PTPσ inhibitors promote hematopoietic stem cell regeneration

Area of Science:

• Biochemistry
• Hematology
• Molecular Biology

Background:

• Protein tyrosine phosphatase-sigma (PTPσ) is mainly found in neurons, regulating neural regeneration.
• PTPσ is also expressed in hematopoietic stem cells (HSCs).

Purpose of the Study:

• To identify and characterize small molecule inhibitors of PTPσ that can promote HSC regeneration.
• To evaluate the therapeutic potential of these inhibitors in preclinical models.

Main Methods:

• Systemic administration of PTPσ inhibitors (DJ001 and analog) to irradiated mice.
• Assessment of HSC regeneration, hematologic recovery, and survival rates.
• Evaluation of DJ001 in mice treated with 5-fluorouracil chemotherapy.
• In vitro treatment of human HSCs with DJ001 followed by in vivo repopulation studies.

Main Results:

• DJ001 administration promoted HSC regeneration, accelerated hematologic recovery, and improved survival in irradiated mice.
• DJ001 accelerated hematologic recovery in mice undergoing 5-fluorouracil chemotherapy.
• DJ001 demonstrated high specificity for PTPσ, acting via non-competitive, allosteric binding.
• DJ001 suppressed radiation-induced HSC apoptosis by activating RAC1 and inducing BCL-X_L.
• DJ001 treatment promoted regeneration of human HSCs capable of multilineage in vivo repopulation.

Conclusions:

• Selective, small-molecule PTPσ inhibitors like DJ001 show significant therapeutic potential for enhancing human hematopoietic regeneration.
• DJ001 offers a promising strategy for mitigating hematopoietic damage caused by radiation and chemotherapy.