Cell and Developmental Biology Commons^™

A Bioinformatics Approach To Understanding The Pathogenesis Of Ectopic Spine Calcification, Fang Chi Wang

Electronic Thesis and Dissertation Repository

This study used mice lacking equilibrative nucleoside transporter 1 (ENT1^-/-) as a preclinical model to study pathogenesis of ectopic spine mineralization in diffuse idiopathic skeletal hyperostosis (DISH). We hypothesized that mineralization of the annulus fibrosus (AF), was driven by dysregulation of cellular processes and pathways associated with apoptosis, S100A9 proteins, the PI3K-Akt pathway, and lipid metabolism. Target pathways and processes were assessed using in situ localization and quantitative analyses. Metabolomic analysis of AF and plasma data was conducted to identify altered metabolites. Results demonstrate increased caspase-3 activity in the AF of ENT1^-/- mice at both timepoints …

The Adaptor Protein P66shc Governs Central Nervous System Cell Metabolism And Resistance To Aβ Toxicity, Asad Lone

Electronic Thesis and Dissertation Repository

Alzheimer’s disease (AD), a progressive and irreversible neurodegenerative disorder, and is the leading cause of dementia worldwide. It has been posited that AD is caused by the gradual deposition of toxic amyloid-b (Ab) plaques in the brain- that cause oxidative stress and eventually leads to neuronal death and synaptic loss. However, multiple therapies that either interfere with the production, or enhance the removal of Ab from the brain, have ultimately failed to slow or prevent AD. With the ever-increasing burden of AD worldwide, there exists an urgent need for novel therapeutic targets. The adult human brain is an energy demanding …

Extrinsic And Intrinsic Factors Influencing Homeostasis And Repair In Oral Tissues, Georgia Nikoloudaki

Electronic Thesis and Dissertation Repository

The oral tissues, including gingiva and buccal mucosa, heal rapidly with minimal scar formation. Although in the oral cavity, the palatal mucosa is associated with excessive scarring in response to injury. In this thesis, first, I investigated the complex relationship between cells and their microenvironment using wound healing models in which extracellular matrix composition and mechanical stiffness affect cellular responses during acute wound repair. I also determined how intrinsic differences of cells recruited during healing contribute to wound resolution.

In Chapter 2, I first investigated cell-extrinsic factors, specifically the influence of the pro-fibrotic matricellular protein periostin on palatal healing. Using …

The Role Of Reactive Oxygen Species In The Accumulation Of Driver Mutations In B Cell Acute Lymphoblastic Leukemia, Mia P. Sams

Electronic Thesis and Dissertation Repository

B cell acute lymphoblastic leukemia (B-ALL) is the most prevalent type of cancer in young children and is associated with recurrent mutations and high levels of reactive oxygen species (ROS). The antioxidant N-acetylcysteine was tested for its ability to prolong lifespan of a mouse model of B-ALL and reduce frequency of mutations. Mice treated with 1g/L of N-acetylcysteine in drinking water were found to have delayed onset of B-ALL at 11 weeks of age and changes in gene expression relating to B cell development, calcium-apoptosis signaling, and pathways in cancer, although no differences in lifespan were observed. Tumours from treated …

Connexin 43 Contributes To Phenotypic Variability Of The Mouse Skull, Elizabeth Jewlal

Electronic Thesis and Dissertation Repository

The purpose of this study was to determine whether connexin 43 (Cx43) contributes to craniofacial phenotypic variability. Skull shape and variation were compared within and among two heterozygous mutant mouse models (G60S/+ and I130T/+) that exhibit different levels of Cx43 channel function when compared to their wildtype counterparts (~80% and ~50% reduction in function, respectively). Results indicated mutants have significant differences in skull shape compared to wildtype littermates. Similar patterns of shape difference were found in both mutants. Increased skull shape variation and a disruption in the covariation of skull structures were observed in G60S/+ mutants only. These results show …

Kindlin-1 Is Involved In Spreading, Migration, And Protein Regulation In Epidermal Scc-13 Cells, Naomi Mishan

Electronic Thesis and Dissertation Repository

Kindlin-1 is a scaffold protein linking the cytoskeleton to the extracellular matrix. Loss of function mutations in the FERMT1 gene (encoding Kindlin-1) cause gastrointestinal and skin defects associated with increased susceptibility to aggressive epidermal squamous cell carcinoma (SCC). This study investigated the consequences of targeted FERMT1 inactivation in the SCC-13 cell line of epidermal SCC. My studies demonstrate Kindlin-1 is not essential for SCC-13 proliferation or clonogenic potential in culture. Kindlin-1 was required for cell spreading on collagen I, but not on laminin-332, and its absence enhanced SCC-13 directional migration. Finally, I identified several proteins involved in tumor formation and …

