The reduced blood potential of NP-iPSC might be explained by residual epigenetic marks that restrict blood fates or a lack of epigenetic marks that enable blood formation. We sought to determine whether treatment of NP-iPSC with pharmacologic modulators of gene expression and DNA methylation might reactivate latent hematopoietic potential. We treated NP-iPSC in vitro with Trichostatin A (TSA), a potent inhibitor of histone deacetylase34, and 5-azacytidine (AZA), a methylation-resistant cytosine analogue35. After 18 days of drug treatment, the resulting cells displayed higher blood forming activity (NP-iPSC-TSA-AZA; Fig. 4b). For unclear reasons, tertiary reprogramming through blood intermediates or drug treatment of NP-iPSC produced altered ratios of colony sub-types, perhaps suggesting different efficiencies of lineage reprogramming.
