Mouse Intestine Research Articles

Combined BPA and DIBP Exposure Induced Intestinal Mucosal Barrier Impairment Through the Notch Pathway and Gut Microbiota Dysbiosis in Mice

Bisphenol A (BPA) and diisobutyl (DIBP) phthalate are widely used as typical plasticizers in food packaging. Plasticizers can be released from polymers, migrate into food, and be ingested by humans, leading to various health problems. However, little research has investigated the combined toxicity of BPA and DIBP, particularly their intestinal toxicity. Our goal is to analyse the combined toxicity of BPA (50 mg/kg) and DIBP (500 mg/kg) on the intestines of KM mice. Additionally, we tried to find natural products that can inhibit or prevent the combined toxicity of BPA and DIBP. The results indicated that the combination of BPA and DIBP exposure resulted in a reduction of beneficial flora, an increase in D-Lac levels (136 ± 14 μmol/L), an increase in intestinal permeability, activation of the notch pathway, and a decline in intestinal stem cells (ISCs) to goblet cells, compared to single-exposure sources. Nevertheless, Rubus chingii Hu phenolic extract (RHPE) (200, 400 and 600 mg/kg) ameliorated the BPA and DIBP-induced intestinal microbiota disruption and intestinal mucosal barrier impairment by inhibiting the overactivation of the notch pathway. The results of this study highlight the potential risks to human health posed by the combination of BPA and DIBP and may help explain the potential pathways of enterotoxicity caused by combined ingestion.

Short-chain fatty acid metabolites propionate and butyrate are unique epigenetic regulatory elements linking diet, metabolism and gene expression.

The short-chain fatty acids (SCFAs) propionate and butyrate have beneficial health effects, are produced in large amounts by microbial metabolism and have been identified as unique acyl lysine histone marks. To better understand the function of these modifications, we used chromatin immunoprecipitation followed by sequencing to map the genome-wide location of four short-chain acyl histone marks, H3K18pr, H3K18bu, H4K12pr and H4K12bu, in treated and untreated colorectal cancer (CRC) and normal cells as well as in mouse intestines in vivo. We correlate these marks with open chromatin regions and gene expression to access the function of the target regions. Our data demonstrate that propionate and butyrate bind and act as promoters of genes involved in growth, differentiation and ion transport. We propose a mechanism involving direct modification of specific genomic regions by SCFAs resulting in increased chromatin accessibility and, in the case of butyrate, opposing effects on the proliferation of normal versus CRC cells.

An Emerging Toolkit of Ho3+ Sensitized Lanthanide Nanocrystals with NIR-II Excitation and Emission for in Vivo Bioimaging.

Optical imaging in the second near-infrared window (NIR-II, 1000-1700 nm) holds great promise for biomedical detection due to reduced tissue scattering and autofluorescence. However, the rational design of NIR-II probes with superior excitation wavelengths to balance the effects of tissue scattering and water absorption remains a great challenge. To address this issue, here we developed a series of Ho3+-sensitized lanthanide (Ln) nanocrystals (NaYF4: Ho, Ln@NaYF4) excited at 1143 nm, featuring tunable emissions ranging from 1000 to 2200 nm for in vivo bioimaging. Precise core-shell engineering (β-NaYF4: Ho@NaYF4: Ln@NaYF4 and β-NaYF4: Ho/Yb@NaYbF4@NaYbF4: Ln@NaYF4) further endows the Ho3+-sensitized system with the capability of energy migration within interfaces, enabling more abundant visible and NIR-II emissions that are unattainable in co-doped structures due to detrimental cross relaxation. Tissue phantom studies demonstrated the superior tissue penetration ability of 1143 photons, especially in imaging experiments through the highly photon-scattering skull, where the fluorescence transmittance of 1143 nm excited nanocrystals was 15% and 10% higher than that of the conventional 808 and 980 excitation, respectively. By leveraging these Ho3+-sensitized nanomaterials with multiemission characteristics and well-selected lanthanide nanomaterials with crosstalk-free excitation, we achieved six-channel NIR-II in vivo imaging, enabling the simultaneous visualization of blood vessels, liver, spleen, stomach, intestine, subcutaneous tumors, and lymph nodes in mice. Our research provides new insights into the design of lanthanide nanocrystals with NIR-II excitation and emission and highlights the potential of these materials in in vivo multichannel detection.

