Bacillus amyloliquefaciens B10 inhibits aflatoxin B1-induced cecal inflammation in mice by regulating their intestinal flora

Unveiling gut microbiota's role: Bidirectional regulation of drug transport for improved safety

Drug safety is a paramount concern in the field of drug development, with researchers increasingly focusing on the bidirectional regulation of gut microbiota in this context. The gut microbiota plays a crucial role in maintaining drug safety. It can influence drug transport processes in the body through various mechanisms, thereby modulating their efficacy and toxicity. The main mechanisms include: (1) The gut microbiota directly interacts with drugs, altering their chemical structure to reduce toxicity and enhance efficacy, thereby impacting drug transport mechanisms, drugs can also change the structure and abundance of gut bacteria; (2) bidirectional regulation of intestinal barrier permeability by gut microbiota, promoting the absorption of nontoxic drugs and inhibiting the absorption of toxic components; (3) bidirectional regulation of the expression and activity of transport proteins by gut microbiota, selectively promoting the absorption of effective components or inhibiting the absorption of toxic components. This bidirectional regulatory role enables the gut microbiota to play a key role in maintaining drug balance in the body and reducing adverse reactions. Understanding these regulatory mechanisms sheds light on novel approaches to minimize toxic side effects, enhance drug efficacy, and ultimately improve drug safety. This review systematically examines the bidirectional regulation of gut microbiota in drug transportation from the aforementioned aspects, emphasizing their significance in ensuring drug safety. Furthermore, it offers a prospective outlook from the standpoint of enhancing therapeutic efficacy and reducing drug toxicity, underscoring the importance of further exploration in this research domain. It aims to provide more effective strategies for drug development and treatment.

Metagenomic analysis of the intestinal microbiome reveals the potential mechanism involved in Bacillus amyloliquefaciens in treating schistosomiasis japonica in mice

Schistosomiasis japonica is one of the neglected tropical diseases characterized by chronic hepatic, intestinal granulomatous inflammation and fibrosis, as well as dysbiosis of intestinal microbiome. Previously, the probiotic Bacillus amyloliquefaciens has been shown to alleviate the pathological injuries in mice infected with Schistosoma japonicum by improving the disturbance of the intestinal microbiota. However, the underlying mechanisms involved in this process remain unclear. In this study, metagenomics sequencing and functional analysis were employed to investigate the differential changes in taxonomic composition and functional genes of the intestinal microbiome in S. japonicum-infected mice treated with B. amyloliquefaciens. The results revealed that intervention with B. amyloliquefaciens altered the taxonomic composition of the intestinal microbiota at the species level in infected mice and significantly increased the abundance of beneficial bacteria. Moreover, the abundance of predicted genes in the intestinal microbiome was also significantly changed, and the abundance of xfp/xpk and genes translated to urease was significantly restored. Further analysis showed that Limosilactobacillus reuteri was positively correlated with several KEGG Orthology (KO) genes and metabolic reactions, which might play important roles in alleviating the pathological symptoms caused by S. japonicum infection, indicating that it has the potential to function as another effective therapeutic agent for schistosomiasis. These data suggested that treatment of murine schistosomiasis japonica by B. amyloliquefaciens might be induced by alterations in the taxonomic composition and functional gene of the intestinal microbiome in mice. We hope this study will provide adjuvant strategies and methods for the early prevention and treatment of schistosomiasis japonica.

IMPORTANCE

Targeted interventions of probiotics on gut microbiome were used to explore the mechanism of alleviating schistosomiasis japonica. Through metagenomic analysis, there were significant changes in the composition of gut microbiota in mice infected with Schistosoma japonicum and significant increase in the abundance of beneficial bacteria after the intervention of Bacillus amyloliquefaciens. At the same time, the abundance of functional genes was found to change significantly. The abundance of genes related to urease metabolism and xfp/xpk related to D-erythrose 4-phosphate production was significantly restored, highlighting the importance of Limosilactobacillus reuteri in the recovery and abundance of predicted genes of the gut microbiome. These results indicated potential regulatory mechanism between the gene function of gut microbiome and host immune response. Our research lays the foundation for elucidating the regulatory mechanism of probiotic intervention in alleviating schistosomiasis japonica, and provides potential adjuvant treatment strategies for early prevention and treatment of schistosomiasis japonica.

