Patulin: Mechanism of genotoxicity

Patulin alters alpha-adrenergic receptor signalling and induces epigenetic modifications in the kidneys of C57BL/6 mice

Patulin (PAT) is a food-borne mycotoxin produced by Penicillium and Byssochlamys species. It is widely known for its mutagenic, carcinogenic, and genotoxic effects and has been associated with kidney injury; however, the mechanism of toxicity remains unclear. To address this gap, we conducted a study to explore the changes in α-adrenergic receptor signalling pathways and epigenetic modifications induced by PAT in the kidneys of C57BL/6 mice during acute (1 day) and prolonged (10 days) exposure. The mice (20-22 g) were orally administered PAT (2.5 mg/kg; at 1 and 10 days), and post-treatment, the kidneys were harvested, homogenised and extracted for RNA, DNA, and protein. The relative gene expression of the α-adrenergic receptors (ADRA1, ADRA2A, ADRA2B) and associated signalling pathways (MAPK, MAPK14, ERK, PI3K, and AKT) was assessed by qPCR. The protein expression of ERK1/2 and MAPK was determined by western blot. The impact of PAT on DNA methylation was evaluated by quantifying global DNA methylation; qPCR was used to determine gene expression levels of DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B) and demethylase (MBD2). PAT downregulated the expression of ADRA1, ADRA2A, ADRA2B, PI3K, and AKT and upregulated ERK1/2 and MAPK protein expression. Furthermore, PAT induced alterations in DNA methylation patterns by upregulating DNMT1 and MBD2 expressions and downregulating DNMT3A and DNMT3B expressions, resulting in global DNA hypomethylation. In conclusion, PAT disrupts α-1 and α-2 adrenergic receptor signalling pathways and induces epigenetic modifications, that can lead to kidney injury.

Evaluation of the Immune Response of Patulin by Proteomics

Patulin, an emerging mycotoxin with high toxicity, poses great risks to public health. Considering the poor antibody production in patulin immunization, this study focuses on the four-dimensional data-independent acquisition (4D-DIA) quantitative proteomics to reveal the immune response of patulin in rabbits. The rabbit immunization was performed with the complete developed antigens of patulin, followed by the identification of the immune serum. A total of 554 differential proteins, including 292 up-regulated proteins and 262 down-regulated proteins, were screened; the differential proteins were annotated; and functional enrichment analysis was performed. The differential proteins were associated with the pathways of metabolism, gene information processing, environmental information processing, cellular processes, and organismal systems. The functional enrichment analysis indicated that the immunization procedures mostly resulted in the regulation of biochemical metabolic and signal transduction pathways, including the biosynthesis of amino acid (glycine, serine, and threonine), ascorbate, and aldarate metabolism; fatty acid degradation; and antigen processing and presentation. The 14 key proteins with high connectivity included G1U9T1, B6V9S9, G1SCN8, G1TMS5, G1U9U0, A0A0G2JH20, G1SR03, A0A5F9DAT4, G1SSA2, G1SZ14, G1T670, P30947, P29694, and A0A5F9C804, which were obtained by the analysis of protein-protein interaction networks. This study could provide potential directions for protein interaction and antibody production for food hazards in animal immunization.

Structure-Based Design, Virtual Screening, and Discovery of Novel Patulin Derivatives as Biogenic Photosystem II Inhibiting Herbicides

Computer-aided design usually gives inspirations and has become a vital strategy to develop novel pesticides through reconstructing natural lead compounds. Patulin, an unsaturated heterocyclic lactone mycotoxin, is a new natural PSII inhibitor and shows significant herbicidal activity to various weeds. However, some evidence, especially the health concern, prevents it from developing as a bioherbicide. In this work, molecular docking and toxicity risk prediction are combined to construct interaction models between the ligand and acceptor, and design and screen novel derivatives. Based on the analysis of a constructed patulin-Arabidopsis D1 protein docking model, in total, 81 derivatives are designed and ranked according to quantitative estimates of drug-likeness (QED) values and free energies. Among the newly designed derivatives, forty-five derivatives with better affinities than patulin are screened to further evaluate their toxicology. Finally, it is indicated that four patulin derivatives, D3, D6, D34, and D67, with higher binding affinity but lower toxicity than patulin have a great potential to develop as new herbicides with improved potency.

The Dual Roles of Activating Transcription Factor 3 (ATF3) in Inflammation, Apoptosis, Ferroptosis, and Pathogen Infection Responses

Transcription factors are pivotal regulators in the cellular life process. Activating transcription factor 3 (ATF3), a member of the ATF/CREB (cAMP response element-binding protein) family, plays a crucial role as cells respond to various stresses and damage. As a transcription factor, ATF3 significantly influences signal transduction regulation, orchestrating a variety of signaling pathways, including apoptosis, ferroptosis, and cellular differentiation. In addition, ATF3 serves as an essential link between inflammation, oxidative stress, and immune responses. This review summarizes the recent advances in research on ATF3 activation and its role in regulating inflammatory responses, cell apoptosis, and ferroptosis while exploring the dual functions of ATF3 in these processes. Additionally, this article discusses the role of ATF3 in diseases related to pathogenic microbial infections. Our review may be helpful to better understand the role of ATF3 in cellular responses and disease progression, thus promoting advancements in clinical treatments for inflammation and oxidative stress-related diseases.

