# IL‑1 receptor antagonism attenuates renal fibrosis via RNF182‑driven MFN2 destabilization and mitochondrial dysfunction

## TL;DR

Blocking IL-1 signaling reduces kidney fibrosis by stabilizing mitochondria through a newly discovered pathway involving RNF182 and MFN2.

## Contribution

The study identifies a novel IL-1R/RNF182/MFN2 pathway linking inflammation to mitochondrial dysfunction and fibrosis in kidney disease.

## Key findings

- rhIL-1Ra reduces renal fibrosis, inflammation, and functional impairment in mouse models of kidney injury.
- RNF182 mediates MFN2 ubiquitination and degradation, leading to mitochondrial dysfunction.
- Inhibiting RNF182 stabilizes MFN2, preserves mitochondrial function, and reduces oxidative stress.

## Abstract

Renal fibrosis is a major driver of chronic kidney disease (CKD) progression, yet targeted therapies remain limited due to incomplete understanding of key molecular mechanisms. While IL-1-mediated inflammation and mitochondrial dysfunction are recognized contributors, the precise links between IL-1 signaling, fibrosis, and mitochondrial homeostasis are unclear. Here, we investigated the therapeutic effects of recombinant human IL-1 receptor antagonist (rhIL-1Ra) in both acute (UUO) and chronic (5/6Nx) mouse models of kidney injury, as well as in vitro TGF-β1-stimulated kidney cells. rhIL-1Ra significantly attenuated renal fibrosis, inflammation, and functional impairment in vivo. Mechanistically, rhIL-1Ra suppressed TGF-β1-induced expression of the E3 ubiquitin ligase RNF182, which we show mediates MFN2 ubiquitination and degradation, leading to mitochondrial dysfunction. Inhibition of RNF182 by rhIL-1Ra stabilized MFN2, preserved mitochondrial respiration and ATP production, and reduced oxidative stress. Rescue experiments confirmed the centrality of the RNF182-MFN2 axis in fibrotic and mitochondrial injury. Our findings reveal a novel IL-1R/RNF182/MFN2 pathway linking inflammation to mitochondrial and fibrotic pathology, supporting RNF182 as a promising target and rhIL-1Ra as a potential therapy for CKD.