Hepatoprotective Effect of Loquat Leaf Flavonoids in PM2.5-Induced Non-Alcoholic Fatty Liver Disease via Regulation of IRs-1/Akt and CYP2E1/JNK Pathways

Intestinal Bacterial Dysbiosis and Liver Fibrosis in Mice Through Gut-Liver Axis and NLRP3 Inflammatory Pathway Caused by Fine Particulate Matter

Fine particulate matter (PM2.5) is associated with risks of liver diseases and intestinal bacterial dysbiosis, in which the gut-liver axis regulation mechanisms induced by PM2.5 exposure are still limited so far. In this study, after 12 weeks of exposure to atmospheric PM2.5 (64 μg/m3) and clean air in winter in Taiyuan, China, we collected liver and intestinal tissues and serum in male mice to perform toxicology experiments. The results showed that PM2.5 significantly exacerbated the pathological injury in the liver and intestine and liver fibrosis in mice, along with elevated levels of pro-inflammatory cytokines and lipopolysaccharide (LPS) levels in the serum. PM2.5 caused abnormal liver function and activated TLR4/NF-κB/NLRP3 pathway in mouse liver. PM2.5 also significantly inhibited the expression of intestinal mucosal tight junction proteins such as ZO-1 and occludin. Besides, from 16S rRNA gene sequencing results in intestinal and fecal samples, we found that PM2.5 decreased the diversity and abundance of intestinal bacteria, along with reducing Shannon, Chao1 and Ace indices and increasing Simpson indices. Principal component analysis (PCA) showed that mice's intestinal bacterial composition and β-diversity in the PM2.5-exposed group significantly differed from the control group. KEGG pathway analyzed key functional genes and metabolic pathways in important mouse bacterial communities in the PM2.5-exposed group. It suggested that PM2.5 exposure exacerbates liver fibrosis in mice via the NLRP3 pathway. PM2.5 caused intestinal mucosal injury, intestinal bacterial disorders and increased LPS levels, leading to the activation of inflammatory pathways, which can exacerbate liver fibrosis via the gut-liver axis.

Exploring the association between air pollution and the incidence of liver cancers

Liver cancer, namely hepatocellular carcinoma (HCC), is a major global health concern deeply influenced by environmental factors. Air pollutants emerged as significant contributors to its incidence. This review explores the association between air pollution-specifically particulate matter (PM2.5), industrial chemicals like vinyl chloride, and benzene-and the increased risk of liver cancer. Mechanistically, air pollutants may cause liver damage by inducing oxidative stress, inflammation, and genetic mutations, contributing to cancer development. Epidemiological evidence from cohort and geographic studies highlights a positive correlation between long-term exposure to air pollutants and elevated incidence and mortality of liver cancer. Furthermore, air pollution has been shown to worsen survival outcomes in liver cancer patients, particularly those diagnosed at early stages. The review emphasizes the need for stricter air quality regulations and relevant research for underlying mechanisms exposed to air pollution. Addressing air pollution exposure could be crucial for reducing liver cancer risks and improving public health outcomes.

Integrated bioinformatics and multiomics reveal Liupao tea extract alleviating NAFLD via regulating hepatic lipid metabolism and gut microbiota

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) poses a significant global public health concern. Liupao tea (LPT) is a Chinese national geographical indication product renowned for its lipid-lowering properties. However, the precise mechanisms and active constituents contributing to the efficacy of LPT against NAFLD remain unclear.

PURPOSE

This study aims to comprehensively explore the therapeutic potential of Liupao tea extract (LPTE) in alleviating NAFLD through an integrated strategy.

METHODS

Initially, network pharmacology analysis was conducted based on LPTE chemical ingredient analysis, identifying core targets and key components. Potential active ingredients were validated through chemical standards based on LC-MS/MS. To confirm the pharmacological efficacy of LPTE in NAFLD, NAFLD mice models were employed. Alterations in hepatic lipid metabolism were comprehensively elucidated through integration of metabolomics, lipidomics, network pharmacology analysis, and real-time PCR analysis. To further explore the binding interactions between key components and core targets, molecular docking and microscale thermophoresis (MST) analysis were employed. Furthermore, to investigate LPTE administration effectiveness on gut microbiota in NAFLD mice, a comprehensive approach was employed. This included Metorigin analysis, 16S rRNA sequencing, molecular docking, and fecal microbiome transplantation (FMT).

RESULTS

Study identified naringenin, quercetin, luteolin, and kaempferol as the potential active ingredients of LPTE. These compounds exhibited therapeutic potential for NAFLD by targeting key proteins such as PTGS2, CYP3A4, and ACHE, which are involved in the metabolic pathways of hepatic linoleic acid (LA) and glycerophospholipid (GP) metabolism. The therapeutic effectiveness of LPTE was observed to be comparable to that of simvastatin. Furthermore, LPTE exhibited notable efficacy in alleviating NAFLD by influencing alterations in gut microbiota composition (Proteobacteria phylum, Lactobacillus and Dubosiella genus) that perhaps impact LA and GP metabolic pathways.

CONCLUSION

LPTE could be effective in preventing high-fat diet (HFD)-induced NAFLD by modulating hepatic lipid metabolism and gut microbiota. This study firstly integrated bioinformatics and multi-omics technologies to identify the potential active components and key microbiota associated with LPTE's effects, while also primally elucidating the action mechanisms of LPTE in alleviating NAFLD. The findings offer a conceptual basis for LPTE's potential transformation into an innovative pharmaceutical agent for NAFLD prevention.

Cross-Omics Analyses Reveal the Effects of Ambient PM2.5 Exposure on Hepatic Metabolism in Female Mice

Ambient particulate matter (PM2.5) is a potential risk factor for metabolic damage to the liver. Epidemiological studies suggest that elevated PM2.5 concentrations cause changes in hepatic metabolism, but there is a lack of laboratory evidence. Here, we aimed to evaluate the effects of PM2.5 exposure on liver metabolism in C57BL/6j female mice (10 months old) and to explore the mechanisms underlying metabolic alterations and differential gene expressions by combining metabolomics and transcriptomics analyses. The metabolomics results showed that PM2.5 exposure notably affected the metabolism of amino acids and organic acids and caused hepatic lipid and bile acid accumulation. The transcriptomic analyses revealed that PM2.5 exposure led to a series of metabolic pathway abnormalities, including steroid biosynthesis, steroid hormone biosynthesis, primary bile acid biosynthesis, etc. Among them, the changes in the bile acid pathway might be one of the causes of liver damage in mice. In conclusion, this study clarified the changes in liver metabolism in mice caused by PM2.5 exposure through combined transcriptomic and metabolomic analyses, revealed that abnormal bile acid metabolism is the key regulatory mechanism leading to metabolic-associated fatty liver disease (MAFLD) in mice, and provided laboratory evidence for further clarifying the effects of PM2.5 on body metabolism.

Ultrasound-assisted deep eutectic solvents extraction of polysaccharides from Loquat leaf: Process optimization and bioactivity study

Loquat leaves are the by-product of loquat fruit production. Polysaccharides are one of the main active ingredients in loquat leaves. In this study, polysaccharides were extracted from loquat leaves by ultrasonic-assisted deep eutectic solvents (DESs) extraction method. Further, the extracted crude loquat leaf polysaccharides (CLLP) were purified and separated via S-8 resin and DEAE-52 cellulose column chromatography, respectively. Additionally, the effects of polysaccharides on activity of sperm in boar semen preserved in medium at 17 °C, were evaluated preliminarily. DES, composed of choline chloride/ethylene glycol (1:6, molar ratio), was proved to be the suitable solvent for LLP extraction. The optimized extraction conditions were water content 44 %, liquid-solid ratio 1:29 (g/g), extraction temperature 61 °C and extraction time 98 min. Under these conditions, the LLP yield was 57.82 ± 1.50 mg/g. A homogeneous polysaccharide (LLP1-2, Mw: 2.17 × 104 Da) was isolated from CLLP. Its total sugar, uronic acid and protein contents were 76.31 ± 1.25 %, 14.19 ± 0.67 % and 3.28 ± 0.42 %, respectively. Further, 800 μg/mL LLP1-2 could effectively enhance the antioxidant activity of sperm. This study laid a foundation for DESs and column chromatography in the field of polysaccharide extraction and separation, proving that LLP can be used as a natural antioxidant for sperm preservation.

