Figure 6 – Comprehensive structural analysis of bone marrow microenvironment uncovers adipocytic localization of Lin− HSPCs.

A) Hierarchically clustered heatmap showing the normalized rank proximity from each microenvironmental structure to each structure. Data is from all 12 samples. Each structure was ranked by its proximity to each other structure in each sample, and the rank was normalized such that a value of 0 means most proximal and 1 means least proximal. The color scale was adjusted such that 0 is red and 1 is blue. B) Data-driven illustration of structural proximity in normal bone marrow. Edge lengths are scaled to the median normalized rank proximity (where lower numbers mean more proximal) of each structure, and the physical median distance across 12 samples is labeled above each line. C-D) Hierarchically clustered heatmap showing the normalized rank proximity of each neighborhood and cell type to each type of microenvironmental structure. Data is from all 12 samples, except when a cell type or neighborhood was too rare to rank in a sample. Each cell type or neighborhood was ranked by its proximity to each structure in each sample, and the rank was normalized such that a value of 0 means most proximal and 1 means least proximal. The color scale was adjusted such that 0 is red and 1 is blue. Grey color means that there weren’t enough cells (<10 in at least half of samples) in the annotated region to include in the analysis for that cell type. Immunophenotypic HSCs, CLPs, and Schwann cells were excluded completely from the cell type analysis by this criterion. E) Boxplot showing the normalized rank proximity of Lin− HSPCs (dashed outline) and Lin− SPINK2+ HSPCs (solid outline) to each microenvironmental structure. F) Representative CODEX images and associated CPMs from two samples showing the peri-adipocytic localization of both HSPCs and SPINK2+ HSPCs. G) Cartoon schematic showing the revised model of human myelopoiesis, where adipocyte-adjacent HSPCs give rise to the earliest myeloid committed cells, which migrate to mature in an arterio-endosteal niche, and finish their maturation and egress in the sinusoidal/central niche.