Immune modulatory effects of the foodborne contaminant citrinin in mice

Polysaccharides extracted from Polygonatum sibiricum alleviate intestine-liver-kidney axis injury induced by citrinin and alcohol co-exposure in mice

Citrinin (Cit) is a metabolite of Monascus Aspergillus that is known to be nephrotoxic and affects the safety of Monascus products. Here, we investigated the effects of an intervention with bioactive Polygonatum sibiricum polysaccharides (PSPS) on Cit-induced toxic damage in populations with dietary patterns characterized by alcohol consumption. Our results showed that the PSPS intervention significantly increased the levels of intestinal Cit and its metabolite M1. Additionally, the PSPS intervention mitigated intestinal damage, as well as liver and kidney stress, and flora disruption induced by combined exposure to Cit and alcohol. It also promoted the recovery of Lactobacillus abundance. However, there was no significant improvement in hippocampal damage. Metabolomics analysis indicated that the PSPS significantly influenced the metabolic pathways involved in energy metabolism in liver and kidney, such as aspartic acid and tyrosine metabolism. Correlation analysis revealed a significant relationship between the reduction of Cit metabolites and the differential metabolites in the liver and kidney. Our results demonstrated that the PSPS intervention showed promise in improving intestinal flora imbalances, enhancing the barrier function against Cit, alleviating intestinal, liver, and kidney damage, and addressing the metabolic disorders along the gut-liver-kidney axis resulting from the co-exposure to Cit and alcohol.

Apoptosis mediated by crosstalk between mitochondria and endoplasmic reticulum: A possible cause of citrinin disruption of the intestinal barrier

Citrinin (CTN) is a mycotoxin commonly found in contaminated foods and feed, posing health risks to both humans and animals. However, the mechanism by which CTN damages the intestine remains unclear. In this study, a model of intestinal injury was induced by administering 1.25 mg/kg and 5 mg/kg of CTN via gavage for 28 consecutive days in 6-week-old Kunming mice, aiming to explore the potential mechanisms underlying intestinal injury. The results demonstrate that CTN can cause structural damage to the mouse jejunum. Additionally, CTN reduces the protein expression of Claudin-1, Occludin, ZO-1, and MUC2, thereby disrupting the physical and chemical barriers of the intestine. Furthermore, exposure to CTN alters the structure of the intestinal microbiota in mice, thus compromising the intestinal microbial barrier. Meanwhile, the results showed that CTN exposure could induce excessive apoptosis in intestinal cells by altering the expression of proteins such as CHOP and GRP78 in the endoplasmic reticulum and Bax and Cyt c in mitochondria. The mitochondria and endoplasmic reticulum are connected through the mitochondria-associated endoplasmic reticulum membrane (MAM), which regulates the membrane. We found that the expression of bridging proteins Fis1 and BAP31 on the membrane was increased after CTN treatment, which would exacerbate the endoplasmic reticulum dysfunction, and could activate proteins such as Caspase-8 and Bid, thus further inducing apoptosis via the mitochondrial pathway. Taken together, these results suggest that CTN exposure can cause intestinal damage by disrupting the intestinal barrier and inducing excessive apoptosis in intestinal cells.

Coinfection with Schistosoma mansoni Enhances Disease Severity in Human African Trypanosomiasis

Introduction

Human African trypanosomiasis (HAT) and schistosomiasis are neglected parasitic diseases found in the African continent. This study was conducted to determine how primary infection with Schistosoma mansoni affects HAT disease progression with a secondary infection with Trypanosoma brucei rhodesiense (T.b.r) in a mouse model.

Methods

Female BALB-c mice (6-8 weeks old) were randomly divided into four groups of 12 mice each. The different groups were infected with Schistosoma mansoni (100 cercariae) and Trypanosoma brucei rhodesiense (5.0 × 104) separately or together. Twenty-one days after infection with T.b.r, mice were sacrificed and samples were collected for analysis.

