VictorJuiz/thesis huggingface dataset:
Effects of Chronic Maternal Stress on Behaviour and Hypothalamo-pituitary-adrenal Function in Offspring

Maternal stress during the perinatal period has been linked to attention and behavioral problems and increased adrenocortical activity in children. Underlying this relationship is thought to be exposure to excessive glucocorticoids during development. The aim of this set of studies was to determine the effects of chronic maternal stress (CMS) during the perinatal period on behaviour and endocrine function in male and female guinea pig offspring at the juvenile and adult life stage. Environmental enrichment was investigated as a potential therapeutic tool to reverse changes induced by CMS. Pregnant guinea pigs were exposed to a sequence of stressors every other day over the second half of gestation until weaning on postnatal day 25. Offspring were tested for ambulatory activity, attention, cognitive function, sex-steroid levels and adrenocortical function. One cohort of animals were housed in an enriched environment, the remaining offspring were housed in standard conditions. A separate cohort was administered amphetamine (1 mg/kg) prior to behavioural testing to determine influence of CMS on dopaminergic function. Juvenile male and female offspring of mothers exposed to stress exhibited increased basal and decreased stress-induced salivary cortisol, and male offspring displayed reduced activity and a phase shift in their circadian rhythm of activity. Adult male offspring of CMS mothers exhibited increased activity in a novel environment and decreased activity in a familiar environment. Female adult offspring of CMS mothers exhibited reduced attention and increased activity in a novel environment. Enrichment acted independently of CMS, increasing plasma testosterone and attention in adult male offspring and reducing the adrenocortical response to stress and decreasing attention and activity in female offspring. Amphetamine decreased activity in a novel environment and increased activity in a familiar environment in both sexes, regardless of age or maternal treatment. Amphetamine improved attention in juvenile and adult males. The current studies demonstrated a strong effect of CMS on behaviour in juvenile and adult offspring. Enrichment was not effective for attenuating the effects of CMS. These studies clearly demonstrate behavioural changes as a result of CMS emerge over the lifetime of the offspring and have begun to uncover the underlying mechanisms of programming.

Keywords: Maternal Stress
Hypothalamo-Pituitary-Adrenal Axis
Behaviour
Endocrinology
Environmental Enrichment
Programming
Amphetamine
Advisor: Matthews, Stephen
Early Immune Responses to SARS Coronavirus in Ferrets

Severe acute respiratory syndrome (SARS) was defined as an invasive respiratory disease in 2002, which originally came from China and rapidly spread all over the globe. Acute pneumonia and lower respiratory tract involvement most affected the middle aged individuals and elderly with a mortality rate of 11%. While SARS Corona virus (SARS-CoV) has maintained its potential capacity to reemerge, clinical study of the immune system of SARS patients, as well as controlled studies may lead to application of new treatment strategies in future. Throughout this work, I have focused on early immune responses to SARS-CoV in humans and in ferrets. CXCL0 has been associated with alterations in the clinical course of several infectious diseases, including SARS and influenza. Here I have cloned ferret CXCL10 gene and have expressed its recombinant protein. I demonstrate that the CXCL10 plasma level in SARS patients is associated with the severity of disease. I also show that endogenous ferret CXCL10 exhibits similar mRNA expression patterns in the lungs of deceased SARS patients and ferrets experimentally infected with SARS-CoV. Type I interferons (IFNs) are indispensable parts of the innate immunity during early stages of infection. A clear distinction between genes upregulated by direct virus-cell interactions and genes upregulated by secondary IFN production has not been made yet. Here, I have investigated differential gene regulation in ferrets upon subcutaneous administration of IFN-a2b and during SARS-CoV infection. In vivo experiments revealed that IFN-a2b causes upregulation of abundant IFN response genes (IRGs), chemokine receptors, and other genes that participate in phagocytosis and leukocyte migration. SARS-CoV infection of ferrets leads to upregulation of varieties of IRGs and a broad range of genes involved in cell migration and inflammation. This work allowed dissection of several molecular signatures present during SARS-CoV infection, which are part of a robust IFN antiviral response. Since localization of CD8+ Tcells may contribute to tissue injury, I have characterized ferret CD8 gene and have generated reagents that can be used in future studies with the aim of evaluating CD8+ T cells localization in the ferret lung during infection with SARS-CoV.

