Medicine and Health Sciences Commons^™

Investigating The Effects Of Subchronic Dietary Zinc Supplementation On Diet-Induced Metabolic Dysfunction-Associated Steatotic Liver Disease., Oluwanifemi Esther Bolatimi

Electronic Theses and Dissertations

Zinc deficiency is associated with metabolic dysfunction-associated steatotic liver disease (MASLD). Previous studies show zinc supplementation improves steatosis, but its therapeutic effects in established MASLD remain unclear. We developed a model to characterize the effects of zinc supplementation on high-fat diet (HFD) induced MASLD and hypothesized established MASLD would be attenuated. Mice were fed control diet or HFD for 12 weeks and then grouped into normal or zinc-supplemented diets for 8 additional weeks. At euthanasia, plasma and liver tissues were collected for phenotypic analysis. Twelve weeks of HFD altered glucose clearance and body composition. Eight weeks of subsequent zinc supplementation …

Ethanol Dysregulates Sirt1-Mediated Lipogenic Signaling Pathways Through Α4*-Nicotinic Acetylcholine Receptors In Hepatocytes., Caitlin Christina Wilkerson

Electronic Theses and Dissertations

Alcohol-associated liver disease (ALD) is a broad spectrum of diseases ranging from steatosis to severe hepatic cirrhosis, none of which have any FDA approved therapies. Downregulation of hepatic Sirtuin 1 (Sirt1) activity by ethanol has been shown to lead to an upregulation of the pro-lipogenic gene targets under its jurisdiction, resulting in increased lipogenesis and triglyceride accumulation. It was hypothesized that ethanol acts on α4*-nicotinic acetylcholine receptors (α4*-nAChRs) in hepatocytes to decrease Sirt1 expression, which ultimately dysregulates lipid metabolic homeostasis. Ethanol’s effects were investigated in cultured AML12 hepatocytes and in WT primary mouse hepatocytes acutely exposed to ethanol. Consistent with …

Investigation Of Heterocyclic Amines And N-Acetyltransferase 2 Genetic Polymorphism In The Dysregulation Of Hepatic Energy Homeostasis: A Gene-Environment Approach., Kennedy M Walls

Electronic Theses and Dissertations

Heterocyclic amines (HCAs) are mutagens generated when cooking meat for prolonged periods of time or until well-done. Recent epidemiological studies reported significant associations between dietary HCA exposure and insulin resistance and type II diabetes. However, no previous studies have examined if HCAs, independent of meat consumption, contributes to pathogenesis of insulin resistance or metabolic disease. It is well known that HCAs require hepatic bioactivation by cytochrome P450 1A2 (CYP1A2) and N-acetyltransferase 2 (NAT2). NAT2 expresses a well-defined genetic polymorphism in humans that, depending on the combination of NAT2 alleles, correlate to rapid, intermediate, or slow acetylator phenotypes that exhibit differential …

Metabolic Foundations Of Exercise-Induced Cardiac Growth., Kyle Fulghum

Electronic Theses and Dissertations

Regular aerobic exercise promotes physiological cardiac growth, which is an adaptive response thought to enable the heart to meet higher physical demands. Cardiac growth involves coordination of catabolic and anabolic activities to support ATP generation, macromolecule biosynthesis, and myocyte hypertrophy. Although previous studies suggest that exercise-induced reductions in cardiac glycolysis are critical for physiological myocyte hypertrophy, it remains unclear how exercise influences the many interlinked pathways of metabolism that support adaptive remodeling of the heart. In this thesis project, we tested the general hypothesis that aerobic exercise promotes physiological cardiac growth by coordinating myocardial metabolism to promote glucose-supported anabolic pathway …

Beyond The Brain: A Study Of Α-Synuclein's Role In Bone And Adipose Tissue, Carolina A. Figueroa

Electronic Theses and Dissertations

α-Synuclein is a polypeptide encoded by the Snca gene, highly expressed in neurons, but it is also found in bones and adipose tissue. Co-expression analysis showed that Snca regulates skeletal homeostasis, and its deletion reduced estrogen deficiency-induced bone loss and weight gain. It is a major component of Lewy bodies (LB) in Parkinson’s disease (PD), leading to progressive immobilization and a range of nonmotor symptoms, including osteopenia, body composition alterations and insulin resistance. This thesis aimed to determine α-Synuclein’s intrinsic role in bone and adipose homeostasis. We discussed the PD pathophysiology emphasizing aspects of bone health and metabolism. By using …

Tissue-Resident Myeloid-Derived Suppressor Cells Modulate Immune Homeostasis In Healthy Adipose., Katlin Brooke Stivers

Electronic Theses and Dissertations

Our goal with this study was to gain insight into the homeostatic immune cell network in healthy adipose tissue. Specifically, we sought to determine if the immature myeloid cells found in healthy and inflamed adipose were, in fact, tissue-resident myeloid-derived suppressor cells (MDSCs). Using various in vitro and in vivo methods, we have uncovered a population of CD11b^Hi Ly6C^Hi Ly6G^- MDSCs resident in healthy adipose tissue. To the best of our knowledge this is the first time that these cells have been investigated and described in healthy adipose tissue. Systemic MDSC depletion lead to the accumulation of …

Epidermal Growth Factor Receptor (Egfr) Inhibition By Polychlorinated Biphenyls Contributes To Non-Alcoholic Fatty Liver Disease (Nafld)., Josiah Hardesty

