Melatonin alleviates Ochratoxin A-induced liver inflammation involved intestinal microbiota homeostasis and microbiota-independent manner

Effect of Ochratoxin A (OTA) on the Immune System: A Systematic Review

Ochratoxin A (OTA) is a mycotoxin with different adverse health effects. The authors conducted a systematic review to evaluate the effects of OTA on the immune system, with more emphasis on its effects on immune system organs, innate and adaptive immunity and related signaling pathways. Studies have demonstrated that exposure to OTA disrupts the functions of immune system organs, resulting in weight loss, histological lesions and a decrease in antibody-secreting cells. There is evidence that OTA impairs epithelial barrier integrity and macrophage function and induces elevated secretion of pro-inflammatory cytokines. In adaptive immunity, OTA regulates T-cell differentiation, particularly Th1 and Th17 subsets, and adversely impacts humoral immunity, ultimately leading to immune suppression.

The relationship between tryptophan metabolism and gut microbiota: Interaction mechanism and potential effects in infection treatment

Human health is influenced by the gut microbiota, particularly in aspects of host immune homeostasis and intestinal immune response. Tryptophan (Trp) not only acts as a nutrient enhancer but also plays a critical role in the balance between host immune tolerance and gut microbiota maintenance. Both endogenous and bacterial metabolites of Trp, exert significant effects on gut microbial composition, microbial metabolism, the host immunity and the host-microbiome interface. Trp metabolites regulate host immunity by activating aryl hydrocarbon receptor (AhR), thereby contributing to immune homeostasis. Among Trp metabolites, AhR ligands include endogenous metabolites (such as kynurenine), and bacterial metabolites (such as indole and its derivatives). Here, we present a comprehensive analysis of the relationships between Trp metabolism and 14 key microbiota, encompassing fungi (e.g., Candida albicans, Aspergillus), bacteria (e.g., Ruminococcus gnavus, Bacteroides, Prevotella copri, Clostridium difficile, Escherichia coli, lactobacilli, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, Helicobacter. Pylori), and viruses (e.g., SARS-CoV-2, influenza virus). This review clarifies how the gut microbiota regulates Trp metabolism and uncovers the underlying mechanisms of these interactions. And increased mechanistic insight into how the microbiota modulate the host immune system through Trp metabolism may allow for the identification of innovative therapies that are specifically designed to target Trp absorption, Trp metabolites, the gut microbiota, or interactions between Trp and gut microbiota to treat both intestinal and extra-intestinal inflammation as well as microbial infections.

Protective Effects of Propolis Supplementation on Aflatoxin B1-Induced Oxidative Stress, Antioxidant Status, Intestinal Barrier Damage, and Gut Microbiota in Rats

Aflatoxin B1 (AFB1) is common in the diets of humans and animals and often leads to adverse health effects. Propolis, with its strong antioxidant activity, can reduce oxidative stress and modulate gut microbiota composition. However, the underlying mechanism by which propolis alleviates AFB1-induced intestinal barrier damage remains unclear. This study was designed to investigate the protective effects of oral propolis supplementation in AFB1-exposed rats. Thirty-two male Sprague-Dawley rats were divided into four groups: control, AFB1, propolis, and AFB1+propolis. After 4 weeks, serum oxidative stress markers were examined, and gut microbiota was analyzed by 16S rRNA sequencing. Intestinal sections were processed by Hematoxylin & Eosin staining, and the expression level of tight junction proteins was assessed by immunostaining. Propolis supplementation in AFB1-exposed rats tended to decrease oxidative stress, and it also restructured the gut microbiota by preventing a decrease in the relative abundances of Lactobacillus, Roseburia, and Phascolarctobacterium. Propolis restored intestinal permeability impaired by AFB1 by ameliorating intestinal morphological damage and increasing the expression levels of tight junction proteins. Propolis supplementation may contribute to the modulation of gut microbiota by alleviating oxidative stress and improving intestinal barrier damage in AFB1-exposed rats.

Ginsenoside Rg1 alleviates ochratoxin A-induced liver inflammation in ducklings: Involvement of intestinal microbiota modulation and the TLR4/NF-κB pathway inhibition

Ochratoxin A (OTA) is a toxic fungal secondary metabolite that triggers liver inflammation in animals. OTA could disrupt intestinal microbiota balance by promoting Gram-negative bacteria growth and activating the Toll-like receptor 4 (TLR4)/Nuclear factor-kappa B (NF-κB) signaling pathway, thereby inducing liver inflammation. Ginsenoside Rg1 (Rg1) is an active component of ginseng, exhibits anti-inflammatory, antibacterial, and antioxidative properties, particularly against gram-negative bacteria. Rg1 has been shown to maintain intestinal microbiota homeostasis and inhibit the TLR4 signaling pathway to alleviate liver inflammation. Given these established mechanisms, the aim of this study was to explore the preventive effect of Rg1 in countering OTA-induced liver inflammation through modulation of intestinal microbiota and the TLR4/NF-κB signaling pathway. The results revealed that Rg1 reduced OTA residues in the cecum and enhanced intestinal barrier function. Moreover, Rg1 ameliorated the intestinal microbiota composition in OTA-treated ducklings by decreasing the relative abundance of lipopolysaccharide (LPS)-related bacteria. Rg1 also increases the abundance of short-chain fatty acid (SCFA)-producing bacteria. Additionally, Rg1 supplementation with OTA decreased the accumulation of LPS in tissues and inhibited the TLR4/NF-κB signaling pathway. Intriguingly, Rg1 maintained its beneficial effects in OTA-treated ducklings even after antibiotic treatment by inhibiting the TLR4/NF-κB pathway. These findings emphasized the importance of intestinal microbiota homeostasis and TLR4/NF-κB pathway suppression in the anti-inflammatory action of Rg1 during OTA-induced liver inflammation.

Polystyrene Microplastics and Cadmium Drive the Gut-Liver Axis Through the TLR4/MyD88/NF-κB Signaling Pathway to Cause Toxic Effects on Broilers

Nowadays, the risk of oral intake of microplastics (MPs) and cadmium (Cd) by poultry is high. In some industrially polluted areas, the chicken feed samples contain 9.60 × 102 ± 1.09 × 102 MPs per kilogram (mean ± std) in wet weight, and the Cd content in chicken feed has been detected to reach up to 5.61 mg/kg. But scholars still focus more on the toxic effects of MPs and Cd on the liver and intestines of aquatic animals. There are few studies that use poultry as research animals and consider these two organs as an integrated system to investigate the toxicity of MPs and Cd on the gut-liver axis and the mechanisms of inflammation. Therefore, in this research, broilers were used as experimental subjects, and experimental models were established by single or combined exposure of MPs (100 mg/L) and Cd (140 mg/kg) to explore the effects of MPs and Cd on the intestinal mucosae and liver of broilers, as well as the mechanisms behind these toxic effects. In this study, the degree of adverse effects (decreased expression of tight junction proteins, changes in intestinal morphology, abundance and diversity of intestinal flora, liver inflammation) caused by the single exposure group was higher than that of the combined exposure group. The results showed that MPs and Cd induced intestinal damage and liver inflammation in broilers by interfering with the TLR4/MyD88/NF-κB pathway and intestinal flora homeostasis. The toxicity of combined exposure was lower than that of single exposure.

