Theses and Dissertations at Montana State University (MSU)
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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 Enhancing the antibiotic susceptibility of Pseudomonas aeruginosa biofilms by quorum sensing inhibition(Montana State University - Bozeman, College of Letters & Science, 2006) Huff, Caol Philipp; Chairperson, Graduate Committee: Thomas S. LivinghouseBiofilm forming bacteria are industrially and medically relevant organisms that are exceptionally resistant to garden variety antimicrobial treatments. This resistance is due in part to a biofilm forming bacteria's ability to sense and communicate with neighboring bacteria. As a result of this intercellular communication, bacteria are able to cooperate as a complex community. This communication system is used to modulate important facets of biofilm behavior and thus is an attractive target for biofilm control and potential antimicrobial agents. Inhibition of the molecular signaling system used by biofilm forming bacteria could lead to an effective treatment of chronic bacterial infections by interrupting the communication that promotes biofilm formation. Specifically, this will be accomplished be preparing synthetic analogues of signaling molecules possessing the N-acyl homoserine lactone structural motif. This structural component is well conserved among the signaling molecules in biofilm forming bacteria and it is hoped that these analogues will inhibit biofilm formation in Pseudomonas aeruginosa.