Vitamin A inhibits the action of LPS on the intestinal epithelial barrier function and tight junction proteins

Indole‑3‑propionic acid alleviates intestinal epithelial cell injury via regulation of the TLR4/NF‑κB pathway to improve intestinal barrier function

Indole‑3‑propionic acid (IPA), a product of Clostridium sporogenes metabolism, has been shown to improve intestinal barrier function. In the present study, in vitro experiments using NCM460 human colonic epithelial cells were performed to investigate how IPA alleviates lipopolysaccharide (LPS)‑induced intestinal epithelial cell injury, with the aim of improving intestinal barrier function. In addition, the underlying mechanism was explored. NCM460 cell viability and apoptosis were measured using the Cell Counting Kit‑8 assay and flow cytometry, respectively. The integrity of the intestinal epithelial barrier was evaluated by measuring transepithelial electrical resistance (TEER). The underlying molecular mechanism was explored using western blotting, immunofluorescence staining, a dual luciferase reporter gene assay and quantitative PCR. The results showed that 10 µg/ml LPS induced the most prominent decrease in cell viability after 24 h of treatment. By contrast, IPA effectively inhibited LPS‑induced apoptosis in the intestinal epithelial cells. Additionally, >0.5 mM IPA improved intestinal barrier function by increasing TEER and upregulating the expression of tight junction proteins (zonula occludens‑1, claudin‑1 and occludin). Furthermore, IPA inhibited the release of pro‑inflammatory cytokines (IL‑1β, IL‑6 and TNF‑α) in a dose‑dependent manner and this was achieved via regulation of the Toll‑like receptor 4 (TLR4)/myeloid differentiation factor 88/NF‑κB and TLR4/TRIF/NF‑κB pathways. In conclusion, IPA may alleviate LPS‑induced inflammatory injury in human colonic epithelial cells. Taken together, these results suggest that IPA may be a potential therapeutic approach for the management of diseases characterized by LPS‑induced intestinal epithelial cell injury and intestinal barrier dysfunction.

Effects of gossypol acetate on growth, serum biochemical parameters, and intestinal health of goslings

Free gossypol (FG), the primary antinutritional component in cottonseed meal, can adversely affect the growth and health of poultry. Although younger geese are particularly sensitive to FG, the precise effects of FG on geese remain elusive. This study aimed to investigate the effects of gossypol acetate (GA), a form of FG, on the growth, serum biochemical parameters, and intestinal health of goslings. Seventy-two healthy male goslings, aged 7-day-old with similar body weight (BW), were randomly divided into 3 groups: a control group and 2 GA-treated groups (GA25 and GA50), which were orally administered GA (25 and 50 mg/kg BW) daily for 14 d. The results showed that oral administration of GA significantly suppressed BW, altered serum parameters, and impaired intestinal health in a dose- and time-dependent manner. Specifically, GA adversely affected intestinal morphology, induced oxidative stress, and inflammation, diminished immune function, and increased intestinal permeability and apoptosis of intestinal cells, consequently impairing nutrient absorption and utilization of goslings. Overall, these data indicate that GA adversely affects the growth, serum parameters, and intestinal health of goslings, providing valuable information further to understand the toxic effects of gossypol on goslings.

Yeast β-glucan alleviates high-fat diet-induced Alzheimer's disease-like pathologies in rats via the gut-brain axis

Targeting the gut microbiota may be an emerging strategy for the prevention and treatment of Alzheimer's disease (AD). Macro-molecular yeast β-glucan (BG), derived from the yeast of Saccharomyces cerevisiae, regulates the gut microbiota. This study aimed to investigate the effect and mechanism of long-term BG in high-fat diet (HFD)-induced AD-like pathologies from the perspective of the gut microbiota. Here, we found that 80 weeks of BG treatment ameliorated HFD-induced cognitive dysfunction in rats. In the hippocampus, BG alleviated HFD-induced the activation of astrocytes, microglia, NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome pathway, and AD-like pathologies. BG modulated gut dysbiosis through increasing the levels of beneficial bacteria and short-chain fatty acids (SCFAs). BG also attenuated HFD-induced gut barrier impairment. Correlation analysis revealed a close relationship among microbiota, SCFAs, and AD-like pathologies. Furthermore, the fecal microbiota of BG-treated rats and SCFAs treatment mitigated AD-like pathologies via the NLRP3 inflammasome pathway in HFD-fed aged rats. These results suggested that long-term BG promotes the production of SCFAs derived from gut microbiota, which further inhibits NLRP3 inflammasome-mediated neuroinflammation, thereby alleviating HFD-induced AD-like pathologies in rats. BG may become a new strategy for targeting neurodegenerative diseases.