Patulin Ameliorates Hypertrophied Lipid Accumulation and Lipopolysaccharide-Induced Inflammatory Response by Modulating Mitochondrial Respiration

Patulin (PAT) is a natural mycotoxin found in decaying pome fruits. Although some toxicological studies have been conducted on PAT, recent research has highlighted its anticancer and antifungal effects. However, studies have yet to examine the effects and molecular mechanisms of PAT in other metabolic diseases. Obesity is a chronic disease caused by excessive food intake and abnormal lifestyle, leading to low-grade inflammation. Therefore, this study aimed to elucidate the effect of PAT on obesity at the cellular level. PAT treatment reduced lipid accumulation, suppressed glucose and LDL uptake, inhibited lipid deposition and triglyceride synthesis, upregulated fatty acid oxidation-related genes (Pgc1α), and downregulated adipogenic/lipogenic genes (Pparγ and C/ebpα) in hypertrophied 3T3-L1 adipocytes. Additionally, PAT treatment enhanced mitochondrial respiration and mass in differentiated adipocytes and alleviated inflammatory response in activated RAW 264.7 macrophages. Moreover, PAT treatment downregulated pro-inflammatory genes (il-6, Tnf-α, Cox-2, and inos), suppressed lipopolysaccharide (LPS)-induced increase in inflammatory mediators (IL-6, TNF-α, and NO), and restored mitochondrial oxidative function in LPS-stimulated macrophages by improving oxygen consumption and mitochondrial integrity and suppressing ROS generation. Overall, these findings suggest a potential for PAT in the prevention of lipid accumulation and inflammation-related disorders.

Patulin alleviates hepatic lipid accumulation by regulating lipogenesis and mitochondrial respiration

AIMS

The aim of this study is to evaluate the effects of patulin on hepatic lipid metabolism and mitochondrial oxidative function and elucidate the underlying molecular mechanisms.

MAIN METHODS

The effects of patulin on hepatic lipid accumulation were evaluated in free fatty acid-treated AML12 or HepG2 cells through oil red O staining, triglyceride assay, real-time polymerase chain reaction, and western blotting. Alteration of mitochondrial oxidative capacity by patulin treatment was determined using Seahorse analysis to measure the oxygen consumption rate.

KEY FINDINGS

The increased amounts of lipid droplets induced by free fatty acids were significantly reduced by patulin treatment. Patulin markedly activated the CaMKII/AMP-activated protein kinase (AMPK)/proliferator-activated receptor-γ coactivator (PGC)-1α signaling pathway in hepatocytes, reduced the expression of sterol regulatory element binding protein 1c (SREBP-1c) and lipogenic genes, and increased the expression of genes related to mitochondrial fatty acid oxidation. In addition, patulin treatment enhanced the mitochondrial consumption rate and increased the expression of mitochondrial oxidative phosphorylation proteins in HepG2 hepatocytes. The effects of patulin on anti-lipid accumulation; SREBP-1c, PGC-1α, and carnitine palmitoyltransferase 1 expression; and mitochondrial oxidative capacity were significantly prevented by compound C, an AMPK inhibitor.

SIGNIFICANCE

Patulin is a potent inducer of the AMPK pathway, and AMPK-mediated mitochondrial activation is required for the efficacy of patulin to inhibit hepatic lipid accumulation. This study is the first to report that patulin is a promising bioactive compound that prevents the development and worsening of fatty liver diseases, including non-alcoholic fatty liver disease, by improving mitochondrial quality and lipid metabolism.

Sulfhydryl-functionalized carbon dots as effective probes for fluorescence enhancement detection of patulin

In this study, sulfydryl-functionalized nitrogen-doped carbon dots (SH-NCDs) was synthesized by amide reaction of hydrothermally synthesized carbon dots with l-cysteine and used to detect patulin selectively. The SH-NCDs exhibited excitation wavelength-independent fluorescence in the range 300-360 nm. The modified sulfhydryl group (-SH) on the surface of NCDs served as a specific recognition site to capture patulin. The addition reaction between patulin and the -SH on the SH-NCDs surface resulted in enhanced fluorescence. SH-NCDs was used as a fluorescent probe for label-free detection of patulin, showing excellent sensitivity in the linear range of 0.1-400 ng mL^-1, with detection limits as low as 0.053 ng mL^-1. The fluorescent probe has specific selectivity for patulin. The recoveries of patulin in apple juice and grape juice were 88.9 %-99.2 % and 92.5 %-101.8 %, respectively. These results showed that the sensor designed in this experiment selectively detected the target patulin from complex food systems.

Patulin Alters Insulin Signaling and Metabolic Flexibility in HepG2 and HEK293 Cells

Non-communicable diseases (NCDs) have risen rapidly worldwide, sparking interest in causative agents and pathways. Patulin (PAT), a xenobiotic found in fruit products contaminated by molds, is postulated to be diabetogenic in animals, but little is known about these effects in humans. This study examined the effects of PAT on the insulin signaling pathway and the pyruvate dehydrogenase complex (PDH). HEK293 and HepG2 cells were exposed to normal (5 mM) or high (25 mM) glucose levels, insulin (1.7 nM) and PAT (0.2 μM; 2.0 μM) for 24 h. The qPCR determined gene expression of key enzymes involved in carbohydrate metabolism while Western blotting assessed the effects of PAT on the insulin signaling pathway and Pyruvate Dehydrogenase (PDH) axis. Under hyperglycemic conditions, PAT stimulated glucose production pathways, caused defects in the insulin signaling pathway and impaired PDH activity. These trends under hyperglycemic conditions remained consistent in the presence of insulin. These findings are of importance, given that PAT is ingested with fruit and fruit products. Results suggest PAT exposure may be an initiating event in insulin resistance, alluding to an etiological role in the pathogenesis of type 2 diabetes and disorders of metabolism. This highlights the importance of both diet and food quality in addressing the causes of NCDs.

Cytotoxic and mutagenic effects of the food additive tartrazine on eukaryotic cells

BACKGROUND

Among the food additives used in the food industry, food dyes are considered the most toxic. For instance, tartrazine (TRZ) is a food colorant commercially available with conflicting data regarding its cytotoxic, genotoxic, and mutagenic effects. Therefore, this study aimed to evaluate the cytotoxic and mutagenic potential of TRZ using different eukaryotic cells (in vitro).

METHODS

This study employed 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), brine shrimp lethality, Allium cepa and Saccharomyces cerevisiae tests. Different concentrations of TRZ and different exposure times were used in this study.

RESULTS

The results demonstrate that TRZ induced a concentration-dependent toxic effect on the test systems. It also exerted cytotoxicity in fibroblasts and human gastric cells. In addition, TRZ showed mutagenic effects on the A. cepa test system. However, its toxicogenic effects may not relate to the oxidizing activity, which was confirmed by the S. cerevisiae test model.

