Commensal Lactobacillus Controls Immune Tolerance during Acute Liver Injury in Mice

Induction of Immune Responses in Mice and Newborn Piglets by Oral Immunization with Recombinant Lactococcus lactis Expressing S1 and M Proteins of Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea (PED) is a severe gastrointestinal disease caused by the porcine epidemic diarrhea virus (PEDV), a virus that spreads through the intestinal tract, leading to significant economic losses in the global swine industry. Therefore, compared to traditional injection method, developing vaccines that effectively stimulate the mucosal immune system to induce a protective immune response is crucial for PED prevention. This study evaluated the immunogenicity of recombinant Lactococcus lactis (L. lactis) strains expressing the PEDV S1 and M proteins (MG1363/pMG36e-S1 and MG1363/pMG36e-M) via oral administration in BALB/c mice and neonatal piglets, assessing cellular, humoral, and mucosal immune responses in the host. The results demonstrated that the recombinant strains significantly stimulated lymphocyte proliferation in mice and increased the proportion of CD3+, CD4+, and CD3+, CD8+ double-positive cells in the spleens of mice and the peripheral blood of piglets (p < 0.05). Furthermore, the recombinant strains significantly increased serum IgG, IgA, and mucosal SIgA levels in piglets (p < 0.05). Meanwhile, serum cytokine levels, including IL-4 and IFN-γ, were significantly elevated in piglets when compared to the control group (p < 0.05). In conclusion, the recombinant L. lactis demonstrated promising potential as a novel live vector vaccine against PEDV.

A comprehensive assessment of immunomodulatory potentials of Korean antler velvet extract in mouse and neurodegenerative Caenorhabditis elegans models

This study conducts a comprehensive analysis of deer antler velvet's impact, with a specific emphasis on mouse models and in vitro experiments. The study navigates the intricacies of antler velvet's variability, encompassing considerations of drying methods, extraction techniques, and anatomical regions of antlers. Employing a diverse array of processing methods, this study prioritizes both food safety and the consistent intake of deer antler velvet extracts. The study scrupulously evaluates toxicity and immune-boosting properties through exhaustive assessments, utilizing Caenorhabditis elegans, immunosuppressive mouse models, and immune cells. The study unfolds the repercussions of deer antler velvet extract on the lifespan, neuromuscular functions, and cognitive abilities of C. elegans. Additionally, this study explores the extract's potential to alleviate toxicity induced by cyclophosphamide (CPA) in a mouse model, with a focus on inflammation, metabolic disorders, and gut microbiota composition. The antler velvet extract prevents immune dysregulation caused by CPA treatment by ameliorating systemic inflammation and restoring energy metabolism. Furthermore, antler velvet extract treatment significantly transforms the gut microbiota of an immunosuppressive mouse model by fostering the proliferation of commensal bacteria such as Lactobacillus, Akkermansia, and Lachnospiraceae at the genus level. Moreover, antler velvet treatment enhances the activity of natural killer cells against YAC-1 lymphoma while tempering overactivity among immune cells to baseline levels. In conclusion, this study provides nuanced insights into the diverse benefits of antler velvet extract, encouraging sustained research to unveil its complete potential in the realms of mouse models and in vitro experiments.

The Influence of Protein Secretomes of Enterococcus durans on ex vivo Human Gut Microbiome

The gut microbiome plays a critical role to all animals and humans health. Methods based on ex vivo cultures are time and cost-effective solutions for rapid evaluation of probiotic effects on microbiomes. In this study, we assessed whether the protein secretome from the potential probiotic Enterococcus durans LAB18S grown on fructoligosaccharides (FOS) and galactoligosaccharides (GOS) had specific effects on ex vivo cultured intestinal microbiome obtained from a healthy individual. Metaproteomics was used to evaluate changes in microbial communities of the human intestinal microbiome. Hierarchical clustering analysis revealed 654 differentially abundant proteins from the metaproteome samples, showing that gut microbial protein expression varied on the presence of different E. durans secretomes. Increased amount of Bacteroidetes phylum was observed in treatments with secretomes from E. durans cultures on FOS, GOS and albumin, resulting in a decrease of the Firmicutes to Bacteroidetes (F/B) ratio. The most functionally abundant bacterial taxa were Roseburia, Bacteroides, Alistipes and Faecalibacterium. The results suggest that the secretome of E. durans may have favorable effects on the intestinal microbial composition, stimulating growth and different protein expression of beneficial bacteria. These findings suggest that proteins secreted by E. durans growing on FOS and GOS have different effects on the modulation of gut microbiota functional activities during cultivation.

Extraction and Identification of Polysaccharide from Lentinus edodes and Its Effect on Immunosuppression and Intestinal Barrier Injury Induced by Cyclophosphamide

Lentinus edodes serves as a significant source of both medicine and food, with its key component, lentinan (LNT), recognized as an effective immunomodulator. However, the mechanisms by which it regulates immune and intestinal functions under conditions of immunosuppression remain unclear. This study aims to investigate the components of lentinan and examine its potential effects on countering cyclophosphamide (CP)-induced immunosuppression, intestinal barrier damage, and dysregulation of gut microbiota. In this study, the effects of LNT were evaluated by serological indicators, histopathological changes in ileum, tight-junction-related protein expression, cytokine expression levels, and gut microbiota 16S rRNA gene sequencing. We found that LNT was effective in mitigating the abnormalities in body weight, immune organ index, and serum levels of IL-6, IL-2, IFN-γ, and IgG in mice induced by CP (p < 0.05). Furthermore, LNT demonstrated the ability to alleviate intestinal barrier damage induced by CP by increasing the mRNA levels of TNF-α, IL-1β, IFN-γ, Occludin, and ZO-1 (p < 0.05). Additionally, 16S rRNA gene sequencing revealed that LNT also normalized the disrupted abundance of Firmicutes, Proteobacteria, and Bacteroidets caused by CP. This restoration brought the gut microbiota back to normal levels and increased the abundance of certain tumor-inhibiting bacteria, such as Alistipes. Overall, lentinan demonstrated the ability to reverse the immunosuppressive effects induced by cyclophosphamide and modulate gut microbiota to restore a healthy microbial balance.

Lactobacillus rhamnosus GG ameliorates triptolide-induced liver injury through modulation of the bile acid-FXR axis

Triptolide (TP) is the principal bioactive compound of Tripterygium wilfordii with significant anti-tumor, anti-inflammatory and immunosuppressive activities. However, its severe hepatotoxicity greatly limits its clinical use. The underlying mechanism of TP-induced liver damage is still poorly understood. Here, we estimate the role of the gut microbiota in TP hepatotoxicity and investigate the bile acid metabolism mechanisms involved. The results of the antibiotic cocktail (ABX) and fecal microbiota transplantation (FMT) experiment demonstrate the involvement of intestinal flora in TP hepatotoxicity. Moreover, TP treatment significantly perturbed gut microbial composition and reduced the relative abundances of Lactobacillus rhamnosus GG (LGG). Supplementation with LGG reversed TP-induced hepatotoxicity by increasing bile salt hydrolase (BSH) activity and reducing the increased conjugated bile acids (BA). LGG supplementation upregulates hepatic FXR expression and inhibits NLRP3 inflammasome activation in TP-treated mice. In summary, this study found that gut microbiota is involved in TP hepatotoxicity. LGG supplementation protects mice against TP-induced liver damage. The underlying mechanism was associated with the gut microbiota-BA-FXR axis. Therefore, LGG holds the potential to prevent and treat TP hepatotoxicity in the clinic.

Interactions between toll-like receptors signaling pathway and gut microbiota in host homeostasis

BACKGROUND

Toll-like receptors (TLRs) are a family of fundamental pattern recognition receptors in the innate immune system, constituting the first line of defense against endogenous and exogenous antigens. The gut microbiota, a collection of commensal microorganisms in the intestine, is a major source of exogenous antigens. The components and metabolites of the gut microbiota interact with specific TLRs to contribute to whole-body immune and metabolic homeostasis.

OBJECTIVE

This review aims to summarize the interaction between the gut microbiota and TLR signaling pathways and to enumerate the role of microbiota dysbiosis-induced TLR signaling pathways in obesity, inflammatory bowel disease (IBD), and colorectal cancer (CRC).

RESULTS

Through the recognition of TLRs, the microbiota facilitates the development of both the innate and adaptive immune systems, while the immune system monitors dynamic changes in the commensal bacteria to maintain the balance of the host-microorganism symbiosis. Dysbiosis of the gut microbiota can induce a cascade of inflammatory and metabolic responses mediated by TLR signaling pathways, potentially resulting in various metabolic and inflammatory diseases.

CONCLUSION

Understanding the crosstalk between TLRs and the gut microbiota contributes to potential therapeutic applications in related diseases, offering new avenues for treatment strategies in conditions like obesity, IBD, and CRC.

GLP-1 receptor agonists alleviate colonic inflammation by modulating intestinal microbiota and the function of group 3 innate lymphoid cells

Glucagon-like peptide-1 receptor agonists (GLP-1RAs), which are drugs used for treating type 2 diabetes, have been reported to exert anti-inflammatory effects on inflammatory bowel disease (IBD), the mechanism of which remains elusive. Here, we report that GLP-1RAs ameliorate dextran sulfate sodium (DSS)-induced colitis in both wild-type and T/B-cell-deficient mice through modulating group 3 innate lymphoid cells (ILC3s), a subset of innate lymphoid cells that regulate intestinal immunity. GLP-1RAs promote IL-22 production by ILC3, and the protective effect of GLP-1RAs on DSS-induced colitis was abrogated in ILC3-deficient RORgtgfp/gfp mice. Furthermore, the treatment effect of GLP-RAs on colitis, as well as the generation of IL-22-producing ILC3s by GLP-RAs, is dependent on the gut microbiota. GLP-1RAs increase the abundance of Firmicutes and Proteobacteria in the gut, particularly beneficial bacteria such as Lactobacillus reuteri, and decrease the abundance of enteropathogenic Staphylococcus bacteria. The untargeted gas chromatography (GC)/liquid chromatography (LC)-mass spectrometry (MS) of faecal metabolites further revealed enrichment of N,N-dimethylsphingosine (DMS), an endogenous metabolite derived from sphingosine, in the GLP-1RA-treated group. Strikingly, DMS ameliorates colitis while promoting intestinal IL-22-producing ILC3s. Taken together, our findings show that GLP-1RAs exert a therapeutic effect on colitis possibly by regulating the microbiota-DMS-IL-22+ILC3 axis, highlighting the potential beneficial role of GLP-RAs in inflammatory intestinal disorders with diabetes complications.