Effects of the gut microbiota and its metabolite short-chain fatty acids on endometriosis

In recent years, a growing body of research has confirmed that the gut microbiota plays a major role in the maintenance of human health and disease. A gut microbiota imbalance can lead to the development of many diseases, such as pregnancy complications, adverse pregnancy outcomes, polycystic ovary syndrome, endometriosis, and cancer. Short-chain fatty acids are metabolites of specific intestinal bacteria and are crucial for maintaining intestinal homeostasis and regulating metabolism and immunity. Endometriosis is the result of cell proliferation, escape from immune surveillance, and invasive metastasis. There is a strong correlation between the anti-proliferative and anti-inflammatory effects of short-chain fatty acids produced by gut microbes and the development of endometriosis. Given that the mechanism of action of gut microbiota and Short-chain fatty acids in endometriosis remain unclear, this paper aims to provide a comprehensive review of the complex interactions between intestinal flora, short-chain fatty acids and endometriosis. In addition, we explored potential microbial-based treatment strategies for endometriosis, providing new insights into the future development of diagnostic tests and prevention and treatment methods for endometriosis.

Susceptibility to recombinant SARS-CoV-2 spike protein entry in the lungs of high-fat diet-induced obese mice

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Obesity is a major risk factor for the development of COVID-19. Angiotensin-converting enzyme 2 (ACE2) is an essential receptor for cell entry of SARS-CoV-2. The receptor-binding domain of the S1 subunit (S1-RBD protein) in the SARS-CoV-2 spike glycoprotein binds to ACE2 on host cells, through which the virus enters several organs, including the lungs. Considering these findings, recombinant ACE2 might be utilized as a decoy protein to attenuate SARS-CoV-2 infection. Here, we examined whether obesity increases ACE2 expression in the lungs and whether recombinant ACE2 administration diminishes the entry of S1-RBD protein into lung cells. We observed that high-fat diet-induced obesity promoted ACE2 expression in the lungs by increasing serum levels of LPS derived from the intestine. S1-RBD protein entered the lungs specifically through ACE2 expressed in host lungs and that the administration of recombinant ACE2 attenuated this entry. We conclude that obesity makes hosts susceptible to recombinant SARS-CoV-2 spike proteins due to elevated ACE2 expression in lungs, and this model of administering S1-RBD protein can be applied to new COVID-19 treatments.

Challenges and opportunities in inflammatory bowel disease: from current therapeutic strategies to organoid-based models

BACKGROUND

Inflammatory bowel disease (IBD) is an increasingly prevalent global health concern that has garnered substantial attention. However, the underlying mechanisms are still unclear and the current treatments have significant limitations. Intestinal organoids provide an in vitro model to explore the pathogenesis, test the therapeutic effects, and develop regenerative treatments as well as offer the potential to transform drug discovery of IBD.

METHODS

To advance our understanding of the whole story of IBD spanning from the pathogenesis to the current therapeutic strategies and latest advancements, a comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original articles and reviews related to IBD, organoids, pathogenesis and therapy.

RESULTS

This review deciphers the etiopathogenesis and the current therapeutic approaches in the treatment of IBD. Notably, critical aspects of intestinal organoids in IBD, such as their potential applications, viability, cell renewal ability, and barrier functionality are highlighted. We also discuss the advances, limitations, and prospects of intestinal organoids for precision medicine.

CONCLUSION

The latest strides made in research about intestinal organoids help elucidate intricate aspects of IBD pathogenesis, and pave the prospective avenues for novel therapeutic interventions.

Genistein Alleviates Intestinal Oxidative Stress by Activating the Nrf2 Signaling Pathway in IPEC-J2 Cells

In the weaning period, piglets often face oxidative stress, which will cause increased diarrhea and mortality. Genistein, a flavonoid, which is extracted from leguminous plants, possesses anti-inflammatory and antioxidative bioactivities. However, little is known about whether genistein could attenuate the oxidative stress that occurs in porcine intestinal epithelial cells (IPEC-J2). Herein, this experiment was carried out to investigate the protective effects of genistein in the IPEC-J2 cells oxidative stress model. Our results disclosed that H2O2 stimulation brought about a significant diminution in catalase (CAT) activity and cell viability, as well as an increase in the levels of reactive oxygen species (ROS) in IPEC-J2 cells (p < 0.05), whereas pretreating cells with genistein before H2O2 exposure helped to alleviate the reduction in CAT activity and cell viability (p < 0.05) and the raise in the levels of ROS (p = 0.061) caused by H2O2. Furthermore, H2O2 stimulation of IPEC-J2 cells remarkably suppressed gene level Nrf2 and CAT expression, in addition to protein level Nrf2 expression, but pretreating cells with genistein reversed this change (p < 0.05). Moreover, genistein pretreatment prevented the downregulation of occludin expression at the gene and protein level, and ZO-1 expression at gene level (p < 0.05). In summary, our findings indicate that genistein possesses an antioxidant capacity in IPEC-J2 cells which is effective against oxidative stress; the potential mechanism may involve the Nrf2 signaling pathway. Our findings could offer a novel nutritional intervention strategy to enhance the intestinal health of piglets during the weaning process.

