Use of bioenergetic profiling to generate biomarkers of stem cell potential.

Stem cells have great potential for use in regenerative medicine and for basic research into mechanisms of human diseases. Two types of stem cell with particularly useful properties are human embryonic stem cells (hESC) and induced pluripotent stem cells (iPSC), both of which have the ability to renew themselves indefinitely and to become almost any type of specialized cell, which could be used to treat disease. The ability of hESC and iPSC cells to self-renew and maintain their special properties has traditionally been assessed using a set of stem cell genes and surface markers. However, testing for these markers is usually invasive and/or destructive and is only qualitatively related to the stem cell?s potential. We believe that such potential can be revealed by measuring the metabolism of stem cells; especially the way they generate energy to grow and develop. In our proposal we will compare the ?energy profile? of hESCs with that expressed by iPSC and non-stem cells to provide robust biomarkers of stem cell potential and viability. We have extensive experience of this kind of approach from working with early embryos, the source of embryonic stem cells. Specifically, we have shown that embryo metabolism can be linked to successful development and ultimately the capacity to give rise to a pregnancy. We expect to discover similar links between the metabolism, health and function of stem cells and believe that our project could play a key role in the translation of stem cell research from the laboratory to the clinic.

Human Embryonic Stem cells (hESC) have the ability to self-renew and to differentiate into a diverse range of specialized cells which may potentially be used in regenerative medicine and for basic research into disease mechanisms. Parallel opportunities are provided by the re-programming of somatic cells into pluripotent stem cells (so-called iPSC). Criteria for the successful establishment of embryonic stem cell potential have traditionally involved the expression of a panel of genes and surface antigens or the formation of teratomas in mice. However, the relationship of many of these markers to underlying cell biology is not clear, particularly when used as a ?snapshot? of the state of an entire culture,. By contrast, and drawing upon our research on early embryos, we hypothesise that stem cells can be characterised in terms of their metabolic phenotype and related cellular physiology. This proposition will be tested by comparing the metabolism, specifically the bioenergetics, of pluripotent cells (hESC lines, iPSC lines, human teratocarcinoma cells) and more differentiated cells at 3 levels of ?resolution? ? entire cell populations in culture, small colonies of cells and single cells ? and over time. Many of the metabolic/bioenergetic markers are non-invasive, allowing the data to be related to secondary analysis of cell biology and physiology. In this way, we aim to develop a range of novel markers of stem cell viability and potential. Our proposal will extend the boundaries of knowledge of stem cell biology beyond the genome and transcriptome-level by examining functional metabolic processes in real time.