Transcription density map as a new tool for evaluation of various expression profiles: Ex vivo differentiation of CD34+ cells
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| Year of publication | 2006 |
| Type | Conference abstract |
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| Description | Microarrays technology is a very powerful tool for monitoring gene expression. In our experiments with CD34+ differentiation assays, we used Transcription density map (TDM) as a new tool for evaluation of expression patterns in enriched populations of different cell lineages. Hematopoietic stem cells (enriched in fraction of CD34+ cells) have the ability to regenerate hematopoiesis. This potential is clinically used in transplanting bone marrow or peripheral blood stem cells. TDM is an improved transcription map. Genes are mapped on chromosomes according to their offset in basepairs (instead of sequential ordering used by traditional transcription maps (TMs)). TDM clearly and exactly shows the differences in expression patterns of evaluated populations. We can see the differences in expression level between individual genes and also between gene families or chromosome regions. On the basis of TDM we can evaluate expression patterns in order to exclude potentially cancerous cell population during transplantation. We present the possibilities and the potential of TDM by evaluation of two different ways of immunomagnetic separation (positive selection of CD34+ cells and negative selection of Lin- cells) of CD34+ cells. The cells were ex vivo differentiated to granulocytes like cells. CD34+ and Lin- cells were enriched from peripheral blood stem cell (PBSC) grafts and bone marrow of patients with non-Hodgkin's lymphoma. Isolated cells were cultivated in the presence of peripheral blood stem cell cytokines, FLT-3 ligand, interleukin 3, interleukin 6, and granulocyte colony-stimulating factor. During 0th, 4 th, 7 th,9 th, 11 th and 14 th day, the cells were harvested and analyzed. cDNA microarrays analysis in combination with TDM of cultured hematopoietic cells confirmed the equivalence of the two enrichment methods for PBSC samples and helped us to characterize ex vivo cultured differentiated cells. Our methodological approach is helpful for characterizing ex vivo cultured hematopoietic cells and in addition it is also suitable for more general purposes. Equivalence of CD34+ and Lin- selection methods from PBSC samples confirmed by cDNA microarrays may have an implication for graft manipulation in an experimental setting of hematopoietic transplantation |
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