T-2 toxin upregulates the expression of human cytochrome P450 1A1 (CYP1A1) by enhancing NRF1 and Sp1 interaction

WTAP Regulates SOX1 Expression to Affect the Tumorigenicity of Colorectal Cancer via an m6A-YTHDF2-Dependent Manner

BACKGROUND

Wilms tumor 1-associated protein (WTAP) plays a critical role in various cancers, including colorectal cancer (CRC). However, the biological function and molecular mechanisms of WTAP in CRC remain to be elucidated.

METHODS

We determined the expression of WTAP and its correlation with unfavorable prognosis of CRC using RNA-seq and the UALCAN dataset. And we investigated the effects of WTAP on CRC cells using cell proliferation assay, colony formation, cell migration and invasion, and subcutaneous xenograft experiments. We then knockdown of WTAP to identify candidate targets of WTAP. Moreover, the mRNA stability of SRY-box transcription factor 1 (SOX1) was assessed by overexpressing YTHDF2. Finally, we investigated the regulatory mechanism of WTAP in CRC by MeRIP assay, RNA pulldown, dual-luciferase reporter assay, and RIP assay.

RESULTS

We demonstrated that CRC patients with a high expression of WTAP have a risk prognosis. Additionally, WTAP expression can serve as a predictor of survival in CRC. WTAP promoted the proliferation and tumor growth of CRC cells. Moreover, WTAP has been recognized as the upstream regulator of SOX1. WTAP regulated the m6A modification, resulting in the post-transcriptional inhibition of SOX1. YTHDF2 plays a role in promoting mRNA degradation. Then, SOX1 can hinder the progression of CRC. Furthermore, WTAP can regulate the proliferation, migration, and invasion of CRC cells by SOX1 via an m6A-YTHDF2-dependent manner.

CONCLUSION

Our findings demonstrate that WTAP-mediated m6A modification facilitated the progression of CRC through the YTHDF2-SOX1 axis and could serve as a potential therapeutic targeting for CRC.

Identification of Biotransformation Products of T-2 Toxin in HepG2 Cells Using LC-Q-TOF MS

The T-2 toxin (T-2) is a type A trichothecene found in cereals. The formation of metabolites is a frequent cause of mycotoxin-induced toxicity. In this work, the conversion of T-2 during biotransformation reactions in HepG2 cells was evaluated. For this, HepG2 cells were exposed to 30 (IC50/2) and 60 (IC50) nM of T-2 for 0, 1, 2, 3, 6, 8 and 24 h, and the concentrations of T-2 and its metabolites HT-2, T2-triol, T2-tetraol and neosolaniol were determined in both the cell fraction and culture medium through liquid chromatography coupled to high-resolution mass spectrometry-time of flight (LC-Q-TOF MS). Results showed a fast metabolization of T-2 (>90%) during the first 2 h, with HT-2 as its main (>95%) biotransformation product. The cell fraction showed higher levels (p < 0.05) of HT-2 (39.9 ± 2.1 nM) compared to the culture medium (12.53 ± 2.4 nM). This trend was also observed for the identified metabolites. T2-triol reached its maximum concentration (1.7 ± 0.4 nM) at 2 h, and at later times a time-dependent increase in the T2-tetraol and neosolaniol concentrations was observed. The identification of T-2 metabolites shows the need to continue combined toxicity studies of mycotoxins for a correct risk characterization of these natural contaminants.

Effective protective agents against the organ toxicity of T-2 toxin and corresponding detoxification mechanisms: A narrative review

T-2 toxin is one of the most widespread and toxic fungal toxins in food and feed. It can cause gastrointestinal toxicity, hepatotoxicity, immunotoxicity, reproductive toxicity, neurotoxicity, and nephrotoxicity in humans and animals. T-2 toxin is physicochemically stable and does not readily degrade during food and feed processing. Therefore, suppressing T-2 toxin-induced organ toxicity through antidotes is an urgent issue. Protective agents against the organ toxicity of T-2 toxin have been recorded widely in the literature, but these protective agents and their molecular mechanisms of detoxification have not been comprehensively summarized. In this review, we provide an overview of the various protective agents to T-2 toxin and the molecular mechanisms underlying the detoxification effects. Targeting appropriate targets to antagonize T-2 toxin toxicity is also an important option. This review will provide essential guidance and strategies for the better application and development of T-2 toxin antidotes specific for organ toxicity in the future.

