Genome-Scale CRISPR Knockout Screening Identifies BACH1 as a Key Regulator of Aflatoxin B1-Induced Oxidative Damage

CRISPR screening identifies protein methylation and ubiquitination modifications that modulate aflatoxin B1 cytotoxicity

Aflatoxin B1 (AFB1) is one of the most potent mycotoxins affecting human health and animal production. To deeply understand the host-toxin interaction, we performed CRISPR screening and identified cystathionine β-synthase (CBS) as a critical host gene affecting AFB1 cytotoxicity. Mechanistic studies revealed that CBS affects AFB1-induced cell death by regulating the abundance of protein post-translational modifications (PTMs) in host cells. First, AFB1 disrupted the transfer of S-adenosylmethionine (SAM) from the cytoplasm to the mitochondria, thereby reducing the intra-mitochondrial protein methylation level. Deficient intra-mitochondrial protein methylation impaired mitochondrial function and caused cell death. CBS knockout (KO) can enhance SAM generation and mobilization to restore intra-mitochondrial SAM levels by rescuing the perturbed methionine cycle after AFB1 exposure, thereby alleviating AFB1-induced cell death. Second, AFB1 decreased global protein ubiquitination levels by affecting gene expression of ubiquitin-modified enzymes. CBS-KO and pharmaceutical treatment correcting gene expression of ubiquitin-modified enzymes can rescue AFB1-induced cell death. We also investigated two PTM-regulating small molecules, SAM and PR-619, which can increase cell viability in AFB1-exposed cells.

A novel zearalenone lactonase can effectively mitigate zearalenone-induced reproductive toxicity in gilts

Zymdetox Z-2000 is a novel zearalenone (ZEN) lactonase produced by Bacillus subtilis that can biodegrade ZEN to hydrolyzed ZEN and decarboxylated hydrolyzed ZEN with much lower estrogenic activity. This study aims to evaluate the efficacy of Zymdetox Z-2000 in mitigating the adverse effects of ZEN on the growth performance and reproductive health of gilts. A total of 80 crossbred Landrace × Yorkshire gilts (9.82 ± 0.79 kg) were allocated into five groups and received a basal diet (BD; CON), BD supplemented with 0.4 mg/kg ZEN (ZEN), BD plus ZEN with 0.01% Zymdetox Z-2000 (ZEN-Zym), BD plus ZEN with 0.01% coated Zymdetox Z-2000 (ZEN-CoZym), and BD plus ZEN with 0.1% B. subtilis (ZEN-Bs), respectively, for 28 days. Compared to the CON group, ZEN treatment reduced the body weight gain of the gilts, increased vulva area and vaginal and uterus indices, and increased serum aspartate aminotransferase (AST) activity and estradiol (E2) concentration. ZEN treatment also induced ovaries histopathology changes, decreased the total antioxidant capacity (T-AOC) in uterus but increased T-AOC in ovaries, and increased ZEN concentration in stomach and duodenum than those of the CON group. Interestingly, dietary supplementation with the three products effectively alleviated these ZEN-induced adverse effects, as Zymdetox Z-2000 and coated Zymdetox Z-2000 showed better mitigating effects than B. subtilis. In conclusion, ZEN exposure impaired the growth and reproductive health of gilts, while dietary supplementation with Zymdetox Z-2000 and coated Zymdetox Z-2000 can effectively alleviate ZEN-induced reproductive toxicity in gilts.

Flavuside B exhibits antioxidant and anti-inflammatory properties in Staphylococcus aureus infected skin wound and affect the expression of genes controlling bacterial quorum sensing

AIMS

The aim of this study was to evaluate the antioxidant and anti-inflammatory effects of marine fungal cerebroside flavuside B (FlaB) on Staphylococcus aureus-infected keratinocytes in in vitro skin wounds and to identify FlaB targets in bacterial and human cells.

METHODS AND RESULTS

A combination of enzyme-linked immunosorbent assay (ELISA), plate spectrofluorimetry, and flow cytometry with fluorescence dye staining, scratch assay, and real-time cell imaging techniques was used to investigate the effects of FlaB on S. aureus-infected HaCaT keratinocytes. FlaB decreased reactive oxygen species levels, nitrite oxide levels, and TNF-α and IL-18 release in S. aureus-infected HaCaT cells. FlaB reversed the inhibition of HaCaT cell proliferation caused by S. aureus infection. FlaB significantly increased keratinocyte migration and wound healing in an in vitro S. aureus-infected wound skin model. Using real-time qPCR, we found that FlaB caused a 1.7-fold reduction in agrA expression, which controls quorum sensing system in S. aureus. Bioinformatics analysis and molecular docking, together with experimental data, suggest that FlaB targets the pro/antioxidant defense system in human cells.

