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Effects Of High Glucose On Autophagy And Apoptosis In Preimplantation Mouse Embryo Culture, Virginia Wolfe

Electronic Thesis and Dissertation Repository

Maternal diabetes increases congenital malformations due to teratogenic effects of glucose on the developing embryo. High glucose culture alters preimplantation embryo development and is associated with increased oxidative stress. Apoptosis and autophagy are programmed cell death and survival mechanisms induced by oxidative stress, but their role in preimplantation diabetic embryopathy is poorly elucidated. It was hypothesized that high glucose culture would alter autophagic and apoptotic responses, and that they are dependent on the timing of high glucose culture initiation. Embryos were cultured with 0.2 mM (control) or 25 mM (high glucose) of D-glucose starting from the early (36 hpi) or …

Characterization Of The Principal And Secondary Islets During Pancreatic Development In Zebrafish With A Crispr-Mediated Glis3 Knockout, Caleb Harsin

Honors College Theses

The Krüppel-like transcription factor, Gli-similar 3 (Glis3) has been implicated in several human pathologies including neonatal diabetes, congenital hypothyroidism, and polycystic kidney disease. Numerous genome-wide association studies (GWAS) have additionally identified Glis3 as a risk locus for the development of both type 1 and type 2 diabetes mellitus. Our previous data suggest possible roles for Glis3 in endocrine pancreas specification in mice, but despite its clinical significance, much remains unknown about the role(s) Glis3 plays during development. To elucidate Glis3 gene function, a CRISPR-mediated knockout line of zebrafish was developed by deleting a segment of the Glis3 coding region …

Tgif1 Physiological Levels Limit Β-Cell Distress And Neonatal Diabetes, Creighton J. Friend

Theses and Dissertations

TGIF1 belongs to the superfamily of homeodomain proteins, which regulate a wide variety of biological functions, including cell stemness and specification of cell fate during early development. Perhaps surprisingly, we found that enforced expression in pancreatic progenitor cells during embryogenesis resulted in severe diabetes, hinting at the possibility that TGIF1 might regulate pancreas development. Subsequent genetic experiments targeting β-cells showed that TGIF1 affected β-cell function and homeostasis. Transcriptomic analysis revealed that TGIF1 expression inhibits the expression of essential components of UPR signaling, underscoring a potential mechanism in which TGIF1 disrupts protein folding and secretion. Congruently, TGIF1 expression led to a …

Tracing The Fate Of Cytokeratin 19+ Cells During Beta Cell Regeneration Stimulated By Multipotent Stromal Cell-Secreted Effectors, Nazihah Rasiwala

Electronic Thesis and Dissertation Repository

Human bone marrow-derived multipotent stromal cells expanded under Wnt pathway stimulation secrete beta cell-regenerative factors collected as conditioned media (Wnt+ CdM). We used the cytokeratin 19 (CK19)-CreERT Rosa26-mTomato lineage tracing mouse to observe CK19+ cell conversion to insulin+ beta cells following intra-pancreatic injection of Wnt+ CdM. Tamoxifen treatment in mice induced labelling of CK19+ ductal and acinar cells with tdTomato and streptozotocin (50 mg/kg/day x 5 days) induced hyperglycemia. Injection of Wnt+ CdM preserved beta cell mass, reduced non-fasted blood glucose levels, and improved glucose tolerance over a 28-day period compared to controls. Insulin+/tdTomato+ cells in mice given Wnt+ CdM …

Determining The Role Of Mir-133a In The Diabetic Heart, Tyler Kambis

Theses & Dissertations

Diabetes mellitus (DM) is characterized by hyperglycemia, hyperlipidemia, and hypoinsulemia, each of which disrupt intracellular mechanisms in the heart. DM is a chronic metabolic disease delineated into two categories: insulin deficient-type 1 DM and insulin resistant-type 2 DM. Although they differ in underlying genetic and physiological factors, both significantly increase the risk of heart failure. Impaired insulin signaling shifts energy dependency from glycolysis towards fatty acid β-oxidation in the DM heart. This DM-induced metabolic shift increases mitochondrial stress leading to mitochondrial dysfunction and cell death in the heart. The metabolically entwined ferroptosis is a novel form of myocardial cell death …

Understanding The Effects Of Embryonic Hyperglycemia On Retinal Development And Maintenance, Kayla Titialii-Torres