T-2 toxin metabolism and its hepatotoxicity: New insights on the molecular mechanism and detoxification

T-2 toxin, a type A trichothecene, is a secondary metabolite produced by Fusarium poae, Fusarium sporotrichioides, and Fusarium tricinctum. As the most toxic trichothecenes, T-2 toxin causes severe damage to multiple organs, especially to liver. However, the contamination of T-2 toxin covers a wide range of plants, including nuts, grains, fruits and herbs globally. And due to chemical stability of T-2 toxin, it is difficult to be completely removed from the food and feeds, which poses a great threat to human and animal health. Liver is the major detoxifying organ which also makes it the main target of T-2 toxin. After being absorbed by intestine, the first pass effect will reduce the level of T-2 toxin in blood indicating that liver is the main metabolic site of T-2 toxin in vivo. In this review, updated researches on the hepatotoxicity of T-2 toxin were summarized. The metabolic characteristic of T-2 toxin in vivo was introduced. The main hepatotoxic mechanisms of T-2 toxin are oxidative stress, mitochondrial damage, deoxyribonucleic acid (DNA) methylation, autophagy and apoptosis. Recent research of the main hepatotoxic mechanisms of T-2 toxin and the interactions between these mechanisms were summarized. The remission of the hepatotoxicity induced by T-2 toxin was also studied in this review followed by new findings on the detoxification of hepatotoxicity induced by T-2 toxin. The review aimed to offer a comprehensive view and proposes new perspectives in the field of hepatotoxicity induced by T-2 toxin.

TET3-mediated DNA demethylation and chromatin remodeling regulate T-2 toxin-induced human CYP1A1 expression and cytotoxicity in HepG2 cells

T-2 toxin is a hazardous environmental pollutant that poses a risk to both farm animals and humans. Our previous research has reported that T-2 toxin highly induced the expression of human cytochrome P450 1A1 (CYP1A1), which may be a representative inducible marker of T-2 toxin and mediate the toxicity of T-2 toxin. In this study, we found that T-2 toxin decreased the DNA methylation levels of the CpG islands on the CYP1A1 promoter by inducing the expression of eleven translocation family protein 3 (TET3) and facilitating its binding to the promoter. These DNA methylation changes then generated an activated chromatin structure on the CYP1A1 promoter by releasing the repressor complex methyl-binding protein 2 (MeCP2) and histone deacetylase 2 (HDAC2), increasing the active histone modification markers, including H3K4ac, H3K9ac and H3K14ac, and facilitating RNA pol II and NRF1/Sp1 recruitment, which ultimately led to the transcriptional activation of CYP1A1. Interestingly, TET3-mediated CYP1A1 induction enhanced the cytotoxicity of T-2 toxin through inhibiting cell proliferation. Our results demonstrate that T-2 toxin-induced CYP1A1 expression is detrimental to cells and clearly show how T-2 toxin inhibits cell proliferation through regulating CYP1A1 expression from an epigenetic perspective. The findings broaden our current knowledge of the epigenetic mechanisms regulating environmental factors-induced CYP1A1 expression and cytotoxicity. TET3 may serve as a potential new target for toxicogenic detoxification.

Network pharmacology-based analysis of heat clearing and detoxifying drug JC724 on the treatment of colorectal cancer

BACKGROUND

Heat-clearing and detoxifying drugs has protective effect on colorectal cancer (CRC). Given the complicated features of Traditional Chinese medicine formulas, network pharmacology is an effective approach for studying the multiple interactions between drugs and diseases.

