Atherosclerosis is thought to be initiated by endothelial cell dysfunction. Research described in this dissertation is focused on interactions of nutrients, cytokines and pharmaceutical compounds in the intracellular signaling pathways leading to endothelial cell activation. The flavonoid quercetin could significantly downregulate the inflammatory pathways induced by linoleic acid as determined by DNA binding assays of the proinflammatory transcription factors nuclear factor-kappaB and activator protein-1 as well as by gene expression studies of interleukin-6 and vascular adhesion molecule-1. Interestingly, quercetin and vitamin E also prevented the linoleic acid-induced activation of PPAR DNA binding - suggesting a role of oxidation in the fatty acid-mediated induction of PPAR. In addition, we studied an interaction of zinc with the antiinflammatory transcription factors, peroxisome proliferator activated receptors (PPARs) alpha and gamma. Our data suggest that PPAR alpha and gamma and their synthetic agonists require zinc for their antiinflammatory properties in endothelial cells. We could confirm the importance of zinc in PPAR gamma signaling in vivo by a decreased PPAR DNA binding activity in livers of zinc deficient mice. Furthermore, zinc had dramatic lipid lowering effects in LDL-receptor deficient mice on a diet rich in corn oil. Triglycerides, phospholipids and cholesterol levels were significantly elevated in mice receiving a zinc deficient diet when compared to control and where decreased in zinc supplemented animals. Zinc deficiency also increased oxidative stress as determined by quantitation of plasma isoprostanes and mRNA expression of glutathione reductase. In conclusion, our data show novel interactions of proinflammatory nutrients, such as linoleic acid, with antioxidant and anti-inflammatory nutrients, such as quercetin and zinc.

Aufgrund seiner potentiell gesundheitsfoerdernden Wirkung wurde das Falvonol Quercetin in den letzten Jahren intensiv untersucht. Daten zur Bioverfuegbarkeit nach oraler Applikation sind jedoch selten und widerspruechlich. Fruehere Untersuchungen deuteten darauf hin, dass die Disposition von Quercetin von der Zuckerkomponente des Glykosids oder der Pflanzenmatrix abhaengen koennte. Um den Einfluss der Zuckerkomponente oder der Matrix auf die Resorption von Quercetin festzustellen, wurden zwei isolierte Quercetinglykoside sowie zwei Pflanzenextrakte in einer vierarmigen, randomisierten cross-over Studie an 12 gesunden Probanden getestet. Jeder Proband erhielt eine Zwiebelzubereitung oder Quercetin-4'-O-glucosid, jeweils entsprechend 100 mg Quercetinaglykon, sowie Quercetin-3-O-rutinosid oder Buchweizenkrauttee entsprechend 200 mg Quercetinaglykon. Die Proben wurden mittels HPLC und Coulometrischer Arraydetektion analysiert. Im Plasma wurden ausschliesslich Quercetinglucuronide detektiert. Freies Quercetin und die Glykoside waren nicht nachweisbar. Die Bioverfuegbarkeit und Pharmakokinetik nach Applikation von Zwiebeln und Quercetin-4'-glucosid zeigte keine signifikanten Unterschiede. Maximale Plasmakonzentrationen von 2.3±1.5 µg·mL-1 and 2.1±1.6 µg·mL-1 (MW±SD) wurden nach 0.7±0.2 h und 0.7±0.3 h erreicht. Nach Einnahme von Buchweizenkraut und Rutin wurden maximale Plasmakonzentrationen (trotz der doppelten Dosis) von nur 0.6±0.7 µg·mL-1 und 0.3±0.3 µg·mL-1 nach 4.3±1.8 h bzw. 7.0±2.9 h erreicht. Die terminale Halbwertszeit lag bei ca. 11 h fuer alle vier Pruefpraeparate. Die Disposition von Quercetin ist daher primaer von der Zuckerkomponente abhaengig. Zu einem geringern Anteil beeinflusst die Pflanzenmatrix im Falle von Buchweizenkrauttee sowohl Geschwindigkeit als auch Ausmass der Resorption. Der Resorptionsort scheint fuer Quercetin-4‘-O-glucoside und Quercetin-3-O-rutinoside unterschiedlich zu sein. Die bedeutung spezifischer carrier fuer die Resorption von Quercetinglykosiden sowie von intestinalen ß-Glucosidasen muss in weiteren Untersuchungen geklaert werden. / Due to its potentially beneficial impact on human health the polyphenol quercetin has come into the focus of medicinal interest. However, data on the bioavailability of quercetin after oral intake are scarce and contradictory. Previous investigations