Imbalanced inflammatory response in subchronic arsenic-induced liver injury and the protective effects of Ginkgo biloba extract in rats: Potential role of cytokines mediated cell-cell interactions

Copper, Iron, Cadmium, and Arsenic, All Generated in the Universe: Elucidating Their Environmental Impact Risk on Human Health Including Clinical Liver Injury

Humans are continuously exposed to various heavy metals including copper, iron, cadmium, and arsenic, which were specifically selected for the current analysis because they are among the most frequently encountered environmental mankind and industrial pollutants potentially causing human health hazards and liver injury. So far, these issues were poorly assessed and remained a matter of debate, also due to inconsistent results. The aim of the actual report is to thoroughly analyze the positive as well as negative effects of these four heavy metals on human health. Copper and iron are correctly viewed as pollutant elements essential for maintaining human health because they are part of important enzymes and metabolic pathways. Healthy individuals are prepared through various genetically based mechanisms to maintain cellular copper and iron homeostasis, thereby circumventing or reducing hazardous liver and organ injury due to excessive amounts of these metals continuously entering the human body. In a few humans with gene aberration, however, liver and organ injury may develop because excessively accumulated copper can lead to Wilson disease and substantial iron deposition to hemochromatosis. At the molecular level, toxicities of some heavy metals are traced back to the Haber Weiss and Fenton reactions involving reactive oxygen species formed in the course of oxidative stress. On the other hand, cellular homeostasis for cadmium and arsenic cannot be provided, causing their life-long excessive deposition in the liver and other organs. Consequently, cadmium and arsenic represent health hazards leading to higher disability-adjusted life years and increased mortality rates due to cancer and non-cancer diseases. For unknown reasons, however, liver injury in humans exposed to cadmium and arsenic is rarely observed. In sum, copper and iron are good for the human health of most individuals except for those with Wilson disease or hemochromatosis at risk of liver injury through radical formation, while cadmium and arsenic lack any beneficial effects but rather are potentially hazardous to human health with a focus on increased disability potential and risk for cancer. Primary efforts should focus on reducing the industrial emission of hazardous heavy metals.

The mitochondria-targeted antioxidant MitoQ ameliorates inorganic arsenic-induced DCs/Th1/Th2/Th17/Treg differentiation partially by activating PINK1-mediated mitophagy in murine liver

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.

Promotion of transcription factor EB-dependent autophagic process by curcumin alleviates arsenic-caused lung oxidative stress and inflammation in mice

Arsenic is a human carcinogen widely distributed in the environment, and arsenic exposure from drinking water has received widespread attention as a global public health problem. Curcumin is a natural bioactive substance with high efficiency and low toxicity extracted from turmeric, which has a variety of biological properties such as antioxidation, anti-inflammation, anticancer, and immuno-modulatory activities. Curcumin is widely used in daily life as a food additive and dietary supplement. However, its protective effects in lung injuries by chronic arsenic exposure orally remain unexplored. In this study, curcumin treatment not only significantly accelerated arsenic elimination and improved lung tissue morphology, but also decreased arsenic-generated ROS by activating Nrf2 and its down-stream antioxidants. Further, curcumin alleviated inflammatory changes in mice exposed to arsenic for 6 and 12 weeks, as manifested by lung MPO levels, total protein and cellular levels in bronchoalveolar lavage fluid (BALF), serum IL-4 levels, and MAPK/NF-κB expression in lung tissue. Notably, our study also confirmed that curcumin could promote the expression and nuclear translocation of the transcription factor EB (TFEB), as well as activate TFEB-regulated autophagy in lung tissue of arsenic-treated mice, accompanied by inhibition of the AKT-mTOR signaling pathway. Overall, our study here suggests that natural bioactive compound curcumin could alleviate arsenic-induced pulmonary oxidative stress and inflammation in vivo, which is closely related to enhanced TFEB activity and induction of the autophagic process.

Rosa roxburghii Tratt juice inhibits NF-κB and increases IL-2 to alleviates the Foxp3-mediated Tregs imbalance in the peripheral blood of arseniasis patients

Arsenic can cause immune inflammation, which is the basis of arsenic-induced damage to multiple organs and systems. Forkhead box P3 (Foxp3)-labelled CD4+CD25+ regulatory T cells (Tregs) play an essential role in maintaining immune homeostasis. Nuclear factor-κb (NF-κB) and Interleukin-2 (IL-2) are critical regulators of Foxp3. Rosa roxburghii Tratt (RRT) is an edible medicinal plant with anti-inflammation effects. In this study, a control group (n = 41) and an arseniasis group (n = 209) were recruited, and screened subjects from the arseniasis patients for RRTJ (n = 46) or placebo (n = 43) to explore the possible mechanism by which RRT alleviates immune inflammation. The results indicated that RRTJ can inhibits NF-κB and increases IL-2, and alleviates the Foxp3-mediated Tregs imbalance in the peripheral blood of arseniasis patients. In summary, these findings suggest a novel intervention or therapeutic target for immune inflammation in arseniasis patients and provide new evidence that RRTJ inhibits immune inflammation.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01384-0.

Drug-induced liver injury and anti-hepatotoxic effect of herbal compounds: a metabolic mechanism perspective

BACKGROUND

Drug-induced liver injury (DILI) is the most challenging and thought-provoking liver problem for hepatologists owing to unregulated medication usage in medical practices, nutritional supplements, and botanicals. Due to underreporting, analysis, and identification issues, clinically evaluated medication hepatotoxicity is prevalent yet hard to quantify.

