Medicine and Health Sciences Commons^™

Development And Evaluation Of A Heterogenous Virus-Like Particle (Vlp) Formulation To Achieve Hiv-1 Latency Reversal And Cure., Joshua P. Pankrac

Electronic Thesis and Dissertation Repository

HIV-1 is the etiological agent behind acquired immune deficiency syndrome (AIDS) – a chronic, life-threatening condition that compromises host immune function. After nearly four decades and despite ongoing global efforts, HIV-1 persists in nearly 38 million individuals worldwide. Of this population, only 60% have access to life-saving combination antiretroviral therapy (cART), clearly emphasizing the need to realize a cure. Unfortunately, the establishment of replication-competent provirus in resting CD4+ T lymphocytes represents a significant barrier to HIV-1 curative research. The viral reservoir is highly stable and has a half-life of ~44 months. Therefore, it is unlikely that infection will naturally exhaust …

Discovery Of Novel Mechanisms Regulating Cancer Extravasation In The Chorioallantoic Membrane Model, Yohan Kim

Electronic Thesis and Dissertation Repository

Cancer metastasis is a multistep process that begins with the invasion of tumour cells into the stroma and migration towards the blood vessels. Tumour cells that have entered the bloodstream must then survive and leave by a process known as extravasation. Finally, extravasated cells proliferate and establish the secondary site in the metastatic cascade. Although extravasation encompasses key events during cancer cell invasion to aid in the development of effective treatments, an in vivo model that rapidly, reproducibly and economically recapitulates cancer cell extravasation is needed. Therefore, the objectives of my research were to 1) establish and validate an in …

The Epidemiology Of Infective Endocarditis Among People Who Inject Drugs In London, Ontario., Brian Hallam

Electronic Thesis and Dissertation Repository

Infective endocarditis is an infectious disease that affects the valves of the heart. Injection drug use is currently a leading risk factor among patients with endocarditis. We conducted a prospective study using data from hospital chart records among patients with endocarditis in London, Ontario, which has a relatively high prevalence of people who inject drugs to assess the severity of the issue and the major risk factors of mortality pertaining to this population. This study had a sample size of 353 and included a review of the incidence of admissions of endocarditis, as well as a survival analysis, using both …

Localization And Trafficking Of Pannexin 1 In Polarized And Non-Polarized Cells, Michelle Shum

Electronic Thesis and Dissertation Repository

The channel-forming membrane protein pannexin 1 (Panx1) is best characterized as an ATP release channel and has been linked to over a dozen human pathologies. Along with protein- protein interactions and post-translational modifications, the physiological function of Panx1 channels is highly dictated by its subcellular localization. In polarized epithelial cells in vivo, Panx1 is reported to selectively localize to distinct plasma membrane domains. Here, we investigated whether this polarized distribution is guided by internal motifs contained within the Panx1 polypeptide. In polarized MDCK cells, Panx1 was localized predominantly at the apical membrane domain, although a subset remained detectable in the …

Inhibition Of Nk Cell-Mediated Cytotoxicity By Tubular Epithelial Cell Expression Of Clr Proteins, Benjamin B. Fuhrmann

Electronic Thesis and Dissertation Repository

Cytotoxic effector cells can target and kill parenchymal cells of the kidney which results in injury and loss of function. Endogenous regulatory systems may exist to attenuate Natural Killer (NK) and other effector cell activation and cytotoxicity in diverse conditions, including ischemia-reperfusion injury associated with kidney transplantation. Understanding these mechanisms will direct new therapeutic strategies. Kidney tubular epithelial cells (TEC), the predominant cell type in kidneys, may negatively regulate NK cell activation by surface expression of C-type lectin-related proteins (Clr). Clr-b and -f were found to be expressed by wild type (WT) TEC. Clr-b was upregulated by …

Identification And Characterization Of Hiv-1 Antagonists To The Antiviral Protein, Herc5, Divjyot S. Kochar

Electronic Thesis and Dissertation Repository

Interferons that trigger the release of innate antiviral proteins are a vital immune defense mechanism against viruses such as HIV-1. HERC5, an interferon stimulated protein inhibits HIV-1 replication through two independent mechanisms: inhibiting export of HIV-1 RNA through the Rev-dependent pathway and blocking an early step in the assembly of the virion. HERC5 is an antiviral protein yet individuals infected with HIV fail to control the infection. This can be due to viral antagonist mechanisms which counteract the function of restriction factors. Using a viral particle release assay, I discovered HIV-1 Env and Vpu can function as potential antagonists to …

Prostate Cancer Microparticles In Men Undergoing Radical Prostatectomy, Malcolm James Dewar

Electronic Thesis and Dissertation Repository

Objectives: To determine changes in prostate microparticle (PMP) concentrations in men with prostate cancer (PCa) after digital rectal examination (DRE), after radical prostatectomy (RP), and at follow-up.