Results

The primary infection with S. mansoni significantly enhanced successive infection by the T.b.r; consequently, promoting HAT disease severity and curtailing host survival time. T.b.r-induced impairment of the neurological integrity and breach of the blood-brain barrier were markedly pronounced on coinfection with S. mansoni. Coinfection with S. mansoni and T.b.r resulted in microcytic hypochromic anemia characterized by the suppression of RBCs, hematocrit, hemoglobin, and red cell indices. Moreover, coinfection of the mice with the two parasites resulted in leukocytosis which was accompanied by the elevation of basophils, neutrophils, lymphocytes, monocytes, and eosinophils. More importantly, coinfection resulted in a significant elevation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin, creatinine, urea, and uric acid, which are the markers of liver and kidney damage. Meanwhile, S. mansoni-driven dyslipidemia was significantly enhanced by the coinfection of mice with T.b.r. Moreover, coinfection with S. mansoni and T.b.r led to a strong immune response characterized by a significant increase in serum TNF-α and IFN-γ. T.b.r infection enhanced S. mansoni-induced depletion of cellular-reduced glutathione (GSH) in the brain and liver tissues, indicative of lethal oxidative damage. Similarly, coinfection resulted in a significant rise in nitric oxide (NO) and malondialdehyde (MDA) levels.

Conclusion

Primary infection with S. mansoni exacerbates disease severity of secondary infection with T.b.r in a mouse model that is associated with harmful inflammatory response, oxidative stress, and organ injury.

Evaluation of Immunomodulatory Effects of Fusarium Mycotoxins Using Bacterial Endotoxin-Stimulated Bovine Epithelial Cells and Macrophages in Co-Culture

Mycotoxins are secondary metabolites produced by a variety of fungi that contaminate animal food and feeds and are capable of inducing a wide range of toxicities. Predictive in vitro models represent valuable substitutes for animal experiments to assess the toxicity of mycotoxins. The complexities of the interactions between epithelial and innate immune cells, vital for upholding barrier integrity and averting infections, remain inadequately understood. In the current study, a co-culture model of bovine epithelial cells (MAC-T) and macrophages (BoMac) was used to investigate the impact of exposure to Fusarium mycotoxins, namely deoxynivalenol (DON), zearalenone (ZEN), enniatin B (ENB), and beauvericin (BEA), on the inflammatory response elicited by the bacterial lipopolysaccharide (LPS) endotoxin. The MAC-T cells and BoMac were seeded on the apical side of a Transwell membrane and in the lower chamber, respectively, and mycotoxin exposure on the apical side of the membrane was carried out with the different mycotoxins (LC20; concentrations that elicited 20% cytotoxicity) for 48 h followed by an LPS immunity challenge for 24 h. The culture supernatants were collected from the basolateral compartment and these samples were submitted for cytokine/chemokine multiplex analysis. RNA-Seq analysis was performed using total RNA extracted from the MAC-T cells to acquire a more detailed insight into their cellular functions. The multiplex analysis indicated that IFN-γ, IL-1α, IL-8, and MCP-1 were significantly induced post-DON treatment when compared to control cells, and levels of IL-1α and IL-8 were enhanced significantly in all mycotoxin-treated groups post-LPS challenge. Analysis of the sequencing results showed that there were 341, 357, and 318 differentially expressed MAC-T cell genes that were up-regulated in the DON, ENB, and BEA groups, respectively. Gene ontology and pathway analysis revealed that these DEGs were significantly enriched in various biological processes and pathways related to inflammation, apoptosis signaling, and Wnt signaling. These results provide a comprehensive analysis of the co-culture cytokine/chemokine production and MAC-T cells' gene expression profiles elicited by Fusarium mycotoxins, which further contributes to the understanding of early endotoxemia post-mycotoxin exposure.

Citrinin as a potential anti-cancer therapy: A comprehensive review

Citrinin (CIT) is a polyketide-derived mycotoxin, which is produced by many fungal strains belonging to the gerena Monascus, Aspergillus, and Penicillium. It has been postulated that mycotoxins have several toxic mechanisms and are potentially used as antineoplastic agents. Therefore, the present study carried out a systematic review, including articles from 1978 to 2022, by collecting evidence in experimental studies of CIT antiplorifactive activity in cancer. The Data indicate that CIT intervenes in important mediators and cell signaling pathways, including MAPKs, ERK1/2, JNK, Bcl-2, BAX, caspases 3,6,7 and 9, p53, p21, PARP cleavage, MDA, reactive oxygen species (ROS) and antioxidant defenses (SOD, CAT, GST and GPX). These factors demonstrate the potential antitumor drug CIT in inducing cell death, reducing DNA repair capacity and inducing cytotoxic and genotoxic effects in cancer cells.

