No / Human aging involves a gradual decrease in cellular integrity that contributes to multiple complex disorders such as neurodegenerative disorders, cancer, diabetes, and cardiovascular diseases. Genome-wide association studies (GWAS) play a key role in discovering genetic variations that may contribute towards disease vulnerability. However, mostly disease-associated SNPs lie within non-coding part of the genome; majority of the variants are also present in linkage disequilibrium (LD) with the genome-wide significant SNPs (GWAS lead SNPs). Overall 600 SNPs were analyzed, out of which 291 returned RegulomeDB scores of 1-6. It was observed that just 4 out of those 291 SNPs show strong evidence of regulatory effects (RegulomeDB score < 3), while none of them includes any GWAS lead SNP. Nevertheless, this study demonstrates that by combining ENCODE project data along with GWAS reported information will provide important insights on the impact of a genetic variant-moving from GWAS towards understanding disease pathways. It is noteworthy that both genome-wide significant SNPs as well as the SNPs in LD must be considered for future studies; this may prove to be crucial in deciphering the potential regulatory elements involved in complex disorders and aging in particular.

Qualitativ unterschiedliche genomische und nichtgenomische Mechanismen vermitteln die starken anti-inflammatorischen und immunmdulatorischen Eigenschaften der Glucocorticoide (GC). Der genomisch vermittelte Mechanismus ist bereits gut untersucht und dokumentiert, während der nichtgenomisch vermittelte Mechanismen noch einen Gegenstand vielseitiger Untersuchungen darstellt. Wir haben uns daher die Frage gestellt, ob Beclometason und Clobetasol besonders geeignet für die topische Applikation sind, weil sie sich in ihrem Wirkungsspektrum von systemisch zu applizierenden GC wie Dexamethason unterscheiden. Wir verglichen dazu die Effekte auf den Sauerstoffverbrauch mittels der Clark-Elektrode (nichtspezifisch nichtgenomischer Mechanismus), auf die IL-6-Synthese mittels ELISA (genomischer Mechanismus) und auf die Apoptose mittels Durchflusszytometrie (nichtgenomischer und genomischer Mechanismus) in ruhenden und stimulierten humanen PBMC. Dabei zeigten Beclometason und Clobetasol in sehr niedrigen Konzentrationen (10-10, 10-8 M) einen stärkeren Effekt auf den Sauerstoffverbrauch, waren aber in hohen Konzentrationen (10-5, 10-4 M) weniger potent im Vergleich zu Dexamethason. Auch hinsichtlich ihrer genomischen Potenz waren die topischen GC in einer Konzentration von 10-10 M und 10-8 M effektiver als Dexamethason, in höheren Konzentrationen unterschieden sie sich aber nicht. Alle drei GC induzierten Apoptose konzentrationsabhängig und unterschieden sich nicht in Konzentrationen zwischen 10-8 M und 10-5 M. In einer Konzentration von 10-4 M war die Induktion von Apoptose durch die topischen GC in PBMC und Jurkat-T-Zellen aber signifikant stärker im Vergleich zu Dexamethason. Diese Ergebnisse zeigen, dass sich topische und systemische GC in ihrer genomischen und nichtgenomischen Potenz signifikant unterscheiden. Es ist daher davon auszugehen, dass nichtgenomische Effekte eine deutlichere klinische Relevanz besitzen als bisher angenommen. / Several different genomic and non-genomic mechanisms mediate the important anti-inflammatory and immunomodulatory effects of glucocorticoids (GCs). The genomic effects are the most important while the clinical relevance of non-genomic actions is still a matter of debate. We therefore investigated whether beclomethasone and clobetasol are particularly suitable for topical application because they differ in their spectrum of activity from systemically administered GCs such as dexamethasone. We compared effects on oxygen consumption as measured with a Clark electrode (nonspecific non-genomic glucocorticoid effects), on interleukin-6 synthesis by means of ELISA (genomic effects) and on apoptosis using flow cytometry (non-genomic and genomic effects) in quiescent and mitogen-stimulated PBMCs. Beclomethasone and clobetasol had stronger effects on the oxygen consumption of quiescent and stimulated cells at lower concentrations (10-10, 10-8 M) but were less potent at higher concentrations (10-5, 10-4 M) in comparison with dexamethasone. Also in terms of genomic potency, topical GCs were more effective than dexamethasone at 10-10 M and 10-8 M but gave similar results at higher concentrations. The ability of all three GCs to induce apoptosis was found to be concentration-dependent and similar at concentrations between 10-8 and 10-5 M but, compared with 10-4 M dexamethasone, 10-4 M beclomethasone or clobetasol was significantly more effective at inducing apoptosis in both PBMCs and Jurkat T cells. These results show that systemic and topical GCs differ significantly in their ability to induce genomic and non-genomic effects. This suggests that non-genomic effects are more therapeutically relevant in certain clinical conditions than currently assumed.

