Cardiovascular Research Advance Access originally published online on February 4, 2008
Cardiovascular Research 2008 78(3):563-571; doi:10.1093/cvr/cvn024
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In human endothelial cells rapamycin causes mTORC2 inhibition and impairs cell viability and function
1 Department of Experimental Medicine, Unit of General and Clinical Pathology, University of Parma, Via Volturno 39, 43100 Parma, Italy
2 Department of Heart Surgery, Clinical Research Unit in Aterothrombosis, University of Milano, Centro Cardiologico Fondazione Monzino I.R.C.C.S., Milano, Italy
3 Laboratory of Hematology and BMT Center, University of Parma, Italy
4 Department of Pharmacology, Johannes Gutenberg University, Mainz, Germany
* Corresponding author. Tel: +39 0521 033784; fax: + 39 0521 033742. E-mail address: valeria.dallasta{at}unipr.it
Aim: Drug-eluting stents are widely used to prevent restenosis but are associated with late endothelial damage. To understand the basis for this effect, we have studied the consequences of a prolonged incubation with rapamycin on the viability and functions of endothelial cells.
Methods and results: Human umbilical vein or aorta endothelial cells were exposed to rapamycin in the absence or in the presence of tumour necrosis factor 
(TNF). After a 24 h-incubation, rapamycin (100 nM) caused a significant cell loss associated with the increase of both apoptosis and necrosis, as quantified by propidium iodide staining, caspase 3 activity, and lactate dehydrogenase release. Rapamycin also impaired cell mobility, as assessed by a wound test, and promoted the formation of actin stress fibres, as determined with confocal microscopy. Moreover, the inhibitor prolonged TNF-dependent E-selectin induction, inhibited endothelial nitric oxide synthase expression at both mRNA (quantitative real-time polymerase chain reaction) and protein level (enzyme-linked immunosorbent assay and western blot), and lowered bioactive nitric oxide output (RFL-6 reporter cell assay). Under the conditions adopted, rapamycin inhibited both mammalian target-of-rapamycin complexes (mTORC1 and mTORC2), as indicated by the reduced amount of raptor and rictor bound to mTOR in immunoprecipitates and by the marked hypophosphorylation of protein S6 kinase I (p70S6K) and Akt, determined by western blotting. The selective inhibition of mTORC1 by AICAR did not affect endothelial viability.
Conclusion: A prolonged treatment with rapamycin impairs endothelial function and hinders cell viability. Endothelial damage seems dependent on mTORC2 inhibition.
KEYWORDS mTOR; Apoptosis; TNFalpha; Nitric oxide; Restenosis
Time for primary review: 53 days
The two first authors contributed equally
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  E. Raichlin, A. Prasad, W. K. Kremers, B. S. Edwards, C. S. Rihal, A. Lerman, and S. S. Kushwaha Sirolimus as primary immunosuppression is associated with improved coronary vasomotor function compared with calcineurin inhibitors in stable cardiac transplant recipients Eur. Heart J., June 1, 2009; 30(11): 1356 - 1363. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. W. Ronellenfitsch, D. P. Brucker, M. C. Burger, S. Wolking, F. Tritschler, J. Rieger, W. Wick, M. Weller, and J. P. Steinbach Antagonism of the mammalian target of rapamycin selectively mediates metabolic effects of epidermal growth factor receptor inhibition and protects human malignant glioma cells from hypoxia-induced cell death Brain, June 1, 2009; 132(6): 1509 - 1522. [Abstract] [Full Text] [PDF]
|
|