Interleukin-12 Supports Self-renewal Division of Mouse Hematopoietic Stem Cells in Polyvinyl Alcohol-Based Culture.

Recombinant human serum albumin (rHSA) and polyvinyl alcohol (PVA) have been used as substitutes of fetal bovine serum to support in vitro self-renewal of mouse hematopoietic stem cells (HSCs). However, how the PVA exert this expansion effect and whether we could optimize a superior culture condition with PVA are still elusive. Here, we tried to illustrate this effect using highly purified murine HSCs by performing series single-cell techniques such as single-cell colony assay, single cell transplantation, and single cell transcriptome analyses. We found that PVA supported the self-renewal potential in HSCs better than rHSA partially by maintaining the fitting mechano-properties of HSCs including stiffness, adhesion, and viscoelastic. Next, we revealed that interleukin 12 (IL-12) maintained long-term (LT) HSCs and expanded short-term (ST) HSCs as well as did thrombopoietin (TPO) in the presence of PVA. However, there was no synergistic effect between IL-12 and TPO. Transcriptomic and metabolomic analyses indicated that HSCs cultured with IL-12 were more enriched in stemness-like transcriptional programs with increased expression of key regulators, such as Mecom, Mllt3, and Hlf, and minimized activation-associated oxidative stress, which were also accompanied by the glycolysis-favored metabolic profile as evidenced by mass spectrometry analysis. In summary, this study showed that IL-12 supported self-renewal divisions of LT-HSCs and ST-HSCs in PVA culture by maintaining HSC-like states transcriptionally and metabolically. These results provide a rationale for the effect of IL-12 in PVA culture and optimize a superior culture condition for murine HSCs.