Microbiota contribute to regulation of the gut-testis axis in seasonal spermatogenesis

Seasonal breeding is an important adaptive strategy for animals. Recent studies have highlighted the potential role of the gut microbiota in reproductive health. However, the relationship between the gut microbiota and reproduction in seasonal breeders remains unclear. In this study, we selected a unique single food source animal, the flying squirrel (Trogopterus xanthipes), as a model organism for studying seasonal breeding. By integrating transcriptomic, metabolomic, and microbiome data, we comprehensively investigated the regulation of the gut-metabolism-testis axis in seasonal breeding. Here, we demonstrated a significant spermatogenic phenotype and highly active spermatogenic transcriptional characteristics in the testes of flying squirrels during the breeding season, which were associated with increased polyamine metabolism, primarily involving spermine and γ-amino butyric acid. Moreover, an enrichment of Ruminococcus was observed in the large intestine during the breeding season and may contribute to enhanced methionine biosynthesis in the gut. Similar changes in Ruminococcus abundance were also observed in several other seasonal breeders. These findings innovatively revealed that reshaping the gut microbiota regulates spermatogenesis in seasonal breeders through polyamine metabolism, highlighting the great potential of the gut-testis axis in livestock animal breeding and human health management.

Resveratrol Alleviates Fumonisin B1-Induced Cytotoxicity in Sertoli Cells

Fumonisin B1 is a common food contaminant that has been found to adversely affect the reproductive system, especially Sertoli cells. However, the potential mitigation of FB1-induced cytotoxicity in Sertoli cells has not been fully elaborated. Resveratrol is a natural substance with anti-inflammatory, antioxidant, and anti-tumor properties. Herein, the protective effects of resveratrol against FB1-induced cytotoxicity in Sertoli cells were examined in this work. The mouse Sertoli cell line (TM4) was used as a research model. These results indicated that FB1 (40 μM and 80 μM) significantly reduces cell viability, disrupts the cell barrier, and induces an inflammatory response in TM4 cells. To our surprise, resveratrol (15 μM) showed an ability to reverse adverse effects induced by FB1 (40 μM). Furthermore, resveratrol could alleviate the FB1-induced apoptosis, decrease ROS level, and promote the antioxidant enzymes (CAT and SOD2) expression in FB1-treated TM4 cells. The addition of resveratrol could mitigate FB1-induced promoted phosphorylation of JNK and upregulation of c-jun expression. Interestingly, resveratrol was also able to mitigate the cytotoxicity of FB2 (40 μM), FB3 (40 μM), and an FB1-FB2-FB3 (40 μM-40 μM-40 μM) combination group on TM4 cells. In summary, this research displayed that resveratrol may alleviate fumonisin B1-induced cytotoxicity in Sertoli cells via inhibiting oxidative stress-mediated JNK/c-jun signaling pathway-induced apoptosis. This study provides new insights into the prevention and treatment of FB1-induced testicular toxicity and highlights the potential application value of resveratrol.

Effects of embryo injected with ochratoxin A on growth performance, jejunal morphology and barrier of ducklings

1. This trial investigated the effect on embryo injected with ochratoxin A (OTA) and the growth performance, jejunal morphology and barrier of ducklings to 21 d old.2. Two hundred forty, fertilised eggs were individually weighed and randomly assigned to two groups, a control (CON) and the OTA treatment, according to average egg weight. On d 13 of embryonic development, the treatment group was injected with 8 ng OTA/g egg and the CON group was injected with NaHCO3 solution as a placebo. All newly hatched ducklings were assigned to the CON or OTA group based on the different treatments. Each treatment consisted of six replicates and each included 10 ducklings and the experiment lasted until 21 d of age.3. The results showed that embryos injected with OTA affected the 21 d body weight (BW) and average daily gain (ADG) of ducklings (p < 0.05). OTA exposure increased the relative weights of the liver, pancreas, gizzard, proventriculus and jejunum (p < 0.05); and decreased the relative length of the jejunum of ducklings (p < 0.05). Moreover, jejunal crypt depth increased (p < 0.05) and the villus height-to-crypt depth ratio (Vh/Cd) decreased in the OTA-injected group (p < 0.05). Compared with those in the CON group, the mRNA expression of Zonula Occludens-1; (ZO-1) (p = 0.0582) and Occludin; (p = 0.0687) in the OTA treatment group was downregulated.4. The findings demonstrated that a single low-dose injection of OTA increased body weight and daily gain in ducklings. Moreover, embryo exposure to OTA had negative effects with increased relative weight of organs and the jejunal crypt depth, decreased relative length of the intestine and mRNA expression of tight junctions (ZO-1, Occludin).

Inulin Supplementation Alleviates Ochratoxin A-Induced Kidney Injury through Modulating Intestinal Microbiota

Ochratoxin A (OTA) is a prevalent mycotoxin found in feed that causes significant kidney injury in animals. Further investigation was needed to devise strategies for treating OTA-induced kidney damage through the gut-kidney axis. Evidence indicates the crucial role of intestinal microbiota in kidney damage development. Inulin, a dietary fiber, protects kidneys by modulating intestinal microbiota and promoting short-chain fatty acid (SCFA) production. However, its precise mechanism in OTA-induced kidney damage remained unclear. In this study, chickens were orally administered OTA and inulin for 2 weeks to investigate inulin's effects on OTA-induced kidney damage and underlying mechanisms. The alteration of intestinal microbiota, SCFAs contents, and SCFA receptors was further analyzed. Results demonstrated that inulin supplementation influenced intestinal microbiota, increased SCFAs production, and mitigated OTA-induced kidney damage in chickens. The importance of microbiota in mediating inulin's renal protection was further confirmed by antibiotic and fecal microbiota transplantation experiments. Additionally, inulin exhibited antioxidant and anti-inflammatory properties, alleviating NLRP3 inflammasome activation and pyroptosis. In summary, inulin protected chickens from OTA-induced kidney damage, which might provide a potential strategy to mitigate the harmful effects of mycotoxins through prebiotics and safeguard renal health.

