Affiliation:
1. Fudan University
2. Ministry of Public Health, Fudan University
3. Yuhuan People's Hospital
Abstract
Abstract
Background.
Systemic sclerosis (SSc), with unclear pathophysiology, is a paradigmatic rheumatic disease of immunity dysfunction driven multi-organ inflammation and ultimate fibrosis. Pathogenesis breakthroughs are urgently needed for available treatments halting its unremitting stiffness. This study aims to investigate whether ferroptosis can regulate the progressive SSc fibrosis.
Methods
In vivo, bleomycin (BLM) -induced mice model were subjected to ferroptosis detection using western blotting, malondialdehyde (MDA) and glutathione (GSH) assays. Pharmacological inhibitor of the acyl-CoA synthetase long-chain family member 4 (ACSL4) was utilized to explore its potential therapeutic effects for fibrosis, from histological, biochemical, proteomic and molecular analyses. In vitro, bone marrow-derived macrophages (BMDM) was activated into inflammatory phenotype and then evaluated the relationship between activation level and ferroptosis sensitivity in lipopolysaccharide(LPS)incubation with gradient concentration. The potential calpain/ACSL4 axis was analyzed after calpain knockdown or over-expression in Raw264.7.
Results.
A wild rage of tissue ferroptosis was present in SSc mice with enhanced ACSL4 expression, while ACSL4 inhibition effectively halted fibrosis progressing and provides protection from inflammatory milieu. Meanwhile, a positive regulation relationship between LPS-induced macrophage activity and ferroptosis sensitivity can be observed. After calpain knockdown, both inflammatory macrophage ferroptosis sensitivity and ACSL4 expression decreased, while its over-expression renders ACSL4-envoking condition. Also, calpain pharmacological inhibition reduced both ferroptosis and fibrosis aptitude in mice.
Conclusions.
ACSL4 induces inflammatory macrophage ferroptosis to aggravate fibrosis progressing. ACSL4 and its up-regulators of calpains may be potential therapeutic targets for BLM model of SSc.
Publisher
Research Square Platform LLC