Lead and copper led to the dysregulation of bile acid homeostasis by impairing intestinal absorption in Bufo gargarizans larvae: An integrated metabolomics and transcriptomics approach

The repairing effect of baicalein on lead induced damage to the gut-liver axis in tadpoles

Baicalein has pharmacological functions, such as antioxidant and anti-inflammatory properties, and has been shown to alleviate damage to organs caused by environmental pollutants. However, the mechanism by which baicalein reduces the toxic effects of metals needs further research. This study used Pelophylax nigromaculatus tadpoles as a model to explore the toxicological effects of lead (Pb) on the gut-liver axis, and the mechanism by which baicalein alleviates lead toxicity. Analysis of the gut microbiota showed that baicalein alleviated abnormal changes in the gut microbiota following Pb exposure, mainly by increasing the abundance of beneficial bacterial genera, including Cetobacterium, Clostridioides, and Monoglobus. Liver metabolomics showed that compared to a natural recovery, baicalein treatment significantly increased the content of metabolites such as uridine, 17α-hydroxypregnenolone, niacin, and cucurbitacin E, and significantly reduced the content of metabolites such as linoleic, gluconic acid, and tetrahydrocortisone. These differential metabolites could be enriched in pathways such as pyrimidine metabolism, nicotinic acid and nicotinamide metabolism, and steroid hormone biosynthesis, which were beneficial for the treatment of liver injury. There was a significant correlation between the gut microbiota and the main differential metabolites in the liver with the addition of baicalein. The improvement of these metabolic pathways by baicalein is beneficial for the repair of the liver and intestines. Therefore, baicalein can increase the abundance of beneficial gut microbiota, improve liver metabolism, and thus reduce the damage of Pb exposure to the gut-liver axis.

UHPLC-QTOF-MS-based metabolomics joint high-throughput RNA sequencing transcriptomics approach for the analysis of fecal and liver biological samples and application in a case study for the mechanism of Qing-Kai-Ling oral liquid in treating MASLD

Qing-Kai-Ling (QKL) oral liquid has been increasingly used in metabolic dysfunction-associated steatotic liver disease (MASLD). However, the specific metabolic differentials and metabolic pathway mechanisms that affect the MASLD regulated by QKL remained unclear. In this study, serum biochemical analyses and hematoxylin-eosin staining of the liver revealed QKL reduced liver injury and enhanced lipid metabolism ability, respectively. To clarify the therapeutic mechanism of the QKL in the treatment of MASLD, UHPLC-QTOF-MS non-target metabolomics and RNA-Seq high-throughput sequencing analysis were used to explore the mechanism of the QKL in the treatment of MASLD from the perspective of metabolic-gene interactions. UHPLC-QTOF-MS-based untargeted metabolomics further revealed that there were 196 common differentially expressed metabolites identified among 3 groups; QKL significantly up-regulated 44 metabolites, while 11 metabolites (including N-phenylacetylglutamic acid and glycocholic acid) were downregulated significantly. Moreover, the main metabolic pathways regulated by QKL included amino acids, peptides, bile acids, carbohydrates, linoleic acids, etc. Additionally, the result of the RNA sequencing-based transcriptomics showed that a total of 984 differential genes (DEGs) were identified and 9 important DEGs were obtained. The result of the Kyoto Encyclopedia of Genes and Genomes (KEGG) demonstrated that the 984 DEGs were linked to bile acid metabolism, glycerophospholipid metabolism, insulin resistance, AMPK signaling pathway, etc. Overall, this work was the first to show that QKL regulated metabolites and genes to alleviate MASLD by the UHPLC-QTOF-MS-based untargeted metabolomics joint high-throughput RNA sequencing-based transcriptomics analysis, providing the basis and research method for the treatment of metabolic diseases by QKL and other drugs.