CONCLUSION

Taken together, TRZ exerted toxicogenic effects on the test systems. Therefore, it may be harmful to health, especially its prolonged use may trigger carcinogenesis.

Modulation of extracellular Penicillium expansum-driven acidification by Papiliotrema terrestris affects biosynthesis of patulin and has a possible role in biocontrol activity

The active regulation of extracellular pH is critical for the virulence of fungal pathogens. Penicillium expansum is the causal agent of green-blue mold on stored pome fruits and during its infection process acidifies the host tissues by secreting organic acids. P. expansum is also the main producer of patulin (PAT), a mycotoxin found in pome fruit-based products and that represents a serious health hazard for its potential carcinogenicity. While it is known that PAT biosynthesis in P. expansum is regulated by nutritional factors such as carbon and nitrogen and by the pH, the mechanistic effects of biocontrol on PAT production by P. expansum are not known. In this work, we assessed how optimal and suboptimal concentrations of the biocontrol agent (BCA) Papiliotrema terrestris LS28 affect both extracellular pH and PAT biosynthesis in P. expansum. In wounded apples, the optimal and suboptimal concentrations of the BCA provided almost complete and partial protection from P. expansum infection, respectively, and reduced PAT contamination in both cases. However, the suboptimal concentration of the BCA increased the specific mycotoxigenic activity by P. expansum. In vitro, the rate of PAT biosynthesis was strictly related to the extracellular pH, with the highest amount of PAT detected in the pH range 4–7, whereas only traces were detectable at pH 3. Moreover, both in vitro and in apple wounds the BCA counteracted the extracellular P. expansum-driven acidification maintaining extracellular pH around 4, which is within the pH range that is optimal for PAT biosynthesis. Conversely, in the absence of LS28 the pathogen-driven acidification led to rapidly achieving acidic pH values (<3) that lie outside of the optimal pH range for PAT biosynthesis. Taken together, these results suggest that pH modulation by LS28 is important to counteract the host tissue acidification and, therefore, the virulence of P. expansum. On the other hand, the buffering of P. expansum-driven acidification provided by the BCA increases the specific rate of PAT biosynthesis through the extension of the time interval at which the pH value lies within the optimal range for PAT biosynthesis. Nevertheless, the antagonistic effect provided by the BCA greatly reduced the total amount of PAT.

Highly efficient removal of patulin using immobilized enzymes of Pseudomonas aeruginosa TF-06 entrapped in calcium alginate beads

Patulin is a toxic secondary metabolite produced by several moulds, which contaminates fruits and their products posing serious threats to human health. Though several microorganisms and enzymes have been reported to effectively degrade patulin, separation of them from fruit juice challenges the commercial applications. Here, a Pseudomonas aeruginosa strain TF-06 was isolated, its patulin degradation mechanism and optimum conditions for enzyme immobilization were investigated. The results indicated that TF-06 could degrade patulin into non-cytotoxic E/Z-ascladiol mainly by the activity of intracellular enzymes. For easy separation of enzymes, calcium alginate was selected for immobilization of intracellular enzymes from TF-06. The immobilized enzyme beads were effective in detoxification of patulin in apple juice. The mitigation rate was reached 95%, while there was no negative effect on juice quality. The study provides a promising way to resolve the issue of enzyme separation during mycotoxin biological detoxification in fruit juice.

miR-27b inhibition contributes to cytotoxicity in patulin-exposed HEK293 cells

Patulin (PAT) is a mycotoxin produced by Penicillium and other fungi that contaminate fruit. PAT targets the kidney and is associated with nephrotoxicity. Micro-RNAs (miRNA) may offer new insights into PAT-induced nephrotoxicity. Cytochrome P₄₅₀ family 1, subfamily B, polypeptide 1 (CYP1B1), involved in metabolism of dietary toxins is negatively regulated by miR-27b and linked with the nuclear factor kappa B (NF-κB) pathway and peroxisome proliferator activated receptor gamma (PPARɣ) in renal fibrosis. This study investigated the effects of PAT on miR-27b, CYP1B1, PPARɣ and cytotoxicity in human kidney (HEK293) cells. HEK293 cells were exposed to PAT (2.5 μM, 24h). Protein expression of CYP1B1, PPARɣ, NF-κB (p65), pNF-κB (p65) (phospho-Ser563) and cleaved PARP-1 was quantified using western blotting. QPCR evaluated mRNA levels of CYP1B1, IL-6, miR-27b, OGG1, mtDNA, TFAM and UCP2. Mitochondrial membrane potential and phosphatidylserine (PS) externalization was evaluated by flow cytometry while levels of ATP and caspase -9, -8, -3/7 activity was measured using luminometry. PAT significantly decreased miR-27b levels (p = 0.0014) and increased CYP1B1 mRNA (p = 0.0015) and protein (p = 0.0013) levels. PPARɣ protein expression was significantly increased (p = 0.0002) and associated with decreased NF-κB activation (p = 0.0273) and IL-6 mRNA levels (p = 0.0265). Finally, PAT significantly compromised mitochondrial repair mechanisms and increased apoptotic biomarkers. PAT altered miR-27b levels and PPARɣ, with associated changes to NF-κB activation, downstream IL-6 and CYP1B1 expression. These results show that PAT impairs detoxification mechanisms leading to mitochondrial damage and apoptosis. In conclusion, PAT altered the epigenetic environment and impaired detoxification processes, supporting a mechanism for nephrotoxic outcomes.

