Thèse (Ph. D.)--Université Laval, 2005. / Titre de l'écran-titre (visionné le 23 février 2006). Dans le titre et le dépouillement, le symbole + est suscrit. Bibliogr.

Purpose: Traumatic brain injury (TBI) leads to important and deleterious neuroinflammation, as evidenced by edema, cytokine production, induction of nitric oxide synthase, and leukocyte infiltration. Strategies that block inflammatory and oxidative mediators have been shown to induce neuroprotective and anti-inflammatory effects after brain injury. After TBI, cerebral vascular endothelial cells play a crucial role in the pathogenesis of inflammation. In this study, we hypothesized that cerebral vascular endothelial cells play a crucial role in the pathogenesis of inflammation after TBI and, in conjunction with leukocytes, represent a key cellular target for statin therapy. We investigated the effect of acute and continuous treatment of simvastatin on behavior and inflammation in adult rats following experimental TBI. Materials and Methods: Cortical contusions were induced using a device adapted from the impact method. There were 3 groups: (1) sham group, craniotomy only; (2) control group, TBI without treatment; and (3) treatment group, TBI with simvastatin administration. The treatment group received 15 mg/kg of simvastatin daily for 3 days. Neurological function was assessed with the grip test (Grip strength meter, Singa). Results: Non-treatment control group had a significantly greater increase in ICAM-1 expression from pre-injury to the post-injury 72 h time point, compared to the simvastatin treatment group. The treatment group had a significantly smaller amount of reduction in successful trials in grip test than the control group did from baseline to 72 h. The analysis of western blot and pathological study also demonstrated similar results. Conclusion: Our findings indicate that continuous administration of simvastatin after injury attenuates the cerebral vascular endothelial inflammatory response and improves functional and histological outcomes in a rat model of TBI. This improvement is associated with a reduction in expression of ICAM-1 in the blood and brain after rat TBI when compared with the untreated control group. Hence, we recommend simvastatin administration in the first 72 h following TBI.

O presente estudo teve como objetivo avaliar o perfil da molécula relacionada à inflamação (ICAM-1), citocinas e da atividade das NTPDases como potencial influência sobre a genotoxicicdade em trabalhadores expostos ocupacionalmente a HPA. Este estudo incluiu 45 taxistas e 40 indivíduos com atividades administrativas (não-expostos ocupacionalmente), ambos nãi fumantes. O monitoramento biológico foi realizado pela quantificação do 1-hidroxipireno (1-pireno OH) urinário. A expressão de ICAM-1 (CD54) em neutrófilos foi realizada por citometria de fluxo. O perfil de hidrólise das NTPDases em plaquetas foi determinada pelo método colorimétrico. Além disso, os níveis de malondialdeído no plasma (MDA), citoquinas inflamatórias (IL-1β, IL-6, IL-10, TNF-α e IFN-γ) e o dano ao DNA (ensaio cometa e do micronúcleo) foram também avaliados. Os resultados demonstraram que os níveis de 1-OH pireno foram significativamente aumentados nos motoristas de táxi em comparação com o grupo não exposto ocupacionamente (p <0.0001); também foi positivamente correlacionada com neutrófilos ICAM-1, níveis de MDA e biomarcadores de danos no DNA. A expressão de ICAM-1 em neutrófilos foi significativamente elevado em motoristas de táxi (p <0.05), bem como os níveis de MDA (p <0.01), sendo a última positivamente correlacionada com a % de DNA na Cauda e frequência de MN. Aumento da hidrólise de ATP e ADP forma encontrados nos taxistas. Concentrações dos marcadores pró-inflamatórios foram aumentadas e anti-inflamatórias (IL-10) diminuída no grupo exposto. Para o teste de ensaio de micronúcleos e cometa, houve aumento significativo em motoristas de táxi, inclusive depois da adição de enzimas de reparo. Correlações positivas foram encontradas entre IL-1β, IL-6, TNF-α, IFN-γ e preditores de danos no DNA (% de DNA na cauda e frequência de MN), enquanto que a IL-10 está negativamente correlacionada com os biomarcadores de lesão ao DNA. Em resumo, a exposição ocupacional à poluição do ar pode levar a