransferase and reduced FCS-induced extracellular signal-regulated kinase (ERK)1/2 and Akt phosphorylation in a dose-dependent manner. Conversely, rescuing signal transduction by overexpression of a constitutive active Ras mutant abrogated c3Ado’s effect on proliferation. For in vivo studies, the femoral artery of C57BL/6 mice was dilated and mice were fed a diet containing 150 µg of c3Ado per day. c3Ado prevented dilation-induced Ras activation, as well as ERK1/2 and Akt phosphorylation in vivo. At day 21, VSMC proliferation (proliferating-cell nuclear antigen [PCNA]-positive cells), as well as the neointima/media ratio (0.7±0.2 versus 1.6±0.4; P<0.05) were significantly reduced, without any changes in the number of apoptotic cells. Our data indicate that c3Ado interferes with Ras methylation and function and thereby with mitogenic activation of ERK1/2 and Akt, preventing VSMC cell cycle entry and proliferation and neointima formation in vivo. Thus, therapeutic inhibition of S-adenosylhomocysteine hydrolase by c3Ado may represent a save and effective novel approach to prevent vascular proliferative disease.
Key Words: neointima formation • restenosis • signal transduction • smooth muscle cells • vascular smooth muscle cell proliferation
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Circ. Res. 2009 104: 1139-1141.
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