Protection induced by recombinant vaccinia virus targeting the ROP4 of Toxoplasma gondii in mice.

Toxoplasmosis is a parasitic disease affecting a significant portion of the global population, whose etiology can be attributed to the protozoan organism Toxoplasma gondii. Despite its public health importance, an efficacious vaccine to prevent human toxoplasmosis remains unavailable. To this end, we designed an experimental toxoplasmosis vaccine using recombinant vaccinia virus vectors (rVacv) expressing the T. gondii rhoptry protein 4 (ROP4) antigen and evaluated its efficacy in a murine model. Intranasal vaccination with ROP4-rVacvs induced parasite-specific serum antibody responses as early as 3 weeks post-immunization, with subsequent immunizations elevating antibody responses to a greater extent. When challenged with T. gondii ME49 strain, significantly enhanced levels of mucosal IgA antibodies were detected in the intestines of immunized mice. Additionally, ROP4-rVacv immunization ensured that T cells and germinal center B cell populations were retained at high levels. These immune responses mitigated the severity of neuroinflammation, reduced tissue cyst formation, and ensured the survival of immunized mice. Our findings indicate that ROP4-rVacv could be a promising toxoplasmosis vaccine candidate.

Assessment of the pathogenicity of Y. enterocolitica B1A isolates from San Luis, Argentina.

Yersinia enterocolitica, a bacterial enteropathogen that produces a variety of clinical manifestations in humans, includes six biotypes (B), called 1A, 1B, 2, 3, 4 and 5 and about 70 serotypes. The biotypes exhibit diverse pathogenic potential; while 1B and 2-5 may show ability to produce clinical symptoms due to the presence of chromosomal and plasmid (pYV) virulence genes, B1A is supposed a non-pathogenic biotype since it lacks pYV plasmid. Therefore, although B1A strains cause diarrhea in humans, their pathogenic potential has not yet been extensively studied. The objective of this study was to assess virulence genetic markers of local Y. enterocolitica B1A strains and determine clonal relationships between isolates. To this, Y. enterocolitica chromosomal virulence markers were evaluated by PCR, Yst enterotoxin activity of culture filtrates in the intestine of suckling mice was tested and PFGE was applied in 24 Y. enterocolitica B1A strains obtained from human feces, foods, animals and environmental samples of our region (isolated among 2000-2014). The detection frequency of virulence chromosomal markers was as follows: fepA [95.8% (23/24)], ystB [91.7% (22/24)], hreP [87.5 % (21/24)], tccC [12.5% (3/24)] and myfA [4.2% (1/24)]. Presence of ystB gene was strongly associated to the Yst activity in suckling mice. By PFGE, B1A strains were divided into 10 genomic patterns (GP). Interestingly, human strains showed 88% similarity when compared to strains of the same serotype from other sources. Our results support the pathogenicity of Y. enterocolitica B1A strains and highlight the valuable impact of the Y. enterocolitica monitoring to prevent and control the spreading of this pathogen in our region.

EGCG protects intestines of mice and pelvic cancer patients against radiation injury via the gut microbiota/D-tagatose/AMPK axis

Background and purposeRadiation-induced intestinal injury (RIII) compromises the clinical utility of pelvic radiotherapy (RT). We aimed to explore the protective effect and underlying mechanism of (−)-epigallocatechin-3-gallate (EGCG) on RIII. Materials and methodsWe evaluated the protective effect of EGCG on intestine in RIII mouse model and pelvic cancer patients, while explored the underlying mechanism through (1) 16S rRNA sequencing, (2) metabolomic profiles, (3) fresh sterile fecal filtrate (SFF) transplantation, and (4) transcriptome sequencing. ResultsEGCG efficiently prevented RIII in mouse, as reflected by improved survival, alleviated intestinal structure damage, promoted intestinal regeneration, and ameliorated gut microbiota dysbiosis. Prophylactic EGCG intervention reduced the severity of RIII in patients receiving pelvic RT. Mechanistically, the protective effect of EGCG could be transferred to other mice by SFF transplantation. EGCG enriched gut microbiota-derived metabolite D-tagatose, and oral administration of D-tagatose reproduced the radio-protective effect of EGCG via activating AMPK. ConclusionOral EGCG may be a promising strategy for preventing RIII clinically, and warrant further investigation in prospective randomized phase III trials.