PM2.5 induced liver lipid metabolic disorders in C57BL/6J mice

PM2.5 can cause adverse health effects via several pathways, such as inducing pulmonary and systemic inflammation, penetration into circulation, and activation of the autonomic nervous system. In particular, the impact of PM2.5 exposure on the liver, which plays an important role in metabolism and detoxification to maintain internal environment homeostasis, is getting more attention in recent years. In the present study, C57BL/6J mice were randomly assigned and treated with PM2.5 suspension and PBS solution for 8 weeks. Then, hepatic tissue was prepared and identified by metabolomics analysis and transcriptomics analysis. PM2.5 exposure can cause extensive metabolic disturbances, particularly in lipid and amino acids metabolic dysregulation.128 differential expression metabolites (DEMs) and 502 differently expressed genes (DEGs) between the PM2.5 exposure group and control group were detected. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that DEGs were significantly enriched in two disease pathways, non-alcoholic fatty liver disease (NAFLD) and type II diabetes mellitus (T2DM), and three signaling pathways, which are TGF-beta signaling, AMPK signaling, and mTOR signaling. Besides, further detection of acylcarnitine levels revealed accumulation in liver tissue, which caused restricted lipid consumption. Furthermore, lipid droplet accumulation in the liver was confirmed by Oil Red O staining, suggesting hepatic steatosis. Moreover, the aberrant expression of three key transcription factors revealed the potential regulatory effects in lipid metabolic disorders, the peroxisomal proliferative agent-activated receptors (PPARs) including PPARα and PPARγ is inhibited, and the activated sterol regulator-binding protein 1 (SREBP1) is overexpressed. Our results provide a novel molecular and genetic basis for a better understanding of the mechanisms of PM2.5 exposure-induced hepatic metabolic diseases, especially in lipid metabolism.

Preventive and therapeutic effects of natural products and herbal extracts on nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a common condition that is prevalent in patients who consume little or no alcohol, and is characterized by excessive fat accumulation in the liver. The disease is becoming increasingly common with the rapid economic development of countries. Long-term accumulation of excess fat can lead to NAFLD, which represents a global health problem with no effective therapeutic approach. NAFLD is a complex, multifaceted pathological process that has been the subject of extensive research over the past few decades. Herbal medicines have gained attention as potential therapeutic agents to prevent and treat NAFLD due to their high efficacy and low risk of side effects. Our overview is based on a PubMed and Web of Science database search as of Dec 22 with the keywords: NAFLD/NASH Natural products and NAFLD/NASH Herbal extract. In this review, we evaluate the use of herbal medicines in the treatment of NAFLD. These natural resources have the potential to inform innovative drug research and the development of treatments for NAFLD in the future.

Resveratrol reversed ambient particulate matter exposure-perturbed oscillations of hepatic glucose metabolism by regulating SIRT1 in mice

Much evidence has shown that ambient particulate matter (PM) exposure is associated with abnormal glucose metabolism, but the underlying mechanism has not yet been fully characterized. Circadian disruption has adverse effects on glucose metabolism. In this study, we investigated the effects of long-term ambient PM exposure on the hepatic circadian clock and the expression rhythm of genes associated with hepatic glucose metabolism in mice. C57BL/6 mice were exposed to filtered air (FA), ambient PM, or ambient PM plus resveratrol (RES). After 15 weeks (12 h per day, 7 days per week) of exposure, glucose homeostasis, the rhythmic expression of clock genes, and genes associated with hepatic glucose metabolism were determined. Our results found that PM exposure induced glucose metabolism disorder and perturbed the rhythmic mRNA expression of core clock genes and their target genes involved in hepatic glucose metabolism. Mechanistic investigations demonstrated that ambient PM exposure markedly altered the expression patterns of BMAL1, clock, and SIRT1 in vivo. Simultaneously, we demonstrated that RES (an activator of SIRT1) changed the expression pattern of SIRT1, thereby reversing the rhythm misalignment of BMAL1 and clock and hepatic glucose metabolism disorder induced by ambient PM exposure. In addition, PM_2.5 exposure perturbed the rhythmic protein expression of BMAL1, clock, and SIRT1 in L-02 cells. Simultaneously, we demonstrated that RES restored the SIRT1 circadian rhythm, which reversed the rhythm misalignment of BMAL1 and clock in L-02 cells induced by PM_2.5 exposure. Taken together, our results suggested that long-term ambient PM exposure perturbed the hepatic core circadian clock rhythm and caused glucose metabolism disorder, which could be reversed by RES supplementation. Our study offers a potential application of RES for combating circadian misalignment-related metabolic diseases.

Effect of Fine Particulate Matter Exposure on Liver Enzymes: A Systematic Review and Meta-Analysis

Although previous studies have presented that fine particulate matter (PM2.5) regulates liver enzyme levels in the development of liver diseases, the evidence regarding the relationship between PM2.5 exposure and liver enzyme is not robust. We further aimed to conduct a systematic review and meta-analysis of observational studies to summarize the recent evidence on the effects of PM2.5 on liver enzyme in humans. In the meta-analysis, we retrieved online databases including PubMed and Web of Science database from 1982 up to 2022. A random-effects model was applied to evaluate the correlation between PM2.5 and liver enzyme level. A total of 10 studies fulfilled the inclusion criteria, including five prospective cohort studies, two cross-sectional studies, two longitudinal studies, and one time-series analysis. Each 10 μg/m3 increase in PM2.5 concentration was significantly correlated with a 4.45% increase in alanine aminotransferase (ALT) level (95% CI: 0.51-8.38%, p = 0.03), a 3.99% increase in aspartate transferase (AST) level (95% CI: 0.88-7.10%, p = 0.01), and a 2.91% increase in gamma-glutamyl transferase (GGT) level (95% CI: 1.18-4.64%, p < 0.001), but this significant association was not observed in alkaline phosphatase (ALP). Subgroup analysis revealed that PM2.5 has a significant correlation with ALT (5.07%, 95% CI: 0.81-9.33%), AST (4.11%, 95% CI: 0.74-7.48%), and GGT (2.74%, 95% CI: 1.09-4.38%) in Asia. Our meta-analysis showed that increments in PM2.5 exposure were significantly associated with a higher level of ALT, AST, and GGT. In addition, investigations into liver enzyme subtypes and specific chemical components of PM2.5 are important directions for future research.

Mining biomarkers from routine laboratory tests in clinical records associated with air pollution health risk assessment

Clinical laboratory in hospital can produce amounts of health data every day. The purpose of this study was to mine biomarkers from clinical laboratory big data associated with the air pollution health risk assessment using clinical records. 13, 045, 629 clinical records of all 27 routine laboratory tests in Changsha Central Hospital, including ALB, TBIL, ALT, DBIL, AST, TP, UREA, UA, CREA, GLU, CK, CKMB, LDL-C, TG, TC, HDL-C, CRP, WBC, Na, K, Ca, Cl, APTT, PT, FIB, TT, RBC and those daily air pollutants concentration monitoring data of Changsha, including PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ from 2014 to 2016, were retrieved. The moving average method was used to the biological reference interval was established. The tests results were converted into daily abnormal rate. After data cleaning, GAM statistical model construction and data analysis, a concentration-response relationship between air pollutants and daily abnormal rate of routine laboratory tests was observed. Our study found that PM_2.5 had a stable association with TP (lag07), ALB (lag07), ALT (lag07), AST (lag07), TBIL (lag07), DBIL (lag07), UREA (lag07), CREA (lag07), UA (lag07), CK (lag 06), GLU (lag07), WBC (lag07), Cl (lag07) and Ca (lag07), (P < 0.05); O₃ had a stable association with AST (lag01), CKMB (lag06), TG (lag07), TC (lag05), HDL-C (lag07), K (lag05) and RBC (lag07) (P < 0.05); CO had a stable association with UREA (lag07), Na (lag7) and PT (lag07) (P < 0.05); SO₂ had a stable association with TP (lag07) and LDL-C (lag0) (P < 0.05); NO₂ had a stable association with APTT (lag7) (P < 0.05). These results showed that different air pollutants affected different routine laboratory tests and presented different pedigrees. Therefore, biomarkers mined from routine laboratory tests may potentially be used to low-cost assess the health risks associated with air pollutants.

Amelioration of Hepatic Steatosis by the Androgen Receptor Inhibitor EPI-001 in Mice and Human Hepatic Cells Is Associated with the Inhibition of CYP2E1

Nonalcoholic fatty liver disease (NAFLD) is recognized as a metabolic disease characterized by hepatic steatosis. Despite the growing burden of NAFLD, approved pharmacological treatment is lacking. As an inhibitor of androgen receptor (AR), EPI-001 is being explored for the treatment of prostate cancer. This study aimed to investigate the potential of EPI-001 for treating NAFLD in free fatty acids (FFAs)-induced human hepatic cells and high-fat-high-sugar (HFHS)-feeding mice. Our results showed that EPI-001 reduced lipid accumulation in hepatic cells and ameliorated hepatic steatosis in mouse livers. Further exploration suggested that the effect of EPI-001 was associated with CYP2E1-mediated reduction of reactive oxygen species (ROS). This provides encouraging evidence for further studies on EPI-001 therapy for NAFLD.

