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November 1992 - December 2012
January 1988 - December 1990
August 1990 - October 1992
College de France, INSERM 36, Paris, France
Position
- Invited Researcher
Publications
Publications (61)
This Special Issue on the topic of Steroid and Sterol Signaling: Promiscuity and Diversity, dwells on the growing realization that the 'one ligand, one binding site' and 'one enzyme, one reaction' concepts are out of date. Focusing on cytochromes P450 (CYP), hydroxysteroid dehydrogenases (HSDs), and related enzymes, the Special Issue highlights tha...
Aging is accompanied by increasing vulnerability to pathologies such as atherosclerosis (ATH) and Alzheimer disease (AD). Are these different pathologies, or different presentations with a similar underlying pathoetiology?
Both ATH and AD involve inflammation, macrophage infiltration, and occlusion of the vasculature. Allelic variants in common gen...
11β-Hydroxysteroid dehydrogenase (11β-HSD) catalyses the inter-conversion of corticosterone and inert 11-dehydrocorticosterone. The NADP(H)-dependent type 1 isozyme is widely distributed and acts predominantly as a reductase in vivo, regenerating active glucocorticoid (1). In contrast, 11β-HSD-2 is a higher-affinity, NAD-dependent, exclusive dehydr...
The potent vasoconstrictor endothelin-1 (ET-1), acting on the endothelin-A (ETA) receptor, promotes intimal lesion formation following vascular injury. The endothelin-B (ETB) receptor, which mediates nitric oxide release and ET-1 clearance in endothelial cells, may moderate lesion formation, but this is less clear. We used selective ET receptor ant...
This study characterized the actions of the newly synthesized PAF precursor 1-hexadecyl-2-alkylcarbamoyl-glycerol (HAG) on blood pressure (BP) in male spontaneously hypertensive rats (SHR), SHR-stroke prone (SHRSP) and Wistar rats with 1-kidney 1-clip (1K1C) renovascular hypertension used as experimental models of human primary and secondary hypert...
Salt sensitivity of blood pressure is an independent risk factor for cardiovascular morbidity. Mechanistically, abnormal mineralocorticoid action and subclinical renal impairment may blunt the natriuretic response to high sodium intake, causing blood pressure to rise. 11β-Hydroxysteroid dehydrogenase type 2 (11βHSD2) controls ligand access to the m...
Mineralocorticoid receptor (MR) activation is proinflammatory and proatherogenic. Antagonism of MR improves survival in humans with congestive heart failure caused by atherosclerotic disease. In animal models, activation of MR exacerbates atherosclerosis. The enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) prevents inappropriate activatio...
Inactivation of endothelin B receptors (ETB), either through selective pharmacological antagonism or genetic mutation, increases the circulating concentration of endothelin-1 (ET-1), suggesting ETB plays an important role in clearance of this peptide. However, the cellular site of ETB-mediated clearance has not yet been determined. We have used a n...
We hypothesised that the potential protective effects of endothelial ET(B) are important in limiting pulmonary vascular muscularisation, vasoconstriction and the development of pulmonary arterial hypertension in response to hypoxia.
EC-specific ET(B) knockout mice (EC ET(B)(-/-)) and control mice (ET(B)(f/f)) were subjected to hypobaric hypoxic (10...
The collecting duct (CD) endothelin (ET) system regulates blood pressure (BP) and Na excretion. CD-specific knockout (KO) of ET-1 causes hypertension, CD-specific KO of the ETA receptor does not alter BP, while CD-specific KO of the ETB receptor increases BP to a lesser extent than CD ET-1 KO. These findings suggest a paracrine role for CD-derived...
Collecting duct (CD)-derived endothelin-1 (ET-1) inhibits renal Na reabsorption and its deficiency increases blood pressure (BP). The role of CD endothelin B (ETB) receptors in mediating these effects is unknown. CD-specific knockout of the ETB receptor was achieved using an aquaporin-2 promoter-Cre recombinase transgene and the loxP-flanked ETB re...
Endothelin B receptors in different tissues regulate diverse physiological responses including vasoconstriction, vasodilatation, clearance of endothelin-1, and renal tubular sodium reabsorption. To examine the role of endothelial cell endothelin B receptors in these processes, we generated endothelial cell-specific endothelin B receptor knockout mi...
The use of reporter genes such as beta-galactosidase and green fluorescent protein is a powerful molecular tool for the visualization of in-vivo gene expression. In this paper, we describe the generation of mice that possess a beta-galactosidase reporter gene introduced into the endothelin-B receptor locus by homologous recombination in embryonic s...
