Oil mistparticulate matter exposure induces hyperlipidemia-related inflammation via microbiota/ SCFAs/GPR43 axis inhibition and TLR4/NF-κB activation.

Metabolites produced by the human gut microbiota play an important role in fighting and intervening in inflammatory diseases. It remains unknown whether immune homeostasis is influenced by increasing concentrations of air pollutants such as oil mist particulate matters (OMPM). Herein, we report that OMPM exposure induces a hyperlipidemia-related phenotype through microbiota dysregulation-mediated downregulation of the anti-inflammatory short-chain fatty acid (SCFA)-GPR43 axis and activation of the inflammatory pathway. A rat model showed that exposure to OMPM promoted visceral and serum lipid accumulation and inflammatory cytokine upregulation. Furthermore, our research indicated a reduction in both the "healthy" microbiome and the production of SCFAs in the intestinal contents following exposure to OMPM. The SCFA receptor GPR43 was downregulated in both the ileum and white adipose tissues (WATs). The OMPM treatment mechanism was as follows: the gut barrier was compromised, leading to increased levels of lipopolysaccharide (LPS). This increase activated the Toll-like receptor 4 Nuclear Factor-κB (TLR4-NF-κB) signaling pathway in WATs, consequently fueling hyperlipidemia-related inflammation through a positive-feedback circuit. Our findings thus imply that OMPM pollution leads to hyperlipemia-related inflammation through impairing the microbiota-SCFAs-GPR43 pathway and activating the LSP-induced TLR4-NF-κB cascade; our findings also suggest that OMPM pollution is a potential threat to humanmicrobiota dysregulation and the occurrence of inflammatory diseases.

Effects of Different Concentrations of Oil Mist Particulate Matter on Pulmonary Fibrosis In Vivo and In Vitro.

Oil-mist particulate matter (OMPM) refers to oily particles with a small aerodynamic equivalent diameter in ambient air. Since the pathogenesis of pulmonary fibrosis (PF) has not been fully elucidated, this study aims to explore the potential molecular mechanisms of the adverse effects of exposure to OMPM at different concentrations in vivo and in vitro on PF. In this study, rats and cell lines were treated with different concentrations of OMPM in vivo and in vitro. Sirius Red staining analysis shows that OMPM exposure could cause pulmonary lesions and fibrosis symptoms. The expression of TGF-ß1, α-SMA, and collagen I was increased in the lung tissue of rats. The activities of MMP2 and TIMP1 were unbalanced, and increased N-Cadherin and decreased E-Cadherin upon OMPM exposure in a dose-dependent manner. In addition, OMPM exposure could activate the TGF-ß1/Smad3 and TGF-ß1/MAPK p38 signaling pathways, and the differentiation of human lung fibroblast HFL-1 cells. Therefore, OMPM exposure could induce PF by targeting the lung epithelium and fibroblasts, and activating the TGF-ß1/Smad3 and TGF-ß1/MAPK p38 signaling pathways.

Different exposure modes of PM2.5 induces bronchial asthma and fibrosis in male rats through macrophage activation and immune imbalance induced by TIPE2 methylation.

Exposure to PM2.5 can aggravate the occurrence and development of bronchial asthma and fibrosis. Here, we investigated the differences in bronchial injury caused by different exposure modes of PM2.5 (high concentration intermittent exposure and low concentration continuous exposure), and the mechanism of macrophage activation and respiratory immune imbalance induced by PM2.5, leading to bronchial asthma and airway fibrosis using animal and cell models. A "PM2.5 real-time online concentrated animal whole-body exposure system" was used to conduct PM2.5 respiratory exposure of Wistar rats for 12 weeks, which can enhance oxidative stress in rat bronchus, activate epithelial cells and macrophages, release chemokines, recruit inflammatory cells, release inflammatory factors and extracellular matrix, promote bronchial mucus hypersecretion, inhibit the expression of epithelial cytoskeletal proteins, destroy airway barrier, and induce asthma. Furthermore, PM2.5 induced M2 polarization in lung bronchial macrophages through JAK/STAT and PI3K/Akt signaling pathways, and compared with low concentration continuous exposure, high concentration intermittent exposure of PM2.5 could regulate significantly higher expression of TIPE2 protein through promoter methylation of TIPE2 DNA, thereby activating PI3K/Akt signaling pathway and more effectively inducing M2 polarization of macrophages. Additionally, activated macrophages release IL-23, and activated epithelial cells and macrophages released TGF-ß1, which promoted the differentiation of Th17 cells, triggered the Th17 dominant immune response, and activated the TGF-ß1/Smad2 signaling pathway, finally causing bronchial fibrosis. Moreover, when the total amount of PM2.5 exposure was equal, high concentration-intermittent exposure was more serious than low concentration-continuous exposure. In vitro experiments, the co-culture models of PM2.5 with BEAS-2B, WL-38 and rat primary alveolar macrophages further confirmed that PM2.5 could induce the macrophage activation through oxidative stress and TIPE2 DNA methylation, and activate the TGF-ß1/Smad2 signaling pathway, leading to the occurrence of bronchial fibrosis.