Electronic Theses and Dissertations

This dissertation describes how poly-chlorinated biphenyls (PCBs) exacerbate the pathogenesis of non-alcoholic fatty liver disease (NAFLD). While PCBs were banned in 1979, they still persist in contaminated biota, including food, and are detected in human plasma and adipose. The body burden of PCBs is associated with elevation of liver enzymes and necrosis markers in humans, characteristic of NAFLD. PCB exposure in high-fat diet fed mice leads to steatohepatitis that recapitulate the findings seen in exposed humans. The global estimate of people diagnosed with NAFLD is up to 1 in 4 people, unrelated to dietary or genetic factors. The hepatic mechanisms …

The Effect Of Wild Blueberry Bioactives On Endothelial Cell Migration And Angiogenesis: An In Vitro Mechanistic, Genomic And Proteomic Approach, Panagiotis Tsakiroglou

Electronic Theses and Dissertations

The goal of this study is to investigate the effects of wild blueberry fractions (Anthocyanins and Phenolic acids) on vascular function and physiology. More specifically the potential effects of the above fractions and their combination in physiological concentrations on endothelial cell migration, angiogenesis, gene expression and proteins synthesis of markers related to the above processes. The objectives are to study whether anthocyanins, phenolic acids and their combinations (ACNs:PAs) affect: a) cell proliferation, b) speed of endothelial cell migration, c) angiogenesis, d) gene expression of genes critical for cell migration and angiogenesis such as RAC1, RHOA, AKT1, eNOS and VEGF and …

Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor

Electronic Theses and Dissertations

Metabolomics, the study of small molecules in biological systems, has enjoyed great success in enabling researchers to examine disease-associated metabolic dysregulation and has been utilized for the discovery biomarkers of disease and phenotypic states. In spite of recent technological advances in the analytical platforms utilized in metabolomics and the proliferation of tools for the analysis of metabolomics data, significant challenges in metabolomics data analyses remain. In this dissertation, we present three of these challenges and Bayesian methodological solutions for each. In the first part we develop a new methodology to serve a basis for making higher order inferences in metabolomics, …

Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle

Electronic Theses and Dissertations

Background: Human arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic metabolizing enzyme found in almost all tissues. NAT1 can additionally hydrolyze acetyl-coenzyme A (acetyl-CoA) in the absence of an arylamine substrate. NAT1 expression varies inter-individually and is elevated in several cancers including estrogen receptor positive (ER+) breast cancers. Additionally, multiple studies have shown the knockdown of NAT1, by both small molecule inhibition and siRNA methods, in breast cancer cells leads to decreased invasive ability and proliferation and decreased anchorage-independent colony formation. However, the exact mechanism by which NAT1 expression affects cancer risk and progression remains unclear. Additionally, consequences …

Alpha-Amino Methylation And Acetylation Are Novel Regulators Of Myl9 Function., Christopher David Nevitt

Electronic Theses and Dissertations

Dysregulation of alpha-amino post-translational modifications (Nα-PTMs) is found in multiple cancers and developmental disorders. However, the exact roles Nα-PTMs play in regulating protein function remain poorly understood. I sought to clarify the role of Nα-methylation and Nα-acetylation in the regulation of Myosin Regulatory Light Chain 9 (MYL9). MYL9 is a key cytoskeletal regulator and transcription factor and is the first protein confirmed to undergo both Nα-methylation and Nα-acetylation. Through this work I revealed novel regulatory features of MYL9, while also presenting a framework by which to understand the coordinated regulation of proteins by Nα-methylation and Nα-acetylation. Nα-PTM selective mutants of …

Perceptual Variations In Thermoregulation During Exercise In A Hot Environment, William C. Alger

Electronic Theses and Dissertations

ABSTRACT

Professionals are seeking to find ways to prevent exertional heat illness (EHI) in populations working in hot environments as well as populations that are physically active. The purpose of the present study was to evaluate individuals’ ability to accurately perceive core temperature ranges associated with homeothermic and EHI temperatures during exercise. Ten physically active males exercised on a treadmill at a self-selected rate until core temperature reached 39°C. Participants rated perceived core and skin temperature on 100 mm scales each time core temperature increased 0.25˚ C (37.5-39.0˚ C), along with thermal comfort and sweating sensation. During exercise core temperature …

Vinyl Chloride-Diet Interactions In Liver Disease : Potential Roles Of Autophagy And Energy Management., Anna L. Lang

Electronic Theses and Dissertations

Vinyl chloride (VC) is a prevalent environmental toxicant that has been shown to cause liver injury at high, occupational exposures. However, most studies have not addressed interactions of low doses with risk-modifying factors. This study aims to explore low-level VC metabolite exposure interactions with other potential risk-modifying factors and their effect on underlying liver disease. We examined sub-hepatotoxic effects of a VC metabolite (chloroethanol, CE) in two murine models of liver injury using ethanol and lipopolysaccharide (LPS). In both, CE significantly enhanced liver injury when compared to either ethanol or LPS alone. Previous studies have shown an increase in mTOR …

Acrolein Is A Critical Mediator Of Alcohol-Induced Liver And Intestinal Injury In Alcoholic Liver Disease., Wei-Yang (Jeremy) Chen

Electronic Theses and Dissertations

Alcohol consumption can cause alcoholic liver disease (ALD), which remains a major cause of morbidity and mortality in the United States. Chronic alcohol consumption causes a pro-oxidant environment in the liver and increases hepatic lipid peroxidation. Acrolein is the most reactive and toxic aldehyde generated through lipid peroxidation. Acrolein forms protein adducts and triggers endoplasmic reticulum (ER) stress and hepatocyte apoptosis, which are recognized etiologic factors in ALD. Several studies have established the critical role of the gut-liver axis in ALD pathogenesis, wherein alcohol-induced gut barrier dysfunction contributes to liver injury. This study investigates, in vitro and in vivo, the …