Anti-Inflammatory Effects of a Novel Acetonitrile-Water Extract of Lens Culinaris against LPS-Induced Damage in Caco-2 Cells

Natural compounds like flavonoids preserve intestinal mucosal integrity through their antioxidant, anti-inflammatory, and antimicrobial properties. Additionally, some flavonoids show prebiotic abilities, promoting the growth and activity of beneficial gut bacteria. This study investigates the protective impact of Lens culinaris extract (LE), which is abundant in flavonoids, on intestinal mucosal integrity during LPS-induced inflammation. Using Caco-2 cells as a model for the intestinal barrier, the study found that LE did not affect cell viability but played a cytoprotective role in the presence of LPS. LE improved transepithelial electrical resistance (TEER) and tight junction (TJ) protein levels, which are crucial for barrier integrity. It also countered the upregulation of pro-inflammatory genes TRPA1 and TRPV1 induced by LPS and reduced pro-inflammatory markers like TNF-α, NF-κB, IL-1β, and IL-8. Moreover, LE reversed the LPS-induced upregulation of AQP8 and TLR-4 expression. These findings emphasize the potential of natural compounds like LE to regulate the intestinal barrier and reduce inflammation's harmful effects on intestinal cells. More research is required to understand their mechanisms and explore therapeutic applications, especially for gastrointestinal inflammatory conditions.

Application of a derivative of human defensin 5 to treat ionizing radiation-induced enterogenic infection

Enterogenic infection is a common complication for patients with radiation injury and requires efficient therapeutics in the clinic. Herein, we evaluated the promising drug candidate T7E21RHD5, which is a peptide derived from intestinal Paneth cell-secreted human defensin 5. Oral administration of this peptide alleviated the diarrhea symptoms of mice that received total abdominal irradiation (TAI, γ-ray, 12 Gy) and improved survival. Pathologic analysis revealed that T7E21RHD5 elicited an obvious mitigation of ionizing radiation (IR)-induced epithelial damage and ameliorated the reduction in the levels of claudin, zonula occluden 1 and occludin, three tight junction proteins in the ileum. Additionally, T7E21RHD5 regulated the gut microbiota in TAI mice by remodeling β diversity, manifested as a reversal of the inverted proportion of Bacteroidota to Firmicutes caused by IR. T7E21RHD5 treatment also decreased the abundance of pathogenic Escherichia-Shigella but significantly increased the levels of Alloprevotella and Prevotellaceae_NK3B31, two short-chain fatty acid-producing bacterial genera in the gut. Accordingly, the translocation of enterobacteria and lipopolysaccharide to the blood, as well as the infectious inflammatory responses in the intestine after TAI, was all suppressed by T7E21RHD5 administration. Hence, this versatile antimicrobial peptide possesses promising application prospects in the treatment of IR-induced enterogenic infection.

Fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus alleviate the intestinal barrier injury and oxidative stress damage in vitro and in vivo

This study aimed to investigate the alleviative effects of fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCSSc) on the intestinal barrier injury and oxidative stress damage in vitro and in vivo. The results showed that fCS-Sc protected the intestinal barrier and improved the antioxidant function in H2O2 damaged Caco-2 cells via up-regulating the tight junction proteins and activating Keap1-Nrf2-ARE antioxidant pathway. Furthermore, administration fCS-Sc could ameliorate the weight loss and spleen index decrease in Cyclophosphamide (Cy) treated mice, improve the expressions of ZO-1, Claudin-1, Nrf2, SOD, and NQO-1 in Cy damaged colon tissue, showing significant protective effects against intestinal barrier damage and oxidative stress in vivo. fCS-Sc intervention also alleviated the gut microbiota disorder though increasing the richness and diversity of intestinal bacteria, regulating the structural composition of gut microbiota. fCS-Sc promoted the relative abundance of beneficial microbiota and inhibited the growth of harmful bacteria. This study provided a theoretical basis for the application of fCS-Sc as a prebiotic in chemotherapy.

