Comprehensive Lipidome Profiling to Elucidate the Functional Role of Aberrant Lipid Metabolism in the Onset and Progression of Disease

The disruption of lipid metabolism pathways involved in the regulation of membrane structure, energy homeostasis and signaling are known to be associated with the onset and progression of various diseases, including cancer, diabetes and diabetic complications. To date, however, the systematic ‘lipidome level’ characterization of alterations in the array of individual lipid species that may occur under different physiological or pathological states, and examination of their functional roles in disease state progression, has not been broadly explored. To address this need, we have developed a comprehensive lipidome analysis strategy involving simultaneous extraction of both highly polar and nonpolar lipid species from tissue, cell or plasma samples, in situ sequential functional group specific chemical derivatization reactions, coupled with ultra-high resolution ‘shotgun’ mass spectrometry and ‘targeted’ tandem mass spectrometry (MS/MS). This strategy enables the routine identification, characterization and relative quantification of >1000 individual lipids across a broad range of lipid classes and sub-classes (glycerolipids, glycerophospholipids, sphingolipids and sterol lipids), in only 5-10 minutes data acquisition and analysis time, across more than 4 orders of magnitude dynamic range of abundance, and with minimal need for sample handling prior to analysis. In this presentation, I will describe the application of this strategy to (i) reveal statistically significant changes in lipids abundances and lipid subclass remodeling between a series of malignant and metastatic human colorectal cancer cell lines and their secreted exosomes, that have guided subsequent functional studies using targeted gene silencing and biochemical analysis methods to elucidate the functional role(s) of these lipids in malignant transformation, metastatic progression and exosome mediated cancer signaling, and (ii) monitor retina, vitreous and serum samples of type 1 diabetic (T1D) animal models and human clinical samples, in order to identify functional lipid biomarkers of diabetic retinopathy and its progression.