anormalidade homeostática como potencial contribuição para o processo aterosclerótico. Este estudo mostrou também que a exposição crônica à poluição do ar pode causar danos no DNA relacionado com a peroxidação lipídica e processo inflamatório. / The present study aimed to evaluate the profile of inflammatory molecule (ICAM-1), cytokines and the NTPDases activity as potential influence on genotoxicity process in workers exposed occupationally to PAH. This study included 45 taxi drivers and 40 non-occupationally exposed subjects, both non smorkers. Biological monitoring was performed by quantification of urinary 1-hydroxypyrene (1-OH pyrene). The expression of ICAM-1 (CD54) in neutrophil was performed and the hydrolysis profile of the NTPDases in platelets was determined. Plasma malondialdehyde (MDA) levels, inflammatory cytokines and DNA damage (comet and micronucleus assays) were also evaluated. The results demonstrated that the 1-OH pyrene levels were significantly increased in taxi drivers (p<0.0001); were also positively correlated to neutrophil ICAM-1 expression, MDA levels and biomarkers of DNA damage. ICAM-1 expression in neutrophil was significantly elevated in taxi drivers (p<0.05), as well as MDA levels (p<0.01), being the last positively correlated with % Tail DNA and MN frequency. ATP and ADP hydrolysis was increased in taxi drivers. Pro-inflammatory markers concentrations were increased and anti-inflammatory (IL-10) was decreased in exposed group. For the comet assay and micronucleus test, increase was significant in taxi drivers, inclusive after repair enzymes. Positively correlations were found between IL-1β, IL-6, TNF-α, IFN-γ and predictors of DNA damage (%Tail DNA and MN frequency), while IL-10 is negatively correlated with the biomarkers of DNA lesion. In summary, occupational exposure to air pollution, especially to PAHs, may be related with homeostatic abnormality as potential contribute to atherosclerosis process. This study showed also that the chronic exposure to outdoor air pollution may cause DNA damage related with lipid peroxidation and inflammatory process.

abstract: The common cold is a significant cause of morbidity world-wide, with human rhinovirus infections accounting for a majority colds suffered each year. While the symptoms of the common cold are generally mild and self-limiting, vulnerable populations such as individuals with asthma can experience severe secondary complications including acute asthma exacerbation which can result in severe morbidity. Most human rhinovirus types utilize Intercellular Adhesion Molecule-1 (ICAM-1) as a receptor to enter cells and initiate infection. Expression of this cell-surface protein is elevated in the respiratory tract of asthma patients. The theoretical basis for this research is the observation that plasma measures of the soluble form of Intercellular Adhesion Molecule-1 (sICAM-1) decrease in response to vitamin C supplementation. As rhinovirus infection occurs in the upper respiratory tract, the primary aim of this study was to evaluate change in sICAM-1 concentration in nasal lavage of asthmatic individuals in response to vitamin C supplementation. Otherwise healthy asthmatic adults between the ages of 18-65 years who were not currently using steroidal nasal sprays, smoking, or actively training for competitive sports were recruited from a university community and surrounding area to participate in an 18-day double-blind randomized placebo-controlled supplement study with a parallel arm design. 13 subjects were stratified based on age, gender, BMI and baseline plasma vitamin C level to receive either 500 mg vitamin C twice daily (VTC, n=7) or placebo (PLC, n=6). Biochemical measures included nasal lavage sICAM-1, plasma sICAM-1, plasma histamine, and plasma vitamin C. Survey measures included Wisconsin Upper Respiratory Symptom Survey-21 to assess colds, Daytime Symptom Diary Scale to assess asthma symptoms, and measures of diet quality including a vitamin C food frequency questionnaire and Rapid Eating Assessment for Participants. No between group comparison of means reached significance (Mann-Whitney U test, p>0.05). Nasal lavage sICAM-1 levels were decreased in VTC group by 37% at study day 4, although this finding did not reach significance. Findings in this study can be used to develop future investigations into the response of nasal lavage sICAM-1 to vitamin C supplementation. / Dissertation/Thesis / Masters Thesis Nutrition 2014

