FAM46B inhibits CS-induced oxidative stress and ferroptosis in bronchial epithelial cells via KLHL24.

Background: Chronic obstructive pulmonary disease (COPD), mainly caused by cigarette smoke (CS), is a global health concern. Ferroptosis is recognized as a key driver of COPD progression, yet its underlying mechanisms are unclear. This study aimed to identify crucial genes involved in COPD and elucidate their functional roles in COPD via bioinformatics and experiments.

Methods: Key COPD-associated genes were identified through bioinformatics and machine learning. Transcriptomic sequencing revealed downstream genes of FAM46B. BEAS-2B cells were treated with CS extract (CSE), and transfected with lentiviral overexpression of FAM46B and KLHL24, siRNA knockdown of KLHL24, and the ferroptosis inhibitor Ferrostatin-1 (Fer-1). We assessed cell viability, apoptosis, inflammatory cytokines (IL-1β, TNF-α), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), intracellular iron, mitochondrial membrane potential, and ferroptosis markers (GPX4, PTGS2, NCOA4). In a mouse model (C57BL/6), we evaluated tissue pathology, inflammatory cytokines, oxidative stress, and ferroptosis markers.

Results: FAM46B overexpression and KLHL24 knockdown significantly increased cell viability, reduced apoptosis, and decreased IL-1β and TNF-α levels in CSE-treated BEAS-2B cells. These interventions also alleviated oxidative stress and MDA levels, enhanced GSH levels, reduced intracellular iron accumulation and mitochondrial membrane potential depolarization, and ameliorated mitochondrial structural damage in CSE-induced BEAS-2B cells. Furthermore, GPX4 expression was upregulated, while PTGS2 and NCOA4 expression were downregulated. KLHL24 overexpression counteracted the protective effects of FAM46B. Fer-1 treatment partially reversed the effects of dual FAM46B and KLHL24 overexpression. In vivo studies confirmed the suppressive effect of FAM46B on oxidative stress and ferroptosis via KLHL24.

Conclusion: The FAM46B-KLHL24 axis is crucial in regulating oxidative stress and ferroptosis in CS-induced COPD, providing potential therapeutic targets for disease management.