Combined multi-omics analysis reveals oil mist particulate matter-induced lung injury in rats: Pathological damage, proteomics, metabolic disturbances, and lung dysbiosis.

Oil mist particulate matter (OMPM) causes acute and chronic diseases and exacerbations. Owing to the characteristics of poor ventilation, high oil mist concentration, and a relatively closed working environment, the existence of OMPM in the cabin is inevitable, and its impact on the health of occupations on ships cannot be ignored. However, compared with several studies that summarized the health effects of OMPM from traditional sources, few studies have focused on the occupational exposure risk of OMPM from oil pollution sources in ships. In this study, we collected OMPM from oil pollution in cabins and assessed the exposure to OMPM from oil pollution and the corresponding health risks through acute exposure experiments in rats. OMPM exposure induces protein regulation in the extracellular matrix and immune responses, leading to severe inflammatory responses. The abundance and composition of the lung microbial community changed significantly. It interferes with the lung metabolite levels. However, more research is needed to fully understand the extent of health risks associated with OMPM exposure. Further research on vulnerable groups exposed to OMPM from ships is needed to inform public health interventions.

[Effect of epithelial-mesenchymal transition on cardiac fibrosis induced by oil mist particulate matter].

Objective: To investigate the effects of oil-mist particulate matter (OMPM) on cardiac tissue structure fibrosis in rats and the role of epithelial-mesenchymal transition (EMT). Methods: Six-week-old Wistar rats (half male and half female) were randomly divided into 3 groups: control group (without OMPM exposure), low-dose exposure group (50 mg/m3) and high-dose exposure group (100 mg/m3), 18 rats in each group, with 6.5 hours per day of dynamic inhalation exposure. After 42 days of continuous exposure, cardiac tissues were collected for morphological observation; Western blot was used to detect fibrosis markers collagen I and collagen III levels, epithelial marker E-cadherin levels, interstitial markers N-cadherin, fibronectin, vimentin, alpha-smooth muscle actin (α-SMA) levels, and EMT transcription factor Twist protein levels; Real-time polymerase chain reaction (RT-qPCR) was used to detect collagen I and collagen III mRNA levels. Results: After OMPM exposure, myocardial cell edema and collagen fiber deposition were increased gradually with increasing exposure dose. Western blot results showed that compared with the control group, the expression levels of collagen I, collagen III, N-Cadherin, fibronectin, vimentin, α-SMA, and Twist protein were increased significantly in the low-dose exposure group and the high-dose exposure group (P＜0.01), and protein expression levels were higher in the high-dose exposure group than those in the low-dose exposure group (P＜0.01). In contrast, E-Cadherin protein expression levels were decreased significantly, and lower in the high-dose exposure group (P＜0.01). RT-qPCR results showed that compared with the control group, collagen I and collagen III mRNA levels were increased significantly in the low-dose exposure group and the high-dose exposure group (P＜0.01), and were increased with increasing exposure dose. (P＜0.01). Conclusion: OMPM may induce cardiac fibrosis in rats by promoting EMT process.

Exposure to copper oxide nanoparticles triggers oxidative stress and endoplasmic reticulum (ER)-stress induced toxicology and apoptosis in male rat liver and BRL-3A cell.

Copper oxide nanoparticles (Nano-CuO) toxicity has been researched widely in recent years. However, the relationship between oxidative stress and ER-stress and the possible mechanisms induced by Nano-CuO have been rarely studied. Here, the mechanism of hepatotoxicity and apoptosis through oxidative stress and ER-stress induced by Nano-CuO was investigated in vivo and in vitro. In in vivo experiments, male Wistar rats were intranasally instilled 10 µg Nano-CuO/g body weight daily for 60 days, which caused liver function impairment, oxidative stress, inflammatory response, histopathological and ultrastructural damage, ER-stress and apoptosis in liver tissue. in vitro experiments on rat hepatocytes BRL-3A cells showed that exposure to Nano-CuO for 24 h resulted in excess production of reactive oxygen species leading to decrease in mitochondria membrane potential causing cell death by inducing apoptosis. However, administration of n-acetyl cysteine decreased the apoptosis in Nano-cuo treated group. The in vivo and in vitro experiments confirmed that oxidative stress triggered ER-stress pathway, leading to the opening of apoptosis pathways of CHOP, JNK, and Caspase-12. In summary, treatment of Nano Cuo triggered oxidative stress by ROS, which in turn resulted in activation of ER stress pathways causing cell death in liver tissue and BRL-3A cells.