O presente estudo teve como objetivo avaliar o perfil da molécula relacionada à inflamação (ICAM-1), citocinas e da atividade das NTPDases como potencial influência sobre a genotoxicicdade em trabalhadores expostos ocupacionalmente a HPA. Este estudo incluiu 45 taxistas e 40 indivíduos com atividades administrativas (não-expostos ocupacionalmente), ambos nãi fumantes. O monitoramento biológico foi realizado pela quantificação do 1-hidroxipireno (1-pireno OH) urinário. A expressão de ICAM-1 (CD54) em neutrófilos foi realizada por citometria de fluxo. O perfil de hidrólise das NTPDases em plaquetas foi determinada pelo método colorimétrico. Além disso, os níveis de malondialdeído no plasma (MDA), citoquinas inflamatórias (IL-1β, IL-6, IL-10, TNF-α e IFN-γ) e o dano ao DNA (ensaio cometa e do micronúcleo) foram também avaliados. Os resultados demonstraram que os níveis de 1-OH pireno foram significativamente aumentados nos motoristas de táxi em comparação com o grupo não exposto ocupacionamente (p <0.0001); também foi positivamente correlacionada com neutrófilos ICAM-1, níveis de MDA e biomarcadores de danos no DNA. A expressão de ICAM-1 em neutrófilos foi significativamente elevado em motoristas de táxi (p <0.05), bem como os níveis de MDA (p <0.01), sendo a última positivamente correlacionada com a % de DNA na Cauda e frequência de MN. Aumento da hidrólise de ATP e ADP forma encontrados nos taxistas. Concentrações dos marcadores pró-inflamatórios foram aumentadas e anti-inflamatórias (IL-10) diminuída no grupo exposto. Para o teste de ensaio de micronúcleos e cometa, houve aumento significativo em motoristas de táxi, inclusive depois da adição de enzimas de reparo. Correlações positivas foram encontradas entre IL-1β, IL-6, TNF-α, IFN-γ e preditores de danos no DNA (% de DNA na cauda e frequência de MN), enquanto que a IL-10 está negativamente correlacionada com os biomarcadores de lesão ao DNA. Em resumo, a exposição ocupacional à poluição do ar pode levar a anormalidade homeostática como potencial contribuição para o processo aterosclerótico. Este estudo mostrou também que a exposição crônica à poluição do ar pode causar danos no DNA relacionado com a peroxidação lipídica e processo inflamatório. / The present study aimed to evaluate the profile of inflammatory molecule (ICAM-1), cytokines and the NTPDases activity as potential influence on genotoxicity process in workers exposed occupationally to PAH. This study included 45 taxi drivers and 40 non-occupationally exposed subjects, both non smorkers. Biological monitoring was performed by quantification of urinary 1-hydroxypyrene (1-OH pyrene). The expression of ICAM-1 (CD54) in neutrophil was performed and the hydrolysis profile of the NTPDases in platelets was determined. Plasma malondialdehyde (MDA) levels, inflammatory cytokines and DNA damage (comet and micronucleus assays) were also evaluated. The results demonstrated that the 1-OH pyrene levels were significantly increased in taxi drivers (p<0.0001); were also positively correlated to neutrophil ICAM-1 expression, MDA levels and biomarkers of DNA damage. ICAM-1 expression in neutrophil was significantly elevated in taxi drivers (p<0.05), as well as MDA levels (p<0.01), being the last positively correlated with % Tail DNA and MN frequency. ATP and ADP hydrolysis was increased in taxi drivers. Pro-inflammatory markers concentrations were increased and anti-inflammatory (IL-10) was decreased in exposed group. For the comet assay and micronucleus test, increase was significant in taxi drivers, inclusive after repair enzymes. Positively correlations were found between IL-1β, IL-6, TNF-α, IFN-γ and predictors of DNA damage (%Tail DNA and MN frequency), while IL-10 is negatively correlated with the biomarkers of DNA lesion. In summary, occupational exposure to air pollution, especially to PAHs, may be related with homeostatic abnormality as potential contribute to atherosclerosis process. This study showed also that the chronic exposure to outdoor air pollution may cause DNA damage related with lipid peroxidation and inflammatory process.

