Reactive oxygen species levels differentiate CD34⁺ human progenitors based on CD38 expression

Area of Science:

• Hematology
• Stem Cell Biology
• Cellular Biology

Background:

• Low reactive oxygen species (ROS) levels are characteristic of mouse hematopoietic stem cells (HSCs).
• Understanding ROS levels in human HSCs is crucial for stem cell research and transplantation.
• Human HSCs are typically identified as CD34+ CD38low cells.

Purpose of the Study:

• To quantify ROS levels in distinct human progenitor populations (CD34+ CD38low and CD34+ CD38high).
• To investigate ROS levels in human HSCs from bone marrow, cord blood, and mobilized peripheral blood.
• To validate findings by assessing the expression of the ROS scavenger GPX3.

Main Methods:

• Developed a multiparameter flow cytometry assay using H2DCFDA staining to quantify ROS.
• Sorted primary human CD34+ CD38low and CD34+ CD38high cells from bone marrow and cord blood.
• Assessed gene expression of GPX3 in sorted cell populations.

Main Results:

• CD34+ CD38low cells from bone marrow and cord blood exhibited significantly lower ROS levels compared to CD34+ CD38high cells and other leukocytes.
• A strong correlation between ROS levels and GPX3 expression was observed in sorted progenitor populations.
• Findings in human cells corroborate previously reported data in mouse HSCs.

Conclusions:

• Human CD34+ CD38low progenitors, analogous to mouse HSCs, maintain low ROS levels.
• The developed flow cytometry assay enables precise enumeration of repopulating primitive progenitors.
• This method can enhance monitoring during hematopoietic stem cell transplantation procedures.