Les protéines GILZ (Glucocorticoid-Induced Leucine Zipper) et TSC-22 (Transforming growth factor-beta Stimulated Clone-22) appartiennent à la famille de protéines TSC-22D (TSC-22 Domain). GILZ a été décrit précédemment comme étant induit au cours de la déprivation en interleukine-2 (IL-2) des lymphocytes de la lignée cellulaire CTLL-2, permettant ainsi de retarder leur apoptose. Le but de notre travail était de déterminer les rôles respectifs de GILZ et TSC-22 au cours de l’apoptose des cellules CTLL-2.Nos résultats ont permis de montrer que TSC-22 augmentait l’apoptose induite par la déprivation en IL-2 des cellules CTLL-2. Nous avons mis en évidence une augmentation de l’activation des caspases ainsi qu’une régulation positive de l’expression de BIM. Nous avons en outre montré que l’expression de GILZ, protéine anti-apoptotique, induite lors de la déprivation en IL-2, était régulée négativement en présence de TSC-22. Enfin, nous avons montré que l’expression de l’ARNm de gilz était régulée négativement par TSC-22, mais que la stabilité de son ARNm n’était pas modifiée.Notre travail a donc permis de montrer que TSC-22 accélère l’entrée en apoptose des lymphocytes T en régulant négativement l’expression de la protéine anti-apoptotique GILZ. / GILZ (Glucocorticoid-Induced Leucine Zipper) and TSC-22 (Transforming growth factor-beta Stimulated Clone-22) belong to the TSC-22D (TSC-22 Domain) family of proteins. GILZ has been previously shown to be induced upon interleukin-2 (IL-2) deprivation in the T-cell line CTLL-2, allowing cells to delay apoptosis. The aim of our study was to elucidate the respective roles of GILZ and TSC-22 during IL-2 deprivation-induced T-lymphocytes apoptosis.Our results demonstrated that TSC-22 increased CTLL-2 cells apoptosis induced upon IL-2 deprivation. We highlighted in TSC-22 expressing cells both an increase in caspases activation and BIM expression up-regulation. We also demonstrated that GILZ expression, an anti-apoptotic protein, known to be induced after IL-2 withdrawal, was down-regulated in the presence of TSC-22. Moreover, we showed that gilz mRNA expression was also significantly repressed, but gilz mRNA half-life was not modified.Altogether, these results suggest that, in T-cells, TSC-22 could behave as a repressor of GILZ expression, accelerating IL-2 deprivation-induced apoptosis.

Les neutrophiles sont généralement considérés résistants aux glucocorticoïdes. Cependant, peu d’études comparant l’effet de ces drogues sur les neutrophiles et les autres leucocytes sanguins (monocytes, lymphocytes et éosinophiles) ont été rapportées. Dans notre étude, nous avons évalué la réponse aux glucocorticoïdes de ces deux populations cellulaires chez le cheval et l’homme. Les cellules, préalablement isolées du sang de 6 chevaux et 4 sujets humains sains, ont été incubées pendant 5 h en présence de lipopolysaccharide (LPS; 100 ng/mL) seul ou combiné avec de l’hydrocortisone, de la prednisolone ou de la dexaméthasone (10-8M et 10-6M). L’expression d’ARNm pour l’IL-1β, le TNF-α, l’IL-8, la glutamine synthétase et le récepteur α des glucocorticoïdes (GR-α) a été quantifiée par qPCR. Les neutrophiles équins ont également été incubés pendant 20 h en présence de ces 3 glucocorticoïdes et la survie cellulaire a été évaluée par cytométrie de flux et microscopie optique. Nous avons démontré que les glucocorticoïdes inhibaient l’expression des gènes pro-inflammatoires induite par le LPS pour les deux populations cellulaires chez les deux espèces étudiées. L’expression de la glutamine synthétase était également significativement augmentée par les glucocorticoïdes chez les neutrophiles et les autres leucocytes sanguins équins. De manière générale, l’intensité de la réponse aux glucocorticoïdes s’est avérée similaire dans les 2 populations leucocytaires et chez les deux espèces. Les glucocorticoïdes augmentaient également la survie des neutrophiles équins, phénomène également rapporté dans d’autres espèces. Ainsi, les glucococorticoïdes exercent des effets d’intensité comparable sur les neutrophiles et les autres leucocytes sanguins. Nous spéculons que la faible réponse à la corticothérapie observée lors de maladies inflammatoires chroniques neutrophiliques comme l’asthme sévère ou la Maladie Pulmonaire Obstructive Chronique (MPOC) ne s’explique pas par une corticorésistance intrinsèque des neutrophiles. / Neutrophils are generally considered resistant to glucocorticoids compared to other inflammatory cells. However, there are few studies comparing the effects of glucocorticoids in neutrophils and those of other blood leukocytes (monocytes, lymphocytes and eosinophils). In our study, we assessed glucocorticoid-responsiveness in equine and human peripheral blood neutrophils and in neutrophil-depleted leukocytes. Cells were isolated from 6 healthy horses and 4 human healthy subjects. They were incubated for 5 h with or without lipopolysaccharide (LPS; 100 ng/mL) alone or combined with hydrocortisone, prednisolone or dexamethasone (10-8M and 10-6M). IL-1β, TNF-α, IL-8, glutamine synthetase and Glucocorticoid Receptor α (GR-α) mRNA expression was quantified by qPCR. Equine neutrophils were also incubated for 20 h with or without the three glucocorticoids and cell survival was assessed by flow cytometry and light microscopy. We found that glucocorticoids down-regulated LPS-induced pro-inflammatory mRNA expression in both cell populations and species. These drugs also significantly increased glutamine synthetase gene expression in both equine cell populations. The magnitude of glucocorticoid response was generally similar in both cell populations and species. As reported in other species, glucocorticoids significantly increase the survival in equine neutrophils. Based on these results, it appears that glucocorticoids exert effects of similar magnitude on neutrophils and on other blood leukocytes. We speculate that the poor response to glucocorticoids observed in some chronic neutrophilic human diseases such as severe asthma or Chronic Obstructive Pulmonary Disease (COPD) is not explained by an inherent attenuated response of neutrophils to these drugs.

