<p>Lung cancer is the leading cause of cancer related deaths in both the US and Canada and efforts still need to be made towards understanding the disease. The role of inflammation in the promotion of cancer development represents a newer avenue of research. The glycoprotein (gp)-130 cytokine interleukin-6 (IL-6) has a well established role in promoting inflammation and recent evidence suggests roles in development of certain tumors in animal models. Less is known of the related family member oncostatin M (OSM) and the functions of either IL-6 or OSM in lung cancer development is not known. Based on the hypothesis that these cytokines promote lung cancer development, IL-6 and OSM were overexpressed in the lungs of two separate mouse models for lung cancer utilizing adenovirus vectors encoding IL-6 or OSM. The first mouse model utilized a Cre-conditional oncogene KRAS G12D (developed by Tyler Jacks) in which endotracheal administration of adenovirus (Ad)-encoded Cre-recombinase resulted in increases in lung densities in a dose-dependent fashion over a period of 6 weeks that were measurable by CT scanning and histology. Increases in cytokines IL-6 and kertinocyte chemoattractant (KC) were detectable in the bronchoalveolar lavage (BAL) by week 4, as well as marked increases in alveolar macrophage numbers. Macrophages were also shown as a possible target for Cre-mediated recombination and mutant KRAS expression. Administration of either AdIL-6 or AdOSM as well as AdCre resulted in a trend toward increases in tumor burden with AdOSM based on experiments terminated at 4 weeks. The second mouse model involved endotracheal administration of the lewis lung carcinoma (LLC) cell line, which after 7 days resulted in detectable tumor burden. Administration of either AdIL-6 or AdOSM and LLC cells simultaneously was shown to increase tumor burden relative to AdDl70 co-administration. These results suggest a possible role of IL-6 or OSM in promoting lung tumor development in animal models and may ultimately reveal gp130 cytokines IL-6 or OSM as a possible therapeutic target for the treatment of lung cancer.</p> / Master of Science (MSc)

<p>Class A scavenger receptors are multifunctional transmembrane glycoproteins that mediate macrophage functions like phagocytosis and endocytosis. The macrophage receptor with collagenous structure (MARCO) is one such receptor. It has been shown that the extracellular cysteine-rich domain of MARCO is responsible for ligand binding, but the role of the cytoplasmic domain in ligand uptake is unclear. The aim of the studies presented in this thesis is to characterize the role of the cytoplasmic domain of MARCO and to characterize the molecular pathway of MARCO-mediated endocytosis.</p> <p>Full-length human MARCO (hMARCO) and Δ1-34hMARCO, which lacks the first thirty-four amino acids were created in order to determine whether amino acids 1-34 contained residues required for receptor internalization and surface expression. The constructs were stably expressed in HEK293T cells and found to have similar levels of surface expression and same rate of internalization without ligand. Interestingly, hMARCO, but not Δ1-34hMARCO, surface expression was up-regulated upon ligand incubation.</p> <p>In order to ascertain the importance of clathrin, dynamin and actin in MARCO-mediated endocytosis, specific endocytic inhibitors were used. MARCO-mediated ligand uptake was inhibited when clathrin and actin polymerization and, dynamin functions were impaired by these inhibitors. Furthermore, ligand uptake by Δ1-34hMARCO-expressing HEK293T was insensitive to inhibitors of clthrin and dynamin but not inhibitors of actin.</p> <p>In conclusion, MARCO mediates endocytosis via a clathrin-mediated, dynamin-dependent pathway that involves actin. Amino acids 1-34, are required clathrin and dynamin but not actin functions during MARCO-mediated endocytosis. Additionally, amino acids 1-34 might also be important for MARCO recycling but not receptor internalization or surface expression.</p> / Master of Science (MSc)

