Theses and Dissertations at Montana State University (MSU)
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Item Investigations of the gut-brain-metabolism axis in familial dysautonomia(Montana State University - Bozeman, College of Letters & Science, 2023) Cheney, Alexandra Marie; Co-chairs, Graduate Committee: Frances Lefcort; Valerie Copie; This is a manuscript style paper that includes co-authored chapters.Familial dysautonomia (FD), a neurodevelopmental and neurodegenerative disease primarily present in Eastern European Jewish populations, is a useful model system to explore the effects of neuronal dysregulation, particularly in the developing field of the gut-brain-metabolism axis. FD originates from a single genetic mutation in the ELP1 gene and differs from other neurological diseases, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and autism that are dependent on multiple factors. Metabolic and gut impairments have been observed in FD patients, but only symptom management has been pursued without further exploration into the underlying disease pathophysiology. To better understand how the gut environment changes as a result of neuronal dysregulation and how this impacts the gut-brain-metabolism axis in FD patients, several studies of both human and FD mouse model samples were undertaken. Serum and stool samples from FD patients and their relatives were analyzed for metabolic alterations using proton nuclear magnetic resonance (1H NMR)-based metabolomics. Stool samples from both a human cohort and FD mice were also analyzed for gut bacterial diversity via 16S rRNA gene sequencing. Additionally, stool metabolomes of FD mice were analyzed for metabolic alterations. The FD mouse model enabled us to explore how gut physiology changed during disease progression using gut histological methods and gut function assays. Our studies demonstrated significant changes in the metabolomes and gut microbiomes of FD patients compared to their healthy relative controls. Additionally, the FD mouse model, a pan-neuronal Elp1 conditional knock out, was sufficient to drive metabolic and gut microbiome changes, and impair gut barrier function compared to control mice. When FD mice cohabitated with healthy control mice and were able to exchange gut microbes via stool consumption, the cohoused FD mice improved in overall health and gut function. Our studies found that the gut microbiome and metabolome of cohoused FD mice were comparable to their cohoused control counterparts. Overall, this work has enhanced our understanding of the gut-brain-metabolism axis in Familial dysautonomia and has provided insights into underlying molecular mechanisms, which may be potential targets for therapeutic interventions, including the use of metabolic supplements and/or altering the gut microbiome.Item Characterization of osteoarthritis metabolism: a mass spectrometry based-approach(Montana State University - Bozeman, College of Letters & Science, 2024) Welhaven, Hope Diane Aloha; Co-chairs, Graduate Committee: Brian Bothner and Ronald K. June II; This is a manuscript style paper that includes co-authored chapters.Osteoarthritis (OA) effects 7% of the global population, equating to more than 500 million people worldwide, and is the leading cause of disability. Its multifaceted etiology includes risk factors ranging from genetics, to aging, obesity, sex, race, and joint injury. OA manifests differently across the patient population where symptom severity, rate of progression, response to treatment, pain perception, as well as others vary person to person posing significant challenges for effective management and prevention. At the cellular level, imbalanced matrix catabolism and anabolism contribute to the breakdown of cartilage, underlying bone, and other tissues affected by OA. Leveraging mass spectrometry-based techniques, particularly metabolomics, offers a promising avenue to dissect OA metabolism across musculoskeletal tissues, while considering individual patient-specific risk factors. Therefore, the goals of this research were to: (1) comprehensively characterize OA phenotypes and endotypes and (2) explore OA pathogenesis within the context of disease-associated risk factors. The first area of research focuses on profiling OA phenotypes and endotypes across disease development. These results provide clear evidence of OA-induced metabolic perturbations in OA cartilage and bone and elucidate mechanisms that shift as disease progresses. Several metabolites and pathways associated with lipid, amino acid, matrix, and vitamin metabolism were differentially regulated between healthy and OA tissues and within OA endotypes. The second area of research focuses on the impact of OA risk factors -- sex, injury, obesity, loading -- on the metabolism of circulatory fluids (i.e., serum, synovial fluid) and chondrocytes. Identification of metabolic indicators of disease, such as cervonyl carnitine, and metabolic pathways associated with these risk factors holds potential for improving screening, monitoring disease progression, and guiding preventative strategies. Overall, this work contributes to our current understanding of OA, its diverse metabolic landscape, risk factors and their interactions. Moreover, it lays the groundwork for