This thesis examines the influence of stress on the activity of hippocampal CA1 area. The main task was to determine whether the stress load affects the changes of the local metabolism of glucocorticoids, and whether the levels of corticosteroid receptors in the CA1 hippocampus are modulated in response to stress. In order to answer these questions, the experiments were carried out using three different rat strains - Fisher, Lewis and Wistar which differ in their activities of hypothalamic-pituitary-adrenal axis. Our results demonstrate that stress has no effect on expression of MR mRNA. Conversely, stress reduces the levels of GR mRNA in CA1 area of the dorsal hippocampus. Moreover, we confirmed that the Lewis and Wistar rats didn't change metabolism of glucocorticoids after stress response. By the Fisher rats increased levels of 11β-HSD1 mRNA expression and therefore increased the metabolism of corticosterone.

Topische Glukokortikoide (GCs) sind wirksam bei Therapie von entzündlichen Hauterkrankungen. Durch ihr Nebenwirkungspotential (z.B. Induktion von Hautatrophie) ist ihr Einsatz jedoch begrenzt. Für die Medikamentenentwicklung ist die Bestimmung des atrophogenen Potenzials neuer Verbindungen daher von großer Bedeutung. Derzeit stehen dafür keine prädiktiven in vitro Modelle zur Verfügung. Ziel dieser Arbeit war daher die Etablierung solcher Modelle. Es wurden kutane Zelltypen (3T3-Zellen, Rattenfibroblasten, HaCaT-Zellen, humane Keratinozyten [NHEK] und Fibroblasten) und Vollhautmodelle (CellSystems AST-2000 und Phenions FTSM) untersucht. Atrophie-Marker, die Proliferation, Kollagen-Metabolismus und Epidermisdicke betreffend, wurden auf mRNA-, Protein- bzw. zellulärer Ebene gemessen. Außerdem wurden mittels Genexpressionsanalysen von GC-behandelter Nagerhaut neue potenzielle Marker identifiziert, deren Regulation in vitro jedoch nicht bestätigt werden konnte. Nach Pilotexperimenten wurden 3 Modelle ausgewählt und für Evaluierungsexperimente mit Referenz-GCs behandelt: 1). MMP1, -2, -3 und -9 mRNA-Expression in NHEK, 2). COL1A1 und COL3A1 mRNA-Expression in 3T3-Zellen, 3.) Epidermisdicke, Kollagen- und MMP-Synthese in FTSM. Die Messparameter der 3 Modelle erwiesen sich als dosisabhängig reguliert und korrelierten mit dem atrophogenen Potenzial der GCs. Schließlich wurde die Prädiktabilität der 3 in vitro Modelle für die in vivo Situation im Nager analysiert. In allen 3 in vitro Systemen induzierte die Behandlung mit einem selektiven GC-Rezeptor-Agonisten weniger atrophogene Effekte als das Referenz-GC. Ähnliche Ergebnisse wurden auch in vivo im Rattenhautatrophie-Modell gefunden. Zusammenfassend wird eine Kaskade von 3 in vitro Modellen empfohlen, um das atrophogene Potential von GC-Rezeptor-Liganden zu bestimmen. Der tatsächliche prädiktive Wert für die klinische Situation sollte in weiteren Studien untersucht werden. / Topical glucocorticoids (GCs) are effective for the therapy of inflammatory skin diseases. However, their use is limited by their side effect potential, with skin atrophy being the most prominent one. Thus, determining the atrophogenic potential of novel compounds is of importance for drug development. Currently, there are no according predictive in vitro models available. The aim of this study was to establish such atrophy models. Rodent and human cutaneous cell types (3T3 cells, rat fibroblasts, HaCaT cells, human keratinocytes [NHEK] and fibroblasts) and human full-thickness skin equivalents (CellSystems AST-2000 and Phenions FTSM) were investigated. Atrophy markers related to proliferation, collagen metabolism and epidermal thickness were measured on mRNA, protein and cellular level, respectively. Additionally, by gene expression profiling of GC-treated rodent skin novel potential markers were identified, but subsequently not confirmed in vitro. After pilot studies 3 models were selected and treated with reference GCs for evaluation experiments: 1.) MMP1, -2, -3 and -9 mRNA expression in NHEK, 2.) COL1A1 and COL3A1 mRNA expression in 3T3 cells, 3.) epidermal thickness, collagen and MMP synthesis in FTSM. The read out parameters of all 3 test systems turned out to be regulated dose-dependently and correlated with the atrophogenic potential of the GCs. Finally, the predictability of the 3 recommended in vitro test system for the rodent in vivo situation was analyzed. In all 3 in vitro test systems, the treatment with a novel selective GC receptor agonist induced less atrophogenic effects than the reference GC clobetasol. Indeed, similar results were found in the hr/hr rat skin atrophy model. In summary, a cascade of 3 in vitro models is recommended to be applied for the characterization of the atrophogenicity of GC receptor ligands. Further experiments are necessary to eventually demonstrate the true predictability of these models for the clinical situation.