Isolation of Calenduloside E from Achyranthes bidentata Blume and its effects on LPS/D-GalN-induced acute liver injury in mice by regulating the AMPK-SIRT3 signaling pathway

BACKGROUND

Acute liver injury (ALI) is a frequent fatal liver disease with a high mortality. Calenduloside E (CE) is a pentacyclic triterpenoid derived from Achyranthes bidentata Blume. It has been found that liver injury is associated with mitochondrial dysfunction, and activation of the AMPK-SIRT3 signaling pathway protects the mitochondrial function to play a role in resistance to the disease. However, whether CE is protective against ALI through the AMPK-SIRT3 signaling pathway is unclear.

PURPOSE

To clarify the influences of Calenduloside E (CE) isolated from Achyranthes bidentata Blume on LPS/D-GalN-induced Acute liver injury (ALI).

METHODS

A mouse model of ALI was developed, intraperitoneal injection of 10 μg/kg LPS and 700 mg/kg D-GalN, histopathological, oxidative stress, and immune inflammation of the mice were monitored. The mechanism of CE influencing liver injury was investigated by examining the gut microbiota, mitochondrial dysfunction, and the AMPK-SIRT3 signaling pathway. The antagonistic effects of specific AMPK and SIRT3 blocker, as well as AMPKα1, AMPKα2, SIRT3 transfection-mediated silencing were investigated to confirm the role of the AMPK-SIRT3 signaling pathway in this process.

RESULTS

CE relieved liver pathological damage of mice and led to reduced oxidative stress and immune inflammation in mice, affected the balance of gut microbiota in mice with liver injury, as well as energy metabolism, and regulated mRNA and protein expressions of AMPK-SIRT3 signaling pathway. In addition, in vitro studies showed that CE relieved mitochondrial respiratory and protein expressions of AMPK-SIRT3 signaling pathway in LPS/D-GalN-induced AML12 and LX2 cells, and such effect was blocked by AMPK and SIRT3 inhibitors. Furthermore, silencing of AMPKα1, AMPKα2, and SIRT3 blocked the effects of CE. Overall, the influences of CE on mice with liver injury is tuned by the AMPK-SIRT3 signaling pathway.

CONCLUSION

CE mediates mitochondrial function and eventually regulate energy metabolism by regulating the AMPK-SIRT3 signaling pathway. The results of this study provide molecular evidences for application of CE in treatment of ALI and provide references to the drug development for ALI.

Splenectomy ameliorates liver cirrhosis by restoring the gut microbiota balance

BACKGROUND

Dysbiosis of gut microbiota is frequent in liver cirrhosis (LC) patients, and splenectomy (SP) has been reported to improve LC. Herein, we report the effects of SP on gut microbiota, especially on Veillonella parvula, a Gram-negative coccus of the gastrointestinal tract, in LC mice, and the underlying mechanism.

METHODS

LC mice models were induced by tail vein injection of concanavalin A (ConA), followed by SP. 16 s rRNA sequencing was conducted to analyze the effects of ConA induction and SP on mouse gut microbiota and the gene expression affected by gut microbiota. LC mice receiving SP were gavaged with Veillonella parvula. Likewise, hepatic stellate cells (HSC) and hepatocytes (HC) were induced with conditioned medium (CM) of Veillonella parvula.

RESULTS

SP alleviated LC in mice by restoring gut barrier function and maintaining gut microbiota balance, with Veillonella as the key genus. The Veillonella parvula gavage on LC mice reversed the ameliorative effect of SP. The CM of Veillonella parvula promoted the activation of HSC and the release of IL-6, IL-1β, and TNF-α. Also, the CM of Veillonella parvula induced HC pyroptosis and the release of ALT and AST. Veillonella parvula represented an imbalance in the gut microbiota, thus enhancing gut-derived endotoxins in the liver with the main target being Tlr4/Nlrp3. Inhibition of Tlr4 blocked Veillonella parvula-induced HC damage, HSC activation, and subsequent LC progression.

CONCLUSION

SP-mediated gut microbiota regulation ameliorates ConA-related LC progression by inhibiting Tlr4/Nlrp3 in the liver.

Intestinal Microbiomics and Metabolomics Insights into the Hepatoprotective Effects of Lactobacillus paracasei CCFM1222 Against the Acute Liver Injury in Mice

In recent years, acute liver injury (ALI) has received wide-range attention in the world due to its relatively high morbidity and mortality. This study aimed to explore the hepatoprotective effect of Lactobacillus paracasei CCFM1222 against lipopolysaccharide (LPS)-induced ALI mice and further elaborate its mechanism of action from the perspective of intestinal microbiomics and metabolomics. The results displayed that L. paracasei CCFM1222 pretreatment significantly decreased the serum ALT, and AST levels, inhibited the releases of hepatic TNF-α, IL-1β, and IL-6 levels, and activated the SOD, CAT, and GSH-Px activities in LPS-treated mice. The cecal short-chain fatty acid (SCFAs) levels were increased in LPS-treated mice with L. paracasei CCFM1222 pretreatment. In addition, L. paracasei CCFM1222 pretreatment remarkably shifted the intestinal microbiota composition, including the higher abundance of Faecalibaculum, Bifidobacterium, and lower abundance of the Prevotellaceae NK3B31 group, which is positively associated with the cecal propionic, butyric, valeric, isobutyric, and isovaleric acids. The metabolomics based on UPLC-QTOF/MS revealed that L. paracasei CCFM1222 pretreatment significantly regulated the composition of feces metabolites in LPS-treated mice, especially the potential biomarker-related butanoate metabolism, vitamin B6 metabolism, D-glutamine and D-glutamate metabolism, tryptophan metabolism, caffeine metabolism, arginine biosynthesis, arginine, and proline metabolism. Moreover, L. paracasei CCFM1222 pretreatment remarkably regulated the expression of gene-associated ALI (including Tlr4, Myd88, Nf-kβ, iNOS, Cox2, Iκ-Bα, Nrf2, and Sirt-1). In conclusion, these results suggest the possibility that L. paracasei CCFM1222 supplementation has beneficial effects on preventing the occurrence and development of ALI by inhibiting the inflammatory responses and altering intestinal microbiota composition and their metabolites.

Oral Microbiota: The Influences and Interactions of Saliva, IgA, and Dietary Factors in Health and Disease

Recent advances in metagenomic analyses have made it easier to analyze microbiota. The microbiota, a symbiotic community of microorganisms including bacteria, archaea, fungi, and viruses within a specific environment in tissues such as the digestive tract and skin, has a complex relationship with the host. Recent studies have revealed that microbiota composition and balance particularly affect the health of the host and the onset of disease. Influences such as diet, food preferences, and sanitation play crucial roles in microbiota composition. The oral cavity is where the digestive tract directly communicates with the outside. Stable temperature and humidity provide optimal growth environments for many bacteria. However, the oral cavity is a unique environment that is susceptible to pH changes, salinity, food nutrients, and external pathogens. Recent studies have emphasized the importance of the oral microbiota, as changes in bacterial composition and balance could contribute to the development of systemic diseases. This review focuses on saliva, IgA, and fermented foods because they play critical roles in maintaining the oral bacterial environment by regulating its composition and balance. More attention should be paid to the oral microbiota and its regulatory factors in oral and systemic health.

Myeloid TLR4 signaling promotes post-injury withdrawal resolution of murine liver fibrosis

The fate of resolution of liver fibrosis after withdrawal of liver injury is still incompletely elucidated. Toll-like receptor 4 (TLR4) in tissue fibroblasts is pro-fibrogenic. After withdrawal of liver injury, we unexpectedly observed a significant delay of fibrosis resolution as TLR4 signaling was pharmacologically inhibited in vivo in two murine models. Single-cell transcriptome analysis of hepatic CD11b⁺ cells, main producers of matrix metalloproteinases (MMPs), revealed a prominent cluster of restorative Tlr4-expressing Ly6c2-low myeloid cells. Delayed resolution after gut sterilization suggested its microbiome-dependent nature. Enrichment of a metabolic pathway linking to a significant increase of bile salt hydrolase-possessing family Erysipelotrichaceae during resolution. Farnesoid X receptor-stimulating secondary bile acids including 7-oxo-lithocholic acids upregulated MMP12 and TLR4 in myeloid cells in vitro. Fecal material transplant in germ-free mice confirmed phenotypical correlations in vivo. These findings highlight a pro-fibrolytic role of myeloid TLR4 signaling after injury withdrawal and may provide targets for anti-fibrotic therapy.

