Ubiquitin-proteasome pathway as a new target for the prevention of restenosis.

Abstract

BACKGROUND:

The ubiquitin-proteasome system is the major intracellular protein degradation pathway in eucaryotic cells. It regulates central mediators of proliferation, inflammation, and apoptosis that are fundamental pathomechanisms in the development of vascular restenosis.

METHODS AND RESULTS:

Effects of proteasome inhibition on neointima formation were studied in a balloon injury model in the rat carotid artery. Local application of the proteasome inhibitor MG132 (1 mmol/L) resulted in significant inhibition of intimal hyperplasia, that is, by 74% (P=0.008). This effect was accompanied by decreased proliferation, reduced infiltration of macrophages, and prolonged apoptosis, as determined by immunohistochemical and TUNEL analyses. Functional effects of proteasome inhibition on proliferation, activation of nuclear factor kappa B, and apoptosis were further characterized in rat primary vascular smooth muscle cells. MG132 dose-dependently inhibited vascular smooth muscle cell proliferation with 50% inhibition at 10 micromol/L. TNFalpha-induced degradation of IkappaBalpha and beta was blocked, and activation of nuclear factor kappa B was suppressed in a concentration-dependent manner in bandshift assays. Moreover, proteasome inhibition (1 to 50 micromol/L MG132) induced apoptotic cell death up to 80%, as confirmed by DNA/Histone-ELISA and TUNEL-FACS analysis. Specificity of proteasome inhibition was shown by accumulation of multiubiquitinylated proteins and accumulation of specific proteasomal substrates.

CONCLUSIONS:

These proof-of-principle experiments demonstrate that inhibition of the ubiquitin-proteasome system effectively reduces neointima formation in vivo, which corresponds to strong antiproliferative, anti-inflammatory, and proapoptotic effects in vitro and in vivo. Our data suggest the ubiquitin-proteasome system as a new target in the prevention of vascular restenosis.

• Authors: Silke Meiners, Michael Laule, Wim Rother, Christoph Guenther, Ines Prauka, Peter Muschick, Gert Baumann, Peter-Michael Kloetzel, Karl Stangl
• Journal: Circulation (Circulation) Vol. 105 Issue 4 Pg. 483-9 (Jan 29 2002) ISSN: 1524-4539 [Electronic] United States
• PMID: 11815432 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cysteine Proteinase Inhibitors
• Leupeptins
• Multienzyme Complexes
• NF-kappa B
• Ubiquitin
• Cysteine Endopeptidases
• Proteasome Endopeptidase Complex
• benzyloxycarbonylleucyl-leucyl-leucine aldehyde

Topics

• Angioplasty, Balloon (adverse effects)
• Animals
• Apoptosis
• Carotid Stenosis (etiology, pathology, prevention & control)
• Cell Division (drug effects)
• Cells, Cultured
• Cysteine Endopeptidases
• Cysteine Proteinase Inhibitors (pharmacology)
• Graft Occlusion, Vascular (pathology, prevention & control)
• Inflammation (prevention & control)
• Leupeptins (pharmacology)
• Multienzyme Complexes (antagonists & inhibitors)
• Muscle, Smooth, Vascular (cytology, drug effects, metabolism)
• NF-kappa B (antagonists & inhibitors)
• Proteasome Endopeptidase Complex
• Rats
• Rats, Wistar
• Substrate Specificity
• Ubiquitin (antagonists & inhibitors)