PURPOSE

This review's primary objective is to thoroughly compare pharmaceutical drugs and herbal compounds that have undergone clinical trials, focusing on their metabolic mechanisms contributing to the onset of liver illnesses and their hepatoprotective effects.

METHODS

The data was gathered from several online sources, such as PubMed, Scopus, Google Scholar, and Web of Science, using appropriate keywords.

RESULTS

The prevalence of conventional and herbal medicine is rising. A comprehensive understanding of the metabolic mechanism is necessary to mitigate the hepatotoxicity induced by drugs and facilitate the incorporation or substitution of herbal medicine instead of pharmaceuticals. Moreover, pre-clinical pharmacological research has the potential to facilitate the development of natural products as therapeutic agents, displaying promising possibilities for their eventual clinical implementation.

CONCLUSIONS

Acetaminophen, isoniazid, rifampicin, diclofenac, and pyrogallol have been identified as the most often reported synthetic drugs that produce hepatotoxicity by oxidative stress, inflammation, apoptosis, and fibrosis during the last several decades. Due to their ability to downregulate many factors (such as cytokines) and activate several enzyme/enzyme systems, herbal substances (such as Gingko biloba extract, curcumin, resveratrol, and silymarin) provide superior protection against harmful mechanisms which induce hepatotoxicity with fewer adverse effects than their synthetic counterparts.

Ginkgo Biloba Extract Can Antagonize Subchronic Arsenite Exposure-Induced Hepatocyte Senescence by Inhibiting Oxidative Damage and Inflammation in Rats

A growing body of evidence suggests that long-term arsenic exposure can induce liver injury. Our previous studies have demonstrated that liver injury occurs in arsenic-poisoning patients and arsenic-exposed rats. However, therapeutic targets are still unclear, and there is a lack of effective drugs. This study aimed to investigate the effects of sodium arsenite (arsenite) exposure on hepatocyte senescence and the intervention effect of ginkgo biloba extract in rats. In this study, 24 male Sprague-Dawley rats (weighing 180-200 g) were randomized into three groups. The control group received a normal diet, and the arsenic-exposed group was given 10 mg/L arsenite for 3 months by free drinking along with a normal diet. The ginkgo biloba extract treatment group was consecutively administered EGb761 (10 mg/kg, by gavage) for 1 month following 2 months of arsenite exposure. Our results showed that exposure to 10 mg/L arsenite induced narrowing of the hepatic sinus space, enlargement of hepatocytes, and increased multinucleated hepatocytes and inflammatory cell infiltration in rat liver tissue compared with the normal control group. Moreover, 10 mg/L arsenite also caused abnormal expression of inflammation-related indices (IL1-β, IL-6, TNF-α), oxidative damage-related indices (SOD, MDA, GPx), and senescence-related proteins (p16, p-p53, E2F1). EGb761 could effectively reduce the pathological damage of liver tissue and antagonize the abnormal expression of liver tissue inflammation and oxidative damage-related indices as well as cellular senescence-related proteins caused by arsenite exposure. Notably, EGb761 reduced the accumulation of arsenic in rat liver tissues. These results suggested that EGb761 could effectively alleviate subchronic arsenic exposure-induced senescence of hepatocytes, which may be achieved partially through inhibiting inflammation and oxidative damage in rats. This study may provide a new therapeutic target for arsenic-induced liver injury.

Metformin alleviates sodium arsenite-induced hepatotoxicity and glucose intolerance in mice by suppressing oxidative stress, inflammation, and apoptosis

BACKGROUND

Epidemiological studies have shown that exposure to sodium arsenite (NaAsO2) causes diabetes and hepatotoxicity. Metformin (MET), an oral hypoglycemic agent, has long been used in diabetes therapy. In addition, MET has been shown to have hepatoprotective effects. In this study, we investigated the effects of MET on NaAsO2-induced hepatotoxicity and glucose intolerance in mice.

METHODS

Mice were divided into four groups: Groups I and II received distilled water and NaAsO2 (10 mg/kg, p.o.) for five weeks, respectively. Groups III and IV were treated with NaAsO2 (10 mg/kg, p.o.) for three weeks, followed by MET (125 and 250 mg/kg, p.o.) for the last two weeks before NaAsO2. A glucose tolerance test was performed on day 35. The serum and tissue parameters were also evaluated.

RESULTS

Histopathological examination revealed NaAsO2-induced liver and pancreatic damage. NaAsO2 caused hyperglycemia, glucose intolerance, and a significant increase in liver function enzymes. Administration of NaAsO2 significantly reduced hepatic superoxide dismutase, catalase, glutathione peroxidase, and total thiol levels and increased the content of reactive thiobarbituric acid substances. In addition, it led to an increase in liver nitric oxide levels and protein expression of tumor necrosis factor-α, nuclear factor kappa B, and cysteine-aspartic proteases-3. In contrast, treatment with MET (250 mg/kg) significantly improved NaAsO2-induced biochemical and histopathological changes.

CONCLUSION

Our findings suggest that the significant effects of MET against NaAsO2-induced hepatotoxicity and glucose intolerance may be exerted via the regulation of oxidative stress, followed by suppression of inflammation and apoptosis.

