Global analyses of cellular lipidomes directly from crude extracts of biological samples by ESI mass spectrometry: a bridge to lipidomics

Abstract

Lipidomics is a rapidly expanding research field in which multiple techniques are utilized to quantitate the hundreds of chemically distinct lipids in cells and determine the molecular mechanisms through which they facilitate cellular function. Recent developments in electrospray ionization mass spectrometry (ESI/MS) have made possible, for the first time, the precise identification and quantification of alterations in a cell's lipidome after cellular perturbations. This review provides an overview of the essential role of ESI/MS in lipidomics, presents a broad strategy applicable for the generation of lipidomes directly from cellular extracts of biological samples by ESI/MS, and summarizes salient examples of strategies utilized to conquer the lipidome in physiologic signaling as well as pathophysiologically relevant disease states. Because of its unparalleled sensitivity, specificity, and efficiency, ESI/MS has provided a critical bridge to generate highly accurate data that fingerprint cellular lipidomes to facilitate insight into the functional role of subcellular membrane compartments and microdomains in mammalian cells. We believe that ESI/MS-facilitated lipidomics has now opened a critical door that will greatly increase our understanding of human disease. -Han, X., and R. W. Gross. Lipidomics is a rapidly expanding research field fueled by recent advances in, and novel applications of, electrospray ionization mass spectrometry (ESI/MS). Lipidomics is focused on identifying alterations in lipid metabolism and lipid-mediated signaling processes that regulate cellular homeostasis during health and disease. Research in lipidomics incorporates multiple techniques to quantify the precise chemical constituents in a cell's lipidome, identify their cellular organization (subcellular membrane compartments and domains), delineate the biochemical mechanisms through which lipids interact with each other and with crucial membrane-associated proteins, determine lipid-lipid and lipid-protein conformational space and dynamics, and quantify alterations in lipid constituents after cellular perturbations. Through the detailed quantification of a cell's lipidome (e.g., lipid classes, subclasses, and individual molecular species), the kinetics of lipid metabolism, and the interactions of lipids with cellular proteins, lipidomics has already provided new insights into health and disease. The true power and promise of lipidomics, however, is only beginning to be realized.Decades of painstaking research in the 1970s and 1980s developed a straight and reversed-phase HPLC system that could "rapidly" (30 min) separate phospholipid classes, molecular species, and regioisomers into individual chemical constituents (1-6). These techniques, however, were labor intensive and required sensitive separation methods for which quantitation was difficult, because the → * transition during UV detection was not strictly proportional to mass content (7). Moreover, these procedures could not meet the needs for the application of lipidomi...

Alkaline methanolysis of lipid extracts extends shotgun lipidomics analyses to the low-abundance regime of cellular sphingolipids

“…Electrospray ionization mass spectrometry; Shotgun lipidomics; Shotgun sphingolipidomics; Sphingolipidome; Lysosphingomyelin; Psychosine; Sphingomyelin; Sphingosine Lipidomics, the large-scale study of the pathways and networks of cellular lipids, is an emerging and rapidly expanding research field [1][2][3]. Currently, lipidomics research has been focused on identifying alterations in lipid metabolic pathways and networks induced by a disease state, a gene mutation (knockout or overexpression), a therapeutic treatment, or other perturbations.…”

“…In the future, research in lipidomics will expand to include the dynamics of lipidomes, subcellular organizations of lipidomes, and interactions of lipids with lipids, proteins, and other cellular moieties. Although lipidomics has emerged as a distinct field only within the past few years [1][2][3], numerous new discoveries and/or advances have already been made [3][4][5][6][7][8][9][10][11][12]. Its essential roles in identifying the biochemical mechanisms of lipid metabolism, investigating the functions of an individual gene of interest, identifying novel biomarkers, and evaluating drug efficacy, among others, are becoming increasingly recognized.…”

Plasma lipidomics reveal profound perturbation of glycerophospholipids, fatty acids, and sphingolipids in diet-induced hyperlipidemia

“…Metabolomics is a nontargeted quantitative analysis of biofluids and tissues for low molecular mass endogenous metabolites. Lipidomics, as a branch of metabolomics, was first introduced by Han and Gross in 2003 [47]. Lipidomics has been defined as "the full characterization of lipid molecular species and of their biological roles in expression of proteins involved in lipid metabolism and function, including gene regulation" [48].…”

Dynamic simulation of cardiolipin remodeling: greasing the wheels for an interpretative approach to lipidomics

“…Lipid molecular species were identifi ed, quantifi ed, and acyl chain designation determined using a MDMS-SL approach as previously described ( 1,5,30,31 ). Product-ion analyses of cardiolipin molecular species by using a high mass accuracy/high resolution mass spectrometer [i.e., Orbitrap-LTQ mass spectrometer (Thermo Scientifi c San Jose, CA)] were also preformed as previously described ( 32 ) to verify the presence of very low abundance cardiolipin isomers.…”