Hepatic Metallothionein Research Articles

Schistosoma mansoni infection induces hepatic metallothionein and S100 protein expression alongside metabolic dysfunction in hamsters.

Schistosomiasis, a widespread neglected tropical disease, presents a complex and multifaceted clinical-pathological profile. Using hamsters as final hosts, we dissected molecular events following Schistosoma mansoni infection in the liver-the organ most severely affected in schistosomiasis patients. Employing tandem mass tag-based proteomics, we studied alterations in the liver proteins in response to various infection modes and genders. We examined livers from female and male hamsters that were: noninfected (control), infected with either unisexual S. mansoni cercariae (single-sex) or both sexes (bisex). The infection induced up-regulation of proteins associated with immune response, cytoskeletal reorganization, and apoptotic signaling. Notably, S. mansoni egg deposition led to the down-regulation of liver factors linked to energy supply and metabolic processes. Gender-specific responses were observed, with male hamsters showing higher susceptibility, supported by more differentially expressed proteins than found in females. Of note, metallothionein-2 and S100a6 proteins exhibited substantial up-regulation in livers of both genders, suggesting their pivotal roles in the liver's injury response. Immunohistochemistry and real-time-qPCR confirmed strong up-regulation of metallothionein-2 expression in the cytoplasm and nucleus upon the infection. Similar findings were seen for S100a6, which localized around granulomas and portal tracts. We also observed perturbations in metabolic pathways, including down-regulation of enzymes involved in xenobiotic biotransformation, cellular energy metabolism, and lipid modulation. Furthermore, lipidomic analyses through liquid chromatography-tandem mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry imaging identified extensive alterations, notably in cardiolipin and triacylglycerols, suggesting specific roles of lipids during pathogenesis. These findings provide unprecedented insights into the hepatic response to S. mansoni infection, shedding light on the complexity of liver pathology in this disease.

The Anti-Oxidative, Anti-Inflammatory, Anti-Apoptotic, and Anti-Necroptotic Role of Zinc in COVID-19 and Sepsis.

Zinc is a structural component of proteins, functions as a catalytic co-factor in DNA synthesis and transcription of hundreds of enzymes, and has a regulatory role in protein-DNA interactions of zinc-finger proteins. For many years, zinc has been acknowledged for its anti-oxidative and anti-inflammatory functions. Furthermore, zinc is a potent inhibitor of caspases-3, -7, and -8, modulating the caspase-controlled apoptosis and necroptosis. In recent years, the immunomodulatory role of zinc in sepsis and COVID-19 has been investigated. Both sepsis and COVID-19 are related to various regulated cell death (RCD) pathways, including apoptosis and necroptosis. Lack of zinc may have a negative effect on many immune functions, such as oxidative burst, cytokine production, chemotaxis, degranulation, phagocytosis, and RCD. While plasma zinc concentrations decline swiftly during both sepsis and COVID-19, this reduction is primarily attributed to a redistribution process associated with the inflammatory response. In this response, hepatic metallothionein production increases in reaction to cytokine release, which is linked to inflammation, and this protein effectively captures and stores zinc in the liver. Multiple regulatory mechanisms come into play, influencing the uptake of zinc, the binding of zinc to blood albumin and red blood cells, as well as the buffering and modulation of cytosolic zinc levels. Decreased zinc levels are associated with increasing severity of organ dysfunction, prolonged hospital stay and increased mortality in septic and COVID-19 patients. Results of recent studies focusing on these topics are summarized and discussed in this narrative review. Existing evidence currently does not support pharmacological zinc supplementation in patients with sepsis or COVID-19. Complementation and repletion should follow current guidelines for micronutrients in critically ill patients. Further research investigating the pharmacological mechanism of zinc in programmed cell death caused by invasive infections and its therapeutic potential in sepsis and COVID-19 could be worthwhile.

