Effects of FB1 and HFB1 on Autonomous Exploratory and Spatial Memory and Learning Abilities in Mice

Neurocognitive impairments induced by cyclopiazonic acid exposure in mice: Effects on learning and memory

Cyclopiazonic acid (CPA), an emerging mycotoxin, has been detected in various foods and feeds. CPA is believed to induce depressive symptoms, but its potential toxic effects on the neurobehavior of organisms remain unclear. In this study, the behavioral effects of 5 mg/kg CPA exposure in C57BL/6 J male mice were evaluated using the open field test, novel object recognition, and the Morris water maze test. Additionally, the underlying mechanisms were investigated by measuring CPA and neurotransmitter levels in the hippocampus, along with metabolomic analysis. The results showed that CPA exposure, which can cross the blood-brain barrier, caused learning and memory dysfunction in mice, accompanied by mild structural damage to the brain and disruption of neurotransmitter homeostasis. The relative levels of GABA and 5-HIAA significantly decreased, while the relative levels of Glu, DA, ACH, and NE were markedly elevated. Untargeted metabolomics analysis revealed that CPA significantly downregulated the levels of arginine while markedly upregulating the levels of glutathione, AMP, and (S)-malate. Furthermore, correlation analysis indicated significant positive and negative correlations between hippocampal metabolites and neurotransmitter changes as well as behavioral markers. These findings provide novel insights into CPA-induced neurotoxicity and offer valuable data for assessing the toxicity of emerging toxins.

Fumonisin B1 neurotoxicity: Preclinical evidence, biochemical mechanisms and therapeutic strategies

The neurotoxic effects of fungal toxins in both humans and animals have been well documented. Fumonisin B1 (FB1), a mycotoxin produced by fungi of the Fusarium species, is the most toxic fumonisin variant whose neurotoxic effect is still being elucidated. This review highlights the biochemical aspects of FB1 neurotoxicity, such as its mechanisms of action as well as therapeutic strategies. Both in vitro and in vivo studies have demonstrated that alteration in sphingolipid metabolism is a major event in FB-induced neurotoxicity. Studies have also shown that neurotoxicity due to FB1 involves dysregulation of several biochemical events in the brain, such as induction of oxidative stress and inflammation, mitochondrial dysfunction and associated programmed cell death, inhibition of acetylcholinesterase and alteration of neurotransmitter levels, decreased activity of Na+K+ ATPase, as well as disruption of blood-brain barrier. This review highlights the potential public health effects of FB1-induced neurotoxicity and the need to limit human and animal exposure to FB1in order to prevent its neurotoxic effect. Moreover, it is hoped that this review would stimulate studies aimed at filling the current research gaps such as delineating the effect of FB1 on the blood-brain barrier and appropriate therapies for neurotoxicity caused by FB1.

Magnolol protects C6 glioma cells against neurotoxicity of FB1 via modulating PI3K/Akt and mitochondria-associated apoptosis signaling pathways

Fumonisin B1 (FB1) is a contaminant commonly occurring in crops and food. Mycotoxin contamination, including FB1, has been progressively shown to be an important risk factor in mediating neurotoxicity and neurodegenerative diseases. Studies have found that magnolol (MAG) exhibits favorable pharmacological effects in the central nervous system. However, the protective effects of MAG against FB1-induced neurotoxicity and the molecular pathways involved have not been fully elucidated. Our study aimed to investigate the neuroprotective effects of MAG on FB1-exposed C6 cells and to identify the underlying mechanisms. A model of FB1-induced cytotoxicity in C6 glial cells was established. C6 cells were treated with MAG (40, 80 and 160 μM) in the presence/absence of FB1 (15 μM) and then assessed for cell viability, cellular and mitochondrial morphology and oxidative stress. The mechanism of action of MAG was revealed using a variety of means including RNA-seq, qRT-PCR, Western blot, immunofluorescence, scanning electron microscopy analysis and agonist validation experiments. Our results indicated that MAG significantly alleviated AFB1-induced C6 astroglial cytotoxicity, as evidenced by elevated cell viability and restoration of overall cellular and mitochondrial morphology. Meanwhile, MAG also alleviated oxidative stress in FB1-exposed C6 cells, with 80 μM MAG showing the best effect. Transcriptome analysis showed that PI3K/Akt and apoptosis involved in it might be the key pathway for MAG to treat FB1 neurotoxicity. MAG suppressed FB1-induced mitochondria-dependent apoptosis in C6 cells, primarily manifested by reduced apoptosis rate and reversal of apoptosis-associated protein expression. It was verified that MAG restored the expression of p-PI3K and p-Akt in FB1-treated cells and reversed the downstream effectors IKKα and NF-κB via measurement of related protein levels. The rescue experiment using Akt pathway activator (SC79) was further confirmed that activation of the PI3K/Akt signaling pathway is an effective strategy for MAG to mitigate FB1-induced cytotoxicity in C6 astroglial cells.

