BMP signalling differentially regulates distinct haematopoietic stem cell types.

Area of Science:

• Stem cell biology
• Molecular and developmental biology

Background:

• Adult hematopoiesis arises from distinct hematopoietic stem cell (HSC) subtypes with self-renewal and repopulating capabilities but varied lineage outputs.
• The molecular underpinnings of HSC heterogeneity remain largely unknown.
• Bone morphogenetic protein (BMP) signaling influences early HSC generation but its role in later stages is debated.

Purpose of the Study:

• To investigate the molecular basis of HSC heterogeneity.
• To determine the role of BMP signaling in regulating HSC subtypes and their lineage outputs.

Main Methods:

• Prospective isolation of two distinct HSC populations from murine fetal liver and bone marrow: BMP-activated and non-BMP-activated.
• Clonal transplantation assays to assess the repopulating ability and lineage output of isolated HSC subtypes.
• Analysis of intrinsic genetic programs differentiating the two HSC types.

Main Results:

• Two distinct HSC types, BMP-activated and non-BMP-activated, were identified and isolated.
• Clonal transplantation revealed that these HSC types possess different hematopoietic lineage outputs.
• The two HSC types exhibit distinct intrinsic genetic programs, supporting the role of BMP signaling in HSC heterogeneity.

Conclusions:

• The BMP signaling axis plays a critical role in regulating HSC heterogeneity and lineage output.
• These findings elucidate molecular control mechanisms defining HSC types.
• The study has implications for reprogramming cells to an HSC fate and for therapeutic strategies targeting specific HSC types.