Traditional uses, phytochemistry, pharmacology, and toxicity of Eriobotrya japonica leaves: A summary

ETHNOPHARMACOLOGICAL RELEVANCE

Eriobotrya japonica Lindl. has been included in "The Plant List" (http://www.theplantlist.org) and is the most widely researched species in its genus. E. japonica is a subtropical evergreen fruit tree belonging to the Rosaceae family. Its dried leaves are widely used in traditional Chinese herbal medicine to treat coughing caused by pulmonary inflammation, dyspnea due to asthma and cough, nausea caused by stomach disorders, restlessness, and thirst. Furthermore, it is used to treat stomach ache, ulcers, chronic bronchitis, cancer, and diabetes mellitus in Japanese folk medicine. However, no systematic reports on E. japonica leaves have been published before.

AIM OF THE STUDY

This review summarizes the available information on the traditional uses, phytochemistry, pharmacology, toxicity, and quality control of various extracts and phytoconstituents of E. japonica leaves.

MATERIALS AND METHODS

Relevant publications between 1931 and 2022 were considered. Chinese and English studies on E. japonica leaves were collected from databases, including PubMed, Web of Science, Elsevier, ACS Publications, Springer, and CNKI (Chinese). The traditional uses, phytochemistry, pharmacology, toxicity, and quality control of E. japonica leaves were reviewed.

RESULTS

Briefly, 164 compounds, including triterpenes, flavonoids, sesquiterpene glycosides, megastigmane derivatives, phenylpropanoids, and organic acids, have been identified from E. japonica leaves, in addition to 169 volatile oils. More than half of these compounds have not yet been reported to have pharmacological activities. Triterpenes and flavonoids are the most important bioactive compounds responsible for pharmacological activities, such as antidiabetic, anti-inflammatory, and antitumor activities. Other beneficial physiological effects such as antioxidant, hepatoprotective, bronchodilatory, antitussive, and expectorant effects and tracheal smooth muscle relaxation, protection against myocardial ischemia injury, and improved cognitive activities have also been reported. High doses of E. japonica leaf extracts have been used in laboratory animals, and no side effects or toxicity-symptoms have been observed.

CONCLUSIONS

The pharmacological activities of E. japonica leaves support their use in traditional Chinese herbal medicine. However, several aspects, such as the bioavailability, pharmacodynamics, pharmacokinetics, mechanism of action, and structure-activity relationships of the pure compounds isolated from E. japonica leaves, have not been studied yet and warrant further studies.

Melatonin alleviates PM2.5 -induced glucose metabolism disorder and lipidome alteration by regulating endoplasmic reticulum stress

Exposure to fine particulate matter (PM_2.5 ) was associated with an increased incidence of liver metabolic disease. Melatonin has been shown to prevent liver glucolipid metabolism disorders. However, whether melatonin could rescue PM_2.5 -induced liver metabolic abnormalities remains uncertain. This study was to evaluate the mitigating effect of melatonin on PM_2.5 -accelerated hepatic glucose metabolism imbalance in vivo and in vitro. Schiff periodic acid shiff staining and other results showed that PM_2.5 led to a decrease in hepatic glycogen reserve and an increase in glucose content, which was effectively alleviated by melatonin. Targeted lipidomics is used to identify lipid biomarkers associated with this process, including glycerolipids, glycerophospholipids, and sphingolipids. In addition, gene microarray and quantitative polymerase chain reaction analysis of ApoE^-/- mice liver suggested that PM_2.5 activated the miR-200a-3p and inhibited DNAJB9, and the targeting relationship was verified by luciferase reports for the first time. Further investigation demonstrated that DNAJB9 might motivate endoplasmic reticulum (ER) stress by regulating Ca²⁺ homeostasis, thus altering the protein expression of GSK3B, FOXO1, and PCK2. Meanwhile, melatonin effectively inhibited miR-200a-3p and glucose metabolism disorder. Knockout of miR-200a-3p in L02 cells revealed that miR-200a-3p is indispensable in the damage of PM_2.5 and the therapeutic effect of melatonin. In summary, melatonin alleviated PM_2.5 -induced liver metabolic dysregulation by regulating ER stress via miR-200a-3p/DNAJB9 signaling pathway. Our data provide a prospective targeted therapy for air pollution-related liver metabolism disorders.

Stropharia rugoso-annulata acetylated polysaccharides alleviate NAFLD via Nrf2/JNK1/AMPK signaling pathways

The acetylated Stropharia rugoso-annulata polysaccharides (ASRP) was successfully characterized, and the effects and mechanism on alleviating NAFLD were investigated in HFD-induced mice models. The characterization showed that ASRP was successfully acetylated and rich in galactose. The animal studies demonstrated that ASRP at the dose of 400 mg/kg possessed hepatoprotective effects by potential antioxidation, anti-inflammation and improving hepatocellular histopathology, with the possible mechanisms on regulating the JNK1/AP-1 and activating the Nrf2 signaling pathways. Besides, ASRP could improve the fat metabolism by activating the AMPK/SREBP-1c signaling pathways. The results provided basal theories for the development of ASRP on treating the NAFLD and its complications.

Melatonin Alleviates PM2.5-Induced Hepatic Steatosis and Metabolic-Associated Fatty Liver Disease in ApoE-/- Mice

Background

Exposure to fine particulate matter (PM_2.5) is associated with the risk of developing metabolic-associated fatty liver disease (MAFLD). Melatonin is the main secreted product of the pineal gland and has been reported to prevent hepatic lipid metabolism disorders. However, it remains uncertain whether melatonin could protect against PM_2.5-induced MAFLD.

Methods and Results

The purpose of our study was to investigate the mitigating effects of melatonin on hepatic fatty degeneration accelerated by PM_2.5 in vivo and in vitro. Histopathological analysis and ultrastructural images showed that PM_2.5 induced hepatic steatosis and lipid vacuolation in ApoE^−/− mice, which could be effectively alleviated by melatonin administration. Increased ROS production and decreased expression of antioxidant enzymes were detected in the PM_2.5-treated group, whereas melatonin showed recovery effects after PM_2.5-induced oxidative damage in both the liver and L02 cells. Further investigation revealed that PM_2.5 induced oxidative stress to activate PTP1B, which in turn had a positive feedback regulation effect on ROS release. When a PTP1B inhibitor or melatonin was administered, SP1/SREBP-1 signalling was effectively suppressed, while Nrf2/Keap1 signalling was activated in the PM_2.5-treated groups.

Conclusion

Our study is the first to show that melatonin alleviates the disturbance of PM_2.5-triggered hepatic steatosis and liver damage by regulating the ROS-mediated PTP1B and Nrf2 signalling pathways in ApoE^−/− mice. These results suggest that melatonin administration might be a prospective therapy for the prevention and treatment of MAFLD associated with air pollution.

CYP2E1 plays a suppressive role in hepatocellular carcinoma by regulating Wnt/Dvl2/β-catenin signaling

Objective

Knowledge of the role of CYP2E1 in hepatocarcinogenesis is largely based on epidemiological and animal studies, with a primary focus on the role of CYP2E1 in metabolic activation of procarcinogens. Few studies have directly assessed the effects of CYP2E1 on HCC malignant phenotypes.

Methods

The expression of CYP2E1 in HCC tissues was determined by qRT-PCR, western blotting and immunohistochemistry. Overexpression of CYP2E1 in HCC cell was achieved by lentivirus transfection. The function of CYP2E1 were detected by CCK-8, wound healing, transwell assays, xenograft models and pulmonary metastasis model. TOP/FOPFlash reporter assay, western blotting, functional rescue experiments, Co-immunoprecipitation and reactive oxygen species detection were conducted to reveal the underlying mechanism of the tumor suppressive role of CYP2E1.

Results

CYP2E1 expression is down-regulated in HCC tissues, and this downregulation was associated with large tumor diameter, vascular invasion, poor differentiation, and shortened patient survival time. Ectopic expression of CYP2E1 inhibits the proliferation, invasion and migration and epithelial-to-mesenchymal transition of HCC cells in vitro, and inhibits tumor formation and lung metastasis in nude mice. Mechanistic investigations show that CYP2E1 overexpression significantly inhibited Wnt/β-catenin signaling activity and decreased Dvl2 expression in HCC cells. An increase in Dvl2 expression restored the malignant phenotype of HCC cells. Notably, CYP2E1 promoted the ubiquitin-mediated degradation of Dvl2 by strengthening the interaction between Dvl2 and the E3 ubiquitin ligase KLHL12 in CYP2E1-stable HCC cells. CYP2E1-induced ROS accumulation was a critical upstream event in the Wnt/β-Catenin pathway in CYP2E1-overexpressing HCC cells.