Irrespective of plentiful efforts to enhance primary prevention and early detection, the number of melanoma cases in the United States has increased steadily over the past 30 years, thus greatly affecting public health and the economy. We have investigated the effects of five novel aPKC inhibitors; 2-acetyl-1,3-cyclopentanedione (ACPD), 3,4-Diaminonaphthalene-2,7-disulfonic acid (DNDA), [4-(5-amino-4-carbamoylimidazol-1-yl)-2,3-dihydroxycyclopentyl] methyl dihydrogen phosphate (ICA-1T) along with its nucleoside analog 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1S) and 8-hydroxy-1,3,6-naphthalenetrisulfonic acid (ζ-Stat) on cell proliferation, apoptosis, migration and invasion of two malignant melanoma cell lines compared to normal melanocyte cell lines. Molecular docking data suggested that both ACPD and DNDA specifically bind to protein kinase C-zeta (PKC-ζ) and PKC-iota (PKC-ι) while both ICA-1 compounds specifically bind to PKC-ι, and ζ-Stat showed a high affinity towards PKC-ζ. Kinase activity assays were carried out to confirm these observations. Results suggest that PKC-ι is involved in melanoma malignancy than PKC-ζ. Both isoforms promote the activation of nuclear factor (NF)-κB and protein kinase B (AKT) thereby supporting survival and progression. In addition, we demonstrated that PKC-ι induced the metastasis of melanoma cells by activating Vimentin, and PKC-ι inhibition downregulated epithilial-mesencymal transition (EMT), while inducing apoptosis. Of note, PKC-ἱ specific inhibitors downregulated the expression of both PKC-ι and phosphorylated PKC-ι, suggesting that PKC-ι plays a role in regulating its own expression in melanoma. We also report the underlaying mechanisms of the transcriptional regulation of PKC-ι (PRKCI gene) expression in melanoma. c-Jun, interferon-stimulated gene factor 3 (ISGF3), paired box gene 3 (PAX3), early growth response protein 1 (EGR1) and forkhead box protein O1 (FOXO1), which bind on or near the promoter sequence of the PRKCI gene, were analyzed for their role in PKC-ι regulation in SK-MEL-2 and MeWo cell lines. We silenced selected transcription factors using siRNA, and the results revealed that the silencing of c-Jun and FOXO1 significantly altered the expression of PRKCI. The levels of both phosphorylated and total PKC-ι increased upon FOXO1 silencing and decreased upon c-Jun silencing, suggesting that c-Jun acts as an upregulator, while FOXO1 acts as a downregulator of PRKCI expression. We also used a multiplex ELISA to analyze multiple pathways other than NF-κB that were affected by treatment with PKC-ι inhibitor. The silencing of NF-κB p65 and PKC-ι by siRNA suggested that the regulation of PKC-ι expression was strongly associated with FOXO1. In addition, we observed a significant decrease in the mRNA levels of both interleukin (IL)-6 and IL-8, with a significant increase in the levels of IL-17E and intercellular adhesion molecule 1 (ICAM-1) upon the knockdown of expression of PKC-ι in both cell lines. This suggested that PKC-ι expression was affected by these cytokines in an autocrine manner. Overall, the findings of this study suggest that PKC-ι inhibition suppresses its own expression, diminishing oncogenic signaling, while upregulating anti-tumor signaling, thus rendering it an effective novel biomarker for use in the design of novel targeted therapeutics for melanoma.

