BioProject

While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. More...

While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. To determine how distinct progenitors can generate similar downstream lineages, we examined the transcriptional changes that accompany loss of in vivo myeloid potential as common myeloid progenitors (CMPs) differentiate into common dendritic cell progenitors (CDPs), and as lymphoid-primed multipotent progenitors (LMPPs) differentiate into all lymphoid progenitors (ALPs). Microarray studies revealed that Interferon regulatory factor 8 (IRF-8) expression increased during each of these transitions. Competitive reconstitutions using Irf8-/- bone marrow demonstrated cell-intrinsic defects in the formation of CDPs and all splenic dendritic cell subsets. Irf8-/- CMPs and, unexpectedly, Irf8-/- ALPs produced more neutrophils in vivo than their wild type counterparts at the expense of DCs. Retroviral expression of IRF-8 in multiple progenitors led to reduced neutrophil production and increased numbers of DCs, even in the granulocyte-macrophage progenitor (GMP), which does not normally possess conventional DC potential. These data suggest that IRF-8 represses a neutrophil module of development and promotes convergent DC development from multiple lymphoid and myeloid progenitors autonomously of cellular context. Overall design: CMP (Lineage-c-kithiSca-1-CD11c- CD34+ Flk2+CD16/32-CD115- ) or CDP (Lin-c-kitintSca-1-CD34+Flk2+CD16/32-CD115+) were double sorted from the bone marrow of wild type C57BL/6 mice. RNA was extracted from 10,000-30,000 sorted cells using Trizol (Invitrogen) and linear acrylamide (Ambion), amplified using Affymetrix Two-Cycle Amplification and IVT kits (Affymetrix), and hybridized to Affymetrix Mouse Genome 430 2.0 chips. Less...