Substrate stiffness influences phenotype and function of human antigen-presenting dendritic cells

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• Dendritic cells (DCs) are crucial immune sentinels that migrate through diverse tissues.
• Tissue mechanical properties, like stiffness, change in conditions such as fibrosis and cancer.
• The influence of tissue stiffness on DC function remains largely unexplored.

Purpose of the Study:

• To investigate the impact of substrate stiffness on dendritic cell phenotype and function.
• To determine how mechanical cues from the microenvironment affect DC behavior.
• To understand the role of tissue stiffness in regulating immune responses.

Main Methods:

• Dendritic cells were cultured on polyacrylamide substrates with varying stiffness (2, 12, and 50 kPa).
• Phenotypic analysis included assessing C-type lectin, β2 integrin, CD83, and CCR7 expression.
• Functional assays measured antigen internalization and podosome formation.
• Migration responses were evaluated based on chemokine (CCR7) expression.

Main Results:

• Substrate stiffness differentially regulated C-type lectin expression on immature DCs (iDCs), affecting antigen internalization.
• Tissue stiffness influenced β2 integrin expression and podosome formation in iDCs.
• Mature DC expression of CD83 and CCR7 was modulated by substrate stiffness, impacting migration.

Conclusions:

• Dendritic cell phenotype and function are demonstrably affected by substrate stiffness.
• Tissue stiffness emerges as a critical environmental factor influencing immune cell behavior.
• These findings suggest that mechanical properties of the microenvironment play a significant role in modulating immune responses.