Ochratoxin A and Citrinin Differentially Modulate Bovine Mammary Epithelial Cell Permeability and Innate Immune Function

Frequent detection of mycotoxins ochratoxin A (OTA) and citrinin (CIT) in ruminant feed and feedstuff can be a potential threat to feed safety, animal performance and health. Ineffective biodegradation of these mycotoxins by rumen microflora following ingestion of contaminated feeds can lead to their circulatory transport to tissues such as mammary gland as the result of their biodistribution throughout the body. The bovine mammary epithelium plays a pivotal role in maintaining milk yield and composition and contributes to innate immune defense of the udder. The present study is the first to investigate individual effects of OTA and CIT on barrier and innate immune functions of the bovine mammary epithelium using a bovine mammary epithelial cell line (MAC-T). Results indicated that OTA and CIT exposure for 48 h significantly decreased cell viability in a concentration-dependent manner (p < 0.05). A decrease in transepithelial electrical resistance and increase in paracellular flux of FITC-40 kDa dextran was significantly induced by OTA treatment (p < 0.05), but not by CIT after 48 h exposure. qPCR was performed for assessment of expression of tight-junction proteins, Toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48 h of exposure. Both OTA and CIT markedly downregulated expression of claudin 3 and occludin (p < 0.05), whereas CIT did not affect zonula occludens-1 expression. Expression of TLR4 was significantly upregulated by OTA (p < 0.001) but downregulated by CIT (p < 0.05) at 48 h. Expression of IL-6, TNF-a and TGF-β was significantly upregulated by OTA (p < 0.05), whereas IL-6 and TGF-β expression was downregulated by CIT (p < 0.01). These results suggest that OTA and CIT could potentially differentially modulate barrier and innate immune functions of mammary epithelium. The present study not only throws light on the individual toxicity of each mycotoxin on bovine mammary epithelium but also lays the foundation for future studies on the combined effects of the two mycotoxins.

PCV2 infection aggravates OTA-induced immunotoxicity in vivo and in vitro

Ochratoxin A (OTA), frequently existing in the food and feeds, could induce immunotoxicity. Porcine circovirus type 2 (PCV2), as a primary causative agent of porcine circovirus-associated disease, also could induce immunosuppression. However, it is still unknown whether PCV2 infection impacts OTA-induced immunotoxicity. The pigs and porcine alveolar macrophages (PAMs) were used as the model in the present experiment. The results in vivo indicated that PCV2 infection exacerbated OTA-induced immunotoxicity, NF-κB p65 phosphorylation, and TLR4 and MyD88 mRNA and protein expression in spleen. The results in vitro showed that OTA at 7.0 and 9.0 μM decreased cell viability and increased LDH release of PAMs without PCV2 infection. However, with PCV2 infection, OTA at 5.0, 7.0 and 9.0 μM significantly decreased cell viability and increased LDH release compared with absence of PCV2 infection. In addition, OTA at 5.0 and 7.0 μM significantly increased Annexin V/PI-positive rate, apoptosis of nuclear, γ-H2AX foci, IL-1α and TNF-α expression in PAMs with PCV2 infection compared with absence of PCV2 infection. In addition, PCV2 infection enhanced OTA-induced TLR4 and MyD88 mRNA and protein expression and NF-κB p65 phosphorylation. Knockdown of TLR4 alleviated the exacerbating effects of PCV2 infection on OTA-induced cytotoxicity, apoptosis and DNA damage in PAMs. These results indicated that PCV2 infection aggravated OTA-induced immunotoxicity and reduced the dose of OTA-induced immunotoxicity via TLR4/NF-κB p65 signaling pathway, which could provide basis for establishing limits for OTA.

The Compromised Intestinal Barrier Induced by Mycotoxins

Mycotoxins are fungal metabolites that occur in human foods and animal feeds, potentially threatening human and animal health. The intestine is considered as the first barrier against these external contaminants, and it consists of interconnected physical, chemical, immunological, and microbial barriers. In this context, based on in vitro, ex vivo, and in vivo models, we summarize the literature for compromised intestinal barrier issues caused by various mycotoxins, and we reviewed events related to disrupted intestinal integrity (physical barrier), thinned mucus layer (chemical barrier), imbalanced inflammatory factors (immunological barrier), and dysfunctional bacterial homeostasis (microbial barrier). We also provide important information on deoxynivalenol, a leading mycotoxin implicated in intestinal dysfunction, and other adverse intestinal effects induced by other mycotoxins, including aflatoxins and ochratoxin A. In addition, intestinal perturbations caused by mycotoxins may also contribute to the development of mycotoxicosis, including human chronic intestinal inflammatory diseases. Therefore, we provide a clear understanding of compromised intestinal barrier induced by mycotoxins, with a view to potentially develop innovative strategies to prevent and treat mycotoxicosis. In addition, because of increased combinatorial interactions between mycotoxins, we explore the interactive effects of multiple mycotoxins in this review.

