Adenovirus-encoded hammerhead ribozyme to Bcl-2 inhibits neointimal hyperplasia and induces vascular smooth muscle cell apoptosis.
OBJECTIVE
The balance between apoptosis and cell proliferation is vital for cellular homeostasis, yet little is known about the mechanisms that coordinate these two cell fates, particularly in the vessel wall. It is well established that the members of Bcl-2-gene family are regulators of apoptosis, but their role in cellular proliferation is less clear.


METHODS
We analyzed the effects of disrupting Bcl-2 expression in vascular smooth muscle cells (VSMCs) by adenoviral-mediated delivery of a hammerhead ribozyme against bcl-2 mRNA (Ad-Rbz-Bcl-2).


RESULTS
Forced ablation of Bcl-2 in balloon-injured rat carotid arteries reduced cell number and inhibited neointimal hyperplasia. In vitro, VSMCs transduced with the Ad-Rbz-Bcl-2 underwent apoptosis as indicated by a reduction in cell number and DNA fragmentation. Ad-Rbz-Bcl-2-transduced cells also exhibited aberrations in both G1- and S-phases of the cell cycle. However, forced perturbations in cell cycle activity by serum-stimulation or treatment with chemical inhibitors did not affect Ad-Rbz-Bcl-2-induced cell death, indicating that these cell cycle changes are not essential for apoptosis.


CONCLUSIONS
These data show that physiological levels of Bcl-2 are essential for VSMC viability and that ablation of Bcl-2 alters cell cycle activity through the execution of the apoptotic process.
Perlman
H
H
Division of Cardiovascular Research, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135, USA.
Sata
M
M
Krasinski
K
K
Dorai
T
T
Buttyan
R
R
Walsh
K
K
D000256:Adenoviridae / Q000235:genetics; D000704:Analysis of Variance; D000818:Animals; D001013:Aorta, Thoracic; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D020212:Carotid Artery Injuries; D002404:Catheterization / Q000009:adverse effects; D002453:Cell Cycle / Q000235:genetics; D002478:Cells, Cultured; D005434:Flow Cytometry; D019254:Genes, bcl-2; D005822:Genetic Vectors / Q000008:administration & dosage; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D016337:RNA, Catalytic; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016337:RNA, Catalytic