"One of the most interesting aspects of metabolomics is how little we know," commented Siuzdak. "We don't know what the vast majority of metabolites are, or what they do. It is an area ripe for discovery."
Research in metabolomics is made possible by a variety of special techniques and equipment. In the current study, the team used liquid chromatography-mass spectrometry (LCMS), which draws on two more traditional techniques to provide scientists with the ability to chemically analyze virtually any molecular species. The group then analyzed the resulting data using an open-access bioinformatics platform XCMS, a now-popular technique developed by Siuzdak and colleagues described in a 2006 article in the journal Analytical Chemistry. The XCMS software allows researchers to identify and assess metabolite and peptide features that show significant change between sample groupsin this case mouse stem cells versus mature cells.
The most difficult part of untargeted metabolomics studies is analyzing the results and characterizing metabolites, according to Research Associate Oscar Yanes of the Siuzdak lab, the new paper's first author.
Nevertheless, Yanes shifted though the data on stem cells and identified an unexpected pattern: stem cell metabolites had highly unsaturated structures compared with mature cells, and levels of highly unsaturated molecules decreased as the stem cells matured. Highly unsaturated molecules, which contain little hydrogen, can easily react and change into many other different types of molecules.
"The study reveals an astounding cellular strategy," commented Yanes. "The capacity of embryonic stem cells to generate a whole spectrum of cell types characteristic of different tissues (a phenomenon referred to as plasticity) is mirrored at the metabolic level."
"We were not expecting these results," said Si
|Contact: Keith McKeown|
Scripps Research Institute