Antagonistic Effect of Selenium on Fumonisin B1 Promotes Neutrophil Extracellular Traps Formation in Chicken Neutrophils

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.

Importance of Selenoprotein O in Regulating Hmgb1: A New Direction for Modulating ROS-Dependent NETs Formation to Aggravate the Progression of Acute Liver Inflammation

Selenoproteins (Sels) are a class of essential biomolecules that play critical roles in cellular homeostasis. SelO was identified as the preferential source of selenium in the liver, implying its potential as a key regulatory factor in hepatic pathophysiology. Bioinformatics analysis of data from GEO data sets revealed marked downregulation of SelO in liver injury. However, its function and regulatory mechanisms in the liver remain unclear. To address this, we investigated the effect of SelO ablation on acute liver inflammation, focusing on its association with inflammation and neutrophil extracellular traps (NETs) formation. Wild-type (WT) and SelO-knockout mice were used to establish a lipopolysaccharide (LPS) exposure model and a coculture model (AML12 cells and neutrophils) in vitro. Our findings revealed that LPS stimulation significantly reduced SelO expression in the WT mouse liver. SelO deletion promoted the expression of Hmgb1 and marker cytokines for chemokines, NETs generation, pyroptosis and inflammation, and induced an imbalance in redox homeostasis. Immunofluorescence, SYTOX staining, and scanning electron microscopy confirmed that SelO silencing promoted reactive oxygen species (ROS)-dependent NETs formation. Moreover, the coculture model demonstrated that excessive NETs formation exacerbated SelO-ablation-induced hepatic inflammation. Importantly, we confirmed the significant involvement of the Hmgb1/ROS axis in the development of acute liver inflammation in the absence of SelO. Our results demonstrated that SelO ablation promoted neutrophil recruitment and enhanced ROS-dependent NETs formation by increasing Hmgb1 expression levels, thereby aggravating LPS-induced pyroptosis and inflammation. This study not only uncovered the crucial biological functions of SelO, but also shed light on its regulatory implications in the inflammatory process.

Fumonisin B1 Exerts Immunosuppressive Effects Through Cytoskeleton Remodeling and Function Attenuation of Mature Dendritic Cells

Fumonisin B1 (FB1) is one of the most toxic mycotoxins and is harmful to humans and animals due to its hepatotoxicity, immunotoxicity and carcinogenicity. However, the mechanism of its immunosuppressive effect is still under investigation. Dendritic cells (DCs) are the most potent professional antigen-presenting cells, and their differentiation, maturation and immunomodulatory functions are closely related to the immunotoxicity of certain mycotoxins. Migratory capacity is a prerequisite for mature DCs (mDCs) to move and present antigens in secondary lymphoid tissue, whereas the mechanical properties and cytoskeletal structure are critical for their migration and immune functions. Therefore, the effects of FB1 on the cell viability, mechanical characteristics, cytoskeletal structure and its binding proteins, migration, co-stimulatory molecules and the immune functions of mDCs were investigated to explore the potential mechanisms of immunotoxicity. The results showed that FB1 could impair the chemotactic migratory capability, the expression of co-stimulatory molecules and the ability of DCs to stimulate T cell proliferation. Further analyses elucidated that the mechanical properties of mDCs were changed, the cytoskeletal structures were reorganized and the expressions of cytoskeleton-binding proteins were regulated. In conclusion, the attenuated migration and immune functions of mDCs caused by FB1 may be related to their altered mechanical properties and cytoskeleton remodeling, which may be one of the action modes for FB1 to exert its immunosuppressive effect.

Selenium deficiency modulates necroptosis-mediated intestinal inflammation in broiler through the lncRNAWSF27/miRNA1696/GPX3 axis