Conclusions

These results provide novel insight into the role of CYP2E1 in HCC and the tumor suppressor role of CYP2E1 can be attributed to its ability to manipulate Wnt/Dvl2/β-catenin pathway via inducing ROS accumulation, which provides a potential target for the prevention and treatment of HCC.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03396-6.

Real ambient particulate matter-induced lipid metabolism disorder: Roles of peroxisome proliferators-activated receptor alpha

A growing body of evidence associated particulate matter (PM) exposure with lipid metabolism disorders, yet, the underlying mechanism remains to be elucidated. Among the major lipid metabolism modulators, peroxisome proliferator-activated receptor (PPAR) alpha plays an important role. In the current study, an individually ventilated cage (IVC) system was used to expose C57/B6 mice to real-ambient PM for six weeks, with or without co-treatment of PPAR alpha agonist WY14,643. The general parameters, liver and adipose tissue pathology, serum lipids, metal deposition and lipid profile of liver were assessed. The results indicated that six weeks of real-ambient PM exposure induced dyslipidemia, including increased serum triglycerides (TG) and decreased high density lipoprotein cholesterol (HDL-C) level, along with steatosis in liver, increased size of adipocytes in white adipose tissue (WAT) and whitening of brown adipose tissue (BAT). ICP-MS results indicated increased Cr and As deposition in liver. Lipidomics analysis revealed that glycerophospholipids and cytochrome P450 pathway were most significantly affected by PM exposure. Several lipid metabolism-related genes, including CYP4A14 in liver and UCP1 in BAT were downregulated following PM exposure. WY14,643 treatment alleviated PM-induced dyslipidemia, liver steatosis and whitening of BAT, while enhancing CD36, SLC27A1, CYP4A14 and UCP1 expression. In conclusion, PPAR alpha pathway participates in PM-induced lipid metabolism disorder, PPAR alpha agonist WY14,643 treatment exerted protective effects on PM-induced dyslipidemia, liver steatosis and whitening of BAT, but not on increased adipocyte size of WAT.

Relationships among N,N-dimethylformamide exposure, CYP2E1 and TM6SF2 genes, and non-alcoholic fatty liver disease

OBJECTIVE

This study aimed to examine the relationships among N, N-dimethylformamide (DMF) exposure, cytochrome P4502E1 (CYP2E1) single nucleotide polymorphisms (SNPs) (rs2031920, rs3813867, rs6413432), transmembrane 6 superfamily member 2 (TM6SF2) SNP rs58542926 and non-alcoholic fatty liver disease (NAFLD).

METHODS

Baseline data were collected from participants who were then followed for 5 years in a prospective cohort study. The cohort initially consisted of 802 workers and ultimately included 660 people, all of whom underwent annual occupational health examinations from 2010 to 2015.

RESULTS

The above-threshold group (≥7.3 mg/m³ adjusted relative risk (RR)= 3.620, 95%CI 2.072-6.325) was significantly more likely to develop NAFLD than the below-threshold group (<7.3 mg/m³). The TM6SF2 SNP rs58542926 CT (adjusted RR=3.921, 95% CI 2.329-6.600, P = 0.000) and CT+TT (adjusted RR=4.385, 95% CI 2.639-7.287, P = 0.000) genotypes were risk factors for NAFLD, as compared with the TM6SF2 rs58542926 CC genotype. Each dose group (below-threshold group and above-threshold group) interacting with the genotype of TM6SF2 SNP rs58542926 had an adjusted RR from 7.764 (95% CI 3.272-18.420, P = 0.000) to 24.022 (95% CI 8.971-64.328, P = 0.000). The T allele of rs58542926 in the TM6SF2 gene may be a risk factor for susceptibility to DMF-induced NAFLD.

CONCLUSION

Polymorphisms of TM6SF2 SNP rs58542926 may play an important role in susceptibility to NAFLD after exposure to DMF.

TA allele of rs2070673 in the CYP2E1 gene is associated with lobular inflammation and nonalcoholic steatohepatitis in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIM

Cytochrome P450 2E1 (CYP2E1) plays a role in lipid metabolism, and by increasing hepatic oxidative stress and inflammation, the upregulation of CYP2E1 is involved in development of nonalcoholic steatohepatitis (NASH). We aimed to explore the relationship between CYP2E1-333A>T (rs2070673) and the histological severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 438 patients with biopsy-proven NAFLD. NASH was defined as NAFLD Activity Score ≥ 5 with existence of steatosis, ballooning, and lobular inflammation. CYP2E1-333A>T (rs2070673) was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Serum cytokines related to inflammation were measured by the Bio-plex 200 system to investigate possible mediating factors involved in the process.

RESULTS

The TA genotype of rs2070673 had a higher prevalence of moderate/severe lobular inflammation (27.6% vs 20.3% vs 13.3%, P < 0.01) and NASH (55.7% vs 42.4% vs 40.5%, P < 0.01) compared with the AA and TT genotypes, respectively. In multivariable regression modeling, the heterozygote state TA was associated with moderate/severe lobular inflammation (adjusted odds ratio: 2.31, 95% confidence interval 1.41-3.78, P < 0.01) or NASH (adjusted odds ratio: 1.82, 95% confidence interval 1.22-2.69, P < 0.01), independently of age, sex, common metabolic risk factors, and presence of liver fibrosis. Compared with no-NASH, NASH patients had significantly higher levels of serum interleukin-1 receptor antagonist, interleukin-18, and interferon-inducible protein-10 (IP-10), whereas only IP-10 was increased with the rs2070673 TA variant (P = 0.01). Mediation analysis showed that IP-10 was responsible for ~60% of the association between the rs2070672 and NASH.

CONCLUSIONS

The TA allele of rs2070673 is strongly associated with lobular inflammation and NASH, and this effect appears to be largely mediated by serum IP-10 levels.

CRISPR/Cas9-Mediated Whole Genomic Wide Knockout Screening Identifies Specific Genes Associated With PM2.5-Induced Mineral Absorption in Liver Toxicity

PM_2.5, also known as fine particles, refers to particulate matter with a dynamic diameter of ≦2.5 μm in air pollutants, that carries metals (Zn, Co, Cd) which can pass through the alveolar epithelium and enter the circulatory system and tissues. PM_2.5 can cause serious health problems, such as non-alcoholic fatty liver and hepatocellular carcinoma, although the underlying mechanisms of its toxic effect are poorly understood. Here, we exposed L02 cells to PM_2.5 and performed a pooled genome−wide clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) to assess loss of function and identify new potential PM_2.5targets. Enrichr and KEGG pathway analyses were performed to identify candidate genes associated with PM_2.5 toxicity. Results revealed that four key genes, namely ATPase Na+/K+ transporting subunit alpha 2 (ATP1A2), metallothionein 1M (MT1M), solute carrier family 6 members 19 (SLC6A19) and transient receptor potential cation channel subfamily V member 6 (TRPV6) were associated with PM_2.5 toxicity, mainly in regulating the mineral absorption pathway. Downregulating these genes increased cell viability and attenuated apoptosis in cells exposed to PM_2.5. Conversely, overexpressing TRPV6 exacerbated cell apoptosis caused by PM_2.5, while a reactive oxygen species (ROS) inhibitor N-acetyl-l-cysteine (NAC) alleviated PM_2.5-induced apoptosis. In conclusion, ATP1A2, MT1M, SLC6A19 and TRPV6 may be contributing to absorption of metals in PM_2.5 thereby inducing apoptosis mediated by ROS. Therefore, they hold potential as therapeutic targets for PM_2.5-related diseases.

