p38 Mitogen-Activated Protein Kinase in beryllium-induced dendritic cell activation.

Area of Science:

• Immunology
• Cell Biology
• Toxicology

Background:

• Dendritic cells (DCs) regulate immune responses to haptens, influencing DC maturation.
• The effect of beryllium (Be) on DC maturation and the involvement of the MAPK pathway are unknown.

Purpose of the Study:

• To investigate whether beryllium induces DC maturation and if this process involves the MAPK pathway.
• To evaluate the role of Be-induced DC activation in beryllium sensitization (BeS) and chronic beryllium disease (CBD).

Main Methods:

• Primary monocyte-derived DCs (moDCs) from healthy volunteers, BeS, and CBD subjects were stimulated with BeSO₄.
• Expression of CD40, p38MAPK phosphorylation, and IκB-α degradation were assessed.
• The effect of p38 MAPK inhibitor SB203580 on Be-stimulated responses was evaluated, including T cell proliferation and cytokine production (TNF-α, IFNγ).

Main Results:

• BeSO₄ significantly increased CD40 expression on HLA-DP Glu69+ moDCs.
• BeSO₄ induced p38MAPK phosphorylation and IκB-α degradation, indicating activation of p38MAPK and NF-κB pathways.
• p38MAPK and NF-κB activation were dependent on each other.
• In BeS and CBD subjects, SB203580 reduced Be-stimulated T cell proliferation and decreased TNF-α and IFNγ production.

Conclusions:

• Beryllium induces maturation of non-sensitized HLA-DP Glu69+ DCs.
• p38MAPK signaling is crucial for Be-stimulated DC activation and subsequent T cell responses in BeS and CBD.
• The MAPK pathway represents a potential therapeutic target for beryllium-induced granulomatous lung diseases.