Mucus and Biofilm Penetrating Nanoplatform as an Ultrasound-Induced Free Radical Initiator for Targeted Treatment of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) infection is closely associated with the development of various gastric diseases. The effectiveness of current clinical antibiotic therapy is hampered by the rise of drug-resistant strains and the formation of H. pylori biofilm. This paper reports a sonodynamic nanocomposite PtCu3-PDA@AIPH@Fucoidan (PPAF), which consists of dopamine-modified inorganic sonosensitizers PtCu3, alkyl radicals (R•) generator AIPH and fucoidan, can penetrate the mucus layer, target H. pylori, disrupt biofilms, and exhibit excellent bactericidal ability. In vitro experiments demonstrate that PPAF exhibits excellent acoustic kinetic properties, generating a significant amount of reactive oxygen species and oxygen-independent R• for sterilization under ultrasound stimulation. Simultaneously, the produced N2 can enhance the cavitation effect, aiding PPAF nanoparticles in penetrating the gastric mucus layer and disrupting biofilm integrity. This disruption allows more PPAF nanoparticles to bind to biofilm bacteria, facilitating the eradication of H. pylori. In vivo experiments demonstrate that ultrasound-stimulated PPAF exhibited significant antibacterial efficacy against H. pylori. Moreover, it effectively modulated the expression levels of inflammatory factors and maintained gastrointestinal microbiota stability when compared to the antibiotic treatment group. In summary, PPAF nanoparticles present a potential alternative to antibiotics, offering an effective and healthy option for treating H. pylori infection.

Embryo injected with Ochratoxin A induced jejunum injury in ducklings by activating the TLR4 signaling pathway: Involvement of intestinal microbiota

Ochratoxin A (OTA) is a common mycotoxin that causes intestinal injury in humans and various animal species. OTA may lead to intestinal injury in offspring due to the maternal effect. The aim of this study was to investigate the mechanism of embryo injected with OTA induced jejunum injury in ducklings. The results showed that OTA disrupted the jejunum tight junctions in hatching ducklings, and promoted the secretion of inflammatory cytokines. And this inflammatory response was caused by the activation of the TLR4 signaling pathway. Moreover, embryo injected with OTA could cause damage to the intestinal barrier in 21-day-old ducks, characterized by shortened villi, crypt hyperplasia, disrupted intestinal tight junctions, increased level of LPS in the jejunum, activation of the TLR4 signaling pathway, and increased levels of pro-inflammatory cytokines. Meanwhile, OTA induced oxidative stress in the jejunum. And dysbiosis of gut microbiota was mainly characterized by an increased the relative abundance of Bacteroides, Megamonas, Fournierella, and decreased the relative abundance of Alistipes and Weissella. Interestingly, embryo injected with OTA did not induce these changes in the jejunum of antibiotics-treated 21-day-old ducks. In conclusion, embryo injected with OTA induced jejunum injury in ducklings by activating the TLR4 signaling pathway, which involvement of intestinal microbiota.

Melatonin increased antioxidant capacity to ameliorate growth retardation and intestinal epithelial barrier dysfunction in diquat-challenged piglets

BACKGROUND

Diquat is a common environmental pollutant, which can cause oxidative stress in humans and animals. Diquat exposure causes growth retardation and intestinal damage. Therefore, this study was performed to investigate the effects of melatonin on diquat-challenged piglets.

RESULTS

Dietary supplementation with 2 mg kg-1 melatonin significantly increased the average daily gain and feed conversion rate in piglets. Melatonin increased antioxidant capacity, and improved intestinal epithelial barrier function of duodenum and jejunum in piglets. Moreover, melatonin was found to regulated the expression of immune and antioxidant-related genes. Melatonin also alleviated diquat-induced growth retardation and anorexia in diquat-challenged piglets. It also increased antioxidant capacity, and ameliorated diquat-induced intestinal epithelial barrier injury. Melatonin also regulated the expression of MnSOD and immuner-elated genes in intestinal.

CONCLUSION

Dietary supplementation with 2 mg kg-1 melatonin increased antioxidant capacity to ameliorate diquat-induced oxidative stress, alleviate intestinal epithelial barrier injury, and increase growth performance in weaned piglets. © 2023 Society of Chemical Industry.

Fast, portable, selective, and ratiometric determination of ochratoxin A (OTA) by a fluorescent supramolecular sensor

Ochratoxin A (OTA), a mycotoxin found in various food items, possesses significant health risks due to its carcinogenic and toxic properties. Thus, detecting OTA is crucial to ensure food safety. Among the reported analytical methods, there has yet to be one that achieves fast, selective, and portable detection of OTA. In this study, we explore a novel supramolecular sensor, DOCE@ALB, utilizing human serum albumin as the host and a flavonoid fluorescent indicator as the guest. On the basis of indicator displacement assay, this sensor boasts an ultra-fast response time of just 5 s, high sensitivity with a limit of detection at 0.39 ppb, exceptional selectivity, and a noticeable ratiometric fluorescence response to OTA. This discernible color change and portability of the sensor make it suitable for on-site OTA detection in real food samples, including flour, beer, and wine, simply using a smartphone. In comparison to previously reported methods, our approach has showcased notable advantages in both response time and portability, addressing a critical need for food safety and regulatory compliance.

Resveratrol alleviates fumonisin-induced intestinal cytotoxicity by modulating apoptosis, tight junction, and inflammation in IPEC-J2 porcine intestinal epithelial cells

Fumonisins are common contaminants in the global food and environment, pose a variety of health risks to humans and animals. However, the method of mitigating fumonisin toxicity is still unclear. Resveratrol is a natural compound with antioxidant and anti-inflammatory properties. In this study, the protective effect of resveratrol against fumonisin-induced intestinal toxicity was investigated by the porcine intestinal epithelial cell line (IPEC-J2). The cells were treated with 0-40 μM fumonisin for 24 or 48 h with or without the 24 h resveratrol (15 μM) pretreatment. The data showed that resveratrol could alleviate the fumonisin B1 (FB1)-induced decrease in cell viability and amplify in membrane permeability. At the same time, it could reduce the accumulation of intracellular reactive oxygen species and increase the expression ranges of Nrf2 and downstream genes (SOD1 and NQO-1), thereby counteracting FB1-induced apoptosis. Furthermore, resveratrol was able to reduce the expression levels of inflammatory factors (TNF-α, IL-1β, and IL-6), increase the expression levels of tight junction proteins (Claudin-1, Occludin, and ZO-1), and the integrity of the IPEC-J2 monolayer. Our data also showed that resveratrol could attenuate the toxicity of the co-occurrence of three fumonisins. It is implied that resveratrol represents a promising protective approach for fumonisin, even other mycotoxins in the future. This provided a new strategy for further blocking and controlling the toxicity of fumonisin, subsequently avoiding adverse effects on the human and animal health.