Gallstone Physicochemical Properties and Heavy Metal Concentrations Associated with Gallbladder Carcinogenesis in Assam, India

Gallbladder cancer (GBC) is an aggressive malignancy, with gallstone disease (GSD) recognized as the primary risk factor. Although the precise mechanism linking GSD to GBC remains unclear, evidence suggests that gallstone characteristics play a significant role. This study investigates the physicochemical characteristics of gallstones critical for GBC development. We analyzed 40 gallstone samples from 30 GSD and 10 GBC with GSD (GBCGS) patients using advanced spectroscopic and imaging techniques such as fourier transform infrared (FTIR), powder X-ray diffraction (PXRD), nuclear magnetic resonance (NMR), and scanning electron microscopy energy-dispersive X-ray (SEM-EDX)). Subsequently, elemental analysis of 10 gallstones each from GBCGS and GSD was conducted via inductively coupled plasma-mass spectrometry (ICP-MS). Gallstones from the GSD group were identified as cholesterol (70%), mixed (13.3%), pigment (6.7%), and calcium carbonate (10%), while the GBCGS group included only cholesterol (70%) and mixed (30%) types. Cholesterol was the dominant organic component in most gallstones, with the cholesterol and mixed types exhibiting highly crystalline phases characterized by a stacked plate-like microstructure, particularly prominent in the GBCGS group. Additionally, the GBCGS group revealed significantly higher concentrations of carcinogenic elements such as arsenic, chromium, mercury, iron, and lead (p < 0.05), suggesting their accumulation in the gallbladder and gallstones. Consequently, our findings highlight that the physicochemical properties of cholesterol-rich gallstones and exposure to carcinogenic elements play a key role in the pathogenesis of GBC in Assam. These results emphasize the need for further research into cholesterol dysregulation and its link to elemental toxicity.

Lactiplantibacillus plantarum FEED8 Biosynthesis of Pyranoanthocyanin (Cyanidin-3-glucoside-4-vinylcatechol) Improves Oxidative Stress and Inflammation of the Gut Microbiome in Cadmium-Exposed Mice

The study is to explore the biosynthesis of cyanidin-3-glucoside-4-vinylcatechol (C3G_VC) through Lactiplantibacillus plantarum-fermented caffeic acid and cyanidin-3-glucoside (C3G) extract (molar ratio = 1:30) in the model medium. C3G_VC was isolated and purified by a venusil ASB-C18 column with a medium-pressure liquid chromatography (MPLC) system. The chemical structure of C3G_VC was identified by high-performance liquid chromatography (HPLC), which showed the maximum absorption wavelength of 505.57 nm. This study showed that Cd exposure of mice induced liver damage, oxidative stress, and inflammation of the gut microbiome. Our findings demonstrated that C3G_VC intervention in Cd-exposed mice significantly mitigated oxidative stress injury by declining the malondialdehyde (MDA) level and increasing the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in the liver, meanwhile alleviating liver injury by decreasing the bile acid (BA) level and accelerating the excretion of fecal BA. Moreover, the Cd_C3G_VC group showed elevated levels of mRNA expression of pro-inflammatory cytokines (IL6, IL1β, and TNF-α) and inhibited BA synthesis (CYP7A1) in Cd-exposed mice. The fermentation results in vitro showed that C3G_VC had a higher residue than that of cyanidin-3-glucoside. The 16S rRNA high-throughput sequencing disclosed that C3G_VC intervention in Cd-exposed mice significantly increased the abundance of Faecalibaculum and unidentified_Lachnospiraceae. It is noteworthy that the C3G_VC supplement increased the abundance of Akkermansia. Overall, this study demonstrated that C3G_VC intervention in Cd-exposed mice had the potential to decrease the occurrence of inflammatory and oxidative stress and maintain bile acid homeostasis by regulating gut microflora.

Combined transcriptomics and metabolomics to reveal the effects of copper exposure on the liver of rainbow trout(Oncorhynchus mykiss)

Copper (Cu) is recognized as an essential trace elements for the body; However, excessive levels of Cu can lead to toxic effects. We investigated the effects of Cu2+(75 μg/L, 150 μg/L, and 300 μg/L) on the rainbow trout liver. Combination of transcriptome and metabolome analyses, the regulatory mechanisms of the liver under Cu stress were elucidated. The results showed that Cu affected the antioxidant levels, leading to disruptions in the normal tissue structure of the liver. Combined transcriptome and metabolome analyses revealed significant enrichment of the insulin signaling pathway and the adipocytokine signaling pathway. Additionally, Cu2+ stress altered the amino acid metabolism in rainbow trout by reducing serine and arginine levels while increasing proline content. Apoptosis is inhibited and autophagy and lipid metabolism are suppressed; In summary, Cu2+ stress affects energy and lipid metabolism, and the reduction of serine and arginine represents a decrease in the antioxidant capacity, whereas the increase in proline and the promotion of apoptosis potentially serving as crucial strategies for Cu2+ resistance in rainbow trout. These findings provided insights into the regulatory mechanisms of rainbow trout under Cu2+ stress and informed the prevention of heavy metal pollution and the selection of biomarkers under Cu pollution.