indicate that the disposition of quercetin may depend on the sugar moiety of the glycoside or the plant matrix. In order to determine the influence of the sugar moiety or matrix on the absorption of quercetin, two isolated quercetin glycosides and two plant extracts were administered to 12 healthy volunteers in a four-way cross-over study. Each subject received an onion supplement or quercetin-4‘-O-glucoside both equivalent to 100 mg quercetin, as well as quercetin-3-O-rutinoside and buckwheat tea both equivalent to 200 mg quercetin. Samples were analyzed by HPLC with a 12-channel coulometric array detector. In human plasma only quercetin glucuronides, but no free quercetin, could be detected. There was no significant difference in the bioavailability and pharmacokinetic parameters between the onion supplement and quercetin-4‘-O-glucoside. Peak plasma concentrations were 2.3±1.5 µg·mL-1 and 2.1±1.6 µg·mL-1 (mean±SD) and were reached after 0.7±0.2 h and 0.7±0.3 h, respectively. After administration of buckwheat tea and rutin, however, peak plasma levels were (despite the higher dose) only 0.6±0.7 µg·mL-1 and 0.3±0.3 µg·mL-1, respectively. Peak concentrations were reached 4.3±1.8 h after administration of buckwheat tea and 7.0±2.9 h after ingestion of rutin. The terminal elimination half life was about 11 h for all treatments. Thus, the disposition of quercetin in humans is primarily depending on the sugar moiety. To a minor extent, the plant matrix influences both rate and extent of absorption in the case of buckwheat tea administration compared to the isolated compound. The site of absorption seems to be different for quercetin-4‘-O-glucoside and quercetin-3-O-rutinoside. The significance of specific carriers on the absorption of quercetin glycosides as well as specific intestinal ß-glucosidases needs to be further evaluated.

The experiments in this thesis tested <i>in vitro</i> and <i>in vivo</i> the proposal that zinc-deficient superoxide dismutase, resulting from mutations or oxidative damage to the enzyme, gains ascorbate oxidase activity that contributes to the pathology of amyotrophic lateral sclerosis (ALS). They also tested whether flavonoids can help protect against this activity.<p>The <i>in vitro</i> experiments showed that zinc-extracted Cu/Zn-SOD (Cu-SOD) as well as SOD treated with H2O2 or H2O2 plus ascorbate accelerated ascorbate oxidation 100 to 300 %, while native SOD had no effect. With Cu-SOD, the activity was unaffected by EDTA, EGTA, or catalase, showing that the catalytic copper was firmly bound and that the H2O2 product of SOD activity was not responsible. Catechin and uric acid slowed ascorbate oxidation by Cu-SOD by 72% and 67%, respectively.<p>The <i>in vivo</i> study investigated tissue levels of ascorbate and biomarkers of oxidative stress in a transgenic mice bearing a mutation in Cu/Zn-SOD as a model of familial ALS (FALS mice), and the effects of dietary ascorbate and quercetin. In FALS mice on control modified AIN93G diet for 10 weeks compared to the wild-type, liver thiobarbituric acid reactive substances (TBARS) were 47% higher and liver oxidized vitamin C was 2800% higher. These results support, in liver, that mutant SOD acquired ascorbate oxidase activity and increased oxidative stress. The only difference in other tissues was a 136% increase in GSH/GSSG ratio in thigh muscle of FALS mice.<p>In dietary treatments of FALS mice, spinal cord TBARS was 93 % higher with ascorbate-supplemented diet compared to control diet, suggesting that dietary ascorbate increased oxidative stress. Also in spinal cord, oxidized-vitamin C was 250% higher in ascorbate + quercetin-fed FALS mice, which suggests there is no protection by quercetin against ascorbate oxidation. In brain, protein thiols were 56% and 58% lower in quercetin-fed and ascorbate + quercetin-fed FALS mice, suggesting that quercetin worsened oxidative damage. In liver, quercetin feeding produced a 40% decrease in vitamin C, total vitamin C and oxidized-vitamin C, perhaps by down-regulating ascorbate biosynthesis. Overall the results support a gain of ascorbate oxidase activity of mutant SOD in ALS, but do not support protection by dietary treatment with ascorbate or quercetin.

