Single cell proteomics characterization of bone marrow hematopoiesis with distinct Ras pathway lesions

Area of Science:

• Hematology
• Molecular Biology
• Cell Biology

Background:

• Normal hematopoiesis relies on hematopoietic stem cells (HSCs) to produce diverse blood cells.
• HSCs must balance dormancy and proliferation, but the impact of genetic alterations on their frequency, potential, and metabolism is unclear.

Purpose of the Study:

• To investigate how induced expression of KRAS ^G12D or RasGRP1 affects HSC frequency, lineage potential, and metabolism.
• To understand the distinct effects of Ras pathway alterations at single-cell resolution.

Main Methods:

• Comparative analysis of normal hematopoiesis with induced KRAS ^G12D or RasGRP1 expression.
• Single-cell resolution CyTOF proteomics to assess cell populations.
• SCENITH™ assay to quantify protein synthesis and metabolic rates at single-cell precision.

Main Results:

• Both KRAS ^G12D and RasGRP1 induce myeloid lineage skewing.
• RasGRP1 leads to HSC and progenitor expansion, while KRAS ^G12D causes depletion.
• RasGRP1-expressing cells maintain a quiescent fraction, unlike KRAS ^G12D-expressing cells, despite both showing elevated metabolism in immature cells.

Conclusions:

• Ras pathway alterations differentially impact HSC and progenitor compartments and their metabolic states.
• These findings provide mechanistic insights into altered hematopoiesis at single-cell resolution.
• The study offers a valuable resource for understanding genetic impacts on blood cell production.