Anne-Marie Batt

Astroglial CYP1B1 up-regulation in inflammatory/oxidative toxic conditions: IL-1β effect and protection by N-acetylcysteine

The present work aims to determine the relevance of an astrocytoma cell line U373 MG, for assessing the role of some astroglial cytochrome P450 in neurotoxicity and neuroprotection. CYP1B1, CYP2C8, CYP2C9, CYP2D6, CYP2J2, CYP2E1 and CYP4A11 mRNA were detected by reverse transcriptase-polymerase chain reaction in control U373 MG cell cultures. Among them we focused on CYP1B1 expression. After 48 h treatment with a range of concentrations of interleukin-1beta (1, 5, 10 ng/ml) used to simulate stress conditions, CYP1B1 mRNA expression was enhanced in a dose-dependent way. This increased expression was followed 24 h later by an increase in protein level, determined by Western-blot. N-acetylcysteine (NAC) partially inhibited this effect both on the mRNA and protein levels. As CYP1B1 activates procarcinogenic compounds to reactive metabolites, an increase in this P450 isoform will participate to toxic consequences of an inflammatory/oxidative stress. NAC will prevent this deleterious effect.

Cytochromes P450 are differently expressed in normal and varicose human saphenous veins: Linkage with varicosis

1. The expression of cytochrome P450 (CYP) enzymes and cyclo‐oxygenases (COX) was investigated in human saphenous veins by reverse transcription–polymerase chain reaction analysis. Non‐varicose veins were obtained from patients undergoing aortocoronary bypass grafting, whereas varicose veins were obtained from patients undergoing stripping removal of varicose saphenous veins.

Control of apolipoprotein E secretion by 25-hydroxycholesterol and proinflammatory cytokines in the human astrocytoma cell line CCF-STTG1

During the last few years the increased presence of proinflammatory cytokines and oxidation products in Alzheimers disease (AD) has been largely described. Oxysterols, formed by hydroxylation of cholesterol, occur naturally in the brain and are increased in the serum of AD patients. Of these oxysterols, 25-hydroxycholesterol is the most potent regulator of gene transcription. It stimulates the synthesis of apolipoprotein E (apo E) in macrophages. Apo E plays a major role in the brain as a phospholipid and cholesterol carrier molecule in compensatory synaptogenesis. Cytokines might also be able to modulate apo E expression. Accordingly, this study examined the control of apo E secretion by several proinflammatory cytokines and oxysterols in the human astrocytoma cell line CCF-STTG1. A time-dependent stimulation of apo E secretion by 25-hydroxycholesterol was observed. Among several cytokines tested, only tumor necrosis factor (TNF)-α inhibited apo E secretion in basal conditions in CCF-STTG1 human astrocytoma cells. In the presence of 25-hydroxycholesterol, TNF-α reduced apo E secretion by 80%, while interleukins (IL) IL-1β, IL-6, and IL-2 had no significant effects. In Alzheimers disease, the increase in the concentrations of cytokines and the concomitant decrease of cholesterol concentration in the brain could contribute jointly to reduce apo E concentration, and in doing so accelerate neurodegeneration. Surprisingly, oxysterols would be able to limit this phenomenon.

U373-MG response to interleukin-1β-induced oxidative stress

Oxidative stress has been involved in various neurological disorders and, in the central nervous system, astrocytes represent the cell type that contributes to neuroprotection via glutathione (GSH) metabolism, GSH-metabolizing enzymes like γ-glutamyltransferase (GGT), and apoE secretion. In this study, using IL-1β, a proinflammatory and prooxidant cytokine that is increased in numerous pathological situations, cells of astrocytoma cell line U373-MG were exposed to an oxidative stress, leading to c-Jun and c-Fos activation. IL-1β decreased both GGT activity and intracellular GSH content and increased apoE secretion, initiating astroglial response to injury. We observed that antioxidants inhibit IL-1β effects on c-Jun and c-Fos proteins, GGT activity and the GSH pool but not on apoE secretion. Our results allow us to conclude that neurological disorders associated with an IL-1β-induced oxidative stress could be, at least experimentally, reversible in the presence of one antioxidant, N-acetylcysteine.

Pharmacogénomique et pharmacoprotéomique: Stratégie pour les médicaments cardio-vasculaires

The development of personalized medicine will require improved knowledge of biological variability, particularly concerning the important impact of each individuals genetic makeup. A five-step strategy can be followed when trying to identify genes and gene products involved in differential responses to cardiovascular drugs: 1) Pharmacokinetic-related genes and phenotypes; (2) Pharmacodynamic targets, genes and products; (3) Cardiovascular diseases and risks depending on specific or large metabolic cycles; (4) Physiological variations of previously identified genes and proteins; (5) Environmental influences on them. After summarizing the most well known genes involved in drug metabolism, we used statins as an example. In addition to their economic impact, statins are generally considered to be of significant importance in terms of public health. Individuals respond differently to these drugs depending on multiple polymorphisms. Applying a pharmacoproteomic strategy, it is important to use available information on peptides, proteins and metabolites, generally gene products, in each of the five steps. A profiling approach dealing with genomics as well as proteomics is useful. In conclusion, the ever growing volume of available data will require an organized interpretation of variations in DNA and mRNA as well as proteins, both on the individual and population level.Resume La therapeutique personnalisee est basee sur une meilleure connaissance de la variabilite biologique, en prenant en compte l’importance de la genetique. Afin d’identifier les genes ainsi que leurs produits, impliques dans la reponse differentielle aux medicaments a visee cardio-vasculaire nous proposons une strategie en cinq etapes qui considere : 1) les genes et phenotypes lies a la pharmacocinetique ; 2) les genes et produits (cibles therapeutiques) lies a la pharmacodynamie ; 3) les maladies et risques cardio-vasculaires vus sous l’angle des cycles metaboliques specifiques en cause ; 4) les variations physiologiques des genes et proteines precedemment identifiees ; 5) et l’influence de l’environnement. Apres avoir pris comme exemple des genes impliques dans le metabolisme des medicaments, nous nous interesserons aux statines, consideres comme etant des medicaments tres importants d’un point de vue de sante publique. Il existe une grande variabilite de la reponse a ces medicaments notamment a cause de plusieurs polymorphismes dans les genes cibles de ces hypolipemiants. Par ailleurs, a chacune des cinq etapes de la strategie pharmacogenomique, nous avons en plus de l’information genetique, besoin d’utiliser les informations disponibles au sujet des peptides, proteines et metabolites, qui sont generalement les produits des genes. Une approche de type profil est necessaire et utile en genomique mais aussi en proteomique. En conclusion, le nombre important de donnees va plus que jamais rendre necessaire une interpretation integree des variations de l’ADN, de l’ARN messager ainsi que des proteines au niveau individuel et de la population generale pour esperer d’une facon cliniquement simple, adapter un medicament a chaque individu.