Deficiency of selenium (Se), an important trace element, causes diarrhea and even death in broilers, thereby affecting the economic development of poultry production. Adding Se is one way to relieve this situation; however, it has not fundamentally resolved intestinal inflammation. Therefore, we sought a new strategy to alleviate intestinal inflammation by studying the specific mechanisms of Se deficiency. By replicating the Se-deficient broiler model and establishing a chicken small intestinal epithelial cell (CSIEC) model, we determined that Se deficiency caused intestinal oxidative stress and necroptotic intestinal inflammation in broilers by decreasing glutathione peroxidase (GPX) 3 expression. Simultaneously, the expression of long non-coding RNA (lncRNA)WSF27 decreased and that of miR-1696 increased in Se-deficient intestines. Recently discovered competing endogenous RNAs (ceRNAs) form novel regulatory networks, which were found that selenoproteins are involved in ceRNA regulation. However, the mechanism of action of the non-coding RNA/GPX3 axis in Se-deficient broiler intestinal inflammation remains unclear. This study aimed to explore the mechanism through which Se deficiency regulates intestinal inflammation in broilers through the lncRNAWSF27/miR-1696/GPX3 axis. Our previous studies showed that lncRNAWSF27, miR-1696, and GPX3 have ceRNA-regulatory relationships. To further determine the role of the lncRNAWSF27/miR-1696/GPX3 axis in Se-deficient broiler intestinal inflammation, CSIEC models with GPX3 knockdown/overexpression, lncRNAWSF27 knockdown, or miR-1696 knockdown/overexpression were established to simulate intestinal injury. GPX3 knockdown, as well as lncRNAWSF27 and miR-1696 overexpression, aggravated cell damage. On the contrary, it can alleviate this situation. Our results reveal that the mechanism of lncRNAWSF27/miR-1696/GPX3 regulated Se-deficient broiler intestinal inflammation. This conclusion enriches our understanding of the mechanism of intestinal injury caused by Se deficiency and contributes to the diagnosis of Se-deficient intestinal inflammation and relevant drug development.

Selenium Ameliorates Aluminum Poisoning-Induced Impaired Production of Neutrophil Extracellular Traps in Chicken

Neutrophil extracellular traps (NETs) are released by neutrophils to modulate the immune response. Aluminum (Al) poisoning is linked to immunotoxicity, and selenium (Se) can maintain immune homeostasis. In this study, we investigated the toxic effects of Al on the release of NETs, the antagonistic effect of Se on Al-induced toxicity, and the potential molecular mechanisms underlying these processes. We assessed the cytotoxicity of aluminum on neutrophils using CCK-8 assay, visualized the structure of selenium/aluminum-induced NETs through immunofluorescence and scanning electron microscope, quantified ROS release during NETs formation using fluorescence microplate analysis, and employed the selenoprotein levels to dissect the mechanisms underlying selenium and aluminum-induced NETs release. Peripheral blood neutrophils were exposed to zymosan for a duration of 3 h to induce the formation of NETs. Microscopic analysis indicated that NETs formation was inhibited in the presence of aluminum. Furthermore, assessments using a multifunctional microplate reader demonstrated that aluminum suppressed both the production of extracellular DNA and the reactive oxygen species burst in neutrophils. Western blot analysis revealed that aluminum altered the levels of cellular selenoproteins. In contrast, Se reduced the Al-induced toxic reaction including restored NETs production, ROS burst, and selenoprotein levels. These results indicate that Al decreases the formation of NETs induced by Zym, while Se inhibits the Al toxicity, promoting the formation of NETs by modulating the expression of selenoprotein.

Selenium-rich yeast counteracts the inhibitory effect of nanoaluminum on the formation of porcine neutrophil extracellular traps

Aluminum is widely used in daily life due to its excellent properties. However, aluminum exposure to the environment severely threatens animal and human health. Conversely, selenium (Se) contributes to maintaining the balance of the immune system. Neutrophils exert immune actions in several ways, including neutrophil extracellular traps (NETs) that localize and capture exogenous substances. Despite the recent investigations on the toxic effects of aluminum and its molecular mechanisms, the immunotoxicity of aluminum nanoparticles on pigs and the antagonistic effect of selenium on aluminum toxicity are poorly understood. Here, we treated porcine peripheral blood neutrophils with zymosan for 3 h to induce NETs formation. Then, we investigated the effect of nanoaluminum on NETs formation in pigs and its possible molecular mechanisms. Microscopy observations revealed that NETs formation was inhibited by nanoaluminum. Using a multifunctional microplate reader, the production of extracellular DNA and the burst of reactive oxygen species (ROS) in porcine neutrophils were inhibited by nanoaluminum. Western blot analyses showed that nanoaluminum caused changes in amounts of cellular selenoproteins. After Se supplementation, the production of porcine NETs, the burst of ROS, and selenoprotein levels were restored. This study indicated that nanoaluminum inhibited the zymosan-induced burst of ROS and release of NETs from porcine neutrophils, possibly through the selenoprotein signaling pathway. In contrast, Se supplementation reduced the toxic effects of nanoaluminum and restored NETs formation.

