3D Polypeptide Facilitates the Expansion of Rare, Circulating Peripheral Blood Hematopoietic Stem/Progenitor Cells with Repopulating Capabilities
Hematopoietic stem/progenitor cells (HSPCs) have been successfully used in treating malignancies but with limited cell sources. Whether circulating HSPCs (cHSPCs) in nonmobilized peripheral blood (PB) with engraftment capability could be expanded remains elusive. Here, we developed a polypeptide three-dimensional culture system (3DCS) to expand cHSPCs in nonmobilized PB. We demonstrated that cHSPCs exhibited self-renewal and multilineage differentiation potential by in vitro and in vivo assays including serial transplantation assays. Moreover, we found that 3DCS-derived cHSPCs increased by ~10-fold in vitro and by more than 300-fold in vivo. Bulk RNA-Seq and high-throughput qRT-PCR revealed that cHSPCs showed expression patterns that were similar to those of bone marrow-derived CD34+ HSPCs. Single-cell RNA-Seq elucidated that the 3DCS produced a milieu of immunosuppression that included heterogenous HSPCs and Treg cells. Cytokine arrays illustrated that that 3DCS secreted cytokines, including TNF-a essential for HSPC survival. In conclusion, 3DCS facilitates the expansion of cHSPCs with repopulating capabilities, providing cells for personalized precision medicine. Overall design: Single-cell RNA sequencing analysis was applied to detect the dynamic changes of cell types in 3DCS with normal PBMNCs derived from two donors. The samples at day0, day5, Day10 and day14 were collected and prepared for subsequent droplet-based scRNA-seq production according to the manufacturer's protocol (10x Genomics, CA, USA). Libraries were sequenced on the Illumina Hiseq X10 platform according to the manufacturer's instructions (Illumina).