Insight into the mechanism of melatonin in attenuating PCB126-induced liver injury: Resistance to ROS-dependent NETs formation to alleviate inflammation and lipid metabolism dysfunction

3,3',4',4',5-Polychlorinated biphenyls (PCB126) is classified as a persistent organic environmental pollutant that can cause liver damage by producing excessive reactive oxygen species (ROS). ROS also can stimulate neutrophil extracellular traps (NETs) formation, which cause damage to organism if NETs are produced in excess. Melatonin is generally considered to possess strong antioxidant and anti-inflammation prosperities, but it is unclear whether it can alleviate PCB126-induced injury. To explore whether PCB126-induced liver injury is related to the formation of NETs and whether melatonin has a potent protective effect, we established PCB126 exposure/ PCB126 and melatonin co-treatment mouse models by gavage. To further clarify the specific mechanism, we also cultured neutrophils and AML12 cells to replicate in vivo model. Here, we found PCB126 exposure resulted in an elevation in the activities of MDA, LPO, PCO, and 8-OHdG, and a reduction in the activities of CAT, GSH-PX and SOD. We found that PCB126 exposure led to an elevation in the expression levels of chemokines (CCL2, CCL3, CCL4, CXCL12, and CXCL8) and marker factors for NETs formation (MPO, NE, NOX2, PKCα, and PKCζ) in the PCB126 group. IF, SYTOX staining, and SEM results also revealed that PCB126 could stimulate NETs formation. In addition, results of a co-culture system of PBNs and AML12 cells revealed that the expression levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) significantly decreased and the expression levels of metabolism factors (Fas, Acc, and Srebp) slightly decreased for scavenging NETs, indicating NETs formation aggravated PCB126-induced hepatic damages. Noteworthy, treatment with melatonin reversed these results. In summary, our findings revealed that melatonin alleviated hepatic damage aggravated by PCB126-induced ROS-dependent NETs formation through suppressing excessive ROS production. This finding not only enriches toxicological mechanism of PCB126, but more importantly extends biological effects of melatonin and its potential application values.

Unveiling the hub genes associated with ochratoxin A-induced hepatotoxicity in broiler chickens

Ochratoxin A (OTA) widely exists in raw food and feed materials and can induce liver damage and toxicity. However, the mechanisms of OTA-induced hepatotoxicity were largely unknown. Thus, our study aimed to uncover the vital genes relevant to OTA-induced hepatotoxicity in broiler chickens. Gene expression data of chicken embryo primary hepatocytes (CEPHs) in OTA-treated and control groups were obtained from the GEO database. Totally 1407 differentially expressed genes (DEGs) were selected, of which 850 and 557 genes were up- and downregulated in OTA-treated CEPHs. Gene ontology (GO) enrichment revealed that the DEGs were in connection with various biological processes, such as signal transduction, extracellular matrix organization, axon guidance, cell division, cholesterol homeostasis, proteolysis, microtubule cytoskeleton organization, and chromosome segregation. Pathway enrichment showed that the DEGs were related to metabolic pathways, ferroptosis, calcium, FoxO, Wnt, cell cycle, apoptosis, calcium, and cell adhesion molecules signaling pathways. Furthermore, the hub genes, including CDK1, DLGAP5, KIF2C, VCL, ITGB3, and ZYX, were identified as hub genes potentially contributing to OTA-induced hepatotoxicity. Taken together, this study provides valuable insights into the mechanisms underlying OTA-induced hepatotoxicity in broiler chickens.

Melatonin Prevents Alcohol- and Metabolic Dysfunction- Associated Steatotic Liver Disease by Mitigating Gut Dysbiosis, Intestinal Barrier Dysfunction, and Endotoxemia

Melatonin (MT) has often been used to support good sleep quality, especially during the COVID-19 pandemic, as many have suffered from stress-related disrupted sleep patterns. It is less known that MT is an antioxidant, anti-inflammatory compound, and modulator of gut barrier dysfunction, which plays a significant role in many disease states. Furthermore, MT is produced at 400-500 times greater concentrations in intestinal enterochromaffin cells, supporting the role of MT in maintaining the functions of the intestines and gut-organ axes. Given this information, the focus of this article is to review the functions of MT and the molecular mechanisms by which it prevents alcohol-associated liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease (MASLD), including its metabolism and interactions with mitochondria to exert its antioxidant and anti-inflammatory activities in the gut-liver axis. We detail various mechanisms by which MT acts as an antioxidant, anti-inflammatory compound, and modulator of intestinal barrier function to prevent the progression of ALD and MASLD via the gut-liver axis, with a focus on how these conditions are modeled in animal studies. Using the mechanisms of MT prevention and animal studies described, we suggest behavioral modifications and several exogenous sources of MT, including food and supplements. Further clinical research should be performed to develop the field of MT in preventing the progression of liver diseases via the gut-liver axis, so we mention a few considerations regarding MT supplementation in the context of clinical trials in order to advance this field of research.

Polysaccharide from walnut green husk alleviates liver inflammation and gluconeogenesis dysfunction by altering gut microbiota in ochratoxin A-induced mice

Walnut green husk polysaccharides (WGP) are isolated from the walnut green husk with a mean molecular weight of 12.77 kDa. The structural characterization revealed by methylation and NMR analysis indicated that WGP might consist of →4-α-D-Galp-(1→, α-D-Galp (1→, and →2)-α-L-Rhap-(1→. Previous studies have been demonstrated that WGP effectively prevented liver injury and modulated gut microbiota in high fructose-treated mice and high fat diet-treated rats. In this study, we found for the first time that WGP presenting outstanding protective effects on liver inflammation and gluconeogenesis dysfunction induced by ochratoxin A (OTA) in mice. Firstly, WGP decreased oxidative stress, down-regulated the expression of inflammatory factors and inhibited the TLR4/p65/IκBα pathway in the liver. Then, WGP reversed OTA-induced lower phosphoenolpyruvate carboxyl kinase (PEPCK), and glucose 6-phosphatase (G6PC) activities in the liver. Furthermore, WGP increased the diversity of gut microbiota and the abundance of beneficial bacteria, especially Lactobacillus and Akkermansia. Importantly, the results of fecal microbiota transplantation (FMT) experiment further confirmed that gut microbiota involved in the protective effects of WGP on liver damage induced by OTA. Our results indicated that the protective effect of WGP on liver inflammation and gluconeogenesis dysfunction caused by OTA may be due to the regulation of gut microbiota.

Insights into the intestinal toxicity of foodborne mycotoxins through gut microbiota: A comprehensive review

Mycotoxins, which are fungal metabolites, pose a significant global food safety concern by extensively contaminating food and feed, thereby seriously threatening public health and economic development. Many foodborne mycotoxins exhibit potent intestinal toxicity. However, the mechanisms underlying mycotoxin-induced intestinal toxicity are diverse and complex, and effective prevention or treatment methods for this condition have not yet been established in clinical and animal husbandry practices. In recent years, there has been increasing attention to the role of gut microbiota in the occurrence and development of intestinal diseases. Hence, this review aims to provide a comprehensive summary of the intestinal toxicity mechanisms of six common foodborne mycotoxins. It also explores novel toxicity mechanisms through the "key gut microbiota-key metabolites-key targets" axis, utilizing multiomics and precision toxicology studies with a specific focus on gut microbiota. Additionally, we examine the potential beneficial effects of probiotic supplementation on mycotoxin-induced toxicity based on initial gut microbiota-mediated mycotoxicity. This review offers a systematic description of how mycotoxins impact gut microbiota, metabolites, and genes or proteins, providing valuable insights for subsequent toxicity studies of mycotoxins. Furthermore, it lays a theoretical foundation for preventing and treating intestinal toxicity caused by mycotoxins and advancing food safety practices.