Impacts of dietary zinc oxide nanoparticles on the growth and immunity of Nile tilapia could be ameliorated using Nigella sativa oil

BackgroundZinc nanoparticles are documented to be harmful to fish because their accumulation in fish bring about many irreversible changes in their health. Nigella sativa and its oil have been endorsed in aquaculture to improve fish health. MethodsTwo hundred seventy experimental fish (113 ± 5 g body weight) were divided into 6 groups G1–6; control fish fed a diet without any treatment (G1), 0.3% of NSO (G2), 0.5% of NSO (G3), ZnO NPs (40 mg/kg diet) (G4), 0.3% of NSO and ZnO NPs (40 mg/kg diet) (G5), 0.5% of NSO and ZnO NPs (40 mg/kg diet) (G6), the trial lasted for six weeks. ResultsGrowth performance was enhanced in fish received diets containing NSO, final weight (FW), weight gain (WG), daily weight gain (DWG), and relative growth rate (RGR) were significantly increased with lower food conversion ratios (FCR) compared to the control. The hepatic glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased in response to ZnO NPs stress and only 0.5% NSO supplementation could ameliorate such increment. The immune-related genes [interleukin1-beta (IL-1β), tumor necrosis factor-beta (TNF-β), transforming growth factor-beta 2 (TGF-β2) and C-type lysozyme] as well as growth-related gene [insulin-like growth factor 1 (IGF1)] in liver showed an upregulation in fish fed with NSO diets. Administration of ZnO NPs lowered the resistance of Oreochromis niloticus against bacterial infection with Aeromonas hydrophila and NSO could enhance the immunity in the highest tested concentration (0.5%) (G6). ConclusionsThe obtained results implied that NSO could enhance the oxidative and immune status of O. niloticus which could compensate ZnO NPs stress as well as experimental infection of a virulent strain of A. hydrophila. Our results revealed that NSO might increase fish growth and immunity only at a high dose (0.5%).

ZnO-NPs alleviate aflatoxin B1-induced hepatoxicity in ducklings by promoting hepatic metallothionein expression

Aflatoxin B1 (AFB1) is a mycotoxin widely present in animal feed and human food, posing a serious threat to animal and human health. This study was aim to illustrate the mechanism of the protective role of MT against AFB1-induced hepatotoxicity, as well as to explore the feasibility of enhancing the tolerance of poultry to AFB1 by upregulating the expression of hepatic MT. After being exposed to AFB1 (50 ng/kg) primary duckling hepatocytes, the cell viability, the antioxidant index (SOD and GPx) and the mRNA levels of MT downstream genes (PTGR, p53, TrxR, AR and Bcl-2) significantly (p < 0.05) decreased, while the intracellular formation of (AFBO)-DNA adduct content, apoptosis, and MDA content significantly (p < 0.05) increased. Interestingly, overexpression of MT in primary duckling hepatocytes markedly (p < 0.05) reversed the detrimental impact of AFB1 and increased the expression of MT downstream genes. HepG2 cells were applied to study the mechanism how MT works to relieve the hepatic toxicity of AFB1. The ZnO-NPs (20 μg/mL) + AFB1 (20 μg/mL) group significantly (p < 0.05) increased the cell viability, the expression of NRF2, NQO1 and SOD, and expression of MT and MTF-1, as well as significantly (p < 0.05) decreased LDH, ROS and apoptotic rate, comparing with the AFB1 group. While joint treatment with AFB1 and ZnO-NPs, the hepatic toxicity exerted by AFB1 alone was reversed, along with the translocation of MTF-1 from the cytoplasm to the nucleus and upregulated its expression. Duckling trails were further carried out. A total number of 96 1-day-old healthy Cherry Valley commercial ducklings were randomly allocated according to a 2 by 2 factorial arrangement of treatments with the main factors including oral administration of AFB1 (0 vs. 40 μg/kg) and dietary supplementation of ZnO-NPs (0 vs. 60 mg/kg) for 7 days. It showed that AFB1 exposure caused body weight loss (p < 0.05), impaired liver structure and failure in hepatic function (activity of ALT, AST and concentration of TP and GLU) (p < 0.05), and decreases in antioxidant capacity(activity of SOD, CAT and concentration of GSH) (p < 0.05), along with the decrease in hepatic concentration of Zn, increase in expression of apoptosis-related genes and protein CAS3 and mRNA Bcl-2 expression (p < 0.05), and suppressed mRNA levels of antioxidant-related genes MT, SOD1, NRF2, and NQO1 (p < 0.05). In accordance with the cell test, dietary supplementation with ZnO-NPs mitigated the toxicity exerted by AFB1. In conclusion, ZnO-NPs has the protective effects against AFB1-induced hepatocyte injury by activating the expression of MTF-1 and the ectopic induction of MT expression, providing detailed information on the detoxification ability of MT on AFB1.

Biochemical Parameters of Female Wistar Rats and Their Offspring Exposed to Inorganic Mercury in Drinking Water during the Gestational and Lactational Periods.