TGF-β/Smad signaling pathway plays a crucial role in patulin-induced pro-fibrotic changes in rat kidney via modulation of slug and snail expression

Patulin (PAT) is a mycotoxin that contaminates a variety of food and foodstuffs. Earlier in vitro and in vivo findings have indicated that kidney is one of the target organs for PAT-induced toxicity. However, no study has evaluated the chronic effects of PAT exposure at environmentally relevant doses or elucidated the detailed mechanism(s) involved. Here, using in vitro and in vivo experimental approaches, we delineated the mechanism/s involved in pro-fibrotic changes in the kidney after low-dose chronic exposure to PAT. We found that non-toxic concentrations (50 nM and 100 nM) of PAT to normal rat kidney cells (NRK52E) caused a higher generation of reactive oxygen species (ROS) (mainly hydroxyl (•OH), peroxynitrite (ONOO^-), and hypochlorite radical (ClO-). PAT exposure caused the activation of mitogen-activated protein kinases (MAPKs) and its downstream c-Jun/Fos signaling pathways. Moreover, our chromatin immunoprecipitation (ChIP) analysis suggested that c-Jun/Fos binds to the promoter region of Transforming growth factor beta (TGF-β₁) and possibly induces its expression. Results showed that PAT-induced TGF-β₁ further activates the TGF-β₁/smad signaling pathways. Higher activation of slug and snail transcription factors further modulates the regulation of pro-fibrotic molecules. Similarly, in vivo results showed that PAT exposure to rats through gavage at 25 and 100 μg/kg b. wt had higher levels of kidney injury/toxicity markers namely vascular endothelial growth factor (VEGF), kidney Injury Molecule-1 (Kim-1), tissue inhibitor of metalloproteinase-1 (Timp-1), and clusterin (CLU). Additionally, histopathological analysis indicated significant alterations in renal tubules and glomeruli along with collagen deposition in PAT-treated rat kidneys. Overall, our data provide evidence of the involvement of ROS mediated MAPKs and TGF-β₁/smad pathways in PAT-induced pro-fibrotic changes in the kidney via modulation of slug and snail expression.

Involvement of caspase in patulin-induced hepatotoxicity in vitro and in vivo

Patulin (PAT) a kind of mycotoxin, is a widely disseminated mycotoxin found in agricultural products and could cause liver damage. However, evidence on the underlying mechanisms of patulin is still lacking. In the present study, Human liver cancer cells (HepG2) together with a mouse model were used to explore the possible effect and mechanism. The results demonstrated that PAT treatment inhibited cell proliferation and caused liver toxicity in mice. In vitro, PAT inhibited the growth of HepG2 cells in a dose-dependent manner and a time-dependent manner; lipid peroxidation, malondialdehyde (MDA) production increased and the level of SOD and GSH in cells changed significantly. In vivo, Kunming mice were treated with PAT(2.5-15 μM), We indicated that liver damage are observed. The activity of serum alanine transaminase (ALT) and aspartate transaminase (AST) were increased significantly, the hepatocyte nucleus stained with Hematoxylin and Eosin (HE) was blurred and deformed. we also explored the lipid peroxidation and enzymes related to redox and found that the activities of SOD in animals do not change significantly, not like that in cells, while GSHpx played a major role. In addition, we measured the caspase activity of cells and the expression of caspase in mice. PAT-induced the caspase cascade was confirmed with the elevation of the activity and expression of caspase. These data suggest that PAT treatment altered both the redox systems in cells and animals. involvement of caspase in patulin-induced hepatotoxicity.

Toxic effects of patulin on mouse oocytes and its possible mechanisms

Patulin is a secondary metabolite mainly secreted by fungi and is the most common mycotoxin found in apples and apple-based products. For the past few years, numerous studies suggested the wide distribution and toxicity of patulin. In this study, we investigated the toxic effect of patulin on mouse oocytes and its possible mechanisms. The results showed that patulin treatment did not affect meiotic resumption, but inhibited oocyte maturation as indicated by failure of first polar body extrusion. Further mechanistic study showed that patulin treatment disturbed normal spindle assembly, chromosome alignment and morphology. We also found increased oxidative stress by testing the level of ROS and decreased mitochondrial membrane potential, indicating mitochondria dysfunction. In summary, our results suggest that patulin treatment causes oocyte meiotic arrest by disturbing normal spindle assembly and chromosome alignment, which may be caused by dysfunctions of mitochondria.

A comparison of the inhibitory activities of Lactobacillus and Bifidobacterium against Penicillium expansum and an analysis of potential antifungal metabolites

The infection of fruits by Penicillium expansum (P. expansum) do not only cause economic loss but also potentially endanger human health, especially because few biocontrol agents against this fungus have been well studied yet. In this work, to verity the antifungal activity against P. expansum of 22 Bifidobacterium and 44 Lactobacillus, dual-culture overlay assay, microtiter plate well assay and agar spot assay were successively performed. One of the strain, Bifidobacterium adolescentis (B. adolescentis) CCFM1108 exhibited the most potent inhibition ability among all tested strains. Additionally, we showed that multiple antifungal compounds produced by tested strain synergistically inhibit the growth of P. expansum, including lactic acid, acetic acid, 3-phenyllactic acid and p-hydroxyphenyllactic acid. Those active compounds mentioned were detected in the cell-free supernatant and characterized by metabolomics analysis using GC-MS. Correspondingly, B. adolescentis CCFM1108 supernatant disrupted plasma membrane integrity of the P. expansum mycelial and drastically reduced patulin production in P. expansum. The inhibitive effects of B. adolescentis CCFM1108 were also confirmed with three other P. expansum strains. The active inhibitory properties of Bifidobacterium strains, especially B. adolescentis CCFM1108, indicate that B. adolescentis can be potentially used as a novel bioagent to prevent or delay fungal spoilage on fruit.

Action Mode of the Mycotoxin Patulin as a Novel Natural Photosystem II Inhibitor

A biocontrol method plays an important role in weed management. In this study, we aimed to clarify the phytotoxicity of the mycotoxin patulin (PAT) and reveal its mode of action as a new natural photosystem II (PSII) inhibitor. Phytotoxicity test showed that PAT has herbicidal activity and causes significant leaf lesions on Ageratina adenophora. Under a half-inhibition concentration I₅₀ (2.24 μM), the observed significant decrease in oxygen evolution rate and the increase in the J-step of the chlorophyll fluorescence rise OJIP curve indicated that PAT strongly reduces photosynthetic efficiency by blocking electron transport from the primary to secondary plastoquinone acceptors (Q_A to Q_B) of PSII. Molecular modeling of PAT docking to the A. adenophora D1 protein suggested that PAT bounds to the Q_B site by forming hydrogen bonds to histidine 252 in the D1 protein. It is proposed that PAT is a new natural PSII inhibitor and has the potential to be developed into a bioherbicide or used as a template scaffold for discovering novel derivatives with more potent herbicidal activity.