The resolution of inflammation is dependent on recognition and phagocytic removal of apoptotic cells by macrophages. Receptors for apoptotic cells are sensitive to degradation by human neutrophil elastase (HNE). We show in the present study that HNE cleaves macrophage cell surface CD14 and in so doing, reduces phagocytic recognition of apoptotic ly...
Atherosclerosis is a chronic inflammatory disease affecting arterial vessels. Strategies to reduce the inflammatory responses of endothelial cells and macrophages may slow lesion development and prevent complications such as plaque rupture. The human protease human neutrophil elastase (HNE), oxidized low density lipoprotein, LPS, and TNF-alpha were...
Glucocorticoids affect a wide range of processes in the brain, altering neurotransmission, electrophysiological activity, metabolism, cell division, and death. These actions are mediated by corticosteroid receptors (glucocorticoid and mineralocorticoid) that modify transcriptional activity of target genes. The amount of steroid available to activat...
Glucocorticoids affect a wide range of processes in the brain, altering neurotransmission, electrophysiological activity, metabolism, cell division, and death. These actions are mediated by corticosteroid receptors (glucocorticoid and mineralocorticoid) that modify transcriptional activity of target genes. The amount of steroid available to activat...
Glucocorticoids (GCs) induce surfactant synthesis in the late foetal lung. Deficient GC action causes respiratory distress syndrome (RDS). 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts inert cortisone (11-dehydrocorticosterone in rodents) into active cortisol (corticosterone), thus amplifying intracellular GC action. Reduction o...
The number of cardiovascular publications featuring gene expression profiling technologies is growing rapidly. This article introduces four profiling techniques; serial analysis of gene expression, differential display, subtractive hybridisation and DNA microarrays. Illustrations of their application towards cardiovascular research are given and th...
11beta-Hydroxysteroid dehydrogenase (11betaHSD) isozymes catalyze the interconversion of active and inactive glucocorticoids, allowing local regulation of corticosteroid receptor activation. Both are present in the vessel wall; here, using mice with selective inactivation of 11betaHSD isozymes, we test the hypothesis that 11betaHSDs influence vascu...
A novel inbred rat model with inducible hypertension has been generated using a renin transgene under the transcriptional
control of the cytochrome P450, Cyp1a1promoter. The degree and duration of hypertension are regulated tightly by administration of the natural xenobiotic indole-3
carbinol and can be readily reversed. Induction experiments revea...
Time for primary review 26 days.
There is a widely held view that function of the kidney is the key to understanding human essential hypertension. Indeed, all of the currently recognised human monogenic causes of hypertension reflect abnormalities in the genes that determine ion transport in the distal portion of the nephron [1]. It is also recog...
11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) intracellularly regenerates active corticosterone from circulating inert 11-dehydrocorticosterone (11-DHC) in specific tissues. The hippocampus is a brain structure particularly vulnerable to glucocorticoid neurotoxicity with aging. In intact hippocampal cells in culture, 11beta-HSD-1 acts a...
The glucocorticoid metabolising enzymes, 11beta-hydroxysteroid dehydrogenases (11beta-HSD), play a critical role in determining the availability of glucocorticoids to activate their receptors and hence modulate target gene transcription. There are two isozymes, 11beta-HSD-1 and -2, which act in opposing directions. 11beta-HSD-2 acts as a dehydrogen...
11beta-Hydroxysteroid dehydrogenases (11beta-HSDs) catalyze interconversion of active corticosterone and inert 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors in vivo. 11beta-HSD type 1 is a reductase, locally regenerating active glucocorticoids. To explore the role of this isozyme in the brain, we examine...
Knockout (KO) models have provided important insights into the function of many receptors and signalling molecules. However, analysis of endothelin (ET) receptor knockouts has been complicated by the development of lethal phenotypes. In this paper, we present our strategy for examining endothelin-B- (ET(B)) receptor function in the context of other...
Genetic background has a major influence on the manifestation of multifactorial diseases such as hypertension in which severe complications may be caused through an interaction with additional factors, which may be genetically determined. We have previously described a genetic model of malignant hypertension (MH) in rats carrying the mouse Ren2 gen...
Intracellular interconversion of active 11-hydroxy glucocorticoids (cortisol, corticosterone) and inert 11 keto products (cortisone, 11-dehydrocorticosterone) by 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes has emerged as a new, potent mechanism of regulation of glucocorticoid action. 11β-hydroxysteroid dehydrogenase type 1 is a widespread, N...
