Peroxiredoxin 3 Inhibits Acetaminophen-Induced Liver Pyroptosis Through the Regulation of Mitochondrial ROS

Pyroptosis is a newly discovered form of cell death. Peroxiredoxin 3 (PRX3) plays a crucial role in scavenging reactive oxygen species (ROS), but its hepatoprotective capacity in acetaminophen (APAP)-induced liver disease remains unclear. The aim of this study was to assess the role of PRX3 in the regulation of pyroptosis during APAP-mediated hepatotoxicity. We demonstrated that pyroptosis occurs in APAP-induced liver injury accompanied by intense oxidative stress and inflammation, and liver specific PRX3 silencing aggravated the initiation of pyroptosis and liver injury after APAP intervention. Notably, excessive mitochondrial ROS (mtROS) was observed to trigger pyroptosis by activating the NLRP3 inflammasome, which was ameliorated by Mito-TEMPO treatment, indicating that the anti-pyroptotic role of PRX3 relies on its powerful ability to regulate mtROS. Overall, PRX3 regulates NLRP3-dependent pyroptosis in APAP-induced liver injury by targeting mitochondrial oxidative stress.

Up-regulation of peroxiredoxin 3 by high-risk human papillomavirus in cervical cancer cells

IntroductionPeroxiredoxin 3 (PRX3) is a member of PRX family with antioxidant functions by scavenging hydrogen peroxide. Since the development of cervical cancer is causally linked to high-risk human papillomavirus (HPV) that induces oxidative stress, we conducted the present study to investigate the response of PRX3 to high-risk HPV infection.Material and methodsThis study included fifty-six patients with invasive squamous cervical cancer and sixty control patients with hysteromyoma. Enzyme-linked immunosorbent assay was performed to detect cervical oxidative stress and serum PRX3. The expression of PRX3 and oncoprotein E6 of HPV16 or HPV18 was examined in cervical cancer tissues by immunohistochemistry. Western Blot was applied to detect the expression of PRX3 and E6 in cervical cancer cell lines including CaSki, HeLa, and C33A.ResultsPatients with cervical cancer showed higher serum PRX3 than control patients with hysteromyoma. Levels of oxidative markers in cervical cancer tissues were elevated as compared to normal cervical epithelia. PRX3 expression was upregulated in cervical cancer tissues and the upregulation was positively associated with the expression of E6 of HPV16 or HPV18. The association was confirmed in HPV-containing cervical cancer cell lines including CaSki and HeLa.ConclusionsOur results indicated a positive response of PRX3 to HPV-induced oxidative stress. Serum PRX3 might be a potential indicator of active amplification of high-risk HPV in cervical cancer cells.

Unique Cellular and Biochemical Features of Human Mitochondrial Peroxiredoxin 3 Establish the Molecular Basis for Its Specific Reaction with Thiostrepton

A central hallmark of tumorigenesis is metabolic alterations that increase mitochondrial reactive oxygen species (mROS). In response, cancer cells upregulate their antioxidant capacity and redox-responsive signaling pathways. A promising chemotherapeutic approach is to increase ROS to levels incompatible with tumor cell survival. Mitochondrial peroxiredoxin 3 (PRX3) plays a significant role in detoxifying hydrogen peroxide (H2O2). PRX3 is a molecular target of thiostrepton (TS), a natural product and FDA-approved antibiotic. TS inactivates PRX3 by covalently adducting its two catalytic cysteine residues and crosslinking the homodimer. Using cellular models of malignant mesothelioma, we show here that PRX3 expression and mROS levels in cells correlate with sensitivity to TS and that TS reacts selectively with PRX3 relative to other PRX isoforms. Using recombinant PRXs 1–5, we demonstrate that TS preferentially reacts with a reduced thiolate in the PRX3 dimer at mitochondrial pH. We also show that partially oxidized PRX3 fully dissociates to dimers, while partially oxidized PRX1 and PRX2 remain largely decameric. The ability of TS to react with engineered dimers of PRX1 and PRX2 at mitochondrial pH, but inefficiently with wild-type decameric protein at cytoplasmic pH, supports a novel mechanism of action and explains the specificity of TS for PRX3. Thus, the unique structure and propensity of PRX3 to form dimers contribute to its increased sensitivity to TS-mediated inactivation, making PRX3 a promising target for prooxidant cancer therapy.