Hintergrund und Fragestellung: Das NLRP3-Inflammasom ist Teil des angeborenen Immunsystems und spielt eine wichtige Rolle für pro-inflammatorische Prozesse im Rahmen der sterilen Entzündung und der Pathogenese der Atherosklerose. Das NLRP3-Inflammasom wird nicht nur durch molekulare Strukturen von Krankheitserregern, sondern auch durch endogene Gefahrensignale, wie beispielsweise oxidiertes LDL, Cholesterinkristalle, oxidativer Stress oder extrazelluläres ATP, aktiviert. Bei Aktivierung bilden sich hochmolekulare NLRP3-Inflammasomkomplexe, bestehend aus dem NLRP3-Rezeptor, dem Adapterprotein ASC und dem vom Adapterprotein gebundenen Effektorenzym Caspase-1. Im Zuge der Inflammasom-Aktivierung kommt es zur Induktion von Pyroptose, einem programmierten und mit Entzündung assoziierten Zelltod, der mit einer Porenbildung in der Zellmembran einhergeht. Dabei werden pro-inflammatorische Zytokine in ihre bioaktiven Formen gespalten und in den extrazellulären Raum freigesetzt. Neben den Zytokinen können auch ganze Inflammasomkomplexe freigesetzt werden, wodurch diese ebenfalls in die Blutzirkulation gelangen. Die Bedeutung und Wirkung dieser extrazellulären NLRP3-Inflammasome ist noch weitgehend unbekannt. Daher wurde in den beiden wesentlichen Fragestellungen der Arbeit untersucht, ob Endothelzellen extrazelluläre Inflammasomkomplexe internalisieren und dadurch pro-atherogene Effekte ausgelöst werden können und ob zirkulierende Inflammasomkomplexe im menschlichen Blut nachgewiesen werden können. Methoden und Ergebnisse: Extrazelluläre Inflammasomkomplexe konnten aus Zellüberstand von mit Inflammasom-Aktivatoren behandelten humanen Monozyten isoliert werden. Mittels Western-Blot erfolgte der Nachweis des Adapterproteins ASC und des NLRP3-Rezeptors. Durch den NLRP3-Inhibitor MCC950 konnte eine Reduktion der Freisetzung von Inflammasomkomplexen in den Zellüberstand gezeigt werden. Für die Untersuchungen der Wirkung extrazellulärer Inflammasomkomplexe auf Endothelzellen wurde eine Methode zur Isolation von fluoreszenzmarkierten NLRP3-YFP-Inflammasomkomplexen aus einer stabilen NLRP3 (p.D303N)-YFP HEK-Zelllinie etabliert. Histologische Analysen zeigten, dass diese von humanen koronaren Endothelzellen aufgenommen werden können. Die immunhistochemischen Befunde bestätigten sich in der Durchflusszytometrie (Image StreamR). Die Auswertung der immunfluoreszenzmikroskopischen Aufnahmen ergab, dass im Mittel 9 % ± 2,3 % der humanen umbilikalvenösen Endothelzellen und 26 % ± 9,6 % der humanen koronararteriellen Endothelzellen NLRP3-YFP-Inflammasomkomplexe internalisierten. Expressionsanalysen zeigten, dass durch die Behandlung von humanen Endothelzellen mit NLRP3-Inflammasomkomplexen eine signifikant gesteigerte Produktion des Oberflächenadhäsionsmoleküls ICAM1 induziert wird. Im Vergleich zu unbehandelten Zellen waren die mRNA-Expression 2,5-fach und die Proteinlevel 6,9-fach erhöht. Die funktionelle Relevanz wurde durch den Nachweis einer vermehrten Adhäsion von Monozyten deutlich. Mit Calcein gefärbte Monozyten wurden vier Stunden mit koronararteriellen Endothelzellen inkubiert. Die anschließend photometrisch erhobenen Daten zeigten eine um 49,6% verstärkte Adhäsion von Monozyten an die vorher mit extrazellulären Inflammasomkomplexen behandelten Endothelzellen im Vergleich zu unbehandelten Zellen. Die Monozytenadhäsion an das Endothel stellt einen essentiellen Schritt in der Pathogenese der Atherosklerose dar. Diese Zellkultur-Ergebnisse zeigen, dass das extrazelluläre NLRP3-Inflammasom relevanten Einfluss auf das Endothel nehmen kann. Um die klinische Relevanz von extrazellulären NLRP3-Inflammasomen zu eruieren, wurde humanes Serum auf das Adapterprotein ASC hin untersucht. Im Rahmen dieser Dissertationsarbeit wurde die Messung von ASC bei Patienten mit Sepsis als Positivkontrolle im Vergleich zu gesunden