Free Fatty Acid Treatment Alters Autophagy During Mouse Preimplantation Embryo Development, Zuleika C. L. Leung

Electronic Thesis and Dissertation Repository

Obesity-induced hyperlipidemia is one of the main factors for female infertility. Hyperlipidemia, specifically with high levels of palmitic acid (PA) and oleic acid (OA), interferes with preimplantation development. Autophagy is essential in early embryo development but, it is unknown whether hyperlipidemia affects autophagic mechanisms in preimplantation embryos. It was hypothesized that PA will alter autophagy in preimplantation mouse embryos and that the subsequent effects will be reversed by OA. PA impaired blastocyst development by arresting embryos at the 8-cell stage. PA also elevated early embryo autophagy by increasing autophagosome formation, decreasing maturation, and disrupting degradation. Co-treatment with OA showed developmental …

The Regulation Of Pannexin1 And Pannexin2 In The Skin In Health And Disease, Rafael E. Sanchez Pupo

Electronic Thesis and Dissertation Repository

Pannexins (PANX1, 2, 3) are a family of channel-forming glycoproteins that mediate intracellular and paracrine signaling. In contrast to PANX2, PANX1 has been extensively investigated in the skin, modulating cell differentiation, wound healing, and melanoma development. PANX1 and PANX2 can co-exist in the same cell and form mixed channels where their glycosylation seems to regulate their intermixing. N-glycosylation and caspase cleavage have been proposed as modulators of the function of PANX1, but their effects on PANX2 are unknown. We explored the PANX2 expression in mouse skin and showed that a Panx2 splice variant (PANX2-202) is continuously expressed throughout aging skin. …

Maternal Lifelong Western Diet Consumption Impacts Placental And Brain Development In The Term Guinea Pig Fetus, Carlene H. Cihosky

Electronic Thesis and Dissertation Repository

Both metabolic and cognitive dysfunction can originate from fetal reprogramming precipitating from adverse conditions experienced in utero. Of note is the western diet (WD), which is associated with maternal energy imbalances that may hinder fetal development through altered placental function. Brain-derived neurotrophic factor (BDNF), a growth factor that supports the placenta and developing brain, is responsive to such energy imbalances. This study sought to investigate the impact of lifelong maternal WD consumption on fetoplacental development, focusing on relations between placental changes, and fetal growth and neurodevelopment in a guinea pig model. Maternal WD consumption resulting in a lean metabolically …

Functional Role Of Dream And Dyrk1a In High-Grade Serous Ovarian Cancer Cell Dormancy, Pirunthan Perampalam

Electronic Thesis and Dissertation Repository

High-grade serous ovarian cancer (HGSOC) is the most common form of ovarian cancer. The majority of women are disproportionately diagnosed at an advanced stage (stage III-IV) of the disease when tumours have progressed beyond the ovaries or fallopian tubes and into the peritoneal cavity. Survival rates at late-stage are as low as 25% and chemoresistant disease recurrence is common, affecting up to 90% of patients. Multicellular clusters called spheroids contribute to dormancy, chemoresistance, and metastases and are a major challenge to treatment of HGSOC. Spheroid cells undergo reversible quiescence to evade chemotherapy in a process mediated by the mammalian DREAM …

The Effects Of Maternal Delta-9-Tetrahydrocannabinol And Cannabidiol Exposure On Fetal Heart Development In Mice, Gregory Robinson

Electronic Thesis and Dissertation Repository

Up to 22.6% of pregnant women consume cannabis during pregnancy despite the uncertainty of teratogenicity of the main ingredients in cannabis, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). This study tested the hypothesis that gestational THC and CBD exposure leads to heart abnormalities. Daily, oral THC exposure induced heart abnormalities in 68% of offspring with three main phenotypes including thickened semilunar valves, ventricular myocardial hypertrophy and hypoplastic coronary arteries in fetuses, and postnatal cardiac dysfunction. Altered gene expression of key cardiogenic regulators, increased proliferation, and reduced epicardial epithelial-to-mesenchymal-transition were demonstrated implicating potential mechanisms responsible for these abnormalities. Also, maternal CBD exposure resulted …

Pan-Cancer Analysis Of Telomerase Reverse Transcriptase (Tert) Isoforms, Mathushan Subasri