Phellodendrine inhibits oxidative stress and promotes autophagy by regulating the AMPK/mTOR pathway in burn sepsis-induced intestinal injury

Abstract Intestinal injury is an important complication of burn sepsis with limited therapeutic choices. Phellodendrine is a promising compound for gastrointestinal inflammatory diseases and is extracted from the traditional Chinese medicine phellodendron bark. The study aimed to explore the role of phellodendrine against oxidative stress and autophagy in burn sepsis-induced intestinal injury. A mouse model of burn sepsis model was established by intraperitoneally injecting 10 mg/kg lipopolysaccharide (LPS) to mice burned by boiled water. Phellodendrine (30 mg/kg) was injected into mice in the drug group after scalding and before LPS injection. Hematoxylin and eosin staining was performed to observe histopathological changes in murine small intestines. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed to evaluate intestinal cell apoptosis. Immunofluorescence staining was performed to measure the expression and distribution of autophagy markers, light chain 3II (LC3II) and p62 in intestinal tissues. Oxidative stress indicators were detected using corresponding commercial kits. Protein levels of apoptotic markers, autophagy markers, and factors involved in adenosine monophosphate-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway in intestines were quantified by western blotting. Phellodendrine attenuated bun sepsis-induced intestinal pathological changes. Meanwhile, aggravated cell apoptosis, reduction of antioxidant enzymes, and downregulation of autophagy markers in intestinal tissues of burn sepsis group were all improved by phellodendrine. In addition, phellodendrine activated the phosphorylation (p) of AMPK and inhibited p-mTOR signaling in intestines of burn septic mice. In conclusion, phellodendrine suppresses oxidative stress and activates autophagy in burn sepsis-induced intestinal injury by activating AMPK and inhibiting mTOR signaling.

Effects of orally exposed SiO2 nanoparticles on lipid profiles in gut-liver axis of mice.

Recently we proposed the possibility of orally exposed nanoparticles (NPs) to alter metabolite homeostasis by changing metabolism pathways, in addition to intestinal damages, but relatively few studies investigated the changes of metabolite profiles in multi-organs. This study investigated the influences of orally exposed SiO2 NPs on lipid profiles in gut-liver axis. To this end, we treated mice with 16, 160 or 1600 mg/kg bodyweight SiO2 NPs via intragastric route. After 5 days exposure (once a day), we observed that SiO2 NPs induced minimal pathological changes but increased most of the trace elements. Furthermore, lipid staining was gradually decreased in intestines and livers with the increase of NP levels. Consistently, lipidomics results showed that most of the lipid classes in mouse intestines and livers were decreased following SiO2 NP administration. We further identified the lipid classes significantly decreased in both intestines and livers, such as phosphatidylserine (PS), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE). Only a few lipid classes, such as anandamide, showed opposite trends in these organs. For metabolism pathway, SiO2 NPs suppressed autophagy, showing as a significant decrease of microtubule-associated protein 1 A/1B light chain 3 (LC3) and adipose triglyceride lipase (Atgl), accompanying with an accumulation of P62, in both intestines and livers. However, lysosomal-associated membrane protein 2 (Lamp2) showed different trend, that it was significantly increased in intestines but decreased in livers. Combined, our results indicated that intragastric administration of SiO2 NPs altered trace element balance and lipid profiles, accompanying with a change of autophagic lipolysis proteins, in mouse gut-liver axis.

Bifidobacterium longum subsp. longum relieves loperamide hydrochloride-induced constipation in mice by enhancing bile acid dissociation.