Involvement of NADPH oxidase in patulin-induced oxidative damage and cytotoxicity in HEK293 cells

Patulin (PAT) is a kind of mycotoxins that commonly found in decayed fruits and their products. Our previous studies have shown that PAT induced cell apoptosis and the overproduction of reactive oxygen species (ROS) in human embryonic kidney (HEK293) cells. The present study aimed to further investigate the functional role of NADPH oxidase, one of the main cellular sources of ROS, in PAT-induced apoptosis and oxidative damage in HEK293 cells. We demonstrated that the protein and mRNA expression levels of NADPH oxidase catalytic subunit NOX2 and regulatory subunit p47phox were up-regulated under PAT stress. Inhibiting of NADPH oxidase with the specific antagonist diphenyleneiodonium (DPI) suppressed cytotoxicity and apoptosis induced by PAT as evidenced by the increase of cell viability, the decrease of LDH release and the inhibition of caspase activities. Furthermore, DPI re-established mitochondrial membrane potential (MMP) and enhanced cellular ATP content. Importantly, DPI supplementation elevated endogenous GSH contents as well as the ratio of GSH/GSSG. Meanwhile, the antioxidant-enzyme activities of GPx, GR, CAT and SOD were significantly promoted. Collectively, our results suggested that NADPH oxidase played a critical role in PAT-induced nephrotoxicity, and inhibition of NADPH oxidase by DPI attenuated cell injury and apoptosis via regulation of oxidative damage.

Patulin suppresses α1-adrenergic receptor expression in HEK293 cells

Patulin (PAT) is a common mycotoxin contaminant of apple products linked to impaired metabolic and kidney function. Adenosine monophosphate activated protein kinase (AMPK), abundantly expressed in the kidney, intercedes metabolic changes and renal injury. The alpha-1-adrenergic receptors (α₁-AR) facilitate Epinephrine (Epi)-mediated AMPK activation, linking metabolism and kidney function. Preliminary molecular docking experiments examined potential interactions and AMPK-gamma subunit 3 (PRKAG3). The effect of PAT exposure (0.2-2.5 µM; 24 h) on the AMPK pathway and α₁-AR was then investigated in HEK293 human kidney cells. AMPK agonist Epi determined direct effects on the α₁-AR, metformin was used as an activator for AMPK, while buthionine sulphoximine (BSO) and N-acetyl cysteine (NAC) assessed GSH inhibition and supplementation respectively. ADRA1A and ADRA1D expression was determined by qPCR. α₁-AR, ERK1/2/MAPK and PI3K/Akt protein expression was assessed using western blotting. PAT (1 µM) decreased α₁-AR protein and mRNA and altered downstream signalling. This was consistent in cells stimulated with Epi and metformin. BSO potentiated the observed effect on α₁-AR while NAC ameliorated these effects. Molecular docking studies performed on Human ADRA1A and PRKAG3 indicated direct interactions with PAT. This study is the first to show PAT modulates the AMPK pathway and α₁-AR, supporting a mechanism of kidney injury.

Microbiological Detoxification of Mycotoxins: Focus on Mechanisms and Advances

Some fungal species of the genera Aspergillus, Penicillium, and Fusarium secretes toxic metabolites known as mycotoxins, have become a global concern that is toxic to different species of animals and humans. Biological mycotoxins detoxification has been studied by researchers around the world as a new strategy for mycotoxin removal. Bacteria, fungi, yeast, molds, and protozoa are the main living organisms appropriate for the mycotoxin detoxification. Enzymatic and degradation sorptions are the main mechanisms involved in microbiological detoxification of mycotoxins. Regardless of the method used, proper management tools that consist of before-harvest prevention and after-harvest detoxification are required. Here, in this review, we focus on the microbiological detoxification and mechanisms involved in the decontamination of mycotoxins.

Ribonucleoside Diphosphate Reductase Plays an Important Role in Patulin Degradation by Enterobacter cloacae subsp. dissolvens

Patulin contamination is a worldwide concern due to its significant impact on human health. Several yeast strains have been screened for patulin biodegradation; however, little information is available on bacterial strains and their mechanism of degradation. In the present study, we isolated a bacterial strain TT-09 and identified it as Enterobacter cloacae subsp. dissolvens based on the BioLog system and 16S rDNA phylogenetic analysis. The strain was demonstrated to be able to transform patulin into E-ascladiol. Isobaric tags for relative and absolute quantitation and reverse transcription quantitative polymerase chain reaction analyses provided evidence that ribonucleoside diphosphate reductase (NrdA), an important enzyme involved in DNA biosynthesis, plays a crucial role in patulin degradation. Deletion of nrdA resulted in a total loss in the ability to degrade patulin in TT-09. These results indicate a new function for NrdA in mycotoxin biodegradation. The present study provides evidence for understanding a new mechanism of patulin degradation and information that can be used to develop new approaches for managing patulin contamination.

Detoxification of Mycotoxins through Biotransformation

Mycotoxins are toxic fungal secondary metabolites that pose a major threat to the safety of food and feed. Mycotoxins are usually converted into less toxic or non-toxic metabolites through biotransformation that are often made by living organisms as well as the isolated enzymes. The conversions mainly include hydroxylation, oxidation, hydrogenation, de-epoxidation, methylation, glycosylation and glucuronidation, esterification, hydrolysis, sulfation, demethylation and deamination. Biotransformations of some notorious mycotoxins such as alfatoxins, alternariol, citrinin, fomannoxin, ochratoxins, patulin, trichothecenes and zearalenone analogues are reviewed in detail. The recent development and applications of mycotoxins detoxification through biotransformation are also discussed.