Electronic Thesis and Dissertation Repository

Reactivation of the multi-subunit ribonucleoprotein telomerase is the primary telomere maintenance mechanism in cancer, but it is rate-limited by the enzymatic component, telomerase reverse transcriptase (TERT). While regulatory in nature, TERT alternative splice variant/isoform regulation and functions are not fully elucidated and are further complicated by their highly diverse expression. In this thesis, I characterized TERT expression across normal and neoplastic tissues using TCGA and GTEx RNA-sequencing data. In doing so, I demonstrated the global overexpression and splicing shift towards full-length TERT in neoplastic tissue. Furthermore, my studies identified tumour subtype expression differences possibly regulated by subtype-specific characteristics, detailed heterogeneity …

Effect Of N-Acetyl-L-Cysteine Prevention Or Intervention On Diet Induced Beta Cell Compensation And Dysfunction, Madison Wallace

Electronic Thesis and Dissertation Repository

Type 2 diabetes mellitus (T2DM) progression increases oxidative stress which contributes to beta cell compensation and eventual dysfunction. To investigate the role of antioxidant N-acetyl-L-cysteine (NAC) on beta cell function and pancreatic stellate cell activation (aSMA⁺) during early and late stages of compensation, NAC was used for preventative (p) and intervention (i) treatments in C57BL/6N mice fed a 60% kcal high-fat diet (HFD) for 8 or 22 weeks. Significantly improved glucose tolerance was observed at 22 weeks following pNAC treatment in HFD mice. Although 22-week HFD mice displayed hyperinsulinemia, beta cell hypertrophy, decreased beta cell PDX-1 nuclear localization, …

Pregestational Diabetes Induced Congenital Heart Defects And Coronary Artery Malformations; Mechanisms And Preventative Therapies, Anish Engineer

Electronic Thesis and Dissertation Repository

Congenital heart defects (CHDs) arise from perturbations in complex molecular and cellular processes underlying normal embryonic heart development. CHDs are the most common congenital malformation, occurring in 1 to 5% of live births, and are the leading cause of pediatric mortality. Adverse genetic and environmental factors can impede normal cardiogenesis and increase the likelihood of CHDs. Pregestational maternal diabetes increases the risk of CHDs in children by more than four-fold. As the prevalence of diabetes rapidly rises among women of childbearing age, there is a need to investigate the mechanisms and potential preventative strategies for these defects. The aim of …

Maternal Nicotine Exposure Induces Congenital Heart Defects In The Offspring Of Mice, Elizabeth Greco

Electronic Thesis and Dissertation Repository

Congenital heart defects are the most prevalent birth defect, and maternal cigarette smoking is a known risk factor. Nicotine replacement therapies are recommended to pregnant women who smoke to aid in smoking cessation, as this alternative is thought to be much safer compared to cigarette smoking. However, these products contain nicotine, and the safety of nicotine on the developing heart is not well known. In this thesis, a mouse model was used to test the hypothesis that maternal nicotine exposure (MNE) during pregnancy leads to congenital heart defects and coronary artery defects in the offspring of mice. MNE resulted in …

The Mitochondrial Calcium Uniporter Regulator 1 (Mcur1) Matrix Domain Is A Self-Associated Multimer Sensitive To Divalent Cations, Naveed Siddiqui

Electronic Thesis and Dissertation Repository

Mitochondria are primarily appreciated for the generation of adenosine triphosphate (ATP), a chemical store of energy required by all cells. These organelles, however, also play key roles in apoptosis, autophagy and shaping cytosolic calcium (Ca²⁺) signaling via Ca²⁺ uptake into the mitochondrial matrix. This Ca²⁺ uptake is mediated chiefly via the mitochondrial Ca²⁺ uniporter (MCU), an inner mitochondrial membrane protein that oligomerizes to form a Ca²⁺ selective pore. MCU is regulated by several protein binding partners, including the recently identified MCU regulator-1 (MCUR1). MCUR1 stabilizes a higher order MCU heterocomplex through interactions with MCU …

Effects Of Maternal Protein Restriction On The Pulmonary Surfactant System During The Early Life And Adulthood, Reza Khazaee

Electronic Thesis and Dissertation Repository

Fetal growth restriction (FGR) is defined by low birth weight and contributes to a variety of adult-onset diseases with different severities between males and females. However, the effects of FGR on the pulmonary surfactant are not fully elucidated. In this thesis, first, we investigated the FGR effects on the lung function and the surfactant system at the early postnatal life. It was hypothesized that FGR contributes to alterations of lung mechanics and the surfactant system during the neonatal period. Second, we assessed the FGR effects on the surfactant system in response to sepsis in adulthood. It was hypothesized that FGR …

Lung-Derived Selectins Interact With Cd44 And Enhance The Migration Of Breast Cancer Cells, Sami U. Khan