CONCLUSIONS

Thus, FlaB can play a dual role as an antibacterial and pro/antioxidant machinery modulator, providing an observable positive effect in S. aureus-infected in vitro skin wounds. Staphylococcal sortase A enzyme and Arg systems are the targets of FlaB in bacterial cells. Nrf2/Bach1 dependent pro/antioxidant defense system is a target of FlaB in human cells. Some suggestions have also been made regarding the biological role of this marine fungal metabolite and its therapeutic possibilities.

Development and Evaluation of Non-Antibiotic Growth Promoters for Food Animals

The widespread utilization of antibiotic growth promoters (AGPs) boosts the growth rate of food animals and enhances human living standards. Nevertheless, it is accompanied by escalating antibiotic resistance. Consequently, there is an urgent demand to develop novel alternatives to growth promoters. The objective of this study was to develop a non-antibiotic growth promoter (NAGP) for augmenting the growth rate of food animals. The growth-promoting effect of plant-derived NAGPs was assessed in mice and broiler chickens, and its growth-promoting mechanism was initially investigated. The results reveal that a combination of hawthorn (also known as shanzha) and astragalus (also known as huangqi) extracts (SQ) enhanced the growth rate of mice both in vivo and in vitro, attributed to their significant capacity to promote muscle growth and improve immunity (p < 0.05). The composite super energy extract M (CSEE-M), further optimized on the basis of SQ, significantly improved growth performance and feed conversion ratio, and elevated the activity of intestinal digestive enzymes (p < 0.05) in both mice and broilers and reshaped the gut microbiota of broilers. The addition of 0.5% CSEE-M to broiler drinking water significantly increased muscle content and improved carcass quality (p < 0.05). In conclusion, both SQ and CSEE-M hold great promise as NAGPs and serve as effective substitutes to AGPs. This research not only furnishes new solutions for the misuse of antibiotics but presents a fresh perspective for the development of growth promoters.

Dietary Chlorella vulgaris mitigates aflatoxin B1 toxicity in broiler chicken: Toxicopathological, hematobiochemical and immunological perspectives

Mycotoxins are the chemical substances, produced as the secondary metabolites of some toxigenic species of fungi which cause critical health issues in humans, birds and different animal species while Chlorella vulgaris (CV) is a unicellular microalga which contains plenty of important nutritional ingredients. This study was planned to evaluate the toxicopathological, hematobiochemical and immune changes incurred by dietary supplementation of aflatoxin B1 (AFB1) and their mitigation through CV in broilers. For this study to be conducted, 180 broiler birds of one day old were uniformly distributed into six (06) groups and administered various combinations of AFB1 (200 μg/kg) or CV (0.5 and 1.0%) and the duration of the experiment was 42 days. Parameters deliberated were body weight, feed intake, relative visceral organ weights, gross and histopathological examination, hematological parameters (erythrocytic and leukocytic count, hematocrit and hemoglobin), serum biochemical analysis (serum total proteins, ALT, globulin, albumin, creatinine and urea), humoral response against sheep RBCs, response to subcutaneous injection of phytohemagglutinin-P and phagocytic system function assay. The results of this experiment confirmed that 1.0% CV efficiently mitigated AFB1 induced alterations in the studied parameters while this mitigation was partial when 0.5% CV was used with AFB1. Further studies in this regard are still needed to investigate the exact AFB1:CV ratio responsible for complete amelioration.