Theses and Dissertations--Biology

Hundreds of millions of people are affected by diabetes worldwide. Whether they are diagnosed with prediabetes or Type I or II diabetes, there are a variety of mechanisms in the pathogenesis of diabetes. Diabetes is a disease which consists of recurring states of hyperglycemia that can be difficult to manage due to either lack of insulin production or improper utilization of insulin. While these mechanisms of action differ, complications induced by diabetes occur in both poorly regulated Type I and II. Common complications of diabetes include nerve damage, kidney damage, and eye damage. Eye damage specifically is called diabetic retinopathy …

Exploring Β-Cell Function And Heterogeneity In Obese Sm/J Mice, Mario Alejandro Miranda

Arts & Sciences Electronic Theses and Dissertations

Pancreatic β-cells perform glucose-stimulated insulin secretion, a process required to maintain systemic glucose homeostasis. Obesity promotes glycemic and inflammatory stress, causing β-cell death and dysfunction, resulting in diabetes. Efforts to improve β-cell function in obesity have been hampered by observations that β-cells are highly heterogeneous, varying in morphology, function, and gene expression. There is great need to understand the breadth of β-cell heterogeneity in health and obesity to improve diabetic therapies.High fat-fed SM/J mice spontaneously transition from hyperglycemic-obese to normoglycemic-obese with age, providing a unique opportunity to study β-cell adaptation. Here, we show that as they resolve hyperglycemia, obese SM/J …

Investigating The Differentiation And Functional Maturation Of Stem Cell-Derived Β Cells, Leonardo Velazco-Cruz

Arts & Sciences Electronic Theses and Dissertations

Diabetes mellitus is a chronic and global disease rapidly growing in prevalence. Diabetes can be characterized by the dysfunction or death of the glucose sensing insulin secreting  cell.  cells are located within the islet of Langerhans (islet), a tissue within the pancreas. Human islets are critical for the study and treatment of diabetes. However, they can only be obtained from cadaveric organ donors. These cadaveric islets do not proliferate and can only be maintained in vitro for short periods of time, making their availability rare and fleeting. Stem cell-derived -like cells can be generated in indefinite amounts and …

The Impact Of Age/Rage Signaling On Oxidative Stress Under Diabetic Conditions In Cardiac Fibroblasts, Christopher Dorroh

Honors Theses

Diabetes is a major health concern in the United States, with 1.5 million new cases diagnosed each year. Patients who suffer from diabetes have an increased risk of developing heart failure, a form of cardiovascular disease. Heart failure has been shown to result from increased left ventricular stiffness, which in turn is caused by increased remodeling of the extracellular matrix (ECM). This increase in ECM remodeling is a result of AGE/RAGE signaling, which occurs at a heightened level in the cardiac fibroblast cells of diabetics. Studies have shown that diabetics have elevated levels of AGEs (Advanced Glycation End-Products), which bind …

Insights Into The Therapeutic Potential Of Salt Inducible Kinase 1: A Novel Mechanism Of Metabolic Control, Randi Fitzgibbon

Dissertations & Theses (Open Access)

Salt inducible kinase 1 (SIK1) has been considered a stress-inducible kinase since it was first cloned in 1999. Continued efforts since this time have been dedicated to characterizing the structure and function of SIK1. Such research has laid the ground work for our understanding of SIK1 action and regulation in tissue and stimuli dependent manners. The fundamental findings of this dissertation continue in this tradition and include investigations of SIK1 regulatory mechanisms in skeletal muscle cells, the cellular and physiological effects of SIK1 loss of function in vitro and in vivo, and intracellular metabolic and mitochondrial regulation by this …

Characterization And Function Of Islet Antigen Presenting Cells During Nod Diabetes, Stephen Thomas Ferris

Arts & Sciences Electronic Theses and Dissertations

Here we characterized the initial antigen presenting cells (APCs) within the islet of Langerhans to ascertain their identity and functional role as it pertains to autoimmune diabetes. The activation of the adaptive immune system is induced by the innate immune system, and more specifically APCs. Therefore, it is crucial to identify the APCs that are initiating T1D in order to elucidate the break in tolerance and intervene in order to inhibit progression. We have found that there is a resident macrophage that is present in all strains of mice. This islet macrophage has a distinct transcriptional profile that is unique …

Effects Of Posttranslational Modification Of Transcription Factor Gli-Similar 3 By Sumoylation On Insulin Transcription In Pancreatic Β Cells, Tyler M. Hoard

