The antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), widely used in tire rubber production, and its oxidative transformation product 6PPD-quinone (6PPD-Q), have become emerging urban environmental pollutants distributed worldwide, which can cause respiratory exposure in humans through atmospheric particulate matter and aerosols, potentially damaging the respiratory system; moreover, studies have suggested that such exposure is associated with the occurrence and development of lung cancer. In this study, a multidimensional computational research framework integrating network toxicology, weighted gene co-expression network analysis (WGCNA), machine learning, molecular docking, and molecular dynamics simulation was constructed to systematically decipher the dynamic molecular mechanisms by which 6PPD regulates lung cancer progression. Through cross-screening of multiple databases, 35 common interaction targets between 6PPD and lung cancer were identified, and candidate hub genes were screened out. GO and KEGG analyses showed that the targets were enriched in cancer-related pathways such as chemical carcinogenesis-reactive oxygen species and VEGF, suggesting that oxidative stress may be the core regulatory direction. The Ridge machine learning prediction model achieved an accuracy of 1.000 (AUC = 0.985) in the training set, and also exhibited good generalization ability in two independent validation datasets, and further screened out CA4, CDC25C, and NQO1 as core biomarkers; all three were significantly overexpressed in lung cancer tissues and exhibited good diagnostic efficacy for lung cancer. Molecular docking and 100 ns molecular dynamics simulation showed that 6PPD possessed strong spontaneous binding ability toward NOX4 (−8.0 kcal/mol), NQO1 (−7.9 kcal/mol), KDR, CA4, and CDC25C, and the complexes formed with the core targets remained generally stable throughout the simulations, suggesting that 6PPD can persistently bind to target proteins through stable intermolecular interactions. Trajectory hierarchical clustering analysis further showed that the conformational dynamic characteristics of each complex differed; among them, the KDR conformation was the most stable, whereas NQO1 and CA4 showed higher conformational diversity. In summary, the results of this study suggest that 6PPD may participate in oxidative stress pathway activation, DNA damage, cell cycle regulation, and tumor angiogenesis through multi-target synergistic effects, and be associated with lung cancer progression; this provides a computational pathway for deciphering the carcinogenic molecular mechanisms of environmental pollutants and assessing respiratory carcinogenic risk, and the core targets may provide candidate molecular markers for early warning and intervention of lung cancer.
Micro- and nanoplastics (MNPs) are widely distributed and persistent in the environment. They can enter the body through ingestion, inhalation, and dermal contact, and their potential effects on female reproductive health have drawn increasing attention. Oocytes are central to female reproductive function. However, the mechanisms underlying MNP toxicity to oocytes, as well as their intergenerational and transgenerational effects, remain poorly understood. This review searched databases such as PubMed and Web of Science. By integrating evidence from diverse animal models and human samples, it summarizes the potential effects of MNPs on oocytes and the related molecular mechanisms. The findings indicate that MNPs may impair oocyte development via oxidative stress, inflammation, endoplasmic reticulum stress, endocrine disruption, and epigenetic modifications. These processes are associated with changes in the Wnt/β-catenin, NOD-like receptor family pyrin domain containing 3 (NLRP3)/caspase-1, Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB), and protein kinase R-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2 alpha (eIF2α) signaling pathways, and are linked to mitochondrial dysfunction, apoptosis, meiotic defects, chromosomal abnormalities, and impaired oocyte maturation. Animal studies further suggest that maternal exposure to MNPs may impair offspring development and reproductive function. However, evidence for true transgenerational effects remains limited. Notably, most existing evidence comes from animal studies, many of which used standardized polystyrene (PS) particles. Although MNPs have been detected in human biological samples, their actual effects on human reproductive health remain to be clarified.
Acetaminophen (APAP) overdose is a major cause of acute liver injury that is primarily driven by oxidative stress and mitochondrial dysfunction resulting from excessive N-acetyl-p-benzoquinone imine formation. Although the transcription factor C/EBP homologous protein (CHOP) is markedly increased during APAP-induced liver injury (AILI), its functional role in hepatocellular stress responses remains unclear. In this study, we examined the role of CHOP in hepatic redox regulation during AILI and its relationship with Fos. Using wild-type and Chop-null mice, we found that CHOP deficiency significantly exacerbated AILI with elevated serum alanine aminotransferase levels and extensive necrosis. At the molecular level, CHOP deficiency led to impaired GSH-dependent antioxidant pathway induction and decreased hepatic reduced glutathione (GSH). Notably, APAP-induced Fos expression was strongly CHOP-dependent, and CHOP and FOS showed partial spatial overlap at the boundary between injured and preserved liver parenchyma. Promoter-reporter analysis and ChIP-qPCR further supported CHOP-dependent transcriptional regulation of Fos. These findings support a CHOP–FOS-associated antioxidant response that contributes to hepatic redox homeostasis by promoting GSH-dependent antioxidant defenses, thereby supporting hepatocyte adaptation during AILI.
Exposure to low-level artificial-light at night (L-ALAN) during pregnancy is increasingly common and disrupt melatonin (MT) synthesis. MT maintains circadian rhythm homeostasis and placental/decidual functions. This study aimed to investigate the effects of prenatal L-ALAN exposure and MT intervention on maternal–fetal outcomes and underlying mechanisms. Pregnant C57BL/6 J mice were exposed to L-ALAN (2 lx during night) with or without MT supplementation (10 mg/kg/day, intragastrically) and assessed at embryonic day 16.5 or after natural delivery. Maternal serum and placental MT levels, and related maternal–fetal outcomes were evaluated. Morphological, circadian-omics, and RT-qPCR analyses were conducted to evaluate structural and functional changes in the maternal-placenta-decidual-fetal tissues. Circadian rhythmicity of core-circadian-clock-genes was evaluated using Jonckheere-Terpstra-Kendall (JTK)-CYCLE analysis. L-ALAN reduced nocturnal maternal serum and placental MT peaks, gestational-weight-gains, P4/E2 ratio, maternal liver and spleen indices, placental and fetal weights, and offspring survival. Placental and decidual structural and functional markers were also impaired. L-ALAN disrupted core-circadian-clock-gene expression and increased inflammatory cytokines in the maternal-placenta-decidual-fetal tissues. MT supplementation partially attenuated several of these alterations, whereas maternal organ indices, fetal weights, and fetal liver inflammatory responses were not significantly restored. Gestational L-ALAN exposure suppressed circulating and placental MT secretion, induced gestational hormonal and metabolic dysfunctions and decreased placental/fetal weights. Impaired maternal–fetal interface architecture and function, secondary to circadian rhythm disturbances and inflammatory activation, underlies these detrimental effects, while MT supplementation partially attenuated selected L-ALAN-associated alterations. As the C57BL/6 J strain exhibits deficient pineal MT synthesis, these findings primarily reflect alterations in peripheral (circulating and placental) MT availability.
The high infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stems from the insertion of four distinct amino acid residues (RRAR), called polybasic cleavage site in the spike (S) protein, that is strikingly identical with that of epithelial sodium channel (ENaC), both of which can be cleaved by plasmin. Dysregulation of human ENaC, a protein responsible for regulating fluid balance, is directly associated with mortality resulting from pulmonary damage, whereas the involvement of ENaC and regulation by fibrinolytic system during SARS-CoV-2 infection remains elusive. In this study, S plasmid and pseudovirus were applied to mimic SARS-CoV-2 infection, respectively. Pulmonary edema manifestations and dysregulation of ENaC were observed in mice expressing human angiotensin converting enzyme 2, and mechanistic studies revealed both S protein and ENaC could be cleaved by plasmin. Furthermore, our results demonstrated that S protein competitively inhibited the cleavage of ENaC by plasmin, overexpression of ENaC suppressed plasmin-induced cleavage of the S protein, thereby impeding SARS-CoV-2 invasion. Notably, co-enabling the polybasic cleavage site mutated S plasmid/pseudovirus with plasmin reversed the downregulation of ENaC. In conclusion, our data suggest a competitive mechanism of ENaC by SARS-CoV-2 via plasmin was mainly regulated at polybasic cleavage site, indicating a novel mechanism underlying SARS-CoV-2-induced pulmonary edema, and identifying ENaC as a potential therapeutic target for treating SARS-CoV-2-associated respiratory failure.