Advances in drug-induced liver injury research: in vitro models, mechanisms, omics and gene modulation techniques

Drug-induced liver injury (DILI) refers to drug-mediated damage to the structure and function of the liver, ranging from mild elevation of liver enzymes to severe hepatic insufficiency, and in some cases, progressing to liver failure. The mechanisms and clinical symptoms of DILI are diverse due to the varying combination of drugs, making clinical treatment and prevention complex. DILI has significant public health implications and is the primary reason for post-marketing drug withdrawals. The search for reliable preclinical models and validated biomarkers to predict and investigate DILI can contribute to a more comprehensive understanding of adverse effects and drug safety. In this review, we examine the progress of research on DILI, enumerate in vitro models with potential benefits, and highlight cellular molecular perturbations that may serve as biomarkers. Additionally, we discuss omics approaches frequently used to gather comprehensive datasets on molecular events in response to drug exposure. Finally, three commonly used gene modulation techniques are described, highlighting their application in identifying causal relationships in DILI. Altogether, this review provides a thorough overview of ongoing work and approaches in the field of DILI.

Chromatin accessibility and transcriptional landscape in PK-15 cells during early exposure to Aflatoxin B1

Aflatoxin B1 (AFB1) not only causes significant losses in livestock production but also poses a serious threat to human health. It is the most carcinogenic among known chemicals. Pigs are more susceptible to AFB1 and experience a higher incidence. However, the molecular mechanism of the toxic effect of AFB1 remains unclear. In this study, we used assay for transposase-accessible chromatin using sequencing (ATAC-seq) and RNA-seq to uncover chromatin accessibility and gene expression dynamics in PK-15 cells during early exposure to AFB1. We observed that the toxic effects of AFB1 involve signaling pathways such as p53, PI3K-AKT, Hippo, MAPK, TLRs, apoptosis, autophagy, and cancer pathways. Basic leucine zipper (bZIP) transcription factors (TFs), including AP-1, Fos, JunB, and Fra2, play a crucial role in regulating the biological processes involved in AFB1 challenge. Several new TFs, such as BORIS, HNF1b, Atf1, and KNRNPH2, represent potential targets for the toxic mechanism of AFB1. In addition, it is crucial to focus on the concentration of intracellular zinc ions. These findings will contribute to a better understanding of the mechanisms underlying AFB1-induced nephrotoxicity and offer new molecular targets.

Inhibition of Macrophage Pyroptosis─A New Therapeutic Strategy to Alleviate T-2 Toxin-Induced Subacute Liver Injury by Directly Competing with the Key Target

Multiple compounds are related to the development of liver injury, such as toxins, drugs, and environmental pollutants. Although there are reports that the T-2 toxin can cause liver injury, its toxic mechanism remains unclear, which further impedes the development of effective antidotes. In this study, CRISPR-Cas9 genome-wide screening technology was used to identify transformation-related protein 53 inducible nuclear protein 1 (trp53inp1) as a toxic target of the T-2 toxin. Mechanism studies have shown that the T-2 toxin induced pyroptosis of macrophages (J774A.1 cells) by activating the trp53inp1/NF-κB/NLRP3/GSDMD-N pathway, leading to a subacute liver injury. Also, the new drug berberine (BER) identified through virtual screening significantly alleviated the subacute liver injury by competitively binding trp53inp1 via His224; the effect was better than those of the positive control drugs N-acetylcysteine (NAC) and disulfiram (DSF). In summary, the above results indicate that trp53inp1 is a key target for T-2 toxin to induce subacute liver injury and that inhibiting macrophage pyroptosis is a new method for treating liver injury. In addition, this study provides a new method and strategy for the discovery of key disease targets and the search for effective drugs.

In vitro and in vivo assessment of AFB1 and OTA toxic effects and the beneficial role of bioactive compounds. A systematic review

The purpose of this review was to investigate the current knowledge about aflatoxin B1 (AFB1) and ochratoxin A (OTA) toxicity and the possible beneficial role of bioactive compounds by using in vitro and in vivo models. Although AFB1 and OTA were tested in a similar percentage, the majority of studies focused on nephrotoxicity, hepatotoxicity, immune toxicity and neurotoxicity in which oxidative stress, inflammation, structural damage and apoptosis were the main mechanisms of action reported. Conversely, several biological compounds were assayed in order to modulate mycotoxins damage mainly in the liver, brain, kidney and immune system. Among them, pumpkin, curcumin and fermented whey were the most employed. Although a clear progress has been made by using in vivo models, further research is needed to assess not only the toxicity of multiple mycotoxins contamination but also the effect of functional compounds mixture, thereby reproducing more realistic situations for human health risk assessment.

