La spleen tyrosine kinase (Syk) est une protéine kinase cytoplasmique qui intervient dans la signalisation immunitaire. Notre équipe a montré pour la première fois que Syk est exprimée aussi dans les cellules épithéliales mammaires et que son expression est perdue au cours de l’acquisition d’un phénotype invasif/métastatique. Syk agit comme un suppresseur de tumeurs et de métastases dans des modèles de xénogreffes de cancer du sein. Ces observations ont été étayées par des études cliniques qui montrent que la perte d’expression de Syk correspond à un risque accru de développement de métastases (facteur de mauvais pronostic) dans le cancer du sein et d’autres carcinomes. Par une approche de phospho-protéomique quantitative (SILAC), nous avons pu identifier de nouveaux substrats potentiels de Syk dans les cellules de cancer du sein. De façon intéressante, ressortent de nombreuses protéines impliquées dans l'adhésion intercellulaire (E-cadhérine/caténines) et la polarisation épithéliale (eg ZO3, occludine, claudine-3). Ces protéines, qui se localisent aux jonctions d'adhésion et d'occlusion, sont connues comme composants plate-formes de signalisation et exercent souvent une fonction de suppresseur de tumeur.Dans ce travail de thèse je me suis focalisé principalement sur :(i) le rôle de l’activité kinase de Syk dans la régulation du complexe E-cadhérine/caténines et(ii) les conséquences de l’invalidation conditionnelle de Syk dans la glande mammaire murine (développement mammaire et tumorigenèse).Par une approche de phosphorylation in vitro, nous avons montré que la E-cadhérine et différentes caténines sont des substrats directs de Syk. Les résidus tyrosines phosphorylés dans ces protéines ont été identifiés par spectrométrie de masse et les anticorps phospho-spécifiques correspondants ont été générés. En immunofluorescence, Syk endogène colocalise avec la E-Cadhérine au niveau des jonctions adhérentes et la surexpression de Syk stimule la phosphorylation de la E cadhérine et différentes caténines au niveau des jonctions intercellulaires. Des expériences d’immunoprécipitation montrent que les protéines E-cadhérine et caténines phosphorylées restent associées dans un complexe au niveau des jonctions adhérentes. L’extinction de Syk par shRNA dans une lignée de cancer de sein inhibe partiellement la ré-agrégation intercellulaire (2D/3D) et augmente l’invasion et la migration cellulaires et la croissance en 3D dans le Matrigel. Inversement, la surexpression de Syk inhibe la migration et l’invasion et favorise l'adhérence intercellulaire. Syk semble par la phosphorylation du complexe E-cadhérine/caténines consolider leurs interactions renforçant ainsi les jonctions intercellulaires et l’intégrité de l’épithélium, ce qui pourrait révéler un mécanisme majeur responsable de son activité anti-invasive. Leurs mécanismes moléculaires ont été explorés.Ces modèles cellulaires in vitro ont ensuite été étendus vers un modèle intégré murin. L'invalidation homozygote du gène SYK étant létale, nous avons développé un modèle d’invalidation conditionnelle de Syk dans la glande mammaire (Syk-flox:WAP-Cre). Ce modèle nous a permis tout d’abord d’étudier le rôle de Syk dans le développement et la physiologie de la glande mammaire au cours de la lactation et de l’involution, les glandes Syk-négatives montrant des défauts de développement. Il permet à plus long terme également d’évaluer l'implication de Syk dans la formation et la progression du cancer du sein chez des souris cKO Syk, après croisement ou non avec des souris transgéniques exprimant l’oncogène MMTV-Neu/Her2.Déterminer si Syk est un bona fide suppresseur de tumeurs est crucial car un inhibiteur de Syk est en cours d’étude clinique pour le traitement de l’arthrite rhumatoïde. L’identification des voies de signalisation gouvernées par Syk pourrait ultérieurement déboucher sur le développement de nouvelles thérapies ciblant ces protéines et bloquant l'évolution cancéreuse. / The spleen tyrosine kinase (Syk) is a cytoplasmic protein kinase involved in immune-response signaling. Our team showed for the first time that Syk is also expressed in mammary epithelial cells and that its expression is lost during acquisition of an invasive/metastatic phenotype. Syk acts as a tumor and metastasis suppressor in breast cancer xenograft models. Clinical studies corroborated that loss of Syk expression is correlated with a decreased survival and an increased risk of metastasis development (poor prognosis) in breast cancer and other carcinomas. Using a quantitative phospho-proteomic SILAC approach in breast cancer cells, our group identified new potential Syk substrates. Interestingly, many proteins are involved in intercellular adhesion (E-cadherin/catenin) and epithelial polarization (eg ZO3, occludin, claudin-3). These proteins are localized at the adherens and tight junctions and are known as signaling platforms and components often presenting a tumor suppressor function.In this thesis I mainly focused on:(i) the role of the Syk kinase activity in the regulation of the E-cadherin/catenin complex and(ii) the consequences of the conditional Syk knockout in the mouse mammary gland on breast development and tumorigenesis.Using in vitro kinase assays, we demonstrated that E-cadherin (E-Cdh) and different catenins are direct Syk substrates. The phosphorylated tyrosine residues were identified by mass spectrometry and corresponding phospho-specific antibodies were generated. By immunofluorescence, we observed that endogenous Syk and E-Cdh colocalize at adherens junctions (AJ) and that Syk overexpression stimulates Syk-dependent phosphorylation of E-cadherin and different catenins at AJ. Immunoprecipitation experiments indicate phosphorylated E-cadherin and catenin proteins are associated in a complex. Using functional tests, Syk knockdown by shRNA in breast cancer cells partially inhibited intercellular re-aggregation (2D/3D) and increased cell invasion, migration and 3D-growth in Matrigel. Conversely, Syk overexpression inhibited migration and invasion and promoted intercellular adhesion. Thus, Syk seems to strengthen the intercellular junctions and the integrity of the epithelium via the phosphorylation of the E-cadherin/catenin complex of which its molecular mechanisms were explored. This could be a major mechanism responsible for its anti-invasive activity.These in vitro observations were subsequently extended to an integrated mouse model. As the homozygous SYK gene knockout is lethal; we developed a conditional Syk deletion model in the murine mammary gland (Syk-flox:WAP-Cre).This model allowed us to study the role of Syk in the development and physiology of the mammary gland during lactation and involution, the Syk-negative glands showing developmental defects. On a long-term basis, it also allows to assess the involvement of Syk in the formation and progression of breast cancer in aging cKO Syk mice, bred or not with transgenic mice expressing the MMTV-Neu / Her2 oncogene.Whether Syk is a bona fide tumor suppressor is a crucial issue as Syk inhibitors are being evaluated in clinical studies for the treatment of rheumatoid arthritis. Identification of the signaling pathways governed by Syk could lead to the development of new therapies targeting these proteins and blocking tumor development and progression.

