Mission Statement: To provide the highest quality quantitative lipid measurements from biological samples, including cells, tissue, serum, and media. The lab offers automated sample preparation and two distinct mass spectrometry platforms, enabling various specific services, ranging from shotgun lipidomics to isotope labeling and mathematical modeling of lipid flux parameters. Our full-service lab also provides data analysis and consultation services, which provide users with accurate analysis of lipid metabolic parameters.
Adapted from Lipid Maps
Shotgun Lipidomics
The mammalian lipidome is exceedingly complex and chemically diverse. It has been estimated that cells and plasma contain thousands of distinct lipid species from many lipid classes and subclasses. Mass Spectrometry is the standard analytical assay used to identify the lipids used by cells or found in plasma. The UCLA Lipidomics Lab uses a specific analytical approach called shotgun lipidomics to determine the identity and amounts of a lipid found in biological fluids, cells, or tissues. This analytical pipeline uses differential mobility (DMS)- based direct infusion-tandem mass spectrometry. We also perform the lipid extractions on samples using a semi-automated pipeline to ensure the highest accuracy for lipidomics studies.
The instrumentation used by the Lipidomics Lab is currently a SCIEX 5500 triple-quadrupole (QQQ) with a Shimadzu auto-sampler configured for direct infusion, with a SelexION ion mobility device, and Shimadzu LC. Built on the original Sciex Lipidyzer Platform, the DMS-based lipidomics platform uses 70 lipid standards sourced from Avanti Polar Lipids to provide accurate, quantitative measurements of over 1400 lipid species across 17 lipid subclasses within a biological sample. the current approach by the UCLA Lipidomics Lab uses an advanced analytical workflow called Shotgun Lipidomics Assistant (SLA), developed by the team at the Lipidomics Lab. Want to learn more about the development of this analytical platform? Click here. Or click on the link below to learn how to perform lipidomics at UCLA.
Compositional Analysis
Interested in determining the total long-chain fatty acids and cholesterol composition of the cells, fluids, or tissues in your experimental system? The UCLA Lipidomics Lab uses a quantitative Gas Chromatography-Mass Spectrometer (GC-MS) assay to measure the amounts of a biological sample's fatty acid and cholesterol. This assay uses in situ extraction and derivitization to break down the esterified lipids in complex lipids (e.g., phospholipids and triacylglycerols, cholesterol esters) into constituent fatty acids and cholesterol. The liberated fatty acids are chemically modified to facilitate measurement with a GC-MS.
This assay is also compatible with stable isotope labeling to determine the origin of a fatty acid or cholesterol found in a cell and gain insights into the synthetic capacity of a cell. Using 13C-labeled metabolites (e.g., glucose or glutamine), followed by extraction and derivitization, and GC-MS, we can determine the enrichment of the labeled metabolite into newly synthesized fatty acids and cholesterol. This GC-MS data is then analyzed with a mathematical model called isotopic spectral analysis (ISA) method to estimate metabolic flux and lipid synthesis rates. We can also calculate the contribution of a given carbon source to the Acetyl-CoA pool used for lipid synthesis with this method. Although more complex and labor-intensive, this approach can provide amazing insights into the metabolic pathways used by cells. Want to learn more about how the data generated with this platform can be used? Click here for one of the many interesting papers using this method.