Effects of Dietary Aflatoxin B1 on Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) Growth, Intestinal Health, and Muscle Quality

This study investigated the effects of varying doses of dietary aflatoxin B1 (AFB1) on the growth, intestinal health, and muscle quality of hybrid grouper. Four diets with varying AFB1 concentrations (0, 30, 445, and 2,230 μg kg-1) were used. Elevating AFB1 concentrations led to a decline in growth indexes, specifically the weight gain rate and the specific growth rate, although the survival rate remained unchanged. Morphological indicators showed a dose-dependent decline with AFB1 exposure. Intestinal MDA content and hindgut reactive oxygen species (ROS) levels increased, while antioxidant indexes and digestive enzymes decreased with higher AFB1 levels. AFB1 negatively influenced hindgut tight junction protein and antioxidant-related gene expression while promoting inflammation-related gene expression. The presence of AFB1 in the experiment led to a decrease in beneficial intestinal bacteria, such as Prevotella, and an increase in harmful intestinal bacteria, such as Prevotellaceae_NK3B31_group. Muscle lipid and unsaturated fatty acid content significantly decreased, while muscle protein and liver AFB1 content increased dramatically with higher AFB1 concentrations. AFB1 caused myofibrillar cleavage and myofilament damage, leading to increased spaces between muscle fibers. In conclusion, diets with AFB1 levels exceeding 30 μg kg-1 inhibited hybrid grouper growth, while levels surpassing 445 μg kg-1 resulted in hindgut ROS accumulation, inflammation, elevated intestinal permeability, reduced digestive enzyme activity, and compromised muscle quality.

Probiotic Potential of Bacillus amyloliquefaciens Isolated from Tibetan Yaks

The Tibetan livestock sector is now ailing from many infectious ailments brought on by harmful microorganisms. Therefore, this research aimed to assess the probiotic potential and safety of Bacillus amyloliquefaciens isolated from yaks in the Tibet area to provide upper-edge strain resources for probiotics development. The four strains isolated from the intestine of yaks had been identified as Bacillus amyloliquefaciens after the 16S rRNA sequence. The ethanol, bile salt, and acid tolerance revealed that the isolates had significant tolerance levels. The antibiotics susceptibility assay showed that the strains were sensitive to commonly used antibiotics, while the antibacterial assay prevented the isolates from outperforming five harmful bacteria in terms of antibacterial potency. Moreover, it was evident that strain BA5 had the strongest activity to scavenge hydroxyl radical and reduce power. According to the animal experiment, no apparent pathological change was observed in intestinal tissue sections. Furthermore, the strain had a positive effect on promoting the development of jejunal villi referred to its safety. Therefore, more research is required into the bacteriostatic and antioxidant capabilities of isolates in animal production.

Bacillus amyloliquefaciens B10 Alleviates the Immunosuppressive Effects of Deoxynivalenol and Porcine Circovirus Type 2 Infection

As one of the most common mycotoxins, deoxynivalenol (DON) can contaminate a wide range of crops and foods. Porcine circovirus 2 (PCV2) is a kind of immunosuppressive virus, which can cause porcine circovirus associated disease (PCVD) in pig farms infected with PCV2. Pigs are extremely sensitive to DON, and PCV2-infected pig farms are often contaminated with DON. Our previous studies indicated that Bacillus amyloliquefaciens B10 (B10) has the potential to alleviate the toxicity of mycotoxins. The research was aimed at investigating the effects of Bacillus amyloliquefaciens B10 on the immunosuppressive effects caused by both DON and PCV2 infection. The results indicated that the expression of the PCV2 capsid protein CAP was significantly decreased after pretreatment with Bacillus amyloliquefaciens B10. Then, the effects of the Bacillus amyloliquefaciens B10 pretreatment on the type I interferon, antiviral protein and the antiviral signal pathway cGAS-STING was further investigated. The findings displayed that the expression of the type I interferon and antiviral protein were increased, while the IL-10 were decreased after pretreatment with Bacillus amyloliquefaciens B10. The inhibition of DON on the cGAS-STING signal pathway was relieved. Furthermore, it was found that this intervention effect was produced by inhibiting autophagy. In summary, Bacillus amyloliquefaciens B10 can mitigate the immunosuppressive effects of PCV2 and DON by inhibiting the production of autophagy.

