Identification of defects in the transcriptional program during lineage-specific in vitro differentiation of CD34⁺ cells selected from patients with both low- and high-risk myelodysplastic syndrome

Objective

Development of myelodysplastic syndrome (MDS) is suggested to follow a multistep pathogenesis and is characterized by accumulation of molecular defects of the hematopoietic stem/progenitor cells, resulting in aberrant differentiation and proliferation.

Materials and Methods

To detect alterations within the transcriptional program in MDS-derived CD34⁺ cells during lineage-specific differentiation, we performed serial gene expression analysis of in vitro differentiated erythro-, granulo-, and megakaryopoietic cells using oligonucleotide microarrays (HG-U133A, Affymetrix, Santa Clara, CA, USA). For selected genes, expression data were confirmed using real-time polymerase chain reaction.

Results

We identified genes with altered expression during lineage-specific differentiation in either low- or high-risk MDS cells compared to the expression patterns of continuously up- or downregulated genes from the normal transcriptional program of hematopoiesis. In cluster analyses, we could show that MDS samples have a distinct expression pattern of a set of selected genes compared to normal cells, which allows prediction of the affiliation of a sample to one group. Furthermore, this study gives an overview of genes that are differentially expressed in MDS cells compared to normal hematopoiesis.

Conclusion

Our data provide the first comprehensive transcriptional analysis of differentiating human CD34⁺ cells derived from MDS patients compared to normal individuals. It gives new insights into the alteration of differentiation and proliferation of MDS stem cells.