Reduced Peripheral Blood Mitochondrial DNA Copy Number as Identification Biomarker of Suspected Arsenic-Induced Liver Damage

Arsenic (As) can cause liver damage and liver cancer and is capable of seriously affecting human health. Therefore, it is important to identify biomarkers of arsenic-induced liver damage. Mitochondria are key targets of hepatotoxicity caused by arsenic. The mitochondrial DNA copy number (mtDNAcn) is the number of mitochondrial DNA (mtDNA) copies in the genome. mtDNA is vulnerable to exogenous chemical attacks, thus causing mtDNAcn to change after exposure to environmental pollutants. Therefore, mtDNAcn can serve as a potential marker to identify and assess the risk of diseases caused by exposure to environmental pollutants. In this study, we selected 272 arsenicosis patients (155 cases without liver damage and 117 cases with liver damage) and 218 participants not exposed to arsenic (155 cases without liver damage and 63 cases with liver damage) as subjects to investigate the correlation between peripheral blood mtDNAcn and arsenic-induced liver damage, as well as the ability of peripheral blood mtDNAcn to identify and assess the risk of arsenic-induced liver damage. Peripheral blood mtDNAcn in patients with arsenic-induced liver damage is significantly decreased and negatively correlated with serum ALT, AST, and GGT levels. The decrease of peripheral blood mtDNAcn was associated with an increased risk of arsenic-induced liver damage. The receiver operating characteristic (ROC) curve analysis indicated that peripheral blood mtDNAcn could specifically identify patients with liver damage in the arsenicosis group. The decision tree C5.0 model was established to identify arsenicosis in all patients with liver damage. Peripheral blood mtDNAcn was included in the model and played the most important role in the identification of arsenic-induced liver damage. This study provided a basis for the identification and evaluation of arsenic-induced liver damage by peripheral blood mtDNAcn, indicating that peripheral blood mtDNAcn is expected to be a potential biomarker of arsenic-induced liver damage, and provides clues for exploring the mechanism of arsenic-induced liver damage from mitochondria damage.

A Novel Quinazoline Derivative Prevents and Treats Arsenic-Induced Liver Injury by Regulating the Expression of RecQ Family Helicase

Arsenic is a carcinogenic metalloid toxicant widely found in the natural environment. Acute or prolonged exposure to arsenic causes a series of damages to the organs, mainly the liver, such as hepatomegaly, liver fibrosis, cirrhosis, and even hepatocellular carcinoma. Therefore, it is imperative to seek drugs to prevent arsenic-induced liver injury. Quinazolines are a class of nitrogen heterocyclic compounds with biological and pharmacological effects in vivo and in vitro. This study was designed to investigate the ameliorating effects of quinazoline derivatives on arsenic-induced liver injury and its molecular mechanism. We investigated the mechanism of the quinazoline derivative KZL-047 in preventing and ameliorating arsenic-induced liver injury in vitro by cell cycle and apoptosis. We performed real-time fluorescence quantitative polymerase chain reaction (qPCR) and Western blotting combined with molecular docking. In vivo, the experiments were performed to investigate the mechanism of KZL-047 in preventing and ameliorating arsenic-induced liver injury using arsenic-infected mice. Physiological and biochemical indices of liver function in mouse serum were measured, histopathological changes in liver tissue were observed, and immunohistochemical staining was used to detect changes in the expression of RecQ-family helicases in mouse liver tissue. The results of in vitro experiments showed that sodium arsenite (SA) inhibited the proliferation of L-02 cells, induced apoptosis, blocked the cell cycle at the G1 phase, and decreased the expression of RecQ family helicase; after KZL-047 treatment in arsenic-induced L-02 cells, the expression of RecQ family helicase was upregulated, and the apoptosis rate was slowed, leading to the restoration of the cell viability level. KZL-047 inhibited arsenic-induced oxidative stress, alleviated oxidative damage and lipid peroxidation in vivo, and ameliorated arsenic toxicity-induced liver injury. KZL-047 restored the expression of RecQ family helicase proteins, which is consistent with the results of in vitro studies. In summary, KZL-047 can be considered a potential candidate for the treatment of arsenic-induced liver injury.

Depletion of S-adenosylmethionine induced by arsenic exposure is involved in liver injury of rat through perturbing histone H3K36 trimethylation dependent bile acid metabolism

Long-term exposure to arsenic, a common environmental pollutant, can induce various types of liver injury, but the mechanism and treatment measures remain unclear. This study constructed a rat model of arsenic-induced liver injury, with methyl group donor S-adenosylmethionine (SAM) supplementation and Rosa roxburghii Tratt juice intervention, to explore the epigenetic mechanism and intervention method of arsenic-induced liver injury from the perspective of hepatic bile acid metabolism. The results showed that arsenic exposure induced the accumulation of total bile acids (TBA) in the liver and serum of rats, and the abnormalities in liver function and liver histopathology. Arsenic reduced histone H3K36 trimethylation (H3K36me3) in the liver via consuming methyl group donor SAM. The reduction of H3K36me3 was involved in arsenic-induced bile acid accumulation by inhibiting the transcription of negative feedback regulators Fxr and Fgfr4 for hepatic bile acid synthesis. SAM supplementation reversed arsenic-induced bile acid accumulation and liver injury by reactivating H3k36me3-dependent transcription of Fxr and Fgfr4. Moreover, this study found that Rosa roxburghii Tratt juice could rescue arsenic-induced SAM consumption, recover H3K36me3-dependent negative feedback regulation of hepatic bile acid synthesis, and alleviate arsenic-induced bile acid accumulation and liver injury. In conclusion, arsenic exposure perturbed H3K36me3-dependent hepatic bile acid metabolism via depleting SAM, thereby inducing hepatic bile acid accumulation and liver injury, which was ameliorated by the supporting effect of Rosa roxburghii Tratt juice on SAM. This study contributes to understanding the mechanism of arsenic-induced liver injury from the perspective of SAM-dependent epigenetics, providing new insight into its prevention and treatment.