The aim of this study was to investigate the effects of inorganic mercury (Hg2+) exposure on biochemical parameters of dams and their offspring exposed to metal in drinking water. Female Wistar rats were exposed to 0, 10, and 50 µg Hg2+/mL (as HgCl2) for 42 days corresponding to gestational (21 days) and lactational (21 days) periods. The offspring were sacrificed on postnatal days 10, 20, 30, and 40. Dams exposed to Hg2+ presented a decrease in water intake in gestation [total: F(2,19) = 15.84; p ≤ 0.0001; daily: F(2,21) = 12.71; p = 0.0002] and lactation [total: F(2,19) = 4.619; p = 0.024; daily: F(2,21) = 5.309; p = 0.0136] without alteration in food intake. Dams exposed to 50 µg Hg2+/mL had an increase in kidney total [F(2,21) = 8.081; p = 0.0025] and relative [F(2,21) = 14.11; p = 0.0001] weight without changes in biochemical markers of nephrotoxicity. Moreover, dams had an increase in hepatic [F(2,10) = 3.847; p = 0.0577] and renal [F(2,11) = 6.267; p = 0.0152] metallothionein content concomitantly with an increase in renal Hg levels after Hg2+ exposure. Regarding offspring, the exposure to Hg2+in utero and breast milk increased the relative liver [F(2,18) = 5.33; p = 0.0152] and kidney [F(2,18) = 3.819; p = 0.0415] weight only on the postnatal day 40. In conclusion, dams were able to handle the Hg2+ avoiding the classic Hg2+ toxic effects as well as protecting the offspring. We suggest that this protection is related to the hepatic and renal metallothionein content increase.

Dietary licorice enhances in vivo cadmium detoxification and modulates gut microbial metabolism in mice.

Mass cadmium (Cd) poisoning is a serious health problem in many parts of the world. We propose that dietary intervention can be a practical solution to this problem. This study aimed to identify effective dietary products from traditional Chinese herbs that can detoxify Cd. Five candidate herbal foods with detoxifying potential were selected and subjected to mouse toxicological tests. The chemical composition and dose-response effects of licorice on mouse hepatocytes were determined. Licorice was selected for further tests to examine its effects on growth, tissue Cd accumulation, and gut and liver fitness of mice. The expression of hepatic metallothionein (Mt) genes was quantified in vitro in hepatocytes and in vivo in liver tissues of mice. The results showed that licorice dietary intervention was effective in reducing blood Cd by >50% within 1 month. Cd was also substantially reduced in the heart and lung tissues, but increased 2.1-fold in the liver. The liver of Cd poisoned mice improved with licorice intervention. Licorice treatment significantly induced Cd accumulation and expression of the Mt1 gene in hepatic cells both in vitro and in vivo. Licorice intake substantially altered gut microbial structure and enriched Parabacteroides distasonis. Omics results showed that licorice improved gut metabolism, particularly the metabolic pathways for glycyrrhizin, bile acids, and amino acids. Dietary licorice effectively reduced mouse blood Cd and had a profound impact on liver and gut fitness. We conclude that herbal licorice can be used as a dietary intervention for mass Cd poisoning.

Gestational Cd Exposure in the CD-1 Mouse Sex-Specifically Disrupts Essential Metal Ion Homeostasis.

In CD-1 mice, gestational-only exposure to cadmium (Cd) causes female-specific hepatic insulin resistance, metabolic disruption, and obesity. To evaluate whether sex differences in uptake and changes in essential metal concentrations contribute to metabolic outcomes, placental and liver Cd and essential metal concentrations were quantified in male and female offspring perinatally exposed to 500 ppb CdCl2. Exposure resulted in increased maternal liver Cd+2 concentrations (364 µg/kg) similar to concentrations found in non-occupationally exposed human liver. At gestational day (GD) 18, placental Cd and manganese concentrations were significantly increased in exposed males and females, and zinc was significantly decreased in females. Placental efficiency was significantly decreased in GD18-exposed males. Increases in hepatic Cd concentrations and a transient prenatal increase in zinc were observed in exposed female liver. Fetal and adult liver iron concentrations were decreased in both sexes, and decreases in hepatic zinc, iron, and manganese were observed in exposed females. Analysis of GD18 placental and liver metallothionein mRNA expression revealed significant Cd-induced upregulation of placental metallothionein in both sexes, and a significant decrease in fetal hepatic metallothionein in exposed females. In placenta, expression of metal ion transporters responsible for metal ion uptake was increased in exposed females. In liver of exposed adult female offspring, expression of the divalent cation importer (Slc39a14/Zip14) decreased, whereas expression of the primary exporter (Slc30a10/ZnT10) increased. These findings demonstrate that Cd can preferentially cross the female placenta, accumulate in the liver, and cause lifelong dysregulation of metal ion concentrations associated with metabolic disruption.