Effect of Fumonisin B1 and Hydrolyzed FB1 Exposure on Intestinal and Hepatic Toxicity in BALB/c Mice

Fumonisins, a class of mycotoxins, pose significant health risks due to widespread contamination. The presence of masked mycotoxins complicates risk assessments because of insufficient regulation and potential toxicity as well as in vivo transformation. This study aims to compare the toxic effects of continuous exposure to fumonisin B1 (FB1) and hydrolyzed FB1 (HFB1) on the gut-liver axis in mice. After 21 d of exposure to FB1 and HFB1, the distributions of FB1 and its metabolites in mice were analyzed, and their effects on intestinal morphology, gut microbial diversity, short-chain fatty acids (SCFAs), inflammatory factors, and hippocampal metabolites were assessed. The results revealed that the highest concentrations of FB1 (61.87%) and HFB1 (53.56%) were detected in the cecum, followed by the colon. Exposure to FB1 and HFB1 resulted in compromised intestinal integrity, villi atrophy, elevated levels of inflammatory factors, and decreased total SCFAs. Both FB1 and HFB1 led to a significant reduction in the Firmicutes to Bacteroides ratio. Blood biochemical analysis and liver metabolomics indicated that FB1 and HFB1 also induced disturbances in the liver homeostasis. The complex correlations observed between the metabolomic and microbiota results underscore the involvement of the gut-liver axis in the disruption induced by these two mycotoxins. These findings highlight the systemic effects of FB1 and HFB1 on liver and gut health, providing valuable insights for further research into their mechanisms and health implications.

Bi2S3/BiOCl heterojunction-based photoelectrochemical aptasensor for ultrasensitive assay of fumonisin B1 via signal amplification with in situ grown Ag2S quantum dots

Fumonisin B1 (FB1) is a mycotoxin mainly found in corn, peanuts, and wheat crops, which affects human health. Based on bismuth sulfide/bismuth oxychloride (Bi2S3/BiOCl) composite material, silver sulfide (Ag2S) was grown in situ as a quantum dot sensitization signal, and a photoelectrochemical (PEC) aptasensor was designed by layer upon layer modification to detect FB1. Bi2S3/BiOCl has a wide range of visible light absorption, stable chemical properties, and a simple synthesis method. In the construction process, L-ascorbic acid (AA) is selected to provide electrons and inhibit photogenerated electron-hole (e-/h+) recombination. Under the optimal experimental conditions, the detection range of the fabricated PEC aptasensor was 0.001 ~ 100 ng/mL, and the detection limit was 0.016 pg/mL. The prepared PEC aptasensor has high sensitivity, stability, and reproducibility. The combination of aptamer and PEC sensor provides a novel method for the application of PEC sensor in mycotoxin detection.