Bifidobacterium species are known for their efficacy in alleviating constipation. This study aimed to compare the constipation-relieving effects of different Bifidobacterium species (Bifidobacterium longum subsp. longum, Bifidobacterium bifidum, Bifidobacterium animalis, Bifidobacterium breve, Bifidobacterium longum subsp. infantis, and Bifidobacterium adolescentis) and to explore the underlying mechanisms from both the bacterial and host perspectives. We evaluated six Bifidobacterium species for their physiological properties, including growth rate, oligosaccharide utilization, osmotic pressure resistance, cell adhesion, and bile acid dissociation capability. Mice with severe constipation induced by loperamide hydrochloride were treated with these bacteria at a density of 109 CFU per mL for 17 days. Gastrointestinal indices such as fecal water content, time to first black stool defecation, and small intestine propulsion rate were measured to assess constipation relief. Microbiome and metabolome (bile acid and tryptophan) analyses were conducted to elucidate the differences in constipation relief among the species. Our results demonstrated that Bifidobacterium longum subsp. longum exhibited superior physiological traits, including rapid growth, extensive oligosaccharide utilization, and high bile salt dissociation capacity. Notably, only Bifidobacterium longum subsp. longum significantly ameliorated constipation symptoms in the mouse model. Furthermore, this strain markedly restored bile acid and short-chain fatty acid levels in the intestines of constipated mice and altered the composition of the intestinal microbiota. These findings suggest that the enhanced efficacy of Bifidobacterium longum subsp. longum in relieving constipation is associated with its ability to modulate intestinal physiology and microbiota structure and metabolism.

Intestinal stem cell-derived extracellular vesicles ameliorate necrotizing enterocolitis injury.

The therapeutic potential of intestinal stem cell-derived extracellular vesicles (ISCs-EVs) in necrotizing enterocolitis (NEC) remains largely unexplored. This research aims to investigate the therapeutic effects of ISCs-EVs on NEC. Lgr5-positive ISCs were screened from the small intestine of mice by flow cytometry, and ISCs-EVs were isolated by density gradient centrifugation. Subsequently, ISCs-EVs were identified through transmission electron microscopy, nanoparticle tracking analysis, and western blotting. Subsequently, we evaluated the efficacy of ISCs-EVs in a mouse model of NEC and found that they enhanced survival (more than 20%), reduced intestinal damage (restore the number of intestinal crypts and decrease the expression of MPO and cleaved-caspase 3 in intestinal tissues), promoted angiogenesis (the mRNA expression of VEGF was increased by approximately 35%), and mitigated inflammation (decreased the level of MUC1, p-NF-κB, IL-6 and TNF-α). Furthermore, in vitro assessments demonstrated that ISCs-EVs reduced apoptosis (P<0.01) and stimulated proliferation (P<0.05) of IEC-6cells, while enhancing mucin secretion in LS174T cells. In summary, our study provides a comprehensive assessment of the therapeutic effects of ISCs-EVs on NEC, using both animal and cell models. This highlights their potential for use in NEC treatment.

Oral Delivery of miR146a Conjugated to Cerium Oxide Nanoparticles Improves an Established T Cell-Mediated Experimental Colitis in Mice.

Background: Dysregulated inflammation and oxidative stress are strongly implicated in the pathogenesis of inflammatory bowel disease. We have developed a novel therapeutic that targets inflammation and oxidative stress. It is comprised of microRNA-146a (miR146a)-loaded cerium oxide nanoparticles (CNPs) (CNP-miR146a). We hypothesized that oral delivery of CNP-miR146a would reduce colonic inflammation in a mouse model of established, chronic, T cell-mediated colitis. Methods: The stability of CNP-miR146a and mucosal delivery was assessed in vitro with simulated gastrointestinal fluid and in vivo after oral gavage by quantitative real-time RT-PCR. The efficacy of orally administered CNP-miR146a was tested in mice with established colitis using the model of adoptive naïve T-cell transfer in recombinant activating gene 2 knockout (Rag2-/-) mice. Measured outcomes included histopathology; CD45+ immune cell infiltration; oxidative DNA damage (tissue 8-hydroxy-2'-deoxyguanosine; 8-OHdG); expression of IL-6 and TNF mRNA and protein, and flow cytometry analysis of lamina propria Th1 and Th17 cell populations. Results: miR146a expression remained stable in simulated gastric and intestinal conditions. miR146a expression increased in the intestines of mice six hours following oral gavage of CNP-miR146a. Oral delivery of CNP-miR146a in mice with colitis was associated with reduced inflammation and oxidative stress in the proximal and distal colons as evidenced by histopathology scoring, reduced immune cell infiltration, reduced IL-6 and TNF expression, and decreased populations of CD4+Tbet+IFNg+ Th1, CD4+RorgT+IL17+ Th17, as well as pathogenic double positive IFNg+IL17+ T cells. Conclusions: CNP-miR146a represents a novel orally available therapeutic with high potential to advance into clinical trials.