O objetivo deste trabalho foi estudar o processo pelo qual hormônios e fatores de crescimento controlam a proliferação celular em mamíferos. O modelo experimental utilizado foi linhagens de células estabelecidas em cultura. Os estudos centraram-se em dois tipos básicos de células: fibroblastos e células adrenais e o ataque experimental foi feito sob dois pontos de vista: bioquímico e genético. O ataque bioquímico envolveu desenvolver estudos cinéticos da síntese de DNA não só durante o carenciamento de células para soro, como também durante a reestimulação de células carenciadas por:soro, hormônios e fatores de crescimento. Medidas do conteúdo intracelular de cAMP foram efetuadas com o intuito de adquirir informações à respeito do mecanismo de ação destes fatores. Um modelo de ciclo celular foi proposto no qual o controle do crescimento seria exercido através de reguladores positivos e negativos que agiriam estimulando ou inibindo a passagem de células do estado de repouso (Go) para a fase proliferativa. Entre os reguladores positivos (estimuladores) do sistema fibroblasto, encontra-se hormônios clássicos, como esteróides e insulina, e fatores de crescimento de natureza hormonal como EGF, PF (fator proteico extraído de glândulas pituitárias) e prostaglandina F2&#945;. O esteróide hidrocortisona pode agir como regulador negativo, inibindo o crescimento de fibroblastos. Medidas do período de tempo transcorrido desde a estimulação de células carenciadas (Go), até o aparecimento da onda de síntese de DNA (período definido operacionalmente como Gl) foram feitas. Em fibroblastos 3T3 este período foi de 12 a 13 horas tanto para células estimuladas com soro como com hormônios clássicos (hidrocortisona, insulina) ou fatores de crescimento (EGF, PF) ou ainda com combinações deles (EGF + PF + insulina; PF + hidrocortisona; PF + hidrocortisona + insulina). No sistema células adrenais, adrenocorticotropina (ACTH) foi o único hormônio clássico que apresentou atividade sobre o crescimento destas células e também o único efetuador negativo encontrado. Neste sistema PF mostrou-se como o único fator com atividade estimulatória sobre o crescimento. Gl aqui foi de 11 horas tanto para células estimuladas com soro como com PF. Além disso os hormônios clássicos hidrocortisona e insulina não apresentaram atividade estimulatória por si só ou em combinação com PF. A análise da ação de hidrocortisona no sistema fibroblasto e de ACTH no sistema células adrenais estimuladas, forneceu evidências de que após deixar Go, em direção a S, numa certa altura de Gl as células tornam-se irreversivelmente comprometidas com o processo replicativo. Este comprometimento parece ocorrer 5 horas antes de S, sendo referido como Glc. Em face destes resultados foi proposto que os reguladores agem estimulando ou inibindo a transição Go &#8594; Glc. Na tentativa de obter maior definição do sistema de controle do crescimento, aproveitamo-nos das vantagens oferecidas pelo modelo experimental usado, para a busca de mutantes do tipo regulatório. Esta busca resultou no isolamento das linhagens ST1 e AR-1, derivadas, respectivamente, de fibroblastos 3T3 e células adrenais Y-l. Entre os vários aspectos interessantes da linhagem ST1 destaca-se: a) o dramático efeito de hidrocortisona causando mudança nas características das células as quais passam de um fenótipo tipicamente transformado para normal. Este fenômeno foi observado tanto \"in vitro\" (através de medidas de parâmetros de crescimento) como \"in vivo\" (através de ensaios de tumorogenicidade); b) as alterações morfológicas de caráter antagônico provocadas, por um lado, pela adição de hidrocortisona (causando achatamento) e, por outro, pela retirada do soro ou adição de cAMP ao meio de cultura (arredondamento). Através do estudo da ação de inibidores, obteve-se evidências do envolvimento de microtúbulos nestas alterações morfológicas. A análise do conteúdo intracelular de cAMP indicou que este nucleotídeo não atua como mediador da ação de hidrocortisona. Sua ação parece ser devida à indução de alterações no sistema superfície celular - membrana -citoesqueleto. Ao contrário de outros variantes de células Y-l resistentes à ACTH, células