Effects of supplementation of Bacillus amyloliquefaciens on performance, systemic immunity, and intestinal microbiota of weaned pigs experimentally infected with a pathogenic enterotoxigenic E. coli F18

The objective of this study was to investigate the effects of dietary supplementation of Bacillus (B.) amyloliquefaciens on growth performance, diarrhea, systemic immunity, and intestinal microbiota of weaned pigs experimentally infected with F18 enterotoxigenic Escherichia coli (ETEC). A total of 50 weaned pigs (7.41 ± 1.35 kg BW) were individually housed and randomly allotted to one of the following five treatments: sham control (CON-), sham B. amyloliquefaciens (BAM-), challenged control (CON+), challenged B. amyloliquefaciens (BAM+), and challenged carbadox (AGP+). The experiment lasted 28 days, with 7 days of adaptation and 21 days after the first ETEC inoculation. ETEC challenge reduced (P &lt; 0.05) average daily gain (ADG) of pigs. Compared with CON+, AGP+ enhanced (P &lt; 0.05) ADG, while B. amyloliquefaciens supplementation tended (P &lt; 0.10) to increase ADG in pigs from days 0 to 21 post-inoculation (PI). The ETEC challenge increased (P &lt; 0.05) white blood cell (WBC) count on days 7 and 21 PI, while BAM+ pigs tended (P &lt; 0.10) to have low WBC on day 7 PI and had lower (P &lt; 0.05) WBC on day 21 PI compared with CON+. In comparison to AGP+ fecal microbiota, BAM+ had a lower (P &lt; 0.05) relative abundance of Lachnospiraceae on day 0 and Clostridiaceae on day 21 PI, but a higher (P &lt; 0.05) relative abundance of Enterobacyeriaceae on day 0. In ileal digesta, the Shannon index was higher (P &lt; 0.05) in BAM+ than in AGP+. Bray-Curtis PCoA displayed a difference in bacterial community composition in ileal digesta collected from sham pigs vs. ETEC-infected pigs on day 21 PI. Pigs in BAM+ had a greater (P &lt; 0.05) relative abundance of Firmicutes, but a lower (P &lt; 0.05) relative abundance of Actinomycetota and Bacteroidota in ileal digesta than pigs in AGP+. Ileal digesta from AGP+ had a greater (P &lt; 0.05) abundance of Clostridium sensu stricto 1 but lower (P &lt; 0.05) Bifidobacterium than pigs in BAM+. In conclusion, supplementation of B. amyloliquefaciens tended to increase ADG and had limited effects on the diarrhea of ETEC-infected pigs. However, pigs fed with B. amyloliquefaciens exhibit milder systemic inflammation than controls. B. amyloliquefaciens differently modified the intestinal microbiota of weaned pigs compared with carbadox.

Potential Probiotic Properties of Blautia producta Against Lipopolysaccharide-Induced Acute Liver Injury

Blautia is a genus of anaerobic microbe extensively present in the intestine and feces of mammals. This study aims to investigate the influence of Blautia producta to prevent lipopolysaccharide (LPS)-induced acute liver injury (ALI) and elaborate on its hepatoprotective mechanisms. B. producta D4 and DSM2950 pretreatment decreased the activities of serum aspartate transferase (AST), and alanine transaminase (ALT) in mice with LPS treatment significantly decreased the levels of inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) and increased the activities of antioxidative superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Compared with the model group, B. producta D4 and B. producta DSM2950 pretreatment slightly increased the levels of cecal propionic acid, isobutyric acid, butyric acid, valeric acid, and isovaleric acid (p > 0.05). Metagenomic analysis showed that B. producta D4 and DSM2950 pretreatment remarkably increased the relative abundance of [Eubacterium] xylanophilum group, Lachnospira, Ruminiclostridium, Ruminiclostridium 9, Coprococcus 2, Odoribacter, Roseburia, Alistipes, and Desulfovibrio in ALI mice, and their abundance is negatively related to the levels of inflammatory TNF-α, IL-1β, and IL-6 as revealed by Spearman's correlation analysis. Moreover, transcription and immunohistochemistry analysis revealed that B. producta D4 and B. producta DSM2950 intervention remarkably suppressed the transcription and expression levels of hepatic Tlr4, MyD88, and caspase-3 (p < 0.05). These data indicated that B. producta may be a good candidate for probiotics in the prevention of ALI.

Microbial metabolites indole derivatives sensitize mice to D-GalN/LPS induced-acute liver failure via the Tlr2/NF-κB pathway

Introduction

Acute liver failure (ALF) is a clinical condition with many causes, fast progression, and a poor prognosis. Previous research has indicated that microbial factors have a role in ALF, but a clear picture has yet to emerge.

Methods

To investigate the specific involvement of microbial metabolites in ALF development, we pretreated D-GalN/LPS-induced ALF mice with indole derivatives, an influential class of gut microbial metabolites.

Results

Contrary to their typical role as anti-inflammatory agents in the host, indole-3-acetic acid (IAA), indole-3-lactic acid (ILA), and indolepropionic acid (IPA) gavage sensitize mice to D-GalN/LPS-induced-ALF with a rapid rise in serum transaminases and histologic lesion. For a clearer picture, we performed comprehensive analysis for the IAA therapy. IAA markedly amplified inflammatory response and cellular damage. The transcriptome analysis indicated the participation of the TNF-α/NF-κB signaling pathway. The structure of gut microbiota in ileum and the expression of Toll-like receptor 2 (Tlr2) in the liver were also significantly changed.

Discussion

In conclusion, IAA pretreatment can exacerbate D-GalN/LPS-induced ALF via probable Tlr2/NF-κB pathway involvement and ileac dysbiosis characterized by enriched gram-positive genus with potential pathogenesis. Microbial metabolites IAA may aggravate individual susceptibility to D-GalN/LPS-induced ALF. Further investigation of the underlying mechanism is needed, and intervention with indole derivatives and related commensal species should be undertaken with caution.

The effects of rhein on D-GalN/LPS-induced acute liver injury in mice: Results from gut microbiome-metabolomics and host transcriptome analysis

Background

Rhubarb is an important traditional Chinese medicine, and rhein is one of its most important active ingredients. Studies have found that rhein can improve ulcerative colitis by regulating gut microbes, but there are few reports on its effects on liver diseases. Therefore, this study aims to investigate these effects and underlying mechanisms.

Methods

Mice were given rhein (100 mg/kg), with both a normal control group and a model group receiving the same amount of normal saline for one week. Acute liver injury was induced in mice by intraperitoneal injection of D-GalN (800 mg/kg)/LPS (10 ug/kg). Samples (blood, liver, and stool) were then collected and assessed for histological lesions and used for 16S rRNA gene sequencing, high-performance liquid chromatography-mass spectrometry (LC-MS) and RNA-seq analysis.

Results

The levels of ALT and AST in the Model group were abnormal higher compared to the normal control group, and the levels of ALT and AST were significantly relieved in the rhein group. Hepatic HE staining showed that the degree of liver injury in the rhein group was lighter than that in the model group, and microbiological results showed that norank_o:Clostridia_UCG-014, Lachnoclostridium, and Roseburia were more abundant in the model group compared to the normal control group. Notably, the rhein treatment group showed reshaped disturbance of intestinal microbial community by D-GalN/LPS and these mice also had higher levels of Verrucomicrobia, Akkermansiaceae and Bacteroidetes. Additionally, There were multiple metabolites that were significantly different between the normal control group and the model group, such as L-α-amino acid, ofloxacin-N-oxide, 1-hydroxy-1,3-diphenylpropan-2-one,and L-4-hydroxyglutamate semialdehyde, but that returned to normal levels after rhein treatment. The gene expression level in the model group also changed significantly, various genes such as Cxcl2, S100a9, Tnf, Ereg, and IL-10 were up-regulated, while Mfsd2a and Bhlhe41 were down-regulated, which were recovered after rhein treatment.

Conclusion

Overall, our results show that rhein alleviated D-GalN/LPS-induced acute liver injury in mice. It may help modulate gut microbiota in mice, thereby changing metabolism in the intestine. Meanwhile, rhein also may help regulate genes expression level to alleviate D-GalN/LPS-induced acute liver injury.

Ameliorative Effect of Chitosan Oligosaccharides on Hepatic Encephalopathy by Reshaping Gut Microbiota and Gut-Liver Axis

This study investigated the influence of chitosan oligosaccharides (COSs) on a thioacetamide-induced hepatic encephalopathy (HE) Wistar rat model. COS treatment statistically reduced the false neurotransmitters and blood ammonia in HE rats, along with the suppression of oxidative stress and inflammation. The disbalanced gut microbiota was detected in HE rats by 16S rDNA sequencing, but the abundance alterations of some intestinal bacteria at either the phylum or genus level were at least partly restored by COS treatment. According to metabolomics analysis of rat feces, six metabolism pathways with the greatest response to HE were screened, several of which were remarkably reversed by COS. The altered metabolites might serve as a bridge for the alleviated HE rats treated with COS and the enhanced intestinal bacterial structure. This study provides novel guidance to develop novel food or dietary supplements to improve HE diseases due to the potential beneficial effect of COS on gut-liver axis.

The 16S rRNA Gene Sequencing of Gut Microbiota in Chickens Infected with Different Virulent Newcastle Disease Virus Strains

Simple Summary

Newcastle disease (ND), which is caused by virulent Newcastle disease virus (NDV), is one of the most important viral diseases for chickens and birds. However, the intestinal pathogenesis of NDV is still poorly understood. To preliminarily investigate its intestinal pathogenesis mechanisms from the aspect of gut microbiota, the 16S rRNA gene sequencing technology was used to evaluate the gut microbiota composition changes post different virulent NDV infection. Results showed that different virulent NDV infection resulted in a different alteration of the gut microbiota in chickens, including a loss of probiotic bacteria and an expansion of some pathogenic bacteria. The above results suggest that NDV strains with different virulence have different impacts on chicken gut microbiota.

