Master of Science, University of Akron, 2006, Biology

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Committee: Richard Londraville (Advisor) Subjects:

Master of Science, The Ohio State University, 2023, Chemistry

Food contaminated with Salmonella bacteria is the leading cause of foodborne illness in the United States. Due to the increased use of unnecessary antibiotic treatment, pathogen resistance to these drugs is growing, and a new drug target is necessary to develop alternative treatments for severe Salmonella infection. The role of Salmonella in host and microbiome disruption is well characterized in the gut, where it elicits a highly inflammatory environment with a strong immune response. Some groups are at risk for severe illness from a weakened immune response, including obese patients. Salmonella has the ability to translocate and infect other organs in the body, such as the liver. The immune response from the liver during infection is not well understood, so studies involving the comparison of disease state, healthy or infected, and diet, normal or high-fat, could elucidate processes and pathways that are significantly altered in the liver. Bottom-up proteomics is a powerful method used to study the entire proteome of a biological sample. Using this strategy combined with other sensitive and high throughput analysis methods, such as DIA mass spectrometry, these tools have the potential to quantify proteins across different diet and disease treatment groups for robust biological analysis. Here, the variable of diet type as well as the presence or absence of Salmonella infection, will be studied in the liver proteins of mice. By revealing the host proteome response to these factors, this research could lead to the development of targeted therapeutic treatments for the infection or the discovery of biomarkers for certain biological responses.

Committee: Brian C. Searle (Advisor); Vicki H. Wysocki (Advisor) Subjects: Chemistry

Doctor of Philosophy (PhD), University of Toledo, 2020, Biomedical Sciences (Molecular Medicine)

Obesity is a major epidemic in the US and abroad, and therefore, uncovering compelling, and novel methods for addressing this issue is paramount. We have previously shown that bilirubin activates the nuclear receptor transcription factor peroxisome proliferator-activated receptor α (PPARα) to induce β-oxidation, which reduces lipid accumulation in adipocytes and hepatocytes. RNA-sequencing in HepG2 hepatocytes showed that bilirubin-induced transcriptome responses are predominantly PPARα-dependent (~95%). To further elucidate this relationship, we studied the direct interaction of bilirubin and PPARα. We found that bilirubin was specific for the PPARα, and did not interact with the other PPAR isoforms, PPARβ/δ or PPARγ. Further analysis showed that the interaction of bilirubin-PPARα lowered lipid accumulation and increased mitochondrial respiration in both brown and white adipocytes cell lines. We found that mice with hyperbilirubinemia by either treatment or genetically, had increased mitochondria function and reduced white adipocyte size, but brown adipocytes were unaffected. Using the Pamgene Pamstation nuclear hormone receptor (NHR) chip technology, we found that bilirubin-induced coregulator recruitment to PPARα similar to other ligands fenofibrate and WY-14,643, and that this also occurred in animals with hyperbilirubinemia. Next, using CRISPR technology, we excised the gene that generates bilirubin, Blvra, in both mouse kidney and liver cells. The loss of the Blvra gene (BVRA protein) in kidney cells caused lipid buildup and lipotoxicity, which was reversed when cells were treated with bilirubin. The lipotoxic state in the kidney cells dysregulated phosphorylation of BAD and subsequent cell apoptotic pathways. In hepatocytes, the loss of Blvra diminished mitochondrial respiratory function. Here, using a plethora of techniques, we found that bilirubin is a metabolic hormone that binds directly to PPARα. Also, the BVRA enzyme is essential in the regulation of li (open full item for complete abstract)

Committee: Terry Hinds (Committee Chair); Robert McCullumsmith (Committee Member); Edwin Sanchez (Committee Member); Jennifer Hill (Committee Member); Beata Lecka-Czernick (Committee Member); Andrea Nestor-Kalinoski (Committee Member); David Stec (Committee Member) Subjects: Molecular Biology; Pharmacology; Physiology

PhD, University of Cincinnati, 2015, Medicine: Pathobiology and Molecular Medicine