AFB1 Toxicity in Human Food and Animal Feed Consumption: A Review of Experimental Treatments and Preventive Measures

AIMS

The current review aims to outline and summarize the latest research on aflatoxin, with research studies describing natural, herbal and chemical compound applications in animal (pig) models and in vitro cellular studies. Aflatoxin, a carcinogenic toxin metabolite, is produced by Aspergillus flavus in humid environments, posing a threat to human health and crop production. The current treatment involves the prevention of exposure to aflatoxin and counteracting its harmful toxic effects, enabling survival and research studies on an antidote for aflatoxin.

OBJECTIVES

To summarize current research prospects and to outline the influence of aflatoxin on animal forage in farm production, food and crop processing. The research application of remedies to treat aflatoxin is undergoing development to pinpoint biochemical pathways responsible for aflatoxin effects transmission and actions of treatment.

SIGNIFICANCE

To underline the environmental stress of aflatoxin on meat and dairy products; to describe clinical syndromes associated with aflatoxicosis on human health that are counteracted with proposed treatment and preventive interventions. To understand how to improve the health of farm animals with feed conditions.

Transcription factor BACH1 in cancer: roles, mechanisms, and prospects for targeted therapy

Transcription factor BTB domain and CNC homology 1 (BACH1) belongs to the Cap 'n' Collar and basic region Leucine Zipper (CNC-bZIP) family. BACH1 is widely expressed in mammalian tissues, where it regulates epigenetic modifications, heme homeostasis, and oxidative stress. Additionally, it is involved in immune system development. More importantly, BACH1 is highly expressed in and plays a key role in numerous malignant tumors, affecting cellular metabolism, tumor invasion and metastasis, proliferation, different cell death pathways, drug resistance, and the tumor microenvironment. However, few articles systematically summarized the roles of BACH1 in cancer. This review aims to highlight the research status of BACH1 in malignant tumor behaviors, and summarize its role in immune regulation in cancer. Moreover, this review focuses on the potential of BACH1 as a novel therapeutic target and prognostic biomarker. Notably, the mechanisms underlying the roles of BACH1 in ferroptosis, oxidative stress and tumor microenvironment remain to be explored. BACH1 has a dual impact on cancer, which affects the accuracy and efficiency of targeted drug delivery. Finally, the promising directions of future BACH1 research are prospected. A systematical and clear understanding of BACH1 would undoubtedly take us one step closer to facilitating its translation from basic research into the clinic.

Microalgae (Chlorella vulgaris) attenuates aflatoxin-associated renal injury

Introduction: Aflatoxins (AFT) are ubiquitous environmental pollutants that are extremely dangerous for both human beings as well as animals. A safe, effective, and considerate strategy is therefore credited with controlling AFT intoxication. Therefore, our study aimed to evaluate the mitigating properties of Chlorella vulgaris (ChV) against AFT-induced nephrotoxicity and altered egg quality. Methods: Quails were randomized into Control group (receiving a normal diet); ChV group (1 g/kg diet); AFT group (receiving an AFT-containing diet); and the AFT-ChV group were given both treatments. Results and discussion: AFT provoked kidney injury, exhibited by increased renal biochemical parameters and reduced protein levels. Malondialdehyde (MDA) levels dramatically increased as a consequence of AFT exposure, and glutathione (GSH) levels, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were also decreased. Substantial up-modulation of the mRNA expression of the inflammatory cytokines (TNF-α, IL-1β, and IL-6) was additionally reported. Furthermore, AFT residues were detected in the egg compromising its quality and nutritional value. Contrarily, ChV supplemented diet suppressed the AFT-prompted oxidative stress and inflammation, together with enhancing the nutritional value and quality of eggs and decreasing AFT residues. These beneficial impacts are proposed to be attributed to its antioxidant and nutritional ingredients. The molecular docking dynamics confirmed the inflammatory and apoptotic protein targets for ChV. Our findings recommend that adding ChV supplements to foods might guard against nephrotoxicity brought on by AFT exposure.

Remediation Strategies for Mycotoxins in Animal Feed

Mycotoxins occur widely in various animal feedstuffs, with more than 500 mycotoxins identified so far [...].

