EPCR expression marks UM171-expanded CD34⁺ cord blood stem cells

Area of Science:

• Hematology
• Stem Cell Biology
• Molecular Biology

Background:

• Hematopoietic stem cells (HSCs) are crucial for blood formation and are often expanded ex vivo for therapeutic purposes.
• UM171 is a small molecule agonist known to promote HSC self-renewal.
• Endothelial protein C receptor (EPCR), also known as CD201 or PROCR, is a protein involved in coagulation and inflammation.

Purpose of the Study:

• To identify reliable markers for UM171-expanded human cord blood HSCs.
• To investigate the role of EPCR expression in HSC function and repopulating capacity.

Main Methods:

• Flow cytometry analysis of human cord blood CD34+ cells treated with UM171.
• In vivo repopulation assays in immunocompromised mice.
• Assessment of EPCR expression stability in cell culture.
• Gene overexpression studies of EPCR in HSCs.

Main Results:

• A subset of UM171-treated CD34+ cells expressed EPCR.
• EPCR-positive cells demonstrated robust multilineage repopulation and serial reconstitution in mice.
• EPCR expression remained stable in culture, unlike other markers like CD38.
• Engineered EPCR overexpression did not replicate UM171 effects, but EPCR expression was necessary for HSC repopulating activity.

Conclusions:

• EPCR is a stable and reliable marker for UM171-expanded human cord blood HSCs.
• EPCR expression is essential for the repopulating potential of human HSCs.
• This finding facilitates the identification and selection of potent HSCs for research and potential therapeutic applications.