The content of the thesis is a description of intracellular processes responsible for cell cycle regulation and reactions of cells to external and internal stimuli. Thoroughly described are important signaling pathways with appropriate methods, which can be used to simulate them in silico. From these cellular processes, a cell cycle model is created and implemented in a tool programmed in C ++ with OpenGL used for visualization. The model is then tested for various cell processes including HeLa cells growth. Finally, the results are compared with the behavior of living cells.

<p>UVOD: Gojaznost je hronično, multifaktorijalno i kompleksno oboljenje povezano sa povećanim rizikom od aterosklerotskih kardiovaskularnih bolesti (KVB). Disfunkcija vaskularnog endotela predstavlja rani događaj u patofiziolo&scaron;kom kontinuumu aterosklerotskog procesa, a produženo izlaganje vaskularnog endotela faktorima rizika za aterosklerozu udruženim sa gojaznosti (insulinska rezistencija, dislipidemija, proinflamatorno/protrombozno stanje), može doprineti procesima aktivacije/disfunkcije endotela i progresiji ateroskleroze u supkliničku, odnosno kliničku formu bolesti. CILJ: Uporediti koncentracije solubilne forme adhezionih molekula &ndash; intracelularnog adhezivnog molekula &ndash;1 (sICAM&ndash;1) i E selektina (sE&ndash;selektin), između ispitanika sa hiperalimentacionim tipom gojaznosti i normalno uhranjenih zdravih ispitanika, kao i utvrditi eventualno postojanje razlika u koncentraciji sICAM&ndash;1 i sE&ndash;selektina između ispitanika kod kojih je merenjem debljine kompleksa intima medija karotidne arterije (IMK) uočen supklinički stadijum ateroskleroze i ispitanika koji imaju normalnu debljinu IMK. Ispitati povezanost parametara telesne kompozicije (ukupne masne mase tela i masne mase abdominalnih depoa), cirkuli&scaron;ućih koncentracija biomarkera disfunkcije vaskularnog endotela (sICAM&ndash;1 i sE&ndash;selektina) i IMK kod ispitanika sa hiperalimentacionim tipom gojaznosti. MATERIJAL I METODE: U istraživanje je uključeno 60 ispitanika sa hiperalimentacionim tipom gojaznosti bez pridruženih komorbiditeta i 30 zdravih normalno uhranjenih učesnika usklađenih sa ispitanicima po godinama života i polu koji su činili kontrolnu grupu. Svim ispitanicima su urađena antropometrijska merenja, analiza komponenata telesne kompozicije (bioelektrična impedansna analiza, Tanita Body Composition Analyzer BC &ndash; 418 MA III), laboratorijska analiza uzoraka krvi na automatizovanim analizatorskim sistemima sa određivanjem parametara metabolizma glukoze (bazalno i 2 h u toku oralnog glukoza tolerans testa), lipida i lipoproteina, inflamacije i homocisteina. Određivanje serumske koncentracije sICAM&ndash;1 i sE&ndash;selektina je vr&scaron;eno ELISA tehnikom (R&amp;D Systems, Inc. Minneapolis, USA). Vrednosti IMK&ndash;a su određivane pomoću karotidnog dupleks ultrazvuka (Aloka SSD&ndash;650 US system, Tokyo), a na osnovu izmerenih (IMK) i normalno očekivanih vrednosti IMK za svakog ispitanika je izračunavan IMK Z&ndash;skor. Supklinički stadijum ateroskleroze je definisan kao vrednost IMK Z&ndash;skora veća od 1 (&scaron;to odgovara vrednosti IMK većoj od 95 percentila normalno očekivane vrednosti u odnosu na pol i godine života ispitanika). REZULTATI: Ispitanici sa hiperalimentacionim tipom gojaznosti su imali statistički značajno vi&scaron;e vrednosti medijane serumske koncentracije sE&ndash;selektina u poređenju sa medijanom serumske koncetracije sE&ndash;selektina učesnika u kontrolnoj grupi (36,2 (33,21&ndash;43.7) vs. 25,14 (23,1&ndash;29,48) ng/mL, P=0,00). Gojazni ispitanici III stepena gojaznosti su imali statistički značajno vi&scaron;u medijanu serumske koncenracije sE&ndash;selektina u odnosu na medijanu sE&ndash;selektina u ispitanika I stepena gojaznosti (41,5 (36,58&ndash;49,48) vs. 34,34 (22,49&ndash;36,62) ng/mL, P=0,00), odnosno medijanu sE&ndash;selektina u ispitanika II stepena gojaznosti (41,5 (36,58&ndash;49,48) vs. 32,1 (26,1&ndash;43,64) ng/mL, P=0,00). Nije uočena statistički značajna razlika u medijani serumske koncentracije sE&ndash;selektina između ispitanika I i II stepena gojaznosti (34,34 (22,49&ndash;36,62) vs. 32,1 (26,1&ndash;43,64) ng/mL, P=0,12). Gojazni ispitanici su imali statistički značajno vi&scaron;e vrednosti medijane serumske koncentracije sICAM&ndash;1 u poređenju sa medijanom serumske koncetracije sICAM&ndash;1 učesnika u kontrolnoj grupi (266,8 (245,8&ndash;326,73) vs.183,32 (167,9&ndash;208,57), P=0,00). U ispitivanoj grupi gojaznih uočena je statistički značajna razlika u medijani koncentracije sICAM&ndash;1 između ispitanika u I, II i III stepena