Association of PM2.5 with Insulin Resistance Signaling Pathways on a Microfluidic Liver-Kidney Microphysiological System (LK-MPS) Device

Insulin resistance (IR) is a typical sign of metabolic dysregulation caused by fine particulate matter (PM_2.5), but the underlying signaling has not been clearly determined. Herein, a microfluidic liver-kidney microphysiological system (LK-MPS) is presented to assess the signaling pathways of IR generated by PM_2.5 at 200 μg/mL for 24 h. The LK-MPS device consisted of a biomimetic liver-kidney architecture and reconstructed two circulation paths: the liver metabolism-kidney excretion (LM-KE) and kidney excretion-liver metabolism (KE-LM), by which PM_2.5 is feasibly distributed in the two organs. Transmission electron microscopy (TEM) analysis revealed that PM_2.5 can embed in the cytoplasm and nuclei, undergo transport by vesicles, and lead to the destruction of mitochondria. Further comprehensive immunofluorescence, enzyme-linked immunosorbent assays (ELISAs) and untargeted metabolomic analyses confirmed that PM_2.5 disturbed the classic IRS-1/AKT signaling pathway (INSR, IRS-1, PI3K, AKT, GLUT2, GLUT4, and FOXO1 downregulated) and IR-related metabolic pathways: UDP-hexosamine (UDP-GlcNAc), gluconeogenesis (β-d-glucose 6-phosphate), and lipid biosynthesis (ceramide (Cer) and triacylglycerol (TG)) pathways, leading to the disorder of glucose levels. Collectively, these disorders aggravate hepatic and renal IR. Pearson's correlation coefficient test showed that elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), and metals (Ca, Co, and V) were negatively correlated to the dysregulated proteins (INSR, IRS-1, AKT, FOXO1, GLUT2, and GLUT4). These findings may partially explain IR-related signaling pathways triggered by PM_2.5.

Effects of total flavonoids from Eucommia ulmoides Oliv. leaves on polycystic ovary syndrome with insulin resistance model rats induced by letrozole combined with a high-fat diet

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommia ulmoides Oliv. leaves are the dry leaves of Eucommia ulmoides Oliv. Modern studies have shown that Eucommia ulmoides Oliv. leaves and its extracts have many pharmacological effects, such as regulating hypothalamus pituitary ovary (HPO) axis function, estrogen like effects, correcting insulin resistance (IR), regulating lipids, and reducing weight, which are consistent with the clinical manifestations in polycystic ovary syndrome (PCOS) patients. PCOS patients often have HPO axis disorder, low estrogen, high androgen, high IR complication rate, and obesity. Previous preclinical studies have shown that total flavonoids from Eucommia ulmoides Oliv. leaves (TFEL) can improve the imbalance in sex hormone secretion in perimenopausal animal models by regulating the function of the HPO axis. Thus, it is important to understand if flavonoids are the active parts of Eucommia ulmoides Oliv. leaves that interfere with polycystic ovary syndrome with insulin resistance (PCOS-IR), and determine the regulatory role they play in sex hormones and IR?

AIM OF THE STUDY

Investigate the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway in the ovary and kisspeptin/insulin like growth factor/leptin receptor1/androgen receptor (Kiss1/IGF-1/LEPR/AR) in the HPO axis to determine the mechanism of TFEL intervention in a rat model of PCOS-IR model rats.

MATERIALS AND METHODS

A rat model of PCOS-IR was established using a high-fat diet (49 d) combined with letrozole (1 mg/kg·d, for 28 d). Then, metformin (300 mg/kg·d) and TFEL (220 mg/kg·d, 110 mg/kg·d, and 55 mg/kg·d) were administered continuously for 21 days. At the end of the experiment, samples were taken and the related indexes were measured.

RESULTS

TFEL reduced the body weight, Lee's index, ovarian index, ovarian area and ovarian volume, increased serum E2, SHBG levels and ISI, decreased serum levels of T, LEP, INS, and FBG (whole blood), and reduced the HOMA-IR in rats with PCOS-IR. TFEL downregulate Kiss1, IGF-1, and AR in the arcuate nucleus of hypothalamus, and upregulate Kiss1, downregulate IGF-1 and AR in the pituitary gland, and upregulate Kiss1, downregulate IGF-1, LEPR, and AR in the ovary of rats with PCOS-IR. TFEL could downregulate p-IRS-1Ser307, upregulate IRS-1, p-IRS-1Tyr895, PI3Kp85α, p-PI3Kp85α, AKT, p-AKT, and GLUT4 in the ovary, and ameliorated histopathological changes in the ovary and pancreas of rats with PCOS-IR.

CONCLUSION

TFEL can inhibit ovarian hyperplasia, regulate disorders of glucose and lipid metabolism and improve the secretion of sex hormones, by regulating the expression of PI3K/AKT signaling pathway-related proteins in the ovary and Kiss1/IGF-1/LEPR/AR in the HPO axis.

Exploring the Protective Effects and Mechanism of Crocetin From Saffron Against NAFLD by Network Pharmacology and Experimental Validation

Background: Non-alcoholic fatty liver disease (NAFLD) is a burgeoning health problem but no drug has been approved for its treatment. Animal experiments and clinical trials have demonstrated the beneficial of saffron on NAFLD. However, the bioactive ingredients and therapeutic targets of saffron on NAFLD are unclear. Purpose: This study aimed to identify the bioactive ingredients of saffron responsible for its effects on NAFLD and explore its therapy targets through network pharmacology combined with experimental tests. Methods: Various network databases were searched to identify bioactive ingredients of saffron and identify NAFLD-related targets. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were conducted to enrich functions and molecular pathways of common targets and the STRING database was used to establish a protein-protein interaction network (PPI). The effect of crocetin (CCT) on NAFLD was evaluated in a mouse model of NAFLD by measuring the biomarkers of lipid, liver and renal function, oxidative stress, and inflammation. Liver histopathology was performed to evaluate liver injury. Nuclear factor erythroid-related factor (Nrf2) and hemeoxygenase-1 (HO-1) were examined to elucidate underlying mechanism for the protective effect of saffron against NAFLD. Results: A total of nine bioactive ingredients of saffron, including CCT, with 206 common targets showed therapeutic effects on NAFLD. Oxidative stress and diabetes related signaling pathways were identified as the critical signaling pathways mediating the therapeutic effects of the active bioactive ingredients on NAFLD. Treatment with CCT significantly reduced the activities of aspartate aminotransferase (AST), alanine transaminase (ALT), and the levels of total cholesterol (TC), triglyceride (TG), malondialdehyde (MDA), blood urea nitrogen (BUN), creatinine (CR), and uric acid (UA). CCT significantly increased the activities of superoxide dismutase (SOD), and catalase (CAT). Histological analysis showed that CCT suppressed high-fat diet (HFD) induced fat accumulation, steatohepatitis, and renal dysfunctions. Results of ELISA assay showed that CCT decreased the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and increased the expression of HO-1 and Nrf2. Conclusion: This study shows that CCT is a potential bioactive ingredient of saffron that treats NAFLD. Its mechanism of action involves suppressing of oxidative stress, mitigating inflammation, and upregulating Nrf2 and HO-1 expression.

Nutraceuticals with anti-inflammatory and anti-oxidant properties as intervention for reducing the health effects of fine particulate matter: Potential and Prospects

Air pollution, especially particulate matter pollution adversely affects human health. A growing pool of evidence has emerged which underscores the potential of individual-level nutritional interventions in attenuating the adverse health impact of exposure to PM2.5. Although controlling emission and reducing the overall levels of air pollution remains the ultimate objective globally, the sustainable achievement of such a target and thus consequent protection of human health will require a substantial amount of time and concerted efforts worldwide. In the meantime, smaller-scale individual-level interventions that can counter the inflammatory or oxidative stress effects triggered by exposure to particulate matter may be utilized to ameliorate the health effects of PM2.5 pollution. One such intervention is incorporation of nutraceuticals in the diet. Here, we present a review of the evidence generated from various in vitro, in vivo and human studies regarding the effects of different anti-inflammatory and antioxidant nutraceuticals in ameliorating the health effects of particulate matter air pollution. The studies discussed in this review suggest that these nutraceuticals when consumed as a part of the diet, or as additional supplementation, can potentially negate the cellular level adverse effects of exposure to particulate pollution. The potential benefits of adopting a non-pharmacological diet-based approach to air pollution-induced disease management have also been discussed. We argue that before a nutraceuticals-based approach can be used for widespread public adoption, further research, especially human clinical trials, is essential to confirm the beneficial action of relevant nutraceuticals and to explore the safe limits of human supplementation and the risk of side effects. Future research should focus on systematically translating bench-based knowledge regarding nutraceuticals gained from in-vitro and in-vivo studies into clinically usable nutritional guidelines.

New insight and potential therapy for NAFLD: CYP2E1 and flavonoids

Over the years, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased year by year; however, due to its complicated pathogenesis, there is no effective treatment so far. It is reported that Cytochrome P450 2E1 (CYP2E1) plays an indispensable role in the development of NAFLD, and numerous studies have shown that flavonoids have a hepatoprotective effect and can exert a beneficial effect on NAFLD by regulating the activity of CYP2E1. Therefore, flavonoids may become effective drugs for the treatment of NAFLD in the future. This prompted us to review the research progress of the pathological mechanism of NAFLD and the impact of CYP2E1 activity changes during the pathological process, and to summarize the protective effect of flavonoids against CYP2E1 activity.