<p>Obesity is a major global health concern and is associated with the development of numerous non-communicable diseases. A thorough understanding of the onset of obesity is critical to the development of effective therapeutic strategies against this disease state. Recently, obesity has been described as a complex disease characterized by chronic low grade inflammation. Abnormal adipose tissue expansion is accompanied by an increased presence of proinflammatory immune cells, dysregulated adipokine expression, oxidative stress, and is associated with significant changes in the bacterial composition of the gut. While interleukin-15 (IL-15) has been studied extensively for its immunological effects, this cytokine has recently been shown to influence body weight and fat mass. The focus of this thesis was to elucidate the role of and mechanism by which IL-15 modulates adipose tissue. Our first study demonstrated that low levels of IL-15 expression are associated with adiposity and promotes an obese state in IL-15-/- mice and human subjects, while IL-15 overexpression was associated with a lean phenotype in IL-15tg mice when compared to appropriate controls. To uncover the underlining mechanisms by which IL- 15 mediates differences in body weight, we subsequently determined that IL-15 mediated weight loss occurred independently of lymphocytes. In another study, we showed that IL-15tg mice had increased mitochondrial activity and mass specific to adipose tissue compared to IL-15-/- and B6 mice, while acute IL-15 administration induced the expression of FAO markers in adipose tissue. Lastly, IL-15 treatment increased mitochondrial membrane potential and decreased lipid deposition in cultured adipocytes, suggesting that IL-15 may mediate its effects directly on adipose tissue. The experimental results presented in this thesis demonstrate that IL-15 is an important regulator of adipose tissue and body weight. Future studies examining the effects of IL- 15 on adipose tissue will further our knowledge on IL-15 biology, and may contribute to novel therapeutic strategies for the treatment and prevention of obesity.</p> / Doctor of Philosophy (PhD)

Prior work in this system has indicated that, under favourable conditions, the formation of a martensitic transformation product on cooling may be preceded by a second-order cubic-rhombohedral transformation. In the present investigation, thin-film electron microscopy and diffraction have been employed to study the pre-transformation phenomena in the temperature range 20-300 °C. The results are interpreted in terms of localized thermal diffuse scattering, resulting from the transformation, in terms of lattice dynamics, is suggested. dark field micrographs of the rhombohedral phase suggest a moderate degree of co-operation between adjacent domains. Additional data is provided in the form of volumetric and x-ray intensity measurements. / Thesis / Master of Engineering (ME)

Prior work in this system has indicated that, under favourable conditions, the formation of a martensitic transformation product on cooling may be preceded by a second-order cubic-rhombohedral transformation. In the present investigation, thin film electron microscopy and diffraction have been employed to study the pre-transformation phenomena in the temperature range 20-300°C. The results are interpreted in terms of localized thermal diffuse scattering, resulting from incipient mechanical instability. A model for the cubic-rhombohedral transformation of the rhombohedral phase suggest a moderate degree of co-operation between adjacent domains. Additional data is provided in the form of volumetric and x-ray intensity measurements. / Thesis / Master of Engineering (ME)

Adipose tissue is an endocrine organ, and its homeostatic mechanisms in normal weight, overweight and obese subjects must be elucidated. We sought to determine the basal adipose tissue biology of visceral (VIF) and subcutaneous (SQF) fat depots in 8 month old Sinclair minipigs, an animal that has been shown to be physiologically similar to humans. Metabolic analysis showed a decrease in LDL, white blood cells (WBC), and lymphocyte percentages as the minipigs aged from 6 to 8 months (p <0.0001 and = 0.0046 and 0.0165 respectively). There were no significant changes in triglycerides, HDL, VLDL, and neutrophil percentages. There was a trend in insulin increase (P=0.0722). Microarray analysis was performed to determine transcriptome differences between VIF and SQF. When VIF was compared to SQF, expression of a total of 788 transcript ID’s differed: were 240 up-regulated and 548 down-regulated. Examples included hydroxysteroid 11-beta dehydrogenase 2, fatty acid synthase, IL-18, and platelet factor 4 which were all up-regulated in VIF vs. SQF. The down-regulated transcripts included estrogen receptor 1, insulin-like growth factor binding protein 5, and platelet derived growth factor D. When SQF was compared to VIF, a total of 598 transcript IDs were up or down-regulated by more than a 2 fold difference (P<0.05). From this subset of the transcriptome, we found 471 IDs were up-regulated in SQ fat, and 127 were down- regulated. Interestingly, the up-regulated genes included prostaglandin F2 receptor negative regulator, estrogen receptor 1, thrombospondin 1, lipoprotein related receptor protein 2, and platelet derived growth factor D. Down-regulated genes in SQF compared to VIF included IL-18, platelet factor 4, cyclooxygenase, and fatty acid synthase. We found no significant difference in gene expression between SQF and VIF TNF alpha, TLR 4, and adiponectin in our. Immunofluorensce (IF) assay revealed that SQF expressed more CD 163 positive (alternatively activated) macrophages than VIF, and little to no CD 68 (classically activated) positive macrophages. Additionally, VIF expressed more CD 68 positive macrophages compared to SQF. The data from this study is consistent with the human and rodent literature which states that VIF is more metabolically active and pro-inflammatory compared to SQF.

