Desorption electrospray ionization mass spectrometry reveals lipid metabolism of individual oocytes and embryos

PLoS One. 2013 Sep 20;8(9):e74981. doi: 10.1371/journal.pone.0074981. eCollection 2013.

Abstract

Alteration of maternal lipid metabolism early in development has been shown to trigger obesity, insulin resistance, type 2 diabetes and cardiovascular diseases later in life in humans and animal models. Here, we set out to determine (i) lipid composition dynamics in single oocytes and preimplantation embryos by high mass resolution desorption electrospray ionization mass spectrometry (DESI-MS), using the bovine species as biological model, (ii) the metabolically most relevant lipid compounds by multivariate data analysis and (iii) lipid upstream metabolism by quantitative real-time PCR (qRT-PCR) analysis of several target genes (ACAT1, CPT 1b, FASN, SREBP1 and SCAP). Bovine oocytes and blastocysts were individually analyzed by DESI-MS in both positive and negative ion modes, without lipid extraction and under ambient conditions, and were profiled for free fatty acids (FFA), phospholipids (PL), cholesterol-related molecules, and triacylglycerols (TAG). Principal component analysis (PCA) and linear discriminant analysis (LDA), performed for the first time on DESI-MS fused data, allowed unequivocal discrimination between oocytes and blastocysts based on specific lipid profiles. This analytical approach resulted in broad and detailed lipid annotation of single oocytes and blastocysts. Results of DESI-MS and transcript regulation analysis demonstrate that blastocysts produced in vitro and their in vivo counterparts differed significantly in the homeostasis of cholesterol and FFA metabolism. These results should assist in the production of viable and healthy embryos by elucidating in vivo embryonic lipid metabolism.

MeSH terms

  • Animals
  • Blastocyst / chemistry
  • Blastocyst / cytology
  • Blastocyst / metabolism*
  • Cattle
  • Cells, Cultured
  • Embryo, Mammalian / chemistry
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / metabolism*
  • Lipid Metabolism*
  • Lipids / analysis*
  • Oocytes / chemistry
  • Oocytes / cytology
  • Oocytes / metabolism*
  • Principal Component Analysis
  • Real-Time Polymerase Chain Reaction
  • Spectrometry, Mass, Electrospray Ionization / methods*

Substances

  • Lipids

Grants and funding

AFGS was supported from the German Academic Exchange Service (DAAD) and the Fundación Gran Mariscal Ayacucho (FUNDAYACUCHO); VP was supported from the “L’Oreal/UNESCO Italia per le Donne e la Scienza 2013” grant; CF was supported from the Purdue University Center for Cancer Research Small Grants and from the Brazilian National Council for Scientific and Technological Development (CNPq); RGC by NSF IDBR 0852740. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.