gojaznosti (200,6 (190,26 - 264,4) vs. 278,5 (219,54 - 343,24) vs. 329,6 (259,2 - 350,34) ng/mL, P=0,00). Učestalost IMK Z&ndash;skor &gt; 1 je bila statistički značajno eća u gojaznih ispitanika u odnosu na kontrolnu grupu (36/60 vs. 7/30, P=0,00). Ispitanici sa IMK Z&ndash;skor &gt; 1 su imali statistički značajno vi&scaron;u medijanu koncentracije sICAM&ndash;1 u odnosu na ispitanike kod kojih je IMK Z&ndash;skor &le; 1 (295,4 (238,46&ndash;340,38) vs. 244,2 (227,35&ndash;260,38), P=0.00). Regresionom analizom (R2=0,71, korigovani R2=0,59) je utvrđeno da su parametri hsCRP (&beta;=0,45, P=0,00), HOMA&ndash;IR (&beta;=0,44, P=0,035) i ISI (&beta;=&ndash;0,36, P=0,028) nezavisno i statistički značajno povezani sa serumskom koncentracijom sE&ndash;selektina. Regresionom analizom (R2=0,65, korigovani R2=0,56) je utvrđeno da parametri ITM (&beta;=0,55, P=0,00), trigliceridi (&beta;=0,30, P=0,00), HDL holesterol (&beta;=&ndash;0,31, P=0,00), odnos TG/HDL&ndash;holesterol (&beta;=0,33, P=0,01), hsCRP (&beta;=0,31, P=0,00) i fibrinogen (&beta;=0,34, P=0,00) su nezavisno i statistički značajno povezani sa serumskom koncentracijom sICAM&ndash;1. U faktorskoj analizi je izdvojeno pet faktora &ldquo;gojaznost&rdquo;, &ldquo;insulinska rezistencija&rdquo;, &ldquo;aterogeni faktor&rdquo;, &ldquo;endotelna disfunkcija i vaskularna inflamacija&rdquo; i &ldquo;metabolički faktor&rdquo; koji obja&scaron;njavaju 69.72% ukupne varijanse ispitivanog uzorka. U multivarijabilnom modelu sa svim faktorima zajedno kojim je obja&scaron;njeno ukupno 75% varijanse, jedino je faktor gojaznost imao statički značajan i nezavistan uticaj na vrednost IMK Z&ndash;skor &gt; 1 (OR=2,74 (CI 1,18&ndash;6,33), P=0,019). U faktoru gojaznost su se izdvojili parametri: FAT trunk (%), FAT (%), OS (cm), ITM (kg/m2), LDL &ndash; holesterol (mmol/L), SP (mmHg), HOMA1&ndash;%B, fibrinogen (g/L), ApoB/apoA-I i hsCRP (mg/L). Univarijantom logističkom regresijom je uočeno da porast u koncentraciji LDL&ndash;H (OR=5,33 (CI 1,9&ndash;14,2), P=0,02) i koncentraciji hsCRP&ndash;a (OR=2,53 (CI 1,3&ndash;3,98),P=0,017) povećava rizik za postojanje vrednosti IMK Z&ndash;skor &gt; 1. ZAKLJUČAK: Cirkuli&scaron;uće serumske koncentracije biomarkera disfunkcije vaskularnog endotela, sE&ndash;selektina i sICAM&ndash;1, su značajno vi&scaron;e kod ispitanika sa hiperalimentacionim tipom gojaznosti u odnosu na njihove koncentracije u normalno uhranjenih ispitanika. U gojaznih ispitanika, koncentracija sE&ndash;selektina je povezana sa vrednostima indeksa insulinske rezistencije i biomarkera inflamacije, dok je koncentracija sICAM&ndash;1 značajno povezana sa udelom masne mase u ukupnoj telesnoj masi, vrednostima biomarkera inflamacije i proaterogenih lipidskih parametara. Ispitanici kod kojih postoji uvećanje abdominalnih masnih depoa i ukupnog udela masnog tkiva u telesnoj masi, vrednosti SKP, koncentracije LDL &ndash; holesterola, vrednosti lipoproteinskog indeksa ApoAI/apoB, bazalne insulinemije i biomarkera inflamacije, imaju trostruko povećan rizik od supkliničkog stadijuma ateroskleroze. U gojaznih osoba prilikom procene rizika od aterosklerotskih KVB, potrebno je utvrditi fenotipske osobine vaskularnog endotela i eventualno postojanje supkliničkog stadijuma ateroskleroze, da bi se definisale adekvatne preventivne mere i sagledale potencijalne terapijske mogućnosti.</p> / <p>INTRODUCTION: Obesity is a chronic, multifactorial and complex disease associated with an increased risk of atherosclerotic cardiovascular diseases (CVD). Vascular endothelial dysfunction is an early event in the pathophysiological continuum of atherosclerotic process. The prolonged exposure of vascular endothelium to classical and obesity associated risk factors (insulin resistance, dyslipidemia, proinflammatory state) could further promote deterioration of endothelial function and progression of atherosclerosis to subclinical or clinical form of disease. OBJECTIVE: The aim of the study was to compare the concentration of soluble forms of adhesion molecules, intracellular adhesion molecule-1 (sICAM-1) and E-selectin (sE-selectin), between obese subjects and normal weight healthy subjects, as well as to determine the possible existence of differences in concentration of sICAM-1 and sE-selectin among subjects with subclinical stage of atherosclerosis (assessed by measuring the thickness of the intima media complex of the carotid artery (IMT)), and subjects who have a normal value of IMT. Also, the aim was to determine the association between the parameters of body composition (total body fat mass and fat mass intra-abdominal depots), circulating concentrations