title: Atorvastatin sensitises vascular smooth muscle cells, but not endothelial cells, to TNF-α-induced cell death.
abstract: OBJECTIVE
  Stimuli activating vascular smooth muscle cell death can constrain the neointimal response to arterial damage and prevent vascular thickening. Conversely, endothelial cell death increases endothelial dysfunction and thrombosis risk. We investigated the combined effect of atorvastatin and TNF-α on vascular cell death.
  
  
  RESULTS
  Cell death was investigated in cultures of human aortic smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs). Atorvastatin downregulated NF-κB and enhanced JNK activity and cell death in VSMC cultured with TNF- α. In the absence of TNF-α, percentages (mean and StDev) of annexin V positive cells were 17.4 ± 6.6%, 19.3 ± 5.9%, 22.9 ± 9.4% and 35.0 ± 20.0 % with 0, 1, 3 and 10 µM atorvastatin, respectively. The cytotoxic effect of statin was significant at the highest dose of 10 μM (p=0.001). In the presence of TNF-α, percentages of annexin V positive cells were 27.1 ± 10.6%, 34.2 ± 8.5%, 37.4 ± 14.6, and 54.1 ± 20.0% with 0, 1, 3 and 10 µM atorvastatin, respectively. The cytotoxic effect of statin was significant at each dose used (p≤0.02), in the presence of TNF-α. The cell death sensitising effect of atorvastatin was apparently mediated by down modulation of PKCβ activity, because it was reproduced by the specific PKCβ inhibitor LY317615 and prevented by the PKC activator phorbol-12-myristate-13-acetate (PMA). This effect was cell context dependent because it was not observed in HUVECs. PKCβ was found to be constitutively active in VSMCs but not in HUVECs, thereby explaining the differential effect among the two cell types. Measurement of phosphoPKCβ protein levels in arterial specimens confirmed increased activation of this kinase in the smooth muscle layer, in comparison with endothelium. We show that PKCβ provides survival signals to vascular smooth muscle cells and not the endothelium.
  
  
  CONCLUSIONS
  Our study suggests that atorvastatin enhances TNF-α-induced cell death in vascular smooth muscle- but not endothelial - cells; by a cell-context-dependent mechanism, involving PKCβ inhibition.
authors.affiliation: Invasive Cardiology Unit, Pineta Grande Hospital, Castelvolturno, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Giordano
authors.forename: Simona
authors.initials: S
authors.lastname: Romano
authors.forename: Giovanna
authors.initials: G
authors.lastname: Nappo
authors.forename: Stefano
authors.initials: S
authors.lastname: Messina
authors.forename: Michele
authors.initials: M
authors.lastname: Polimeno
authors.forename: Nicola
authors.initials: N
authors.lastname: Corcione
authors.forename: Gaetano
authors.initials: G
authors.lastname: Cali
authors.forename: Paolo
authors.initials: P
authors.lastname: Ferraro
authors.forename: Mario
authors.initials: M
authors.lastname: Monaco
authors.forename: Nicola
authors.initials: N
authors.lastname: Zambrano
authors.forename: Maria Fiammetta
authors.initials: MF
authors.lastname: Romano
mesh_terms: D000069059:Atorvastatin; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D006538:Heptanoic Acids / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D064546:Protein Kinase C beta; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D020536:Enzyme Activators; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D016328:NF-kappa B; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; D014409:Tumor Necrosis Factor-alpha; D000069059:Atorvastatin; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D048031:JNK Mitogen-Activated Protein Kinases