The experiments in this thesis tested <i>in vitro</i> and <i>in vivo</i> the proposal that zinc-deficient superoxide dismutase, resulting from mutations or oxidative damage to the enzyme, gains ascorbate oxidase activity that contributes to the pathology of amyotrophic lateral sclerosis (ALS). They also tested whether flavonoids can help protect against this activity.<p>The <i>in vitro</i> experiments showed that zinc-extracted Cu/Zn-SOD (Cu-SOD) as well as SOD treated with H2O2 or H2O2 plus ascorbate accelerated ascorbate oxidation 100 to 300 %, while native SOD had no effect. With Cu-SOD, the activity was unaffected by EDTA, EGTA, or catalase, showing that the catalytic copper was firmly bound and that the H2O2 product of SOD activity was not responsible. Catechin and uric acid slowed ascorbate oxidation by Cu-SOD by 72% and 67%, respectively.<p>The <i>in vivo</i> study investigated tissue levels of ascorbate and biomarkers of oxidative stress in a transgenic mice bearing a mutation in Cu/Zn-SOD as a model of familial ALS (FALS mice), and the effects of dietary ascorbate and quercetin. In FALS mice on control modified AIN93G diet for 10 weeks compared to the wild-type, liver thiobarbituric acid reactive substances (TBARS) were 47% higher and liver oxidized vitamin C was 2800% higher. These results support, in liver, that mutant SOD acquired ascorbate oxidase activity and increased oxidative stress. The only difference in other tissues was a 136% increase in GSH/GSSG ratio in thigh muscle of FALS mice.<p>In dietary treatments of FALS mice, spinal cord TBARS was 93 % higher with ascorbate-supplemented diet compared to control diet, suggesting that dietary ascorbate increased oxidative stress. Also in spinal cord, oxidized-vitamin C was 250% higher in ascorbate + quercetin-fed FALS mice, which suggests there is no protection by quercetin against ascorbate oxidation. In brain, protein thiols were 56% and 58% lower in quercetin-fed and ascorbate + quercetin-fed FALS mice, suggesting that quercetin worsened oxidative damage. In liver, quercetin feeding produced a 40% decrease in vitamin C, total vitamin C and oxidized-vitamin C, perhaps by down-regulating ascorbate biosynthesis. Overall the results support a gain of ascorbate oxidase activity of mutant SOD in ALS, but do not support protection by dietary treatment with ascorbate or quercetin.

Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Animal Sciences." Includes bibliographical references (p. 48-51).

Thesis (M.S.)--Oregon State University, 1995. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Orientador: Maria Stella Gonçalves Raddi / Banca: Mariza Landgraf / Banca: Karina Ferrazzoli Devienne / Resumo: Esse estudo foi realizado com o objetivo de avaliar o efeito da concentração subinibitória de quercetina sobre alguns fatores relacionados à virulência de Staphylococcus aureus (ATCC 25923). A atividade antibacteriana foi determinada através do método de microdiluição em caldo e a concentração de 40μg/mL de quercetina foi utilizada como sub-inibitória. O sobrenadante de culturas de S. aureus em BHI contendo quercetina diminuiu a atividade hemolítica para hemácias de carneiro mas não alterou a atividade de citolisinas extracelulares para células de linhagem contínua (células McCoy B ATCC 1696) quando comparado com o sobrenadante da cultura na ausência do flavonol. O efeito da quercetina na fagocitose do S. aureus por polimorfonucleares neutrófilos (PMN) foi determinado através de técnica quimiluminescente. O burst oxidativo de PMN foi estatisticamente significativo para bactérias tratadas em relação às não tratadas, demonstrando que S. aureus crescidos na presença de quercetina tornam-se menos susceptíveis à fagocitose. A inibição da expressão de fatores relacionados à adesão bacteriana foi evidenciada através dos experimentos de fagocitose/adesão em microscopia óptica (1.000x). Mesmo que a quercetina, abaixo da concentração inibitória, tenha pouco efeito sobre a viabilidade de S. aureus, o conhecimento de que esse flavonol é capaz de alterar a adesão de estafilicocos à superfície celular parece ser atrativo para a sua utilização como profilático em processos infecciosos, visto que a adesão é o primeiro passo na patogênese da infecção bacteriana. Entretanto, deve-se considerar sua interferência com a atividade de células fagocíticas, uma importante função do sistema imune do hospedeiro. / Abstract: The aim of this study was to evaluate the effects of quercetin at sub-inhibitory concentration on some Staphylococcus aureus (ATCC 25923) factors related to the virulence. The antibacterial activity of quercetin was evaluated by broth microdilution method and the concentration of 40 μg/mL was used as sub- inhibitory. S. aureus BHI culture supernatant containing quercetin reduced the