Gut dysbiosis of Rana zhenhaiensis tadpoles after lead (Pb) exposure based on integrated analysis of microbiota and gut transcriptome

Lead (Pb) is a ubiquitously detected heavy metal pollutant in aquatic ecosystems. Previous studies focused mainly on the response of gut microbiota to Pb stress, with less emphasis on gene expression in intestine, thereby limiting the information about impacts of Pb on intestinal homeostasis in amphibians. Here, microbial community and transcriptional response of intestines in Rana zhenhaiensis tadpoles to Pb exposure were evaluated. Our results showed that 10 μg/L Pb significantly decreased bacterial diversity compared to the controls by the Simpson index. Additionally, 1000 μg/L Pb exposure resulted in a significant reduction in the abundance of Fusobacteriota phylum and Cetobacterium genus but a significant expansion in Hafnia-Obesumbacterium genus. Moreover, transcriptome analysis revealed that about 90 % of the DEGs (8458 out of 9450 DEGs) were down-regulated in 1000 μg/L Pb group, mainly including genes annotated with biological functions in fatty acid degradation, and oxidative phosphorylation, while up-regulated DEGs involved in metabolism of xenobiotics by cytochrome P450. The expression of Gsto1, Gsta5, Gstt4, and Nadph showed strong correlation with the abundance of genera Serratia, Lactococcus, and Hafnia-Obesumbacterium. The findings of this study provide important insights into understanding the influence of Pb on intestinal homeostasis in amphibians.

Synergistic impacts of antibiotics and heavy metals on Hermetia illucens: Unveiling dynamics in larval gut bacterial communities and microbial metabolites

Hermetia illucens larvae showcases remarkable bioremediation capabilities for both antibiotics and heavy metal contaminants. However, the distinctions in larval intestinal microbiota arising from the single and combined effects of antibiotics and heavy metals remain poorly elucidated. In this study, we delved into the details of larval intestinal bacterial communities and microbial metabolites when exposed to single and combined contaminants of oxytetracycline (OTC) and hexavalent chromium (Cr(VI)). After conversion, single contaminant-spiked substrate showed 75.5% of OTC degradation and 95.2% of Cr(VI) reductiuon, while combined contaminant-spiked substrate exhibited 71.3% of OTC degradation and 93.4% of Cr(VI) reductiuon. Single and combined effects led to differences in intestinal bacterial communities, mainly reflected in the genera of Enterococcus, Pseudogracilibacillus, Gracilibacillus, Wohlfahrtiimonas, Sporosarcina, Lysinibacillus, and Myroide. Moreover, these effects also induced differences across various categories of microbial metabolites, which categorized into amino acid and its metabolites, benzene and substituted derivatives, carbohydrates and its metabolites, heterocyclic compounds, hormones and hormone-related compounds, nucleotide and its metabolites, and organic acid and its derivatives. In particular, the differences induced OTC was greater than that of Cr(VI), and combined effects increased the complexity of microbial metabolism compared to that of single contaminant. Correlation analysis indicated that the bacterial genera, Preudogracilibacillus, Enterococcus, Sporosarcina, Lysinibacillus, Wohlfahrtiimonas, Ignatzschineria, and Fusobacterium exhibited significant correlation with significant differential metabolites, these might be used as indicators for the resistance and bioremediation of OTC and Cr(VI) contaminants. These findings are conducive to further understanding that the metabolism of intestinal microbiota determines the resistance of Hermetia illucens to antibiotics and heavy metals.

Current understanding of essential trace elements in intrahepatic cholestasis of pregnancy

Trace elements are important components in the body and have fundamental roles in maintaining a healthy and balanced pregnancy process. Either deficiency or excess of trace elements, including selenium, iron, zinc, copper, and magnesium can lead to pregnancy complications. As a rare disorder during pregnancy of unknown aetiology, intrahepatic cholestasis of pregnancy (ICP) poses a significant risk to the fetus of perinatal mortality. ICP is a multifactorial complication of which the pathogenesis is still an enigma. Epidemiological studies have demonstrated the association of ICP with some trace elements. Evidence from retrospective studies in humans further revealed the possible contributing roles of trace elements in the pathogenesis of ICP. The published literature on the association of trace elements with ICP was reviewed. Recent advances in molecular biological techniques from animal studies have helped to elucidate the possible mechanisms by how these trace elements function in regulating oxidative reactions, inflammatory reactions and immune balance in the maternal-fetal interface, as well as the influence on hepato-intestinal circulation of bile acid. The scenario regarding the role of trace elements in the pathogenesis of ICP is still developing. The administration or depletion of these trace elements may have promising effects in alleviating the symptoms and improving the pregnancy outcomes of ICP.