Keywords: Immunology
Infectious diseases
SARS
Ferret
Chemokines
Interferon
Advisor: Kelvin, David J.
Biological Roles of the Vitamin D Receptor in the Regulation of Transporters and Enzymes on Drug Disposition, Including Cytochrome P450 (CYP7A1) on Cholesterol Metabolism

Nuclear receptors play significant roles in the regulation of transporters and enzymes to balance the level of endogenous molecules and to protect the body from foreign molecules. The vitamin D receptor (VDR) and its natural ligand, 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3], was shown to upregulate rat ileal apical sodium dependent bile acid transporter (Asbt) to increase the reclamation of bile acids, ligands of the farnesoid X receptor (FXR). FXR is considered to be an important, negative regulator of the cholesterol metabolizing enzyme, Cyp7a1, which metabolizes cholesterol to bile acids in the liver. In rats, decreased Cyp7a1 and increased P-glycoprotein/multidrug resistance protein 1 (P-gp/Mdr1) expressions pursuant to 1,25(OH)2D3 treatment was viewed as FXR effects in which hepatic VDR protein is poorly expressed. In contrast, changes in rat intestinal and renal transporters such as multidrug resistance associated proteins (Mrp2, Mrp3, and Mrp4), Asbt, and P-gp after administration of 1,25(OH)2D3 were attributed directly as VDR effects due to higher VDR levels expressed in these tissues. Higher VDR expressions were found among mouse hepatocytes compared to those in rats. Hence, fxr(-/-) and fxr(+/+) mouse models were used to discriminate between VDR vs. FXR effects in murine livers. Hepatic Cyp7a1 in mice was found to be upregulated with 1,25(OH)2D3 treatment, via the derepression of the short heterodimer partner (SHP). Putative VDREs, identified in mouse and human SHP promoters, were responsible for the inhibitory effect on SHP. The increase in hepatic Cyp7a1 expression and decreased plasma and liver cholesterol were observed in mice prefed with a Western diet. A strong correlation was found between tissue Cyp7a1 and P-gp changes and 1,25(OH)2D3 plasma and tissue concentrations, confirming that VDR plays an important role in the disposition of xenobiotics and cholesterol metabolism. Moreover, renal and brain Mdr1a/P-gp were found to be directly upregulated by the VDR in mice, and concomitantly, increased renal and brain secretion of digoxin, a P-gp substrate, in vivo. The important observations: the cholesterol lowering and increased brain P-gp efflux activity properties suggest that VDR is a therapeutic target for treatment of hypercholesterolemia and Alzheimer’s diseases, since beta amyloid, precursors of plague, are P-gp substrates.

Keywords: Vitamin D Receptor (VDR)
transporters
enzymes
calcitriol or 1,25(OH)2D3
P-glycoprotein (P-gp)
cholesterol metabolizing enzyme
CYP7A1
short heterodimer partner (SHP)
farnesoid X receptor (FXR)
physiologically based pharmacokinetic (PBPK) model
multidrug resistance protein 1 (MDR1)
multidrug resistance assoicated protein (MRP)
bile acids
cholesterol
homeostasis
nuclear receptor
Advisor: Pang, K. Sandy
TRADD Mediates Inflammatory Responses in the Cytoplasm and Tumor Suppression in the Nucleus