Electronic Thesis and Dissertation Repository

The lung is among the deadliest sites of breast cancer metastasis. Previous work from our laboratory demonstrated that aggressive CD44-expressing breast cancer cells preferentially metastasize to the lung in vivo, and observed the presence of multiple CD44-interacting proteins in the lung including E-, L- and P-selectin. We hypothesized that lung-derived selectins promote breast cancer migration and/or growth via interactions with CD44. Using an ex vivo model of the soluble lung-microenvironment, we demonstrate that lung-derived selectins enhance in vitro migration but not proliferation of breast cancer cells. Co-immunoprecipitation experiments reveal that CD44 expressed by breast cancer cells in vitro interacts …

Examining The Tissue-Level And Gross Phenotypic Effects Of The Connexin43i130t/+ Mutation On The Developing Mouse Skull, Sommer G.E. Jarvis

Electronic Thesis and Dissertation Repository

The purpose of this study was to investigate the effects of reduced Connexin43 function on the developing skull phenotype, osteoblast and chondrocyte proliferation and differentiation, and to determine if a correlation exists between cell processes and gross morphology. Using the Cx43^I130T/+mouse model, skull shape was analyzed using geometric morphometrics and cell proliferation and differentiation were assessed using immunohistochemistry at late embryonic and early post-natal stages. The largest shape changes between Cx43^I130T/+ and wildtype mice were observed in the cranial base and facial skeleton. Changes infacial morphology correspond to reduced osteoblast differentiation. However, no changes in chondrocyte proliferation …

Functional Changes Associated With Shroom3 Deficiency And Mutation: Implications In Renal Pathophysiology And Disease, Doyun Ko

Electronic Thesis and Dissertation Repository

Chronic kidney disease (CKD) is a substantial global health burden that has recently been linked to the genetic locus SHROOM3 by several genome-wide association studies. Shroom3 is an actin-binding protein that is necessary for inducing apical constriction in epithelial cells. Our lab has previously shown that Shroom3 is critical for proper kidney development and loss of Shroom3 produces symptoms associated with CKD. As hypertension is both a leading cause and comorbidity of CKD, I hypothesized that loss of Shroom3 confers increased susceptibility to hypertension. Using a high-salt induced model of hypertension, I show that Shroom3 deficient mice do not become …

Contribution Of Activating Transcription Factor 3 To Development Of Acinar-To-Ductal Cell Metaplasia, Jelena Toma

Electronic Thesis and Dissertation Repository

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in North America. The highest risk factor for PDAC is recurrent pancreatitis. While the link between PDAC and pancreatitis is unknown, de-differentiation of acinar cells is common to both diseases. Our lab has shown that Activating Transcription Factor 3 (ATF3), a factor upregulated during pancreatic injury, contributes to the development of acinar-to-ductal cell metaplasia (ADM), a precursor phenotype of PDAC. The goal of this study was to identify how ATF3 contributes to ADM. I hypothesize that ATF3 regulates acinar gene expression promoting ADM. We observed decreased ADM development …

Functional Characteristics Of Four Novel Lone Atrial Fibrillation-Linked Connexin40 Mutants, Mahmoud Noureldin

Electronic Thesis and Dissertation Repository

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. Recently, four novel heterozygous Cx40 mutations, K107R, L223M, Q236H, and I257L were identified in 4 of 310 unrelated AF patients. To study possible alterations associated with these mutants, we studied their localization and function using gap junction (GJ)-deficient model cells. Cell pairs expressing Q236H alone or together with wildtype Cx43 showed a significantly lower coupling conductance. Impaired GJ function and dominant negative action on Cx43 of this mutant are consistent with previous findings on the majority of AF-linked Cx40 mutants. The remaining three novel AF-linked mutants did not show …

Cerebral Lactate Metabolism And Memory: Implications For Alzheimer's Disease, Richard Andrew Harris

Electronic Thesis and Dissertation Repository

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by amyloid plaques that are comprised of aggregated amyloid-beta peptides. These toxic proteins promote mitochondrial dysfunction and neuronal cell death. A shift in metabolism away from oxidative phosphorylation and toward aerobic glycolysis, with the concomitant production of lactate, affords neurons a survival advantage against amyloid-beta toxicity. Recent evidence now suggests that aerobic glycolysis in the brain plays a critical role in supporting synaptic plasticity, learning, and memory. However, the role of aerobic glycolysis and lactate metabolism in AD-mediated cognitive decline is unknown. My objective was to test the hypotheses that aerobic glycolysis …

The Effects Of Acetylenic Tricyclic Bis-(Cyano Enone) On Cell Migration, Eddie Chan