Aflatoxin B1 Induces Inflammatory Liver Injury via Gut Microbiota in Mice

Aflatoxin B₁ (AFB₁), a potent food-borne hepatocarcinogen, is the most toxic aflatoxin that induces liver injury in humans and animals. Species-specific sensitivities of aflatoxins cannot be fully explained by differences in the metabolism of AFB₁ between animal species. The gut microbiota are critical in inflammatory liver injury, but it remains to reveal the role of gut microbiota in AFB₁-induced liver injury. Here, mice were gavaged with AFB₁ for 28 days. Then, the modulation of gut microbiota, colonic barrier, and liver pyroptosis and inflammation were analyzed. To further verify the direct role of gut microbiota in AFB₁-induced liver injury, mice were treated with antibiotic mixtures (ABXs) to deplete the microbiota, and fecal microbiota transplantation (FMT) was conducted. The treatment of AFB₁ in mice altered gut microbiota composition, such as increasing the relative abundance of Bacteroides, Parabacteroides, and Lactobacillus, inducing colonic barrier dysfunction and promoting liver pyroptosis. In ABX-treated mice, AFB₁ had little effect on the colonic barrier and liver pyroptosis. Notably, after FMT, in which the mice were colonized with gut microbiota from AFB₁-treated mice, colonic barrier dysfunction, and liver pyroptosis and inflammation were obliviously identified. We proposed that the gut microbiota directly participated in AFB₁-induced liver pyroptosis and inflammation. These results provide new insights into the mechanisms of AFB₁ hepatotoxicity and pave a window for new targeted interventions to prevent or reduce AFB₁ hepatotoxicity.

Penthorum chinense Pursh compound flavonoids supplementation alleviates Aflatoxin B1-induced liver injury via modulation of intestinal barrier and gut microbiota in broiler

Aflatoxin B1 (AFB1) is a commonly occurring toxicant in animal and human diets, leading to hazardous effects on health. AFB1 is known to be a hepato-toxicant, and the intestinal barrier may play a crucial role in reversing AFB1-induced liver injury. This study aimed to optimize the extraction conditions of Penthorum chinense Pursh Compound Flavonoids (PCPCF) by the response surface method with a Box-Behnken design and investigate the effects of PCPCF on AFB1-induced liver injury in broilers. A total of 164 one-day-old broilers were divided into seven groups, including Control, PCPCF (400 mg PCPCF/kg feed), AFB1 (3 mg AFB1/kg feed), and YCHT (Yin-Chen-Hao-Tang extract, 3 mg AFB1 +10 mL YCHT/kg feed) and low, medium, and high dose groups (PCPCF at 3 mg AFB1 +200, 400, 600 mg respectively). Samples of serum, liver, duodenum, and cecum contents were collected at 14th and 28th days for further analysis. The results showed that the maximum extraction rate of PCPCF was 8.15 %. PCPCF was rich in rutin, quercetin, liquiritin and kaempferol, and significantly inhibited the growth of Aspergillus flavus. The addition of PCPCF improved the growth performance of AFB1-injury broilers, modulated liver function, and increased serum immunoglobulin levels. PCPCF also alleviated liver pathological and oxidative stress damages caused by AFB1 and decreased AFB1-DNA and AFB1-lysine content in the liver. Furthermore, PCPCF supplementation ameliorated intestinal pathological damage, improved intestinal permeability of duodenum in the AFB1-induced broilers, and repaired the intestinal mucosal and mechanical barrier associated with the Notch signaling pathway. Meanwhile, PCPCF improved the intestinal flora structure of AFB1-damaged broilers and increased the abundance of beneficial bacteria. In conclusion, PCPCF ameliorated the adverse effects of AFB1 on growth performance and alleviated liver damage by repairing the intestinal barrier and improving intestinal health of broiler chicken.

Total Flavonoids of Rhizoma Drynariae Mitigates Aflatoxin B1-Induced Liver Toxicity in Chickens via Microbiota-Gut-Liver Axis Interaction Mechanisms

Aflatoxin B1 (AFB1) is a common mycotoxin that widely occurs in feed and has severe hepatotoxic effects both in humans and animals. Total flavonoids of Rhizoma Drynaria (TFRD), a traditional Chinese medicinal herb, have multiple biological activities and potential hepatoprotective activity. This study investigated the protective effects and potential mechanisms of TFRD against AFB1-induced liver injury. The results revealed that supplementation with TFRD markedly lessened broiler intestinal permeability by increasing the expression of intestinal tight junction proteins, as well as correcting the changes in gut microbiota and liver damage induced by AFB1. Metabolomics analysis revealed that the alterations in plasma metabolites, especially taurolithocholic acid, were significantly improved by TFRD treatment in AFB1-exposed chickens. In addition, these metabolites were closely associated with [Ruminococcus], ACC, and GPX1, indicating that AFB1 may cause liver injury by inducing bile acid metabolism involving the microbiota–gut–liver axis. We further found that TFRD treatment markedly suppressed oxidative stress and hepatic lipid deposition, increased plasma glutathione (GSH) concentrations, and reversed hepatic ferroptosis gene expression. Collectively, these findings indicate that ferroptosis might contribute to the hepatotoxicity of AFB1-exposed chickens through the microbiota–gut–liver axis interaction mechanisms; furthermore, TFRD was confirmed as an herbal extract that could potentially antagonize mycotoxins detrimental effects.

