Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Metabolomic/lipidomic DESI imaging of different cell cultures (#774)

Hadeer Mattar 1 , Emrys Jones 2 , Heather Patsiouras 3 , Emmanuelle Claude 2 , Clare Mills 1
  1. Division of Infection, Immunity & Respiratory Medicine, University of Manchester, Manchester, UK
  2. Waters Corporation, Wilmslow, CHESHIRE, United Kingdom
  3. Waters Corporation, Sydney, NSW, Australia

Lipidomics provides a comprehensive structural and functional characterization of various lipids in different biological samples. Desorption electrospray ion source (DESI) has been currently used as a mass spectrometry imaging (MSI) technique for the analysis as well as the identification of lipids in the cell culture.

In this study, we aimed to investigate the distribution and the localisation of lipids among three different cell lines: two of the gut epithelial cell lines (Caco2 and HT29-MTX cells) and one of cancerous basophil cells (RBL=Rat Basophilic Leukemia) . We also aimed to identify the master charged lipids by applying positive and negative modes.

Three Cell lines were investigated which are; Caco2, HT29-MTX as a gut epithelial cells, and RBL as basophil leukemia. Data were acquired using a DESI source attached to a Xevo G2-XS mass spectrometer, with data acquired in both positive and negative mode. DESI spray conditions were set at 2┬Ál/min, 98:2 MeOH: water with nebulizing gas pressure of 5 bar.

Cell grown on cover slips had the media removed for the MSI experiment and were directly mounted onto microscope glass slides, using double sided tape and placed onto the DESI stage, with no sample preparation or pre-treatment.

Initial experiments were carried out in positive ion mode (50 um pixel) with mainly glycerophospholipids such as PC (34:1), K+ and triglyceraides being identified for all cell lines. However, differences in the lipid intensity profiles were observed between cell lines, including PC (36:4),K+ being over expressed in Caco2 whereas (PC(P-32:0), K+ was more pronounced in HT29-MTX. Furthermore, an experiment at 20um pixel size showed individual agglomerate of cells with a different distribution within the same cell line.

Negative ion mode showed a variety of molecular information for metabolite and lipid species, including oleic acid which was the most abundant in Caco2.