Effects of Zinc Glycinate on Growth Performance, Serum Biochemical Indexes, and Intestinal Morphology of Yellow Feather Broilers

The purpose of this study was to investigate the effects of zinc glycinate (Gly-Zn) on growth performance, serum biochemical index, intestinal morphology, and hepatic metallothionein (MT) mRNA expression in the liver of yellow feather broilers. A total of 540 18-day-old yellow feather broilers were randomly divided into three groups: control group (basal diet), ZnSO4 group (basal diet plus 60 mg Zn/kg from ZnSO4), and Gly-Zn group (basal diet plus 60 mg Zn/kg from zinc glycinate). Each treatment group had 6 replicates with 30 birds in each replicate. The experiment lasted for 42 days (18 to 59 days of age). The results showed that Gly-Zn supplementation significantly improved the average daily gain (ADG) and average daily feed intake (ADFI) of broilers during 18 to 39 days of age compared with that in the control group (P < 0.05) but not different from the ZnSO4 group. The Gly-Zn group had higher glutathione peroxidase (GSH-Px) (P < 0.05) and lower malondialdehyde (MDA) concentrations than the broilers in the control and ZnSO4 group. It was also observed that zinc content in the tibia of Gly-Zn group broilers was higher than the control and ZnSO4 group (P < 0.05). The results of intestinal morphology parameters showed that the Gly-Zn group significantly increased the villus height in duodenum and jejunum (P < 0.05) and decreased crypt depth in duodenum and ileum compared to the control group. However, there were no significant differences between the Gly-Zn group and ZnSO4 group in duodenum and ileum regarding intestinal morphology parameters. The Gly-Zn group significantly increased mRNA expression of MT in the liver than both control and ZnSO4 groups (P < 0.05). Collectively, the results indicated that supplementing 60 mg Zn/kg through zinc glycinate improved growth performance and serum indexes as well as intestinal morphology of yellow feather broilers. It also regulates MT gene expression more effectively than the ZnSO4 group at the transcriptional level.

ZnT8 Deficiency Protects From APAP-Induced Acute Liver Injury by Reducing Oxidative Stress Through Upregulating Hepatic Zinc and Metallothioneins.

Zinc transporter 8 (ZnT8) is an important zinc transporter highly expressed in pancreatic islets. Deficiency of ZnT8 leads to a marked decrease in islet zinc, which is thought to prevent liver diseases associated with oxidative stress. Herein, we aimed to investigate whether loss of islet zinc affects the antioxidant capacity of the liver and acute drug-induced liver injury. To address this question, we treated ZnT8 knockout (KO) or wild-type control mice with 300 mg/ kg acetaminophen (APAP) or phosphate-buffered saline (PBS). Unexpectedly, we found that loss of ZnT8 in mice ameliorated APAP-induced injury and was accompanied by inhibition of c-Jun N-terminal kinase (JNK) activation, reduced hepatocyte death, and decreased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). An increase in hepatic glutathione (GSH) was observed, corresponding to a decrease in malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels. APAP-induced inflammation and glycogen depletion were alleviated. In contrast, no significant changes were observed in cytochrome P450 family 2 subfamily E member 1 (CYP2E1), the main enzyme responsible for drug metabolism. Elevated levels of hepatic zinc and metallothionein (MT) were also observed, which may contribute to the hepatoprotective effect in ZnT8 KO mice. Taken together, these results suggest that ZnT8 deficiency protects the liver from APAP toxicity by attenuating oxidative stress and promoting hepatocyte proliferation. This study provides new insights into the functions of ZnT8 and zinc as key mediators linking pancreatic and hepatic functions.

