A20 expression in dendritic cells protects mice from LPS-induced mortality

Area of Science:

• Immunology
• Cell Biology

Background:

• Dendritic cells (DCs) maintain immune homeostasis and regulate immune responses during infection.
• The deubiquitinase A20 normally inhibits NF-κB activation, preventing DC hyperactivation.
• The role of DC-specific A20 in pathological conditions remained unclear.

Purpose of the Study:

• To investigate the function of DC-specific A20 in pathological conditions, particularly in response to lipopolysaccharide (LPS).

Main Methods:

• Utilized CD11c-Cre A20(fl/fl) mice with DC-specific A20 deletion.
• Administered low-dose LPS to mice and monitored survival and serum cytokine levels.
• Analyzed NF-κB and ERK-NFATc3 pathway activation in A20-deficient DCs.
• Investigated the role of T cells and intestinal flora in LPS tolerance.

Main Results:

• DC-specific A20 deletion led to rapid mortality upon LPS injection, unlike controls.
• LPS-challenged CD11c-Cre A20(fl/fl) mice exhibited elevated serum IL-2, IL-10, IL-12, IFN-γ, and TNF.
• A20-deficient DCs showed enhanced NF-κB and ERK-NFATc3 activation, increasing IL-2, IL-12, and TNF production.
• Targeted ERK inhibition reduced IL-2 production in A20-deficient DCs.
• A20-deficient DCs failed to induce LPS tolerance, independent of T cells and gut microbiota.

Conclusions:

• DC-specific A20 is essential for preserving immune homeostasis under steady-state conditions.
• DC-specific A20 plays a critical role in establishing LPS tolerance.
• Loss of DC-specific A20 leads to hyperinflammation and mortality upon LPS challenge.