AR-1 mostraram-se também resistentes a cAMP. A utilidade destas células nos estudos da postulada mediação deste nucleotídeo na ação de ACTH, é óbvia. / The aim of this work was to study the process by which hormones and growth factors control proliferation of mammalian cells. Cell lines established in culture were used as the experimental model. The studies were centered on two basic types of cells: fibroblasts and adrenal cells and the experimental approach was made from two viewpoints: biochemical and genetic. The biochemical approach involved kinetic studies of the DNA synthesis process not only during serum starvation but also during restimulation of serum starved cells by serum, hormones and growth factors. Intracellular cyclic AMP determinations were made in order to gain informations on the mechanism of action of these factors. A cell cycle model was proposed in which cell growth control would be exerted by positive and negative regulators that would act by stimulating or inhibiting the flow of cells from a resting state (Go) to the proliferative phase. Among the positive regulators (stimulators) found for the fibroblast system are: classical hormones, like steroids and insulin, and growth factors of homonal nature, like EGF, PF (protein factor extracted from pituitary glands) and prostaglandin F2&#945;. The steroid hydrocortisone can also act as a negative regulator, inhibiting fibroblast growth. Measurements of the time interval between stimulation of serum starved (Go) cells and the onset of DNA synthesis (period that is operationally defined as Gl) were made. In 3T3 fibroblasts this period was 12 to 13 hours for cells stimulated not only by serum but also by classical hormones (hydrocortisone, insulin) or growth factors (EGF, PF) or even by combinations of these factors (EGF + PF + insulin; PF + hydrocortisone; PF + hydrocortisone + insulin). In the adrenal system, adrenocorticotropin (ACTH) was the only classical hormone to present activity on the growth of these cells and also the only negative regulator found. In this system PF was shown to be the only factor with growth stimulatory activity. GL was estimated as 11 hours for cells stimulated with serum or PF. Moreover hydrocortisone and insulin had no stimulatory activity \"per si\" or in combination with PF. The analysis of hydrocortisone action on the fibroblast system on one hand and of that of ACTH on the adrenal system, on the other, indicated that upon leaving Go, towards S, at a certain point in Gl, cells become irreversibly committed to the replicative process. This commitment seems to occur 5 hours before S and is referred to as Glc. In view of these data we proposed that regulators act by stimulating or inhibiting the transition Go &#8594; Glc. In an attempt to obtain a better definition of the growth control system and taking advantage of the experimental model utilized, we searched for mutants of the regulatory type. This search resulted in the isolation of the lines ST1 and AR-l from 3T3 fibroblasts and Y-l adrenal cells, respectively. Among several interesting aspects of the STl cell line, we point out: a) the dramatic effect of hydrocortisone changing the characteristics of these cells from a typically transformed phenotype to a normal pattern. This phenomenon was observed both \"in vitro\" (by measuring a number of growth parameters) and \"in vivo\" (by tumorogenicity assays). b) morphological alterations of antagonistic nature caused by hydrocortisone (flattening) on one hand, and by the removal of serum or cAMP addition to the culture medium (rounding) on the other. Evidence for the involvement of microtubules in these alterations were obtained through studies on the action of several inhibitors. Quantitative analysis of intracellular cAMP indicated that this nucleotide does not act as a mediator of hydrocortisone action. Rather, this action seems to be due to the induction of alterations on the cell surface-membrane-cytoskeleton system. Contrary to other variants of the Y-1 line which are resistant to ACTH, AR-1 cells are also resistant to cAMP. The usefulness of these cells in studies of the postulated mediation by cAMP of the ACTH action, is obvious.