Role of the GLP2-Wnt1 axis in silicon-rich alkaline mineral water maintaining intestinal epithelium regeneration in piglets under early-life stress

Stress-induced intestinal epithelial injury (IEI) and a delay in repair in infancy are predisposing factors for refractory gut diseases in adulthood, such as irritable bowel syndrome (IBS). Hence, it is necessary to develop appropriate mitigation methods for mammals when experiencing early-life stress (ELS). Weaning, as we all know, is a vital procedure that all mammalian newborns, including humans, must go through. Maternal separation (MS) stress in infancy (regarded as weaning stress in animal science) is a commonly used ELS paradigm. Drinking silicon-rich alkaline mineral water (AMW) has a therapeutic effect on enteric disease, but the specific mechanisms involved have not been reported. Herein, we discover the molecular mechanism by which silicon-rich AMW repairs ELS-induced IEI by maintaining intestinal stem cell (ISC) proliferation and differentiation through the glucagon-like peptide (GLP)2-Wnt1 axis. Mechanistic study showed that silicon-rich AMW activates GLP2-dependent Wnt1/β-catenin pathway, and drives ISC proliferation and differentiation by stimulating Lgr5+ ISC cell cycle passage through the G1-S-phase checkpoint, thereby maintaining intestinal epithelial regeneration and IEI repair. Using GLP2 antagonists (GLP23-33) and small interfering RNA (SiWnt1) in vitro, we found that the GLP2-Wnt1 axis is the target of silicon-rich AMW to promote intestinal epithelium regeneration. Therefore, silicon-rich AMW maintains intestinal epithelium regeneration through the GLP2-Wnt1 axis in piglets under ELS. Our research contributes to understanding the mechanism of silicon-rich AMW promoting gut epithelial regeneration and provides a new strategy for the alleviation of ELS-induced IEI.

Ageratina adenophora causes intestinal integrity damage in goats via the activation of the MLCK/ROCK signaling pathway

As a global toxin invasive species, the whole herb of Ageratina adenophora (A. adenophora) contains various sesquiterpenes, which can cause various degrees of toxic reactions characterized by inflammatory damage when ingested by animals. Current studies on the toxicity of A. adenophora have focused on parenchymatous organs such as the liver and spleen, but few studies have been conducted on the intestine as the organ that is first exposed to A. adenophora and digests and absorbs its toxic components. In this study, after feeding goats with 40 % A. adenophora herb powder for 90 d, we found that the intestinal structure of goats showed pathological changes characterized, and the damage to the small intestinal segments was more severe than that of the large intestine. The MLCK/ROCK signaling pathway was activated, the cytoskeleton underwent centripetal contraction, the composition of tight junctions between intestinal epithelial cells was altered table, Occludin, Claudin-1 and Zonula occluden (ZO-1) amount was decreased, and the intestinal mechanical barrier was disrupted. The intestinal damage markers diamine oxidase (DAO) and D-lactate (D-LA) levels were elevated. In addition, we also found that intestinal bacteria translocate and enter the portal vein to colonize the liver and mesenteric lymph nodes. The expression of intestinal pro-inflammatory factors and anti-inflammatory factors was changed, the intestinal immune function was disrupted. The present study is the first to analyze the mechanism of poisoning of A. adenophora from the intestinal tract in compound-gastric animals.

Unraveling the microbial puzzle: exploring the intricate role of gut microbiota in endometriosis pathogenesis

Endometriosis (EMs) is a prevalent gynecological disorder characterized by the growth of uterine tissue outside the uterine cavity, causing debilitating symptoms and infertility. Despite its prevalence, the exact mechanisms behind EMs development remain incompletely understood. This article presents a comprehensive overview of the relationship between gut microbiota imbalance and EMs pathogenesis. Recent research indicates that gut microbiota plays a pivotal role in various aspects of EMs, including immune regulation, generation of inflammatory factors, angiopoietin release, hormonal regulation, and endotoxin production. Dysbiosis of gut microbiota can disrupt immune responses, leading to inflammation and impaired immune clearance of endometrial fragments, resulting in the development of endometriotic lesions. The dysregulated microbiota can contribute to the release of lipopolysaccharide (LPS), triggering chronic inflammation and promoting ectopic endometrial adhesion, invasion, and angiogenesis. Furthermore, gut microbiota involvement in estrogen metabolism affects estrogen levels, which are directly related to EMs development. The review also highlights the potential of gut microbiota as a diagnostic tool and therapeutic target for EMs. Interventions such as fecal microbiota transplantation (FMT) and the use of gut microbiota preparations have demonstrated promising effects in reducing EMs symptoms. Despite the progress made, further research is needed to unravel the intricate interactions between gut microbiota and EMs, paving the way for more effective prevention and treatment strategies for this challenging condition.

All-trans retinoic acid alleviates transmissible gastroenteritis virus-induced intestinal inflammation and barrier dysfunction in weaned piglets

BACKGROUND

Transmissible gastroenteritis virus (TGEV) is one of the main pathogens causing severe diarrhea of piglets. The pathogenesis of TGEV is closely related to intestinal inflammation. All-trans retinoic acid (ATRA) is the main active metabolite of vitamin A, which has immunomodulatory and anti-inflammatory properties. However, it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in piglets. This study aimed to investigate the effects of ATRA on growth performance, diarrhea, intestinal inflammation and intestinal barrier integrity of TGEV-challenged piglets.