Deficiency of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in humans leads to the syndrome of apparent mineralocorticoid excess (SAME), in which cortisol illicitly occupies mineralocorticoid receptors, causing sodium retention, hypokalemia, and hypertension. However, the disorder is usually incompletely corrected by suppression of corti...
Glucocorticoid hormones, acting via nuclear receptors, regulate many metabolic processes, including hepatic gluconeogenesis. It recently has been recognized that intracellular glucocorticoid concentrations are determined not only by plasma hormone levels, but also by intracellular 11beta-hydroxysteroid dehydrogenases (11beta-HSDs), which interconve...
Glucocorticoid hormones, acting via nuclear receptors, regulate many metabolic processes, including hepatic gluconeogenesis.
It recently has been recognized that intracellular glucocorticoid concentrations are determined not only by plasma hormone
levels, but also by intracellular 11β-hydroxysteroid dehydrogenases (11β-HSDs), which interconvert act...
By inactivating potent glucocorticoid hormones (cortisol and corticosterone), 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta-HSD2) plays an important role in the placenta by controlling fetal exposure to maternal glucocorticoids, and in aldosterone target tissues by controlling ligand access to co-localized glucocorticoid and mineralocorticoi...
Glucocorticoids play important roles in development and 'fetal programming'. Fetal exposure to excess glucocorticoids reduces birth weight and causes later hypertension. To investigate these processes further we have determined the detailed category of 11 beta-hydroxysteroid dehydrogenase type2 (11 beta-HSD2, which potently inactivates glucocortico...
Most of the known effects of aldosterone are mediated by the mineralocorticoid receptor, an intracellular receptor belonging to the steroid/thyroid hormone/retinoic acid receptor superfamily. We determined the genomic structure of the human MR (hMR) and identified 10 exons in the gene, including two exons (1 alpha and 1 beta) that encode different...
A genetic model of malignant phase hypertension in rats is described which closely parallels the natural history of untreated human malignant phase hypertension. Although the factors initiating transition from essential hypertension to the accelerated phase in humans remain unknown, we report the characteristics of a genetically determined and repr...
Several genetic loci involved in blood pressure regulation have recently been localized in experimental models of hypertension, but the manner in which they influence blood pressure remains unknown. Here, we report a study of the Lyon hypertensive rat strain showing that different loci are involved in the regulation of steady-state (diastolic press...
Essential hypertension is a common human disease believed to result from the interplay of multiple genetic and environmental determinants. In genetic studies of two large panels of hypertensive sibships from widely separated geographical areas, we obtained evidence of genetic linkage between the angiotensinogen gene (AGT) and hypertension, demonstr...
The activity of transport adenosine triphosphatases (ATPases) in saponin-treated erythrocytes as well as the passive membrane permeability for 86Rb+ (K+), 45Ca2+ uptake (in the presence of orthovanadate) and the rate of Na(+)-H+ exchange in intact erythrocytes were studied in spontaneously hypertensive rats (SHR), Wistar-Kyoto (WKY) and Brown-Norwa...
Twenty-six F2 hybrids between spontaneously hypertensive (SHR) and normotensive control (WKY) rats [(SHR x WKY)F2] were segregated according to their c-src genotype into SS and WW homozygous groups, corresponding to SHR or WKY and a WS heterozygous group. The Na,K cotransport in erythrocytes in the WW group was equal to that of WKY and differed sig...
Osmotic swelling of human and rat erythrocytes does not induce regulatory volume decrease. Regulatory volume increase was observed in shrunken erythrocytes of rats only. This reaction was blocked by the inhibitors of Na+/H+ exchange. Cytoplasmic acidification in erythrocytes of both species increases the amiloride-inhibited component of22Na influx...
Interstrain restriction fragment length polymorphism was detected after Southern blot hybridization of spontaneously hypertensive (SHR) and control (WKY) rat DNA digested by Bam HI restrictase with a v-fos probe. The SHR genome was characterized by an additional minor band of 4.0 kb. Other restriction fragment length polymorphism was revealed in th...
Certain manifestations of alterations of membrane cytoskeleton, protein kinase C activity, and ion transport were revealed in erythrocytes of patients with essential hypertension: 1) the average volume of erythrocytes is reduced by 4%; 2) about 7% of the total number of erythrocytes is represented by cup-shaped forms compared with 1.5 to 3.0% in th...