AIM

To systematically explore the anticancer mechanism of heat-clearing and detoxifying drug JC724.

METHODS

This study obtained the active compounds and their targets in JC724 from Traditional Chinese Medicine System Pharmacology Database. In addition, the CRC targets were obtained from Drugbank, TTD, DisGeNET and GeneCards databases. We performed transcriptome analysis of differentially expressed genes in CRC treated with JC724. Venn diagram was used to screen the JC724-CRC intersection targets as candidate targets. Core targets were selected by protein-protein interaction network and herb ingredient-target-disease network analysis. The functional and pathway of core targets were analysed by enrichment analysis.

RESULTS

We found 174 active ingredients and 283 compound targets from JC724. 940 CRC-related targets were reserved from the four databases and 304 CRC differentially expressed genes were obtained by transcriptome analysis. We constructed the network and found that the five core ingredients were quercetin, β Beta sitosterol, wogonin, kaempferol and baicalein. The core JC724-CRC targets were CYP1A1, HMOX1, CXCL8, NQO1 and FOSL1. JC724 acts on multiple signaling pathways associated with CRC, including the Nrf2 signaling pathway, oxidative stress, and the IL-17 signaling pathway.

CONCLUSION

In this study, we systematically analyzed the active ingredients, core targets and main mechanisms of JC724 in the treatment of CRC. This study could bring a new perspective to the heat-clearing and detoxifying therapy of CRC.

Low dose of arsenic exacerbates toxicity to mice and IPEC-J2 cells exposed with deoxynivalenol: Aryl hydrocarbon receptor and autophagy might be novel therapeutic targets

Deoxynivalenol (DON) and arsenic (As) are widespread environmental contaminants, which are frequently found in human and animal food products. The intestine is a common target of As and DON when they are digested. Numerous studies mainly evaluate the individual effects whereas their combined toxicity has rarely been elucidated. Hence, this study was to assess the effect of low dose of NaAsO₂ on DON-induced intestinal damage and explore the underling mechanism in mice and IPEC-J2 cells. The results showed that low dose of NaAsO₂ exacerbated DON-induced intestinal impairment by increasing intestinal permeability and decreasing the abundance of tight junction proteins (ZO-1, Occludin, Claudin-1). Further, low dose of NaAsO₂ enhanced the AhR signaling pathway and autophagy-related mRNA/protein expressions induced by DON. Interestingly, FICZ, an AhR activator, instead of CH223191, an AhR inhibitor, could alleviate toxicity of the low dose of NaAsO₂ in the mice and IPEC-J2 cells. Compared to the WT IPEC-J2 cells, the intestinal barrier damage was more serious in LC3B^-/- IPEC-J2 cells induced by low dose of NaAsO₂ combination with DON. Collectively, our study demonstrated that low dose of NaAsO₂ exacerbated DON-induced intestinal barrier impairment in vivo and in vitro. The present study also demonstrated that activation of AhR-mediated autophagy might be a self-protection mechanism. Hence, AhR and autophagy might be novel therapeutic targets to prevent or alleviate NaAsO₂ combined with DON-induced intestinal barrier impairment.

Integrated Metabolomics and Transcriptomics Analyses Reveal Metabolic Mechanisms in Porcine Intestinal Epithelial Cells under Zearalenone Stress