of sICAM-1 and sE-selectin, and value of IMT in obese subjects. MATERIALS AND METHODS: The study included 60 obese nondiabetic subjects, without preexisting CVD and other associated comorbidity, and 30 healthy normal weight age and sex matched participants. All subjects underwent anthropometric measurements, analysis of the components of body composition (bioelectrical impedance analysis, Tanita Body Composition Analyzer BC - 418 MA III), laboratory analysis of blood samples (automated analyzer systems) with determining the parameters of glucose metabolism (basal and 2 h during the oral glucose tolerance test), lipids and lipoproteins, inflammation and homocysteine. Serum concentrations of sICAM-1 and sE-selectin were determined by ELISA (R &amp; D Systems, Inc., Minneapolis, USA). The values of IMK were determined by carotid duplex ultrasound (Aloka &ndash; ProSound ALPHA 10). IMK Z-score was calculated using the measured and the normal expected values of IMT for each patient. Subclinical stage of atherosclerosis was defined as the value of IMT Z-score greater than 1 (corresponding to the 95th sex-age-specific percentile of IMT measurements). RESULTS: Obese subjects had significantly higher median sE-selectin serum concentrations compared to median serum concentrations of sE-selectin in the normal weight subjects (36.2 (33.21-43.7) vs 25.14 (23.1-29.48) ng/mL, P=0.00). Morbid obesity subjects had significantly higher sE-selectin median serum concentration compared to the median sE-selectin concentration in moderate obese subjects (41.5 (36.58-49.48) vs 34.34 (22.49-36.62) ng/mL, P=0.00), and compared to the median sE-selectin concentration in severely obese subjects (41.5 (36.58-49.48) vs. 32.1 (26.1-4364) ng / mL, P=0.00). Obese subjects had significantly higher median sICAM-1 serum concentration compared to median sICAM-1 serum concentration in the control group (266.8 (245.8-326.73) vs. 183.32 (167.9-208.57), P=0.00). In the obese group, we observed a statistically significant difference in median sICAM-1 serum concentrations between moderate, severely and morbid obese subjects (200.6 (190.26-264.4) vs. 278.5 (219.54-343.24) vs. 329.6 (259.2-350.34) ng/mL, P=0.00). The frequency of IMT Z-score&gt; 1 was significantly higher in the obese group compared to control group (36/60 vs. 7/30, P=0.00). Subjects with IMT Z-score&gt; 1 had significantly higher median concentrations of sICAM-1 compared to those in which the IMK Z-score &le; 1 (295.4 (238.46-340.38) vs. 244.2 ( 227.35-260.38), P=0.00). In regression analysis (R2=0.71, adjusted R2=0.59), hsCRP (&beta;=0.45, P=0.00), HOMA-IR (&beta;=0.44, P=0.035) and ISI (&beta;=-0.36, P=0.028) were independently and significantly associated with serum sE-selectin concentration. In regression analysis (R2=0.65, adjusted R2=0.56), BMI (&beta;=0.55, P=0.00), triglycerides (&beta;=0.30, P=0.00), HDL cholesterol (&beta;=-0.31, P=0.00), the ratio of TG/HDL-cholesterol ratio (&beta;=0.33, P=0.01), hsCRP (&beta;=0.31, P=0.00 ) and fibrinogen (&beta;=0.34, P=0.00) were independently and significantly associated with serum sICAM-1 concentration. In the Factor analysis, five factors &quot;obesity&quot;, &quot;insulin resistance&quot;, &quot;atherogenic factor,&quot; &quot;endothelial dysfunction and vascular inflammation&quot; and &quot;metabolic factor&quot; explained 69.72% of the total variance of the test sample. In a multivariate model with all the factors together (75% of the total variance), &quot;obesity&quot; factor was significantly and independently associated with IMT Z-score&gt; 1 (OR=2.74 (CI 1.18-6.33), P=0.019). The &quot;obesity&quot; factor consisted of parameters: trunk fat (%), fat (%), waist (cm), BMI (kg/m2), LDL &ndash; cholesterol (mmol/L), systolic blood presure (mmHg), HOMA1-% B, fibrinogen (g/L), Apo B/apoA-I and hsCRP (mg/L). Logistic regression analysis showed that independent predictors of IMT Z-score&gt; 1 were LDL-cholesterol (OR=5.33(CI 1.9-14.2), P=0.02) and hsCRP (OR=2.53 (CI 1.3-3.98), P=0.017). CONCLUSION: Circulating serum concentrations of endothelial dysfunction biomarkers, sE-selectin and sICAM-1, were significantly higher in obese subjects compared to concentration in the normal weight subjects. In obese subjects, the concentration of sE-selectin was associated with insulin resistance and biomarkers of inflammation, whereas sICAM-1 concentration was associated with fat mass, inflammation biomarkers and the proatherogenic lipid parametars. In individuals with increased abdominal fat depots and total proportion of fat mass in the body weight, values of SBP, LDL-C, ApoB/apoA-I, basal insulin levels and biomarkers of inflammation, there is threefold increased risk of subclinical stages of atherosclerosis. In order to define an adequate preventive measures and possible therapeutic options for atherosclerotic CVD in obese subjects, it is necessary to assess the phenotypic characteristics of vascular endothelium and possible presence of subclinical stage of atherosclerosis.</p>