Ochratoxin A-The Current Knowledge Concerning Hepatotoxicity, Mode of Action and Possible Prevention

Ochratoxin A (OTA) is considered as the most toxic of the other ochratoxins synthesized by various fungal species belonging to the Aspergillus and Penicillium families. OTA commonly contaminates food and beverages, resulting in animal and human health issues. The toxicity of OTA is known to cause liver damage and is still being researched. However, current findings do not provide clear insights into the toxin mechanism of action. The current studies focusing on the use of potentially protective compounds against the effects of the toxin are insufficient as they are mainly conducted on animals. Further research is required to fill the existing gaps in both fields (namely the exact OTA molecular mechanism and the prevention of its toxicity in the human liver). This review article is a summary of the so far obtained results of studies focusing on the OTA hepatotoxicity, its mode of action, and the known approaches of liver cells protection, which may be the base for expanding other research in near future.

Ochratoxin A induces abnormal tryptophan metabolism in the intestine and liver to activate AMPK signaling pathway

BACKGROUND

Ochratoxin A (OTA) is a mycotoxin widely present in raw food and feed materials and is mainly produced by Aspergillus ochraceus and Penicillium verrucosum. Our previous study showed that OTA principally induces liver inflammation by causing intestinal flora disorder, especially Bacteroides plebeius (B. plebeius) overgrowth. However, whether OTA or B. plebeius alteration leads to abnormal tryptophan-related metabolism in the intestine and liver is largely unknown. This study aimed to elucidate the metabolic changes in the intestine and liver induced by OTA and the tryptophan-related metabolic pathway in the liver.

MATERIALS AND METHODS

A total of 30 healthy 1-day-old male Cherry Valley ducks were randomly divided into 2 groups. The control group was given 0.1 mol/L NaHCO3 solution, and the OTA group was given 235 μg/kg body weight OTA for 14 consecutive days. Tryptophan metabolites were determined by intestinal chyme metabolomics and liver tryptophan-targeted metabolomics. AMPK-related signaling pathway factors were analyzed by Western blotting and mRNA expression.

RESULTS

Metabolomic analysis of the intestinal chyme showed that OTA treatment resulted in a decrease in intestinal nicotinuric acid levels, the downstream product of tryptophan metabolism, which were significantly negatively correlated with B. plebeius abundance. In contrast, OTA induced a significant increase in indole-3-acetamide levels, which were positively correlated with B. plebeius abundance. Simultaneously, OTA decreased the levels of ATP, NAD+ and dipeptidase in the liver. Liver tryptophan metabolomics analysis showed that OTA inhibited the kynurenine metabolic pathway and reduced the levels of kynurenine, anthranilic acid and nicotinic acid. Moreover, OTA increased the phosphorylation of AMPK protein and decreased the phosphorylation of mTOR protein.

CONCLUSION

OTA decreased the level of nicotinuric acid in the intestinal tract, which was negatively correlated with B. plebeius abundance. The abnormal metabolism of tryptophan led to a deficiency of NAD+ and ATP in the liver, which in turn activated the AMPK signaling pathway. Our results provide new insights into the toxic mechanism of OTA, and tryptophan metabolism might be a target for prevention and treatment.

MiR-155-5p Elevated by Ochratoxin A Induces Intestinal Fibrosis and Epithelial-to-Mesenchymal Transition through TGF-β Regulated Signaling Pathway In Vitro and In Vivo

Ochratoxin A (OTA) is a mycotoxin that induces fibrosis and epithelial-to-mesenchymal transitions (EMT) in kidneys and livers. It enters our bodies through food consumption, where it is absorbed in the intestines. However, the impact of OTA on the intestines is yet to be studied. MicroRNA (miRNAs) are small non-coding single-stranded RNAs that block the transcription of specific mRNAs and are, therefore, involved in many biochemical processes. Our findings indicate that OTA can induce EMT and intestinal fibrosis both in vivo and in vitro. This study examines the impact of OTA on intestinal toxicity and the role of miRNAs in this process. Following OTA treatment, miR-155-5p was the most elevated miRNA by next-generation sequencing. Our research showed that OTA increased miR-155-5p levels through transforming growth factor β (TGF-β), leading to the development of intestinal fibrosis and EMT. Additionally, the study identified that the modulation of TGF-β and miR-155-5p by OTA is linked to the inhibition of CCAAT/enhancer-binding protein β (C/EBPβ) and Smad2/3 accumulation in the progression of intestinal fibrosis.

Individual and Combined Cytotoxic Effects of Co-Occurring Fumonisin Family Mycotoxins on Porcine Intestinal Epithelial Cell

Human health is seriously threatened by mycotoxin contamination, yet health risk assessments are typically based on just one mycotoxin, potentially excluding the additive or competitive interactions between co-occurring mycotoxins. In this investigation, we evaluated the individual or combined toxicological effects of three fumonisin-family B mycotoxins: fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3), by using porcine intestinal epithelial cells (IPEC). IPEC cells were exposed to various concentrations (2.5-40 μM) for 48 h, and a cell counting kit (CCK8) was used to determine cell vitality. Firstly, we discovered that they might inhibit cell viability. Additionally, the cytotoxicity of FB1 was significantly greater than that of FB2 and FB3. The results also indicated that the combinations of FB1-FB2, FB2-FB3, and FB1-FB2-FB3 showed synergistically toxicological effects at the ID10-ID50 levels and antagonistic effects at the ID75-ID90 levels. In addition, the FB1-FB3 exposure was also synergistic at the ID10-ID25 level. We also found that myriocin and resveratrol alleviated the cytotoxicity induced by fumonisin in IPEC cells. In all, this study may contribute to the determination of legal limits, the optimization of risk assessment for fumonisins in food and feed, and the development of new methods to alleviate fumonisin toxicity.