personalized medicine by providing detailed insights into individualized phenotypic profiles, thereby advancing the prospect of tailored treatment strategies for OA individuals.Item The relationship between physiological stress response and variation in omics data(Montana State University - Bozeman, College of Letters & Science, 2021) Steward, Katherine Fay; Chairperson, Graduate Committee: Brian Bothner; This is a manuscript style paper that includes co-authored chapters.Omics analysis is the cornerstone of systems biology. It offers comprehensive assessments of stress, interaction networks and connections to phenotype. Defining a stressed phenotype can be challenging, however, as stress response mechanisms can arise from a range of environmental conditions and experimental perturbations. Previous work from our lab noted the possibility of a relationship between stress in omics data and the variation of that data. This connection has yet to be clearly defined, and the cellular mechanisms responsible for the canalization of omics data remain a mystery. In this work I have taken advantage of the sensitivity of metabolomics and proteomics to detect cellular stress and characterize its relationship to variation. By utilizing coefficient of variation (CV) as a statistic of merit, the depth of the relationship between stress and variation can be uncovered. Once the model was clearly defined, a proteomics dataset with a large proportion of protein coverage was utilized to investigate what pathways might be responsible for the metabolite and protein canalization.Item Quantitative 1 H NMR analyses of immunometabolic modulation in human macrophages(Montana State University - Bozeman, College of Letters & Science, 2019) Fuchs, Amanda Lee; Chairperson, Graduate Committee: Valerie Copie; Sage M. Schiller was an author and Wyatt J. Keegan, Mary Cloud B. Ammons, Brian Eilers, Brian Tripet and Valerie Copie were co-authors of the article, 'Quantitative 1 H NMR metabolomics reveals distinct metabolic adaptations in human macrophages following differential activation' in the journal 'Metabolites' which is contained within this dissertation.; Sage M. Schiller was an author and Isaac R. Miller, Mary Cloud B. Ammons, Brian Eilers, Brian Tripet and Valerie Copie were co-authors of the article, 'Pseudomonas aeruginosa planktonic- and biofilm-conditioned media elicit divergent responses in human macrophages' submitted to the journal 'PLoS pathogens' which is contained within this dissertation.Macrophages are innate immune cells that are found ubiquitously in nearly all human tissues, where they support host innate and adaptive immune responses in an effort to maintain systemic homeostasis. They are inherently plastic in nature and can dramatically modulate their functional phenotype according to pathogen and microenvironmental stimuli. Previous studies have shown that macrophages are particularly important for the resolution of inflammation in acute wound healing, which is marked by a phenotypic transition of wound macrophages from pro-inflammatory to anti-inflammatory. Chronic, or non-healing, wounds, such as diabetic, pressure, and venous leg ulcers, feature a prolonged host inflammatory response due in part to aberrant wound macrophage behavior. Non-healing in chronic wounds has also been shown to be dependent upon the establishment of pathogenic biofilms, which are more resistant to host defense mechanisms than planktonic, or free-floating, bacteria. Therefore, investigating macrophage dysregulation in the presence of bacterial biofilms has gained considerable interest. Here, 1D 1 H NMR-based metabolomics was utilized to identify metabolic pathways that are differentially modulated following primary human monocyte-derived macrophage activation with pro-inflammatory or anti-inflammatory stimuli relative to resting macrophages. Metabolic profiling of inflammatory macrophages indicated a substantial increase in oxidative stress as well as a decrease in mitochondrial respiration. These metabolic profiles also provided evidence that inflammatory macrophages divert metabolites from de novo glycerophospholipid synthesis to inhibit oxidative phosphorylation. In addition, we investigated which metabolic pathways are differentially modulated following primary human monocyte-derived macrophage exposure to Pseudomonas aeruginosa planktonic- and biofilm-conditioned media. Metabolic profiling of PCM- and BCM-exposed macrophages indicated a significant depletion of intracellular glucose without elevation of downstream glycolytic products. These metabolic patterns suggest that PCM- and BCM-exposed macrophages potentially divert glycolytic intermediates towards inositol phosphate metabolism. Overall, our studies provide additional support to previous findings, generate novel results regarding metabolic modulation of human macrophages following activation and exposure to planktonic- vs. biofilm-conditioned media, and contribute new insight to the field of immunometabolism.Item Marine natural products : isolation, identification, and modification of secondary metabolites from Briareum polyanthes, and from Tedania ignis and its associated microorganisms(Montana State University - Bozeman, College of Letters & Science, 1995) Cronan, John Michael