Sca-1 is an early-response target of histone deacetylase inhibitors and marks hematopoietic cells with enhanced function

Expression profiles of LSK cells stimulated for 24h in the presence or in the absence of of valproic acid (VPA) The molecular process that underlies the biological effects of valproic acid (VPA), a widely used histone deacetylase inhibitor, on HSPCs was investigated by studying the early-response genes of VPA. Genome-wide gene expression studies revealed overrepresentation of genes involved in glutathione metabolism, receptor and signal transducer activity and changes in the HSPCs surface profile following short, 24h VPA treatment. Sca-1, a well-known and widely used stem cell surface marker, was identified as a prominent VPA target.VPA strongly preserved Sca-1 expression on LSK cells, but also re-activated Sca-1 on committed progenitor cells that were Sca-1 negative, thereby reverting them to the LSK phenotype. We demonstrated that re-acquired Sca-1 expression coincided with induced self-renewal capacity as measured by in vitro re-plating assays, while Sca-1 itself was not required for the biological effects of VPA as demonstrated using Sca-1 deficient progenitor cells. We show that VPA can induce several genes involved in signal transduction of which Sca-1 was shown to mark cells with increased self-renewal capacity. These data consist of total mRNA obtained from hematopoietic cells cultured for 24h in the presence or absence of valproic acid. All samples were analyzed in independent biological triplicates.