Murray State Theses and Dissertations

The ability to control blood glucose levels is a fundamental component of vertebrates. In these organisms, blood glucose homeostasis is achieved through a fine-tuned mechanism that largely involves the secretion of hormones from the endocrine pancreas into the bloodstream. These hormones include glucagon, which is secreted by the α cells of the pancreas and initiates the release of glucose into the bloodstream through gluconeogenesis in the liver, and insulin, which is secreted from the β cells and signals the uptake of excess blood glucose by the peripheral tissue. Gli-similar 3 (Glis3) is a transcription factor that has previously been shown …

Characterization And Diurnal Measurement Of Oral Inflammation In Association With Glycemic Control, Periodontal Status, & Glucose Stimulation, Melanie N. Kuehl

USF Tampa Graduate Theses and Dissertations

Diabetes has afflicted 8.3%, approximately 25.8 million, of the United States population and is the seventh leading cause of death [1]. Type I diabetes (T1D) accounts for 5 to 10% of all diagnosed cases of diabetes in the United States [2]. If present trends continue, the rate of T1D incidence among children under the age of 14 will increase by 3% globally [3]. T1D is an autoimmune disorder in which the β-cells of the pancreatic islets are destroyed, leading to high blood sugar. Hyperglycemia and loss of immunological tolerance to self-antigens are common associations of T1D [4]. Periodontal disease impacts …

Characterization Of Ghrelin O-Acyltransferase Active Site, Leslie Patton

Honors Capstone Projects - All

Ghrelin, first discovered in 1999, is a 28-amino acid peptide hormone involved in the regulation of appetite, insulin secretion and sensitivity, and many neurological effects such as learning, memory, and depression.^1-6 Ghrelin has been identified to have a unique posttranslational octanoylation carried out by the enzyme ghrelin O-acyltransferase (GOAT). This distinctive modification is a point of interest in studying GOAT whereby blocking the acylation of the ghrelin could potentially halt the activity of the peptide hormone and provide a means of treating obesity, diabetes, and other diseases affected by ghrelin levels. The duration of my project involved working …

Diabetic Bone Marrow & Stem Cell Dysfunction, Meghan A. Piccinin

Electronic Thesis and Dissertation Repository

ii Abstract Abstract Defects in the proliferation, differentiation, and activity of bone marrow (BM)-derived vasculogenic/vascular stem cells (VSCs) have been observed in diabetes and contribute to the development of vascular complications. Diabetes leads to enhanced bone marrow adipogenesis, altering the composition of the BM stem cell (SC) niche and potentially disrupting the normal functioning of resident VSCs. Here, I establish that adipocytes have a negative influence on SC survival in culture. I also show that adipocytes and osteoblasts are responsible for the creation of distinct extracellular microenvironments, with unique expression patterns of several pro- and anti-angiogenic factors with known effects …

The Role Of Receptors For Advanced Glycation End-Products (Rage) And Ceramide In Cardiovascular Disease, Michael Bruce Nelson

Theses and Dissertations

Type 2 diabetes and cigarette smoke exposure are associated with an increased risk of cardiovascular complications. The role of advanced glycation end-products (AGEs) is already well-established in numerous comorbidities including cardiomyopathy. Given the role of AGEs and their receptor, RAGE, in activating inflammatory pathways, we sought to determine whether ceramides could be a mediator of RAGE-induced altered heart mitochondrial function. Using an in vitro model, we treated H9C2 cardiomyocytes with carboxy-methyl lysine-BSA, followed by mitochondrial respiration assessment. We found that mitochondrial respiration was significantly impaired in AGE-treated cells, but not when co-treated with myriocin, an inhibitor of de novo …

The Role Of C-Kit Receptor Tyrosine Kinase In Beta-Cell Proliferation, Function And Survival, Zhi Chao Feng

Electronic Thesis and Dissertation Repository

c-Kit, a receptor tyrosine kinase, interacts with Stem Cell Factor (SCF), mediating cell differentiation, function, and survival. c-Kit is critical for the development and maintenance of beta-cell function in both rodents and humans. The mutation of c-Kit at W locus (c-Kit^Wv/+) in mice results in an early onset of diabetes. However, the underlying mechanisms by which c-Kit deficiency leads to beta-cell failure are unknown. Therefore, studying SCF/c-Kit downstream signaling pathways is essential to understanding the precise mechanism by which c-Kit regulates beta-cell survival and function in vivo.

