CCR7 and IRF4-dependent dendritic cells regulate lymphatic collecting vessel permeability

Area of Science:

• Immunology
• Vascular Biology
• Cell Biology

Background:

• Lymphatic collecting vessels are crucial for immune surveillance, directing lymph and immune cells to lymph nodes (LNs).
• Previous infections can cause lymphatic hyperpermeability, impairing immune cell transport and antigen presentation.
• The molecular mechanisms regulating lymphatic vessel permeability remain largely unknown.

Purpose of the Study:

• To investigate the molecular signals controlling lymphatic collecting vessel permeability.
• To elucidate the role of CCR7 in lymphatic vessel function and fibrosis.
• To identify specific immune cell subsets involved in lymphatic vessel regulation.

Main Methods:

• Analysis of lymphatic collecting vessel permeability and fibrosis in Ccr7-/- mice.
• Investigating the effect of CCR7 reexpression in dendritic cells (DCs).
• Utilizing conditional gene ablation (Cd11c-Cre Irf4fl/fl mice) to study IRF4+ DCs.

Main Results:

• CCR7 deficiency leads to chronic lymphatic collecting vessel hyperpermeability and subsequent fibrosis.
• Reexpression of CCR7 in DCs reverses lymphatic fibrosis.
• Ablation of IRF4+ DCs causes lymphatic collecting vessel hyperpermeability and fibrosis, highlighting their constitutive interaction with lymphatics.

Conclusions:

• CCR7 plays a critical role in maintaining lymphatic collecting vessel integrity and preventing fibrosis.
• IRF4-dependent dendritic cells are key regulators of lymphatic vessel permeability and fibrosis.
• Targeting CCR7 and IRF4+ DCs may offer therapeutic strategies for immune dysfunction associated with lymphatic abnormalities.