Immunotoxicity of Three Environmental Mycotoxins and Their Risks of Increasing Pathogen Infections

Aflatoxin B1 (AFB1), ochratoxin A (OTA), and deoxynivalenol (DON) are the three mycotoxins that have received the most scholarly attention and have been tested most routinely in clinics. These mycotoxins not only suppress immune responses but also induce inflammation and even increase susceptibility to pathogens. Here, we comprehensively reviewed the determining factors for the bidirectional immunotoxicity of the three mycotoxins, their effects on pathogens, and their action mechanisms. The determining factors include mycotoxin exposure doses and times, as well as species, sex, and some immunologic stimulants. Moreover, mycotoxin exposure can affect the infection severity of some pathogens, including bacteria, viruses, and parasites. Their specific action mechanisms include three aspects: (1) mycotoxin exposure directly promotes the proliferation of pathogenic microorganisms; (2) mycotoxins produce toxicity, destroy the integrity of the mucosal barrier, and promote inflammatory response, thereby improving the susceptibility of the host; (3) mycotoxins reduce the activity of some specific immune cells and induce immune suppression, resulting in reduced host resistance. The present review will provide a scientific basis for the control of these three mycotoxins and also provide a reference for research on the causes of increased subclinical infections.

Crosstalk between Mycotoxins and Intestinal Microbiota and the Alleviation Approach via Microorganisms

Mycotoxins are secondary metabolites produced by fungus. Due to their widespread distribution, difficulty in removal, and complicated subsequent harmful by-products, mycotoxins pose a threat to the health of humans and animals worldwide. Increasing studies in recent years have highlighted the impact of mycotoxins on the gut microbiota. Numerous researchers have sought to illustrate novel toxicological mechanisms of mycotoxins by examining alterations in the gut microbiota caused by mycotoxins. However, few efficient techniques have been found to ameliorate the toxicity of mycotoxins via microbial pathways in terms of animal husbandry, human health management, and the prognosis of mycotoxin poisoning. This review seeks to examine the crosstalk between five typical mycotoxins and gut microbes, summarize the functions of mycotoxins-induced alterations in gut microbes in toxicological processes and investigate the application prospects of microbes in mycotoxins prevention and therapy from a variety of perspectives. The work is intended to provide support for future research on the interaction between mycotoxins and gut microbes, and to advance the technology for preventing and controlling mycotoxins.

Effects of sulfated polysaccharides from Laminaria japonica on regularating the gut microbiotan and alleviating intestinal inflammation in obese mice

Due to their known health-enhancing properties, Laminaria japonica polysaccharides (LJP) may alleviate obesity via unknown mechanisms. This study aimed to investigate beneficial LJP effects and mechanism(s) of action using an animal obesity model (ICR mice fed a high-fat diet). First, LJP were confirmed to consist of sulfated polysaccharides via infrared spectroscopy. Next, LJP administration to mice was found to induce weight loss, reduce liver fat accumulation, and support healthy obesity-related blood serum indicator levels. Notably, LJP treatment significantly reduced TC and LDL levels and significantly increased HDL, LPL, UCP-2, and PPAR-α levels. Furthermore, examinations of tissues of LJP-treated mice revealed significantly reduced intestinal tissue inflammation as compared to corresponding results obtained for untreated obese controls. Additionally, LJP treatment relieved colonic shortening and reduced colonic levels of inflammatory factors TNF-α and IL-6. Further exploration of LJP treatment effects on mouse gut microbiota conducted via fecal 16S rRNA gene sequence-based gut microbiome profiling analysis revealed that LJP treatment increased the Bacteroidetes/Firmicutes ratio and increased gut abundances of probiotics Bacteroides acidifaciens, s_Lactobacillus intestinalis, and s_Lactobacillus murinus. In conclusion, these results collectively suggest that LJP use as a food supplement may alleviate obesity and related gut microbiota dysbiosis and intestinal inflammatory disorders.

Effects of Bacillus subtilis natto JLCC513 on Gut Microbiota and Intestinal Barrier Function in obese Rats

AIMS

This study aimed to investigate the effects of Bacillus subtilis natto JLCC513(JLCC513)on gut microbiota, inflammation and intestinal barrier function in high-fat-diet (HFD) rats.