La NAFLD (non alcoholic fatty liver disease) ou stéatopathie dysmétabolique est la manifestation hépatique du syndrome métabolique. Elle regroupe l’ensemble des lésions hépatiques liées à l’obésité en dehors de toute consommation d’alcool : la stéatose, la NASH (non alcoholic steatohepatitis), la fibrose, la cirrhose et le carcinome hépatocellulaire. Les systèmes immunitaires inné et adaptatif participent activement à la pathologie. J’ai étudié deux axes : l’axe du récepteur des glucocorticoïdes-GILZ dans les cellules de Kupffer et CXCR4-CXCL12 dans les lymphocytes T CD4+.Les cellules de Kupffer (CK) jouent un rôle clé dans la pathologie de la NASH. GILZ (glucocorticoid induced leucine zipper) est exprimé par les monocytes/macrophages et est sous le contrôle du récepteur aux glucocorticoïdes (GR). De plus, GILZ intervient dans l’inhibition des processus inflammatoires. J’ai montré que l’obésité entraîne une diminution de l’expression du GR et de GILZ dans les CK. En utilisant du RU486, un antagoniste spécifique du GR, j’ai prouvé que la diminution de l’expression du GR entraîne la diminution de l’expression de GILZ et sensibilise les CK au LPS. Ce mécanisme joue un rôle déterminant dans le développement de l’inflammation hépatique au cours de l’obésité, en modulant la réponse inflammatoire des CK. Le recrutement de cellules inflammatoires dans le foie est un élément clé de la progression de la NASH. Les lymphocytes T CD4+ issus de souris obèses ont des propriétés chimiotactiques accrues dépendantes de CXCR4. J’ai montré que la NASH augmente les propriétés migratoires dépendantes de CXCR4 des lymphocytes T CD4+ chez l’homme et la souris dans trois modèles murins de NASH. Le traitement de souris obèses par de l’AMD3100, un antagoniste de CXCR4, permet de diminuer le recrutement hépatique de lymphocytes. L’augmentation du chimiotactisme des lymphocytes T CD4+ n’était pas dû, ni à une augmentation de l’expression de CXCR4 et CXCR7, ni même de CXCL12 au niveau du foie. J’ai montré que ce mécanisme dépendait de l’augmentation de l’affinité de CXCR4 pour CXCL12.Ainsi, j’ai mis en évidence deux axes participant à l’inflammation hépatique au cours de l’obésité. Ces axes représentent de nouvelles cibles thérapeutiques potentielles. / NAFLD (non alcoholic fatty liver disease) is the hepatic manifestation of metabolic syndrome. It encompasses the entire spectrum of obesity-related liver lesions : steatosis, NASH (non alcoholic steatohepatitis), fibrosis, cirrhosis and hepatocellular carcinoma. Innate and adaptative immune systems participate actively to the pathophysiology.I studied two axis : the glucocorticoid receptor-GILZ axis in Kupffer cells and CXCR4-CXCL12 in CD4+ T lymphocytes.Kupffer cells (KC) play a key role in pathophysiology of NASH. GILZ (glucocorticoid induced leucine zipper) is expressed by monocytes/macrophages and is under the control of glucocorticoid receptor (GR). Moreover, GILZ takes part in inhibition of inflammatory processes. I showed that obesity induces a decreased expression of GR and GILZ in KC. Using RU486, a GR antagonist, I proved that decreased expression of GR induces the decreased expression of GILZ and sensitize KC to LPS. This mechanism plays a decisive role in initiation of liver inflammation in obesity, modulating inflammatory response of KC. In obese mice, recruitment of inflammatory cells into the liver is a key element in the progression of NASH. CD4+ T lymphocytes from obese mice have enhanced CXCR4-dependent chemotactic properties. I showed that NASH enhances CXCR4-dependent chemotactic properties of CD4+ T lymphocytes in patients and in three mouse models of NASH. Obese mice treatment with AMD3100, a CXCR4 antagonist, decreases lymphocytes recruitement into the liver. Enhanced chemotactic properties of CD4+ T lymphocytes were not due to increased expressions of nor CXCR4 and CXCR7, neither CXCL12 in the liver. I showed that this mechanism was dependent of an increased affinity of CXCR4 to CXCL12.Therefore, I highlighted two axis participating to obesity-related liver inflammation. These axis represent new potential therapeutic targets.

Hormônios glicocorticóides (GCs), através do receptor de glicocorticóide (GR), bloqueiam o processo de inflamação, suprimem a ativação do sistema imune e atuam como agentes inibidores do crescimento, in vitro e in vivo. GR interage com outros fatores de transcrição, como AP-1 e NF-&#954;B. Para estudar o mecanismo de ação de GCs, utilizamos o modelo celular ST1, variante da linhagem C6 de glioma de rato, que é hiper-sensível a GCs. O tratamento hormonal induz completa reversão fenotípica tumoral-normal, bem como inibição dos níveis basal e induzido por TNF-&#945; da atividade de ligação a DNA do fator de transcrição NF-&#954;B. O papel de NF-&#954;B na reversão fenotípica de células ST1, induzida por GCs, foi analisado por: (1) bloqueio da expressão da subunidade RelA de NF-&#954;B através de construções \"antisense\"; (2) inibição da atividade NF-&#954;B com o anti-oxidante curcumina. Após transfecção estável, foram isolados 12 clones transfectados com o vetor pOPI3-RelA(as), expressando o mRNA de RelA na orientação reversa, e 9 clones transfectados com o vetor parental pOPI3CAT. A proliferação destes clones foi analisada através de curvas de crescimento e eficiência de plaqueamento em suspensão de