C/EBPβ-TFAM-Mediated NLRP3 Inflammasome Activation Contributes to Arsenic-Induced Rat Kidney Injury

Compelling evidence has demonstrated that arsenic (As) exposure is associated with kidney injuries. Given that inflammatory responses and immune imbalances are the root causes of several kidney diseases, this study investigated the potential mechanisms underlying NLRP3 inflammasome activation in As-induced kidney injury. A rat model of sub-chronic As exposure was established via oral administration of NaAsO2. The results revealed that urinary β-2-microglobulin (β2-MG), N-acetyl-β-D-glucosidase (NAG) and albumin (ALB) were increased in the As-exposed group, reflecting kidney impairment. Moreover, significant glomerular vacuole-like changes, tubular dilatation and inflammatory cell infiltration were observed. Meanwhile, the expression levels of neutrophil gelatinase-associated lipocalin (NGAL), IL-1β and IL-18 were enhanced in the kidney tissues of As-treated rats. Further, increased expression of NLRP3, ASC and caspase-1, which are NLRP3 inflammasome-associated proteins, were observed in the kidney tissues of rats in the As-treated groups. The expression levels of the NLRP3 upstream regulators C/EBPβ and TFAM were also elevated. These findings suggest that sub-chronic As exposure triggers inflammatory responses in rat kidney tissue and impairs kidney function. The underlying mechanisms may be related to the C/EBPβ-TFAM pathway and activation of the NLRP3 inflammasome pathway.

Inhibition of Histone H3K18 Acetylation-Dependent Antioxidant Pathways Involved in Arsenic-Induced Liver Injury in Rats and the Protective Effect of Rosa roxburghii Tratt Juice

Arsenic is a common environmental toxicant. Long-term arsenic exposure can induce various types of liver injury, but the underlying mechanism remains unclear, so effective prevention and treatment measures are unknown. This study aims to explore the mechanism of arsenic-induced rat liver injury based on the histone H3K18 acetylation-dependent antioxidant pathway and to identify the role of a medicinal and edible resource, Rosa roxburghii Tratt juice, in combating it. Hepatic steatosis and inflammatory cell infiltration were observed in rats exposed to different doses of NaAsO₂ using histopathological measurement. Increased 8-OHdG and MDA in liver tissue corroborated hepatic oxidative damage. We further found that a reduction in H3K18ac in the liver showed a dose-response relationship, with an increase in the NaAsO₂ treatment dose, and it was remarkably associated with increased 8-OHdG and MDA. The results of ChIP-qPCR identified that the decreased enrichment of H3K18ac in promoters of the Hspa1a and Hspb8 genes culminated in the inhibition of the genes' expression, which was found to be involved in the aggravation of hepatic oxidative damage induced by arsenic. Notably, Rosa roxburghii Tratt juice was found to reduce 8-OHdG and MDA in the liver, thereby alleviating the histopathological lesions induced by arsenic, which was modulated by recovering the H3K18ac-dependent transcriptional activation of the Hspa1a and Hspb8 genes. Taken together, we provide a novel epigenetics insight into clarifying the mechanism of arsenic-induced liver injury and its rescue by Rosa roxburghii Tratt juice.

Diosmin exerts hepatoprotective and antihyperglycemic effects against sodium arsenite-induced toxicity through the modulation of oxidative stress and inflammation in mice

BACKGROUND

Chronic exposure to high concentrations of inorganic arsenic (NaAsO₂) in drinking water is related to an increase in the risk of liver toxicity and diabetes. Diosmin has various pharmacological properties, including antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effects of diosmin on diabetes and hepatotoxicity caused by NaAsO₂.

METHODS

Sixty male 8-week-old NMRI mice, weighing 25 ± 2 g, were randomly selected and put into six groups. The control (Group 1) was treated orally with distilled water, group 2 was treated with diosmin (100 mg/kg, p.o), group 3 received NaAsO₂ (10 mg/kg, p.o), and groups 4, 5, 6 received diosmin (25, 50, 100 mg/kg, p.o), respectively and NaAsO₂ (10 mg/kg, p.o). After 29 days, fasting blood sugar (FBS) measurement and glucose tolerance test were done. The mice were sacrificed on day 31, and blood and tissue (liver and pancreas) samples were taken. Then, serum and tissue samples were studied for biochemical and histological evaluations.

RESULTS

The results demonstrated that diosmin ameliorated glucose intolerance and decreased FBS compared to the NaAsO₂ group. Diosmin (50 and 100 mg/kg) improved the serum factors of liver function (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) in the groups receiving NaAsO₂. Moreover, increased levels of nitric oxide, tumor necrosis factor-alpha, and thiobarbituric acid reactive substances in liver tissue induced by NaAsO₂ were diminished by diosmin treatment. Administration of diosmin increased total thiol and enzymatic activities of catalase, superoxide dismutase, and glutathione peroxidase in liver tissue. Furthermore, treatment with diosmin reduced the increase in protein amount of Sirtuin 3 and nuclear factor kappa B in the groups receiving NaAsO₂. Also, the liver and pancreas histological lesions induced by NaAsO₂ were attenuated by diosmin treatment.

