[Histone Deacetylase Inhibitors in the in Vitro Expansion of Hematopoietic Stem Cells].

The self-renewal and differentiation of hematopoietic stem cells(HSCs)are highly regulated by epigenetic modification,in which histone acetylation can activate or silence gene transcription.Histone deacetylase inhibitors(HDACIs)can inhibit the activity of histone deacetylase in HSCs to increase histone acetylation.A variety of HDACIs,such as trichostatin A and valproic acid,are used to expand HSCs in vitro,especially cord blood HSCs,combined with cytokines in serum-free culture to obtain more long-term repopulating cells.HDACIs promote the transcription of pluripotent genes related to stem cell self-renewal and inhibit the expression of genes related to differentiation,so as to promote the expansion and inhibit differentiation of HSCs.The expansion of cord blood HSCs by small molecular HDACIs in vitro is expected to improve the quantity of cord blood HSCs.The further research will focus on high-throughput screening for the most powerful HDACIs and the highly selective HDACIs,exploring the combination of epigenetic modifiers of different pathways.