agarose. Não foi possível correlacionar a expressão de RelA com a proliferação celular, pois tanto os clones ST1-RelA(as) como alguns clones ST1-pOPI3CAT apresentaram menor taxa de crescimento e eficiência de plaqueamento em agarose, quando comparados com a célula parental ST1. Curcumina foi capaz de inibir a proliferação e a atividade de ligação a DNA do fator de transcrição NF-&#954;B, indicando que este fator é importante no controle da proliferação das células ST1. A atividade de AP-1 também é modulada negativamente por GC, sugerindo que a inibição da proliferação mediada por GC em células ST1 se dá através da inibição conjunta de NF-&#954;B e AP-1. / Glucocorticoid hormones (GC) bind to their receptor (GR), which acts as a transcription factor in the nucleus, blocking the inflammation process, suppressing activation of the immune system and acting as a growth-repressor and as anti-tumor agent both in vivo and in vitro. GR interacts with other transcription factors, such as AP-1 and NF-&#954;B. To study the mecanism of action of GC, we have been using the ST1 cell model, a variant of the C6 glioma cell line, which is hyper-responsive to GC. Hormonal treatment leads ST1 cells to a dramatic tumoral-normal phenotypic reversion. We previously showed that GCs are able to repress both the basal and the TNF-&#945;-induced levels of NF-&#954;B DNA binding activity in ST1 cells. The role of NF-&#954;B in the tumoral-normal phenotypic reversion induced by GC in ST1 cells was analysed by: (1) blocking the RelA subunit of NF-&#954;B by expression of an antisense construct; (2) inhibition of NF-&#954;B activity by treatment with curcumin (antioxidant). Upon stable transfection, we isolated 12 clones transfected with pOPI3-RelA(as) vector, which express reverse RelA mRNA, and 9 clones transfected with the empty pOPI3CAT vector. Cell proliferation of isolated clones was evaluated by growth curves and soft-agar assays. It was not possible to correlate RelA expression with cell proliferation since both types of clones (transfected with the pOPI3-RelA vector or with the empty vector) displayed a lower growth rate in monolayer culture, and decreased capacity to form colonies in semi-solid substrate, when compared to the non-transfected parental ST1 cell line. Curcumin was able to inhibit ST1 cell proliferation, as well NF-&#954;B DNA-binding, indicating the importance of NF-&#954;B in ST1 cells\' growth control. AP-1 activity is also downregulated by GC, suggesting that GC-mediated inhibition of cell proliferation in ST1 cells is results from concomitant inhibition of NF-&#954;B and AP-1.

Introdução: A deficiência da 21-hidroxilase (21-OHD) é um frequente erro herdado do metabolismo que resulta no comprometimento da síntese do cortisol e/ou aldosterona e aumento da produção de andrógenos. A doença é caracterizada por uma diversidade fenotípica, variando desde virilização pré-natal da genitália externa de fetos femininos e pós-natal em ambos os sexos, com ou sem perda de sal, até quadros assintomáticos. Em seu tratamento é necessária reposição com glicocorticoide para se evitar a insuficiência adrenocortical e os sinais de virilização. Um fino ajuste na dose diária do glicocorticoide é essencial para se evitar sub ou supertratamento, com o objetivo de preservar o potencial de estatura final e fertilidade. Entretanto, tem sido observada maior frequência de obesidade e outras comorbidades metabólicas nestes pacientes; porém, a prevalência destas complicações ainda não é conhecida, bem como se estariam associadas à exposição ao glicocorticoide e/ou com fatores genéticos. Objetivos: avaliar a frequência de obesidade e de síndrome metabólica (SM) em pacientes com 21OHD; caracterizar a distribuição alélica dos polimorfismos dos genes do receptor de glicocorticoide (NR3C1) e da enzima 11beta-hidroxiesteróide desidrogenase tipo I (HSD11B1), e correlacionar a distribuição destes polimorfismos com a presença das complicações metabólicas. Métodos: Foram selecionados 109 pacientes (60 PS/49 VS), sendo 41 crianças e adolescentes (idade média 11,4 ± 3,9 anos) e 68 adultos (idade média 28,4 ± 9 anos) em tratamento com glicocorticoide e com adequado controle hormonal. Pacientes com a forma PS também receberam fludrocortisona. Adequado controle foi caracterizado por concentração normal de atividade plasmática de renina e de andrógenos de acordo com o sexo e idade nos últimos 2 anos. A obesidade nos adultos foi definida pelo IMC >= 30 kg/m² e em crianças e adolescentes pelo IMC acima do percentil 95. Síndrome metabólica foi definida segundo o critério do National Cholesterol Education Program em adultos e crianças. História familiar de hipertensão arterial, diabetes, dislipidemia, obesidade e/ou doença cardiovascular também foi avaliada. Foram mensuradas glicemia, lipoproteínas, triglicérides, colesterol total e insulina. Os alelos BclI, A3669G, ER22/23EK e N363S do gene NR3C1 e o alelo 4436InsA do gene HSD11B1 foram genotipados e as análises de associação com os fenótipos foram realizadas por meio dos testes Chi-quadrado, t-studant e análise de regressão. As análises de correlação foram feitas utilizando o teste de correlação de Pearson. Resultados: Obesidade foi observada em 31,7% das crianças e 23,5% dos adultos. Síndrome metabólica foi observada em 14,6% das crianças e 7,3% dos adultos. A prevalência