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F12511(S)-2',3',5'-trimethyl-4'-hydroxy-alpha-dodecylthio-alpha-phenylacetanilide (F12511) is a new Acyl-CoA cholesterol acyltransferase (ACAT) inhibitor that not only reduces the plasma cholesterol levels but also has anti-atherosclerotic actions in animals models. The study's aim was to analyze if F12511 may directly modify the ability of tumor necrosis factor--alpha (TNF-alpha)-incubated bovine aortic endothelial cells (BAEC) to express endothelial nitric oxide synthase (eNOS) protein and inflammatory-related proteins such as platelet endothelial cell adhesion molecule (PECAM) and CD40 ligand (CD40L). The addition of increasing concentrations of F12511 (10 to 10 mol/L) failed to modify the level of eNOS protein expressed in control BAEC. TNF-alpha (10 ng/mL) reduced the expression of eNOS protein. In TNF-alpha--incubated BAEC, F12511 protected eNOS expression in a concentration-dependent manner. TNF-alpha stimulated the expression of both CD40L and PECAM in cultured BAEC. F12511 (10 mol/L) failed to modify the expression of CD40L and PECAM in control and TNF-alpha-incubated BAEC. Reverse transcriptase polymerase chain reaction showed a marked expression of the ACAT-2 isoform and absent of expression of the ACAT-1 isoform in BAEC. The presence of ACAT-2 isoform in BAEC was further confirmed by Western blot. F12511 failed to modify the expression of the proinflammatory associated proteins PECAM and CD40L in the endothelium but protected eNOS expression in the endothelial cells exposed to inflammatory conditions.

The major CRP (C-reactive protein) receptor on leucocytes has been identified as the low-affinity IgG receptor Fcgamma receptor II (CD32). Our aim was to assess whether inflammation may modify the presence of the CD32 receptor in BAEC (bovine aortic endothelial cells). Confocal microscopy experiments showed a weak expression of the CD32 receptor in control BAEC that was slightly increased by 10 microg/ml CRP. Incubation of BAEC with TNF-alpha (tumour necrosis factor-alpha) did not modify the fluorescence signal of CD32. Addition of CRP to TNF-alpha-incubated BAEC enhanced the fluorescence signal of the CD32 receptors. The CD32 receptors showed a perinuclear cytoplasmic localization in BAEC. An alteration of the NO (nitric oxide)-dependent vasorelaxation has been defined as endothelial dysfunction. Endothelial dysfunction has been associated with the presence of superoxide anion and with a reduction in the expression of the eNOS (endothelial NO synthase). A concentration of CRP similar to that detected in patients with cardiovascular risk (10 microg/ml) failed to modify the generation of superoxide anion stimulated by TNF-alpha. Western blot experiments showed that TNF-alpha decreased the expression of the eNOS protein, which was partially protected by treatment with 10 microg/ml CRP. The protective effect of 10 microg/ml CRP on eNOS expression in TNF-alpha-incubated BAEC was prevented by an antibody against CD32 receptors. In conclusion, the present results suggest that, although CRP has been associated with inflammation, CRP may protect the expression of eNOS protein against pro-inflammatory mediators such as TNF-alpha.