Electronic Thesis and Dissertation Repository

Although cancer survival rates have significantly improved over the past few decades, the improvements are primarily due to early diagnosis and inhibiting cancer growth. Limited progress has been made in the treatment of cancer metastasis, which contributes to 90% of cancer related deaths, and therapeutic agents targeting the various aspects of metastasis are lacking. One potential approach is to utilize small pharmacological compounds to inhibit tumour cell motility, as a strategy against tumour cell migration, invasion, and metastasis. The acetylenic tricyclic bis-(cyano enone), TBE-31, has been shown to be a promising chemopreventative compound. However, its effects on cell migration are …

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 …

Discovery Of Novel Diagnostic Biomarkers On Prostate Tumor Microparticles For Discriminating Between Low And High Risk Prostate Cancer And Improving Prostate Cancer Screening, Sabine Brett

Electronic Thesis and Dissertation Repository

There are few protein-based biomarkers to accurately distinguish between patients with low risk prostate cancer from those with high risk disease in a non-invasive manner. Prostate specific antigen (PSA) is used for clinical follow-up of prostate cancer; however, it is not effective as a screening tool. As a result, many men with non-life threatening disease having to undergo unnecessary and painful biopsies. Therefore, there is a dire need for minimally invasive platforms for monitoring patients with clinically significant prostate cancer. Prostate cell microparticles (PCMPs) released by prostate epithelial cells into plasma are a potential source of biomarkers specific for prostate …

Cal And Magi Pdz Protein Regulation Of Crfr1 And 5-Ht2ar Trafficking And Signaling, Maha Mahmoud Hammad

Electronic Thesis and Dissertation Repository

PDZ (PSD95/Disc Large/Zona Occludens) domain-containing proteins are scaffolding proteins that play important roles in regulating the activity of G protein-coupled receptors. Corticotropin Releasing Factor Receptor 1 (CRFR1) and Serotonin 2A Receptor (5-HT_2AR) are two GPCRs that are commonly associated with mental disorders. Both receptors also contain a class I PDZ-binding motif at the carboxyl terminal tail. In the first chapter, we investigate the effects of CAL (CFTR-associated ligand) on regulating the trafficking and signaling of CRFR1. We demonstrate a role for CAL in inhibiting CRFR1 endocytosis, cell surface expression, and CRF-mediated ERK1/2 signaling via the CRFR1 PDZ-binding motif. …

Panx1 And Panx3 Regulate Adipocyte Development And Fat Accumulation In Vivo, Vanessa R. Lee

Electronic Thesis and Dissertation Repository

The obesity epidemic is a growing concern due to its various comorbidities and associated risk factors. Pannexins 1 and 3 (Panx1 and Panx3), are members of a family of channel-forming glycoproteins that have been reported to be important in paracrine signaling and development. Panx1 and Panx3 are homologous and are regulated in many different cell types, mediating cell proliferation and differentiation. We have shown that Panx1 and Panx3 are expressed in adipocytes and adipose-derived stromal cells (ASCs) throughout the process of differentiation. Mice globally lacking Panx1 (Panx1 KO) have significantly greater total fat mass compared to wildtype (WT) mice under …

Oncolytic Virus Therapy For The Treatment Of Metastatic Ovarian Cancer, Jessica Tong

Electronic Thesis and Dissertation Repository

The management of patients with epithelial ovarian cancer (EOC) faces two major challenges which standard treatments fail to effectively address: 1) Diffuse metastasis as a consequence of late stage diagnosis and 2) intra-tumoral heterogeneity, which fuels tumor evolution and drives the acquisition of chemotherapeutic resistance. In this thesis, we tested new therapeutic strategies using a 3-dimensional in vitro spheroid culture model that mimics key steps of epithelial ovarian cancer metastasis; and another model that mimics both temporal and cellular heterogeneity by establishing multiple cell lines from a single patient over the course of disease progression. Using these models, we investigated …

The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya

Electronic Thesis and Dissertation Repository

Bone development and repair involve complex processes that include interaction between cells and their surrounding matrix. In the body, bone sialoprotein (BSP) expression is up-regulated at the onset of mineralization. BSP is a multifunctional acidic phosphoprotein with collagen-binding, hydroxyapatite nucleating, and integrin recognition (RGD sequence, which is important for cell-attachment and signaling) regions. Mice lacking BSP expression (Bsp^-/-), exhibit a bone phenotype with reductions in bone mineral density, bone length, osteoclast activation, and impaired bone healing. This thesis examined the role of BSP in tooth development and also its potential use as a therapeutic reagent for bone …