In vitro simulated digestion and fecal fermentation of polysaccharides from loquat leaves: Dynamic changes in physicochemical properties and impacts on human gut microbiota

The aim of this study was to well understand the dynamic changes of physicochemical properties of polysaccharides from loquat leaves (LLP) during in vitro simulated saliva-gastrointestinal digestion and fecal fermentation and its related impacts on human gut microbiota. Results showed that the contents of reducing sugar of LLP slightly increased during the gastrointestinal digestion, and its molecular weight also slightly decreased, suggesting that LLP could be slightly degraded under the gastrointestinal digestion conditions. Moreover, during the fecal fermentation, the molecular weight of the indigestible LLP (LLP-I) significantly decreased, and the molar ratio of constituent monosaccharides of LLP-I, such as glucuronic acid, galacturonic acid, galactose, and arabinose, significantly changed, indicating that LLP-I could be degraded and consumed by human gut microbiota. Indeed, some beneficial bacteria such as Megasphaera, Megamonas, Bifidobacterium, Phascolarctobacterium, and Desulfovibrio significantly increased, suggesting that LLP-I could change the composition and abundance of gut microbiota. LLP-I could also promote the production of health-promoting short chain fatty acids. Results from this study are benefical to well understand the in vitro digestion and fecal fermentation behaviors of LLP, and LLP can be developed as a potential prebiotic in the functional food industry.

Flavonoids isolated from loquat (Eriobotrya japonica) leaves inhibit oxidative stress and inflammation induced by cigarette smoke in COPD mice: the role of TRPV1 signaling pathways

Chronic obstructive pulmonary disease (COPD) is a chronic, progressive lung disease with few successful treatments, and is strongly associated with cigarette smoking (CS). Since the novel coronavirus has spread worldwide seriously, there is growing concern that patients who have chronic respiratory conditions like COPD can easily be infected and are more prone to having severe illness and even mortality because of lung dysfunction. Loquat leaves have long been used as an important material for both pharmaceutical and functional applications in the treatment of lung disease in Asia, especially in China and Japan. Total flavonoids (TF), the main active components derived from loquat leaves, showed remarkable anti-inflammatory and antioxidant activities. However, their protective activity against CS-induced COPD airway inflammation and oxidative stress and its underlying mechanism still remain not well-understood. The present study uses a CS-induced mouse model to estimate the morphological changes in lung tissue. The results demonstrated that TF suppressed the histological changes in the lungs of CS-challenged mice, as evidenced by reduced generation of pro-inflammatory cytokines including interleukin 6 (IL-6), IL-1β, tumor necrosis factor α (TNF-α), nitric oxide (NO), and inducible nitric oxide synthase (iNOS) and diminished the protein expression of transient receptor potential vanilloid 1 (TRPV1). Moreover, TF also inhibited phosphorylation of IKK, IκB and NFκB and increased p-Akt. Interestingly, TF could inhibit CS-induced oxidative stress in the lungs of COPD mice. TF treatment significantly inhibited the level of malondialdehyde (MDA) and increased the activity of superoxide dismutase (SOD). In addition, TF markedly downregulated TRPV1 and cytochrome P450 2E1 (CYP2E1) and upregulated the expression of SOD-2, while the p-JNK level was observed to be inhibited in COPD mice. Taken together, our findings showed that the protective effect and putative mechanism of the action of TF resulted in the inhibition of inflammation and oxidative stress through the regulation of TRPV1 and the related signal pathway in lung tissues. It suggested that TF derived from loquat leaves could be considered to be an alternative or a new functional material and used for the treatment of CS-induced COPD.

Farnesoid X receptor mediates hepatic steatosis induced by PM2.5

Ambient particulate matter (PM) newly has been regarded as a conceivable hazard for public health. A large number of studies have described that PM, exceptionally PM2.5, is correlated with respiratory, cardiovascular, and metabolic diseases, etc. PM2.5-induced hepatocyte steatosis previously has been uncovered both in cellular and murine models. Nevertheless, less is known about the underlying mechanism. Here, we found that PM2.5 could cause the downregulation of farnesoid X receptor (FXR), a key transcription factor for lipid metabolism. FXR could regulate the accumulation of lipid droplets induced by PM2.5 in vitro. Moreover, FXR-/- mice were exposed to PM2.5 for 2 months to investigate the role of FXR in pathogenesis of PM2.5-induced hepatic steatosis in vivo. The results showed that exposure of wild-type (WT) mice to PM2.5 caused mild liver steatosis compared with the mice exposure to filtered air (FA). Furthermore, the content of triglyceride (TG) and total cholesterol (TC) was elevated in WT mice liver triggered by the inhalation of PM2.5. However, there was no statistical difference in TG and TC content between FXR-/- mice with and without PM2.5 exposure. Overall, our finding suggested FXR mediated PM2.5-induced hepatic steatosis.

Association between fine particle exposure and common test items in clinical laboratory: A time-series analysis in Changsha, China

Most studies on the health effects of PM_2.5 (fine particulate matter with diameter smaller than 2.5 μm) use indirect indicators, such as mortality and number of hospital visits. Recent research shows that biomarkers can also be used to evaluate the health effects of PM_2.5; however, these biomarkers are not very common. Clinical laboratories can provide a significant amount of test data that have been proven to have important diagnostic value. Therefore, we use big data analysis methods to find the associations between clinical laboratory common test items and PM_2.5 exposure. Data related to air pollution and meteorological information between 2014 and 2016 were obtained from the China National Environmental Monitoring Centre and the China National Meteorological Information Center. Additionally, data of 27 common test items from the same period were collected from Changsha Central Hospital. Primary analyses included a generalized additive model to analyze the associations between PM_2.5 concentration and common test items; the model was adjusted for time trends, weather conditions (temperature and humidity), and days of the week. Furthermore, we adjusted the effects of other air pollutants, such as PM₁₀, SO₂, NO₂, CO, and O₃. 17 items such as TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, LDL, WBC, K, Cl, Ca, TT, and FIB were significantly positively associated with PM_2.5 concentration (P< 0.05) and have concentration-response relationship. After adjusting the effect of PM₁₀+SO₂+NO₂+CO+O₃, TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, WBC, Cl, and Ca were still significantly associated with PM_2.5 concentration (P< 0.05). This current study suggested that clinical laboratory common test items may be used to assess and predict the health effects of PM_2.5 on the population.

AMPK activation ameliorates fine particulate matter-induced hepatic injury

Both the epidemiological and animal experimental studies have reported the association between PM_2.5 and respiratory, cardiovascular, and metabolic diseases. However, the study linking PM_2.5 and hepatic injury is few, and the relative mechanism has not been fully elucidated. Thirty-two 6-week-old male C57BL/6 mice were exposed to filtered air (FA) or concentrated PM_2.5 for 12 weeks using Shanghai Meteorological and Environmental Animal Exposure System ("Shanghai-METAS"), respectively. At week 11, the mice began to be treated with intraperitoneal injection of normal 0.9% saline or AMPK activator (AICAR). The mRNA levels of IL-6 and TNF-α, and protein expressions of AMPK, GLUT4, NF-κB, p38MAPK, ERK, and JNK in the liver and UCP-1 in brown adipose tissue (BAT) were measured. Meanwhile, histopathological examination both in the liver and BAT was performed to evaluate the histopathological changes. PM_2.5 exposure induced steatosis, hepatocyte ballooning, lobular and portal inflammation in the liver, and the brown adipocyte swelling in BAT. The results found that PM mice displayed higher IL-6, TNF-α, NF-κB, and JNK expression and lower AMPK, GLUT4, and UCP-1 when compared with FA mice. The AICAR injection upregulated the expressions of GLUT4 in the liver of PM-AIC mice when compared with the PM mice. However, there were no significant effects of AICAR on histopathological condition. The current study showed that ambient PM_2.5 exposure might induce the hepatic injury along with the lipid metabolism disorder in BAT. AMPK activation can ameliorate most of the harmful effects and might become the potential target for treating PM_2.5-induced hepatic injury.