Adipose tissue is an endocrine organ, and its homeostatic mechanisms in normal weight, overweight and obese subjects must be elucidated. We sought to determine the basal adipose tissue biology of visceral (VIF) and subcutaneous (SQF) fat depots in 8 month old Sinclair minipigs, an animal that has been shown to be physiologically similar to humans.Metabolic analysis showed a decrease in LDL, white blood cells (WBC), and lymphocyte percentages as the minipigs aged from 6 to 8 months (p <0.0001 and = 0.0046 and 0.0165 respectively). There were no significant changes in triglycerides, HDL, VLDL, and neutrophil percentages. There was a trend in insulin increase (P=0.0722).Microarray analysis was performed to determine transcriptome differences between VIF and SQF. When VIF was compared to SQF, expression of a total of 788 transcript ID’s differed: were 240 up-regulated and 548 down-regulated. Examples included hydroxysteroid 11-beta dehydrogenase 2, fatty acid synthase, IL-18, and platelet factor 4 which were all up-regulated in VIF vs. SQF. The down-regulated transcripts included estrogen receptor 1, insulin-like growth factor binding protein 5, and platelet derived growth factor D. When SQF was compared to VIF, a total of 598 transcript IDs were up or down-regulated by more than a 2 fold difference (P<0.05). From this subset of the transcriptome, we found 471 IDs were up-regulated in SQ fat, and 127 were down- regulated. Interestingly, the up-regulated genes included prostaglandin F2 receptor negative regulator, estrogen receptor 1, thrombospondin 1, lipoprotein related receptor protein 2, and platelet derived growth factor D. Down-regulated genes in SQF compared to VIF included IL-18, platelet factor 4, cyclooxygenase, and fatty acid synthase. We found no significant difference in gene expression between SQF and VIF TNF alpha, TLR 4, and adiponectin in our. Immunofluorensce (IF) assay revealed that SQF expressed more CD 163 positive (alternatively activated) macrophages than VIF, and little to no CD 68 (classically activated) positive macrophages. Additionally, VIF expressed more CD 68 positive macrophages compared to SQF. The data from this study is consistent with the human and rodent literature which states that VIF is more metabolically active and pro-inflammatory compared to SQF.

Electronic cigarette usage is becoming increasingly prevalent among school age children and young adults. A known bactericidal agent, propylene glycol, is often used as a carrier for nicotine, flavoring, and additional constituents of electronic cigarette juice. This study examined the relationship between propylene glycol and virulence gene expression in Streptococcus pyogenes, a respiratory tract pathogen commonly found in school-age individuals. A variety of virulence genes controlled by the three stand alone regulators mga, RofA, and Rgg/RopB were sampled in an effort to understand the pathway by which virulence is affected. The genes chosen encode C5a peptidase, fibronectin binding protein, hyaluronate lyase, NAD glycohydrolase, Streptococcal pyrogenic exotoxin A and B, streptodornase, streptokinase, Streptolysin O, and Streptolysin S. No significant change in gene expression was observed, but a novel method to test the effects of aerosols on cells was developed. This method can be used in the future to observe the effect of aerosols, including commercial electronic cigarette juice, on both bacterial and mammalian cells.

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Physics / Doctoral / Doctor of Philosophy