Zirkadiane Uhren sind Zell-autonome Oszillatoren. Aus diesem Grund ist deren interzelluläre Kopplung essentiell, um die Synchronität zirkadianer Oszillatornetzwerke zu erhalten und die Störung zirkadianer Gewebsfunktionen zu verhindern. Neuronale Oszillatoren des Nucleus suprachiasmaticus (SCN), der Schrittmacher-Uhr im Zentralnervensystem der Säugetiere, koppeln interzellulär und über den Austausch sekretierter Neurotransmitter. Die Fähigkeit zirkadianen Oszillatoren peripherer Gewebe interzellulär zu koppeln ist hingegen stark umstritten und molekulare Mechanismen sind unbekannt. In dieser Dissertation zeigen wir, dass periphere Oszillatoren in der Tat interzellulär über den Austausch sekretierter Signalmoleküle koppeln und identifizieren TGF-b als peripheren Kopplungsfaktor. Weiterhin zeigen wir, dass TGF-b die cAMP Enhancer-Motiv abhängige, als auch Immediate Early Expression des Uhr-Gens PER2 induziert und folglich die Phasenanpassung molekularer zirkadianer Oszillationen reguliert. Genetische und pharmakologische Störeinflüsse verursachen die Dysregulation des TGF-b Signalweges und begünstigen die Desynchronisierung zellulärer Oszillatoren, welche sich in Amplitudenreduktion und verstärkter Sensitivität gegenüber Zeitgeber-Signalen äußert. Die in dieser Dissertation präsentierten Ergebnisse, legen einen bisher unbekannten molekularen Mechanismus intrazellulärer Kopplung peripherer zirkadianer Oszillatoren dar und eröffnen neue Perspektiven auf die Bedeutung der Synchronität peripher zirkadianer Uhren für rhythmische Organfunktionen und zirkadiane Gesundheit. / Circadian clocks are cell-autonomous oscillators. Intercellular coupling is crucial to prevent desynchronization of oscillator networks and thus, the disruption of circadian tissue functions. While neuronal oscillators within the mammalian central clock, the suprachiasmatic nucleus (SCN), couple intercellularly via the exchange of secreted neurotransmitters, intercellular coupling among peripheral oscillators is highly debated and molecular mechanisms are unknown. Here, we show that peripheral circadian oscillators couple intercellularly via exchange of secreted signaling molecules and identify TGF-ß as peripheral coupling factor. TGF-ß signaling induces the cAMP response element dependent, immediate-early expression of the clock gene PER2, thereby phase-adjusting the molecular circadian oscillator. Genetic or pharmacologic disruption of TGF-ß signaling causes desynchronization of cellular oscillators resulting in amplitude reduction and increased sensitivity towards Zeitgeber cues. Our findings reveal a previously unknown mechanism of peripheral coupling and open new perspectives on the importance of peripheral clock synchrony for rhythmic organ functions and circadian health.

Yes / Alterations of Endothelial cells (ECs) play a critical role in different pathogenesis of many serious human diseases, and dysfunction of the vascular endothelium is an indicator for human disorders. Endothelial dysfunction is considered to be an early indicator for atherosclerosis, which is characterised by overexpression of adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Hydrogen peroxide (H2O2) released via neutrophils is an important mediator of endothelial cell function. Ambient production of superoxide anion (O2−) and subsequently H2O2 at low levels is critical for regulating endothelial cell functions and proliferation. In this study, we investigated the effects of H2O2 on the expression of adhesion molecules VCAM-1 and ICAM-1 in cultured human umbilical vein endothelial cells (HUVECs). Intracellular superoxide anion production was detected by using p-Nitro Blue Tetrazolium (NBT) assay. Our results showed that administration of 100μM of H2O2 on HUVECs for 2, 6, 12 and 24 h induced a time-dependent increase in ICAM-1 and VCAM-1 mRNA and protein expression levels with a significant increase observed from 6 h. HUVECs exposed to H2O2 exhibit increased O2−, suggesting that H2O2 induced oxidative stress may be a reasonable for atherosclerosis. This increase can be reduced by the flavonoid, N-acetyl cysteine (NAC). The modulation of endothelial cell function through this mechanism may underlie the contribution of H2O2 to the development of vascular disease.