Antioxidant potential of bulk and nanoparticles of naringenin against cadmium-induced oxidative stress in Nile tilapia, Oreochromis niloticus

Abstract The study assessed the attenuating effect of citrus flavonone, naringenin, and its nanoformulation against cadmium (Cd) toxicity in Nile tilapia (Oreochromis niloticus). Nanoparticles of naringenin (NNn) were synthesized; size 165.1 nm (PDI 0.396) in variable shapes; cluster widespread, spherical accumulated, and tubular bacillary. Parallel, mature male Nile tilapia (n = 120 fish) were used for the exposure study. Group I was negative control. The groups II, III, and IV were exposed to 5 ppm of cadmium chloride monohydrate (CdCl2·H2O) for 21 days. Group III was treated with bulk naringenin (BNn) (3 ppm) and group IV was treated with NNn (3 ppm). Group V was exposed only to NNn (3 ppm). Cd-induced oxidative stress was evident from a significant increase in the hepatic malondialdehyde (MDA) levels and modulation of antioxidant enzymes in the liver and kidney. A significant increase in the hepatic metallothionein and HSP70 levels in the gills was observed. Treatment with both BNn and NNn significantly (p ≤ 0.05) reversed the Cd-induced alterations. However, the protective effect of nano naringenin was more profound on the bioaccumulation of Cd in liver and levels of HSP70 in the gills. These key findings could add to the commercial exploitation of naringenin and its nanosized form as a dietary therapeutic molecule.

Zinc Supplementation Prevented Type 2 Diabetes-Induced Liver Injury Mediated by the Nrf2-MT Antioxidative Pathway.

Zinc is an essential trace element that is often reduced under the type 1 diabetic condition. Previous studies demonstrated that zinc deficiency enhanced type 1 diabetes-induced liver injury and that zinc supplementation significantly helped to prevent this. Due to the differences in pathogenesis between type 1 and type 2 diabetes, it is unknown whether zinc supplementation can induce a beneficial effect on type 2 diabetes-induced liver injury. This possible protective mechanism was investigated in the present study. A high-fat diet, along with a one-time dose of streptozotocin, was applied to metallothionein (MT) knockout mice, nuclear factor-erythroid 2-related factor (Nrf) 2 knockout mice, and age-matched wild-type (WT) control mice, in order to induce type 2 diabetes. This was followed by zinc treatment at 5 mg/kg body weight given every other day for 3 months. Global metabolic disorders of both glucose and lipids were unaffected by zinc supplementation. This induced preventive effects on conditions caused by type 2 diabetes like oxidative stress, apoptosis, the subsequent hepatic inflammatory response, fibrosis, hypertrophy, and hepatic dysfunction. Additionally, we also observed that type 2 diabetes reduced hepatic MT expression, while zinc supplementation induced hepatic MT expression. This is a crucial antioxidant. A mechanistic study showed that MT deficiency blocked zinc supplementation-induced hepatic protection under the condition of type 2 diabetes. This suggested that endogenous MT is involved in the hepatic protection of zinc supplementation in type 2 diabetic mice. Furthermore, zinc supplementation-induced hepatic MT increase was unobserved once Nrf2 was deficient, indicating that Nrf2 mediated the upregulation of hepatic MT in response to zinc supplementation. Results of this study indicated that zinc supplementation prevented type 2 diabetes-induced liver injury through the activation of the Nrf2-MT-mediated antioxidative pathway.

Effects of Zinc Lactate Supplementation on Growth Performance, Intestinal Morphology, Serum Parameters, and Hepatic Metallothionein of Chinese Yellow-Feathered Broilers

In poultry, organic zinc compounds have higher bioavailability than inorganic zinc sources. However, as an organic zinc source, the application of zinc lactate (ZL) on Chinese yellow-feathered broilers has been rarely reported. Hence, the present study aimed to investigate the effects of ZL supplementation on growth performance, small intestinal morphology, serum biochemical parameters, immune organ index, as well as hepatic metallothionein of Chinese yellow-feathered broilers. A total of 2100 broilers (19 days old) were randomly assigned to 5 treatment groups, including the control (fed basal diet), ZL40 (basal diet plus 40 mg/kg ZL), ZL60 (basal diet plus 60 mg/kg ZL), ZL80 (basal diet plus 80 mg/kg ZL), and ZS80 (basal diet plus 80 mg/kg ZS. Each treatment group had 6 replicates with 70 chickens per replicate. Compared to the control group, the ZL40 and the ZS80 groups had a lower feed to gain ratio (P < 0.05), ZL40 group had higher duodenum and ileum villus heights (P < 0.05), and ZS80 and ZL80 groups had a lower ratio of villus height to crypt depth in the jejunum (P < 0.01). In addition, the ZL60 group had a higher concentration of total protein (P < 0.05) and activity of glutathione peroxidase (GSH-Px) (P < 0.01) compared with the ZS80 and the control groups. Interestingly, the ZL40, ZL60, and ZL80 groups all had higher levels of hepatic metallothionein than the other groups (P < 0.01). In conclusion, zinc lactate had a higher bioavailability and could be used as an alternative to zinc sulfate.