Zearalenone (ZEA) is a mycotoxin that frequently occurs in agricultural crops and related products and seriously threatens both animal feed and human food safety. To identify key metabolites and regulators involved in ZEA toxicological processes, we performed metabolomic and transcriptomic analyses of porcine IPEC-J2 intestinal epithelial cells upon ZEA exposure using liquid chromatography-mass spectrometry (LC-MS)/MS and RNA-seq techniques. A total of 325 differential metabolites and 5646 differentially expressed genes were detected. Integrated analyses of metabolomic and transcriptomic data indicated that metabolic processes including lipid metabolism, amino acid metabolism, and carbohydrate metabolism were most affected. Exogenous addition of the key metabolite l-arginine significantly facilitated ZEA metabolism and ameliorated ZEA-induced reactive oxygen species levels and cell apoptosis. Furthermore, l -arginine contributed to the expression of phase II detoxification genes (SULT2B1, GSTA1, GSTM3, and GPX4). l-Arginine addition also increased the protein levels of LC3-II and Beclin 1, and downregulated p62/SQSTM1 levels, indicating its regulatory roles in autophagic flux activation upon ZEA exposure. This study provided global insights into metabolic and transcriptional changes as well as key metabolites and regulators underlying the cellular response to ZEA exposure, and paved the way for the identification of metabolic and molecular targets for biomonitoring and controlling contamination by ZEA.

Role of DNA methylation-related chromatin remodeling in aryl hydrocarbon receptor-dependent regulation of T-2 toxin highly inducible Cytochrome P450 1A4 gene

Mycotoxins are toxic secondary metabolites produced by food-contaminating fungi, which lead to global epigenetic changes and cause toxicity to both farm animals and humans. However, whether mycotoxins induce gene-specific epigenetic alterations associated with inducible downstream gene expression is unclear as are the underlying regulatory mechanisms. Here, we found that T-2 toxin and its deacetylated metabolites but not deoxynivalenol (DON) or other representative mycotoxins highly induced the expression of cytochrome P450 1A4 (CYP1A4) in both Leghorn male hepatoma (LMH) cells and chicken primary hepatocytes, and this effect was related to the regulation of both aryl hydrocarbon receptor (AhR) and DNA methylation. We used methylation-sensitive restriction enzyme digestion-qPCR (MSRE-qPCR) and chromatin immunoprecipitation (ChIP) assays and found that the binding of DNA methyltransferase 1 (DNMT1) and histone deacetylase 2 (HDAC2) to highly methylated CpG island 3-2 at the enhancer of CYP1A4 was accompanied by the recruitment of the repressive histone modification marker H3K27me3, inducing a silent state. In turn, T-2 toxin stimulation enriched the binding of AhR to demethylated CpG island 3-2, which facilitated p300 and H3K9ac recruitment and ultimately generated an activated chromatin structure at the enhancer by increasing the active histone modification markers, including H3K4me3, H3K27ac, and H3K14ac. Interestingly, T-2 toxin-induced AhR activation also facilitated RNA polymerase II binding to CpG island 2, which may form a transcriptionally active chromatin structure at the promoter and ultimately transactivate CYP1A4. Our findings provide novel insights into the epigenetic regulation of T-2 toxin-induced gene expression.

An update on T-2 toxin and its modified forms: metabolism, immunotoxicity mechanism, and human exposure assessment

T-2 toxin is the most toxic trichothecene mycotoxin, and it exerts potent toxic effects, including immunotoxicity, neurotoxicity, and reproductive toxicity. Recently, several novel metabolites, including 3',4'-dihydroxy-T-2 toxin and 4',4'-dihydroxy-T-2 toxin, have been uncovered. The enzymes CYP3A4 and carboxylesterase contribute to T-2 toxin metabolism, with 3'-hydroxy-T-2 toxin and HT-2 toxin as the corresponding primary products. Modified forms of T-2 toxin, including T-2-3-glucoside, exert their immunotoxic effects by signaling through JAK/STAT but not MAPK. T-2-3-glucoside results from hydrolyzation of the corresponding parent mycotoxin and other metabolites by the intestinal microbiota, which leads to enhanced toxicity. Increasing evidence has shown that autophagy, hypoxia-inducible factors, and exosomes are involved in T-2 toxin-induced immunotoxicity. Autophagy promotes the immunosuppression induced by T-2 toxin, and a complex crosstalk between apoptosis and autophagy exists. Very recently, "immune evasion" activity was reported to be associated with this toxin; this activity is initiated inside cells and allows pathogens to escape the host immune response. Moreover, T-2 toxin has the potential to trigger hypoxia in cells, which is related to activation of hypoxia-inducible factor and the release of exosomes, leading to immunotoxicity. Based on the data from a series of human exposure studies, free T-2 toxin, HT-2 toxin, and HT-2-4-glucuronide should be considered human T-2 toxin biomarkers in the urine. The present review focuses on novel findings related to the metabolism, immunotoxicity, and human exposure assessment of T-2 toxin and its modified forms. In particular, the immunotoxicity mechanisms of T-2 toxin and the toxicity mechanism of its modified form, as well as human T-2 toxin biomarkers, are discussed. This work will contribute to an improved understanding of the immunotoxicity mechanism of T-2 toxin and its modified forms.

