This dissertation explores the intricate roles of polyunsaturated fatty acid (PUFA) metabolites, particularly oxylipins, in the pathology of neurodegenerative diseases and systemic lupus erythematosus (SLE), emphasizing their significance in disease diagnostics and therapeutics. We examined oxylipins' biosynthesis and physiological impacts, focusing on metabolic pathways, primarily cytochrome P450 and epoxide hydrolase (CYP-EH) metabolism. This work underscores the critical role of oxylipins as potential biomarkers, positioning lipidomics as a transformative frontier in biomedical research.Using the aging model organism Caenorhabditis elegans (C. elegans), we developed an analytical methodology to investigate the interplay between aging, neurodegenerative disease, and CYP-EH metabolism of PUFA. The method employing solid phase extraction, high-performance liquid chromatography coupled with tandem mass spectrometry (SPE-HPLC-MS/MS) was developed and validated to quantify nanomolar levels of potent oxylipins accurately and precisely in C. elegans across different ages and under various treatments. This analytical methodology will serve as a tool to significantly enhance our understanding of the molecular relationship between PUFA CYP-EH metabolism and aging-related diseases. Later, we investigate the impact of SLE pathogenesis on PUFA metabolism with a focus on the CYP-EH metabolic pathway. Through serum analysis from SLE and healthy Western populations, with the help of targeted lipidomics and comprehensive machine learning analysis, we found EH metabolites, such as 14,15-DiHETrE, to be significantly downregulated in subjects with SLE across different sexes, races, and age groups. Classification and regression machine learning analysis further revealed that some CYP-EH-derived oxylipins are important predictors of SLE, indicating a link with disease status and severity and identifying potential biomarkers. Studies show oxidative stress plays a critical role in both neurodegenerative disease and SLE. Lastly, we aimed to further understand the mechanisms behind oxidative stress and its connection with lipid metabolism. We investigated the impact of chemically induced oxidative stress on lipid and oxylipin profiles using C. elegans as an animal model. Methodologies include targeted LC-MS/MS and untargeted high-resolution mass spectrometry (HR-MS) analysis to monitor changes in oxylipin and lipid concentrations under oxidative stress conditions. The upregulation of dihydroxy PUFA metabolites alongside unchanged epoxy metabolites suggests enzyme regulation under oxidative stress. The findings of this pilot study reveal substantial alterations in oxylipin profiles and lipid concentrations, indicating a complex interplay between lipid metabolism and oxidative stress responses. This dissertation underscores the essential role of PUFAs and their CYP-EH metabolites in understanding disease mechanisms. It demonstrates how lipidomics, coupled with advanced analytical techniques such as targeted and untargeted mass spectrometry, can effectively identify biomarkers and therapeutic targets, acquire critical insights into cellular conditions and disease processes, and thereby advance personalized medicine.
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