Alzheimer's disease-like pathology induced by Porphyromonas gingivalis in middle-aged mice is mediated by NLRP3 inflammasome via the microbiota-gut-brain axis.

Porphyromonas gingivalis (P. gingivalis) has been found to enter the brain and induce inflammation, contributing to Alzheimer's disease (AD). P. gingivalis is also closely linked to gut dysbiosis. However, does P. gingivalis induce AD-like pathology through the microbiota-gut-brain axis? There is limited literature on this topic. To determine the precise causal link among P. gingivalis, intestinal inflammation, and AD-related pathology. 12- to 13-month-old female C57BL/6J mice were subjected to ligature placement and oral administration of P. gingivalis over a 24-week period. Then, cognitive performance was evaluated with behavioral tests, while AD neuropathological changes, neuroinflammation, and intestinal inflammation were assessed through qPCR, immunofluorescence, and western blot, and gut microbiota was analyzed by 16S rRNA. Mice exposed to P. gingivalis showed impaired behavior in open field test, novel object recognition, and Y-maze tests. The bacterium infiltrated their brains, increasing Aβ42, AβPP, and Aβ fragments, promoting tau phosphorylation and microglial activation, and reducing levels of ZO-1, PSD95, SYP, and NeuN proteins. Inflammatory factors like NLRP3, caspase-1, IL-1β, IL-6, and TNF-α were elevated in both brains and intestine, while ZO-1 and occludin levels decreased in intestine. P. gingivalis also altered gut microbial compositions. P. gingivalis induced gut dysbiosis and activated the NLRP3 inflammasome in the intestine and brains of mice. This led to impairment of both the intestinal and brain-blood barriers, triggering neuroinflammation and promoting the progression of AD. These findings highlight the critical role of NLRP3 inflammasome activation in the microbiota-gut-brain axis in the AD-like pathology induced by P. gingivalis.

Probiotic DNA regulates intestinal Th2 polarization by inducing epithelial cells to produce PD-L1.

Th2 polarization is a characteristic feature of many immune diseases; its pathogenesis is still being elucidated. Probiotics have immune regulatory effects. This study is aimed at testing the impact of Lactobacillus rhamnosus (LR) DNA on regulating Th2 polarization and elucidating its underlying mechanism. In this study, ovalbumin plus alum protocol was used to establish the Th2 polarization status in the mouse intestine. Mice received LR-DNA gavage daily for five days. The expression of programmed cell death ligand-1 (PD-L1) in intestinal epithelial cells was assessed using RT-qPCR, enzyme-linked immunosorbent assay, and immunohistochemistry. The results showed that the expression of PD-L1 was detected in mouse intestinal epithelial cells, which was up regulated by LR-DNA gavage daily for 5 days. The expression of PD-L1 was also detected in T84 cells, which could be increased by exposing them to LR-DNA in culture. RNA sequencing results showed that the gene activities of Kdm5a, foxo1 and Pdl1 could be upregulated by LR-DNA in mouse intestinal epithelial cells. The epithelial cell-derived PD-L1 induced the activated Th2 cell apoptosis by interacting with programmed cell death protein-1 (PD-1). Administration of LR-DNA, but not live probiotics, alleviated experimental Th2 polarization in a food allergy mouse model. In conclusion, LR-DNA induces intestinal epithelial cells to produce PD-L1, which induces the activated Th2 cell apoptosis. Administration of LR-DNA mitigated experimental Th2 polarization in the intestine.