Melatonin alleviates lung injury in H1N1-infected mice by mast cell inactivation and cytokine storm suppression

Influenza A virus (IAV) H1N1 infection is a constant threat to human health and it remains so due to the lack of an effective treatment. Since melatonin is a potent antioxidant and anti-inflammatory molecule with anti-viral action, in the present study we used melatonin to protect against H1N1 infection under in vitro and in vivo conditions. The death rate of the H1N1-infected mice was negatively associated with the nose and lung tissue local melatonin levels but not with serum melatonin concentrations. The H1N1-infected AANAT-/- melatonin-deficient mice had a significantly higher death rate than that of the WT mice and melatonin administration significantly reduced the death rate. All evidence confirmed the protective effects of melatonin against H1N1 infection. Further study identified that the mast cells were the primary targets of melatonin action, i.e., melatonin suppresses the mast cell activation caused by H1N1 infection. The molecular mechanisms involved melatonin down-regulation of gene expression for the HIF-1 pathway and inhibition of proinflammatory cytokine release from mast cells; this resulted in a reduction in the migration and activation of the macrophages and neutrophils in the lung tissue. This pathway was mediated by melatonin receptor 2 (MT2) since the MT2 specific antagonist 4P-PDOT significantly blocked the effects of melatonin on mast cell activation. Via targeting mast cells, melatonin suppressed apoptosis of alveolar epithelial cells and the lung injury caused by H1N1 infection. The findings provide a novel mechanism to protect against the H1N1-induced pulmonary injury, which may better facilitate the progress of new strategies to fight H1N1 infection or other IAV viral infections.

Melatonin protects against NMDA-induced retinal ganglion cell injury by regulating the microglia-TNFα-RGC p38 MAPK pathway

Glaucoma, one of the most common ocular neurodegenerative diseases worldwide, is characterized by retinal ganglion cell (RGC) loss. There is a large body of literature that describes the neuroprotective role of melatonin against neurodegenerative diseases by regulating neuroinflammation, although the exact mechanism through which melatonin acts on RGC is still uncertain. This study assessed the protective effects of melatonin using a NMDA-induced RGC injury model, and studied the possible mechanisms involved in this process. Melatonin promoted RGC survival, improved retinal function, and inhibited the apoptosis and necrosis of retinal cells. To understand the mechanism of the neuroprotective effects of melatonin on RGC, microglia and inflammation-related pathways were assessed after melatonin administration and microglia ablation. Melatonin promoted RGC survival by suppressing microglia-derived proinflammatory cytokines, in particular TNFα, which in turn inhibited the activation of p38 MAPK pathway. Inhibiting TNFα or manipulating p38 MAPK pathway protected damaged RGC. Our results suggest that melatonin protects against NMDA-induced RGC injury by inhibiting the microglial TNFα-RGC p38 MAPK pathway. It should be considered a candidate neuroprotective therapy against retinal neurodegenerative diseases.

Total Flavonoids of Rhizoma Drynariae Mitigates Aflatoxin B1-Induced Liver Toxicity in Chickens via Microbiota-Gut-Liver Axis Interaction Mechanisms

Aflatoxin B1 (AFB1) is a common mycotoxin that widely occurs in feed and has severe hepatotoxic effects both in humans and animals. Total flavonoids of Rhizoma Drynaria (TFRD), a traditional Chinese medicinal herb, have multiple biological activities and potential hepatoprotective activity. This study investigated the protective effects and potential mechanisms of TFRD against AFB1-induced liver injury. The results revealed that supplementation with TFRD markedly lessened broiler intestinal permeability by increasing the expression of intestinal tight junction proteins, as well as correcting the changes in gut microbiota and liver damage induced by AFB1. Metabolomics analysis revealed that the alterations in plasma metabolites, especially taurolithocholic acid, were significantly improved by TFRD treatment in AFB1-exposed chickens. In addition, these metabolites were closely associated with [Ruminococcus], ACC, and GPX1, indicating that AFB1 may cause liver injury by inducing bile acid metabolism involving the microbiota–gut–liver axis. We further found that TFRD treatment markedly suppressed oxidative stress and hepatic lipid deposition, increased plasma glutathione (GSH) concentrations, and reversed hepatic ferroptosis gene expression. Collectively, these findings indicate that ferroptosis might contribute to the hepatotoxicity of AFB1-exposed chickens through the microbiota–gut–liver axis interaction mechanisms; furthermore, TFRD was confirmed as an herbal extract that could potentially antagonize mycotoxins detrimental effects.

Mechanism of action and promising clinical application of melatonin from a dermatological perspective

Melatonin is the main neuroendocrine product in the pineal gland. Melatonin can regulate circadian rhythm-related physiological processes. Evidence indicates an important role of melatonin in hair follicles, skin, and gut. There appears to be a close association between melatonin and skin disorders. In this review, we focus on the latest research of the biochemical activities of melatonin (especially in the skin) and its promising clinical applications.

Bacterial lipopolysaccharide with different administration routes affects intestinal mucosal morphological, immunological, and microbial barrier functions in goslings

The current study was conducted to evaluate the effects of different administration routes of bacterial lipopolysaccharide (LPS) on intestinal mucosal morphological, immunological, and microbial barrier functions in goslings. First, we compared intestinal villi morphology of goslings under intraperitoneal or oral LPS treatment through hematoxylin and eosin staining. Then, we determined the signatures of the microbiome in the ileum mucosa of goslings subjected to oral LPS treatment at 0, 2, 4, and 8 mg/kg BW by 16S sequencing, and analyzed the changes in intestinal barrier functions and permeability, levels of LPS in the ileum mucosa, plasma, and liver tissue, and the induced inflammatory response of Toll-like receptor 4 (TLR4). As a result, intraperitoneal LPS injection resulted in a thicker intestinal wall in the ileum within a short time, whereas villus height was less affected; in contrast, oral LPS treatment exerted a stronger influence on villus height but not on intestinal wall thickness. We also found that oral LPS treatment affected the structure of the intestinal microbiome, reflected by changes in the clustering of intestinal microbiota. The average abundance of Muribaculaceae showed an increasing trend with increasing LPS levels, and that of the genus Bacteroides decreased, compared with the control group. In addition, oral LPS treatment with 8 mg/kg BW affected the intestinal epithelial morphology, damage the mucosal immune barrier, downregulated the expression of tight junction proteins, increased circulating D-lactate levels, and stimulated the secretion of various inflammatory mediators and activation of the TLR4/MyD88/NFκB pathway. This study presented the injuries of intestinal mucosal barrier function induced by LPS challenges in goslings and provided a scientific model for searching the novel strategies to attenuate the immunological stress and gut injury caused by LPS.

Thiram-induced hyperglycemia causes tibial dyschondroplasia by triggering aberrant ECM remodeling via the gut-pancreas axis in broiler chickens

Pesticide thiram is widely used in agriculture and has been demonstrated to cause tibial dyschondroplasia (TD) in birds. However, the underlying mechanism remains unclear. This work used multi-omics analysis to evaluate the molecular pathways of TD in broilers that were exposed to low level of thiram. Integrative analysis of transcriptomic, proteomic, and metabolomic revealed thiram activity in enhancing pathological ECM remodeling via attenuating the glycolysis pathway and activating the hexosamine and glucuronic acid pathways. Intriguingly, we found hyperglycemia as a crucial factor for ECM overproduction, which resulted in the development of TD. We further demonstrated that high glucose levels are caused by islet secretion dysfunction in thiram-treated broilers. A combination of factors, including lipid disorder, low-grade inflammation, and gut flora disturbance, might contribute to the dysregulation of insulin secretion. The current work revealed the underlying toxicological mechanisms of thiram-induced tibial dyschondroplasia through blood glucose disorder via the gut-pancreas axis in chickens for the first time, which makes it easier to figure out the health risks of pesticides for worldwide policy decisions.