Metabolic transformation of cyclopiazonic acid in liver microsomes from different species based on UPLC-Q/TOF-MS

To investigate the metabolic transformation of cyclopiazonic acid (CPA) in the liver of different species and to supplement accurate risk assessment information, the metabolism of CPA in liver microsomes from four animals and humans was studied using the ultra-high-performance liquid chromatography-quadrupole/time-of-flight method. The results showed that a total of four metabolites were obtained, and dehydrogenation, hydroxylation, methylation, and glucuronidation were identified as the main metabolic pathways of CPA. Rat liver microsomes exhibited the highest metabolic capacity for CPA, with dehydrogenated (C20H18N2O3) and glucuronic acid-conjugated (C26H28N2O10) metabolites identified in all liver microsomes except chicken, indicating significant species metabolic differences. Moreover, C20H18N2O3 was only detected in the incubation system with cytochromes P450 3A4 (CYP3A4). The hydroxylated (C20H20N2O4) and methylated (C21H22N2O3) metabolites were detected in all incubation systems except for the CYP2C9, with CYP3A4 demonstrating the strongest metabolic capacity. The "cocktail" probe drug method showed that CPA exhibited a moderate inhibitory effect on the CYP3A4 (IC50 value = 8.658 μM), indicating that the substrate had a negative effect on enzyme activity. Our results provide new insights to understand the biotransformation profile of CPA in animals and humans.

Mild endoplasmic reticulum stress alleviates FB1-triggered intestinal pyroptosis via the Sec62-PERK pathway

Fumonisin B1 (FB1), a water-soluble mycotoxin released by Fusarium moniliforme Sheld, is widely present in corn and its derivative products, and seriously endangers human life and health. Recent studies have reported that FB1 can lead to pyroptosis, however, the mechanisms by which FB1-induced pyroptosis remain indistinct. In the present study, we aim to investigate the mechanisms of pyroptosis in intestinal porcine epithelial cells (IPEC-J2) and the relationship between FB1-induced endoplasmic reticulum stress (ERS) and pyroptosis. Our experimental results showed that the pyroptosis protein indicators in IPEC-J2 were significantly increased after exposure to FB1. The ERS markers, including glucose-regulated Protein 78 (GRP78), PKR-like ER kinase protein (PERK), and preprotein translocation factor (Sec62) were also significantly increased. Using small interfering RNA silencing of PERK or Sec62, the results demonstrated that upregulation of Sec62 activates the PERK pathway, and activation of the PERK signaling pathway is upstream of FB1-induced pyroptosis. After using the ERS inhibitor 4-PBA reduced the FB1-triggered intestinal injury by the Sec62-PERK pathway. In conclusion, we found that FB1 induced pyroptosis by upregulating Sec62 to activate the PERK pathway, and mild ERS alleviates FB1-triggered damage. It all boils down to one fact, the study provides a new perspective for further, and improving the toxicological mechanism of FB1.

HIF-1α is a "brake" in JNK-mediated activation of amyloid protein precursor and hyperphosphorylation of tau induced by T-2 toxin in BV2 cells

Mycotoxins have been shown to activate multiple mechanisms that may potentially lead to the progression of Alzheimer's disease (AD). Overexpression/aberrant cleavage of amyloid precursor protein (APP) and hyperphosphorylation of tau (P-tau) is hallmark pathologies of AD. Recent advances suggest that the neurotoxic effects of mycotoxins involve c-Jun N-terminal kinase (JNK) and hypoxia-inducible factor-1α (HIF-1α) signaling, which are closely linked to the pathogenesis of AD. Due to the high toxicity and broad contamination of T-2 toxin, we assessed how T-2 toxin exposure alters APP and P-tau formation in BV2 cells and determined the underlying roles of HIF-1α and JNK signaling. The findings revealed that T-2 toxin stimulated the expression of HIF-1α and hypoxic stress factors in addition to increasing the expression of APP and P-tau. Additionally, HIF-1α acted as a "brake" on the induction of APP and P-tau expression by negatively regulating these proteins. Notably, T-2 toxin activated JNK signaling, which broke this "brake" to promote the formation of APP and P-tau. Furthermore, the cytoskeleton was an essential target for T-2 toxin to exert cytotoxicity, and JNK/HIF-1α participated in this damage. Collectively, when the T-2 toxin induces the production of APP and P-tau, JNK might interfere with HIF-1α's protective function. This study will provide clues for further research on the neurotoxicity of mycotoxins.