# HDAC3 knockdown inhibits ferroptosis via upregulating Nrf2 to alleviate renal interstitial fibrosis in lupus nephritis

## TL;DR

Reducing HDAC3 levels in lupus nephritis models improves kidney health by reducing fibrosis and oxidative stress through Nrf2 activation.

## Contribution

This study reveals that HDAC3 inhibition alleviates renal interstitial fibrosis in lupus nephritis via Nrf2 upregulation and reduced ferroptosis.

## Key findings

- HDAC3 levels are elevated in SLE and LN patients, with the highest levels in LN.
- HDAC3 knockdown reduces fibrosis, inflammation, and ferroptosis in LN mouse and cell models.
- HDAC3 inhibition disrupts Keap1-Nrf2 interaction, leading to Nrf2 activation.

## Abstract

Lupus nephritis (LN) is the most serious complication of SLE. Interstitial fibrosis is the dominant pathological change of renal injury in LN. Enhanced histone deacetylase 3 (HDAC3) positively correlates with renal interstitial fibrosis (RIF). Our study objective was to explore the accurate role and mechanism of HDAC3 in the RIF of LN.

To knock down HDAC3, Murphy Roths large (MRL)/wt and MRL/MpJ-Faslpr/J (MRL/lpr mice were injected with lentiviral short hairpin RNAs. Human renal proximal tubular epithelial cells (HK-2 cells) were treated with serum from patients with LN to establish an LN cell model. Renal histopathological change was assessed by H&E, Masson and Sirius red staining. Cell viability was determined using Cell Counting Kit-8 (CCK-8) kits. Inflammation cytokine determination was conducted employing ELISA assays. Protein expression was detected by western blot, and immunohistochemical and immunofluorescence staining. Gene densities were analysed by quantitative real-time PCR assays. Co-immunoprecipitation analysis validated the interactions of nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1).

HDAC3 levels were increased in the serum and kidney tissues of patients with SLE and LN, and the LN group posted the highest level. HDAC3 knockdown ameliorated RIF, oxidative stress, inflammation and ferroptosis in kidney tissues of MRL/lpr mice. Moreover, HDAC3 inhibition repressed the inflammatory and oxidative reactions, fibrosis and ferroptosis in LN-serum-induced HK-2 cells. Further, HDAC3 knockdown could inhibit the Keap1-Nrf2 interaction to trigger Nrf2 activation.

HDAC3 inhibition relieved RIF, oxidative stress, inflammation and ferroptosis by upregulating Nrf2 in the mice and cell models of LN.