TGR5 deficiency in excitatory neurons ameliorates Alzheimer's pathology by regulating APP processing

Bile acids (BAs) metabolism has a significant impact on the pathogenesis of Alzheimer's disease (AD). We found that deoxycholic acid (DCA) increased in brains of AD mice at an early stage. The enhanced production of DCA induces the up-regulation of the bile acid receptor Takeda G protein-coupled receptor (TGR5), which is also specifically increased in neurons of AD mouse brains at an early stage. The accumulation of exogenous DCA impairs cognitive function in wild-type mice, but not in TGR5 knockout mice. This suggests that TGR5 is the primary receptor mediating these effects of DCA. Furthermore, excitatory neuron-specific knockout of TGR5 ameliorates Aβ pathology and cognition impairments in AD mice. The underlying mechanism linking TGR5 and AD pathology relies on the downstream effectors of TGR5 and the APP production, which is succinctly concluded as a "p-STAT3-APH1-γ-secretase" signaling pathway. Our studies identified the critical role of TGR5 in the pathological development of AD.

Copper exposure causes alteration in the intestinal microbiota and metabolites in Takifugu rubripes

Copper is an environmental pollutant, and copper in aquatic environments mainly comes from soil and water. It enters the environment through atmospheric deposition, sewage discharge, and industrial production, and enters aquatic organisms, causing toxicity. Takifugu rubripes (T. rubripes) is a marine fish with high economic value. Due to the toxic effects of heavy metals on aquatic organisms such as fish, it can affect the gut community and metabolites of fish. The gut is an important channel for fish to communicate with the outside world and a necessary pathway for the metabolism of nutrients and toxic substances in the fish body. Studies have shown that due to changes in global water emissions and the high sensitivity of aquatic organisms to the environment, copper may pose greater potential hazards to aquatic organisms. Copper poses a greater risk to aquatic species than other heavy metals and metal/metal like pollutants (such as cadmium, lead, mercury, arsenic, etc.) . In order to elucidate the effects of copper exposure on the gut of T. rubripes. In this study, we exposed T. rubripes to 0, 50, 100, or 500 μg/L of copper for three days, the effects of copper exposure on the gut microbiota structure and metabolites of the T. rubripes were investigated using 16 S rRNA gene and metabolomics techniques. The research results indicate that with the increase copper concentration, the intestinal tissue of T. rubripes undergoes significant damage. 16 S rRNA sequencing results show that copper exposure alters the structure and metabolites of intestinal microbiota. Copper exposure of 100 and 500 μg/L inhibited the colonization of the bacterial gut, disrupted the intestinal barrier, and made the fish susceptible to the pathogens. Liquid chromatography-mass spectrometry analysis showed that copper regulated the production of metabolites such as L-histidine, arachidonic acid, and L-glutamic acid, which are related to energy and immunity. Microbiome-metabolome correlation analysis showed that Subdoligranulum, Family_XIII_AD3011_group, and Clostridium_sensu_stricto_1 were the key bacteria for copper ion intervention, and they might up-regulate the levels of metabolites such as indole-3-acetic acid, 3-indoleacrylic acid, and 5-hydroxyindole in the tryptophan metabolism pathway. In summary, our research has demonstrated that copper exposure can cause pathological changes in the intestinal tissue of the T. rubripes. High concentrations of copper ions can affect the colonization of the T. rubripes microbiota in the intestine, damage the fish's immune system, and alter the structure and metabolites of the intestinal microbiota, this can lead to intestinal metabolic dysfunction. providing a reference for the evaluation of the biological toxicity effects of heavy metal elements in the marine environment. This study provides a reference for evaluating the biological toxicity effects of heavy metal elements in marine environments.

