CLASP2 safeguards hematopoietic stem cell properties during mouse and fish development.

Area of Science:

• Cell Biology
• Developmental Biology
• Hematopoiesis

Background:

• Hematopoietic stem cells (HSCs) rely on cell surface receptors for self-renewal and multipotency.
• Proper receptor expression involves complex trafficking, recycling, and degradation pathways.
• The roles of the microtubule network and Golgi apparatus in embryonic/fetal hematopoiesis are not well understood.

Purpose of the Study:

• To investigate the role of CLASP2, a microtubule-associated protein, in HSC development.
• To determine the impact of CLASP2 deficiency on HSC self-renewal and stemness.
• To elucidate the mechanisms underlying HSC dysfunction in the absence of CLASP2.

Main Methods:

• Utilized mouse and zebrafish models to study embryonic/fetal hematopoiesis.
• Analyzed HSC production, self-renewal, and stemness markers.
• Investigated cell surface receptor expression, specifically c-Kit.
• Examined cellular trafficking, lysosomal degradation, and Golgi apparatus function.

Main Results:

• Absence of CLASP2 significantly reduced overall HSC production in both species.
• CLASP2-deficient HSCs exhibited impaired self-renewal and loss of stemness.
• Decreased cell surface expression of the c-Kit receptor was observed.
• This was linked to increased lysosomal degradation and reduced plasma membrane trafficking of c-Kit.
• Dysfunctional Golgi apparatus was identified as a potential cause in CLASP2-deficient HSCs.

Conclusions:

• CLASP2 is crucial for maintaining HSC production, self-renewal, and stemness during development.
• CLASP2 regulates HSC stemness through control of c-Kit receptor cell surface expression.
• Golgi apparatus dysfunction and altered protein trafficking/degradation are key mechanisms underlying CLASP2-related HSC defects.