Hypoxia inducible factor 1α-driven steroidogenesis impacts systemic hematopoiesis

Area of Science:

• Hematology
• Immunology
• Endocrinology

Background:

• Glucocorticoids (GCs) are crucial for hematopoiesis.
• The impact of sustained high endogenous GC levels on hematopoietic stem cell (HSC) function and immune cell development is not well understood.

Purpose of the Study:

• To investigate the effects of chronically elevated endogenous GC levels on HSC function and immune cell development.
• To elucidate the role of glucocorticoid receptor (GR) signaling in these processes.

Main Methods:

• Utilized a mouse model (P2H1Ad.Cortex) with elevated systemic GC levels due to HIF1α deletion.
• Analyzed hematopoietic stem and progenitor cell (HSPC) populations phenotypically and functionally.
• Conducted transplantation assays and used GR-deficient bone marrow to assess GR signaling's role.

Main Results:

• Chronic GC exposure led to HSPC expansion, HSC quiescence, and metabolic restraint.
• HSCs exhibited enhanced regenerative capacity and superior chimerism post-transplantation.
• Myeloid progenitor output increased, while B-cell development was significantly impaired at the pre-pro-B-cell stage.

Conclusions:

• Chronic GC-GR signaling critically modulates HSC function, boosting myeloid output and hindering B-cell development.
• The P2H1Ad.Cortex mouse model is valuable for studying prolonged GC exposure effects on hematopoiesis.
• Findings may inform understanding of hematologic complications associated with chronic GC therapy.