METHODS

In a 19-d study, 32 weaned piglets were randomly divided into 4 treatments: Control group (basal diet), TGEV group (basal diet + TGEV challenge), TGEV + ATRA5 group (basal diet + 5 mg/d ATRA + TGEV challenge) and TGEV + ATRA15 group (basal diet + 15 mg/d ATRA + TGEV challenge). On d 14, piglets were orally administered TGEV or the sterile medium.

RESULTS

Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV (P < 0.05). Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase (DAO) activity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV, and maintained intestinal barrier integrity (P < 0.05). Meanwhile, 5 mg/d ATRA feeding increased the sucrase activity and the expressions of nutrient transporter related genes (GLUT2 and SLC7A1) in jejunal mucosa of TGEV-challenged piglets (P < 0.05). Furthermore, 5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibiting the release of interleukin (IL)-1β, IL-8 and tumor necrosis factor-α (TNF-α), and promoting the secretion of IL-10 and secretory immunoglobulin A (sIgA) (P < 0.05). Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes (TLR3, TLR4, RIG-I, MyD88, TRIF and MAVS) and the phosphorylation level of nuclear factor-κB-p65 (NF-κB p65), and up-regulated the inhibitor kappa B alpha (IκBα) protein level in jejunal mucosa of TGEV-challenged piglets (P < 0.05).

CONCLUSIONS

ATRA alleviated TGEV-induced intestinal barrier damage by inhibiting inflammatory response, thus improving the growth performance and inhibiting diarrhea of piglets. The mechanism was associated with the inhibition of NF-κB signaling pathway mediated by TLR3, TLR4 and RIG-I.

Involvement and repair of epithelial barrier dysfunction in allergic diseases

The epithelial barrier serves as a critical defense mechanism separating the human body from the external environment, fulfilling both physical and immune functions. This barrier plays a pivotal role in shielding the body from environmental risk factors such as allergens, pathogens, and pollutants. However, since the 19th century, the escalating threats posed by environmental pollution, global warming, heightened usage of industrial chemical products, and alterations in biodiversity have contributed to a noteworthy surge in allergic disease incidences. Notably, allergic diseases frequently exhibit dysfunction in the epithelial barrier. The proposed epithelial barrier hypothesis introduces a novel avenue for the prevention and treatment of allergic diseases. Despite increased attention to the role of barrier dysfunction in allergic disease development, numerous questions persist regarding the mechanisms underlying the disruption of normal barrier function. Consequently, this review aims to provide a comprehensive overview of the epithelial barrier's role in allergic diseases, encompassing influencing factors, assessment techniques, and repair methodologies. By doing so, it seeks to present innovative strategies for the prevention and treatment of allergic diseases.

Taraxacum coreanum Nakai extract attenuates lipopolysaccharide-induced inflammatory responses and intestinal barrier dysfunction in Caco-2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum coreanum Nakai (TC) is a dandelion native to Korea that has long been used as a medicinal herb with antioxidant and anti-inflammatory properties. Intestinal inflammation is closely associated with intestinal epithelial barrier disruption, which leads to the progression of various intestinal diseases.

AIM OF THE STUDY

The aim of this study was to investigate the protective effects of TC extract on inflammatory responses and intestinal barrier dysfunction in lipopolysaccharide (LPS)-stimulated Caco-2 cells.

MATERIALS AND METHODS

The inhibitory effect of TC on nitric oxide (NO) and pro-inflammatory cytokines production were determined by Griess reagent and enzyme-linked immunosorbent assay, respectively. The epithelial permeability was evaluated by transepithelial electrical resistance (TEER) assay, and inflammation- and tight junction (TJ)-related protein expression were analyzed by Western blotting. In addition, the presence of ten active compounds was identified and quantified using UHPLC-ESI-MS and HPLC-DAD analyses.

RESULTS

Treatment with TC significantly reduced NO production and pro-inflammatory cytokines production [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] compared to the group treated with LPS only, particularly at 100 μg/mL. TC significantly decreased monolayer permeability as detected by TEER. In addition, the transmission of fluorescein isothiocyanate-dextran 4 across the barrier was decreased after treatment with TC. Inflammation-related proteins (inducible NO synthase, cyclooxygenase-2, TNF-α, IL-6, and IL-1β) were down-regulated after treatment with TC. In contrast, TC significantly increased the protein levels of the TJ-related protein, claudin-5. Ten phytochemicals (protocatechuic acid, chlorogenic acid, caffeic acid, scopoletin, chicoric acid, hyperoside, nicotiflorin, luteoloside, sophoricoside, and luteolin) were identified by UHPLC-ESI-MS and HPLC-DAD analysis.