Hepatoprotective and Anti-Oxidative Effects of Total Flavonoids From Qu Zhi Qiao (Fruit of Citrus Paradisi cv.Changshanhuyou) on Nonalcoholic Steatohepatitis In Vivo and In Vitro Through Nrf2-ARE Signaling Pathway

Nonalcoholic steatohepatitis (NASH) is a liver disease defined as the dynamic condition of hepatocellular injury during the progress of nonalcoholic fatty liver disease (NAFLD). Total flavonoids from the dry and immature fruits of Citrus Paradisi cv.Changshanhuyou (accepted species name: Citrus × aurantium L) (Qu Zhi Qiao, QZQ) are purified and named TFCH. This study was purposed to investigate and analyze the effect of TFCH on NASH model through Nuclear factor erythroid 2-related factor 2 (Nrf2)- antioxidant response elements pathway in vivo and in vitro. In vivo study was performed using male C57BL/6 mice fed with high fat diet 16 weeks for NASH model. After 7-week modeling, mice in TFCH-treated group were daily treated with intragastric administration of TFCH at 25 mg/kg, 50 mg/kg, 200 mg/kg, respectively, for successive 8 weeks. Histopathological and immunohistochemical analyses were conducted for evaluating severity of NASH-mice model and the effect of TFCH treatment. In vitro experiment was performed by using human LX-2 cells and cultured with Free fatty acid (FFA) (Oleic acid: palmitic: l: 0.5 mmol/L) for 24 h and then treated with TFCH at different concentrations (0, 25, 50, 100, 200 mg/ml) for 6 h,12 h, and 24 h. Anti-apoptosis effect of TFCH on LX-2 cells cultured with FFA was revealed by the CCK-8 assay. Lipid parameters and oxidative stress markers were measured in vivo and in vitro, results showed that TFCH dose-dependently and greatly increased the antioxidant ability and reduced the oxidative damage in NASH model. The protein expression of Nrf2 and the downstream target genes in mice liver and human LX-2 cells were tested by Western blot analysis to investigate the possible molecular mechanisms of TFCH. Our results indicated that TFCH up-regulated protein expression of these genes and have the significant influence in activating the Nrf2-ARE signaling pathway. This study shows Nrf2-ARE signaling pathway may provide novel therapeutic opportunities for NASH therapy in the future.

Polysaccharides from loquat (Eriobotrya japonica) leaves: Impacts of extraction methods on their physicochemical characteristics and biological activities

Impacts of hot water extraction (HWE), pressurized water extraction (PWE), high-speed shearing homogenization extraction, microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), ultrasound assisted enzymatic extraction, and ultrasound-microwave assisted extraction (UMAE) on physicochemical characteristics and bioactivities of polysaccharides from loquat (Eriobotrya japonica) leaves (LLPs) were investigated. Results showed that the degrees of esterification, contents of phenolics and uronic acids, constituent monosaccharides, apparent viscosities, and molecular weights of LLPs varied by different extraction methods. Bioactivities of LLPs were also significantly affected by different extraction methods. The high molecular weight and high degree of esterification of LLP-W and LLP-P extracted by HWE and PWE, respectively, might contribute to their strong binding capacities. The strong antioxidant activities and inhibitory effects on α-amylase and α-glucosidase were found in LLP-M and LLP-U extracted by MAE and UAE, respectively, which might be attributed to their contents of uronic acids, contents of total phenolics, and molecular weights. The low molecular weights and viscosities of LLP-U and LLP-UM extracted by UMAE might contribute to their strong prebiotic effects. These findings could provide scientific foundations for selecting appropriate extraction methods to obtain LLPs with desired bioactivities for applications in the pharmaceutical and functional food industries.

PM2.5 exposure induces age-dependent hepatic lipid metabolism disorder in female mice

Particulate matter exposure has been described to elevate the risk of lung and cardiovascular diseases. An increasing number of recent studies have indicated positive correlations between PM_2.5 (the fraction of airborne particles with an aerodynamic diameter less than 2.5 μm) exposure and the risk of liver diseases. However, research on the effects of PM_2.5 exposure on liver fat synthesis, secretion, and clearance mechanisms under normal diet conditions is limited, and whether these effects are age-dependent is largely unknown. Female C57BL/6 mice at different ages (4 weeks (4 w), 4 months (4 m), and 10 months (10 m)) were treated with 3 mg/kg body weight of PM_2.5 every other day for 4 weeks. Subsequently, the ultrastructural changes of liver, the expression of genes involved in oxidative damage and lipid metabolism in the liver were examined. Observation of hepatic ultrastructure showed more and larger lipid droplets in the livers of 4-week-old and 10-month-old mice exposed to PM_2.5. Further analysis showed that PM_2.5 exposure increased the expression of genes related to lipid synthesis, but decreased the expression of genes involved in lipid transport and catabolism in the livers of 10-month-old mice. Our findings suggest that exposure to PM_2.5 disrupts the normal metabolism of liver lipids and induces lipid accumulation in the liver of female mice in an age-dependent manner, with older mice being more susceptible to PM_2.5.

The preventive effect of phenolic-rich extracts from Chinese sumac fruits against nonalcoholic fatty liver disease in rats induced by a high-fat diet

The objective of this study is to investigate the preventive effect of phenolic-rich extracts from Chinese sumac (Rhus chinensis Mill.) fruits against NAFLD in rats induced by a high-fat diet and to clarify the underlying mechanisms.

Acetaminophen-Induced Liver Damage in Hepatic Steatosis

One of the most used painkillers is acetaminophen (APAP), which is safe at the right dose. However, several studies have described populations susceptible to APAP-induced liver damage, mainly in livers with steatosis. Thus, clinicians should consider the presence of obesity and other chronic liver diseases like nonalcoholic fatty liver disease (NAFLD) when indicating treatment with APAP. Liver damage from this drug is generated through its metabolite N-acetyl-p-benzoquinone imine, which is detoxified with glutathione (GSH). Prior depletion of GSH in steatotic hepatocytes plays a key role in APAP-induced hepatotoxicity in people with obesity and NAFLD. The knowledge about the damage to the liver or APAP in susceptible people like the obese and those with NAFLD is of great relevance for the sanitary sector because it would imply strategies of different therapeutic approach in such patients. This paper reviews the role of APAP in liver damage in the presence of obesity, NAFLD, and nonalcoholic steatohepatitis.

The Bioprotective Effects of Polyphenols on Metabolic Syndrome against Oxidative Stress: Evidences and Perspectives

Polyphenols are the general designation of various kinds of phytochemicals, mainly classified as flavonoids and nonflavonoids. Polyphenolic compounds have been confirmed to exhibit numerous bioactivities and potential health benefits both in vivo and in vitro. Dietary polyphenols have been shown to significantly alleviate several manifestations of metabolic syndrome, namely, central obesity, hypertension, dyslipidemia, and high blood sugar. This review is aimed at discussing the bioprotective effects and related molecular mechanisms of polyphenols, mainly by increasing antioxidant capacity or oxygen scavenging capacity. Polyphenols can exert their antioxidative activity by balancing the organic oxidoreductase enzyme system, regulating antioxidant responsive signaling pathways, and restoring mitochondrial function. These data are helpful for providing new insights into the potential biological effects of polyphenolic compounds and the development of future antioxidant therapeutics.

Polyphenol-rich Trapa quadrispinosa pericarp extract ameliorates high-fat diet induced non-alcoholic fatty liver disease by regulating lipid metabolism and insulin resistance in mice

In China, Trapa quadrispinosa (also called water caltrop) has long been used as a function food and folk medicine to treat diabetes mellitus for years. In the present study, the extract of T. quadrispinosa pericarp (TQPE) which mainly contains hydrolysable tannins was prepared to investigate the potential therapeutic action in non-alcoholic fatty liver disease (NAFLD) mice induced by high fat-diet (HFD). After the administration of TQPE (15, 30 mg/kg/day) for 8 weeks, the increased weight of body and liver were significantly suppressed. TQPE also ameliorated liver lipid deposition and reduced lipids parameters of blood in mice. Moreover, TQPE attenuated oxidative stress and showed a hepatoprotective effect in mice. TQPE was also found to decrease the value of homeostatic model assessment for insulin resistance. In addition, TQPE administration increased the phosphorylation of AMP-activated protein kinase (AMPK) and Acetyl-CoA carboxylase (ACC) and inhibited sterol regulatory element-binding protein (SREBP) in the liver tissue. Meanwhile, TQPE elevated insulin receptor substrate-1 (IRs-1) and protein kinase B (Akt) phosphorylation. These results reflected that, as a nature product, TQPE is a potential agent for suppressing the process of NAFLD via regulation of the AMPK/SREBP/ACC and IRs-1/Akt pathways.