Citrinin exposure disrupts organelle distribution and functions in mouse oocytes

Citrinin (CTN) is a secondary fungal metabolite produced by several species of Aspergillins and Penicillins, and it is widely found in vegetable-derived foods such as cereals and fermented rice-based food supplements. Previous studies indicated that CTN had immunotoxicity, hepatotoxicity, nephrotoxicity, and reproductive toxicity, which caused severe effects on human and animal health. However, the potential toxicity of CTN on the organelles of mouse oocytes is still unclear. In this study, we showed that the exposure to 30 μM CTN significantly reduced the developmental capacity of mouse oocytes. Our results revealed that mitochondria exhibited abnormal distribution and mitochondrial membrane potential decreased under CTN exposure. And the endoplasmic reticulum (ER) failed to accumulate to the spindle periphery, which is accompanied by the occurrence of ER stress, showing with increased GRP78 expression. We also found that similar with ER, the Golgi apparatus showed homogenous localization pattern after CTN exposure, and the vesicle transport was disturbed, showing with aberrant expression and localization of Rab11a. Moreover, our results indicated that CTN exposure increased the expression of LAMP2, indicating the induction of lysosomal damage. In summary, our study showed that CTN exposure to mouse oocytes was toxic to the distribution and functions of organelles, which further led to a decrease of oocyte quality.

Mitochondrial Dysfunction in Aged Macrophages and Lung during Primary Streptococcus pneumoniae Infection is Improved with Pirfenidone

Pneumococcal infections remain a leading cause of death in older adults, with the most serious cases occurring in persons ≥65 years of age. There is an urgent need to investigate molecular pathways underlying these impairments and devise new therapeutics to modulate innate immunity. The goal of our current study is to understand the impact of chronological aging on mitochondrial function in response to Streptococcus pneumoniae, a causative agent of bacterial pneumonia. Using chronologically aged murine models, our findings demonstrate that decreased ATP production is associated with dysregulated mitochondrial complex expression, enhanced oxidative stress, diminished antioxidant responses, and decreased numbers of healthy mitochondria in aged adult macrophages and lung in response to S. pneumoniae. Pre-treatment of aged macrophages with pirfenidone, an anti-fibrotic drug with antioxidant and anti-inflammatory properties, improved mitochondrial function and decreased cellular oxidative stress responses. In vivo administration of pirfenidone decreased superoxide formation, increased healthy mitochondria number, improved ATP production, and decreased inflammatory cell recruitment and pulmonary oedema in aged mouse lung during infection. Taken together, our data shed light on the susceptibility of older persons to S. pneumoniae and provide a possible therapeutic to improve mitochondrial responses in this population.

PRESENCE OF CITRININ IN GRAINS AND ITS POSSIBLE HEALTH EFFECTS

Background:

Citrinin is a mycotoxin produced by several species of the genera Aspergillus, Penicillium and Monascus and it occurs mainly in stored grain. Citrinin is generally formed after harvest and occurs mainly in stored grains, it also occurs in other plant products. Often, the co-occurrence with other mycotoxins is observed, especially ochratoxin A, which is usually associated with endemic nephropathy. At the European Union level, systematic monitoring of Citrinin in grains began with the aim of determining its highest permissible amount in food. Thus, far the systematic monitoring of the above mentioned mycotoxin in Croatia is yet to begin.

Materials and Methods:

The main goal of this study was to determine the presence of Citrinin in grains sampled in the area of Međimurje, Osijek-Baranja, Vukovar-Srijem and Brod-Posavina County. For the purpose of identification and quantification of citrinin, high performance liquid chromatograph (HPLC) with fluorescence was used (Calibration curve k > 0.999; Intra assay CV = 2.1%; Inter assay CV = 4.3%; LOQ < 1 μg/kg).

