Wnt/β-Catenin-Promoted Macrophage Alternative Activation Contributes to Kidney Fibrosis

Area of Science:

• Cell Biology
• Renal Physiology
• Immunology

Background:

• The Wnt/β-catenin pathway is vital for development but implicated in kidney fibrosis.
• Mechanisms linking Wnt/β-catenin to kidney fibrosis, particularly via macrophage activation, are not fully understood.

Purpose of the Study:

• To investigate the role of Wnt/β-catenin signaling in regulating macrophage activation.
• To determine the contribution of Wnt/β-catenin-mediated macrophage activation to kidney fibrosis.

Main Methods:

• In vitro studies using Wnt3a treatment and Wnt/β-catenin inhibition on macrophages.
• In vivo studies using a mouse model with induced deletion of β-catenin in macrophages after unilateral ureter obstruction.

Main Results:

• Wnt3a treatment enhanced IL-4/TGFβ1-induced M2 macrophage polarization and STAT3 activation in vitro.
• Wnt/β-catenin inhibition blocked these IL-4/TGFβ1-induced effects.
• Macrophage-specific β-catenin deletion attenuated kidney fibrosis, macrophage accumulation, and M2 polarization in vivo.

Conclusions:

• Wnt/β-catenin signaling activation promotes kidney fibrosis.
• This promotion occurs through the stimulation of macrophage M2 polarization.
• Targeting Wnt/β-catenin signaling in macrophages may offer a therapeutic strategy for kidney fibrosis.