TNF is a proinflammatory cytokine whose pleiotropic biological properties are signaled through the receptor TNFR1. Activation of this signaling pathway has been implicated in a broad range of biological functions, including host defense, inflammation, apoptosis, autoimmunity, and cancer. TRADD is an adaptor protein that is recruited to TNFR1 upon receptor engagement. Using a Tradd-deficient murine model, we demonstrated that TRADD is essential for both TNF-mediated apoptosis and inflammatory responses. In addition to refining the role of TRADD in TNFR1 signaling, we have also identified a novel function of TRADD in TLR3 and TLR4 pathways, which are key drivers of the innate immune response. We showed that TRADD is involved in NF-κB activation upon TLR3 and TLR4 stimulation, and Tradd-deficient macrophages showed impaired inflammatory cytokine production in response to TLR ligands in vitro. These data reveal the multifaceted functions of TRADD in immune signaling pathways. Beyond its role in the immune response, TNF has also been shown to play a crucial, cell-non-autonomous role in driving tumor growth in various models of cancer. We initially sought to determine whether TRADD is essential for this aspect of TNF function by employing the use of a chemical induced skin carcinogenesis model in which the tumor-promoting role of TNF is very well established. In this model, H-Ras is the major driving oncogene. We found that Tradd deficiency accelerated tumor formation in mouse skin, in strong contrast to what was observed in Tnfr1-deficient mice. Further in vitro analyses revealed that upon expression of oncogenic H-Ras, Tradd-deficient murine fibroblasts displayed both reduced cell cycle arrest and repression of Ras induced cellular senescence. Importantly, the level of p19Arf induced by H-Ras expression was reduced in Tradd-deficient fibroblasts in a post-translational manner. Our biochemical evidence suggests that TRADD can shuttle dynamically between the cytoplasm and the nucleus; in doing so, nuclear TRADD interacts with ULF, a newly identified E3 ubiquitin ligase for p19Arf. Interaction between nuclear TRADD and ULF sequesters ULF away from p19Arf, leading to p19Arf stabilization and tumor suppression. Together, these data demonstrate the functional diversity of TRADD in different compartments of the cell.

Keywords: Inflammation
Cancer
Advisor: Mak, Tak Wah
Mechanisms Controlling the Distribution of Two Invasive Bromus Species

In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two of the most aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. While Bromus tectorum is dominant in the “cold desert” steppes of the Intermountain region of western North America, B. rubens is one of the severe grass invaders in the “hot deserts” of southwestern North America. I first evaluated whether winter freezing tolerance is the mechanism responsible for the distinct northern range limits of Bromus species. Bromus rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn reductions in temperature below -12°C, Bromus tectorum, by contrast, cold hardens rapidly and is not impacted by the sudden severe late-autumn cold. Photosynthetic response to temperature does not explain their current range separation. Bromus species differ little in their photosynthetic temperature responses and the acclimation pattern of photosynthesis. Both species acclimated to a broad range of temperature through the amelioration of Pi regeneration limitation at sub-optimal temperatures and improved carboxylation capacity above the thermal optimum which probably resulted from increased thermostability of Rubisco activase. The effect of elevated temperatures during flowering on the seed yield of Bromus species demonstrates that neither species produces seed at 36°C and above. These thresholds are close to temperatures encountered during flowering in their natural environment. In summary, climatic changes will cause northward range expansion of Bromus species due to less severe autumn and winter, while reproductive failure could cause range contraction at their southern margins.

Keywords: species distribution
invasive species
plant physiology and reproduction
temperature
tolerance limits
photosynthesis
Advisor: Sage, Rowan F.
A Novel Lipid-based Nanotechnology Platform For Biomedical Imaging And Breast Cancer Chemotherapy