CONCLUSION

Our findings suggest that ethanolic extract of TC could attenuate the LPS-induced intestinal barrier dysfunction by increasing the TJ protein and suppressing inflammatory responses.

Tert-butylhydroquinone attenuates LPS-induced pyroptosis of IPEC-J2 cells via downregulating HMGB1/TLR4/NF-κB axis

Inflammatory response induced by biological stress usually occurs in weaning piglets, it reduces the production performance of piglets and even causes death. Tert-butylhydroquinone (TBHQ) is a food additive that has the effect of anti-inflammation and anti-oxidation. However, there are few reports related to the protective mechanisms of TBHQ on lipopolysaccharide (LPS) induced injury in intestinal porcine epithelial (IPEC-J2) cells. Quantitative real-time polymerase chain reaction and western blot analysis, respectively, detected the mRNA levels and protein expressions related to pyroptosis, tight junction (TJ) protein and high-mobility group box 1/toll-like receptor 4/nuclear factor kappa-B (HMGB1/TLR4/NF-κB) axis. Localisation and expression of NOD-like receptor pyrin domain containing 3 (NLRP3), HMGB1 and P-NF-κB proteins detected by immunofluorescence. The results showed that TBHQ (12.5 and 25 μM) can increase cell activity and reduce intracellular lactate dehydrogenase (LDH) levels in a dose-dependent manner. LPS significantly decreases cell viability and increases the LDH level. However, pretreatment with TBHQ evidently increases cell viability and decreases the LDH level of IPEC-J2 cells. In addition, treatment with LPS decreased the mRNA level and protein expression of zonula occludens-1, occludin and claudin-1, and increased the mRNA level and protein expression of pyroptosis and HMGB1/TLR4/NF-κB axis. Interestingly, pretreatment with TBHQ increased the TJ protein expressions as well as decreased the mRNA level and protein expressions of pyroptosis and HMGB1/TLR4/NF-κB axis. Moreover, the results of immunofluorescence showed that TBHQ significantly reduced the expression of NLRP3, HMGB1 and P-NF-κB in LPS-induced injury of IPEC-J2 cells. Therefore, we come to the conclusion that TBHQ attenuates LPS-induced pyroptosis in IPEC-J2 cells through downregulation of the HMGB1/TLR4/NF-κB axis, TBHQ may become a potential feed additive for preventing inflammatory diarrhoea in piglets.

Long-term administration of probiotics prevents gastrointestinal mucosal barrier dysfunction in septic mice partly by upregulating the 5-HT degradation pathway

Sepsis can impair gastrointestinal (GI) barrier integrity. Oral probiotics (PT) can maintain the balance of GI microflora and improve GI function. 5-Hydroxytryptamine (5-HT) is a key promoter of GI injury caused by sepsis. However, the mechanism by which PT attenuates sepsis by regulating 5-HT is not fully understood. In this study, C57BL6 mice were intragastric administrated with normal saline (NC) or PT once a day for 4 weeks before cecal ligation and puncture (CLP). Compared with NC-CLP mice, PT-CLP mice had lower clinical score, higher body temperature. The survival rate of PT-CLP mice was significantly improved. The levels of inflammatory cytokines and 5-HT were obviously decreased in PT-CLP mice, and GI peristalsis and barrier function were enhanced. Moreover, sepsis downregulated the expression of tight junction proteins, while PT pretreatment could maintain them at the level of sham operation group. Furthermore, PT pretreatment increased the expression of serotonin transporter and monoamine oxidase A. PT administration could inhibit NF-κB activity, and activate ERK activity. In conclusion, long-term supplementation of PT before CLP can prevent sepsis-induced GI mucosal barrier dysfunction in mice, which may be partially mediated by upregulating the 5-HT degradation pathway via activating ERK signaling.

Lactobacillus plantarum ST-III culture supernatant protects against acute alcohol-induced liver and intestinal injury

The beneficial effects of probiotics have been studied in inflammatory bowel disease, nonalcoholic steatohepatitis, and alcoholic liver disease (ALD). Probiotic supplements are safer and more effective; however, their potential mechanisms are unclear. An objective of the current study was to examine the effects of extracellular products of Lactobacillus plantarum on acute alcoholic liver injury. Mice on a standard chow diet were supplemented with Lactobacillus plantarum ST-III culture supernatant (LP-cs) for two weeks and administered alcohol at 6 g/kg body weight by gavage. Alcohol-induced liver injury was assessed by measuring plasma alanine aminotransferase activity levels and triglyceride content determined liver steatosis. Intestinal damage and tight junctions were assessed using histochemical staining. LP-cs significantly inhibited alcohol-induced fat accumulation, inflammation, and apoptosis by inhibiting oxidative stress and endoplasmic reticulum stress. LP-cs significantly inhibited alcohol-induced intestinal injury and endotoxemia. These findings suggest that LP-cs alleviates acute alcohol-induced liver damage by inhibiting oxidative stress and endoplasmic reticulum stress via one mechanism and suppressing alcohol-induced increased intestinal permeability and endotoxemia via another mechanism. LP-cs supplements are a novel strategy for ALD prevention and treatment.

