ATP2B1 expression identifies human hematopoietic stem cells with superior repopulation and self-renewal

Area of Science:

• Hematology
• Stem Cell Biology
• Molecular Biology

Background:

• Long-term hematopoietic stem cells (LT-HSC) are crucial for lifelong blood production and self-renewal.
• Human LT-HSC are known to be heterogeneous, varying molecularly, functionally, and across developmental stages.
• Identifying markers to resolve LT-HSC heterogeneity is challenging due to a lack of specific immunophenotypic tools.

Purpose of the Study:

• To identify novel cell surface markers that can resolve heterogeneity within human LT-HSC populations.
• To investigate the functional and molecular differences between LT-HSC subpopulations defined by the novel marker.
• To provide a framework for dissecting molecular programs underlying LT-HSC heterogeneity.

Main Methods:

• Utilized immunophenotypic analysis to identify cell surface markers on LT-HSC.
• Employed single-cell (sc) clonogenic assays to assess functional differences of LT-HSC subpopulations.
• Conducted molecular profiling using scMultiome and immunofluorescence microscopy.

Main Results:

• Identified ATPase plasma membrane calcium transporting 1 (ATP2B1/PMCA1) as a cell surface marker heterogeneously expressed on CD49f+ LT-HSC.
• ATP2B1 expression stratified LT-HSC from fetal liver, cord blood, and adult mobilized peripheral blood into distinct functional subpopulations.
• CD49f+ATP2B1+ LT-HSC demonstrated superior in vivo long-term repopulation and self-renewal compared to CD49f+ATP2B1- LT-HSC.
• Molecular profiling revealed enrichment of HSC self-renewal programs, including the TFEB-endolysosomal axis, in CD49f+ATP2B1+ LT-HSC.

Conclusions:

• ATP2B1 serves as a valuable immunophenotypic marker for dissecting human LT-HSC heterogeneity.
• The ATP2B1 marker stratifies LT-HSC into functionally distinct subpopulations with differential self-renewal capacities.
• This study provides insights into the molecular basis of LT-HSC heterogeneity, particularly the role of the TFEB-endolysosomal axis in self-renewal.