Switchable fluorescence sensor toward PAT via CA-MWCNTs quenched aptamer-tagged carboxyfluorescein

A quenching based apta-sensing platform was developed for the detection of Patulin. Three different aptamer sequences were studied to screen the aptamer with the maximum affinity towards Patulin. Carboxyfluorescein (CFL) was used as a fluorescent dye while -COOH functionalized multiwall carbon nanotubes (MWCNTs) were applied as novel nanoquenchers. Aptamer tagged at the 3' end with 40 nucleotide bases exhibited the maximum affinity towards Patulin and caused substantial fluorescence recovery. Interestingly, the limit of detection (LOD) and limit of quantification (LOQ) were calculated as 0.13 μg L^-1and 0.41 μg L^-1 respectively. Commonly occurring mycotoxins in food were also tested to confirm the selectivity of apta-assay. The developed apta-assay was applied to a spiked apple juice sample and toxin recoveries were observed ranging from 96% to 98% (n = 3). These results demonstrated the potential of the developed apta-assay for the selective detection and quantification of Patulin in food samples.

Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo

Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers’ health. Liquid chromatography–tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed for brewing of Namibian beverages, otombo (n = 45) and omalodu (n = 36). Co-occurrence of European Union (EU)-regulated mycotoxins, such as patulin, aflatoxins (B₁, B₂, and G₂), and fumonisins (B₁, B₂, and B₃) was detected in both malts with a prevalence range of 2–84%. Aflatoxin B₁ was quantified in omalodu (44%) and otombo malts (14%), with 20% of omalodu malts and 40% of otombo malts having levels above the EU allowable limit. Fumonisin B₁ was quantified in both omalodu (84%) and otombo (42%) malts. Emerging mycotoxins, aflatoxin precursors, and ergot alkaloids were quantified in both malts. Notably, 102 metabolites were quantified in both malts, with 96% in omalodu malts and 93% in otombo malts. An average of 48 metabolites were quantified in otombo malts while an average of 67 metabolites were quantified in omalodu malts. The study accentuates the need to monitor mycotoxins in sorghum malts intended for brewing and to determine their fate in the beverages.

Development of an Impedimetric Aptasensor for Label Free Detection of Patulin in Apple Juice

In the present work, an aptasensing platform was developed for the detection of a carcinogenic mycotoxin termed patulin (PAT) using a label-free approach. The detection was mainly based on a specific interaction of an aptamer immobilized on carbon-based electrode. A long linear spacer of carboxy-amine polyethylene glycol chain (PEG) was chemically grafted on screen-printed carbon electrodes (SPCEs) via diazonium salt in the aptasensor design. The NH₂-modified aptamer was then attached covalently to carboxylic acid groups of previously immobilized bifunctional PEG to build a diblock macromolecule. The immobilized diblocked molecules resulted in the formation of long tunnels on a carbon interface, while the aptamer was assumed as the gate of these tunnels. Upon target analyte binding, the gates were assumed to be closed due to conformational changes in the structure of the aptamer, increasing the resistance to the charge transfer. This increase in resistance was measured by electrochemical impedance spectroscopy, the main analytical technique for the quantitative detection of PAT. Encouragingly, a good linear range between 1 and 25 ng was obtained. The limit of detection and limit of quantification was 2.8 ng L⁻¹ and 4.0 ng L⁻¹, respectively. Selectivity of the aptasensor was confirmed with mycotoxins commonly occurring in food. The developed apta-assay was also applied to a real sample, i.e., fresh apple juice spiked with PAT, and toxin recovery up to 99% was observed. The results obtained validated the suitability and selectivity of the developed apta-assay for the identification and quantification of PAT in real food samples.

Evaluation of interleukin-6 concentration in the liver of Albino Swiss mice after intoxication with various doses of patulin

Patulin is a mycotoxin produced by many species of the fungi. The toxic action of patulin mainly affects the gastrointestinal tract and the immune system. The aim of our work was to assess the toxic effect of patulin, based on the analysis of interleukin IL-6 concentrations in the liver of test animals loaded with different doses of this mycotoxin. The research was conducted on mice which were assigned to 6 groups receiving different doses of active substances. After decapitation, their livers were taken for laboratory testing.

Our studies have shown that chronic intoxication with patulin at 0.1 LD50 leads to a statistically significant increase in IL-6 concentration in the liver of the animals. We also found that the loading of experimental animals with a single dose of patulin in the amount of 0.5 LD50 and 0.2 LD50 also leads to a statistically significant increase in this interleukin in the examined organ. There was no difference in its concentration compared to the control group only after the single dose of the lowest concentration of patulin, while the highest average IL-6 concentration was recorded in the liver of animals loaded with the highest single dose of patulin. After applying, one-time doses of this mycotoxin in the amount of 0.2 LD50 and 0.1 LD50, the mean concentrations of IL-6 in the liver in animals from these groups were statistically significantly lower.

In conclusion, the analysis of the obtained results confirms the fact of the hepatotoxic effect of patulin.

Patulin removal from synbiotic apple juice using Lactobacillus plantarum ATCC 8014

AIMS

The aim of this study was to evaluate the elimination of patulin (PAT) by Lactobacillus plantarum ATCC 8014 from artificially contaminated apple juice and its dependence on prebiotic, citric acid and ascorbic acid content.

METHODS AND RESULTS

A central composite design was used for studying each of the three factors at five levels to find the optimum concentrations. The results showed that inserting 2·3% (w/v) fructooligosaccharide, 213 mg l^-1 ascorbic acid and 1·4 g l^-1 citric acid to apple juice with inoculating 3·6 × 10¹¹ CFU per ml, L. plantarum improved the efficiency of PAT removal to 95·91% during 6 weeks cold storage. SDS-PAGE of cell surface proteins of probiotics revealed that surface layer proteins have an important role in PAT removal from apple juice. No significant difference was observed in the flavour and colour of the optimized synbiotic apple juice and in the control sample until 3 weeks of cold storage.