Intestinal permeability in patients undergoing stem cell transplantation correlates with systemic acute phase responses and dysbiosis

Intestinal permeability may correlate with adverse outcomes during hematopoietic stem cell transplantation (HSCT), but longitudinal quantification with traditional oral mannitol and lactulose is not feasible in HSCT recipients because of mucositis and diarrhea. A modified lactulose:rhamnose (LR) assay is validated in children with environmental enteritis. Our study objective was to quantify peri-HSCT intestinal permeability changes using the modified LR assay. The LR assay was administered before transplant, at day +7 and +30 to 80 pediatric and young adult patients who received allogeneic HSCT. Lactulose and rhamnose were detected using urine mass spectrometry and expressed as an L:R ratio. Metagenomic shotgun sequencing of stool for microbiome analyses and enzyme-linked immunosorbent assay analyses of plasma lipopolysaccharide binding protein (LBP), ST2, REG3α, claudin1, occludin, and intestinal alkaline phosphatase were performed at the same timepoints. L:R ratios were increased at day +7 but returned to baseline at day +30 in most patients (P = .014). Conditioning regimen intensity did not affect the trajectory of L:R (P = .39). Baseline L:R ratios did not vary with diagnosis. L:R correlated with LBP levels (r2 = 0.208; P = .0014). High L:R ratios were associated with lower microbiome diversity (P = .035), loss of anaerobic organisms (P = .020), and higher plasma LBP (P = .0014). No adverse gastrointestinal effects occurred because of LR. Intestinal permeability as measured through L:R ratios after allogeneic HSCT correlates with intestinal dysbiosis and elevated plasma LBP. The LR assay is well-tolerated and may identify transplant recipients who are more likely to experience adverse outcomes.

Role of micronutrients in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an autoimmune intestinal disease that includes ulcerative colitis, Crohn's disease, and indeterminate colitis. Patients with IBD are often at risk for malnutrition, including micronutrient deficiencies, due to dietary restrictions and poor intestinal absorption. Micronutrients, including vitamins and minerals, play an important role in the human body's metabolism and maintenance of tissue functions. This article reviews the role of micronutrients in IBD. Micronutrients can affect the occurrence and progression of IBD by regulating immunity, intestinal flora, oxidative stress, intestinal barrier function, and other aspects. Monitoring and timely supplementation of micronutrients are important to delay progression and improve clinical symptoms in IBD patients.

YuPingFengSan ameliorates LPS-induced acute lung injury and gut barrier dysfunction in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yupingfengsan (YPFS) is a traditional Chinese medicine decoction. YPFS comprises Astragalus mongholicus Bunge (Huangqi), Atractylodes rubra Dekker (Baizhu), and Saposhnikovia divaricata (Turcz.ex Ledeb.) Schischk (Fangfeng). YPFS is commonly used to treat chronic obstructive pulmonary disease, asthma, respiratory infections, and pneumonia, but the mechanism of action remains unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its severe form of acute respiratory distress syndrome (ARDS) cause morbidity and mortality in critical patients. YPFS is a commonly used herbal soup to treat respiratory and immune system diseases. Nevertheless, the effect of YPFS on ALI remains unclear. This study aimed to investigate the effect of YPFS on lipopolysaccharide (LPS)-induced ALI in mice and elucidate its potential molecular mechanisms.

MATERIALS AND METHODS

The major components of YPFS were detected by High-performance liquid chromatography (HPLC). C57BL/6J mice were given YPFS for seven days and then treated with LPS. IL-1β, IL-6, TNF-α, IL-8, iNOS, NLRP3, PPARγ, HO-1, ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, EnaCγ mRNA in lung and ZO-1, Occludin, Claudin-1, AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ mRNA in colon tissues were measured by Real-Time Quantitative PCR (RT-qPCR). The expressions of TLR4, MyD88, NOD-like receptor thermal protein domain associated protein 3 (NLRP3), ASC, MAPK signaling pathway, Nrf2, and HO-1 in the lung were detected by Western blot. Plasma inflammatory factors Interleukin (IL)-1β, IL-6, and Tumor Necrosis Factor-α (TNF-α) were determined by Enzyme-linked Immunosorbent Assay (ELISA). Lung tissues were processed for H & E staining, and colon tissues for HE, WGA-FITC, and Alcian Blue staining.