Selenomethionine attenuates ochratoxin A-induced small intestinal injury in rabbits by activating the Nrf2 pathway and inhibiting NF-κB activation

The aim of this study was to investigate whether selenomethionine (SeMet) could attenuate intestinal injury in rabbits induced by ochratoxin A (OTA). Sixty 35-day-old IRA rabbits with similar weights were randomly assigned to the control group, OTA group (0.2 mg OTA/kg b.w), OTA+ 0.2 mg/kg Se (0.2 mg OTA/kg b.w + 0.2 mg SeMet/kg feed), OTA+ 0.4 mg/kg Se (0.2 mg OTA/kg b.w + 0.4 mg SeMet/kg feed) and OTA+ 0.6 mg/kg Se (0.2 mg OTA/kg b.w + 0.6 mg SeMet/kg feed). The rabbits were examined after oral administration of different doses of SeMet for 21 days and were intragastrically administered OTA for 7 consecutive days. The results showed that pretreatment with different doses of SeMet protected against the changes in serum biochemical indicators and the decline in production performance caused by OTA exposure. In addition, the activities of SOD, GSH-PX and T-AOC were significantly increased, and the levels of MDA and ROS were decreased after SeMet pretreatment; thus, oxidative damage in rabbit jejunum tissue due to OTA exposure was inhibited. SeMet stimulates Nrf2 and inhibits the NF-κB signalling pathway; the anti-inflammatory response and antioxidative stress in rabbits were improved, and the intestinal barrier damage caused by OTA exposure was improved. In summary, SeMet alleviates OTA-induced intestinal toxicity in rabbits by activating the Nrf2 pathway and inhibiting NF-κB activation. Moreover, 0.4 mg/kg SeMet induced the most significant improvement.

The emerging role of neutrophil extracellular traps in endometritis

Endometritis is a kind of common obstetric disease in women, usually caused by various pathogenic bacteria. Neutrophil infiltration is one of the most important pathological features of endometritis. Neutrophils can reach the uterine cavity through the endometrium, and make early response to the infection caused by the pathogen. Neutrophil extracellular traps (NETs), a meshwork of chromatin fibers extruded by neutrophils, have a role in entrapping microbial pathogens. It has been confirmed that NETs have a strong antibacterial effect and play crucial roles in the occurrence and development of various diseases. However, while killing pathogenic bacteria, excessive NETs formation may cause immune damage to the body. NETs are present in endometrium of female domestic animals in different physiological periods, especially post-mating, postpartum and in the presence of lesions, especially in endometritis. Meanwhile, NETs and its products might contribute to a reduction in physical clearance and persistent endometritis. In brief, NETs is a double-edged sword and it may play a different role in the development of endometritis, which may be beneficial or harmful, and its specific mechanism needs further study. Here we provide an overview of the role of NETs in the development of endometritis and the regulatory role of selenium on NETs formation and endometritis.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Selenium Improves Bone Microenvironment-Related Hematopoiesis and Immunity in T-2 Toxin-Exposed Mice

The T-2 toxin is one of the most frequent contaminants in the environment and agricultural production globally. It exerts a wide range of toxic effects. Selenium (Se), as an antioxidant, has the potential to be widely used to antagonize mycotoxin toxicity. To investigate the protective effects of Se on bone microenvironment (BM)-related hematopoiesis and immunity after T-2 toxin exposure, 36 male mice were treated with the T-2 toxin (1 mg/kg) and/or Se (0.2 mg/kg) by intragastric administration for 28 days. The results showed that Se alleviated T-2 toxin-induced cytopenia and splenic extramedullary hematopoiesis. Se also significantly relieved T-2 toxin-induced immunosuppression, as assessed by immune factors and lymphocytes. Furthermore, Se also attenuated oxidative stress and apoptosis and improved the BM in T-2 toxin-exposed mice. Therefore, Se improves BM-related hematopoiesis and immunity after T-2 toxin exposure. This study provides references for identifying the toxic mechanism and screening potential therapeutic drugs of the T-2 toxin.