METHODS AND RESULTS

Sprague-Dawley (SD) rats were fed HFD for 16 weeks, and treated with JLCC513 in 9th weeks. The oral administration of JLCC513 decreased body weight, and reduced the inflammation level in HFD rats. Pathologically, JLCC513 prevented the detachment of ileal villus and increased the villus height in rat. Mechanistically, Western blot analysis showed that the protein levels of tight junction (TJ) proteins involved in intestinal barrier function, including zonula occludens-1 (ZO-1), occludin and claudin-1, were increased after JLCC513 treatment. Meanwhile, JLCC513 treatment also decreased the protein levels of toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) and NOD-like receptor protein 3 (NLRP3), indicating inhibition of the TLR4/NF-κB/NLRP3 pathway. Furthermore, fecal analysis showed that JLCC513 increased the abundance of Lactobacillus and Oscillospira and the ratio of Firmicutes/Bacteroidetes (F/B), and decreased the levels of Blautia and C_Clostridium.

CONCLUSIONS

JLCC513 alleviated intestinal barrier dysfunction by inhibiting TLR4/NF-κB/NLRP3 pathway and regulating gut microbiota disorders.

SIGNIFICANCE AND IMPACT OF STUDY

Our study might provide new treatment strategies for the obesity and metabolic diseases.

Effects of probiotic supplementation on very low dose AFB1-induced neurotoxicity in adult male rats

AIMS

Aflatoxin B1 (AFB1) is the most toxic and common form of AF found in food and feed. Although AFB1 exposure has toxic effects on many organs, studies on the brain are limited. Moreover, to the best of our knowledge, there is no study on the effect of probiotics on AFB1-induced neurotoxicity. Therefore, we aimed to evaluate the possible effects of probiotics on AFB1-induced neurotoxicity in the brain.

MAIN METHODS

Thirty-two adult male Wistar rats were divided into four groups: Vehicle (VEH), Probiotic (PRO) (2.5 × 10¹⁰ CFU/day VSL#3, orally), Aflatoxin B1 (AFB1) (25 μg/kg/week AFB1, orally), and Aflatoxin B1 + Probiotic (AFB1 + PRO) (2.5 × 10¹⁰ CFU/day VSL#3 + 25 μg/kg/week AFB1, orally). At the end of eight weeks, rats were behaviorally evaluated by the open field test, novel object recognition test, and forced swim test. Then, oxidative stress and inflammatory markers in brain tissues were analyzed. Next, brain sections were processed for Hematoxylin&Eosin staining and NeuN and GFAP immunostaining.

KEY FINDINGS

Probiotic supplementation tended to decrease oxidative stress and inflammatory markers compared to the AFB1 group. Besides, brain tissues had more normal histological structures in VEH, PRO, and AFB1 + PRO groups than in the AFB1 group. Moreover, in probiotic groups, GFAP immunoreactivity intensity was decreased, while NeuN-positive cell number increased in brain tissues compared to the AFB1 group.

SIGNIFICANCE

Probiotics seem to be effective at reducing the neurotoxic effects of AFB1. Thus, our study suggested that especially Bifidobacterium and Lactobacillus species can improve AFB1-induced neurotoxicity with their antioxidant and anti-inflammatory effects.

PINK1/Parkin-mediated mitophagy as a protective mechanism against AFB1-induced liver injury in mice

Aflatoxin B₁ (AFB₁) can cause oxidative stress leading to mitochondrial damage and subsequent liver injury. Although it is well-known that damaged mitochondria are eliminated by PINK1/Parkin-mediated mitophagy, this mechanism has not yet been characterized in the context of AFB₁-induced liver injury. In this study, male wild-type C57BL/6N mice were divided into groups 1-4, which were then orally administered 0, 0.5, 0.75, and 1 mg/kg body weight AFB₁ for 28 d, respectively. Our results demonstrated that oxidative stress, NLRP3-inflammasome activation, and mitochondrial damage were dose-dependently augmented in AFB₁-induced liver injury. Additionally, PINK1/Parkin-mediated mitophagy peaked in the groups that had received a mid-dose of AFB₁ (0.75 mg/kg), which was attenuated slightly in high-dose groups. Afterward, we further characterized AFB₁-induced liver injury by comparing wild-type C57BL/6N mice with Parkin knockout (Parkin^-/-) mice. We found that the restricted mitophagy in Parkin^-/- mice was associated with increased oxidative stress, NLRP3-inflammasome activation, mitochondrial damage, and liver injury. Taken together, these results indicate that PINK1/Parkin-mediated mitophagy plays an important role in attenuating AFB₁-induced liver injury in mice.