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Selected Publication:
Triebl, A.
Sophisticated Analytical Methods for Lipidomics
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Graz Medical University; 2016. pp.
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- Authors Med Uni Graz:
- Advisor:
- Köfeler Harald
- Stojakovic Tatjana
- Trötzmüller Martin
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- Abstract:
- Lipids are biomolecules with enormous structural diversity and encompassing a plethora of biological functions. In particular this wide functional variety manifests itself in lipids being dysregulated in a number of diseases and pathological states, such as diabetes, Alzheimer’s, or various forms of cancer. The relatively young research field of lipidomics concerns itself exclusively with comprehensive analysis of lipids, including the elucidation of their functional pathways and interactions in biological systems. These goals demand sophisticated analytical methods to elucidate the various roles of lipids. To tackle the diverse analytical requirements of the lipidomic field, three approaches for use in lipidomic research, all using the methodology of liquid chromatography coupled to mass spectrometry, are presented. The first is a method for global analysis of the lipidome. It encompasses sample preparation using a simple liquid-liquid extraction method, high-performance liquid chromatography with the power to separate structural and even positional isomers of lipids, and high-resolution mass spectrometric detection together with a software package for automated data processing. Since quantitation is a crucial aspect of lipidomic analysis, the method has been validated in the biologically relevant range of lipids. Additionally, the tandem mass spectrometric behaviour of lipids has been extensively studied. This method is a prime choice for untargeted lipidomic analysis of even the most complex biological systems. The second approach describes a method for analysis of N-acylphosphatidylethanolamines, which are important signaling lipids present only in minute amounts. The analytes of interest are selectively isolated from complex biological matrices using a combination of liquid-liquid extraction and solid phase extraction, and analysed using two selected reaction monitoring transitions. This method enables quantative and simultaneous structural analysis of N-acylphosphatidylethanolamines. Finally, the applicability of lipidomic methodology in cancer research is presented. In a specialized approach using high resolution accurate mass tandem mass spectrometry, an aspect of energy metabolism of cancer cells is examined. By tracing a stable isotope labelled precursor, the incorporation of carbon from amino acids into the glycerol backbone of phospholipids is detected and quantified, showing that cancer cells are able to use amino acids as a glycerol source under low-glucose conditions.