Hydroxytyrosol prevents PM2.5-induced adiposity and insulin resistance by restraining oxidative stress related NF-κB pathway and modulation of gut microbiota in a murine model

Exposure to fine particular matter (≤2.5 μM, PM_2.5) contributes to increased risk of obesity and type 2 diabetes. Hydroxytyrosol (HT), a simple polyphenol found in virgin olive oil, is considered to be beneficial for cardiovascular and metabolic disorders. The current study determined whether HT could improve PM_2.5-induced adiposity and insulin resistance (IR), and explored the underlying mechanisms. Fifteen adult female C57BL/6j mice on a chow diet were randomly divided into three groups receiving (1) sterile PBS, (2) PM_2.5 suspended in sterile PBS (1 mg/mL) and (3) PM_2.5+HT (50 mg/kg/day). PM_2.5/PBS exposure was administered by oropharynx instillation every other day and HT supplementation was achieved by gavage every day. Four-week PM_2.5 exposure did not affect body weight, but significantly increased visceral fat mass. The abdominal adiposity coincided with adipocyte hypertrophy and proliferation in visceral white adipose tissue (WAT), as well as decreased metabolic activity in brown adipose tissue and subcutaneous WAT. PM_2.5 enhanced the oxidative stress by diminishing antioxidant enzyme activities in liver and serum, whereas contents of 4-hydroxynonenal (4-HNE), malondialdehyde (MDA) levels in liver and serum were elevated. These changes were accompanied by macrophage infiltration and activation of NF-κB pathway in the liver. Moreover, PM_2.5 exposure led to glucose intolerance and insulin insensitivity, impaired hepatic glycogenesis, and decreased insulin-stimulated Akt phosphorylation in peripheral tissues. Importantly, HT treatment prevented PM_2.5-induced visceral adipogenesis, oxidative stress, hepatic inflammation and NF-κB activation, systemic and peripheral IR. In vitro, after HepG2 cells were incubated with PM_2.5 (0, 5, 25, 50, 100 and 200 μg/mL), reduced glutathione depletion and 4-HNE, 8-hydroxy-2'-deoxyguanosine, MDA increment in a dose-dependent manner were observed; likewise, insulin-stimulated glucose uptake decreased in a dose-dependent manner. Further, with antioxidant NAC and NF-κB inhibitor PDTC, we confirmed that HT attenuated PM_2.5-induced IR through restraining NF-κB activation evoked by oxidative stress. In addition, HT could expand gut microbiota richness, reduce pathogenic bacteria and accommodate the microbial architecture in PM_2.5-exposed mice, which were correlated with parameters of adiposity, oxidative stress and glycometabolism. HT could effectively correct imbalanced oxidative stress triggered by PM_2.5, in turn ameliorated NF-κB pathway and insulin signaling. Gut microbiota may mediate the actions of HT.

Dietary diisononylphthalate contamination induces hepatic stress: a multidisciplinary investigation in gilthead seabream (Sparus aurata) liver

In this study, adult gilthead seabream (Sparus aurata) were exposed for 21 days to Di-iso-nonylphthalte (DiNP at 15 and 1500 μg kg^-1 bw day^-1) via the diet. This plastic additive has been recently introduced to replace the di-(2-ethylhexyl)phthalate, the toxicity of which has been demonstrated conclusively both in vivo and in vitro trials. An analysis of a set of biomarkers involved in stress and immune response provides evidence of hepatic toxicity by DiNP in the present study. Both hsp70 and gr mRNA levels were upregulated significantly by DiNP, while plasma cortisol increased only in fish fed with the lowest DiNP dose. The oxidative stress markers g6pdh, glut red, gpx1 and CAT were upregulated by DiNP; gst mRNA was induced by the high dose and gck mRNA was downregulated significantly by the low dose. The mRNA levels of genes involved in the immune response, such as pla2, 5-lox, tnfa and cox2, were upregulated significantly only by the high dose of DiNP, while il1 mRNA increases in both doses. These molecular evidences were complemented with features obtained by Fourier Transform Infrared Imaging (FTIRI) analysis regarding the hepatic distribution of the main biological macromolecules. The FTIRI analysis showed an alteration of biochemical composition in DiNP samples. In particular, the low dose of DiNP induced an increase of saturated and unsaturated lipids and phosphorylated proteins, and a decrease of glycogen levels. The levels of caspase did not change significantly in the study, suggesting that DiNP does not activate apoptosis. Finally, the results also suggested the onset of hepatic oxidative stress and the activation of immune response, adding new knowledge to the already described hepatic DiNP toxicity.

Protective effect and mechanism of Qiwei Tiexie capsule on 3T3-L1 adipocytes cells and rats with nonalcoholic fatty liver disease by regulating LXRα, PPARγ, and NF-κB-iNOS-NO signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Qiwei Tiexie capsule (QWTX) is a representative prescription of Tibetan medicine, which is widely used for long-term treatment of chronic liver disease and nonalcoholic fatty liver disease (NAFLD).

AIM OF THE STUDY

This study explored the effects and mechanism of QWTX on 3T3-L1 adipocytes and NAFLD.

MATERIALS AND METHODS

The 3T3-L1 preadipocytes and NAFLD rat model were used in the study. In 3T3-L1 cells, the cytotoxicity of QWTX was tested by CKK-8, and glucose uptake and fat acid oxidation were assessed by 2-deoxy-D-[³H] glucose and [1-¹⁴C] palmitic acid, respectively. The expression levels of carnitine palmitoyltransferase-1 (CPT-1), liver X receptor α (LXRα), peroxisome proliferator-activated receptor (PPAR) γ, inducible nitric oxide synthase (iNOS), ikappa B α (IκBα), and AKT were determined by PCR and western blot. NAFLD was established by the administration of fat emulsion and sucrose for 9 weeks. The effects of QWTX on lipid metabolism, liver function, and hepatic morphology were observed in NAFLD rats by HE and transmission electron microscope. Serum level of nitric oxide (NO) and fee fatty acid (FFA), superoxide dismutase (SOD) and malondialdehyde (MDA) contents in the liver, as well as the expression levels of Cytochrome P450 2E1 (CYP2E1), NF-κB, monocyte chemoattractant protein 1 (MCP-1), CPT-1, LXRα, PPARα, PPARβ/δ, PPARγ, and iNOS were all detected.

RESULTS

QWTX showed no cell cytotoxicity in 3T3-L1 preadipocyte cells, and increased the ¹⁴CO₂ production rate to 4.15, which indicated the reducing the fatty accumulation. In NAFLD, QWTX attenuated liver steatosis, fat vacuoles and inflammation from the HE staining and electron micrograph tests. For the oxidative stress biomarkers, serum FFA level was reduced and serum NO level was enhanced after QWTX treatment. In liver tissue, SOD was decreased and MDA was significantly increased in NAFLD, and both of them were restored by QWTX. NF-κB and CYP2E1 were also upregulated in NAFLD, while downregulated by QWTX. Downregulation of LXRα, PPARγ and iNOS by QWTX were both observed in the 3T3-L1 adipocytes and NAFLD model.

CONCLUSIONS

QWTX protected the liver injury in differentiated 3T3-L1 adipocytes and NAFLD by regulating the LXRα, PPARγ, and NF-κB-iNOS-NO signal pathways.

Glucose Homeostasis following Diesel Exhaust Particulate Matter Exposure in a Lung Epithelial Cell-Specific IKK2-Deficient Mouse Model

BACKGROUND

Pulmonary inflammation is believed to be central to the pathogenesis due to exposure to fine particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text]). This central role, however, has not yet been systemically examined.

OBJECTIVE

In the present study, we exploited a lung epithelial cell-specific inhibitor [Formula: see text] kinase 2 (IKK2) knockout mouse model to determine the role of pulmonary inflammation in the pathophysiology due to exposure to diesel exhaust particulate matter (DEP).

METHODS

[Formula: see text] (lung epithelial cell-specific IKK2 knockout, KO) and [Formula: see text] (wild-type, tgWT) mice were intratracheally instilled with either vehicle or DEP for 4 months, and their inflammatory response and glucose homeostasis were then assessed.

RESULTS

In comparison with tgWT mice, lung epithelial cell-specific IKK2-deficient mice had fewer DEP exposure-induced bronchoalveolar lavage fluid immune cells and proinflammatory cytokines as well as fewer DEP exposure-induced circulating proinflammatory cytokines. Glucose and insulin tolerance tests revealed that lung epithelial cell-specific IKK2 deficiency resulted in markedly less DEP exposure-induced insulin resistance and greater glucose tolerance. Akt phosphorylation analyses of insulin-responsive tissues showed that DEP exposure primarily targeted hepatic insulin sensitivity. Lung epithelial cell-specific IKK2-deficient mice had significantly lower hepatic insulin resistance than tgWT mice had. Furthermore, this difference in insulin resistance was accompanied by consistent differences in hepatic insulin receptor substrate 1 serine phosphorylation and inflammatory marker expression.

DISCUSSION

Our findings suggest that in a tissue-specific knockout mouse model, an IKK2-dependent pulmonary inflammatory response was essential for the development of abnormal glucose homeostasis due to exposure to DEP. https://doi.org/10.1289/EHP4591.