New Insights into How Melatonin Ameliorates Bisphenol A-Induced Colon Damage: Inhibition of NADPH Oxidase

Bisphenol A (BPA) is an endocrine disruptor, widely employed, and detected in many consumer products and food items. Oral intake poses a great threat to intestinal health. Melatonin (MT) stands out as an endogenous, dietary, and therapeutic molecule with potent antioxidant capacity. To explore the protective effect of MT against BPA-induced colon damage and the role of NADPH oxidase (NOX) in this process, we established mice and colonic epithelial cell (NCM460) models of BPA exposure and treated with MT. In vitro and in vivo results showed that MT ameliorated BPA-induced oxidative stress, DNA damage, and the G2/M cell cycle arrest. MT also downregulated the expression of NOX family-related genes, reversed the inhibition of the base excision repair (BER) pathway, promoted the activation of non-homologous end-joining (NHEJ) pathway, and suppressed the mRNA and protein expression of ATM, Chk1/2, and p53. Diphenyleneiodonium chloride (DPI), a NOX-specific inhibitor, also attenuated the toxic effects of BPA on NCM460 cells. Furthermore, molecular docking revealed that MT could bind to NOX. Conclusively, our finding suggested that MT can ameliorate BPA-induced colonic DNA damage by scavenging NOX-derived ROS, which further attenuates G2/M cell cycle arrest dependent on the ATM-Chk1/2-p53 axis.

Melatonin alleviates lead-induced fatty liver in the common carps (Cyprinus carpio) via gut-liver axis

As a widespread aquatic environmental contaminant, Lead (Pb) can provoke hepatic injury in various animals. Melatonin (MT) plays a crucial role in the regulation of inflammatory response. Accumulating evidence elucidates exogenous toxins can elicit hepatic lipid metabolic disorders by influencing the gut microbiome. Nevertheless, the effects of Pb on gut microbiota and hepatic lipid metabolism of the common carps, and whether MT can prevent and cure Pb-induced toxicity via regulating microbiome remains unknown. Here, metagenomic and transcriptomic analysis were subsequently implemented to identify the Pb exposure-triggered prominent alternation of gut-liver signal. In the present study the severe intestinal injury and fatty liver formation caused by Pb in common carp were preliminarily determined. Metagenomic analysis confirmed that the gut microbiome dominant phyla, family and genus of the common carps were Fusobacteria, Fusobacteriaceae and Cetobacterium. Meanwhile, lipopolysaccharide (LPS) biosynthesis pathway was regarded as one of the main responsible for Pb exposure. Subsequently, LPS was demonstrated as the Pb-triggered microbial-derived signal of the common carps by ELISA analysis, and involves in the hepatic metabolic disorders via deteriorating the intestinal barrier. Additionally, it confirmed that hepatocytes ferroptosis associated with Pb-evoked fatty liver of the common carps, and the aggravation of lysosomal dyshomeostasis as well as inhibition of AMPK phosphorylation were referred to lipid metabolic disorders. The results of the present study demonstrated microbial-derived signal induced by aquatic Pb contaminant cause fatty liver formation in the common carps, and the protective effects of MT on Pb toxicity were performed by receding LPS over-synthesis, restraining microbiota-sourced LPS transport, along with attenuation of hepatocytes ferroptosis.

Crosstalk between Mycotoxins and Intestinal Microbiota and the Alleviation Approach via Microorganisms

Mycotoxins are secondary metabolites produced by fungus. Due to their widespread distribution, difficulty in removal, and complicated subsequent harmful by-products, mycotoxins pose a threat to the health of humans and animals worldwide. Increasing studies in recent years have highlighted the impact of mycotoxins on the gut microbiota. Numerous researchers have sought to illustrate novel toxicological mechanisms of mycotoxins by examining alterations in the gut microbiota caused by mycotoxins. However, few efficient techniques have been found to ameliorate the toxicity of mycotoxins via microbial pathways in terms of animal husbandry, human health management, and the prognosis of mycotoxin poisoning. This review seeks to examine the crosstalk between five typical mycotoxins and gut microbes, summarize the functions of mycotoxins-induced alterations in gut microbes in toxicological processes and investigate the application prospects of microbes in mycotoxins prevention and therapy from a variety of perspectives. The work is intended to provide support for future research on the interaction between mycotoxins and gut microbes, and to advance the technology for preventing and controlling mycotoxins.

Zearalenone Promotes LPS-Induced Oxidative Stress, Endoplasmic Reticulum Stress, and Accelerates Bovine Mammary Epithelial Cell Apoptosis

Both zearalenone (ZEA) and lipopolysaccharide (LPS) can induce oxidative stress, and even apoptosis in bovine mammary epithelial cells (MAC-T), but not much attention has been given to the synergistic effect of ZEA and LPS. In this study, we treated MAC-T cells with different concentrations of LPS (1, 10, 50, and 100 μg/mL) and ZEA (5, 15, and 30 μM) to induce cell damage. Previous results show that MAC-T cell viability decreases with increasing LPS concentration. Meanwhile, 1 µg/mL LPS and ZEA were selected for combined treatment in subsequent studies. It was found that co-treatment with ZEA and LPS increases the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), decreases mitochondrial membrane potential (MMP), and superoxide dismutase (SOD), and reduces glutathione (GSH). ZEA and LPS are found to activate endoplasmic reticulum (ER) stress by increasing the expression of glucose-regulated protein 78 kDa (GRP78), activating transcription factor 6 (ATF6) and C/EBP homologous protein (CHOP). It increases cell apoptosis by suppressing the expression of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2), indicated by up-regulation of Bcl2-associated X protein (Bax) and Cysteinyl aspartate-specific proteinases 3 (caspase-3) expression. The above results suggest that the synergistic effect of ZEA and LPS aggravate cytotoxicity.

Bio-control on the contamination of Ochratoxin A in food: Current research and future prospects

Ochratoxin A (OTA) is a secondary metabolite of several fungi and widely exists in various species of foods. The establishment of effective methods for OTA reduction is a key measure to ensure food processing and human health. This article reviews the current research of OTA reduction by biological approaches, summarizes the characteristics and efficiency of them, and evaluates the transformation pathways and metabolites safety of each degradation technology. The shortcomings of various methods are pointed out and future prospects are also proposed. Biological methods are the most promising approaches for OTA control. The defect of them is the long processing time and the growth of microbial cells may affect the product quality. Therefore, the control of OTA contamination should be conducted according to the food processing and their product types. Besides, it is significant for the exploitation of new strains, enzyme and novel adsorbents.