Materials and Methods: 22 men were recruited before RP. Four blood specimens were collected – baseline (specimen 1), post-DRE (specimen 2), immediately post-RP (specimen 3), and follow-up (specimen 4). Pre- and post-DRE urine was collected (Specimen A and B respectively). Flow cytometric analysis of biofluids was performed with fluorescent-labeled antibodies against prostate-specific membrane antigen (PSMA) and polysialic acid. Total MP (TMP) and dual positive (PMP) events per µl of plasma or urine were …

Neuronal Correlates For Neuroendocrine Habituation To Repeated Stress, Sara Matovic

Electronic Thesis and Dissertation Repository

One way that the body actively responds to an impending stressor is by increasing systemic glucocorticoids through the activation of the hypothalamic-pituitary-adrenal (HPA) axis. While it is essential for short-term adaptation to stress, the sustained activation of the HPA axis during chronic stress can be detrimental and is linked to stress-related psychiatric conditions such as anxiety and depression. Therefore, it is important that the HPA axis adapts, or habituates, during chronic stress to minimize the negative consequences. Corticotropin releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) function to assimilate incoming information from the stress circuitry and …

Therapeutic Application Of Carbon Monoxide In Acute Limb Compartment Syndrome, Aurelia Bihari

Electronic Thesis and Dissertation Repository

Acute limb compartment syndrome (CS), a devastating complication of musculoskeletal trauma, develops in response to elevation of the pressure within a closed osseofascial compartment, producing muscle- and limb-threatening ischemia. Full decompression of all involved compartments by fasciotomy is the current gold-standard therapy, but it must be performed within a surgical window of 6-8 hours, before tissue damage becomes permanent.

Carbon monoxide (CO), a byproduct of heme metabolism, has been shown protective in ischemia. While inhalation of CO leads to elevation of carboxyhemoglobin (COHb), recent development of transitional metal carbonyls, CO-releasing molecules (CO-RMs), particularly the water-soluble CORM-3, delivers CO in a …

Mt1-Mmp Mediates The Migratory And Tumourigenic Potential Of Breast Cancer Cells Via Non-Proteolytic Mechanisms, Mario Cepeda

Electronic Thesis and Dissertation Repository

Membrane Type-1 Matrix Metalloproteinase (MT1-MMP) is a multifunctional protease that affects cell function via proteolytic and non-proteolytic mechanisms such as promoting degradation of the extracellular matrix (ECM) or augmentation of cell migration and viability, respectively. MT1-MMP has been implicated in metastatic progression ostensibly due to its ability to degrade ECM components and to allow migration of cells through the basement membrane. Despite in vitro studies demonstrating this principle, this knowledge has not translated into the use of MMP inhibitors (MMPi) that inhibit substrate catalysis as effective cancer therapeutics, or been corroborated by evidence of in vivo ECM degradation mediated by …

Investigating Stromal Contributions To The Regulation Of Cancer Progression, Krista M. Vincent

Electronic Thesis and Dissertation Repository

Tumours are not insular masses of proliferating cells, rather tumour cells evolve within a complex local environment complete with matrix, stromal, and immune components. Therefore, successful tumour growth and eventual metastasis is not determined solely by tumour cells themselves, but also by the fitness advantage or disadvantage conferred by their local environment. However, many of our current cancer models are composed solely of tumour cell isolates. As tumour fitness is dependent on the entire local cellular context, we were interested in characterizing the accuracy of cell lines as models of the tumour microenvironment, with a focus on the secreted Frizzled-related …

Characterization Of The Nicotine-Induced Endoplasmic Reticulum Stress Response In The Rat Placenta In Vivo And In Vitro, Michael Ka Chun Wong

Electronic Thesis and Dissertation Repository

Nicotine exposure during pregnancy leads to adverse health outcomes, including compromised placental development. Although the molecular mechanisms remain elusive, recent studies identified that endoplasmic reticulum (ER) stress may underlie poor placentation. Therefore, we were interested in investigating the effects of nicotine exposure on the ER stress response in the placenta. A well-established maternal nicotine exposure rat model and Rcho-1 trophoblast giant cell model were utilized to address the research questions. Maternal nicotine exposure in vivo led to elevated ER stress in association with impaired disulfide bond formation and hypoxia. Nicotine exposure in vitro further differentiated that ER stress may be …

Investigating The Role Of Hydrogen Sulfide In The Survival, Growth And Angiogenic Potential Of Clear Cell Renal Cell Carcinoma Cell Lines And Xenografts, Eric Sonke

Electronic Thesis and Dissertation Repository

Clear cell renal cell carcinoma (ccRCC) is characterized by Von Hippel-Lindau (VHL)-deficiency, resulting in pseudohypoxic, angiogenic and glycolytic tumours. Hydrogen sulfide (H₂S) is an endogenously-produced gasotransmitter that accumulates under hypoxia and has been shown to be pro-angiogenic and cytoprotective in cancer. It was hypothesized that H₂S levels are elevated in VHL-deficient ccRCC, contributing to survival, metabolism, and angiogenesis. Using H₂S-specific probes, it was found that H₂S levels were higher in VHL-deficient ccRCC cell lines compared to cells with wild-type VHL. Inhibition of H₂S-producing enzymes could reduce the proliferation, metabolism …

