Expression profiling by high throughput sequencing
Summary
Integration of index sorting and single cell functional assays allowed identification of novel haematopoietic stem cell (HSC) and multiprogenitor subsets (MPP) that differ in their lineage differentiation potential in vitro and in vivo, cell cycle properties and long-term repopulation capacity in the NSG xenograft model. Here we report single cell transcriptomes of CD49f+ HSCs as well as those of CD49f+ Subset1 (CD19- CD38- CD45RA- CD90+ CD49f+ CD34lo CLEC9Ahi, Myelo-erythroid-skewed in vitro but Lymphoid-competent) and CD49f+ Subset2 cells (CD19- CD38- CD45RA- CD90+ CD49f+ CD34hi CLEC9Alo, Myelo-Lymphoid competent but Erythroid-deficient). We also report bulk transcriptomes of pools of 20 cells from HSC/MPP Subset1 (CD19- CD38- CD45RA- CD34lo CLEC9Ahi) and HSC/MPP Subset2 (CD19- CD38- CD45RA- CD34hi CLEC9Alo). Altogether these data show a diffuse transcriptional landscape of the CD49f+ HSC compartment, which is polarised along an axis that separates Myelo-Erythroid and Myelo-Lymphoid lineage-priming. Consistently with their differentiation capacity in vitro, CD49f+ Subset1 cells cluster at the Myelo-Erythroid end of the landscape, while CD49f+ Subset2 cells cluster at the Myelo-Lymphoid end. In addtion, these lineage-priming signatures were found to be more marked in HSC/MPP Subset1 and HSC/MPP Subset2, than in the equivalent CD49f+ subsets. In conclusion, 49f+ Subset1 and 49f+ Subset2 populations have activated distinct transcriptional lineage-priming programmes corresponding to the phenotypic lineage-skewing observed in vitro, that then become reinforced within the broader HSC/MPP pool. Altogether our data shows that lineage-priming and lineage-restriction programmes are initially established within the CD49f+ HSC subset in humans.
Overall design
Examination of the genome-wide transcriptome of 143 49f+ HSC Subset2, 142 LMPPs, 143 MLPs, 142 HSC/MPP Subset2