Hematopoietic stem cells contribute to lymphatic endothelium

Area of Science:

• Vascular biology
• Hematopoiesis
• Lymphatic system development

Background:

• The lymphatic system develops from venous vessels, but the role of circulating progenitors is unclear.
• Investigating the potential of hematopoietic stem cells (HSCs) to differentiate into lymphatic endothelial cells (LECs).

Purpose of the Study:

• To determine if HSCs can give rise to functional lymphatic endothelial cells.
• To explore the contribution of HSC-derived LECs to normal and tumor-associated lymphatic vasculature.

Main Methods:

• Transfer of marked HSCs into irradiated recipient mice.
• Analysis of parabiotic mice to identify circulating lymphatic progenitors.
• Transplantation of HSCs into Apc(Min/+) mice with intestinal tumors.

Main Results:

• Donor-derived LECs expressing Lyve-1 and VEGFR-3 were identified in multiple tissues post-HSC transplantation.
• HSC-derived LECs persisted long-term and contributed to lymphatic vessels, but not from myeloid progenitors.
• Functional circulating lymphatic progenitors were observed in parabiotic mice, and HSC-derived LECs were found in tumor lymphatics.

Conclusions:

• HSCs possess the potential to differentiate into LECs, contributing to both normal and tumor-associated lymphatic endothelium.
• This discovery opens avenues for novel therapeutic strategies involving HSC modification.
• Potential applications include targeting tumor metastasis and treating lymphatic system diseases.