Protective Effect Of Modified Human Fibroblast Growth Factor On Diabetic Nephropathy, Ana M. Pena Diaz

Electronic Thesis and Dissertation Repository

Oxidative stress is a key mechanism causing Diabetic Nephropathy (DN). Acidic fibroblast growth factor (aFGF) is known to confer protection from oxidative stress. However, it also has significant angiogenic activity. Hence, we have generated a mutated human acidic FGF (maFGF), with intact antioxidant properties but devoid of angiogenic activities. Recent evidence shows that maFGF treatment prevented diabetic cardiomyopathy and further in vitro studies suggest that this prevention is mediated by suppression of cardiac oxidative stress, hypertrophy and fibrosis. We hypothesized that maFGF treatment has a protective effect in DN.

We show that maFGF treatment did not affect body weight and …

Mirna Regulation Of Programmed Cell Death-1 In T Cells: Potential Prognostic And Therapeutic Markers In Melanoma, Nathan J. Johnston

Electronic Thesis and Dissertation Repository

Immunoinhibitory cell receptors that can induce a state of T cell exhaustion upon exposure to tumor antigen include Programmed Cell Death-1 (PD1). Although much research has been conducted on PD1, global miRNA regulation of PD1 in a cancer model has not been investigated. We hypothesized that miRNAs exist that can silence PD1 in vitro and revert symptoms of T cell exhaustion. Eleven miRNAs were discovered with altered expression between PD1⁺ and PD1^- CD4⁺ T cells from melanoma-bearing mice. miR-28 and miR-107 mimics were shown to bind to and silence the 3’UTR of PD1, and miR-28, miR-150 and …

The Role Of Oxygen Tension And Insulin-Like Growth Factor Signaling In The Placental Mesenchymal Stem Cell Fate, Amer Youssef

Electronic Thesis and Dissertation Repository

The human placenta of different gestational ages is a readily available source for isolation of adult mesenchymal stem cell (MSC) for potential use in regenerative therapies. The chorionic villous region, the largest component of a placenta that interfaces with the maternal circulation, is a rich source of placental MSCs (PMSCs). To remain multipotent, PMSCs are best maintained in culture conditions that mimic the in vivo microenvironment. Insulin like growth factors (IGFs, IGF-I and -II) and oxygen tension are two of the most important microenvironmental factors in the placenta. They are of low concentration or tension respectively, at early gestation, and …

The Effects Of A Single Acute And Repeated Intracerebroventricular Infusions Of Propionic Acid On Locomotor Activity And Neuroinflammation In Rats, Stacey Holbrook

Electronic Thesis and Dissertation Repository

Dietary and gastrointestinal factors may contribute to the etiology of autism spectrum disorders (ASD). Propionic acid (PPA) is a short chain fatty acid that is an intermediary of fatty acid metabolism and a fermentation by-product of enteric bacteria. Using a single infusion (Chapter 2) and repeated infusions (Chapter 3), the temporal relationship between PPA-induced locomotor activity and astrocyte/microglial changes was demonstrated. Adult Long-Evans rats were centrally infused with 4µl of 0.26M PPA or 0.1M PBS vehicle once or once a week for four weeks. Locomotor activity was evaluated for 20 minutes following infusion and again several days later to assess …

Investigation Of Histone Lysine Methylation In Stem Cell Differentiation Using Inhibitor Peptide, Wendy Zhu

Electronic Thesis and Dissertation Repository

In an effort to expand the histone code, we examine a novel site of methylation on lysine 43 of histone H2B. In mouse embryonic stem cells (ESCs), KDM5b acts as the lysine demethylase for H2BK43me2, diminishing this histone mark as cells differentiate. We utilize a synthetic peptide mimetic corresponding to amino acids 37-49 of histone H2B in order to sterically inactivate KDM5b enzyme. The addition of inhibitor peptide into culture enhanced stem cell differentiation, upregulating cell cycle and neural-specific markers while downregulating the expression of pluripotency genes. Global gene analysis patterns of peptide-treated ESCs were representative of differentiated cell populations. …

Metastatic Disease: Interactions Between Tumor Cells And Host Environment During Cancer Cell Spread, Jennifer M. Maclean

Electronic Thesis and Dissertation Repository

Tumor and metastasis formation are not cell autonomous phenomena, but rather an evolution of disease within and responding to the host environment. Metastatic spread from a primary tumor occurs as a result of a complex interplay between tumor cells and the host, wherein tumor cells must escape the primary tumor, enter the host vasculature, travel to and arrest in a distant tissue and survive and grow in that new organ. It is known that cells that progress through these stages must both escape and exploit host systems, yet the mechanisms used are not fully understood. Therefore, the goal of this …