dos componentes da SM foi maior no grupo dos obesos quando comparada a de pacientes não obesos (crianças e adultos). Não houve correlação significante entre o IMC, sexo, forma clínica da 21-OHD, duração da terapia e dose de GC. História familiar positiva para obesidade, hipertensão, dislipidemia e doença cardiovascular foi mais frequente nos pacientes obesos quando comparada a de pacientes não obesos, em adultos e crianças. Os polimorfismos BclI, A3669G e 4436InsA foram identificados em 23,2%, 9,7% e 14,6% dos alelos das crianças, respectivamente, e nos adultos em 26,4%, 9,6% e 18,4% dos alelos, respectivamente. A variante A3669G foi associada à maiores concentrações de LDL-c em crianças quando comparada aos carreadores do alelo selvagem. Os pacientes adultos carreadores do polimorfismo BclI apresentaram maior IMC, circunferência abdominal e PAS quando comparados aos carreadores do alelo selvagem. Não observamos diferenças estatisticamente significantes no perfil metabólico entre pacientes carreadores e não carreadores do polimorfismo 4436InsA (adultos e crianças). Conclusão: observamos que pacientes 21-OHD possuem maior prevalência de obesidade, e o grupo pediátrico maior prevalência de SM em relação à população de referência, sendo ambas independentes da dose de glicocorticoide e do tempo do tratamento. A presença de perfil metabólico adverso esteve associada à obesidade e à predisposição genética, tais como história familiar e variantes genéticas do receptor de glicocorticoide / Introduction: Congenital adrenal hyperplasia due to 21-hydroxylase deficiency (21OHD) is a common autosomal recessive disorder that leads to decreased glucocorticoid secretion, with or without mineralocorticoid deficiency, and increased androgen production. The disease is characterized by phenotypic variability, including a severe form with prenatal virilization of the external genitalia in female fetuses and postnatal virilization in both sexes, with or without salt loss. Current therapy aims to provide adequate glucocorticoid (GC) replacement and to suppress the abnormal androgen secretion; mineralocorticoid replacement aims to control the renal salt balance to avoid adrenal crisis. Nevertheless, these therapeutic goals are difficult to achieve in practice due to the complexity of replicating the physiologic cortisol circadian rhythm. Increased prevalence of obesity, insulin resistance, hypertension and adverse lipid profile have been observed among CAH patients under GC therapy; however, the extent of its prevalence and also whether it is associated with the GC dose or with genetic factors are not known. Objectives: to evaluate the obesity and metabolic syndrome (SM) frequencies in 21-OHD patients; to characterize the allelic distribution of the NR3C1 and HSD11B1 polymorphisms, and to correlate with the metabolic profile. Methods: One hundred and nine patients (60SW/49SV) were selected, 41 being children and adolescents (mean age 11.4 ± 3.9 yrs) and 68 adults (mean age 28.4 ± 9 yrs) all of whom received GC treatment and had adequate hormonal control. SW patients also received fludrocortisone. Adequate hormonal control was characterized by normal plasmatic rennin activity and androgen levels according to age and sex for at least two years. Blood fasting was used to obtain glucose, lipoproteins, triglycerides, total cholesterol and insulin levels. Obesity in the adult group was defined by BMI >= 30 kg/m², and in the young group by BMI > 95th percentile. Metabolic syndrome was defined by the NCEP ATPIII criteria. Family history of the hypertension, diabetes, dyslipidemia, obesity and/or cardiovascular disease was also evaluated. The BclI, A3669G, ER22/23EK and N363S alleles of the NR3C1 gene and 4436InsA of the HSD11B1 gene were genotyped and association analyses with phenotype were carried out with Chi-square, t-test and regression analysis. Correlation analyses were performed by Pearson correlation test. Results: obesity was observed in 31.7% of children and 23.5% of adults. SM was observed in 14.6% of young and 7.3% of adult patients. SM prevalence was higher in the obese group than the nonobese group (children and adults). There was no significant correlation between GC dose and BMI, sex, clinical form or treatment duration. Prevalence of family history of obesity, hypertension, dyslipidemia and cardiovascular disease was higher in the obese than in non-obese patients (children and adults). The BclI, A3669G and 4436InsA polymorphisms were found in 23.2%, 9.7% and 14.6% of the alleles in children, respectively and in 26.4%, 9.6% and 18.4% of the alleles in adults. The A3669G variant was associated to increased LDL-c levels in comparison with noncarriers in the young group. The BclI adult carriers presented higher BMI, abdominal circumference and systolic blood pressure in comparison with noncarriers. Statistically significant differences were not observed in the metabolic profile between carriers and non-carriers of the 4436InsA polymorphism (children and adults). Conclusion: in the present study, which analyzed the clinical and metabolic profile of 21-OHD patients, high obesity prevalence, independent of GC dose and treatment duration, was observed. Adverse metabolic profile was mainly associated with obesity and genetic predisposition, such as family history and NR3C1 polymorphisms