Pexophagy-driven redox imbalance promotes virus-induced ferroptosis
Peroxisomes are critical organelles that maintain cellular redox homeostasis. Many viruses induce oxidative stress and degrade peroxisomes, but the mechanisms and consequences remain unclear. In this study, we systematically investigate how virus-induced pexophagy regulates peroxisome homeostasis. Using Newcastle disease virus (NDV) as a model, we demonstrate that NDV infection triggers excessive ROS production, activating the phosphorylation and peroxisomal localization of Ataxia-telangiectasia mutated (ATM). Activated ATM promotes the interaction between the peroxisomal receptor PEX5 and the autophagy receptor p62, driving pexophagy. Pexophagy-mediated peroxisome degradation leads to excess active iron and ROS accumulation, contributing to NDV-induced ferroptosis. Notably, this mechanism is shared by other viruses, such as vesicular stomatitis virus (VSV) and H9N2 avian influenza virus (IAV). Our study provides new insights into how virus-induced pexophagy disrupts redox homeostasis to promote ferroptosis, highlighting a novel link between viral infection, peroxisome degradation, and programmed cell death. Overall design: RNA-seq was conducted to compare gene expression profiles at multiple NDV infection time points (6, 12, 18, 24 hpi.) against the time-matched uninfected controls at each time point. Each group of samples included three replicates. Total RNA was extracted using TRIzol® Reagent following the manufacturer's protocol. RNA quality was assessed via 5300 Bioanalyser and NanoDrop ND-2000, with only high-quality RNA (OD260/280=1.8~2.2, OD260/230=2.0, RQN=6.5, 28S:18S=1.0, >1µg) used for sequencing library construction. RNA-seq libraries were prepared at Shanghai Majorbio Bio-pharm Biotechnology Co., Ltd. using the Illumina® Stranded mRNA Prep, Ligation protocol. PolyA-selected mRNA was fragmented, reverse-transcribed into cDNA, end-repaired, and adapter-ligated, followed by PCR amplification and size selection (300 bp). Libraries were sequenced on the NovaSeq X Plus platform. Raw reads were quality-controlled by fastp and aligned to the reference genome via HISAT2. Mapped reads were assembled using StringTie. Differentially expressed genes (DEGs) were identified using DESeq2 or DEGseq, with thresholds of |log2FC|=1 and FDR<0.05 (DESeq2) or FDR<0.001 (DEGseq). Functional enrichment analysis was also performed to interpret biological significance.