We identified that dysregulated Akt/Glycogen synthase kinase 3β (Gsk3β)/cyclin …

Islet Regenerative Properties Of Ex Vivo Expanded Hematopoietic Progenitor Cells, Ayesh K. Seneviratne

Electronic Thesis and Dissertation Repository

Human umbilical cord blood (UCB) progenitor cells with high aldehyde dehydrogenase activity (ALDH^hi), can stimulate endogenous islet regeneration after transplantation into mice with steptozotocin (STZ)-induced diabetes. However, UCB ALDH^hi cell are extremely rare, and expansion will be required to develop cell-mediated strategies to treat patients with diabetes. To increase the number of progenitor cells available for clinical application, we expanded ALDH^hi UCB cells under clinically applicable, serum-free hematopoietic-restricted conditions. 6 day expansion resulted in a 15-fold increase in total cell number, and a 3-fold increase in the number of HPC retaining high ALDH (ALDH^hi HPC) …

The Role Of Integrins In Support Of Pancreatic Function, Survival And Maturation, Matthew Riopel

Electronic Thesis and Dissertation Repository

The pancreas is a glandular organ composed of endocrine and exocrine compartments. Integrins are cell adhesion molecules that connect cells to the extracellular matrix (ECM). Integrins modulate a variety of cellular effects, yet their mechanism of action in the developed pancreas is not well understood. Fibrin is a provisional ECM protein that contains ligands for integrin receptors. Fibrin is capable of supporting islet health, but it is unclear how fibrin exerts its effects. The objective of this thesis is to understand the role of integrin receptors on in vivo pancreatic cell function, survival, and proliferation. In addition, this thesis investigates …

Glucosensing, Hypoglycemia, And The Brain, Candace Reno

All Theses and Dissertations (ETDs)

Glucose homeostasis can be peripherally and centrally mediated. Within the periphery, GLUT4 in muscle and adipose tissue is required for normal glucose homeostasis and disruption of GLUT4 translocation in these tissues leads to glucose intolerance and insulin resistance, hallmarks of Type 2 diabetes. Within the brain, specialized glucose sensing neurons regulate whole body glucose homeostasis. Unlike GLUT4's role in the periphery, brain GLUT4 regulation of glucose tolerance is not well defined. Understanding how brain glucose sensing, mediated by GLUT4, regulates glucose tolerance and insulin sensitivity will aid in the development of treatment strategies to protect against the pathogenesis of diabetes. …

Chromosomal Localization Of The Islet Neogenesis Associated Protein (Ingap) Gene In Syrian Hamster By Tyramide Signal Amplification-Fluorescence In Situ Hybridization (Tsa-Fish), Sallie A. Smith

Biological Sciences Theses & Dissertations

Diabetes mellitus is a group of conditions characterized by hyperglycemia due to an inability to produce or properly utilize insulin. The majority of cases fall into two categories, Type I and Type 2. Type I results from the autoimmune destruction of pancreatic β-cells of the islets. The beta cells are the exclusive source of insulin and the patient becomes entirely dependent on exogenous insulin to survive. Patients with Type 2 are distinguished by insulin resistance, a condition that develops due to the inability of the body to effectively use the insulin being produced. The β-cells gradually lose their ability to …

Abnormalities In Post-Translational Processing Of Platelet Rap 1b In Niddm: A Possible Cause Of Platelet Hyperactivity And Cardiovascular Disease In Diabetes, Elizabeth Ann Hall

Theses and Dissertations in Biomedical Sciences

Post-translational processing is critical for the appropriate subcellular localization and function of platelet G-proteins. The majority of the platelet responses to agonists are mediated through specific receptor/G-protein complexes. Therefore, G-protein activity is central to "normal" platelet activity (i.e. aggregation). We have shown that Simvastatin, the in vivo inhibitor of HMG CoA Reductase and therefore isoprenoid synthesis, inhibits the post-translational processing of specific platelet G-proteins and alters platelet responses to agonists. These results show the importance of post-translational processing of G-proteins to platelet activity. Altered post-translational processing of specific G-proteins may explain platelet hyperactivity and the increased incidence of cardiovascular disease …

The Effect Of Triiodothyronine On Glut4 Protein Expression In Skeletal Muscle And Adipose Tissue Of Obese-Diabetic (Db/Db) Mice, Paula Joanne Estrada

Theses Digitization Project

No abstract provided.