hemolytic activity for sheep erythrocytes but did not exhibit a detectable change in cytolysin extracellular activity on continuous cell lines (McCoy B cells ATCC 1696) when compared with quercetin-free medium. The effect of quercetin-grown staphylococci phagocytosis by polymorphonuclear neutrophils (PMN) was compared with the effect on non-treated bacteria by chemiluminescence assay. The level of oxidative burst of PMN was statistically different in untreated versus quercetin-treated bacteria showing that druggrown cells became less susceptible to phagocytic uptake. The inhibition of expression of factors related bacterial adhesion was established though adesion/phagocytosis experiments by optical microscopy (1.000x). Even if quercetin at low level has little effect on S. aureus viability, the knowledge that this flavonol is able to affect the properties of staphylococci adherence to cell surfaces may be an attractive advance for its applications as prophylactic in infectious process, considering that bacterial adherence is the initial event in the pathogenesis of bacterial infection. Conversely, it also interferes with the activities of phagocytic cells, an important function of host immune system. / Mestre

Lung cancer has a high incidence rate globally and the leading cause of cancer related mortalities. In 2018, lung cancer has been estimated to cause 1.76 million deaths worldwide (18.33% of total cancer mortalities). In Hong Kong lung cancer has been a leading cause of cancer related deaths, and in 2016 caused 3780 deaths (26.6% of total cancer mortalities). Non-small cell lung cancer (NSCLC) is the major (~85%) lung cancer type, and five-year survival rate for lung cancer has estimated to be 18%. Thus, an efficient lung cancer treatment with lesser adverse effects is need of the hour. In this connection, active targeting of overexpressed receptors at lung tumor site with a ligand functionalized drug delivery system is the current approach, and pulmonary administration could augment chemotherapeutic effect of the drug through localized administration, minimizing the off-target effects by retention of the drug in lungs.Quercetin (QR), a natural flavonoid present in edible fruits and vegetables possess anticancer activity i.e. inhibits lung cancer growth. However, the application of QR in lung cancer therapy has been restricted by various factors i.e. low water solubility (2.15 µg/ml at room temperature), low bioavailability and rapid plasma clearance. To overcome the issues, we have formulated various QR-loaded liposomes surface functionalized with transferrin receptor (TFR) targeting peptides i.e. T7 (HAIYPRH) and T12 (THRPPMWSPVWP) in two research projects with active targeting ability, prolonged circulation time, and sustained release behavior for lung cancer specific QR delivery. In first research project, T7 targeted liposomes with different peptide densities i.e. 0.5%, 1% and 2% and QR-lip (non-targeted) were formulated. TFRs are over expressed (~100 folds) in various cancers including lung cancer and have low expression in most normal cells. T7 surface-functionalized liposomes (2% T7-QR-lip) demonstrated significantly enhanced cytotoxicity (~3-folds), cellular-uptake, S-phase cell cycle arrest and apoptosis in A549 cells. However, in MRC-5 (normal-lung fibroblast) cells no significant difference was observed after treatment with T7-QR-lip and QR-lip in cytotoxicity and cellular uptake studies. In tumor spheroid penetration and inhibition studies, T7 targeted liposomes showed deeper penetration and pronounced inhibition. In vivo biodistribution study via pulmonary administration of T7-DiR-lip has demonstrated liposomes accumulation in the lungs and sustained-release behavior upto 96h. Further, T7-QR-lip significantly enhanced anticancer activity of QR and life-span of orthotopic lung-tumor bearing mice (**p < 0.01, compared with control) via pulmonary administration. In second research project, T12 surface-functionalized liposomes with 0.5%, 1% and 2% T12 peptide densities and QR-lip have been formulated with ~95 % encapsulation efficiency. In vitro drug release study showed sustained release of QR from T12-QR-lip and QR-lip. In vitro experiments showed A549 cells treatment with 2% T12-QR-lip enhanced cellular-uptake, in vitro cytotoxicity, induced apoptosis and S-phase cell cycle arrest due to TFR mediated endocytosis. No significant variation has been observed in cellular-uptake and cytotoxicity after MRC-5 cells were treated with T12-QR-lip and QR-lip. Further, T12-Cou6-lip showed significantly deeper penetration i.e. 120 µm in 3D lung tumor-spheroids. Biodistribution study showed retention of T12-DiR-lip and DiR-lip mainly in the lungs upto 96h after pulmonary administration, as compared to free DiR. Pulmonary administration of T12-QR-lip showed the strongest tumor growth inhibition and survival time of orthotopic lung tumor implanted mice without any systemic toxicity as compared to QR-lip and free-QR. In summary, in vitro and in vivo results of the two research projects suggest that surface functionalization of the liposomes with TFR targeting peptides i.e. T7 and T12 is a promising approach for lung cancer therapy through active targeting and receptor mediated endocytosis of QR at lung tumor site. Moreover, T7 and T12 functionalized liposomes provides a potential drug delivery system for a range of anticancer drugs to enhance their therapeutic efficacy by localized i.e. pulmonary administration and targeted delivery.

