Identification and Characterization of Subpopulations within Human Embryonic Stem Cell Lines

The Microarray study was designed to characterize the whole genome transcription profile of two subpopulations of H1 human embryonic stem cells we identified by size using flow cytometry.The heterogeneous nature of stem cells is an important issue in both research and therapeutic use in terms of directing cell lineage differentiation pathways, as well as self-renewal properties. Using flow cytometry we have identified two distinct subpopulations by size within the H1 and BGN1 human embryonic stem (hES) cell lines. Both populations express stem the cell markers Oct-4, Nanog, Tra-1-60, Tra-1-80 and SSea-4 and express very low levels of differentiation markers common to the three germ layers. To investigate if the two populations possessed different transcription profiles, we performed whole genome microarray analysis, and identified approximately 400 genes with significant differential expression (p<0.01). Cloning experiments indicate that both populations are able to repopulate each other and maintain the parental population. The large cell population responds to retinoic acid (RA) differentiation as evidenced by greater than a 50% loss of gated cell number and loss of Oct-4 expression; while the small cell population number does not change and maintains Oct-4 protein expression. The presence of these two populations could be vitally important with respect to stem cell therapy and research as they respond differently to differentiation signals, which may be important in directing stem cell differentiation for disease therapy.

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Annab LA, Bortner CD, Sifre MI, Collins JM, Shah RR, Dixon D, Karimi Kinyamu H, Archer TK