Matrix viscoelasticity regulates dendritic cell migration and immune priming

Area of Science:

• Immunology
• Biophysics
• Cancer Biology

Background:

• The tumor microenvironment's mechanical properties influence immune surveillance.
• The specific role of matrix viscoelasticity in immune cell function is not well understood.

Purpose of the Study:

• To investigate how matrix relaxation affects dendritic cell (DC) behavior.
• To determine the impact of matrix viscoelasticity on immune cell interactions and anti-tumor immunity.

Main Methods:

• Utilized a collagen system with tunable viscoelasticity to study DC behavior.
• Assessed DC migration, T cell priming, activation, proliferation, and tumor killing in varying matrix stiffness.
• Investigated the effects of prolonged confinement in elastic matrices and analyzed chromatin accessibility.
• Examined patient-derived ependymoma samples to confirm findings in a clinical context.

Main Results:

• Elastic matrices impaired DC migration by limiting actomyosin-driven collagen remodeling.
• Reduced DC migration led to fewer DC-T cell encounters, weakening T cell priming, activation, proliferation, and tumor killing.
• Blocking DC migration mimicked the impaired T cell priming observed in elastic matrices.
• Prolonged confinement in elastic matrices induced a mechanomemory state in DCs, reducing motility even in viscoelastic environments.
• Altered chromatin accessibility was observed in DCs confined to elastic matrices.

Conclusions:

• Matrix viscoelasticity significantly influences dendritic cell behavior and anti-tumor immune responses.
• Viscoelasticity acts as a barrier to effective anti-tumor immunity.
• These findings have implications for developing novel therapeutic interventions targeting the tumor microenvironment.