A nationwide investigation on the characteristics and health risk of trace elements in surface water across China

Rapid urbanization accelerates the release of anthropogenic heavy metals from local to wider water systems, posing a serious threat to aquatic ecosystems and public health. The characteristics of trace elements were investigated to evaluate the environmental status of surface water in 40 cities of China. The concentrations of 22 elements in surface water ranged from 7.00 × 10-4 to 4.37 × 105 μg/L. The water quality can be classified as "excellent" except Songhuajiang. The levels of As, Cd, Cr, Pb, and Hg are all within the limits permitted by national drinking water quality standards. An obvious regional distribution characteristic was observed, with concentrations of Zn, Mn, Ni, Cu, Co, U, and Cr higher in surface water collected in the north than in the south, while the trends for Cd, Tl, and As are opposite. Notably, Tl shows significant geographical divergences, with the level of surface water collected from the south nine times higher than that from the north. The regional distribution of the mineral, industrial, or agricultural activity might be responsible for the south-to-north difference of these elements. The hazard index (HI) and total cancer risk (TCR) through oral or dermal contact with water-related heavy metals were further calculated. The average HI was 0.54 in the north and 0.29 in the south for adults, while HI for children was relatively higher. The value was 1.01 and 0.55 in the north and south, respectively. TCR in the north is 2.58 × 10-4 and mainly contributed by Cr (88.1 %), while TCR in the south is 4.48 × 10-5 and mainly contributed by As (98.4 %). The research results can provide essential data for effective water resources management and human health protection in China.

Toxic, genotoxic, mutagenic, and bioaccumulative effects of metal mixture from settleable particulate matter on American bullfrog tadpoles (Lithobates catesbeianus)

Amphibians are more susceptible to environmental stressors than other vertebrates due to their semipermeable skin and physiological adaptations to living in very specific microhabitats. Therefore, the aim of the present study was to investigate the effects of a metal mixture from settleable particulate matter (SePM) released from metallurgical industries on Lithobates catesbeianus tadpoles. Endpoints analyzed included metal bioconcentration, morphological (biometrical indices), hematological parameters (hemoglobin and blood cell count), and erythrocyte DNA damage (genotoxicity and mutagenicity). American bullfrog tadpoles (Gosner's stage 25) were kept under control condition (no contaminant addition) or exposed to a sub-lethal and environmentally relevant concentration (1 g.L-1) of SePM for 96 h. Tadpoles exposed to SePM exhibited elevated whole blood levels of Fe56, AL, Sn, Pb, Zn, Cr, Cu, Ti, Rb, V, Ce, La, Ag, As. SePM-exposed tadpoles showed a significant decrease in condition factor (12%) and increases in hepatosomatic index (25%), hemoglobin concentration (17%), and total leukocytes (82%), thrombocytes (90%), and monocytes (78%) abundance. In addition, exposed tadpoles showed higher MN and ENAs (340 and 140%, respectively) frequencies, and erythrocyte DNA damage with approximately 1.2- to 1.8-fold increases in comet parameters. Taken together, these results suggest that the multimetal mixture found in SePM is potentially genotoxic and mutagenic to L. catesbeianus tadpoles, induces stress associated with hematological changes, and negatively affects growth. Although such contamination occurs at sublethal levels, regulatory standards are needed to control the emission of SePM and protect amphibian populations.

Impairment of bile acid metabolism and altered composition by lead and copper in Bufo gargarizans tadpoles

Lead (Pb) and copper (Cu) are two common heavy metal contaminants in environments, and liver is recognized as one of the main target organs for toxicity of Pb and Cu in animal organisms. Bile acids play a critical role in regulating hepatic metabolic homeostasis by activating farnesoid X receptor (Fxr). However, there were few studies on the interactions between bile acids and liver pathology caused by heavy metals. In this work, the histopathological changes, targeted metabolome and transcriptome responses in the liver of Bufo gargarizans tadpoles to Pb and/or Cu were examined. We found that exposure to Pb and/or Cu altered the hepatic bile acid profile, resulting in increased hydrophobicity and toxicity of the bile acid pool. And the expression of genes involved in bile acid metabolism and their downstream signaling pathways in the liver were significantly altered by Pb and/or Cu exposure. The alteration of bile acid profiles and the expression of genes related to bile acid metabolism might induce oxidative stress and inflammation, ultimately inducing hepatocyte injury observed in the histological sections. To our knowledge, this is the first study to provide histological, biochemical, and molecular evidence for establishing the link between Pb and Cu exposure, disturbances in hepatic bile acid metabolism, and liver injury.