In 2001, apolipoprotein (apo) A-V was discovered by two independent groups to be a strong plasma triglyceride (TG) modulator and a potential liver regeneration factor. ApoA-V knockout (KO) mice displayed 4-fold elevated plasma TG and transgenic mice showed 1/3 plasma TG compared with wildtype (WT) mice, indicating a strong inverse relationship between apoA-V expression and plasma TG levels. ApoA-V was also found upregulated 6 h after partial hepatectomy although its role in liver regeneration remains unknown. In humans, various apoA-V single nucleotide polymorphisms (SNPs) correlate with hypertriglyceridemia and risk for cardiovascular and metabolic diseases. Intravenous injection of apoA-V protein to apoA-V KO mice can lower plasma TG by 50%, demonstrating exogenous administration of apoA-V can alter plasma TG. For the past decade, a number of mechanisms have been proposed for apoA-V: 1) enhancing plasma lipolysis of TG-rich lipoproteins, 2) increasing hepatic uptake of lipoprotein remnant particles, and 3) influencing lipid droplet formation in the hepatocyte. However, apoA-V is only made in the liver and has a low plasma concentration: 1,000 times lower than apoB and 10,000 times lower than apoA-I on a molar basis. With its low plasma concentration, how apoA-V can so greatly modulate plasma TG levels has been unclear, particularly in the postprandial state. This dissertation investigates the role of apoA-V in dietary fat absorption and one potential mode of action of the liver-made protein on the gut. Previous reports showed that apoA-V suppressed the surge of TG-rich lipoproteins in the plasma after a dietary fat load. Since apoA-V is not made in the gut, mechanisms had focused on lipolysis with the gut largely ignored. We hypothesize that apoA-V affects the gut by suppressing the absorption rate of dietary TG. Using lymph fistula mice, we report that apoA-V deficiency dramatically enhances the production of chylomicrons, in both rate and particle number (open full item for complete abstract)

Committee: Patrick P.W. Tso Ph.D. (Committee Chair); James Heubi M.D. (Committee Member); Philip Howles Ph.D. (Committee Member); Anja Jaeschke Ph.D. (Committee Member); Min Liu Ph.D. (Committee Member); Laura Woollett Ph.D. (Committee Member) Subjects: Surgery

Doctor of Philosophy in Medicinal Chemistry, University of Toledo, 2009, Medicinal Chemistry

Type 2 diabetes (T2D) is a disease of cellular insulin resistance and a dysfunction of pancreatic beta cells resulting in aberrations of carbohydrate and lipid metabolism and a loss of tight control of blood glucose levels. Prior to the diagnosis of overt T2D, patients are often grouped into a diagnosis of the metabolic syndrome, a collection of related biochemical and anthropometric features including impaired glucose tolerance, central or visceral obesity, hypertension, and dyslipidemia. Research has implicated inflammation as a contributor to insulin resistance and the development of type 2 diabetes. The aim of this project is to investigate the role of inflammatory cells, particularly macrophages, and cytokines of the innate immune system, in the development and progression of the metabolic syndrome. It is now accepted that metabolic syndrome and T2D have an underlying component of sub-acute, chronic inflammation. Obese and T2D humans and mice both have elevated serum levels of pro-inflammatory cytokines and these cytokines have been linked directly to insulin resistance through effects on key molecules involved in insulin signaling and glucose uptake into cells. A thorough examination of the effects of diet, particularly high fat and Western (high fat and high carbohydrate/sugar) diets in mouse models of insulin resistance, compared to the same mice fed regular chow, should yield further understanding of the development and pathogenesis of obesity and T2D. These mouse strains have alterations in the CEACAM1 gene, which is a key mediator of hepatic insulin clearance and suffer from insulin resistance, mainly caused by prolonged insulin circulation due to a decrease in insulin clearance in the liver. High fat and Western diets are associated with weight gain, visceral adiposity, and liver mass increase. The relationship of insulin resistance to inflammatory markers from immune macrophages and T cells found within adipose tissue of special diet fed mice with modif (open full item for complete abstract)

Committee: Marcia McInerney Ph.D. (Advisor); Z. Kevin Pan Ph.D. (Committee Member); Hermann von Grafenstein Ph.D. (Committee Member); Katherine Wall Ph.D. (Committee Member) Subjects: Immunology