Dietary exposure to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) induces oxidative damage promoting cell apoptosis primarily via mitochondrial pathway in the hepatopancreas of carp, Cyprinus carpio

Size-dependent ecotoxicological impacts of tire wear particles on zebrafish physiology and gut microbiota: Implications for aquatic ecosystem health

The ecological impact of tire wear particles (TWP), a significant source of microplastics pollution, is increasingly concerning, especially given their potential effects on the health of aquatic ecosystems. This study investigates the size-dependent ecotoxicological responses of zebrafish (Danio rerio) to TWP exposure, focusing on physiological, metabolic, and microbial community impacts over a 15-day exposure period followed by a 15-day excretion period. Through integrated analysis of gut microbiome composition, liver transcriptomics, and host physiological markers, we found that smaller TWP particles (< 120 μm) induced oxidative stress, evidenced by increased SOD and MDA levels, and inhibited growth by reducing body mass and gut length. In contrast, larger TWP particles (250-380 μm) caused more substantial disruptions in lipid and xenobiotic metabolic pathways, as shown by significant downregulation of key metabolic genes (acads, cpt2_1, hadhaa), and alterations in the gut microbiome, including the enrichment of pathogenic genera, such as Enterococcus and Fusobacterium, while depleting beneficial microbes like Acinetobacter and Methyloversatilis. These microbiome shifts led to a more complex and potentially pathogenic gut microbiome. Notably, zebrafish displayed adaptive resilience during the excretion period, with significant recovery in body mass and microbial composition, emphasizing the adaptive capacity of aquatic organisms to pollutants. Our findings underscore the broader ecological risks posed by TWP, the pivotal role of gut microbiota in host resilience to pollutants, and the need for comprehensive management strategies addressing emerging contaminants in aquatic ecosystems.

Polybrominated biphenyls induce liver injury by disrupting the KEAP1/Nrf2/SLC7A11 axis leading to impaired GSH synthesis and ferroptosis in hepatocytes

Polybrominated biphenyls (PBBs) are persistent organic pollutants (POPs) widespread in the environment, presenting significant health hazards due to their bioaccumulation, particularly in liver. Ferroptosis, an iron-dependent form of cell death, has not been previously linked to PBBs-induced hepatotoxicity. This study investigated whether PBBs induce hepatotoxicity through ferroptosis and the toxicological mechanism using mice and THLE-2 cells models exposed to PBB mixture (BP-6). Histopathological and biochemical analyses revealed that BP-6 exposure-induced hepatic injury, oxidative stress, and inflammatory response in mice. BP-6 exposure induced a significant increase in Fe2+ content and a decrease in FTH1, SLC7A11 and GPX4 protein expression in hepatocytes, resulting in severe lipid peroxide accumulation and GSH depletion. Ferroptosis inhibitors, Fer-1 and DFO, reversed the iron metabolism disruption caused by BP-6, underscoring the critical role of ferroptosis in BP-6-induced liver injury. Mechanistically, BP-6 exposure impaired GSH synthesis by preventing Nrf2 nuclear translocation and Slc7a11 transcription through upregulating KEAP1 levels. Keap1 knockdown or Slc7a11 overexpression reversed BP-6-induced lipid peroxide accumulation and GSH depletion, confirming the involvement of ferroptosis in BP-6-induced hepatotoxicity. In addition, curcumin, a natural Nrf2 agonist, significantly alleviated BP-6-induced ferroptosis and liver injury in vitro and in vivo by restoring SLC7A11 protein expression and GSH synthesis. These findings elucidate the toxicological mechanism of PBBs and suggest potential therapeutic strategies to counteract PBBs exposure.

2,2',4,4'-Tetrabromodiphenyl ether exposure disrupts blood-testis barrier integrity through CMA-mediated ferroptosis

2,2',4,4'-Tetrabromodiphenyl ether (PBDE-47), being the most prevalent congener of polybrominated diphenyl ethers (PBDEs), has been found to accumulate greatly in the environment and induce spermatogenesis dysfunction. However, the specific underlying factors and mechanisms have not been elucidated. Herein, male Sprague-Dawley (SD) rats were exposed to corn oil, 10 mg/kg body weight (bw) PBDE-47 or 20 mg/kg bw PBDE-47 by gavage for 30 days. PBDE-47 exposure led to blood-testis barrier (BTB) integrity disruption and aberrant spermatogenesis. Given that Sertoli cells are the main toxicant target, to explore the potential mechanism involved, we performed RNA sequencing (RNA-seq) in Sertoli cells, and the differentially expressed genes were shown to be enriched in ferroptosis and lysosomal pathways. We subsequently demonstrated that ferroptosis was obviously increased in testes and Sertoli cells upon exposure to PBDE-47, and the junctional function of Sertoli cells was restored after treatment with the ferroptosis inhibitor ferrostatin-1. Since glutathione peroxidase 4 (GPX4) was dramatically reduced in PBDE-47-exposed testes and Sertoli cells and considering the RNA-sequencing results, we examined the activity of chaperone-mediated autophagy (CMA) and verified that the expression of LAMP2a and HSC70 was upregulated significantly after PBDE-47 exposure. Notably, Lamp2a knockdown not only inhibited ferroptosis by suppressing GPX4 degradation but also restored the impaired junctional function induced by PBDE-47. These collective findings strongly indicate that PBDE-47 induces Sertoli cell ferroptosis through CMA-mediated GPX4 degradation, resulting in decreased BTB-associated protein expression and eventually leading to BTB integrity disruption and spermatogenesis dysfunction.

Long-term dietary exposure to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) reduced feeding in common carp (Cyprinus carpio): Via the JAK-STAT signaling pathway

Polybrominated diphenyl ethers (PBDEs) are widely present in water ecosystems where they pose a significant threat to aquatic life, but our knowledge about how PBDEs affect feeding is limited. Therefore, this study explored the effects of continuous dietary exposure to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) (40 and 4000 ng/g) on the feeding in common carp (Cyprinus carpio) and the underlying mechanism. BDE-47 significantly decreased the food intake of carp. Transcriptome analysis of brain tissue showed that BDE-47 mainly affected the nervous, immune, and endocrine systems. Further examination of the expression levels of appetite factors in the brain revealed that BDE-47 caused dysregulation of appetite factors expressions such as agrp, pomc, cart, etc. In addition, the JAK-STAT signaling pathway was activated under BDE-47 exposure. It can be concluded from these findings that BDE-47 activated the JAK-STAT signaling pathway, causing imbalanced expression of appetite factors, leading to disordered feeding behavior and decreased food intake in carp. These results provide an important reference for a more comprehensive understanding of the hazards posed by BDE-47 on animal feeding and the associated mechanisms.