Over 270 million people play soccer worldwide, and its popularity grows every day. In team sport exercise, fatigue may result from numerous factors including limited fuel, depleted energy stores and production of compounds that promote an inflammatory response. While inflammation is an essential mechanism for repairing damaged muscle tissue with exercise, prolonged inflammation leads to increased production of reactive oxygen species that can damage cell membranes, muscle, and signaling proteins. To prevent this response and improve performance, athletes are increasingly looking to nutritional interventions. Carbohydrate and antioxidant supplementation have both shown evidence of producing an ergogenic effect and attenuating inflammation and oxidative stress with prolonged endurance exercise. Less is known about how these interventions may influence intermittent, high-intensity exercise characteristic of soccer. In particular, this exercise presents a unique challenge in that opportunities for nutrient intake are limited to pre-game and half-time. In our first study, we had 10 male collegiate soccer players perform a 90-min. soccer-simulation test, that we developed, which was followed by a progressive shuttle run (PSR) test to exhaustion. They consumed a honey-sweetened beverage (H), a sports drink (S), or a placebo (P) before and half-way through the protocol. Both H and S provided 1.0 g·kg⁻¹ carbohydrate and ~17.6 mL·kg⁻¹ total volume for each trial. Overall, the test resulted in increased fatigue and production of inflammatory markers and antioxidant capacity. There was no significant difference between treatments for any performance measure. Mean times for a high intensity run and rating of perceived exertion increased with time, and there was an overall decrease in PSR time compared to baseline (-22.9%). There was a rise in glucose (15.6%), IL-6 (548%), IL-1ra, IL-10 (514%) and ORAC (15%) post-test but no change in cortisol. Insulin was significantly lower by 1 h-post. IL-1ra levels increased post-test for H (25.8%), S (65.5%), and P (63.9%), but the change for H was less than the other treatments. No treatment effects for the other blood measures were observed. The lack of an ergogenic effect of carbohydrate on soccer performance calls into question the benefit of supplementation at a frequency typical of a regulation soccer match in highly trained athletes with adequate energy stores. Since acute carbohydrate ingestion in the first study did not attenuate some markers of inflammation (e.g. IL-6), we chose to focus on an alternative theory for the rise in inflammatory markers with strenuous exercise in our second study. One aspect of soccer, repeated sprinting, results in increased ROS production partially through the activation of the enzyme xanthine oxidase (XO). Quercetin, a flavonol in plants that has shown some ergogenic effects with endurance exercise, inhibits XO in vitro. The effect of quercetin on team sport exercise had not been studied. We gave recreationally active males a commercial sports drink (S) or S + 500 mg of quercetin (Q) 2x/d for 1 wk prior to a repeated sprint test (RST). Sprint times increased (5.9%) for both treatments as did plasma XO activity (47%), IL-6 (77%), and uric acid (25%) from pre-test to post-test. Q supplementation did not attenuate plasma XO activity or IL-6 and actually increased one calculated index of fatigue, percent fatigue decrement (5.1%- Q and 3.8%- P). These findings add to the growing body of literature that quercetin supplementation does not attenuate exercise-induced inflammation and oxidative stress in vivo. Collectively, this research has practical implications for sports drink companies who are exploring the use of flavonoid compounds in product formulation. Specifically, they should reconsider adding quercetin to their beverages if they are marketing to team sport athletes. Also, soccer players should be made aware that, at ingestion frequencies typical of a soccer match, they may not expect a significant performance benefit from acute carbohydrate supplementation. / Ph. D.