Abstract

Newcastle disease virus (NDV) which is pathogenic to chickens is characterized by dyspnea, diarrhea, nervous disorder and hemorrhages. However, the influence of different virulent NDV strain infection on the host gut microbiota composition is still poorly understood. In this study, twenty 21-day-old specific pathogen free (SFP) chickens were inoculated with either the velogenic Herts33 NDV strain, lentogenic La Sota NDV strain or sterile phosphate buffer solution (PBS). Subsequently, the fecal samples of each group were collected for 16S rRNA sequencing. The results showed that the gut microbiota were mainly dominated by Firmicutes, Bacteroidetes and Proteobacteria in both healthy and NDV infected chickens. NDV infection altered the structure and composition of gut microbiota. As compared to the PBS group, phylum Firmicutes were remarkably reduced, whereas Proteobacteria was significantly increased in the velogenic NDV infected group; the gut community structure had no significant differences between the lentogenic NDV infected group and the PBS group at phylum level. At genus level, Escherichia-Shigella was significantly increased in both the velogenic and lentogenic NDV infected groups, but the lactobacillus was only remarkably decreased in the velogenic NDV infected group. Collectively, different virulent strain NDV infection resulted in a different alteration of the gut microbiota in chickens, including a loss of probiotic bacteria and an expansion of some pathogenic bacteria. These results indicated that NDV strains with different virulence have different impacts on chicken gut microbiota and may provide new insights into the intestinal pathogenesis of NDV.

Epigallocatechin-3-Gallate Improves Intestinal Gut Microbiota Homeostasis and Ameliorates Clostridioides difficile Infection

Clostridioides difficile infection is closely related to the intestinal flora disorders induced by antibiotics, and changes in the intestinal flora may cause the occurrence and development of Clostridioides difficile infection. Epigallocatechin-3-gallate (EGCG) is one of the major bioactive ingredients of green tea and has been suggested to alleviate the growth of C. difficile in vitro. EGCG can ameliorate several diseases, such as obesity, by regulating the gut microbiota. However, whether EGCG can attenuate C. difficile infection by improving the gut microbiota is unknown. After establishing a mouse model of C. difficile infection, mice were administered EGCG (25 or 50 mg/kg/day) or PBS intragastrically for 2 weeks to assess the benefits of EGCG. Colonic pathology, inflammation, the intestinal barrier, gut microbiota composition, metabolomics, and the transcriptome were evaluated in the different groups. Compared with those of the mice in the CDI group, EGCG improved survival rates after infection, improved inflammatory markers, and restored the damage to the intestinal barrier. Furthermore, EGCG could improve the intestinal microbial community caused by C. difficile infection, such as by reducing the relative abundance of Enterococcaceae and Enterobacteriaceae. Moreover, EGCG can increase short-chain fatty acids, improve amino acid metabolism, and downregulate pathways related to intestinal inflammation. EGCG alters the microbiota and alleviates C. difficile infection, which provides new insights into potential therapies.

CCR9 axis inhibition enhances hepatic migration of plasmacytoid dendritic cells and protects against liver injury

Plasmacytoid dendritic cells (pDCs) perform dual proinflammatory and immunosuppressive roles. We recently reported the potential of pDC therapy for treatment of intractable acute liver failure. However, establishment of efficient methods to deliver pDCs to the liver is essential for future clinical therapeutic applications. The present study demonstrates a higher abundance of liver and peripheral blood pDCs in mice lacking the C-C motif chemokine receptor 9 (CCR9), a pDC gut-homing receptor, than that in wild-type (WT) mice. Adoptive pDC transfer resulted in a higher efficiency of Ccr9-/- pDC migration to the liver than that to the original target organ, the small intestine, compared with that of WT pDCs. Further, Ccr9-/- pDCs consistently migrated efficiently to the concanavalin A-induced inflamed liver, and exerted a more effective immunosuppressive effect, resulting in better protection against acute liver inflammation than that demonstrated by WT pDCs. These findings highlight the therapeutic potential of the manipulation of CCR9 axis as a novel approach to improve migration of immunosuppressive pDCs to the liver in order to exploit their beneficial effects in acute liver disease.

Lactobacillus paracasei CCFM1223 Protects against Lipopolysaccharide-Induced Acute Liver Injury in Mice by Regulating the “Gut–Liver” Axis

Background: Lactobacillus paracasei CCFM1223, a probiotic previously isolated from the healthy people’s intestine, exerts the beneficial influence of preventing the development of inflammation. Methods: The aim of this research was to explore the beneficial effects of L. paracasei CCFM1223 to prevent lipopolysaccharide (LPS)-induced acute liver injury (ALI) and elaborate on its hepatoprotective mechanisms. Results: L. paracasei CCFM1223 pretreatment remarkably decreased the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in mice with LPS treatment and remarkably recovered LPS-induced the changes in inflammatory cytokines (tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), interleukin (IL)-1β, IL-6, IL-17, IL-10, and LPS) and antioxidative enzymes activities (total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT)). Metagenomic analysis showed that L. paracasei CCFM1223 pretreatment remarkably increased the relative abundance of Catabacter compared with the LPS group but remarkably reduced the relative abundance of [Eubacterium] xylanophilumgroup, ASF356, LachnospiraceaeNK4A136group, and Lachnoclostridium, which is closely associated with the inflammation cytokines and antioxidative enzymes. Furthermore, L. paracasei CCFM1223 pretreatment remarkably increased the colonic, serum, and hepatic IL-22 levels in ALI mice. In addition, L. paracasei CCFM1223 pretreatment remarkably down-regulated the hepatic Tlr4 and Nf-kβ transcriptions and significantly up-regulated the hepatic Tlr9, Tak1, Iκ-Bα, and Nrf2 transcriptions in ALI mice. Conclusions: L. paracasei CCFM1223 has a hepatoprotective function in ameliorating LPS-induced ALI by regulating the “gut–liver” axis.

Intestinal Microbiota - An Unmissable Bridge to Severe Acute Pancreatitis-Associated Acute Lung Injury

Severe acute pancreatitis (SAP), one of the most serious abdominal emergencies in general surgery, is characterized by acute and rapid onset as well as high mortality, which often leads to multiple organ failure (MOF). Acute lung injury (ALI), the earliest accompanied organ dysfunction, is the most common cause of death in patients following the SAP onset. The exact pathogenesis of ALI during SAP, however, remains unclear. In recent years, advances in the microbiota-gut-lung axis have led to a better understanding of SAP-associated lung injury (PALI). In addition, the bidirectional communications between intestinal microbes and the lung are becoming more apparent. This paper aims to review the mechanisms of an imbalanced intestinal microbiota contributing to the development of PALI, which is mediated by the disruption of physical, chemical, and immune barriers in the intestine, promotes bacterial translocation, and results in the activation of abnormal immune responses in severe pancreatitis. The pathogen-associated molecular patterns (PAMPs) mediated immunol mechanisms in the occurrence of PALI via binding with pattern recognition receptors (PRRs) through the microbiota-gut-lung axis are focused in this study. Moreover, the potential therapeutic strategies for alleviating PALI by regulating the composition or the function of the intestinal microbiota are discussed in this review. The aim of this study is to provide new ideas and therapeutic tools for PALI patients.

Study on the Characteristics of Intestinal Flora Composition in Gastric Cancer Patients and Healthy People in the Qinghai-Tibet Plateau

The aim of this study is to compare and analyze the structure and diversity of intestinal flora between gastric cancer patients and healthy people in the Qinghai-Tibet Plateau and to explore the characteristics of the intestinal flora composition in gastric cancer patients in the plateau area, and to determine the possible correlation between the intestinal flora and gastric cancer. Fresh feces from 22 cases of gastric cancer patients diagnosed in a tertiary hospital in Qinghai Province and 30 cases of healthy people during the same period were collected. The 52 subjects were undergone for 16S rDNA gene sequencing of intestinal bacteria to analyze and compare the diversity and compositional characteristics of intestinal flora. Analysis of the diversity of intestinal flora between the gastric cancer group and the healthy group was based on the Chao1 index of species richness, Shannon diversity index, and Simpson index. It showed that the gastric cancer group had no statistically difference from the healthy group (P > 0.05). In the Venn diagram, the number of OTU units shared by the gastric cancer group and the healthy group is 6997, and the number of unique OTU units in the healthy group is 2282, while the number of OTU units in the gastric cancer group is 896 and the difference is statistically significant (χ2 = 495.829), P < 0.000). Analysis of the composition and abundance distribution of intestinal flora showed that at the phylum level, there is no significant deference in abundance between the healthy group of Bacteroides and Firmicutes compared with the gastric cancer group (P > 0.05). However, there is a statistically significant difference in abundance between the healthy groups of Proteobacteria compared with the gastric cancer group (P < 0.05). At the genus level, the gastric cancer group of Prevotella_9 is significantly different from the healthy group (P < 0.05). Meanwhile, the gastric cancer group of Streptococcus and Lactobacillus are significantly different from the healthy group (P < 0.001). There are differences in the composition and abundance of intestinal flora between patients with gastric cancer and healthy people in plateau areas, suggesting that Proteobacteria, Prevotella_9, Streptococcus, and Lactobacillus have increased in the Qinghai-Tibet Plateau and becoming one of the factors related to the incidence of gastric cancer in the region.

Costunolide protects against alcohol-induced liver injury by regulating gut microbiota, oxidative stress and attenuating inflammation in vivo and in vitro

Costunolide (cos) derived from the roots of Dolomiaea souliei (Franch.), which belongs to the Dolomiaea genus in the family Compositae, exert the anti-inebriation effect mainly by inhibiting the absorption of alcohol in the gastrointestinal tract. However, the protective effect of cos against alcohol-induced liver injury (ALI) remains obscure. The present study was aimed to evaluate the hepatoprotective effects of cos (silymarin was used as positive control) against ALI and its potential mechanisms. MTT was used to examine the effect of cos on the cell viability of L-02 cells. Plasma was separated from blood that used to test the levels of TNF-α, IL-6 and IL-12, and LPS while serum separated from blood which used to detect the level of ALT and AST. Liver tissues were obtained for histopathological examination and western blot analysis. Fresh mice feces samples were collected for the detection of bacterial composition. Cos exhibited protective effect against alcoholic-induced liver injury by regulating gut microbiota capacities (higher relative abundance of Firmicutes and Actinobacteria while lower in Bacteroidetes and Proteobacteria), adjusting oxidative stress (reduced the activities of MDA and ROS while promoted SOD, GSH and GSH-PX in L-02 cells) and attenuating inflammation (decreased the levels of ALT, AST, LPS, IL-6, IL-12 and TNF-α) via LPS-TLR4-NF-κB p65 signaling pathway, which might be an active therapeutic agent for treatment of ALI.

A comprehensive update: gastrointestinal microflora, gastric cancer and gastric premalignant condition, and intervention by traditional Chinese medicine

With the recent upsurge of studies in the field of microbiology, we have learned more about the complexity of the gastrointestinal microecosystem. More than 30 genera and 1000 species of gastrointestinal microflora have been found. The structure of the normal microflora is relatively stable, and is in an interdependent and restricted dynamic equilibrium with the body. In recent years, studies have shown that there is a potential relationship between gastrointestinal microflora imbalance and gastric cancer (GC) and precancerous lesions. So, restoring the balance of gastrointestinal microflora is of great significance. Moreover, intervention in gastric premalignant condition (GPC), also known as precancerous lesion of gastric cancer (PLGC), has been the focus of current clinical studies. The holistic view of traditional Chinese medicine (TCM) is consistent with the microecology concept, and oral TCM can play a two-way regulatory role directly with the microflora in the digestive tract, restoring the homeostasis of gastrointestinal microflora to prevent canceration. However, large gaps in knowledge remain to be addressed. This review aims to provide new ideas and a reference for clinical practice.

Huganbuzure Granule Attenuates Concanavalin-A-Induced Immune Liver Injury in Mice via Regulating the Balance of Th1/Th2/Th17/Treg Cells and Inhibiting Apoptosis

In Uygur medicine, Huganbuzure granule (HBG) is one of the classical prescriptions for liver protection. However, its role in immune liver injury remains unknown. This study evaluates the effect of HBG on concanavalin-A- (ConA-) induced immune liver injury and investigates its protective underlying mechanism. BALB/c mice were randomly divided into five groups (n = 24 mice per group): control, ConA, 1.6 g/kg HBG + ConA, 3.2 g/kg HBG + ConA, and 6 mg/kg prednisolone + ConA. HBG was intragastrically administrated once daily for ten consecutive days, prior to ConA (20 mg/kg) injection. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), superoxide dismutase (SOD), and malondialdehyde (MDA) in mouse serum were measured after ConA injection. Moreover, liver-related mRNA levels were evaluated by qPCR. The detection of liver-related proteins was assessed by immunohistochemistry and western blot analysis. Compared with the ConA group, HBG reduced the mRNA expression of IL-17A and IFN-γ and the protein expression of T-bet and ROR-γt. In addition, HBG increased the mRNA expression of IL-4 and TGF-β and protein expression of GATA3 and Foxp3, indicating that HBG regulated the balance of Th1/Th2 and Th17/Treg. Furthermore, HBG alleviated immune liver injury by reducing oxidative stress, inhibiting apoptosis, and decreasing the expression of p-JNK, p-ERK, p-p38, p-JAK1, p-STAT1, p-STAT3, and IRF1. Our data suggested that HBG attenuated ConA-induced immune liver injury by regulating the immune balance and inhibiting JAK1/STATs/IRF1 signaling, thereby reducing apoptosis induced by JNK activation. The findings indicate that HBG may be a promising drug for immune liver injury.

Effect of the Fermentation Broth of the Mixture of Pueraria lobata, Lonicera japonica, and Crataegus pinnatifida by Lactobacillus rhamnosus 217-1 on Liver Health and Intestinal Flora in Mice With Alcoholic Liver Disease Induced by Liquor

In this work, we discovered a new fermentation broth that can prevent and regulate alcoholic liver disease (ALD) and intestinal flora, which fermented the mixture of Pueraria lobata, Lonicera japonica, and Crataegus pinnatifida by Lactobacillus rhamnosus 217-1. The contents of polyphenols, puerarin, total isoflavones, and amino acids were significantly increased. Animal experiments showed that the fermentation broth could improve the liver indexes of ALD mice model, increase the activity of superoxide dismutase and glutathione in liver tissue, and reduce the level of malondialdehyde (MDA). Furthermore, the fermentation broth can reduce the levels of serum lipopolysaccharide (LPS), inflammatory factors interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Importantly, intestinal flora analysis showed that the fermentation broth could increase the abundance of Lactobacillales and reduce the production of Gram-negative bacteria, thereby reducing the abnormal increase in bacterial diversity caused by alcohol. In conclusion, we may have discovered a new functional food raw material with great application potential. The above findings indicate that the fermentation broth can actively regulate the intestinal flora and improve liver inflammation. The underlying mechanism might be that the fermentation broth could enhance intestinal permeability and reduce the inflammatory signals and LPS transmitted through the gut-liver axis, thereby reducing the oxidative stress and inflammation of the liver caused by alcohol.

Hepatic Adenosine Triphosphate Reduction Through the Short-Chain Fatty Acids-Peroxisome Proliferator-Activated Receptor γ-Uncoupling Protein 2 Axis Alleviates Immune-Mediated Acute Hepatitis in Inulin-Supplemented Mice

How liver tolerance is disrupted in immune-mediated liver injury is currently unclear. There is also insufficient information available regarding susceptibility, precipitation, escalation, and perpetuation of autoimmune hepatitis. To explore how dietary fiber influences hepatic damage, we applied the concanavalin A (ConA)-induced acute immune-mediated liver injury model in mice fed a diet supplemented with 6.8% inulin, a water-soluble fermentable fiber. Twelve hours after ConA administration, inulin-supplemented diet-fed mice demonstrated significantly alleviated hepatic damage histologically and serologically, with down-regulation of hepatic interferon-γ and tumor necrosis factor and reduced myeloperoxidase (MPO)-producing neutrophil infiltration. Preconditioning with an inulin-supplemented diet for 2 weeks significantly reduced hepatic adenosine triphosphate (ATP) content; suramin, a purinergic P2 receptor antagonist, abolished the protective effect. Of note, the portal plasma derived from mice fed the inulin-supplemented diet significantly alleviated ConA-induced immune-mediated liver injury. Mechanistically, increased portal short-chain fatty acid (SCFA) levels, such as those of acetate and butyrate, by inulin supplementation leads to up-regulation of hepatic γ-type peroxisome proliferator-activated receptor (Pparg) and uncoupling protein 2 (Ucp2), which uncouples mitochondrial ATP synthesis downstream of PPARγ. Pparg down-regulating small interfering RNA cancelled the protective effect of inulin supplementation against MPO-producing neutrophil infiltration and the subsequent immune-mediated liver injury, suggesting that the SCFA-PPARγ-UCP2 axis plays a key role in the protective effect by inulin supplementation. Moreover, significant changes in the gut microbiota, including increased operational taxonomic units in genera Akkermansia and Allobaculum, also characterized the protective effect of the inulin-supplemented diet. Conclusion: There is a possible unraveled etiopathophysiological link between the maintenance of liver tolerance and dietary fiber. The SCFA-PPARγ-UCP2 axis may provide therapeutic targets for immune-mediated liver injury in the future.

Vagus nerve-mediated intestinal immune regulation: therapeutic implications for inflammatory bowel diseases

The pathophysiology of inflammatory bowel disease (IBD) involves immunological, genetic and environmental factors. Through its ability to sense environmental stimuli, the autonomic nervous system plays a key role in the development and persistence of IBD. The vagus nerve (VN), which contains sensory and motor neurons, travels throughout the body to innervate the gut and other visceral organs in the thoracic and abdominopelvic cavities. Recent studies show that the VN has anti-inflammatory effects via the release of acetylcholine, in what is known as the cholinergic anti-inflammatory pathway (CAIP). In the gut immune system, the CAIP is proposed to be activated directly by signals from the gut and indirectly by signals from the liver, which receives gut-derived bioactive substances via the portal vein and senses the status of the gut. The gut-brain axis and liver-brain-gut reflex arc regulate a wide variety of peripheral immune cells to maintain homeostasis in the gut. Therefore, targeting the neural reflex by methods such as VN stimulation is now under investigation for suppressing intestinal inflammation associated with IBD. In this review, we describe the role of the VN in the regulation of intestinal immunity, and we discuss novel therapeutic approaches for IBD that target neuroimmune interactions.

Lactobacillus acidophilus LA14 Alleviates Liver Injury

Although the probiotic Lactobacillus acidophilus LA14 is used worldwide, its effect on liver diseases remains unelucidated. Here, 32 rats were divided into four groups, gavaged with L. acidophilus LA14 (3 × 10⁹ CFU) or phosphate-buffered saline for 7 days, and then intraperitoneally injected with d-galactosamine or saline. After 24 h, blood, liver, ileum, and feces samples were collected for liver injury, inflammation, intestinal barrier, gut microbiota, metabolome, and transcriptome analyses. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bile acids; mitigated the histological injury to the liver and gut; and suppressed the inflammatory cytokines macrophage inflammatory protein 1α (MIP-1α), MIP-3α, and MCP-1. L. acidophilus LA14 also ameliorated the d-galactosamine-induced dysbiosis of the gut microbiota and metabolism, such as the enrichment of Bacteroides sp. strain dnLKV3 and the depletion of Streptococcus, butanoic acid, and N-acetyl-d-glucosamine. The underlying mechanism of L. acidophilus LA14 included prevention of not only the d-galactosamine-induced upregulation of infection- and tumor-related pathways but also the d-galactosamine-induced downregulation of antioxidation-related pathways during this process, as reflected by the liver transcriptome and proteome analyses. Furthermore, the administration of L. acidophilus LA14 to healthy rats did not alter the tested liver indicators but significantly enriched the beneficial Lactobacillus and Bifidobacterium species, promoted metabolism and regulated pathways to improve immunity. The ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

IMPORTANCE The probiotic Lactobacillus acidophilus LA14 is widely used, but its effect on liver diseases has not been elucidated. We explored the protective effect of L. acidophilus LA14 on the liver using rats with d-galactosamine-induced liver injury. Pretreatment with L. acidophilus LA14 alleviated the d-galactosamine-induced elevation of serum ALT, AST, ALP, and bile acids, mitigated the histological injury to the liver and gut, and suppressed the inflammatory cytokines MIP-1α, MIP-3α, and MCP-1. These effects were correlated with the modulations of the gut microbiome, metabolome, and hepatic gene expression induced by L. acidophilus LA14. Moreover, the ability of L. acidophilus LA14 to alleviate liver injury was further confirmed with an acetaminophen-induced mouse model. These results might provide a reference for future studies on the application of L. acidophilus LA14 for the prevention of liver injury.

Probiotics in microbiome ecological balance providing a therapeutic window against cancer

The gut microbiota composition and dietary factors in our food along with the use of prebiotics and probiotics play an important role in the maintenance of human health. A well-balanced gut microbial population is necessary for the host and the microbiota to coexist in a mutually beneficial relationship maintaining homeostasis. Considering the potential of modern technological tools, it is possible nowadays to engineer prebiotic bacteria having a positive influence on the microbiome on one hand while on the other one may have the ease to get rid of the pathogenic proinflammatory microbes or elements causing dysbiosis. Past studies have seen that in cancer there is a loss of inter-microbial relationship cum interactions within microbiota members, the metabolic products produced by them and the host immune system in a microbial ecosystem, leading to dysbiosis. Current review highlights the importance of probiotics in the management of cancer by bringing together majority of the studies together at a single platform and moreover, stresses upon the need to maintain eubiosis in order to evade and inhibit the progression of cancer. Continuous expansion in knowledge about probiotics, their effect on various cancers and the underlying mechanism of action has raised the global scientific interest towards their possible use against different cancers. Furthermore, the article emphasizes upon the need to explore newer therapeutic targets comprising of the microbiome which could further pave the way to the concept of personalized medicines for various kinds of malignancies so as to derive maximum benefits of a treatment modality and to preserve the microbial homeostasis.

Cichorium pumilum Jacq Extract Inhibits LPS-Induced Inflammation via MAPK Signaling Pathway and Protects Rats From Hepatic Fibrosis Caused by Abnormalities in the Gut-Liver Axis

The development of liver fibrosis is closely related to the gut microbiota, and the "gut-liver axis" is the most important connection between the two. ethyl acetate extract of Cichorium pumilum Jacq (CGEA) is an herbal extract consisting mainly of sesquiterpenoids. The anti-inflammatory and hepatoprotective effects of CGEA have been reported, but the anti-fibrotic effects of CGEA via intestinal microbes and the "gut-liver axis" cycle have rarely been reported. In this study, we observed that CGEA not only directly attenuated inflammatory factor levels in inflamed mice, but also attenuated liver inflammation as well as liver fibrosis degeneration in rats with liver fibrosis caused by colitis. We observed in vitro that CGEA significantly promoted the growth of Bifidobacterium adolescentis. Similarly, fecal 16S rDNA sequencing of liver fibrosis rats showed that CGEA intervention significantly altered the composition of the intestinal microbiota of liver fibrosis rats. CGEA increased the abundance of intestinal microbiota, specifically, CGEA increased the ratio of Firmicutes to Bacteroidetes, CGEA could significantly increase the levels of Ruminococcus. In addition, CGEA intervention significantly protected intestinal mucosal tissues and improved intestinal barrier function in rats. Lactucin is the main sesquiterpenoid in CGEA, and HPLC results showed its content in CGEA was up to 6%. Lactucin has been reported to have significant anti-inflammatory activity, and in this study, we found that Lactucin decreased p38 kinases (p38), phosphorylation of the extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) protein phosphorylation in lipopolysaccharide (LPS)-activated RAW264.7 cells, thereby reducing mRNA expression and protein expression of pro-inflammatory factors inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and inhibiting the release of inflammatory factors interleukin (IL)-6 and nitric oxide (NO), exerting anti-inflammatory effects. In summary, the prevention of liver fibrosis caused by intestinal inflammation by CGEA may be achieved by regulating the intestinal microbiota and restoring the intestinal barrier thereby improving the "gut-liver axis" circulation, reducing liver inflammation, and ultimately alleviating liver fibrosis. Notably, the direct anti-inflammatory effect of CGEA may be due to its content of Lactucin, which can exert anti-inflammatory effects by inhibiting the phosphorylation of Mitogen-activated protein kinase (MAPK) and Akt signaling pathways.

Chlamydia overcomes multiple gastrointestinal barriers to achieve long-lasting colonization

Chlamydia trachomatis (CT) is frequently detected in the human gastrointestinal (GI) tract despite its leading role in sexually transmitted bacterial infections in the genital tract. Chlamydia muridarum (CM), a model pathogen for investigating CT pathogenesis in the genital tract, can also colonize the mouse GI tract for long periods. Genital-tract mutants of CM no longer colonize the GI tract. The mutants lacking plasmid functions are more defective in colonizing the upper GI tract while certain chromosomal gene-deficient mutants are more defective in the lower GI tract, suggesting that Chlamydia may use the plasmid for promoting its spread to the large intestine while using the chromosome-encoded factors for maintaining its colonization in the large intestine. The plasmid-encoded Pgp3 is critical for Chlamydia to resist the acid barrier in the stomach and to overcome a CD4⁺ T cell barrier in the small intestine. On reaching the large intestine, Pgp3 is no longer required. Instead, the chromosome-encoded open reading frames TC0237/TC0668 become essential for Chlamydia to evade the group 3-like innate lymphoid cell-secreted interferon (IFN)γ in the large intestine. These findings are important for exploring the medical significance of chlamydial colonization in the gut and for understanding the mechanisms of chlamydial pathogenicity in the genital tract.

Novel Immune Subsets and Related Cytokines: Emerging Players in the Progression of Liver Fibrosis

Liver fibrosis is a pathological process caused by persistent chronic injury of the liver. Kupffer cells, natural killer (NK) cells, NKT cells, and dendritic cells (DCs), which are in close contact with T and B cells, serve to bridge innate and adaptive immunity in the liver. Meanwhile, an imbalanced inflammatory response constitutes a challenge in liver disease. The dichotomous roles of novel immune cells, including T helper 17 (Th17), regulatory T cells (Tregs), mucosa-associated invariant T cells (MAIT), and innate lymphoid cells (ILCs) in liver fibrosis have gradually been revealed. These cells not only induce damage during liver fibrosis but also promote tissue repair. Hence, immune cells have unique, and often opposing, roles during the various stages of fibrosis. Due to this heterogeneity, the treatment, or reversal of fibrosis through the target of immune cells have attracted much attention. Moreover, activation of hepatic stellate cells (HSCs) constitutes the core of fibrosis. This activation is regulated by various immune mediators, including Th17, Th22, and Th9, MAIT, ILCs, and γδ T cells, as well as their related cytokines. Thus, liver fibrosis results from the complex interaction of these immune mediators, thereby complicating the ability to elucidate the mechanisms of action elicited by each cell type. Future developments in biotechnology will certainly aid in this feat to inform the design of novel therapeutic targets. Therefore, the aim of this review was to summarize the role of specific immune cells in liver fibrosis, as well as biomarkers and treatment methods related to these cells.

S-Layer From Lactobacillus brevis Modulates Antigen-Presenting Cell Functions via the Mincle-Syk-Card9 Axis

C-type lectin receptors (CLRs) are pattern recognition receptors that are crucial in the innate immune response. The gastrointestinal tract contributes significantly to the maintenance of immune homeostasis; it is the shelter for billions of microorganisms including many genera of Lactobacillus sp. Previously, it was shown that host-CLR interactions with gut microbiota play a crucial role in this context. The Macrophage-inducible C-type lectin (Mincle) is a Syk-coupled CLR that contributes to sensing of mucosa-associated commensals. In this study, we identified Mincle as a receptor for the Surface (S)-layer of the probiotic bacteria Lactobacillus brevis modulating GM-CSF bone marrow-derived cells (BMDCs) functions. We found that the S-layer/Mincle interaction led to a balanced cytokine response in BMDCs by triggering the release of both pro- and anti-inflammatory cytokines. In contrast, BMDCs derived from Mincle^−/−, CARD9^−/− or conditional Syk^−/− mice failed to maintain this balance, thus leading to an increased production of the pro-inflammatory cytokines TNF and IL-6, whereas the levels of the anti-inflammatory cytokines IL-10 and TGF-β were markedly decreased. Importantly, this was accompanied by an altered CD4⁺ T cell priming capacity of Mincle^−/− BMDCs resulting in an increased CD4⁺ T cell IFN-γ production upon stimulation with L. brevis S-layer. Our results contribute to the understanding of how commensal bacteria regulate antigen-presenting cell (APC) functions and highlight the importance of the Mincle/Syk/Card9 axis in APCs as a key factor in host-microbiota interactions.

Host miRNA-21 promotes liver dysfunction by targeting small intestinal Lactobacillus in mice

New evidence shows that host-microbiota crosstalk can be modulated via endogenous miRNAs. We have previously reported that miR-21 ablation protects against liver injury in cholestasis. In this study, we investigated the role of miR-21 in modulating the gut microbiota during cholestasis and its effects in liver dysfunction. Mice lacking miR-21 had reduced liver damage and were protected against small intestinal injury as well as from gut microbiota dysbiosis when subjected to bile duct ligation surgery. The unique microbiota profile of miR-21KO mice was characterized by an increase in Lactobacillus, a key microbiome genus for gut homeostasis. Interestingly, in vitro incubation of synthetic miR-21 directly reduced Lactobacillus load. Moreover, supplementation with Lactobacillus reuteri revealed reduced liver fibrosis in acute bile duct-ligated mice, mimicking the protective effects in miR-21 knockout mice. D-lactate, a main product of Lactobacillus, regulates gut homeostasis that may link with reduced liver fibrosis. Altogether, our results demonstrate that miR-21 promotes liver dysfunction through direct modulation of the gut microbiota and highlight the potential therapeutic effects of Lactobacillus supplementation in gut and liver homeostasis.

Protective effect of Lactobacillus salivarius Li01 on thioacetamide-induced acute liver injury and hyperammonaemia

The gut microbiota plays pivotal roles in liver disease onset and progression. The protective effects of Lactobacillus salivarius Li01 on liver diseases have been reported. In this study, we aimed to detect the protective effect of L. salivarius Li01 on thioacetamide (TAA)-induced acute liver injury and hyperammonaemia. C57BL/6 mice were separated into three groups and given a gavage of L. salivarius Li01 or phosphate-buffered saline for 7 days. Acute liver injury and hyperammonaemia were induced with an intraperitoneal TAA injection. L. salivarius Li01 decreased mortality and serum transaminase levels and improved histological liver damage caused by TAA. Serum inflammatory cytokine and chemokine and lipopolysaccharide-binding protein (LBP) concentrations, nuclear factor κB (NFκB) pathway activation and macrophage and neutrophil infiltration into the liver were significantly alleviated by L. salivarius Li01. L. salivarius Li01 also reinforced gut barrier and reshaped the perturbed gut microbiota by upregulating Bacteroidetes and Akkermansia richness and downregulating Proteobacteria, Ruminococcaceae_UCG_014 and Helicobacter richness. Plasma and faecal ammonia levels declined noticeably in the Li01 group, accompanied by improvements in cognitive function, neuro-inflammation and relative brain-derived neurotrophic factor (BDNF) gene expression. Our results indicated that L. salivarius Li01 could be considered a potential probiotic in acute liver injury and hepatic encephalopathy (HE).

Hepatic Autophagy Deficiency Remodels Gut Microbiota for Adaptive Protection via FGF15-FGFR4 Signaling

BACKGROUND & AIMS

The functions of the liver and the intestine are closely tied in both physiological and pathologic conditions. The gut microbiota (GM) often cause deleterious effects during hepatic pathogenesis. Autophagy is essential for liver homeostasis, but the impact of hepatic autophagy function on liver-gut interaction remains unknown. Here we investigated the effect of hepatic autophagy deficiency (Atg5Δhep) on GM and in turn the effect of GM on the liver pathology.

METHODS

Fecal microbiota were analyzed by 16S sequencing. Antibiotics were used to modulate GM. Cholestyramine was used to reduce the enterohepatic bile acid (BA) level. The functional role of fibroblast growth factor 15 (FGF15) and ileal farnesoid X receptor (FXR) was examined in mice overexpressing FGF15 gene or in mice given a fibroblast growth factor receptor-4 (FGFR4) inhibitor.

RESULTS

Atg5Δhep causes liver injury and alterations of intestinal BA composition, with a lower proportion of tauro-conjugated BAs and a higher proportion of unconjugated BAs. The composition of GM is significantly changed with an increase in BA-metabolizing bacteria, leading to an increased expression of ileal FGF15 driven by FXR that has a higher affinity to unconjugated BAs. Notably, antibiotics or cholestyramine treatment decreased FGF15 expression and exacerbated liver injury. Consistently, inhibition of FGF15 signaling in the liver enhances liver injury.

CONCLUSIONS

Deficiency of autophagy function in the liver can affect intestinal environment, leading to gut dysbiosis. Surprisingly, such changes provide an adaptive protection against the liver injury through the FGF15-FGFR4 signaling. Antibiotics use in the condition of liver injury may thus have unexpected adverse consequences via the gut-liver axis.

Indian National Association for the Study of Liver Consensus Statement on Acute Liver Failure (Part-2): Management of Acute Liver Failure

Acute liver failure (ALF) is not an uncommon complication of a common disease such as acute hepatitis. Viral hepatitis followed by antituberculosis drug-induced hepatotoxicity are the commonest causes of ALF in India. Clinically, such patients present with appearance of jaundice, encephalopathy, and coagulopathy. Hepatic encephalopathy (HE) and cerebral edema are central and most important clinical event in the course of ALF, followed by superadded infections, and determine the outcome in these patients. The pathogenesis of encephalopathy and cerebral edema in ALF is unique and multifactorial. Ammonia plays a crucial role in the pathogenesis, and several therapies aim to correct this abnormality. The role of newer ammonia-lowering agents is still evolving. These patients are best managed at a tertiary care hospital with facility for liver transplantation (LT). Aggressive intensive medical management has been documented to salvage a substantial proportion of patients. In those with poor prognostic factors, LT is the only effective therapy that has been shown to improve survival. However, recognizing suitable patients with poor prognosis has remained a challenge. Close monitoring, early identification and treatment of complications, and couseling for transplant form the first-line approach to manage such patients. Recent research shows that use of dynamic prognostic models is better for selecting patients undergoing liver transplantation and timely transplant can save life of patients with ALF with poor prognostic factors.

Cyclophosphamide Increases Lactobacillus in the Intestinal Microbiota in Chickens

Poultry production is a very intensive industry. Due to the substantial number of animals being raised by any one producer, even small variations in productivity lead to important economical outcomes. The intestinal microbiota of birds is under intense scrutiny by the immune system. Therefore, it is a factor that can influence the states of health and disease of the host. The body of knowledge on the interactions between these systems is gradually bringing practical guidance for poultry production.

Recent data in humans indicate that immunosuppression is correlated with shifts in the intestinal microbiota. However, the relationship between immunosuppression and intestinal microbiota has not been studied in chickens. Thus, we investigated the correlations between immune cells and intestinal microbiota by massive parallel sequencing of the 16S rRNA bacterial gene in chickens immunosuppressed with cyclophosphamide. The results showed correlations between peripheral immune cells and intestinal microbiota. Surprisingly, an increase in the abundance of intestinal Lactobacillus in the immunosuppressed chickens was observed. These birds also had low intestinal IgA antibody levels among other alterations in the microbiota. These shifts indicate a role of the immunity system in controlling the microbiota of birds.

IMPORTANCE Poultry production is a very intensive industry. Due to the substantial number of animals being raised by any one producer, even small variations in productivity lead to important economical outcomes. The intestinal microbiota of birds is under intense scrutiny by the immune system. Therefore, it is a factor that can influence the states of health and disease of the host. The body of knowledge on the interactions between these systems is gradually bringing practical guidance for poultry production.

Beneficial effects of LRP6-CRISPR on prevention of alcohol-related liver injury surpassed fecal microbiota transplant in a rat model

Alcohol intake can modify gut microbiota composition, increase gut permeability, and promote liver fibrogenesis. LRP6 is a signal transmembrane protein and a co-receptor for the canonical Wnt signaling pathway. This study compared the curative effect of LRP6-CRISPR on alcohol-related liver injury with that of traditional fecal microbiota transplant (FMT) and investigated the alteration of the gut microbiome following the treatment. A rat model of alcohol-related liver injury was established and injected with lentiviral vectors expressing LRP6-CRISPR or administered with fecal filtrate from healthy rats, with healthy rat served as the control. Liver tissues of rats were examined by HE staining, Sirius staining, and Oil red O staining, respectively. The expression of LRP6 and fibrosis biomarkers were tested by PCR. The fecal sample of rats was collected and examined by 16S rRNA sequencing. Our data indicated that LRP6-CRISPR was more efficient in the prevention of alcohol-related liver injury than FMT. Microbiome analysis showed that alcohol-related liver injury related to gut microbiota dysbiosis, while treatment with LRP6-CRISPR or FMT increased gut microflora diversity and improved gut symbiosis. Further, bacteria specific to the disease stages were identified. Genera Romboutsia, Escherichia-Shigella, Pseudomonas, Turicibacter, and Helicobacter were prevalent in the intestine of rats with alcohol-related liver injury, while the domination of Lactobacillus was found in rats treated with LRP6-CRISPR or FMT. Besides, Lactobacillus and genera belonging to family Lachnospiraceae, Bacteroidales S24-7 group, and Ruminococcaceae were enriched in healthy rats. LRP6-CRISPR and FMT have beneficial effects on the prevention of alcohol-related liver injury, and correspondently, both treatments altered the disrupted gut microflora to a healthy one.