CONCLUSION

Diosmin has a preventive effect against hepatotoxicity and diabetes induced by NaAsO₂ in mice through its antioxidant and anti-inflammatory properties.

Hyperphosphorylation of EGFR/ERK signaling facilitates long-term arsenite-induced hepatocytes epithelial-mesenchymal transition and liver fibrosis in sprague-dawley rats

Arsenic is a well known environmental hazardous material, chronic arsenic exposure results in different types of liver damage. Among them, liver fibrosis has become a research hotspot because of its reversibility, while the underlying mechanism is still unclear. Previous studies revealed that EGFR/ERK signaling appears to play an important role in fibrosis diseases. In this study, sprague-dawley rats were exposed to different doses of arsenite for 36 weeks to investigate the roles of EGFR/ERK signaling on arsenite-induced liver fibrogenesis. Our results showed that long-term arsenite exposure induced liver fibrosis, accompanied by hepatic stellate cells (HSCs) activation, excessive serum secretion of extracellular matrix (ECM), and hepatocytes epithelial-mesenchymal transformation (EMT). In addition, arsenite exposure caused hyperphosphorylation of EGFR/ERK signaling in liver tissue of rats, indicating that EGFR/ERK signaling may be involved in arsenite-induced liver fibrosis. Indeed, erlotinib (a specific phosphorylation inhibitor of EGFR) intervention significantly decreased arsenite induced hyperphosphorylation of EGFR/ERK signaling, thereby suppressed hepatocytes EMT process and alleviated liver fibrogenesis in arsenite exposed rats. In summary, the present study provides evidences showing that hyperphosphorylation of EGFR/ERK signaling facilitates long-term arsenite-induced hepatocytes EMT and liver fibrosis in rats, which brings new insights into the pathogenesis of arsenic-induced liver injury.

Blimp1 suppressed CD4+ T cells-induced activation of fibroblast-like synoviocytes by upregulating IL-10 via the rho pathway

BACKGROUND

B lymphocyte-induced maturation protein 1 (Blimp1) is a risk allele for rheumatoid arthritis (RA), but its functional mechanism in RA remains to be further explored.

METHODS

Flow cytometry was performed to detect CD4⁺ T cell differentiation. ELISA was used to measure inflammatory factor secretion. Lentivirus mediated Blimp1 overexpression vector (LV-Blimp1) or short hairpin RNA (sh-Blimp1) were used to infect CD4⁺ T cells stimulated by anti-CD28 and anti-CD3 mAbs. RA fibroblast-like synoviocytes (FLSs) were co-cultured with CD4⁺ T cells or T cell conditioned medium (CD4CM), and cell proliferation, invasion, and expression of adhesion molecules and cytokines in FLSs were evaluated. Mice were injected intradermally with type II collagen to establish a collagen-induced arthritis (CIA) mouse model, and the severity of CIA was evaluated with H&E and Safranin-O staining.

RESULTS

Blimp1 knockdown increased pro-inflammatory factor secretion, but downregulated IL-10 concentration in activated CD4⁺ T cells. Blimp1 overexpression promoted regulatory T cells (Treg) CD4⁺ T cell differentiation and hindered T helper 1 (Th1) and T helper 17 (Th17) CD4⁺ T cell differentiation. Blimp1 overexpression suppressed the expression of pro-inflammatory factors and adhesion molecules in CD4⁺ T cells by upregulating IL-10. Moreover, Blimp1 overexpression impeded the enhanced effect of CD4⁺ T cells/CD4CM on cell adhesion, inflammation, proliferation, invasion and RhoA and Rac1 activities in FLSs by upregulating IL-10. Additionally, administration with LV-Blimp1 alleviated the severity of CIA.

CONCLUSION

Blimp1 restrained CD4⁺ T cells-induced activation of FLSs by promoting the secretion of IL-10 in CD4⁺ T cells via the Rho signaling pathway.

Genome-wide DNA methylation pattern in whole blood of patients with coal-burning arsenic poisoning

Exposure to coal-burning arsenic leads to an increased risk of cancer, multi-systems damage and chronic diseases, with DNA methylation one potential mechanism of arsenic toxicity. There are few studies on genome-wide methylation in the coal-burning arsenic poisoning population. Illumina 850 K methylation beadchip is the most suitable technology for DNA methylation of epigenome-wide association analysis. This study used 850 K to detect changes in Genome-wide DNA methylation in whole blood samples of 12 patients with coal-burning arsenic poisoning ( Arsenic poisoning group) and four healthy control participants (Healthy control group). There is clearly abnormal genome-wide DNA methylation in coal-burning arsenic poisoning, with 647 significantly different methylation positions, 524 different methylation regions and 335 significantly different methylation genes in arsenic poisoning patients compared with healthy controls. Further functional analysis of Gene ontology (GO) and Kyoto encyclopedia of genes (KEGG) found 592 GO items and 131 KEGG pathways between patients of coal-burning arsenic poisoning and healthy control. Then, analysis of gene degree and combined-score identified NAPRT1, NT5C3B, NEDD4L, SLC22A3 and RAB11B as target genes. Further validation by qRT-PCR indicates that mRNA expression of five genes changes significantly in the arsenic poisoning group (n = 72) compared to the healthy control group (n = 72). These results showed the genome-wide methylation pattern and highlighted five critical genes within the coal-burning arsenic poisoning population that involve Nicotinate and nicotinamide metabolism, Choline metabolism in cancer, and Ubiquitin mediated proteolysis. Next, the methylation profile of coal burning arsenic poisoning will be further excavation and the mechanism of coal burning arsenic poisoning will be further explored from five genes related pathways and functions.