Implications of the Cultivation of Rosemary and Thyme (Lamiaceae) in Plant Communities for the Development of Antioxidant Therapies

Oxidative stress is the most critical factor in multiple functional disorders' development, and natural antioxidants could protect the human body against it. Our study aims to investigate the polyphenol content of four extracts of two medicinal plants (Rosmarinus officinalis L. and Thymus vulgaris L.) and analyze the correlation with their antioxidant activity. The research was carried out on extracts of rosemary and thyme obtained from species cultivated together in plant communities. Both were compared with extracts from species cultivated in individual crops (control crops). Their polyphenols were determined by spectrophotometric methods (dosage of flavones, phenol carboxylic acids, and total polyphenols) and chromatography (UHPLC-MS and FT-ICR MS). Triterpenic acids were also quantified, having a higher concentration in the thyme extract from the culture. The antioxidant activity of the dry extracts was evaluated in vitro (DPPH, ABTS, and FRAP) and in silico (prediction of interactions with BACH1/BACH2 transcription factors). The concentrations of polyphenols are higher in the extracts obtained from the sources collected from the common crops. These observations were also validated following the chromatographic analysis for some compounds. Statistically significant differences in the increase in the antioxidant effect were observed for the extracts from the common batches compared to those from the individual ones. Following the Pearson analysis, the IC₅₀ values for each plant extract were strongly correlated with the concentration of active phytoconstituents. Molecular docking studies revealed that quercetin could bind to BTB domains of BACH1 and BACH2 transcription factors, likely translating into increased antioxidant enzyme expression. Future studies must validate the in silico findings and further investigate phytosociological cultivation's effects.

Pathophysiological role of BACH transcription factors in digestive system diseases

BTB and CNC homologous (BACH) proteins, including BACH1 and BACH2, are transcription factors that are widely expressed in human tissues. BACH proteins form heterodimers with small musculoaponeurotic fibrosarcoma (MAF) proteins to suppress the transcription of target genes. Furthermore, BACH1 promotes the transcription of target genes. BACH proteins regulate physiological processes, such as the differentiation of B cells and T cells, mitochondrial function, and heme homeostasis as well as pathogenesis related to inflammation, oxidative-stress damage caused by drugs, toxicants, or infections; autoimmunity disorders; and cancer angiogenesis, epithelial-mesenchymal transition, chemotherapy resistance, progression, and metabolism. In this review, we discuss the function of BACH proteins in the digestive system, including the liver, gallbladder, esophagus, stomach, small and large intestines, and pancreas. BACH proteins directly target genes or indirectly regulate downstream molecules to promote or inhibit biological phenomena such as inflammation, tumor angiogenesis, and epithelial-mesenchymal transition. BACH proteins are also regulated by proteins, miRNAs, LncRNAs, labile iron, and positive and negative feedback. Additionally, we summarize a list of regulators targeting these proteins. Our review provides a reference for future studies on targeted drugs in digestive diseases.

Correction: Zhang et al. Genome-Scale CRISPR Knockout Screening Identifies BACH1 as a Key Regulator of Aflatoxin B1-Induced Oxidative Damage. Antioxidants 2022, 11, 1787

In the original publication [...].

The Preferential Therapeutic Potential of Chlorella vulgaris against Aflatoxin-Induced Hepatic Injury in Quail

Aflatoxins (AFs) are the most detrimental mycotoxin, potentially hazardous to animals and humans. AFs in food threaten the health of consumers and cause liver cancer. Therefore, a safe, efficient, and friendly approach is attributed to the control of aflatoxicosis. Therefore, this study aimed to evaluate the impacts of Chlorella vulgaris (CLV) on hepatic aflatoxicosis, aflatoxin residues, and meat quality in quails. Quails were allocated into a control group; the CLV group received CLV (1 g/kg diet); the AF group received an AF-contaminated diet (50 ppb); and the AF+CLV group received both treatments. The results revealed that AF decreased the growth performance and caused a hepatic injury, exhibited as an increase in liver enzymes and disrupted lipid metabolism. In addition, AF induced oxidative stress, exhibited by a dramatic increase in the malondialdehyde (MDA) level and decreases in glutathione (GSH) level, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities. Significant up-regulation in the inflammatory cytokine (TNF-α, IL-1β, and IL-6) mRNA expression was also documented. Moreover, aflatoxin residues were detected in the liver and meat with an elevation of fat% alongside a decrease in meat protein%. On the other hand, CLV supplementation ameliorated AF-induced oxidative stress and inflammatory condition in addition to improving the nutritional value of meat and significantly reducing AF residues. CLV mitigated AF-induced hepatic damage, decreased growth performance, and lowered meat quality via its antioxidant and nutritional constituents.