The liver-brain-gut neural arc maintains the Treg cell niche in the gut

Recent clinical and experimental evidence has evoked the concept of the gut-brain axis to explain mutual interactions between the central nervous system and gut microbiota that are closely associated with the bidirectional effects of inflammatory bowel disease and central nervous system disorders^1-4. Despite recent advances in our understanding of neuroimmune interactions, it remains unclear how the gut and brain communicate to maintain gut immune homeostasis, including in the induction and maintenance of peripheral regulatory T cells (pT_reg cells), and what environmental cues prompt the host to protect itself from development of inflammatory bowel diseases. Here we report a liver-brain-gut neural arc that ensures the proper differentiation and maintenance of pT_reg cells in the gut. The hepatic vagal sensory afferent nerves are responsible for indirectly sensing the gut microenvironment and relaying the sensory inputs to the nucleus tractus solitarius of the brainstem, and ultimately to the vagal parasympathetic nerves and enteric neurons. Surgical and chemical perturbation of the vagal sensory afferents at the hepatic afferent level reduced the abundance of colonic pT_reg cells; this was attributed to decreased aldehyde dehydrogenase (ALDH) expression and retinoic acid synthesis by intestinal antigen-presenting cells. Activation of muscarinic acetylcholine receptors directly induced ALDH gene expression in both human and mouse colonic antigen-presenting cells, whereas genetic ablation of these receptors abolished the stimulation of antigen-presenting cells in vitro. Disruption of left vagal sensory afferents from the liver to the brainstem in mouse models of colitis reduced the colonic pT_reg cell pool, resulting in increased susceptibility to colitis. These results demonstrate that the novel vago-vagal liver-brain-gut reflex arc controls the number of pT_reg cells and maintains gut homeostasis. Intervention in this autonomic feedback feedforward system could help in the development of therapeutic strategies to treat or prevent immunological disorders of the gut.

[Gut microbiota-an important contributor to liver diseases]

Gut microbiota constitute a complicated but manifold ecosystem, in which specific symbiotic relationships are formed among various bacteria. To maintain a steady state, the gastrointestinal tract and the liver form a close anatomical and functional two-way, interconnected network through the portal circulation. "Gut-liver axis" plays a key role in the pathogenesis of liver diseases. Accumulating evidence indicates that gut microbiota can influence the liver pathophysiology directly or indirectly via a variety of signal pathways. In a pathological state where an ecological imbalance occurs at the compositional and functional levels, gut microbes would interact with the host immune system and other type of cells to cause liver steatosis, inflammation and fibrosis, which in turn give rise to the development of such liver diseases as alcoholic liver disease, nonalcoholic fatty liver disease, primary sclerosing cholangitis, and acute liver failure, to name a few. Studies have shown that microorganisms, such as prebiotics and probiotics, can improve the prognosis of certain diseases, which open a new era of treating liver diseases with bacteria. There are many unknowns and hidden values in the gut microbiome. To explore the pathophysiological mechanism of various complex diseases and develop scientific and effective clinical treatment strategies, efforts should be made to obtain insights into how certain intestinal microbiota participates in the occurrence and progression of liver diseases. As the connection between gut microbiota and liver diseases at both the acute and chronic phases was not elaborated in previously published review articles, herein we discuss the association between gut microbiota and both acute and chronic liver injury. The anatomical structure of the liver enables it to form a close network with the gut microbiota, which is an important mediator in the regulation of the hepatic physiological and pathological functions.

Friend or foe? Lactobacillus in the context of autoimmune disease

Over the last decade, the interplay between the gut microbiota, the consortium of intestinal microbes that colonizes intestinal mucosal barriers, and its host immune system has been increasingly better understood. Disruption of the delicate balance between beneficial and pathogenic commensals, known as dysbiosis, contributes to a variety of chronic immunologic and metabolic diseases. Complicating this paradigm are bacterial strains that can operate paradoxically both as instigators and attenuators of inflammatory responses, depending on host background. Here, we review the role of several strains in the genus Lactobacillus within the context of autoimmune and other chronic disorders with a predominant focus on L. reuteri. While strains within this species have been shown to provide immune health benefits, they have also been demonstrated to act as a pathobiont in autoimmune-prone hosts. Beneficial functions in healthy hosts include competing with pathogenic microbes, promoting regulatory T cell development, and protecting the integrity of the gut barrier. On the other hand, certain strains can also break through a dysfunctional gut barrier, colonize internal tissues such as the spleen or liver and promote inflammatory responses in host tissues that lead to autoimmune disease. This review summarizes the manifold roles that these commensals play in the context of health and disease.

Evasion of Innate Lymphoid Cell-Regulated Gamma Interferon Responses by Chlamydia muridarum To Achieve Long-Lasting Colonization in Mouse Colon

Revealing the mechanisms by which bacteria establish long-lasting colonization in the gastrointestinal tract is an area of intensive investigation. The obligate intracellular bacterium Chlamydia is known to colonize mouse colon for long periods. A colonization-deficient mutant strain of this intracellular bacterium is able to regain long-lasting colonization in gamma interferon (IFN-γ) knockout mice following intracolon inoculation. We now report that mice deficient in conventional T lymphocytes or recombination-activating gene (Rag) failed to show rescue of mutant colonization. Nevertheless, antibody depletion of IFN-γ or genetic deletion of interleukin 2 (IL-2) receptor common gamma chain in Rag-deficient mice did rescue mutant colonization. These observations suggest that colonic IFN-γ, responsible for inhibiting the intracellular bacterial mutant, is produced by innate lymphoid cells (ILCs). Consistently, depletion of NK1.1⁺ cells in Rag-deficient mice both prevented IFN-γ production and rescued mutant colonization. Furthermore, mice deficient in transcriptional factor RORγt, but not chemokine receptor CCR6, showed full rescue of the long-lasting colonization of the mutant, indicating a role for group 3-like ILCs. However, the inhibitory function of the responsible group 3-like ILCs was not dependent on the natural killer cell receptor (NCR1), since NCR1-deficient mice still inhibited mutant colonization. Consistently, mice deficient in the transcriptional factor T-bet only delayed the clearance of the bacterial mutant without fully rescuing the long-lasting colonization of the mutant. Thus, we have demonstrated that the obligate intracellular bacterium Chlamydia maintains its long-lasting colonization in the colon by evading IFN-γ from group 3-like ILCs.

Protective effects of specific cannabinoid receptor 2 agonist GW405833 on concanavalin A-induced acute liver injury in mice

Cannabinoid receptor 2 (CB2R) is highly expressed in immune cells and plays an important role in regulating immune responses. In the current study, we investigated the effects of GW405833 (GW), a specific CB2R agonist, on acute liver injury induced by concanavalin A (Con A). In animal experiments, acute liver injury was induced in mice by injection of Con A (20 mg/kg, i.v.). The mice were treated with GW (20 mg/kg, i.p., 30 min after Con A injection) or GW plus the selective CB2R antagonist AM630 (2 mg/kg, i.p., 15 min after Con A injection). We found that Con A caused severe acute liver injury evidenced by significantly increased serum aminotransferase levels, massive hepatocyte apoptosis, and necrosis, as well as lymphocyte infiltration in liver tissues. Treatment with GW significantly ameliorated Con A-induced pathological injury in liver tissue, decreased serum aminotransferase levels, and decreased hepatocyte apoptosis. The therapeutic effects of GW were prevented by AM630. In cell experiments, we showed that CB2Rs were highly expressed in Jurkat T cells, but little expression in L02 liver cells. Treatment with GW (10-40 μg/mL) dose-dependently decreased the viability of Jurkat T cells and induced cell apoptosis, which was reversed by AM630. In the coculture of Jurkat T cells with L02 liver cells, GW dose-dependently protected L02 cells from apoptosis induced by Con A (5 μg/mL). The protective effect of GW was reversed by AM630 (1 μg/mL). Our results suggest that GW protects against Con A-induced acute liver injury in mice by inhibiting Jurkat T-cell proliferation through the CB2Rs.

Lactobacillus reuteri ZJ617 Culture Supernatant Attenuates Acute Liver Injury Induced in Mice by Lipopolysaccharide

BACKGROUND

Lactobacillus rhamnosus GG culture supernatant (LGGs) promotes intestinal integrity and ameliorates acute liver injury induced by alcohol in mice.

OBJECTIVES

The aim of this study was to investigate the protective effects and molecular mechanisms of Lactobacillus reuteri ZJ617 culture supernatant (ZJ617s) on acute liver injury induced by lipopolysaccharide (LPS) in mice.

METHODS

Male C57BL/6 mice (20 ± 2 g, 8 wk old) were randomly divided into 4 groups (6 mice/group): oral inoculation with phosphate-buffered saline (control), intraperitoneal injection of LPS (10 mg/kg body weight) (LPS), oral inoculation with ZJ617s 2 wk before intraperitoneal injection of LPS (ZJ617s + LPS), or oral inoculation with LGGs 2 wk before intraperitoneal injection of LPS (LGGs + LPS). Systemic inflammation, intestinal integrity, biomarkers of hepatic function, autophagy, and apoptosis signals in the liver were determined.

RESULTS

Twenty-four hours after LPS injection, the activities of serum alanine transaminase and aspartate transaminase were 32.2% and 30.3% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05). The ZJ617s + LPS group exhibited higher intestinal expression of claudin 3 (62.5%), occludin (60.1%), and zonula occludens 1 (60.5%) compared with the LPS group (P < 0.05). The concentrations of hepatic interleukin-6 and tumor necrosis factor-α were 21.4% and 27.3% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05). However, the concentration of interleukin-10 was 22.2% higher in the ZJ617s + LPS group. LPS increased the expression of Toll-like receptor 4 (TLR4; by 50.5%), phosphorylation p38 mitogen-activated protein kinase (p38MAPK; by 57.1%), extracellular signal-regulated kinase (by 77.8%), c-Jun N-terminal kinase (by 42.9%), and nuclear factor-κB (NF-κB; by 36.0%) compared with the control group. Supplementation with ZJ617s or LGGs ameliorated these effects (P < 0.05). Moreover, the hepatic expression of active caspase-3 and microtubule-associated protein 1 light chain 3 II was 23.8% and 28.6% lower in the ZJ617s + LPS group compared with the LPS group, respectively (P < 0.05).

CONCLUSIONS

ZJ617s exerts beneficial effects on the mouse liver through suppression of hepatic TLR4/MAPK/NF-κB activation, apoptosis, and autophagy. This trial was registered at Zhejiang University (http://www.lac.zju.edu.cn) as NO.ZJU20170529.