http://repub.eur.nl/res/aut/11727/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/29697/ 2008-11-06T00:00:00Z Expression of hepatic lipase (HL) in the liver is reduced during prolonged fasting. This effect is mainly mediated via catecholamines, which signal through elevation of Cai2+as well as cAMP. We have studied the effect of cAMP on HL expression in cell culture. Overnight incubation of HepG2 cells with 10-300 μM 8-bromo-cyclic AMP resulted in a dose-dependent, up to 50% reduction in secretion of HL, but had no effect on secretion of α1-antitrypsin or overall protein synthesis. HL mRNA levels were decreased 1.5 fold, as determined by semi-quantitative and real-time RT-PCR. In HepG2 cells transiently transfected with human HL (-685/+13) or rat HL (-446/+9) promoter-reporter constructs, cAMP induced a similar dose-dependent suppression of HL promoter activity. cAMP responsiveness in HepG2 cells was mediated by a conserved 10-bp response element at -45/-36, that represents a potential binding site for CCAAT/enhancer-binding protein beta (C/EBPβ). cAMP reduced expression of the 45 kDa C/EBPβ protein and binding of C/EBPβ to the proximal promoter region of the human HL gene by 50%, as determined by immunoblotting and chromatin immunoprecipitation assay, respectively. In human H295R adrenocortical cells, cAMP failed to suppress HL promoter activity, and only slightly reduced C/EBPβ expression. We conclude that the fall in HL expression during prolonged fasting may be mediated through elevation of cAMP and lowering of C/EBPβ expression. http://repub.eur.nl/res/pub/28961/ 2008-09-01T00:00:00Z Cholesteryl ester transfer protein (CETP) and hepatic lipase (HL) are two HDL modifying proteins that have both pro- and anti-atherogenic properties. We hypothesized that CETP and HL synergistically affect HDL cholesterol and atherosclerotic risk. To test our hypothesis, we analysed the genotype frequencies of CETP Taq1B (rs708272) and LIPC-514C/T (rs1800588) polymorphisms in male coronary artery disease patients (CAD; n = 792) and non-symptomatic controls (n = 539). Cases and controls had similar allele frequencies, but the occurrence of the combined genotypes differed (p = 0.027). In CAD patients, 1.3% had the CETP-B2B2/LIPC-TT genotype, with only 0.2% in controls (p = 0.033). The presence of the CETP lowering B2 allele and the HL lowering LIPC-T allele synergistically increased HDL cholesterol from 0.87 ± 0.19 mmol/L in the B1B1/CC (n = 183) to 1.21 ± 0.25 mmol/L in the B2B2/TT carriers (n = 10). The B1B1/CC carriers had an increased CAD risk (OR 1.4; p = 0.025). Despite their high HDL cholesterol, the B2B2/TT individuals also had an increased CAD risk (OR 3.7; p = 0.033). In a 2-year follow up, the loss of coronary artery lumen diameter in these patients was higher than in all other patients combined (0.34 ± 0.70 versus 0.10 ± 0.29 mm; p = 0.044). We conclude that a high HDL cholesterol does not protect against coronary artery disease when associated with combined CETP- and HL-lowering gene variants. http://repub.eur.nl/res/pub/8178/ 2006-12-20T00:00:00Z