Effects of dietary zinc levels on growth performance, digestive enzyme activities, plasma physiological response, hepatic antioxidant responses and metallothionein gene expression in juvenile spotted sea bass ( Lateolabrax maculatus )

The current study was conducted to investigate the effects of dietary zinc on growth performance, body composition, feed utilization, digestive enzyme activities, plasma physiological response, antioxidant responses and metallothionein (MT) gene expression in juvenile spotted sea bass, Lateolabrax maculatus. Six experimental diets (D1-6) were formulated with increasing levels of Zn (0, 20, 40, 80, 160 and 320 mg/kg, respectively) supplied as ZnSO4·H2O. The concentrations of Zn in experimental diets were 36, 55, 74, 110, 175 and 327 mg/kg diet determined by analysis. Each experimental diet was assigned to triplicate groups of 25 L. maculatus for a period of 56 days. The weight gain (WG) and specific growth rate (SGR) in the D4, D5 and D6 groups were significantly increased than that of the control group (p < 0.05), while the feed conversion ratio (FCR) significantly decreased (p < 0.05), respectively. The zinc contents of plasma and vertebra were significantly affected by dietary zinc levels, with the highest zinc content of plasma and vertebra occurring in D6 group (p < 0.05). The levels of plasma alkaline phosphatase (AKP), glucose and catalase (CAT) in the D5 and D6 groups were significantly increased compared with those in the control group (p < 0.05). The content of aspartate aminotransferase (AST) and cortisol (COR) in the D3 and D4 groups was significantly decreased compared with that in the control group (p < 0.05). The intestinal Na+, K+-ATP and CK activities in D3 group were significantly higher than those in the control group (p < 0.05). Compared with the control, the D3 group significantly increased the activities of SOD and T-AOC (p < 0.05), and the D5 group significantly decreased the content of MDA (p < 0.05). The expression of intestinal metallothionein (MT) mRNA in D5 and D6 groups was significantly higher than that of fish in control, D2 and D3 groups (p < 0.05), respectively. Based on the broken-line regression analysis of SGR and AKP, the optimal dietary zinc levels for maximal growth of juvenile L. maculatus were estimated to be 92 and 107 mg/kg diet, respectively.

Metallothioneins alter macrophage phenotype and represent novel therapeutic targets for acetaminophen-induced liver injury.

Acetaminophen (APAP) intoxication is the foremost cause of drug-induced liver failure in developed countries. The only pharmacologic treatment option, N-acetylcysteine (NAC), is not effective for patients who are admitted too late and/or who have excessive liver damage, emphasizing the need for alternative treatment options. APAP intoxication results in hepatocyte death and release of danger signals, which further contribute to liver injury, in part by hepatic monocyte/macrophage infiltration and activation. Metallothionein (MT) 1 and 2 have important danger signaling functions and might represent novel therapeutic targets in APAP overdose. Therefore, we evaluated hepatic MT expression and the effect of anti-MT antibodies on the transcriptional profile of the hepatic macrophage population and liver injury following APAP overdose in mice. Hepatic MT expression was significantly induced in APAP-intoxicated mice and abundantly present in human livers. APAP intoxication in mice resulted in increased serum transaminase levels, extended necrotic regions on liver histology and induced expression of proinflammatory markers, which was significantly less pronounced in mice treated with anti-MT antibodies. Anti-MT antibody therapy attenuated proinflammatory macrophage polarization, as demonstrated by RNA sequencing analyses of isolated liver macrophages and in LPS-stimulated bone marrow-derived macrophages. Importantly, NAC and anti-MT antibodies were equally effective whereas administration of anti-MT antibody in combination with NAC exceeded the efficiency of both monotherapies in APAP-induced liver injury (AILI). We conclude that the neutralization of secreted MTs using a monoclonal antibody is a novel therapeutic strategy as mono- or add-on therapy for AILI. In addition, we provide evidence suggesting that MTs in the extracellular environment are involved in macrophage polarization.

Dietary exposure to methyl mercury chloride induces alterations in hematology, biochemical parameters, and mRNA expression of antioxidant enzymes and metallothionein in Nile tilapia.

