ZIP8 exacerbates collagen-induced arthritis by increasing pathogenic T cell responses

Area of Science:

• Immunology
• Molecular Biology
• Autoimmune Diseases

Background:

• Zinc is crucial for immune cell function and its dysregulation is implicated in autoimmune diseases like rheumatoid arthritis (RA).
• The precise mechanisms of zinc regulation and its role in RA pathogenesis, particularly within immune cells, remain unclear.
• Zinc transporters are key regulators of intracellular zinc homeostasis, but their specific involvement in RA is under investigation.

Purpose of the Study:

• To investigate the role of zinc transporters in the pathogenesis of rheumatoid arthritis (RA).
• To determine the specific contribution of ZIP8 transporter in CD4+ T cell function and its impact on RA development.

Main Methods:

• Analysis of ZIP8 expression in CD4+ T cells infiltrating inflamed joints in a collagen-induced arthritis (CIA) model.
• Assessment of collagen-induced arthritis severity in mice with ZIP8-deficient CD4+ T cells.
• Evaluation of zinc influx, T cell receptor (TCR)-mediated signaling (NF-κB, MAPK), and T helper 17 (Th17) cell differentiation in ZIP8-deficient T cells.

Main Results:

• ZIP8 was found to be specifically upregulated in CD4+ T cells within inflamed joints.
• CD4+ T cell-specific ZIP8 deficiency completely abrogated collagen-induced arthritis in the mouse model.
• ZIP8 deficiency led to reduced zinc influx in effector T cells, impaired TCR-mediated signaling, and diminished Th17 cell differentiation.

Conclusions:

• ZIP8 transporter plays a critical role in CD4+ T cell function and is essential for RA pathogenesis.
• ZIP8-mediated zinc influx is necessary for optimal TCR signaling and Th17 cell differentiation in effector T cells.
• Targeting ZIP8 in CD4+ T cells presents a potential therapeutic strategy for inhibiting RA development and progression.