Published by the National Center for Biotechnology Information
MYC-mediated pathogenesis in lung cancer continues to attract interest for new therapeutic strategies. In this study, we describe a transgenic mouse model of KRAS-driven lung adenocarcinoma that affords reversible activation of MYC, used here as a tool for lipidomic profiling of MYC-dependent lung tumors formed in this model. Advanced mass spectrometric imaging and surface analysis techniques were used to characterize the spatial and temporal changes in lipid composition in lung tissue. We found that normal lung tissue was characterized predominantly by saturated phosphatidylcholines and phosphatidylglycerols, which are major lipid components of pulmonary surfactant. In contrast, tumor tissues displayed an increase in phosphatidylinositols and arachidonate-containing phospholipids that can serve as signaling precursors.
The novel LESAPLUS surface analysis approach combines the standard liquid extraction surface analysis with an additional step of a nano liquid chromatography separation.
The new Liquid Extraction Surface Analysis (LESA) mode of the TriVersa NanoMate can now be combined with nano liquid chromatography and a smaller extraction drop size of 400 µm to result in a powerful novel surface analysis mode. Resulting in the detection of small molecule drugs from tissue sections, residue on plant material or lipid profiles from brain sections of mouse.
Residues and contaminants in the food chain are an increasing problem due to high production volumes, large area distribution and import/export of food items across the world. The novel LESAPLUS surface analysis approach combines the standard liquid extraction surface analysis with an additional step of a nano liquid chromatography separation. This combination is ideally suited to investigate residues and contaminants on surfaces of interest and allows both rapid and direct screening as well as in depth analysis of suspect food samples.
Spatial lipid composition, distribution and regulation are very important factors for mediating lipid functionality and, when disrupted, can cause pathophysiological processes leading to cancer, obesity, atherosclerosis, and neurodegeneration. The novel LESAPLUS surface analysis approach combines the standard liquid extraction surface analysis with an additional step of a nano liquid chromatography separation. This combination is ideally suited to investigate small molecule drugs, metabolites or lipids from thin tissue sections.
M. Montowska, M.R. Alexander, G.A. Tucker, D.A. Barrett
Anal Chem. 2014 Oct 21;86(20):10257-65. doi: 10.1021/ac502449w
In this Article, our previously developed ambient LESA-MS methodology is implemented to analyze five types of thermally treated meat species, namely, beef, pork, horse, chicken, and turkey meat, to select and identify heat-stable and species-specific peptide markers. In-solution tryptic digests of cooked meats were deposited onto a polymer surface, followed by LESA-MS analysis and evaluation using multivariate data analysis and tandem electrospray MS. The five types of cooked meat were clearly discriminated using principal component analysis and orthogonal partial least-squares discriminant analysis. 23 heat stable peptide markers unique to species and muscle protein were identified following data-dependent tandem LESA-MS analysis. Surface extraction and direct ambient MS analysis of mixtures of cooked meat species was performed for the first time and enabled detection of 10% (w/w) of pork, horse, and turkey meat and 5% (w/w) of chicken meat in beef, using the developed LESA-MS/MS analysis. The study shows, for the first time, that ambient LESA-MS methodology displays specificity sufficient to be implemented effectively for the analysis of processed and complex peptide digests. The proposed approach is much faster and simpler than other measurement tools for meat speciation; it has potential for application in other areas of meat science or food production.
The Liquid Extraction Surface Analysis (LESA) capability of the TriVersa NanoMate enables simple, direct nanoESI mass spectrometric analysis from a variety of surfaces.
The new LESAPLUS allows for automated LESA experiments plus additional nano-LC separation through the ChipSoftX operating software with Developers Kit. This enhancement is ideal for direct tissue analysis.
ChipSoftX is an entirely new operating software for the TriVersa NanoMate automated nanoelectrospray source. Besides improvement in program compatibility with Windows and integration of existing software features, it also provides access to the new Developers Kit – a platform for customized method development with direct access to robot controls allowing entirely novel analysis workflows such as LESAPLUS.
Native mass spectrometry seeks to probe noncovalent protein interactions in terms of protein quaternary structure, protein–protein and protein–ligand complexes. The ultimate goal is to link the understanding of protein interactions to the protein environment by visualizing the spatial distribution of noncovalent protein interactions within tissue. Previously, we have shown that noncovalently bound protein complexes can be directly probed via liquid extraction surface analysis from dried blood spot samples, where hemoglobin is highly abundant. Here, we show that the intact hemoglobin complex can be sampled directly from thin tissue sections of mouse liver and correlated to a visible vascular feature, paving the way for native mass spectrometry imaging.
R.L. Griffiths and H.J. Cooper Anal. Chem., 2016, 88 (1), pp 606–609
Rian Griffiths, Alex Dexter, Andrew Creese and Helen J Cooper Analyst, 2015, Accepted Manuscript DOI: 10.1039/C5AN00933B
Liquid extraction surface analysis (LESA) is a surface sampling technique that allows electrospray mass spectrometry analysis of a wide range of analytes directly from biological substrates. Here, we present LESA mass spectrometry coupled with high field asymmetric waveform ion mobility spectrometry (FAIMS) for the analysis of dried blood spots on filter paper. Incorporation of FAIMS in the workflow enables gas-phase separation of lipid and protein molecular classes, enabling analysis of both haemoglobin and a range of lipid (phosphatidylcholine or phosphatidylethanolamine, and sphingomyelin species) from a single extraction sample. The work has implications for multiplexed clinical assays of multiple analytes.