CONCLUSION

Lactobacillus plantarum ATCC 8014 is capable of PAT removal from artificially contaminated synbiotic apple juice.

SIGNIFICANCE AND IMPACT OF THE STUDY

Synbiotic apple juice artificially contaminated with PAT will be safe for consumers after the first day of probiotic inoculation; and surface layer proteins of probiotic cells are responsible for PAT removal.

Advantageous Extraction, Cleanup, and UHPLC-MS/MS Detection of Patulin Mycotoxin in Dietary Supplements and Herbal Blends Containing Hawberry from Crataegus spp

Patulin (PAT) is a highly genotoxic mycotoxin still found as the common contaminant of various kinds of spoiled fruits and related commodities which are often endorsed as the health-enhancing products. Thus, a fast and convenient liquid-solid extraction followed by a solid-phase cleanup with the MycoSep®228 AflaPat multifunctional column was used for the highly efficient isolation of PAT with an average recovery of 112.7% from commercial dietary supplements and herbal blends formulated with dried hawberry. Analysis of the PAT content was carried out using gradient elution with a Synergi Polar C18 column (150 × 2 mm, 4 μm) and UHPLC system equipped with a mass spectrometer. PAT was detected in all (n=14) commercial single-component dietary supplements formulated with dried hawberry belonging to Crataegus monogyna and/or Crataegus laevigata. Similarly, PAT was detected in 67% of the studied multicomponent commercial herbal blends (n=6) that contained-in addition to hawberry-different amounts of apple, chokeberry, elderberry, hibiscus, or mallow. Moreover, the PAT content was determined in the hawberry collected from the mature wild hawthorn trees belonging to three botanical species, Crataegus monogyna Jacq., Crataegus laevigata (Poiret) DC, and Crataegus rhipidophylla Gand, growing in the recreational forest areas and in the law-protected state national forest park in Poland. In conclusion, to prevent PAT accumulation and reduce the health risk of consumers in globalizing markets, the implementation of improved cultivation/processing practices of hawthorn trees and hawberry as well as increased analytical control related to the presence of PAT in dietary supplements and herbal blends formulated with fresh, dried, or frozen hawberry should be urgently recommended.

Isotopic Labeling Studies Reveal the Patulin Detoxification Pathway by the Biocontrol Yeast Rhodotorula kratochvilovae LS11

Patulin (1) is a mycotoxin contaminant in fruit and vegetable products worldwide. Biocontrol agents, such as the yeast Rhodotorula kratochvilovae strain LS11, can reduce patulin (1) contamination in food. R. kratochvilovae LS11 converts patulin (1) into desoxypatulinic acid (DPA) (5), which is less cytotoxic than the mycotoxin (1) to in vitro human lymphocytes. In the present study, we report our investigations into the pathway of degradation of patulin (1) to DPA (5) by R. kratochvilovae. Isotopic labeling experiments revealed that 5 derives from patulin (1) through the hydrolysis of the γ-lactone ring and subsequent enzymatic modifications. The ability of patulin (1) and DPA (5) to cause genetic damage was also investigated by the cytokinesis-block micronucleus cytome assay on in vitro human lymphocytes. Patulin (1) was demonstrated to cause much higher chromosomal damage than DPA (5).

Investigation of patulin and citrinin in grape must and wine from grapes naturally contaminated by strains of Penicillium expansum

Twenty three strains of Penicillium expansum, as a predominant species, were isolated from 23 (92%) out of 25 grape samples of 17 different grape varieties. The results of the identification of P. expansum strains were confirmed by a PCR method. Most of the isolates of P. expansum (21/23, 91%), when tested for toxigenicity, were bi-toxigenic: they produced citrinin (CIT) and particularly high amounts of patulin (PAT). A validated UPLC-MS/MS method for the determination of PAT and CIT was applied. The limits of quantification (LOQ) for PAT and CIT in grape must and toxigenicity testing samples were 100 and 2 ng/g, respectively. The results of PAT and CIT quantification in 23 grape must samples demonstrated the occurrence of PAT in 10 (43%) grape must samples (mean: 171 ng/g; median: 50 ng/g; and range: 143-644 ng/g) and the occurrence of CIT in two (9%) grape must samples (mean: 1 ng/g; median: 1 ng/g; and range: 2.5-3.5 ng/g). This is the first report on the natural occurrence of CIT in grape must. A validated HPLC-UV-VIS method for the determination of PAT in wine samples was applied, and concentrations in all 23 wine samples were below the LOQ (<10 ng/g).

Glutathione Reduction of Patulin-Evoked Cytotoxicity in HEK293 Cells by the Prevention of Oxidative Damage and the Mitochondrial Apoptotic Pathway

Patulin (PAT) is a mycotoxin frequently detected in moldy fruits and fruit products. This study investigated the protective role of glutathione (GSH), an antioxidant agent, against PAT-induced cytotoxicity and its potential mechanisms in HEK293 cells. The obtained results showed that the addition of GSH significantly increased cell viability and decreased apoptosis induced by PAT. Additionally, GSH decreased intracellular ROS and mitochondrial ROS overproduction, suppressed the decline of the mitochondrial membrane potential, and maintained cellular ATP contents. GSH prevented the impairment of mitochondrial oxidative-phosphorylation system and, especially, enhanced the mRNA and protein levels of electron-transport-chain complex III (UQCRC2) and complex V (ATP5, ATP6 and ATP8). Furthermore, GSH increased endogenous GSH contents; enhanced the antioxidant-enzyme activities of SOD, CAT, GR, and GPx; and modulated oxidative damage. These results suggest that GSH reduces PAT-induced cytotoxicity via inhibition of oxidative damage and the mitochondrial apoptotic pathway in HEK293 cells.