A novel, lipid-based platform nanotechnology has been designed to overcome limitations of in vivo fluorescent imaging, multidrug resistance (MDR) phenotypes hindering breast cancer chemotherapy, and shortcomings of magnetic resonance imaging (MRI) thermometry. Using this platform, three nanoparticle systems have been developed: QD-SLN (quantum dot-loaded solid lipid nanoparticles), DMsPLN (doxorubicin and mitomycin C co-loaded polymer-lipid hybrid nanoparticles), and HLN (hydrogel-lipid hybrid nanoparticles). Stealth, near-infrared emitting QD-SLN were developed for deep tissue fluorescence imaging, which were capable of extending the depth of penetration beyond 2 cm, with near complete probe clearance and good tolerability in vivo. The QD-SLN was used to evaluate the biodistribution of non-targeted SLN and actively targeted RGD-conjugated SLN. Non-targeted SLN accumulated in breast tumors and evaded liver uptake. The RGD-SLN showed prolonged retention in breast tumor neovasculature at the cost of lesser tumor accumulation due to enhanced liver uptake. With this information, a long circulating, non-targeted DMsPLN with a synergistic cancer chemotherapeutic combination of doxorubicin and mitomycin C was formulated to overcome MDR, enhancing breast cancer chemotherapy. Extensive tumor cell uptake and perinuclear trafficking of DMsPLN overcame the MDR phenotype of breast tumor cells in vitro. The DMsPLN provided the most efficacious chemotherapy reported in literature against aggressive mouse mammary tumors in vivo with significant reduction in whole animal and cardiotoxicity as compared to clinically applied liposomal doxorubicin. In establishing our tumor models, the impact of Matrigel™ on the tumor microenvironment was investigated, demonstrating altered tumor vascular and lymphatic anatomy and physiology, and significantly impacting nanomedicines assessment in mouse models of cancer. In all in vivo studies, tumors were established without use of Matrigel™. To guide thermotherapy of solid tumors, a novel HLN was formulated for use in MRI thermometry, presenting the first contrast agent capable of indicating a tunable, absolute two-point temperature window. In using specific limitations of therapeutic and imaging modalities to inform rational nanoparticle design, this lipid-based platform nanotechnology has extended the application of fluorescence imaging in vivo, enhanced the utility of nanoparticulate chemotherapeutics against breast cancer independent of MDR status, and provided novel functionality for MRI thermometry.

Keywords: Nanotechnology
Breast Cancer
Multidrug Resistance
MRI Thermometry
In Vivo Fluorescence Imaging
Integrin Receptor Targeting
Advisor: Wu, Xiao Yu
Role of Hypoxia-inducible Factor in Kidney Cancer

Cellular adaptation to conditions of stress is critical to the survival of all organisms. In mammalian cells, reduced oxygen availability, or hypoxia, triggers a myriad of alterations within molecular pathways aimed at ensuring sustained viability and functionality of vital organs. The master regulator of the hypoxic response is the heterodimeric HIF transcription factor, composed of an oxygen-labile HIFalpha subunit and a constitutively expressed and stable HIFbeta(ARNT) subunit. While experiments in mice have demonstrated the indispensability of HIF1alpha/HIF2alpha, unchecked hyperactivation of HIF is associated with pathological complications, such as the development of clear-cell renal cell carcinoma (ccRCC), the most common form of kidney cancer. In particular, overexpression of HIF2alpha has been intimately linked to ccRCC molecular pathogenesis. Here, we report that HIF2alpha overexpression leads to Akt-mediated hyperactivation of Hdm2, resulting in decreased activity of p53 and increased resistance to apoptosis. Significantly, we show that restoration of p53 activity via inhibition of Hdm2 reverses chemoresistance of otherwise refractory ccRCC cells. We also demonstrate that the picornavirus EMCV (Encephalomyocarditis virus) efficiently destroys ccRCC tumour cells in an NF-kappaB- and HIFalpha-dependent manner both in vitro and in a mouse xenograft model. This work provides pre-clinical evidence for the potential use of EMCV in an oncolytic virus-based approach to the treatment of advanced ccRCC. In addition, using a cell biology-based approach we reveal that inhibition of the DNA methyltransferase DNMT1 leads to enhanced HIF promoter-binding affinity and transactivation activity in a manner that is independent of changes in HIFalpha protein levels. This study uncovers a novel HIF regulatory mechanism in mammalian cells. In summary, the work presented here provides insight into the molecular mechanisms governing HIF activity and the effects of HIF on the molecular pathogenesis of ccRCC. Our findings have the potential to provide new therapeutic avenues for the treatment of kidney cancer.

