Abstract
Human cord blood (CB) myeloid progenitor reprogramming to a high-fidelity human induced pluripotent stem cell (hiPSC) state can be achieved using non-integrating episomal vectors and stromal signals. These conventional, primed CB-hiPSC lines can subsequently be chemically reverted with high efficiencies to a blastomere-like Tankyrase/PARP Inhibitor-Regulated Naive Stem Cell (TIRN-SC) state with functional totipotency. PARP-regulated TIRN-SCs are human stem cells with high epigenetic plasticity, stable epigenomic imprints, and have greater differentiation potency than conventional, lineage-primed hiPSCs. Here, optimized XF/FF methods are outlined for efficient mesenchymal stroma-activated episomal reprogramming of CD34+ CD33+ CB myeloid progenitors into conventional XF/FF hiPSC. TIRN reversion reproducibly potentiated XF/FF conventional hiPSC to adopt transcriptional, epigenetic, and functional features of cleavage-stage human embryo cells with decreased lineage-primed gene expression. We validated that TIRN-reverted CB-derived XF-hiPSC displayed marked improvement in directed multi-lineage differentiation (including hematovascular lineages) across a broad repertoire of genetically independent backgrounds. These methods serve as a first step for generating cGMP-compliant TIRN-SC lines for clinical-grade HLA-defined 'Universal' donor TIRN-SC (UTIRN-SC) banks. The derivation of UTIRN-SC lines with improved differentiation versatility from CD34+ CD33+ CB progenitors could have a high impact on regenerative medicine. For example, UTIRN-SCs could generate tissue banks of HLA-defined, cryo-preserved cardiac, vascular, and neural donor progenitors for comprehensive multi-lineage "off-the-shelf" cellular therapies.