Les phospholipases A2 sécrétées (sPLA2) font partie d’une grande famille d’enzymes impliquées dans la synthèse d’écosanoïdes, de chimiokines et dans l’expression de molécules d’adhérence. Ce groupe comprend dix isoformes différentes (sPLA2-IB, -IIA, -IIC, -IID, -IIE, -IIF, -III, -V, -X et XII) dont la majorité sont surexprimées en présence de molécules pro-inflammatoires telles que l’interleukine-1β (IL-1 β) et le lipopolysaccharide bactérien (LPS). La sPLA2-IIA fut longtemps considérée comme la principale sPLA2 associée à l’inflammation. Toutefois, un nombre grandissant d’études suggère l’implication d’autres isoformes dans la réponse inflammatoire. Étant donné la similarité structurelle des différentes isoformes de sPLA2, la majorité des inhibiteurs présentement disponibles sont non spécifiques et bloquent simultanément plus d’une sPLA2. De ce fait, encore peu de choses sont connues quant au rôle précis de chacune des sPLA2 dans la réponse inflammatoire. Ayant accès à des souris génétiquement modifiées n’exprimant pas la sPLA2-V (sPLA2-V-/-), nous avons donc investigué le rôle spécifique de la sPLA2-V dans le recrutement leucocytaire induit par le LPS, ainsi que sa capacité à moduler l’expression de certaines molécules d’adhérence. Pour ce faire, nous avons utilisé le modèle inflammatoire de la poche d’air sous-cutanée. L’administration de LPS dans la poche d’air de souris contrôles (WT) entraîne un recrutement leucocytaire important. Cet appel de cellules inflammatoires est cependant significativement diminué chez les souris sPLA2-V-/-. De plus, l’expression des molécules d’adhérence VCAM-1 et ICAM-1 est également diminuée chez les souris sPLA2-V-/- comparativement aux souris WT. Nos résultats démontrent donc le rôle important de la sPLA2-V dans le recrutement leucocytaire et l’expression de molécules d’adhérence induits par le LPS, confirmant ainsi l’implication de cette enzyme dans le processus inflammatoire. / Secretory phospholipases A2 (sPLA2s) are well known for their contribution in the biosynthesis of inflammatory eicosanoids. These enzymes also participate in the inflammatory process by regulating chemokine production and protein expression of adhesion molecules. The majority of sPLA2 isoforms are up-regulated by proinflammatory stimuli such as bacterial lipopolysaccharide (LPS), which predominantly increases the expression of group V sPLA2 (sPLA2-V). Furthermore, it has recently been shown that sPLA2-V is a critical messenger in the regulation of cell migration during allergic airway responsiveness. Herein, we investigated the effect of sPLA2-V on LPS-mediated leukocyte recruitment and its capacity to modulate adhesion molecule expression. We conducted our study in the murine air pouch model, using sPLA2-V null mice (sPLA2-V-/-) and control wild-type (WT) littermates. We observed that LPS (1 μg/mL)-mediated leukocyte migration in sPLA2-V-/- was attenuated by 52 and 86% after 6 and 12 hours of treatment, respectively, as compared to WT mice. In WT mice, treatment with the cell-permeable sPLA2 inhibitor (12-epi-scalaradial; SLD) reduced LPS-mediated leukocyte recruitment by 67%, but had no additional inhibitory effect in sPLA2-V-/- mice. Protein analyses from the air pouch skin were carried out upon LPS-challenge, and the expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 were both significantly reduced in sPLA2-V-/- mice as compared to control WT mice. Together, our data demonstrate the role of sPLA2-V in LPS-induced ICAM-1 and VCAM-1 protein overexpression and leukocyte recruitment, supporting the contribution of sPLA2-V in the development of inflammatory innate immune responses.

A vascularização tem um papel central na progressão tumoral e representa um alvo terapêutico de grande interesse. A inibição da angiogênese tem potencial de retardar a progressão tumoral e inibir metástase. Em decorrência disto, terapias anti-angiogênicas têm demonstrado ser promissora no controle do crescimento tumoral. Segundo a literatura, interferon-? (IFN?, ativador do sistema imune inato e adaptativo) e p19Arf (supressor de tumor e parceiro funcional de p53), quando estudados individualmente, alteram a vasculatura tumoral. Nosso grupo construiu e utilizou vetores adenovirais recombinantes portadores dos cDNAs de INFbeta e p19Arf e observou que a transferência desta combinação de genes induziu morte celular e diminuiu progressão tumoral, resultados foram observados em modelos murinos de melanoma B16 de terapia genica in situ, vacina profilática e vacina terapêutica. Neste trabalho, exploramos a ideia que a combinação dos vetores adenovirais portadores de INFbeta e p19Arf proporcionam efeitos anti-angiogênicos através de seu impacto em células endoteliais. Para averiguarmos essa hipótese, células endoteliais murinas (tEnd) foram transduzidas com os vetores adenovirais, revelando que o vetor Ad-p19 confere inibição da proliferação, formação de tubos, migração e induz aumento na expressão de genes relacionados a via de p53 e morte celular. O vetor Ad-IFNbeta sozinho ou adicionado em combinação com Ad-p19, não teve impacto significante nestes ensaios. Alternativamente, a influencia indireta, ou parácrina, nas células tEnd cultivadas juntamente com as células B16 transduzidas com os vetores adenovirais também foi investigada. Quando as células B16 foram transduzidas com Ad-IFNbeta ou a co-transdução Ad-IFNbeta+Ad-p19 em co-cultura com a linhagem tEnd, houve inibição da proliferação. Não observamos efeito inibitório na tEnd da co-cultura quando as células da B16 foram transduzidas somente com Ad-p19. Seguindo o ensaio de co-cultura, produzimos meio condicionado da B16 transduzida com os vetores e aplicamos esses meios nas células tEnd. Observamos que Ad-IFN, sozinho ou em combinação com Ad-19, diminuiu a viabilidade, proliferação e levou a morte das células tEnd. Neste trabalho, constamos que inibição de células endoteliais pode ser realizada por transdução direta com Ad-19 ou quando estas células são expostas ao ambiente modulado por células tumorais transduzidas com o vetor Ad-IFNbeta. Mesmo que a transferência gênica de ambos IFNbeta e p19Arf não demonstrou ser uma abordagem superior à aplicação dos genes isolados, observamos que nossa abordagem pode ter um impacto importante na inibição da angiogênese pelas células endoteliais / The vasculature plays a central role in tumor progression and represents a therapeutic target of great interest. Inhibition of angiogenesis has the potential to slow down tumor progression and inhibit metastasis. As a result, anti-angiogenic therapies have been shown to be promising for the control of tumor growth. According to the literature, interferon ? (IFN?, activator of the innate and adaptive immune systems) and p19Arf (tumor suppressor and functional partner of p53) when studied individually alter tumor vasculature. Our group has constructed and used recombinant adenovirus vectors carrying the cDNAs of INFbeta and p19Arf and noted that the transfer of this combination of genes induced cell death and decreased tumor progression, as observed in the B16 murine model of in situ melanoma gene therapy as well as prophylactic and therapeutic vaccine approaches. In this study, we explore the idea that the combination of adenoviral vectors bearing INFbeta and p19Arf produce anti-angiogenic