Thrombin regulates the function of human blood dendritic cells

Area of Science:

• Immunology
• Hematology
• Cell Biology

Background:

• Thrombin, a key coagulation enzyme, activates various immune cells via protease-activated receptors (PARs).
• The role of thrombin in regulating dendritic cell (DC) function, crucial for immune responses, remains largely unexplored.

Purpose of the Study:

• To investigate the effects of thrombin on blood dendritic cells (DCs) and their functional responses.

Main Methods:

• Isolation of plasmacytoid DC (PDC) and myeloid DC (MDC) from peripheral blood mononuclear cells (PBMC).
• Stimulation of DCs with thrombin and assessment of cytokine release (MCP-1, IL-10, IL-12) and receptor expression (PAR-1).
• Evaluation of thrombin's effect on monocyte-derived DC (MoDC) and the impact of anti-PAR-1 antibodies and hirudin.

Main Results:

• Blood DCs (PDC and MDC) expressed PAR-1 and released MCP-1, IL-10, and IL-12 upon thrombin stimulation.
• In vitro-differentiated MoDCs lacked PAR-1 expression and were unresponsive to thrombin.
• Thrombin stimulation increased HLA-DR and CD86 expression on blood DCs, enhancing their ability to induce allogeneic T cell proliferation.

Conclusions:

• Thrombin modulates the function of blood DCs through PAR-1 signaling.
• These findings highlight a novel role for thrombin in regulating innate and adaptive immune responses via dendritic cells.