Dendritic cell CD83 homotypic interactions regulate inflammation and promote mucosal homeostasis

Area of Science:

• Immunology
• Gastroenterology
• Cell Biology

Background:

• Dendritic cells (DCs) in the intestinal lamina propria are crucial for mucosal immunity.
• Dysfunctional DCs are linked to inflammatory bowel disease (IBD) through unknown mechanisms.

Purpose of the Study:

• To investigate the role of CD83, a DC surface protein, in modulating immune responses and preventing colitis.
• To elucidate the molecular mechanisms by which CD83 regulates DC function and intestinal inflammation.

Main Methods:

• Conditional knockout mice lacking CD83 in DCs were challenged with dextran sodium sulfate (DSS).
• In vitro studies assessed CD83 homotypic interactions, knockdown, and cytoplasmic truncation effects on DC activation.
• Mitogen-activated protein kinase (MAPK) pathway, specifically p38α phosphorylation, was analyzed.

Main Results:

• DC-specific CD83 knockout mice exhibited exacerbated colitis.
• Mucosal CD83 overexpression protected against colitis by inhibiting DC inflammatory responses.
• CD83 homotypic interaction, dependent on cell-cell contact and CD83 cytoplasmic domain, suppressed pro-inflammatory cytokine production.
• CD83 binding inhibited p38α phosphorylation in the MAPK pathway.

Conclusions:

• CD83 homotypic interactions are critical for regulating DC activation and function.
• These interactions inhibit pro-inflammatory signaling, thereby promoting mucosal homeostasis and preventing colitis.
• Targeting CD83-mediated DC regulation may offer a therapeutic strategy for IBD.