PINK1/Parkin-Mediated Mitophagy Partially Protects against Inorganic Arsenic-Induced Hepatic Macrophage Polarization in Acute Arsenic-Exposed Mice

Inorganic arsenic is a well-known environmental toxicant and carcinogen, and there is overwhelming evidence for an association between this metalloid poisoning and hepatic diseases. However, the biological mechanism involved is not well characterized. In the present study, we probed how inorganic arsenic modulates the hepatic polarization of macrophages, as well as roles of PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy participates in regulating the metalloid-mediated macrophage polarization. Our results indicate that acute arsenic exposure induced macrophage polarization with up-regulated gene expression of inducible nitric oxide synthase (Inos) and arginase-1 (Arg1), monocyte chemotactic protein-1 (Mcp-1) and macrophage inflammatory protein-2 (Mip-2), tumor necrosis factor (Tnf)-α, interleukin (Il)-1β and Il-6, as well as anti-inflammatory factors Il-4 and Il-10. In parallel, we demonstrated the disrupted hepatic redox balance typically characterized by the up-regulation of hydrogen peroxide (H₂O₂) and glutathione (GSH), and activation of PINK1/Parkin-mediated mitophagy in the livers of acute arsenic-exposed mice. In addition, our results demonstrate that it might be the PINK1/Parkin-mediated mitophagy that renders hepatic macrophage refractory to arsenic-induced up-regulation of the genes Inos, Mcp-1, Mip-2, Tnf-α, Il-1β, Il-6 and Il-4. In this regard, this is the first time the protective effects of PINK1/Parkin-mediated mitophagy in inorganic arsenic-induced hepatic macrophage polarization in vivo have been reported. These findings add novel insights into the arsenical immunotoxicity and provide a basis for the preve.ntive and therapeutic potential of PINK1/Parkin-mediated mitophagy in arsenic poisoning.

Association and risk of circulating inflammatory markers with hyperglycemia in coal-burning arsenicosis

BACKGROUND

Several lines of evidence support a significant relationship between exposure to arsenic and diabetes. However, the underlying pathophysiological mechanisms remain incompletely elucidated.

OBJECTIVE

This study examined the association and risk of circulating inflammatory mediators with hyperglycemia in coal-induced arsenicosis.

METHODS

A cross-sectional study was conducted in the typical coal-burning area in which arsenicosis is endemic in Xingren County, Guizhou, China. A total of 299 arsenicosis subjects and 137 non-arsenic exposed volunteers were recruited for the present study. Participant's hyperglycemia-related parameters, including fasting blood glucose (FBG), fasting serum insulin (FINS), homeostasis model assessment for both insulin resistance (HOMA-IR) and pancreatic β-cell function (HOMA-β), as well as circulating inflammatory biomarkers i.e., Interleukins-1β (IL-1β), IL- 2, IL - 6, IL-10, IL- 17, IL-18 and TNF-α), were determined and analyzed after completing questionnaire investigation and physical examination.

RESULTS

The results clearly showed that coal-burning arsenic exposure was significantly associated with hyperglycemia-related outcomes. Specifically, arsenicosis subjects from the coal-burning endemic area showed a higher level of FBG (median 5.87 mmol/L vs. 4.65 mmol/L) and increased prevalence of hyperglycemia (26.76% vs.16.79%) than reference subjects from the non-arsenic endemic area. Increased HOMA-IR (median 1.93 vs.1.44) and declined HOMA-β (median 96.23 vs. 84.91) were also noted in arsenicosis subjects. Moreover, arsenic exposure was significantly associated with the increased risk of hyperglycemia (adjusted OR = 2.32, 95% CI: 1.37,3.93). In addition, a positive association between arsenic exposure and inflammatory response was observed, and the alteration in circulating inflammatory markers were found to be significantly associated with hyperglycemia-related parameters. Meanwhile, there was a positive relationship between elevated circulating IL-1β, IL-18, IL-6, as well as decreased IL-10 and the increasing risk of arsenic-induced hyperglycemia [adjusted OR = 2.19 (95% CI: 1.26, 3.13);1.13 (95%CI: 1.08, 1.37); 1.19 (95% CI: 1.13, 1.56); 1.15(95% CI: 1.05, 1.36); respectively]. Path analysis further revealed that the mediating effect of IL-1β and IL-18 on the relationship between arsenic exposure and hyperglycemia was closely associated with pancreatic β-cell dysfunction, while those of IL-6 and IL-10 on the association between arsenic exposure and hyperglycemia were partially through insulin resistance.

CONCLUSIONS

This population-based study indicated that arsenic exposure has a clear disruptive effect on glucose homeostasis, and an elevated inflammatory response was implicated in the risk of arsenic-induced hyperglycemia.

