Neogenin-1 distinguishes between myeloid-biased and balanced Hoxb5 ⁺ mouse long-term hematopoietic stem cells

Abstract

Hematopoietic stem cells (HSCs) self-renew and generate all blood cells. Recent studies with single cell transplants and lineage tracing suggest that adult HSCs are diverse in their reconstitution and lineage potentials. However, prospective isolation of these subpopulations has remained challenging. Here, we identify Neogenin-1 (NEO1) as a unique surface marker on a fraction of mouse HSCs labeled with Hoxb5, a specific reporter of long-term HSCs (LT-HSCs). We show that NEO1+Hoxb5+ LT-HSCs expand with age and respond to myeloablative stress in young mice while NEO1−Hoxb5+ LT-HSCs exhibit no significant change in number. Furthermore, NEO1+Hoxb5+ LT-HSCs are more often in the G2/S cell cycle phase compared to NEO1−Hoxb5+ LT-HSCs in both young and old bone marrow. Upon serial transplantation, NEO1+Hoxb5+ LT-HSCs exhibit myeloid-biased differentiation and reduced reconstitution while NEO1−Hoxb5+ LT-HSCs are lineage-balanced and stably reconstitute recipients. Gene expression analysis reveals erythroid and myeloid priming in the NEO1+ fraction and association of quiescence and self-renewal–related transcription factors with NEO1− LT-HSCs. Finally, transplanted NEO1+Hoxb5+ LT-HSCs rarely generate NEO1−Hoxb5+ LT-HSCs while NEO1−Hoxb5+ LT-HSCs repopulate both LT-HSC fractions. This supports a model in which dormant, balanced NEO1−Hoxb5+ LT-HSCs can hierarchically precede active, myeloid-biased NEO1+Hoxb5+ LT-HSCs.

Molecular and cellular mechanisms of aging in hematopoietic stem cells and their niches

“…Compared to young adult mice, elderly mice display a significant increase in the number of pHSCs (~ 17-fold for CD34 − LSK cells, [ 27 ] ~ 15-fold for LSK-CD48 − CD150 + , ~ 12-fold for CD34 − LSK-CD48 − CD150 + EPCR + , [ 58 ] ~ 5-fold for SP-LSK [ 52 ]and ~ 10-fold for CD34 − LSK-CD48 − CD150 + FLK2 − ) [ 59 ]. Nevertheless, transplantation studies suggested that the LT-ML HRC of the unpurified BM cells isolated from old mice is increased by only ~ twofold compared to young mice, which is consistent with the ~ 2-fold increase in functional HSCs determined by standard serial dilution and competitive transplantation assays [ 27 , 60 ].…”

“…The expression of several megakaryocyte–platelet markers, such as CD150 [ 31 ], CD41 [ 71 ], CD61 [ 72 ] and Vwf, [ 68 ] are increased in aged HSCs. In addition, Neogenin-1 (NEO1), a multifunctional transmembrane receptor, is also increased in aged HSCs [ 59 ]. By adding such markers to the well-defined pHSC panels, along with transplantation functional studies, several labs were able to largely isolate My-bi HSCs (CD150 hi , CD41 + , CD61 + , c-Kit hi , Vwf int or Neo1 + ) from Bala-HSCs (CD150 lo , CD41 − , CD61 − , c-Kit Int , Vwf lo or Neo1 − ) [ 71 , 73 ].…”

“…Although the Bala-HSCs in old mice express many myeloid and platelet genes, they retain normal lymphoid commitment potential when transplanted into a young BM microenvironment [ 31 , 59 , 188 , 189 ]. Even some Plt-/My-bi HSCs regain lymphoid differentiation potential upon transplantation into young mice.…”

Immuno-Modulation of Hematopoietic Stem and Progenitor Cells in Inflammation

“…In addition to the well-established HSC immunophenotypes, lineage - Sca-1 + c-Kit + (LSK), endothelial protein C (EPCR) ( 8 ), and the SLAM family proteins ( 9 ) used for the isolation of phenotypic hematopoietic stem and multipotent progenitors (HSPCs), others have been described to reflect HSC function by enriching for distinct lineage bias upon transplantation. Recently, Neogenin-1 (NEO1) was identified to distinguish NEO1 + HSCs primed toward myelopoiesis at the cost of lymphopoiesis from NEO1 - HSCs that show a balanced differentiation into both myelopoiesis and lymphopoiesis ( 10 ). NEO1 + Hoxb5 + HSCs expand with age while NEO1 - Hoxb5 + HSC counts remain unchanged as in young mice.…”

Niche derived netrin-1 regulates hematopoietic stem cell dormancy via its receptor neogenin-1

“…Neo1 can modulate cytoskeletal activities and can function as a co-receptor for bone morphogenetic proteins (BMPs) 40 , 41 . However, the functional role of Neo1 or its ligands such as Ntn1 in HSC biology remains uncertain 1 , 42 . Here, we identify Ntn1–Neo1 signalling as an important regulator of HSC quiescence.…”