Methyl mercury chloride "MMC" (CH3ClHg) is an ubiquitous environmental toxicant that causes a variety of adverse effects. In the present study, we investigated the effects of sub-chronic toxicity of MMC on Nile tilapia (Oreochromis niloticus) through the evaluation of growth performance and hematological, biochemical, and oxidative stress biomarkers. From 150 healthy fish, five equally sized treatment groups were created: a control (CT) group fed with a basal diet and four MMC treatment groups exposed to 0.5, 1, 1.5, and 2 mg of MMC per kg of basal diet for 60 days. MMC exposure significantly reduced the growth performance and survival of O. niloticus and decreased red blood cell count and hemoglobin concentration. Treated fish exhibited normocytic normochromic anemia in addition to leucopenia, lymphopenia, granulocytopenia, and monocytopenia. Moreover, MMC exposure significantly affected liver function, including a reduction in the total protein levels while increasing cholesterol and triglyceride levels. It also markedly increased the production of stress biomarkers such as glucose and cortisol levels. Furthermore, MMC significantly elevated the levels of hepatic enzymes, induced tissue damage, and caused inflammation, as indicated by the upregulation of mRNA expression of hepatic metallothionein. Finally, MMC exposure induced oxidative stress by altering the antioxidant status of the liver and downregulating the mRNA expression of superoxide dismutase, glutathione peroxidase, and glutathione S-reductase. In conclusion, MMC toxicity induced hematological and biochemical alterations, leading to an enhanced state of oxidative stress in O. niloticus.

Screening Dietary Herbs for Health Intervention on Mass Cadmium Poisoning

Objective: Mass cadmium (Cd) poisoning is a serious health problem in many parts of the world. We propose that dietary intervention can be a practical solution to this problem. This study aimed to identify effective dietary products from traditional Chinese herbs that can detoxify Cd. Design: Five candidate herbal foods with detoxifying potential were selected and subjected to mouse toxicological tests. The chemical composition and dose-response effects of licorice on mouse hepatocytes were determined. Licorice was selected for further tests to examine its effects on growth, tissue Cd accumulation, and gut and liver fitness of mice. The expression of hepatic metallothionein (Mt) genes was quantified in vitro in hepatocytes and in vivo in liver tissues of mice. Results: The results showed that licorice dietary intervention was effective in reducing blood Cd by > 50% within 1 month. Cd was also substantially reduced in the heart and lung tissues, but increased 2.1-fold in the liver. The liver of Cd poisoned mice improved with licorice intervention. Licorice treatment significantly induced Cd accumulation and expression of the Mt1 gene in hepatic cells both in vitro and in vivo. Licorice intake substantially altered gut microbial structure and enriched Parabacteroides distasonis. Omics results showed that licorice improved gut metabolism, particularly the metabolic pathways for glycyrrhizin, bile acids, and amino acids. Conclusion: Dietary licorice effectively reduced mouse blood Cd and had a profound impact on liver and gut fitness. We conclude that herbal licorice can be used as a dietary intervention for mass Cd poisoning. Funding: This work was supported by the Hebei Provincial Science Fund or Distinguished Young Scholars (No. D2018503005), the National Key Research and Development Program of China (No.2018YFD0800306), and the National Natural Science Foundation of China (Nos. 41877414 and 31700228). Declaration of Interest: None to declare. Ethical Approval: The study was approved by the Animal Care and Use Committee of the Hebei Science and Technical Bureau, China

Differential regulation of endoplasmic reticulum stress-induced autophagy and apoptosis in two strains of gibel carp (Carassius gibelio) exposed to acute waterborne cadmium

Previous studies illustrated that gibel carp F strain displays better lipid mobilization and antioxidant ability and compared to the A strain. We therefore hypothesized that the F strain would exhibit superior defense to cadmium exposure. Comparative studies were conducted between A and F strains using plasma stress biomarkers, histological observations, and analysis of hepatic molecular events to examine exposure to waterborne Cd (11.9 mg L−1) for 48 h and 96 h. Waterborne Cd exposure stimulated stress response and hepatic metallothionein mRNA induction in both gibel carp strains confirming exposure. Antioxidant responses were stimulated to counteract Cd toxicity, suggested by the upregulation of mRNA levels of genes associated with nuclear factor erythroid 2-related factor 2 (nrf2) signaling. Cd exposure induced endoplasmic reticulum (ER) stress, meanwhile, branches of genes in unfolded protein response (UPR) were activated. Slight time-dependent effects were implied by greater ER stress, UPR, and apoptosis signals with the duration of Cd exposure. Genotype-specific effects were identified, revealing that the F strain showed greater stress at 96 h exposure and higher antioxidant response compared to the A strain, as indicated by the mRNA levels of genes in nrf2 signaling. ER stress and UPR were also stronger in the F strain after Cd exposure. In contrast, the A strain showed higher autophagy and apoptosis response compared to the F strain. Collectively, combined autophagy and apoptosis were triggered under ER stress, which might serve as defense strategies in both gibel carp strains. The F strain showed greater antioxidant detoxification response and UPR to mitigate Cd toxicity, whereas excessive ER stress contributed to higher autophagy and apoptosis in the A strain. The present study uncovered the differential regulation and defense strategies in fish strains exposed to metal exposure.