Melatonin mitigates aflatoxin B1-induced liver injury via modulation of gut microbiota/intestinal FXR/liver TLR4 signaling axis in mice

Aflatoxin B1 (AFB1) is a widespread contaminant in foods and feedstuffs, and its target organ is the liver. Melatonin (MT) has been shown to alleviate inflammation in organs and remodel gut microbiota in animals and humans. However, the underlying mechanism by which MT alleviates AFB1-induced liver injury remains unclear. In the present study, MT pretreatment markedly increased the expression of intestinal tight junction proteins (ZO-1, Occludin, and Claudin-1), decreased intestinal permeability, reduced production of gut-derived Lipopolysaccharide (LPS) and remodeled gut microbiota, ultimately alleviated AFB1-induced liver injury in mice. Interestingly, MT pretreatment failed to exert beneficial effects on the intestine and liver in antibiotic-treated mice. Meanwhile, MT pretreatment significantly increased the farnesoid X receptor (FXR) protein expression of ileum, and decreased the TLR4/NF-κB signaling pathway-related messenger RNA (mRNA) and proteins (TLR4, MyD88, p-p65, and p-IκBα) expression in livers of AFB1-exposed mice. Subsequently, pretreatment by Gly-β-MCA, an intestine-selective FXR inhibitor, blocked the alleviating effect of MT on liver injury through increasing the liver-specific expression of TLR4/NF-κB signaling pathway-related mRNA and proteins (TLR4, MyD88, p-p65, and p-IκBα). In conclusion, MT pretreatment ameliorated AFB1-induced liver injury and the potential mechanism may be related to regulate gut microbiota/intestinal FXR/liver TLR4 signaling axis, which provides a strong evidence for the protection of gut-derived liver inflammation.

Interactions between Tryptophan Metabolism, the Gut Microbiome and the Immune System as Potential Drivers of Non-Alcoholic Fatty Liver Disease (NAFLD) and Metabolic Diseases

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing and therefore is its burden of disease as NALFD is a risk factor for cirrhosis and is associated with other metabolic conditions such as type II diabetes, obesity, dyslipidaemia and atherosclerosis. Linking these cardiometabolic diseases is a state of low-grade inflammation, with higher cytokines and c-reactive protein levels found in individuals with NAFLD, obesity and type II diabetes. A possible therapeutic target to decrease this state of low-grade inflammation is the metabolism of the essential amino-acid tryptophan. Its three main metabolic pathways (kynurenine pathway, indole pathway and serotonin/melatonin pathway) result in metabolites such as kynurenic acid, xanturenic acid, indole-3-propionic acid and serotonin/melatonin. The kynurenine pathway is regulated by indoleamine 2,3-dioxygenase (IDO), an enzyme that is upregulated by pro-inflammatory molecules such as INF, IL-6 and LPS. Higher activity of IDO is associated with increased inflammation and fibrosis in NAFLD, as well with increased glucose levels, obesity and atherosclerosis. On the other hand, increased concentrations of the indole pathway metabolites, regulated by the gut microbiome, seem to result in more favorable outcomes. This narrative review summarizes the interactions between tryptophan metabolism, the gut microbiome and the immune system as potential drivers of cardiometabolic diseases in NAFLD.

Potential protective mechanism of Tibetan kefir underlying gut-derived liver injury induced by ochratoxin A

Tibetan kefir against Ochratoxin A-induced liver injury by maintaining the intestinal barrier and modulating the gut microbiota and metabolites.

Melatonin and Pathological Cell Interactions: Mitochondrial Glucose Processing in Cancer Cells

Melatonin is synthesized in the pineal gland at night. Since melatonin is produced in the mitochondria of all other cells in a non-circadian manner, the amount synthesized by the pineal gland is less than 5% of the total. Melatonin produced in mitochondria influences glucose metabolism in all cells. Many pathological cells adopt aerobic glycolysis (Warburg effect) in which pyruvate is excluded from the mitochondria and remains in the cytosol where it is metabolized to lactate. The entrance of pyruvate into the mitochondria of healthy cells allows it to be irreversibly decarboxylated by pyruvate dehydrogenase (PDH) to acetyl coenzyme A (acetyl-CoA). The exclusion of pyruvate from the mitochondria in pathological cells prevents the generation of acetyl-CoA from pyruvate. This is relevant to mitochondrial melatonin production, as acetyl-CoA is a required co-substrate/co-factor for melatonin synthesis. When PDH is inhibited during aerobic glycolysis or during intracellular hypoxia, the deficiency of acetyl-CoA likely prevents mitochondrial melatonin synthesis. When cells experiencing aerobic glycolysis or hypoxia with a diminished level of acetyl-CoA are supplemented with melatonin or receive it from another endogenous source (pineal-derived), pathological cells convert to a more normal phenotype and support the transport of pyruvate into the mitochondria, thereby re-establishing a healthier mitochondrial metabolic physiology.

Melatonin as Immune Potentiator for Enhancing Subunit Vaccine Efficacy against Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus (BVDV) is a pathogen associated with substantial economic losses in the dairy cattle industry. Currently, there are no effective vaccines against BVDV. Melatonin (MT) has been shown to have anti-inflammatory and anti-viral properties, and the use of MF59 in vaccines significantly enhances vaccine efficiency. Here, MT and MF59 were added into the E^rns-LTB vaccine. Subsequently, their inhibitory activity on the NF-κB signaling pathway in Mardin-Darby Bovine Kidney cells and the hippocampus was assessed using western blot and quantitative reverse transcription PCR. The findings revealed that MT in the E^rns-LTB vaccine decreases the phosphorylation of p65 proteins caused by BVDV infection. In addition, MT decreased the mRNA levels of IL-1β and IL-6 in vitro, but increased the production of IFN-α, IFN-β, Mx1 in vitro, brain-derived neurotrophic factor, cyclic amp response element-binding protein, and the stem cell factor in vivo. Furthermore, treatment with E^rns-LTB + MF59 + MT stimulated the production of T lymphocytes, alleviated pathological damage, decreased expressions of BVDV antigen, and tight junction proteins in mice. These findings imply that MT has potential for use in the E^rns-LTB vaccine to inhibit BVDV infection and regulate the immune responses of T-cells by inhibiting the NF-κB signaling pathway.

Hepatotoxicity of food-borne mycotoxins: molecular mechanism, anti-hepatotoxic medicines and target prediction

Mycotoxins are metabolites produced by fungi. The widespread contamination of food and feed by mycotoxins is a global food safety problem and a serious threat to people's health. Most food-borne mycotoxins have strong hepatotoxicity. However, no effective methods have been found to prevent or treat Mycotoxin- Induced Liver Injury (MILI) in clinical and animal husbandry. In this paper, the molecular mechanisms and potential anti-MILI medicines of six food-borne MILI are reviewed, and their targets are predicted by network toxicology, which provides a theoretical basis for further study of the toxicity mechanism of MILI and the development of effective strategies to manage MILI-related health problems in the future and accelerate the development of food safety.