Clonal analysis of murine HSC self-renewal and differentiation in native hematopoiesis

Hematopoietic stem cells (HSC) maintain lifelong hematopoiesis. However, in current clonal analyses with unbiased "barcoding" approaches, steady-state hematopoietic clones in young and middle-aged adults rarely have detectable HSCs, which precludes comprehensive interrogation of HSC clonal behaviors. In the current study, we used the previously described Sleeping Beauty transposon model to investigate HSC self-renewal and differentiation at a clonal level following a lifelong chase that significantly enriched HSC-derived clones. From seventeen mice, we detected over seventy thousand clones in native hematopoiesis that reflected the known HSC differentiation biases observed in transplantation. Our data indicated an intimate connection between megakaryocytic-restricted differentiation and HSC self-renewal expansion. By comparing the differentiation patterns of clones derived from transplanted HSCs, we further demonstrated the abilities of HSCs to preserve their cell fates towards self-renewal or multilineage differentiation. Unlike HSCs, clonal expansion in multipotent progenitors was associated with either a differentiation-active or differentiation-indolent state. Moreover, the clonal expansion events in the more differentiated stem and progenitor cells, but not the most primitive HSCs, drove clonal expansion in the megakaryocyte and myeloid cell lineages. Our study provided a comprehensive portrait of native hematopoiesis at a clonal level and revealed the general patterns in which HSCs maintained self-renewal and multi-lineage differentiation.