Retinoblastoma-Binding Protein 9 Suppresses Intestinal Inflammation and Inflammation-Induced Tumorigenesis in Mice

BACKGROUND & AIMSRetinoblastoma-binding protein 9 (RBBP9) was initially reported as cell cycle regulator via RB/E2F. Accumulating evidence has revealed the importance of RBBP9 in physiological and pathological states including inflammatory disease. However, the functional role of RBBP9 in ulcerative colitis (UC) and colitis-associated cancer (CAC) remains elusive. METHODSHuman samples of UC and CAC were examined by immunohistochemical and bioinformatics analyses. We established dextran sodium sulfate (DSS)-induced colitis, azoxymethane (AOM)/DSS-induced CAC model, and ApcMin/+ sporadic tumor model using wild-type and Rbbp9-/- mice. RNA sequencing was analyzed to identify the phenotype alternation upon Rbbp9 deletion. In addition, genetic and pharmacological inhibition of the Janus kinase (JAK)/signal transducer and activator of transcription 1 (STAT1) pathway was performed. RESULTSThe expression of RBBP9 was reduced in human UC and CAC samples. The loss of RBBP9 enhanced the activation of interferon (IFN)/JAK/STAT1 signaling, resulting in susceptibility to DSS-induced colitis and AOM/DSS-induced CAC tumors by increasing epithelial cell apoptosis and immune activation. An in vitro kinase assay revealed that RBBP9 directly regulated JAK/STAT1 signaling by suppressing STAT1 phosphorylation. A positive feedback loop involving epithelial cell apoptosis, commensal microbiome invasion, and activation of submucosal immune activity was identified in Rbbp9-/- mouse intestines through enhanced JAK/STAT1 signaling in RBBP9-deficient epithelial cells and macrophages. The genetic inhibition of STAT1 or treatment with the JAK/STAT inhibitor reversed epithelial cell apoptosis and mitigated the enhanced susceptibility to DSS-induced colitis in Rbbp9-/- mice. CONCLUSIONSRBBP9 suppresses the intestinal inflammation by negatively regulating JAK/STAT1 signaling pathway.

Fecal Microbiota Transplantation Activity of Floccularia luteovirens Polysaccharides and Their Protective Effect on Cyclophosphamide-Induced Immunosuppression and Intestinal Injury in Mice.

Floccularia luteovirens polysaccharides (FLP1s) have potential biological activities. Our previous study showed that FLP1s positively regulated gut immunity and microbiota. However, it is still unclear whether FLP1s mediate gut microbiota in immunosuppressed mice. This research aims to explore the relationship between FLP1-mediated gut microbes and intestinal immunity in immunosuppressed mice through fecal microbiota transplantation (FMT). The results demonstrated that FLP1s exhibited prebiotic and anti-immunosuppressive effects on CTX-induced immunosuppressed mice. FFLP1 treatment (microbiota transplantation from the fecal sample) remarkably elevated the production of sIgA and secretion of the anti-inflammatory cytokines IL-4, TNF-α, and IFN-γ in the intestine of CTX-treated mice, inducing activation of the MAPK pathway. Moreover, FFLP1s mitigated oxidative stress by activating the Nrf2/Keap1 signaling pathway and strengthened the intestinal barrier function by upregulating the expression level of tight junction proteins (occludin, claudin-1, MUC-2, and ZO-1). Furthermore, FFPL1s restored gut dysbiosis in CTX-treated immunosuppressed mice by increasing the abundance of Alloprevotella, Lachnospiraceae, and Bacteroides. They also modified the composition of fecal metabolites, leading to enhanced regulation of lipolysis in adipocytes, the cGMP-PKG pathway, the Rap1 signaling pathway, and ovarian steroidogenesis, as indicated by KEGG pathway analysis. These findings indicate that FLP1s could modulate the response of the intestinal immune system through regulation of the gut microbiota, thus promoting immune activation in CTX-treated immunosuppressed mice. FLP1s can serve as a natural protective agent against CTX-induced immune injury.

