Transcriptional plasticity, priming and commitment in hematopoietic lineages [RNA-seq]

Differentiation of adult hematopoietic stem cells (HSC) constantly produces the cell types of the blood and immune system. The dynamics of this process and the hierarchy of downstream oligopotent stem cell differentiation remain controversial. Here we dissect hematopoietic progenitor populations in a minimally biased fashion using extensive single cell sampling from murine bone marrow. We characterize the HSC population, define its quiescent transcriptional program and validate it with label retaining assays and cytokine mediated stimulations. Analysis of initial HSC commitment defines marked bifurcation of erythroid/megakaryocytic cells from myeloid/lymphoid lineages. Unexpectedly, we find states that mix transcription of pre-myeloid and pre-lymphoid genes. This suggests a model in which more than one differentiation trajectory can link HSC to several cell types. Dendritic cells are thus linked with both monocyte and lymphocyte precursors. Our data support a model of hematopoiesis balancing relaxation of an HSC quiescent state, gradual bifurcations and trans-differentiation. Bone marrow hematopoietic progenitors mRNA profiles from single cells were generated by deep sequencing of thousands of single cells, sequenced in several batches on an Illumina NextSeq Experiment was paired-end, but read2 was used to read cell and molecule barcodes only. Additional details about experimental design (associating each single cell with its amplification batch and index sorting readout) available as Series supplementary file.