Results:

From the area of Međimurje County, 10 samples of corn and 10 samples of wheat were analyzed. None of the samples contained Citrinin (<1 μg/kg). From the area of Osijek-Baranja and Vukovar-Srijem County, 15 samples from each County were analyzed. The mean value for the samples of Osijek-Baranja County was 19.63 μg/kg (median=15.8 μg/kg), while for Vukovar-Srijem County the mean value of citrinin was 14,6 μg/kg (median=1.23 μg/kg). From 5 analyzed samples from Brod-Posavina County, one of the samples contained citrinin in the amount of 23.8 μg/kg, while the registered amounts in the other samples were <1 μg/kg.

Conclusion:

The results show that grains from several Counties contain certain amounts of Citrinin possibly indicating a significant intake of citrinin in humans. It must be stated that grains and grain-based products are the basis of everyday diet of all age groups, especially small children, where higher intake of citrinin can occur. Consequently, we emphasize the need for systematic analysis of larger amount of samples, from both large grains and small grains, especially in the area of Brod-Posavina County, in order to obtain more realistic notion of citrinin contamination of grains and to asses the health risk in humans.

Effect of Penicillium mycotoxins on the cytokine gene expression, reactive oxygen species production, and phagocytosis of bovine macrophage (BoMacs) function

Bovine macrophages (BoMacs) were exposed to the following Penicillium mycotoxins (PM): citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA) and penicillic acid (PA). PM exposure at the concentration that inhibits proliferation by 25% (IC25) differentially for 24h altered the gene expression of various cytokines. OTA significantly induced IL-1α expression (p<0.05), while the expression of IL-6 was suppressed (p<0.01). MPA significantly induced the expression of IL-1α (p<0.05) and reduced the expression of IL-12α (p<0.01) and IL-10 (p<0.01). PAT significantly suppressed the expression of IL-23 (p<0.01), IL-10 (p<0.05) and TGF-β (p<0.05). Some PMs also affected reactive oxygen species (ROS) and phagocytosis of Mycobacterium avium ssp. Paratuberculosis (MAP) at higher concentrations. PAT and PA for example, significantly decreased the percent phagocytosis of MAP at 5.0 (p<0.01) and 15.6 μM (p<0.01), respectively, but only PA significantly suppressed PAM-3-stimulated ROS production at 62.5 (p<0.05) and 250.0 μM (p<0.01). OTA significantly increased the percent phagocytosis of MAP at 6.3 (p<0.05) and 12.5 μM (p<0.01). These findings suggest that exposure to sub-lethal concentrations of PMs can affect macrophage function, which could affect immunoregulation and innate disease resistance to pathogens.

Hepatotoxic effect of ochratoxin A and citrinin, alone and in combination, and protective effect of vitamin E: In vitro study in HepG2 cell

Ochratoxin A (OTA) and citrinin (CTN) are the most commonly co-occurring mycotoxins in a wide variety of food and feed commodities. The major target organ of these toxins is kidney but liver could also be a target organ. The combined toxicity of these two toxins in kidney cells has been studied but not in liver cell. In this study HepG2 cells were exposed to OTA and CTN, alone and in combination, with a view to compare the molecular and cellular mechanisms underlying OTA, CTN and OTA + CTN hepatotoxicity. OTA and CTN alone as well as in combination affected the viability of HepG2 cells in a dose-dependent manner. OTA + CTN, at a dose of 20% of IC50 of each, produced effect almost similar to that produced by either of the toxins at its IC50 concentration, indicating that the two toxins in combination act synergistically. The cytotoxicity of OTA + CTN on hepatocytes is mediated by increased level of intracellular ROS followed/accompanied by DNA strand breaks and mitochondria-mediated intrinsic apoptosis. Co-treatment of vitamin E (Vit E) with OTA, CTN and OTA + CTN reduced the levels of ROS and the cytotoxicity. But the genotoxic effect of OTA and OTA + CTN was not completely alleviated by Vit E treatment whereas the DNA damage as caused by CTN when treated alone was obviated, indicating that OTA induces DNA damage directly whereas CTN induces ROS-mediated DNA damage and OTA + CTN combination induces DNA damage not exclusively relying on but influenced by ROS generation. Taken together, these findings indicate that OTA and CTN in combination affect hepatocytes at very low concentrations and, thereby, pose a potential threat to public and animal health.