Recent advancements in toxicology, modern technology for detection, and remedial measures for arsenic exposure: review

Arsenic toxicity has become a major global health concern for humans and animals due to extensive environmental and occupational exposure to arsenic-contaminated water, air, soil, and plant and animal origin food. It has a wide range of detrimental effects on animals, humans, and the environment. As a result, various experimental and clinical studies were undertaken and are undergoing to understand its source of exposures, pathogenesis, identify key biomarkers, the medical and economic impact on affected populations and ecosystems, and their timely detection and control measures. Despite these extensive studies, no conclusive information for the prevention and control of arsenic toxicity is available, owing to complex epidemiology and pathogenesis, including an imprecise approach and repetitive work. As a result, there is a need for literature that focuses on recent studies on the epidemiology, pathogenesis, detection, and ameliorative measures of arsenic toxicity to assist researchers and policymakers in the practical future planning of research and community control programs. According to the preceding viewpoint, this review article provides an extensive analysis of the recent progress on arsenic exposure to humans through the environment, livestock, and fish, arsenic toxicopathology, nano-biotechnology-based detection, and current remedial measures for the benefit of researchers, academicians, and policymakers in controlling arsenic eco-toxicology and directing future research. Arsenic epidemiology should therefore place the greatest emphasis on the prevalence of different direct and indirect sources in the afflicted areas, followed by control strategies.

Meta-analysis of TLR4 pathway-related protein alterations induced by arsenic exposure

Arsenic is a toxic metal, which ultimately leads to cell apoptosis. TLR4 signaling pathway played a key role in immunomodulatory. Therefore, alterations in related proteins on the TLR4 signaling pathway induced by arsenic exposure was systematically reviewed and analyzed by meta-analysis. Some databases were searched including PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and WANFANG MED ONLINE. The results of NF-κB, IKK, NF-κBp65, phospho-NF-κBp65, and TLR4 expressions were analyzed by Review Manage 5.3. In the arsenic intervention group, NF-κB, phospho-NF-κBp65, and TLR4 expression levels were higher than the control group, respectively. SMD and 95%CI were 11.29 (6.34, 16.24), 4.71(1.73, 7.68), and 5.79 (-4.22, 15.80). Compared to controls, in the exposed group, IKK levels were found to be 38.11-fold higher (Z = 0.97; P = 0.33); NF-κBp65 levels were found to be 0.92-fold higher (Z = 3.33; P = 0.0009) for normal cells and tissue, while IKK levels were found to be 5.18-fold lower (Z = 5.34; P < 0.0001); NF-κBp65 levels were found to be 2.01-fold lower (Z = 3.87; P = 0.0001) for abnormal cells. With comparing of low dose, high dose of arsenic exposure was found to reduce the expression of NF-κB, but increase the expression of NF-κBp65. This review supports the alterations in related proteins on the TLR4 signaling pathway induced by arsenic exposure, which is helpful to provide theoretical basis for the mechanism of toxicity of arsenic-induced immune system damage.

Immunosuppression participated in complement activation-mediated inflammatory injury caused by 4-octylphenol via TLR7/IκBα/NF-κB pathway in common carp (Cyprinus carpio) gills

4-octylphenol (4-OP), a toxic estrogenic environmental pollutant, can threaten aquatic animal and human health. However, toxic effect of 4-OP on fish has not been reported. To investigate molecular mechanism of gill poisoning caused by 4-OP exposure, a carp 4-OP poisoning model was established, and then blood and gills were collected on day 60. The results demonstrated that gill was a target organ attacked by 4-OP, and exposure to 4-OP caused carp gill inflammatory injury. There were 1605 differentially expressed genes (DEGs, including 898 up-regulated DEGs and 707 down-regulated DEGs). KEGG and GO were used to further analyze obtained 1605 DEGs, indicating that complement activation, immune response, and inflammatory response participated in the mechanism of 4-OP-caused carp gill inflammatory injury. Our data at transcription level further revealed that 4-OP caused complement activation through triggering complement component 3a/complement component 3a receptor (C3a/C3aR) axis and complement component 5a/complement component 5a receptor 1 (C5a/C5aR1) axis, induced immunosuppression through the imbalances of T helper (Th) 1/Th2 cells and regulatory T (Treg)/Th17 cells, as well as caused inflammatory injury via toll like receptor 7/inhibitor kappa B alpha/nuclear factor-kappa B (TLR7/IκBα/NF-κB) pathway. Taken together, immunosuppression participated in complement activation-mediated inflammatory damage in carp gills after 4-OP treatment. The findings of this study will provide pioneering information and theoretical support for the mechanism of 4-OP poisoning, and will provide reference for the assessment of estrogenic environmental pollution risk.

Role of N6-methyladenosine RNA modification in the imbalanced inflammatory homeostasis of arsenic-induced skin lesions

This study aimed to investigate the effect of N6-methyladenosine (m⁶ A) modification in modulating inflammatory homeostasis of arsenic (As)-induced skin lesions. Our bioinformatic analysis revealed abnormal expression of m⁶ A RNA methylation regulators and cytokines in the arsenic-exposed population. In human keratinocytes, arsenite increased the levels of m⁶ A methylation by upregulating the RNA methyltransferase like 3 (METTL3), mediating the disordered secretion of indicators that reflect inflammatory homeostasis (IL-6, IL-17, and IL-10). The indicators reflecting arsenic-induced skin lesions (Krt1 and Krt10) were also significantly elevated, which contributed to the occurrence of skin lesions. Our results also confirmed the association between METTL3 with inflammatory homeostasis and arsenic-induced skin lesions using arsenic-exposed human skin samples. In the arsenic-exposed group, the upregulation of METTL3 exacerbated the increase in cytokine levels (IL-6, IL-17, and IL-10), which was associated with the upregulation of keratins (Krt1 and Krt10). In addition, significant correlations among these factors corroborate the theoretical links. Finally, alteration of the m⁶ A levels via knockdown or enhancement of the METTL3 protein could antagonize or aggravate arsenite-induced imbalanced inflammatory homeostasis and human keratinocyte damage in HaCaT cells. Collectively, our study reveals some evidence that regulation of m⁶ A modification plays an important role in arsenic-induced skin lesions, which provide a new perspective on the mechanism of arsenite-induced imbalanced inflammatory homeostasis in the field of RNA epigenetics.