Protective effect of selenomethionine on intestinal injury induced by T- 2 toxin

T-2 toxin is the most toxic as a type A trichothecenes, which could contaminate grains, especially in wheat and corn. It can cause immune suppression, neurotoxicity, the apoptosis of cells and even induce tumorigenesis. Recent studies have indicated that selenium (Se) have protective effect against mycotoxins-induced toxicity. The present studies was designed to investigate the protective role of Selenomethionine (SeMet) on T-2 toxin-induced toxicity in rabbit's jejunum. 50 New Zealand rabbits were divided into five group (Control group, T-2 group, low-dose Se + T-2 group, medium-dose + T-2 group and high-dose Se + T-2 group). New Zealand rabbits were orally administered with SeMet (0.2, 0.4 and 0.6 mg/kg, Adding diet) for 21 days. On 17th days, each group began to take 0.4 mg/kg of T-2 toxin orally every day for 5 days. We found that rabbit exposed to T-2 toxin could increase the levels of ROS, and decrease activities of antioxidant enzymes and the expression of Occludin and ZO-1. In addition, T-2 toxin could trigger jejunal inflammatory response and enhance the expression of IL-1β, IL-6 and TNF-α. After SeMet pretreatment, our results indicated that Se attenuated the T-2 toxin-induced oxidative stress, decreasing the level of ROS, MDA and enhancing the activity of SOD and GSH-Px. Moreover, SeMet can alleviate jejunal inflammatory response, and protect the integrity of the intestinal barrier through up-regulating the expression of ZO-1 and Occludin. In the present research, supplementation of 0.2 mg/kg SeMet in the diet could effectively alleviate the T-2 toxin poisoning in rabbits.

T-2 toxin neurotoxicity: role of oxidative stress and mitochondrial dysfunction

Mycotoxins are highly diverse secondary metabolites produced in nature by a wide variety of fungi. Mycotoxins cause animal feed and food contamination, resulting in mycotoxicosis. T-2 toxin is one of the most common and toxic trichothecene mycotoxins. For the last decade, it has garnered considerable attention due to its potent neurotoxicity. Worryingly, T-2 toxin can cross the blood-brain barrier and accumulate in the central nervous system (CNS) to cause neurotoxicity. This review covers the current knowledge base on the molecular mechanisms of T-2 toxin-induced oxidative stress and mitochondrial dysfunction in the CNS. In vitro and animal data have shown that induction of reactive oxygen species (ROS) and oxidative stress plays a critical role during T-2 toxin-induced neurotoxicity. Mitochondrial dysfunction and cascade signaling pathways including p53, MAPK, Akt/mTOR, PKA/CREB and NF-κB contribute to T-2 toxin-induced neuronal cell death. T-2 toxin exposure can also result in perturbations of mitochondrial respiratory chain complex and mitochondrial biogenesis. T-2 toxin exposure decreases the mitochondria unfolded protein response and dampens mitochondrial energy metabolism. Antioxidants such as N-acetylcysteine (NAC), activation of Nrf2/HO-1 and autophagy have been shown to provide a protective effect against these detrimental effects. Clearly, translational research and the discovery of effective treatment strategies are urgently required against this common food-borne threat to human health and livestock.