Promising instrument-free detections of various analytes using smartphones with Spotxel® Reader

In consideration of the problems related to food safety, environmental pollution, and the spread of infected diseases nowadays, we urgently need testing methods that can be easily performed by common people. Smartphone-based detections are promising for general applications. However, some of these analytical strategies require a combination of accessories and instruments, such as portable electrochemical workstations, mini multi-mode microplate readers, and complex temperature control devices, etc., which are small but still expensive. Herein, we comprehensively introduce a free app (Spotxel^® Reader) that can provide accurate data analysis for microplate or parallel-format test sensors without an instrument. By simulating the optical signal of the test samples through a smartphone, the sensing results can be obtained for free. We discuss the detection strategies involved in the reported smartphone-based analyses using Spotxel^® Reader. Prospects for the development of this free app for future detection applications are presented. This review aims to popularize free analysis software, so that ordinary people may realize convenient tests.

Modulation of the Functional State of Mouse Neutrophils by Selenium Nanoparticles In Vivo

This study aimed to discover the immunomodulatory effect of selenium nanoparticles (SeNPs) on the functional state of neutrophils in vivo. Intraperitoneal injections of SeNPs (size 100 nm) 2.5 mg/kg/daily to BALB/c mice for a duration of 7-28 days led to the development of an inflammatory reaction, which was registered by a significant increase in the number of neutrophils released from the peritoneal cavity, as well as their activated state, without additional effects. At the same time, subcutaneous injections of the same SeNPs preparations at concentrations of 0.1, 0.5, and 2.5 mg/kg, on the contrary, modulated the functional state of neutrophils depending on the concentration and duration of SeNPs administration. With the use of fluorescence spectroscopy, chemiluminescence, biochemical methods, and PCR analysis, it was found that subcutaneous administration of SeNPs (0.1, 0.5, and 2.5 mg/kg) to mice for a short period of time (7-14 days) leads to modification of important neutrophil functions (adhesion, the number of migrating cells into the peritoneal cell cavity, ROS production, and NET formation). The obtained results indicated the immunostimulatory and antioxidant effects of SeNPs in vivo during short-term administration, while the most pronounced immunomodulatory effects of SeNPs were observed with the introduction of a low concentration of SeNPs (0.1 mg/kg). Increase in the administration time of SeNPs (0.1 mg/kg or 2.5 mg/kg) up to 28 days led to a decrease in the adhesive abilities of neutrophils and suppression of the expression of mRNA of adhesive molecules, as well as proteins involved in the generation of ROS, with the exception of NOX2; there was a tendency to suppress gene expression pro-inflammatory factors, which indicates the possible manifestation of immunosuppressive and anti-inflammatory effects of SeNPs during their long-term administration. Changes in the expression of selenoproteins also had features depending on the concentration and duration of the administered SeNPs. Selenoprotein P, selenoprotein M, selenoprotein S, selenoprotein K, and selenoprotein T were the most sensitive to the introduction of SeNPs into the mouse organism, which indicates their participation in maintaining the functional status of neutrophils, and possibly mediated the immunomodulatory effect of SeNPs.

Occurrence, transformation, and toxicity of fumonisins and their covert products during food processing

Fumonisins comprise structurally related metabolites mainly produced by Fusarium verticillioides and Fusarium proliferatum. Contamination with fumonisins causes incalculable damage to the economy and poses a great risk to animal and human health. Fumonisins and their covert products are found in cereals and cereal products. Food processing significantly affects the degradation of toxins and the formation of covert toxins. However, studies on fumonisins and their covert mycotoxins remain inadequate. This review aims to summarize changes in fumonisins and the generation of covert fumonisins during processing. It also investigates the toxicity and determination methods of fumonisins and covert fumonisins, and elucidates the factors affecting fumonisins and their covert forms during processing. In addition to the metabolic production by plants and fungi, covert fumonisins are mainly produced by covalent or noncovalent binding, complexation, or physical entrapment of fumonisins with other substances. The toxicity of covert fumonisins is similar to that of free fumonisins and is a non-negligible hazard. Covert fumonisins are commonly found in food matrices, and methods to analyze them have yet to be improved. Food processing significantly affects the conversion of fumonisins to their covert toxins.