Format

Send to:

Choose Destination
See comment in PubMed Commons below
Cardiovasc Res. 2001 Apr;50(1):97-107.

Loss of cyclin A and G1-cell cycle arrest are a prerequisite of ceramide-induced toxicity in human arterial endothelial cells.

Author information

  • 1Department of Cardiology and Cardiovascular Research, Medizinische Klinik III, Otfried-Mueller-Str. 10, 72076, Tübingen, Germany. ioakim_s@hotmail.com

Abstract

BACKGROUND:

Ceramide is an important messenger of TNF- and lipid-induced apoptosis. We previously demonstrated the adverse effect of TNF in the process of reendothelialization as well as the dependence of its effect on cell-cycle regulation. The current study was designed to investigate the linkage between ceramide induced toxicity and growth arrest in human endothelial cells.

METHODS AND RESULTS:

Cultured human arterial endothelial cells (HAEC) served as an in-vitro model to test the cellular effects of C2-ceramide (C2). C2-induced cell death in HAECs occurred time- and dose-dependently. The LD(50) in subconfluent cells was three times lower than in confluent cell layers (25 vs. 75 microM). C2 caused up to 70% inhibition of BrdU and [3H]thymidine incorporation at non-toxic concentrations as a result of G1 cell-cycle arrest. Downregulation of cyclin A and p21(Cip1/Waf1) protein expression was observed independently of C2-toxicity, while expression of other cell-cycle regulatory genes was not affected. Inhibition of cyclin A protein expression by sequence-specific antisense-oligonucleotides was paralleled by significant growth-inhibition. The protein phosphatase inhibitor okadaic acid induced endothelial cell proliferation, which was completely abrogated by C2. In contrast, aphidicolin-synchronized endothelial cells demonstrated elevated cyclin A levels along with 30% higher BrdU-incorporation and 70% less C2-toxicity. G1-arrested cells, however, showed significantly enhanced C2-toxicity, lack of cyclin A expression and induction of uncleaved caspase-3 (CPP32).

CONCLUSIONS:

Ceramide abrogates endothelial cell proliferation independently of apoptosis or necrosis at low concentrations (<or=10 microM) through loss of cyclin A expression with subsequent G1 cell-cycle arrest. Synchronization of HAECs in S-phase with aphidicolin overcomes C2-induced G1-arrest and partially blocks ceramide toxicity. These findings demonstrate the dependence of ceramide toxicity on cell cycle regulation, suggesting a strong bidirectional relationship between cell-cycle control and cell death in vessel biology.

PMID:
11282082
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk