Polystyrene nanoplastics-induced lung apoptosis and ferroptosis via ROS-dependent endoplasmic reticulum stress

Role of PERK-Mediated Endoplasmic Reticulum Stress in Ferroptosis Caused by Hexavalent Chromium in Chicken Hepatocytes

This study aimed to investigate whether Cr(VI) can induce ferroptosis in chicken hepatocytes and determine the role of PERK-mediated endoplasmic reticulum stress (ERS). First, a model of Cr(VI) poisoning was established by exposing chicken hepatocytes to Cr(VI). The levels of ferroptosis-related proteins, meanwhile, GSH, SOD, MDA, and lipid ROS, were measured. Furthermore, the expression of GRP78 and PERK proteins was examined. Changes in ERS and ferroptosis were evaluated by silencing the PERK gene. Results showed that Cr(VI) led to the accumulation of lipid ROS, decreased expression of GPX4 and HSP27, increased expression of COX2, and induced ferroptosis in chicken hepatocytes. Exposure to Cr(VI) increased the protein expression of GRP78 and PERK, and silencing of PERK worsened Cr(VI)-induced ferroptosis. In conclusion, Cr(VI) can induce ferroptosis in chicken hepatocytes, and PERK plays an important role as a negative regulator.

Inhaled polystyrene microplastics impaired lung function through pulmonary flora/TLR4-mediated iron homeostasis imbalance

Microplastics (MPs) have been found in the air, human nasal cavity, and lung, suggesting that the respiratory tract is one of the important exposure routes for MPs. The lung is a direct target organ for injury from inhaled MPs, but data on lung injury from longer-term exposure to environmental doses of MPs are limited, and the mechanisms remain unclear. Here, C57BL/6 J mice were treated with 5 μm polystyrene (PS)-MPs by intratracheal instillation (0.6, 3, and 15 mg/kg) for 60 days to establish MPs exposure model. We found that PS-MPs lead to increased collagen fibers and decreased lung barrier permeability and lung function in lung tissue. Mechanistically, the abundance of gram-negative bacteria in the pulmonary flora increased after inhalation of PS-MPs, causing lipopolysaccharide (LPS) release. The expression of Toll-like receptor 4 (TLR4), the key receptor of LPS, was increased, and ferroptosis occurred in lung tissue cells. Further in vitro intervention experiments were performed, pulmonary flora/TLR4-induced imbalance of lung iron homeostasis is an important mechanism of PS-MPs-induced lung injury. Our study provides new evidence for lung injury caused by environmental doses of MPs and strategies to prevent it through longer-term dynamic observation.

F-53B stimulated vascular smooth muscle cell phenotypic switch and vascular remodeling via ferroptosis-related pathway

The compound 6:2 chlorinated polyfluorinated ether sulfonate (F53B), an alternative to perfluorooctane sulfonate (PFOS), has been widely utilized in China. Although the connection between the exposure and toxicity of F53B is established, the role and mechanisms of the compound in promoting vascular remodeling are yet to be elucidated. Thus, the present study investigated the impact of F53B on the function of vascular smooth muscle cells (VSMCs) and vascular remodeling. The data exhibited that F53B stimulates vascular morphological alterations in vivo, and exposure to the compound caused excessive VSMCs ferroptosis and phenotype switching, as determined using phenotype and molecular assays. Moreover, Fer-1 reversed F-53B-induced VSMC dysfunction and vascular remodeling. Furthermore, F53B activated the ferroptosis-related pathway, encompassing ATR expression and LOC101929922/miR-542-3p/ACSL4 pathway. Thus, the current results elaborated on the multifaceted toxicities of F53B that induce vascular remodeling, thereby necessitating the assessment of vasotoxicity risks associated with the compound.

Lung microbiota participated in fibrous microplastics (MPs) aggravating OVA-induced asthma disease in mice

Environmental pollution is one of the risk factors for asthma. Currently, whether micro-plastics could aggravate asthma, is still unclear. In the air, fibrous MPs are the predominant shape. Since fibrous micro-plastics are reported to be detected in the lower respiratory tract and other body parts, the relationship of fibrous MP and asthma, as well as the potential mechanism is not well investigated. In this study, we produced fibrous MPs, whose lengths and widths were in accordance with the natural environment, and further, investigated the potential adverse effect of which on the asthma in a OVA (ovalbumin)-induced mice model, aiming at exploring the true life hazard of MP to the respiratory system. Following nasal exposure to fibrous MPs, the airway inflammation, mucus hypersecretion and fibrosis were aggravated in asthmatic mice. Fibrous MPs exposure also significantly increased the levels of total IgE, and, cardinal Th2 and Th1 pro-inflammatory cytokines participated in the etiopathogenesis of allergic airway inflammation. In addition, MP fibers exposure induced lung epithelial cells apoptosis, disruption of epithelial barrier integrity and activation of NLRP3 related signaling pathways. Moreover, fibrous MPs significantly altered the bacterial composition at the genus level. Compared to the control group, the relative abundance of Escherichia-Shigella and Uncultured were decreased to 4.47% and 0.15% in OVA group, while Blautia and Prevotella were elevated to 4.96% and 2.94%. For the OVA + MPs group, the relative abundance of Blautia and Uncultured were decreased to 2.27% and 0.006%, while Prevotella was increased to 3.05%. Our study highlights the detrimental effect of fibrous MPs on asthmatic population and facilitates an indication of the latent mechanisms of fibrous MPs induced airway pathology.

Baicalin protects against hepatocyte injury caused by aflatoxin B1 via the TP53-related ferroptosis Pathway

OBJECTIVE

Baicalin has antioxidative, antiviral, and anti-inflammatory properties. However, its ability to alleviate oxidative stress (OS) and DNA damage in liver cells exposed to aflatoxin B1 (AFB1), a highly hepatotoxic compound, remains uncertain. In this study, the protective effects of baicalin on AFB1-induced hepatocyte injury and the mechanisms underlying those effects were investigated.

METHODS

Stable cell lines expressing CYP3A4 were established using lentiviral vectors to assess oxidative stress levels by conducting assays to determine the content of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Additionally, DNA damage was evaluated by 8-hydroxy-2-deoxyguanosine (8-OHdG) and comet assays. Transcriptome sequencing, molecular docking, and in vitro experiments were conducted to determine the mechanisms underlying the effects of baicalin on AFB1-induced hepatocyte injury. In vivo, a rat model of hepatocyte injury induced by AFB1 was used to evaluate the effects of baicalin.

RESULTS

In vitro, baicalin significantly attenuated AFB1-induced injury caused due to OS, as determined by a decrease in ROS, MDA, and SOD levels. Baicalin also considerably decreased AFB1-induced DNA damage in hepatocytes. This protective effect of baicalin was found to be closely associated with the TP53-mediated ferroptosis pathway. To elaborate, baicalin physically interacts with P53, leading to the suppression of the expression of GPX4 and SLC7A11, which in turn inhibits ferroptosis. In vivo findings showed that baicalin decreased DNA damage and ferroptosis in AFB1-treated rat liver tissues, as determined by a decrease in the expression of γ-H2AX and an increase in GPX4 and SLC7A11 levels. Overexpression of TP53 weakened the protective effects of baicalin.

CONCLUSIONS

Baicalin can alleviate AFB1-induced OS and DNA damage in liver cells via the TP53-mediated ferroptosis pathway. In this study, a theoretical foundation was established for the use of baicalin in protecting the liver from the toxic effects of AFB1.

Nanoplastic-Induced Liver Damage Was Alleviated by Maltol via Enhancing Autophagic Flow: An In Vivo and In Vitro Study

In recent years, there has been a growing concern regarding health issues arising from exposure to nanoplastics (Nps) in the natural environment. The Nps bioaccumulate within the body via the circulatory system and accumulate in the liver, resulting in damage. Previous studies have demonstrated that maltol, derived from red ginseng (Panax ginseng C.A. Meyer) as a Maillard product, exhibits hepatoprotective effects by alleviating liver damage caused by carbon tetrachloride or cisplatin. In order to explore the specific mechanism of maltol in improving hepatotoxicity induced by Nps, mice exposed to 100 mg/kg Nps were given maltol at doses of 50 and 100 mg/kg, respectively. The results showed that Nps induced an increase in the levels of liver apoptotic factors BAX and cytochrome c, a decrease in the levels of the autophagy key gene LC3 II/I, and an increase in P62. It also caused oxidative stress by affecting the Nrf2/HO-1 pathway, and a decrease in GPX4 protein expression suggested the occurrence of ferroptosis. However, treatment with maltol significantly improved these changes. In addition, maltol (2, 4, and 8 μM) also protected human normal liver L02 cells from Np (400 μg/mL)-induced damage. Our data suggest that maltol could ameliorate Np-induced L02 cytotoxicity by reducing autophagy-dependent oxidative stress, exhibiting similar protective effects in vitro as in vivo. This study helps shed light on the specific molecular mechanism of Np-induced hepatotoxicity. For the first time, we studied the protective effect of maltol on Np-induced liver injury from multiple perspectives, expanding the possibility of treatment for diseases caused by environmental pollutants.

Polystyrene nanoplastics exposure causes erectile dysfunction in rats

Polystyrene nanoplastics (PS-NPs), emerging and increasingly pervasive environmental contaminants, have the potential to cause persistent harm to organisms. Although previous reports have documented local accumulation and adverse effects in a variety of major organs after PS-NPs exposure, the impact of PS-NPs exposure on erectile function remains unexplored. Herein, we established a rat model of oral exposure to 100 nm PS-NPs for 28 days. To determine the best dose range of PS-NPs, we designed both low-dose and high-dose PS-NPs groups, which correspond to the minimum and maximum human intake doses, respectively. The findings indicated that PS-NPs could accumulate within the corpus cavernosum and high dose but not low dose of PS-NPs triggered erectile dysfunction. Moreover, the toxicological effects of PS-NPs on erectile function include fibrosis in the corpus cavernous, endothelial dysfunction, reduction in testosterone levels, elevated oxidative stress and apoptosis. Overall, this study revealed that PS-NPs exposure can cause erectile dysfunction via multiple ways, which provided new insights into the toxicity of PS-NPs.

Exposure to polystyrene nanoplastics induces abnormal activation of innate immunity via the cGAS-STING pathway

Endogenous immune defenses provide an intrinsic barrier against external entity invasion. Microplastics in the environment, especially those at the nanoscale (nanoplastics or NPs), may pose latent health risks through direct exposure. While links between nanoplastics and inflammatory processes have been established, detailed insights into how they may perturb the innate immune mechanisms remain uncharted. Employing murine and macrophage (RAW264.7) cellular models subjected to polystyrene nanoplastics (PS-NPs), our investigative approach encompassed an array of techniques: Cell Counting Kit-8 assays, flow cytometric analysis, acridine orange/ethidium bromide (AO/EB) fluorescence staining, cell transfection, cell cycle scrutiny, genetic manipulation, messenger RNA expression profiling via quantitative real-time PCR, and protein expression evaluation through western blotting. The results showed that PS-NPs caused RAW264.7 cell apoptosis, leading to cell cycle arrest, and activated the cGAS-STING pathway. This resulted in NF-κB signaling activation and increased pro-inflammatory mediator expression. Importantly, PS-NPs-induced activation of NF-κB and its downstream inflammatory cascade were markedly diminished after the silencing of the STING gene. Our findings highlight the critical role of the cGAS-STING pathway in the immunotoxic effects induced by PS-NPs. We outline a new mechanism whereby nanoplastics may trigger dysregulated innate immune and inflammatory responses via the cGAS/STING pathway.