USP19 facilitates CSE-induced cell damage and ferroptosis in chronic obstructive pulmonary disease by deubiquitinating HDAC6 to drive PRDX6 deacetylation.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a disease characterized by airflow obstruction. Peroxiredoxin 6 (PRDX6) is vital in antioxidant defense and phospholipid metabolism, and linked to disease occurrence and progression. Ubiquitin-specific protease 19 (USP19), a deubiquitinating enzyme involved in protein stability regulation, has been implicated in inflammatory diseases and cellular stress responses, yet its role in COPD remains largely unknown. The objective of this study is to investigate the impact and the underlying mechanism of PRDX6 on cigarette smoke extract (CSE)-induced cell injury and ferroptosis, with a focus on the regulatory roles of USP19 and histone deacetylase 6 (HDAC6). METHODS: The expression levels of the genes were detected by reverse transcription-quantitative polymerase chain reaction (qRT-PCR) and western blot. The Cell counting kit-8 (CCK-8) was utilized to assess cell viability. Cell apoptosis was detected by flow cytometry. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected using the enzyme-linked immunosorbent assay (ELISA). The iron ion (Fe2+), reactive oxygen species (ROS), and glutathione (GSH) kits were used to evaluate the ferroptosis index. The Biological General Repository for Interaction Datasets (BioGRID), Hitpredict database, and Ubibrowser database were used to predict protein interactions. Protein modifications and protein-protein interactions were verified using co-immunoprecipitation (CoIP). The treatment with cycloheximide (CHX) was used to verify protein stability. The rat COPD model was used for in vivo validation. Hematoxylin-eosin (HE), Masson's trichrome (Masson) and Periodic Acid-Schiff (PAS) staining were utilized for the assessment of lung injury. Immunohistochemistry (IHC) analysis was conducted to assess the levels of PRDX6 present in rat lung tissue. RESULTS: In CSE-induced 16HBE cells, upregulating PRDX6 expression mitigated the decline in cellular viability, prevented apoptosis, suppressed inflammatory reactions, and halted ferroptosis. HDAC6 facilitated CSE-induced cellular damage and ferroptosis by mediating the deacetylation modification of PRDX6. USP19 enhanced the stability of HDAC6 by deubiquitination, thereby exacerbating CSE-induced cellular damage and ferroptosis. The elevated levels of PRDX6 mitigated cellular damage and ferroptosis in the rat COPD models. CONCLUSIONS: USP19 modulates PRDX6 expression by deubiquitinating HDAC6, thereby promoting CSE-induced cellular damage and ferroptosis. This deepens our understanding on COPD pathogenic mechanism and may offer a new perspective for COPD treatment.