A bioengineered lymphatic vessel model for studying lymphatic endothelial cell-cell junction and barrier function.

Area of Science:

• Biomedical Engineering
• Cell Biology
• Physiology

Background:

• Lymphatic vessels (LVs) are vital for fluid homeostasis, and their dysfunction leads to diseases like lymphedema.
• Lymphatic barrier function is a key regulator of lymphatic drainage, necessitating effective experimental models for study.

Purpose of the Study:

• To develop and utilize a lymphatic vessel-on-chip (LV-on-chip) model to investigate lymphatic barrier function.
• To identify molecular regulators of lymphatic endothelial cell (LEC) junction integrity and barrier function.

Main Methods:

• Fabrication of a microfluidic device with a hollow microchannel embedded in 3D hydrogel to create an engineered LV.
• Seeding human lymphatic endothelial cells (LECs) within the microchannel and applying luminal flow to form a 3D conduit structure.
• Assessing lymphatic barrier function by measuring dextran permeability and evaluating the role of fibronectin and integrin α5.

Main Results:

• LECs formed tighter junctions in the presence of fibronectin compared to collagen 1 alone.
• Fibronectin-mediated tightening of LEC junctions was dependent on integrin α5 activation.
• Inhibition of integrin α5 reversed the barrier-tightening effect, and integrin α5 activation alone enhanced barrier function.

Conclusions:

• The LV-on-chip model successfully mimics in vivo lymphatic vessel structure and function.
• Integrin α5 is identified as a critical regulator of lymphatic barrier function, influencing LEC junction permeability.
• This platform offers a valuable tool for studying lymphatic physiology and disease mechanisms under various conditions.