Precisely Regulating M2 Subtype Macrophages for Renal Fibrosis Resolution.

Area of Science:

• Immunology
• Nephrology
• Cell Biology

Background:

• Macrophages are critical in kidney disease pathogenesis and fibrosis.
• M2-type macrophages have dual roles in inflammation and repair, with subtypes M2a and M2c exhibiting distinct functions.
• M2a macrophages can drive renal fibrosis via macrophage-to-myofibroblast transition (MMT), while M2c macrophages promote repair.

Purpose of the Study:

• To investigate the mechanisms of M2 macrophage polarization in renal fibrosis.
• To identify the role of transforming growth factor-beta (TGF-β) signaling intensity in M2a and M2c polarization.
• To develop a targeted nanotechnology approach to modulate macrophage polarization for renal fibrosis treatment.

Main Methods:

• Confirmation of M2a-derived MMT cells in renal fibrosis development.
• Analysis of TGF-β signaling intensity in differential M2a/M2c polarization.
• Application of targeted nanotechnology for co-delivery of an endoplasmic reticulum stress (ERS) inhibitor (Ceapin 7) and dexamethasone.
• Modulation of the ATF6/TGF-β/Smad3 signaling axis in macrophages.

Main Results:

• Excessive TGF-β stimulation promotes M2a to MMT, driving fibrosis.
• Moderate TGF-β stimulation favors M2c polarization, promoting tissue repair.
• Targeted nanotechnology effectively modulated macrophage polarization towards the M2c phenotype.
• The combined therapy suppressed excessive MMT polarization and promoted renal fibrosis resolution.

Conclusions:

• TGF-β signaling intensity is a critical determinant of M2 macrophage polarization in renal fibrosis.
• Targeted co-delivery of an ERS inhibitor and glucocorticoids offers a promising therapeutic strategy.
• This approach recalibrates macrophage phenotype, suppressing fibrosis and enhancing tissue repair in kidney disease.