effects due to their impact on endothelial cells. To test this hypothesis, murine endothelial cells (tEnd) were transduced with adenoviral vectors, revealing that Ad-p19 vector confers inhibition of proliferation, tube formation, migration and induces increased expression of genes related to the p53 cell death pathway. The Ad-IFNbeta vector alone had no significant impact on these tests. Alternatively, influences on paracrine effects are evaluated on endothelial cells co-cultured with B16 cells that were previously transduced with adenoviral vectors. When the B16 cells were transduced with Ad-IFNbeta or co-transduced with Ad-IFNbeta + Ad-p19, co-culture resulted in the inhibition of proliferation of the endothelial cells. When B16 cells were transduced with Ad-p19 only, co-culture did alter endothelial cell behavior. Following the co-culture assay, we produce conditioned medium from B16 cells that were transduced with the vectors and applied the media on tEnd cells. We noted that conditioned medium derived from B16 transduced with Ad-IFN alone or in combination with Ad-19 decreased the viability and proliferation and induced cell death of tEnd. In this work, we show that inhibition of endothelial cells can be performed directly by transduction with Ad-19 or when such cells are exposed to the environment modulated by tumor cells transduced with Ad-IFNbeta. Even though the gene transfer of both IFNbeta and p19 was not found to be superior to the application of single genes, we observed that our approach may have an important impact on the inhibition of angiogenesis through endothelial cells

Introdução: O objetivo foi avaliar a expressão de algumas proteínas no endométrio durante a fase lútea do ciclo menstrual de mulheres férteis e inférteis, por meio imunoistoquímica de micro-arranjos teciduais (TMA). Métodos: Analisou-se a expressão de dez proteínas em 52 amostras de endométrio obtidas nas fases lútea inicial, intermediária (janela de implantação) e final. Resultados: As proteínas, fator inibidor de leucemia (LIF), fator de crescimento insulinóide tipo 1 (IGF-1), receptor de progesterona (PR), claudina-4, receptor de fator de crescimento vascular endotelial 3 (VEGFR-3) e citoqueratina 7 (CK-7) mostraram-se expressas no endométrio nas fases lútea inicial, intermediária e final. A proteína morfogenética óssea 4 (BMP-4) expressou-se no endométrio nas fases lútea inicial e intermediária. As proteínas citoqueratina 17 (CK-17), substância solúvel 100 (S100) e calretinina não se expressaram no endométrio durante os três períodos avaliados. Houve correlação entre as expressões protéicas de LIF, IGF-1 e PR. As proteínas LIF e BMP-4 foram diferencialmente expressos no endométrio nas fases lútea inicial, intermediária e final. As proteínas claudina-4 e PR não se expressam simultâneamente no endométrio durante a fase lútea. Conclusão: Baseados nos resultados deste estudo podemos sugerir que a presença das proteínas LIF, IGF-1 e PR durante a janela implantacional teria relevância como preditor do adequado desenvolvimento do endométrio. / Introduction: The objective of this study was to evaluate endometrial protein expressions from fertile and infertile women during the luteal phase of the menstrual cycle by immunohistochemistry in tissue microarrays (TMA). Method: The expression of ten proteins obtained from 52 endometrial samples in the initial, mid (window of implantation) and late (premenstrual) phases of the menstrual cycle were evaluated. Results: The proteins leukemia inhibitory factor (LIF), insulin like growth factor 1 (IGF-1), progesterone receptor (PR), claudin-4, vascular endothelial growth factor receptor 3 (VEGFR-3), and cytokeratin 7 (CK-7) were expressed in the endometrium in the three intervals of the luteal phase. Endometrial expression of the morphogenetic bone protein 4 (BMP-4) occurred during the initial and mid luteal phases. Cytokeratin 17, substance 100 and calretinin were not expressed in the luteal phase. There were positive correlations among endometrial expressions of LIF, IGF- 1, and PR. LIF and BMP-4 were differently expressed in the initial, mid and late phases of the luteal phase. Claudin-4 and PR did not express simultaneously during the different intervals of the luteal phase. Conclusion: These findings suggest that positively correlated endometrial expressions of LIF, IGF-1 and PR at the window of implantation could characterize an adequately developed and receptive endometrium.

Introdução: O objetivo foi avaliar a expressão de algumas proteínas no endométrio durante a fase lútea do ciclo menstrual de mulheres férteis e inférteis, por meio imunoistoquímica de micro-arranjos teciduais (TMA). Métodos: Analisou-se a expressão de dez proteínas em 52 amostras de endométrio obtidas nas fases lútea inicial, intermediária (janela de implantação) e final. Resultados: As proteínas, fator inibidor de leucemia (LIF), fator de crescimento insulinóide tipo 1 (IGF-1), receptor de progesterona (PR), claudina-4, receptor de fator de crescimento vascular endotelial 3 (VEGFR-3) e citoqueratina 7 (CK-7) mostraram-se expressas no endométrio nas fases lútea inicial, intermediária e final. A proteína morfogenética óssea 4 (BMP-4) expressou-se no endométrio nas fases lútea inicial e intermediária. As proteínas citoqueratina 17 (CK-17), substância solúvel 100 (S100) e calretinina não se expressaram no endométrio durante os três períodos avaliados. Houve correlação entre as expressões protéicas de LIF, IGF-1 e PR. As proteínas LIF e BMP-4 foram diferencialmente expressos no endométrio nas fases lútea inicial, intermediária e final. As proteínas claudina-4 e PR não se expressam simultâneamente no endométrio durante a fase lútea. Conclusão: Baseados nos resultados deste estudo podemos sugerir que a presença das proteínas LIF, IGF-1 e PR durante a janela implantacional teria relevância como preditor do adequado desenvolvimento do endométrio. / Introduction: The objective of this study was to evaluate endometrial protein expressions from fertile and infertile women during the luteal phase of the menstrual cycle by immunohistochemistry in tissue microarrays (TMA). Method: The expression of ten proteins obtained from 52 endometrial samples in the initial, mid (window of implantation) and late (premenstrual) phases of the menstrual cycle were evaluated. Results: The proteins leukemia inhibitory factor (LIF), insulin like growth factor 1 (IGF-1), progesterone receptor (PR), claudin-4, vascular endothelial growth factor receptor 3 (VEGFR-3), and cytokeratin 7 (CK-7) were expressed in the endometrium in the three intervals of the luteal phase. Endometrial expression of the morphogenetic bone protein 4 (BMP-4) occurred during the initial and mid luteal phases. Cytokeratin 17, substance 100 and calretinin were not expressed in the luteal phase. There were positive correlations among endometrial expressions of LIF, IGF- 1, and PR. LIF and BMP-4 were differently expressed in the initial, mid and late phases of the luteal phase. Claudin-4 and PR did not express simultaneously during the different intervals of the luteal phase. Conclusion: These findings suggest that positively correlated endometrial expressions of LIF, IGF-1 and PR at the window of implantation could characterize an adequately developed and receptive endometrium.