Identification of differentially expressed genes involved in spore germination of Penicillium expansum by comparative transcriptome and proteome approaches

In this study, Penicillium expansum, a common destructive phytopathogen and patulin producer was isolated from naturally infected apple fruits and identified by morphological observation and rDNA-internal transcribed spacer analysis. Subsequently, a global view of the transcriptome and proteome alteration of P. expansum spores during germination was evaluated by RNA-seq (RNA sequencing) and iTRAQ (isobaric tags for relative and absolute quantitation) approaches. A total of 3,026 differentially expressed genes (DEGs), 77 differentially expressed predicted transcription factors and 489 differentially expressed proteins (DEPs) were identified. The next step involved screening out 130 overlapped candidates through correlation analysis between the RNA-seq and iTRAQ datasets. Part of them showed a different expression trend in the mRNA and protein levels, and most of them were involved in metabolism and genetic information processing. These results not only highlighted a set of genes and proteins that were important in deciphering the molecular processes of P. expansum germination but also laid the foundation to develop effective control methods and adequate environmental conditions.

Biocontrol Agents Increase the Specific Rate of Patulin Production by Penicillium expansum but Decrease the Disease and Total Patulin Contamination of Apples

Synthetic fungicides are commonly employed for the control of postharvest diseases of fruits. However, due to health concerns about the use of these chemicals, alternative control methods including biocontrol based on antagonistic yeasts are gaining in popularity. In this study, we investigated the effects of two biocontrol yeasts, Rhodotorula mucilaginosa strain 3617 and Rhodotorula kratochvilovae strain LS11, on blue mold and patulin (PAT) contamination caused by Penicillium expansum strains PY and FS7 in artificially inoculated Fuji apples stored at 20°C for 9 days. To correlate the development of the P. expansum strains in yeast-treated and untreated apples with PAT production, we quantified their biomass in the infected fruits using a recently published quantitative real-time polymerase chain reaction method based on specific primers for patF, a gene from P. expansum that is involved in PAT biosynthesis. Both yeasts significantly reduced the disease incidence caused by the two strains of P. expansum up to 5–7 days of incubation, and lowered their biomass and the progression of symptoms up to 9 days. Interestingly, both yeasts strains increased the rate of PAT production (expressed as ng patulin/μg fungal DNA) by the two pathogenic strains. Nevertheless, both biocontrol agents reduced the total PAT contamination, especially in the case of P. expansum strain FS7, the higher PAT producer of the two tested P. expansum strains. Comparing between the yeast strains, R. kratochvilovae LS11 was more effective than R. mucilaginosa 3617 for the control of P. expansum.

Patulin Degradation by the Biocontrol Yeast Sporobolomyces sp. Is an Inducible Process

Patulin is a mycotoxin produced by Penicillium expansum and a common contaminant of pome fruits and their derived products worldwide. It is considered to be mutagenic, genotoxic, immunotoxic, teratogenic and cytotoxic, and the development of strategies to reduce this contamination is an active field of research. We previously reported that Sporobolomyces sp. is able to degrade patulin and convert it into the breakdown products desoxypatulinic acid and ascladiol, both of which were found to be less toxic than patulin. The specific aim of this study was the evaluation of the triggering of the mechanisms involved in patulin resistance and degradation by Sporobolomyces sp. Cells pre-incubated in the presence of a low patulin concentration showed a higher resistance to patulin toxicity and a faster kinetics of degradation. Similarly, patulin degradation was faster when crude intracellular protein extracts of Sporobolomyces sp. were prepared from cells pre-treated with the mycotoxin, indicating the induction of the mechanisms involved in the resistance and degradation of the mycotoxin by Sporobolomyces sp. This study contributes to the understanding of the mechanisms of patulin resistance and degradation by Sporobolomyces sp., which is an essential prerequisite for developing an industrial approach aiming at the production of patulin-free products.

The response of growth and patulin production of postharvest pathogen Penicillium expansum to exogenous potassium phosphite treatment

In this study, the effects of exogenous potassium phosphite (Phi) on growth and patulin production of postharvest pathogen Penicillium expansum were assessed. The results indicated that P. expansum under 5mmol/L Phi stress presented obvious development retardation, yield reduction of patulin and lower infectivity to apple fruit. Meanwhile, expression analysis of 15 genes related to patulin biosynthesis suggested that Phi mainly affected the early steps of patulin synthetic route at transcriptional level. Furthermore, a global view of proteome and transcriptome alteration of P. expansum spores during 6h of Phi stress was evaluated by iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq (RNA sequencing) approaches. A total of 582 differentially expressed proteins (DEPs) and 177 differentially expressed genes (DEGs) were acquired, most of which participated in carbohydrate metabolism, amino acid metabolism, lipid metabolism, genetic information processing and biosynthesis of secondary metabolites. Finally, 39 overlapped candidates were screened out through correlational analysis between iTRAQ and RNA-seq datasets. These findings will afford more precise and directional clues to explore the inhibitory mechanism of Phi on growth and patulin biosynthesis of P. expansum, and be beneficial to develop effective controlling approaches based on Phi.

Effects of patulin and ascladiol on porcine intestinal mucosa: An ex vivo approach

Patulin (PAT) is a secondary metabolite mainly produced by Aspergillus and Penicillium that is frequently found contaminating apples and rotten fruits. Patulin can be transformed in potencially less toxic compounds such as ascladiol (ASC). Toxic effects of patulin were described in rats and in in vitro models, however concerning ascladiol, data are restricted to metabolic pathways. The aim of the present study was to evaluate the effects of different concentrations of PAT (10 μM, 30 μM, 100 μM) and ASC (30 μM, 100 μM) on intestinal tissue using the jejunal explant model. Explants from pigs were exposed for 4 h to PAT and ASC and after this period were processed for histological, morphometrical and immunohistochemical analysis. Mild histological changes were observed in jejunal explants exposed to PAT and ASC, however no significant difference in the lesional score or villi height was observed between the PAT/ASC-groups and the control. Also, explants exposed to 100 μM of PAT showed a significant decrease in goblet cells density and a significant increase in cell apoptosis. These results indicate that high levels of patulin can induce mild toxic effects on intestinal mucosa whereas ascladiol apparently is non-toxic to intestinal tissue.