Modulation of gene expression in endothelial cells by hyperlipaemic postprandial serum from healthy volunteers

Abstract

A single high-fat challenge induces plasmatic pro-inflammatory and pro-oxidative responses in the postprandial state, even in healthy men. This period is also associated with vascular endothelial dysfunction, which is an early event in the development of cardiovascular diseases. However, knowledge about the mechanisms involved in postprandial hyperlipaemia-induced endothelial dysfunction is sparse. An objective of our study was to characterize the behaviour and gene expression of vascular endothelial cells exposed to postprandial hyperlipaemic sera. Human umbilical vein endothelial cells (HUVECs) were cultured in media containing 10% serum from healthy men withdrawn either before or 4 h after a high-fat challenge. Endothelial cell proliferation, adhesion and migration were then assessed. The transcriptomic profiles of endothelial cells exposed to pre and postprandial sera were also compared. Exposure to postprandial hyperlipaemic sera significantly decreased HUVEC proliferation when compared to preprandial serum (P < 0.0001), while no changes in migration or endothelial/monocyte interactions were observed. The transcriptomic analysis revealed changes in the expression of 675 genes, of which 431 have a known function. Among them, a set of differentially expressed genes was linked to cell cycle regulation and apoptosis and are regulated in favour of cell cycle arrest or death. This result was confirmed by measuring the induction of apoptosis after postprandial sera exposure (P = 0.011). Taken together, the transcriptomic results and pathway analysis showed that postprandial serum promotes apoptosis in HUVECs, potentially through the activation of the p53 network. We conclude that upon postprandial serum exposure, vascular endothelial cells transcriptionally regulate genes involved in the control of cell cycle and death to favour growth arrest and apoptosis. These findings support the hypothesis that postprandial hyperlipaemia is associated with vascular dysfunction and offer new insights into the mechanisms involved.

Electronic supplementary material: The online version of this article (doi:10.1007/s12263-010-0166-x) contains supplementary material, which is available to authorized users.

Keywords: Apoptosis atherogenesis; Nutrigenomics; Postprandial hyperlipaemia; Vascular endothelial cells.

Fig. 1

Changes in postprandial plasma lipid concentrations after high-fat ingestion. The mean and standard deviation of plasma (A) cholesterol, (B) triacylglycerols (TG) and (C) free fatty acids (FFA) during an 8-h postprandial period are shown. Values are means ± SD, n = 7. **P < 0.01

Fig. 2

Changes in HUVEC proliferation after preprandial (0 h) or postprandial (4 h) sera exposure. The means and standard deviations of cell numbers are shown. Values are means ± SD, n = 36. ***P < 0.0001

Fig. 3

Changes in apoptosis induction in HUVECs after preprandial (T0) or postprandial (T4) sera exposure. Cell death was assessed using a cell death detection ELISA kit (Roche), which detects the amount of cleaved DNA/histone complexes. Values are means ± SD, n = 5. **P = 0.011