Les synucléionopathies représentent un groupe de maladies neuro-dégénératives incurables du système nerveux central. Elles regroupent entre autres la maladie de Parkinson, l’atrophie multi-systématisée et la maladie à corps de Lewy. Toutes ces maladies se caractérisent par un déclin progressif des fonctions motrices, cognitives, comportementales et autonomiques. La mal-conformation et l’agrégation de la protéine α-synuclein qui forme des inclusions intraneuronales sont des éléments communs à toutes les synucleinopathies. Ces inclusions portent le nom de corps de Lewy et se forment dans des neurones ou cellules gliales appartenant à des régions cérébrales spécifiques. Elles sont vraisemblablement à l’origine de la perte progressive de neurones dans certaines parties du cerveau. Dans le cas de la maladie de Parkinson et dans d’autres maladies neuro-dégénératives, il a été démontré que la pathologie se propage anatomiquement d’une manière spécifique et prévisible au niveau cérébrale. Ceci suggère donc que la progression de la maladie est étroitement liée au transfert des agrégats d’α-synucléine. Ce procédé est très similaire à celui impliqué dans la maladie du prion qui elle en revanche est infectieuse. Par ailleurs, des inclusions neuronales d’α-synucléine ont été identifiées dans des neurones dopaminergiques d’origine fœtaux qui avaient été transplanté dans des cerveaux de patients parkinsoniens. Cette étude a permis d’envisager pour la première fois la possibilité de la transmission d’inclusions d’α-synucléine entre les neurones. Bien que de nombreuses études aient démontré la propagation d’α-synucléine in vitro et in vivo, le mécanisme permettant ce transfert n’est pas clairement établi. Par conséquent, ma thèse s’attache à étudier le mécanisme de transfert d’assemblages d’α-synucléine (i.e., oligomères et fibrilles). Dans un premier temps, j’ai apporté la preuve que les assemblages d’α-synucléine transfèrent de manière efficace entre les cellules neuronales via les Tunneling nanotubes (TNT). Les TNT sont définis comme étant des ponts membranaires riches en F-actine et permettant de connecter physiquement le cytoplasme de cellules éloignées. Au niveau subcellulaire, j’ai démontré que les assemblages d’α-synucléine qui transfèrent se trouvent dans des lysosomes. En revanche, après le transfert, ces assemblages se retrouvent libres dans le cytoplasme. J’ai également mis en évidence qu’à la suite du transfert, permis par les TNT, les fibrilles d’α-synucléine sont capables de recruter et d’induire l’agrégation de l’α-synucléine soluble afin de perpétuer le processus d’agrégation à l’infinie. Ces résultats indiquent que les TNT peuvent représenter un moyen efficace permettant le transfert d’assemblages d’α-synucléine. Cette découverte offre de nouvelles opportunités pour le développement de nouveaux agents neuro-protectifs contre la propagation des synucléinopathies. / Synucleinopathies are a group of fatal neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy, characterized by a chronic and progressive decline in motor, cognitive, behavioral, and autonomic functions. The hallmark of these diseases is the misfolding and aggregation of α-synuclein protein accumulating into intracellular inclusions Lewy bodies in neurons and glial cells which leads to the loss of neurons in specific brain regions. In the case of Parkinson’s disease and other neurodegenerative diseases, the pathology was shown to progress throughout the brain in a specific and predictable manner suggesting that the progression of the diseases is linked to the transfer of aggregated α-synuclein that is reminiscent of prion diseases that are infectious. Importantly, upon transplantation of fetal dopaminergic neurons in the brain of Parkinson’s patients, neuronal inclusions were found in the grafted neurons strongly suggesting that α-synuclein inclusions could transmit between neurons. While several studies showed α-synuclein propagation in vitro and in vivo the mechanism of intercellular transfer remains elusive. The aim of my thesis was to study the mechanism of transfer of α-synuclein assemblies (i.e., oligomers and fibrils) involved in Parkinson’s pathogenesis. I evidenced that α-synuclein assemblies transferred efficiently via tunneling nanotubes (TNT), F-actin based membranous bridges connecting the cytoplasm of remote cells. I demonstrated that, at the sub-cellular level, the transferred α-synuclein assemblies were specifically confined in lysosomes and that upon transfer a large amount of α-synuclein was found free in the cytosol of acceptor cells. Finally, I showed that after TNT-mediated transfer α-synuclein fibrils recruited and seeded the aggregation of the soluble α-synuclein protein in order to perpetuate aggregation. The identification of TNT as an efficient means of α-synuclein transfer opens new avenues to the development of novel therapies targeting the spreading into the brain of amyloidogenic proteins involved in neurodegenerative diseases.