M.Sc. Thesis Dissertation, August 2019, McMaster University / Renal dysplasia, defined as the abnormal development of kidney tissue, is the leading cause of kidney disease in children. While there are numerous causes of renal dysplasia (i.e. genetic, environmental and epigenetic factors), there is no cure to this abnormal defect. Kidney development occurs by two main processes: branching morphogenesis, which forms the collecting duct system, and nephrogenesis, which generates the nephrons, the functional units of the kidney. Our previous studies have demonstrated that β-catenin, a dual-function protein involved in cell adhesion and gene transcription, regulates branching morphogenesis and nephrogenesis. Furthermore, we discovered that nuclear β-catenin levels are increased in kidneys from patients with renal dysplasia, suggesting β-catenin can be a potential therapeutic target to modulate kidney development and renal dysplasia. Quercetin is a flavonoid that reduces β-catenin levels and inhibits its transcriptional activity, leading to improved outcomes in cancer and in kidney fibrosis. The role of quercetin in kidney development and in abnormal defects that arise during kidney development is yet to be examined. Using embryonic mouse kidney organ culture, I found that quercetin treatment resulted in a dose-dependent disruption in branching morphogenesis and nephrogenesis. In addition, quantitative reverse-transcriptase PCR revealed a decreased expression of β-catenin target genes essential for kidney development (i.e. Pax2, Six2 and GDNF). Immunohistochemistry for β-catenin demonstrated that quercetin reduced nuclear β-catenin expression and increased cytoplasmic and membrane-bound expression in a dose-dependent manner. These results were confirmed by Western blot analysis. These novel findings demonstrate that quercetin treatment resulted in decreased levels of nuclear β-catenin, resulting in a decrease in its transcriptional activity which manifested in alterations in kidney developmental processes, suggesting quercetin is effective at reducing nuclear β-catenin in wild-type embryonic kidneys. Next, to determine whether quercetin has any effects on renal dysplasia, I utilized transgenic mice models that overexpress β-catenin in select cells of the embryonic kidney. These models recapitulate the defects observed in human renal dysplasia, including disorganized branching morphogenesis and disrupted nephrogenesis. Quercetin treatment of embryonic dysplastic kidneys resulted in a partial rescue of renal dysplasia which was evident in marked improvements in branching morphogenesis and nephrogenesis, as well as an increase in the number of properly-developing nephrons in the kidney tissue. Analysis of β-catenin expression in quercetin-treated dysplastic kidneys revealed a decrease in nuclear levels and an increase in cytoplasmic and membrane-bound levels, resulting in a reduced expression of target genes (Pax2, Six2, and GDNF). Finally, this partial rescue of renal dysplasia was associated with an improved and organized E-cadherin expression in quercetin-treated dysplastic kidneys, suggesting a possible molecular mechanism of quercetin action in resolving abnormal kidney development. Overall, my findings demonstrate, for the first time, that quercetin reduces β-catenin transcriptional activity in normal and dysplastic kidneys and reduces the severity of defects in renal dysplasia. / Thesis / Master of Science in Medical Sciences (MSMS)