Probanden als Negativkontrolle etabliert und validiert. Im Western-Blot konnte gezeigt werden, dass Patienten mit Sepsis mehr ASC-Komplexe aufweisen als gesunde Probanden. Dieser Befund konnte in der quantitativen Auswertung mittels ASC-ELISA bestätigt werden. Es waren signifikant höhere ASC-Konzentrationen in den Serumproben der Patienten mit Sepsis (3,2 ± 0,7 ng/ml) als in gesunden Kontrollen (0,3 ± 0,1 ng/ml) nachweisbar. Diskussion: Diese Ergebnisse zeigen, dass extrazelluläre NLRP3-Inflammasomkomplexe von humanen koronararteriellen Endothelzellen aufgenommen werden und dort pro-atherosklerotische Prozesse induzieren. Die erhobenen Daten weisen damit auf eine neue Domäne der zellulären Signaltransduktion hin, welche für Endothelzellen und im Rahmen der sterilen Entzündung relevant scheint. Die Messung erhöhter ASC-Spiegel im Serum von Sepsis-Patienten lässt ebenfalls eine Assoziation von Inflammasomkomplexen mit im Körper ablaufender systemischer Inflammation annehmen. Auf dem Boden der Befunde müssen weitere Studien beantworten, ob sich die Quantifizierung zirkulierender Inflammasomkomplexe als Biomarker oder zur Risikostratifizierung eignet. Des Weiteren unterstützen die Daten zukünftige Ansätze einer therapeutischen Modulation des intra- und des extrazellulären NLRP3-Inflammasoms.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Le virus de l’immunodéficience humaine de type-1 (VIH-1) a été identifié comme étant l’agent responsable de la pandémie qui frappe actuellement notre civilisation. En une trentaine d’années le virus à causé la mort de plus de 35 millions de personnes. Une telle épidémie dans l’histoire de l’humanité n’est pas une première; rappelons-nous dans le passé, la peste noire ou encore la grippe espagnole qui ont fait elles aussi des millions de morts. Cependant, pour la première fois dans l’ère moderne, nous avons la possibilité de lutter contre ce fléau grâce à l’étude approfondie de la biologie du virus qui a permis, entre autres, l’avènement de la trithérapie. Le VIH-1 acquiert un nombre impressionnant de molécules cellulaires tout au long de son cycle réplicatif. En dépit de tous les efforts consacrés à l’étude des molécules de l’hôte, le(s) mécanisme(s) exact par lequel toutes ces molécules sont acquises n'est toujours pas connu. Néanmoins, dans le cas d'ICAM-1, une des molécules transmembranaires les plus étudié il apparaît que le précurseur viral Pr55Gag est un candidat potentiel d'interaction avec ICAM-1. Par conséquent, nous avons étudié et caractérisé au niveau moléculaire le processus d'incorporation d'ICAM-1 en utilisant dans un premier temps un modèle de pseudo particules virales (VLPs) dérivé de Pr55Gag. La substitution de plusieurs domaines de Pr55Gag tels que la nucléocapside, SP2 et p6 n'ont pas eu d'effet sur son acquisition. Par la suite, nous avons démontré que la protéine de matrice (MA) est nécessaire à son incorporation. Nous avons confirmé ces résultats préliminaires en générant le mutant de matrice dans un clone moléculaire couramment utilisé en laboratoire (NL4.3). Des études complémentaires suggèrent que les deux tiers C-terminal de la MA sont importants et en particulier treize acides aminés présents dans l'hélice-α 5. De plus, en se basant sur la modélisation 3D des interactions protéines-protéines et en validant par la suite ces prédictions par immunocapture, nous avons trouvé qu'une série d'acides aminés acides de la MA interagit avec des acides aminés basiques présents sur le domaine cytoplasmique d'ICAM-1 et sont responsables de son incorporation. En résumé, nos résultats apportent de nouvelles connaissances dans le mécanisme moléculaire régissant l'acquisition d'ICAM-1, une molécule de l'hôte connu pour renforcer l'infectiosité virale et moduler la pathogénèse du VIH-1.

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