ئAntiparasitic activity of Cerastes cerastes venom on Schistosoma mansoni infected mice‏

This study investigates whether Cerastes cerastes venom (CCV) administrated at different doses (3 and 6μg/mouse) and times (a week pre-infection, the first week post-infection, and the fifth week post-infection) possesses antischistosomal activity on Schistosoma mansoni infected mice. The results showed that treatment with half lethal dose (6 μg/mouse) of CCV, at various time schedules, led to a significant decrease in the total worm burden. However, quarter lethal dose (3μg/mouse) of CCV showed a significant decrease in the total worm burden only when administered a week pre-infection. The total number of deposited eggs by females of S. mansoni was significantly decreased in the liver and the intestine of mice treated with 3μg/mouse or 6μg/mouse CCV, associated with significant alterations in the oogram pattern with significant elevation in dead eggs levels and significant decrease in the number of mature eggs. Histological examinations illustrated a significant decrease in the number and diameter of hepatic granulomas in high dose (6μg/mouse) CCV-treated groups, while it was significant only a week pre-infection in low dose (3μg/mouse) CCV-treated groups. CCV also caused several tegumental changes in treated female and male worms, including loss of the normal surface architecture, tubercular destruction, loss of tubercles' spines, oedema, erosion, membrane blebbing, and swelling. S. mansoni-infected mice groups treated with CCV (6μg/mouse) a week before infection and at fifth week post-infection had, in all individuals up to a dilution of 1:1600, higher levels of antibodies against adult worm antigen. The current investigation found that C. cerastes venom has potential antischistosomal action in a time and dose-dependent manner (more enhanced antischistosomal effects at a dose of 6 μg and in the group treated in a week before infection), in addition to its potential immunomodulatory effect against schistosomiasis infection. More studies will be required to identify the venom's active ingredients that affect the host's immunology. This information could be used in the future to develop novel antischistosomal therapies.

Intestinal IFNα4 promotes 15-HETE diet-induced pulmonary hypertension

ObjectivesPulmonary arterial hypertension (PAH) is characterized by the remodeling of the pulmonary vascular bed leading to elevation of the pulmonary arterial pressure. Oxidized fatty acids, such as hydroxyeicosatetraenoic acids (HETEs), play a critical role in PAH. We have previously established that dietary supplementation of 15-HETE is sufficient to cause PH in mice, suggesting a role for the gut-lung axis. However, the mechanisms are not known.ApproachAnalysis of RNA-seq data obtained from the lungs and intestines of mice on 15-HETE diet together with transcriptomic data from PAH patient lungs identified IFN inducible protein 44 (IFI44) as the only gene significantly upregulated in mice and humans. We demonstrate that IFI44 is also significantly increased in PBMCs from PAH patients. In mice, 15-HETE diet enhances IFI44 and its inducer IFN⍺4 expression sequentially in the intestine first and then in the lungs. IFI44 expression in PAH is highly correlated with expression of Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL), which is upregulated in CD8 cells in PH lungs of both mice and humans. We show that IFNα4 produced by intestinal epithelial cells facilitates IFI44 expression in CD8 cells. Finally, we demonstrate that IFN receptor 1-KO in mice do not develop PH on 15-HETE diet. In addition, silencing IFI44 expression in the lungs of mice on 15-HETE diet prevents the development of PH and is associated with significantly lower expression of IFI44 and TRAIL in CD8 cells in the lungs.ConclusionOur data reveal a novel gut-lung axis driven by 15-HETE in PH.

Recombinant Saccharomyces cerevisiae EBY100/pYD1-FaeG: a candidate for an oral subunit vaccine against F4+ ETEC infection.

Diarrheal diseases attributable to multidrug-resistant F4+ enterotoxigenic Escherichia coli (ETEC) are escalating in severity, posing significant risks to the health and safety of both humans and animals. This study used Saccharomyces cerevisiae EBY100 to display the FaeG subunit of F4 colonizing factor as an oral vaccine against F4+ ETEC infection. Mice were orally immunized twice with 108 CFU of EBY100/pYD1-FaeG, followed by a challenge with F4+ ETEC EC6 on day 7 post-immunization. The results showed that the recombinant strain EBY100/pYD1-FaeG orally enhanced the growth of the small intestine villi, significantly boosted the expression of tight junction proteins (ZO-1, Occludin, MUC2, and Claudin) (P < 0.05), and modulated the gut microbiota composition. Additionally, immunization with EBY100/pYD1-FaeG also upregulated the levels of IL-2, IL-4, and IFN-γ in the intestines of mice (P < 0.01), while serum IgG and fecal sIgA titer significantly increased (P < 0.05). These immune responses enhanced the capacity to fight against ETEC, leading to an increased survival rate of mice and relieved damage to tissues and organs of mice infection. In summary, the study suggested that the recombinant Saccharomyces cerevisiae EBY100/pYD1-FaeG could effectively stimulate the immune response and generate specific antibodies against F4+ ETEC, showing its potential to serve as a subunit oral vaccine candidate for preventing F4+ ETEC infection.IMPORTANCEThe multidrug-resistant F4+ enterotoxigenic Escherichia coli (ETEC) strains are the primary clinical pathogens responsible for post-weaning diarrhea in piglets, resulting in substantial economic losses in the pig farming industry. In the study, we developed an oral vaccine candidate, Saccharomyces cerevisiae EBY100/pYD1-FaeG, to prevent diarrhea caused by multidrug-resistant F4+ ETEC. Oral administration of EBY100/pYD1-FaeG significantly enhanced immune responses, improved intestinal health, and provided protection against F4+ ETEC infection in mice. This approach offers a potential application prospect for preventing F4+ ETEC infections that lead to post-weaning diarrhea in clinical settings and provides a promising solution for addressing the growing threat of antibiotic resistance in bacterial pathogens.

Dietary Bovine Lactoferrin Reduces the Deleterious Effects of Lipopolysaccharide Injection on Mice Intestine.

Injection of lipopolysaccharides (LPS) in experimental models induces a systemic inflammatory response that is associated with deleterious effects on intestinal morphology and physiology. In this study, we have studied in female mice the effects of dietary supplementation with bovine lactoferrin (bLF) given before intraperitoneal injection of LPS on jejunum and colon. The first study evaluated the efficiency of different bLF and LPS concentrations to determine the optimal experimental conditions. For the second study mice were fed with 1% bLF before the LPS challenge (3 mg/kg body weight). Plasmatic markers of inflammation, intestinal morphology, permeability, and expression of genes related to epithelial differentiation, epithelial barrier function and intestinal inflammation in both small intestine and colon were evaluated. bLF ingestion before the LPS challenge reduced the TNF-α circulating concentration, compared to control animals. This decrease in plasma TNF-α was correlated with improved intestinal permeability. The morphology of jejunal epithelium, which was affected by LPS challenge, was partly maintained by bLF. Measurement of the expression of genes encoding proteins involved in epithelial differentiation, intestinal inflammation, and epithelial barrier function suggests an overall protective effect of bLF against the adverse effects of LPS in the jejunum. In the colon, the effects of bLF ingestion on the subsequent LPS challenge, although protective, remain different when compared with those observed on jejunum. Taken together, our data indicate that bLF dietary supplementation does have a protective effect on the deleterious intestinal alterations induced by LPS systemic inflammation.

Comparison of Crohn’s disease-associated adherent-invasive Escherichia coli (AIEC) from France and Hong Kong: results from the Pacific study

ABSTRACT Association between ileal colonization by Adherent-Invasive Escherichia coli (AIEC) and Crohn’s disease (CD) has been widely described in high-incidence Western countries but remains unexplored in Asian countries with a fast increase in CD incidence. In the PACIFIC study, we compared the characteristics of AIEC pathobionts retrieved from ileal biopsies of CD patients enrolled in France (FR) and Hong Kong (HK). The prevalence of AIEC was similar in France (24.5%, 25/102) and Hong Kong (30.0%, 18/60) (p = 0.44). No difference was observed between the two populations of AIEC regarding adhesion and invasion levels. When tested for antibiotic resistance, the proportion of AIEC strains resistant to ampicillin, piperacillin, tobramycin, and gentamicin was significantly higher in HK AIEC strains compared to French strains. AIEC strains from FR or HK population were both able to persist in the mice intestine (DSS-treated CEABAC10 mice model). Moreover, genomic analysis of 25 FR and 17 hK AIEC strains using next-generation sequencing revealed the co-existence of several virulence factors associated with enteric E. coli pathotypes, although no single virulence factor was significantly associated with either country of origin or AIEC status. In vitro, all AIEC strains (FR and HK) were sensitive to the EcoActive™ phage cocktail, suggesting that it could be a promising option to target AIEC in CD across the world.