Phytochemicals in the Management of Arsenic Toxicity

Arsenic toxicity is a major concern due to its deleterious consequences for human health. Rapid industrialization also has weakened the quality of the environment by introducing pollutants that may disrupt balanced ecosystems, adversely and irreversibly impacting humans, plants, and animals. Arsenic, an important toxicant among all environmental hazards, can lead to several detrimental effects on cells and organs, impacting the overall quality of life. Nevertheless, arsenic also has a rich history as a chemotherapeutic agent used in ancient days for the treatment of diseases such as malaria, cancer, plague, and syphilis when other chemotherapeutic agents were yet to be discovered. Arsenicosis-mediated disorders remain a serious problem due to the lack of effective therapeutic options. Initially, chelation therapy was used to metabolically eliminate arsenic by forming a complex, but adverse effects limited their pharmacological use. More recently, plant-based products have been found to provide significant relief from the toxic effects of arsenic poisoning. They act by different mechanisms affecting various cellular processes. Phytoconstituents such as curcumin, quercetin, diallyl trisulfide, thymoquinone, and others act via various molecular pathways, primarily by attenuating oxidative damage, membrane damage, DNA damage, and proteinopathies. Nonetheless, most of the phytochemicals reviewed here protect against the adverse effects of metal or metalloid exposure, supporting their consideration as alternatives to chelation therapy. These agents, if used prophylactically and in conjunction with other chemotherapeutic agents, may provide an effective approach for management of arsenic toxicity. In a few instances, such strategies like coadministration of phytochemicals with a known chelating agent have led to more pronounced elimination of arsenic from the body with lesser off-site adverse effects. This is possible because combination treatment ensures the use of a reduced dose of chelating agent with a phytochemical without compromising treatment. Thus, these therapies are more practical than conventional therapeutic agents in ameliorating arsenic-mediated toxicity. This review summarizes the potential of phytochemicals in alleviating arsenic toxicity on the basis of available experimental and clinical evidence.

Metabolic characteristics related to the hazardous effects of environmental arsenic on humans: A metabolomic review

Arsenic (As) is a toxic metalloid exist ubiquitously in environment. Epidemiological studies and laboratory animal studies have verified that As damages multiple organs or tissues in the body and is associated with a variety of diseases. Changes in metabolites usually indicate disturbances in metabolic pathways and specific metabolites are considered as biomarkers of diseases or drugs/toxins or environmental effects. Metabolomics is the quantitative measurement of the dynamic multi-parameter metabolic responses of biological systems due to pathophysiological or genetic changes. Current years, some metabolomic studies on the hazardous effect of environmental As on humans have been reported. In this paper, we first overviewed the metabolomics studies of environmental As exposure in humans since 2011, emphasizing on the data mining process of metabolic characteristics related to the hazardous effects of environmental As on humans. Then, the relationship between metabolic characteristics and the toxic mechanism of environmental As exposure in humans were discussed, and finally, the prospects of metabolomics studies on populations exposed to environmental As were put forward. Our paper may shed light on the study of mechanisms, prevention and individualized treatment of As poisoning.

Potential value and mechanism of Rosa roxburghii tratt juice on pro-inflammatory responses in peripheral blood of patients with arsenic poisoning

Increasing evidence supports the role of arsenic in dysregulated immune and inflammation responses, while, safe and effective treatments have not been fully examined. Rosa roxburghii Tratt (RRT), a traditional Chinese edible fruit with potential immunoregulatory activities, was considered as a dietary supplement to explore its protective effects and possible mechanism in arsenic-induced dysregulated inflammation responses. We enrolled 209 arsenicosis patients and 41 controls to obtain baseline data, including the degree of arsenic poisoning prior to the RRT juice (RRTJ) intervention. Then, based on criteria of inclusion and exclusion and the principle of voluntary participation, 106 arsenicosis patients who volunteered to receive treatment were divided into RRTJ (n = 53) and placebo (n = 53) groups randomly. After three months follow-up, 89 subjects (46 and 43 of the RRTJ and placebo groups, respectively) completed the study and were examined for the effects and possible mechanisms of RRTJ on the Th17 cells-related pro-inflammatory responses in peripheral blood mononuclear cells (PBMCs). The PBMCs had higher levels of Th17 and Th17-related inflammatory cytokines IL-17, IL-6, and RORγt. Furthermore, the gene expressions of STAT3 and SOCS3 in PBMCs increased and decreased, respectively. Conversely, RRTJ decreased the number of Th17 cells, secretion of IL-17, IL-6, RORγt, and relative mRNA levels of STAT3, and increased the transcript levels of SOCS3. This study provides limited evidence that possible immunomodulatory effects of RRTJ on the critical regulators, IL-6 and STAT3, of the Th17 cells in arsenicosis patients, which indicated that IL-6/STAT3 pathway might appear as a potential therapeutic target in arsenicosis.