Synthetic fish metallothionein design as a potential tool for monitoring toxic metals in water.

The diversity of aquatic ecosystems impacted by toxic metals is widely distributed throughout the world. The application of metallothionein (MT) as an early warning sign of metal exposure in freshwater fish is important in biomonitoring, but a more accessible, sensitive, safe, and efficient new methodological strategy is necessary. On this way, a fish MT synthetic gene from Oreochromis aureos was expressed in Escherichia coli to produce polyclonal antibodies against the protein. In the validation assays, these antibodies were able to detect hepatic MT from freshwater fishes Oreochromis niloticus, Pimelodus maculatus, Prochilodus lineatus, and Salminus brasiliensis showing a potential tool for toxic metals biomarker in biomonitoring of aquatic ecosystems. The current results showed the applicability of this molecule in quantitative immunoassays as a sensor for monitoring aquatic environments impacted by toxic metals. Due to the lack of methods focusing on metal pollution diagnostics in aquatic ecosystems, the current proposal revealed a promising tool to applications in biomonitoring programs of water resources, mainly in Brazil where the mining activity is very developed.

Mercury toxicity in pregnant and lactating rats: zinc and N-acetylcysteine as alternative of prevention.

This study evaluated the toxic effects of inorganic mercury (Hg) in pregnant and lactating rats, as well as the possible protective effect of zinc (Zn) and N-acetylcysteine (NAC). Pregnant and lactating rats were pre-treated with ZnCl2 (27mg/kg) and/or NAC (5mg/kg) and after 24h, they were exposed to HgCl2 (10mg/kg). Animals were sacrificed 24h after Hg exposure, and biochemical tests and metal determination were performed. Regarding pregnant rats, Hg exposure caused kidney, blood, and placenta δ-aminolevulinic acid dehydratase (δ-ALA-D) activity inhibition, and the pre-treatments showed a tendency of protection. Moreover, all the animals exposed to Hg presented high Hg levels in the kidney, liver, and placenta when compared with control group. Pregnant rats pre-exposed to Zn (Zn-Hg and Zn/NAC-Hg groups) presented an increase in hepatic metallothionein levels. Therefore, lactating rats exposed to Hg presented renal and blood δ-ALA-D inhibition; the pre-treatments showed a tendency to prevent the renal δ-ALA-D inhibition and prevented the blood δ-ALA-D inhibition caused by Hg. Lactating rats exposed to Hg presented high Hg levels in the kidney and liver. These results showed that 10mg/kg of HgCl2 causes biochemistry alterations in pregnant and lactating rats, and Zn and NAC present promising results against these damages.

Type I Interferons Ameliorate Zinc Intoxication of Candida glabrata by Macrophages and Promote Fungal Immune Evasion.

SummaryHost and fungal pathogens compete for metal ion acquisition during infectious processes, but molecular mechanisms remain largely unknown. Here, we show that type I interferons (IFNs-I) dysregulate zinc homeostasis in macrophages, which employ metallothionein-mediated zinc intoxication of pathogens as fungicidal response. However, Candida glabrata can escape immune surveillance by sequestering zinc into vacuoles. Interestingly, zinc-loading is inhibited by IFNs-I, because a Janus kinase 1 (JAK1)-dependent suppression of zinc homeostasis affects zinc distribution in macrophages as well as generation of reactive oxygen species (ROS). In addition, systemic fungal infections elicit IFN-I responses that suppress splenic zinc homeostasis, thereby altering macrophage zinc pools that otherwise exert fungicidal actions. Thus, IFN-I signaling inadvertently increases fungal fitness both in vitro and in vivo during fungal infections. Our data reveal an as yet unrecognized role for zinc intoxication in antifungal immunity and suggest that interfering with host zinc homeostasis may offer therapeutic options to treat invasive fungal infections.