Keywords: Kidney Cancer
Hypoxia-inducible Factor
Advisor: Ohh, Michael
Plants and Peoples: French and Indigenous Botanical Knowledges in Colonial North America, 1600 – 1760

As North American plants took root in Parisian botanical gardens and regularly appeared in scientific texts in the seventeenth and eighteenth centuries, they retained their connections to networks of ecological and cultural exchange in colonial North America. In this dissertation I study the history of French botany and natural history as it became an Atlantic enterprise during this time, analyzing the production of knowledge about North American flora and the place of this knowledge in larger processes of colonialism and imperial expansion in the French Atlantic World. I focus particular attention on recovering the role of aboriginal peoples in the production of knowledge about colonial environments on both sides of the Atlantic. Rather than integrating aboriginal collectors, chefs and healers into traditional histories of western science, I integrate familiar histories of science into larger histories of cultural contact in an Atlantic World with multiple centres of knowledge production and exchange. This dissertation develops two closely related arguments. First, I argue that French encounters with American environments and Native cultures were inseparable. Jesuit missionaries, for example, called both a plant and a native culture “wild rice,” conflating descriptions of local ecological and morphological features of the Great Lakes plant with accounts of indigenous cultural and moral attributes. Second, “Plants and Peoples” also analyzes the process by which the Paris-based Académie Royale des Sciences expanded its reach into North America and argues that French colonial naturalists drew on a vibrant conversation between diverse colonial and indigenous communities. Yet indigenous participation and the knowledges they provided were progressively effaced over the course of the seventeenth and eighteenth centuries. This research therefore presents both a new understanding of the history of early modern and enlightenment botany and a lens through which to revisit and enrich familiar histories of cultural exchange in colonial North America.

Keywords: Environment
Botany
Colonialism
Colonial Science
Indigenous Knowledge, Traditional Ecological Knowledge
Atlantic World
Jesuits
Natural History
New France
French North America
Advisor: Greer, Allan
The War on Autism: On Normative Violence and the Cultural Production of Autism Advocacy

This dissertation brings together a variety of interpretive theoretical perspectives born of the fields of disability studies, critical race theory, cultural studies and queer and feminist studies to analyze the social significance and productive effects of cultural representations of autism. Specifically, this work addresses contemporary enactments of autism advocacy as found in the mass media, education literature and policy as well as in fundraising campaigns. In response to a global/izing economy that privileges the fast, efficient exchange of information and knowledge, I attend to how autism appears in the field of autism advocacy as an abbreviation; its multiple meaning distilled down to a series of ‘red flags’ in awareness campaigns, bulleted ‘facts’ in information pamphlets, statistics in policy reports. I analyze the relationships between these fragmentary enactments of autism and trace their continuities so as to make legible an underlying logic: a powerful and ubiquitous logic that casts autism as a pathological threat to normative life, and advocacy as that which must eliminate this threat, thus, limiting the role of the ‘good’ autism advocate to one positioned ‘against’ autism. This dissertation shows how dominant, contemporary discourses of autism advocacy that narrate autism as some ‘thing’ to be ‘fought’, ‘combated’, or ‘warred against’ function to shape ‘life’ as conditional and cast autism as (one of) its condition(s). As autism is discursively and ideologically made separate from the vital category of life itself, and as bodies and minds of living people are relentlessly divided up into vital and non-vital parts, individual and collective life ‘with’ (the condition of) autism becomes life that is conceptualized as ‘almost living’ or ‘mostly dead’. I demonstrate how such an understanding of the conditionality of life is a necessary pre-condition for normative acts of violence – violence enacted in the name of securing the norm and violence that is normalized as necessary.

Keywords: autism
advocacy
biopolitics
disability studies
critical race theory
violence
normativity
war
governmentality
representation
Advisor: Titchkosky, Tanya