BioProject

The human blood system is maintained through the differentiation and massive amplification of a limited number of long-lived hematopoietic stem cells (HSCs). More...

The human blood system is maintained through the differentiation and massive amplification of a limited number of long-lived hematopoietic stem cells (HSCs). Perturbations to this process underlie a diverse set of diseases, but the clonal contributions to human hematopoiesis and how this changes with age remain incompletely understood. While recent insights have emerged from barcoding studies in model systems, simultaneous detection of cell states and phylogenies from natural barcodes in humans has been challenging, which has limited the ability to explore functional differences between HSC clones. Here, we introduce an improved single-cell lineage tracing system based on deep detection of naturally-occurring mitochondrial DNA (mtDNA) mutations with simultaneous readout of transcriptional states and chromatin accessibility. We use this system to define the clonal architecture of HSCs, and map the physiological state and output of these clones. We uncover functional heterogeneity in HSC clones, which is stable over months and manifests as differences in total HSC output as well as biases toward the production of different mature blood and immune lineages. We also find that the diversity of HSC clones decreases dramatically with age leading to an oligoclonal structure with multiple distinct clonal expansions. Our study thus provides the first clonally-resolved and cell-state aware atlas of human hematopoiesis at single-cell resolution revealing an unappreciated functional diversity of human HSC clones both in young and aged individuals and more broadly paves the way for refined studies of clonal dynamics across a range of tissues in human health and disease. Overall design: We developed single-cell Regulatory multi-omics with Deep Mitochondrial mutation profiling (ReDeeM), which is a modified massive parallel single cell protocol to simultaneously profile multi-omics with deep mtDNA sequencing based on the 10X Genomics platform. With ReDeeM, three separate libraries are generated, including enriched mtDNA library for deep sequencing and mutation profiling, RNA library for gene expression, as well as ATAC library for chromatin accessibility profiling, all of which are linked via matchable single cell barcodes. Following the principle of our previous work, we firstly modified the droplet-based 10X genomics multi-omics protocol (Catalog #100283) by processing the whole cell instead of nuclei with fixation and mild permeabilization to maximally retain mitochondrial DNA. Next, we designed mtDNA specific probe sets to enrich the mitochondrial fragments using DNA hybridization. The RNA and ATAC library preps follow the standard 10X protocol with some modifications. More method details are described in the method section and an open ReDeeM Protocol is available. ReDeeM is further computationally supported by consensus variant calling pipeline redeemV , and an inhouse R package redeemR for the downstream mutation quality control, as well as single cell phylogenetic and integrative analysis. This SubSeries contains data of CRISPR mouse lineage tracing with ReDeeM Less...