RESULTS

The results showed that YPFS administration alleviated lung injury and suppressed the production of inflammatory factors, including IL-1β, IL-6, and TNF-α. Additionally, YPFS reduced pulmonary edema by promoting the expressions of aquaporin and sodium channel-related genes (AQP3, AQP4, AQP5, ENaCα, ENaCβ, and EnaCγ). Further, YPFS intervention exhibited a therapeutic effect on ALI by inhibiting the activation of the NLRP3 inflammasome and MAPK signaling pathways. Finally, YPFS improved gut barrier integrity and suppressed intestinal inflammation in LPS-challenged mice.

CONCLUSIONS

YPFS protected mice against LPS-induced ALI by attenuating lung and intestinal tissue damage. This study sheds light on the potential application of YPFS to treat ALI/ARDS.

Colon-Targeted Release of Turmeric Nonextractable Polyphenols and Their Anticolitis Potential via Gut Microbiota-Dependent Alleviation on Intestinal Barrier Dysfunction in Mice

Solid evidence has emerged supporting the role of nonextractable polyphenols (NEPs) and dietary fibers (DFs) as gut microbiota modulators. This study aims to elucidate gut microbiota-dependent release of turmeric NEPs and examine the possible anti-inflammatory mechanism in the dextran sulfate sodium-induced ulcerative colitis (UC) model. 1.5% DSS drinking water-induced C57BL/6J mice were fed a standard rodent chow supplemented with or without 8% extractable polyphenols (EPs), NEPs, or DFs for 37 days. The bound curcumin, demethoxycurcumin, and bisdemethoxycurcumin in NEPs were released up to 181.5 ± 10.6, 65.2 ± 6.0, and 69.5 ± 7.6 μg/mL by in vitro gut microbiota-simulated fermentation and released into the colon of NEP-supplemented mice by 5.7-, 11.0-, and 7.8-fold higher than pseudo germ-free mice, respectively (p < 0.05). NEPs also enhanced the colonic microbiota-dependent production of short-chain fatty acids in vitro and in vivo (p < 0.05). Interestingly, NEP feeding significantly improved the DSS-caused gut microbiota disorder, epithelial barrier damage, and inflammation of UC mice better than EPs or DFs (p < 0.05). Meanwhile, the pseudo germ-free mice supplemented with NEPs failed to ameliorate UC symptoms. These findings manifest that turmeric NEPs as macromolecular carriers exert the target delivery of polyphenols into the colon for regulating gut microbiota to restore the impaired gut barrier function for alleviation of inflammation.

Effect of dietary antioxidants on excretion of perfluorooctanoic acid (PFOA) via regulating uptake transporters expression and intestinal permeability in mice

Dietary antioxidants, including 2,6-di-tert-butyl-hydroxytoluene (BHT), α-tocopherol (αT) and tea polyphenol (TP), have been widely used in food. However, no data about the effect of food antioxidants on PFOA excretion were available. In this study, excretion of PFOA toward mice (four mice in each group) under the influence of co-ingested food antioxidants (i.e., BHT, αT, and TP) were investigated, and mechanism involved in excretion of PFOA, including RNA expression of uptake and efflux transporters in kidneys and liver involved in PFOA transport and intestinal permeability were also investigated. Chronic exposure to BHT (1.56 mg/kg) increased urinary PFOA excretion from 1795 ± 340 ng/mL (control) to 3340 ± 29.9 ng/mL (BHT treatment). TP treatment (12.5 mg/kg) decreased urinary excretion of PFOA, i.e., with a decrease percentage of 70% compared to the control. Organic anion transporting polypeptides (Oatps) act as uptake transporter mediate renal elimination or reabsorption of PFOA in the kidney. The decrease in urinary excretion of PFOA under TP treatment was associated with significantly (p < 0.05) enhanced expression of Oatp1a1 in the kidney (1.78 ± 0.58 vs 1.00 ± 0.18 in control), which facilitated renal reabsorption of PFOA and in turn decreased urinary excretion of PFOA. αT treatment (12.5 mg/kg) increased fecal PFOA excretion with a value of 228 ± 95.8 ng/g vs control (96.8 ± 22.7 ng/g). Mechanistic investigation revealed that αT treatment reduced intestinal permeability, resulting in increased fecal PFOA excretion.

Maternal Vitamin A deficiency during pregnancy and lactation induced damaged intestinal structure and intestinal flora homeostasis in offspring mice

The small intestine serves as the first channel of dietary Vitamin A (VA) and the unique organ of VA absorption and metabolism. However, there have not been extensive investigations on the exact mechanisms within VA-related changes in intestinal metabolic disorders. This research is designed to analyze whether and how VA affects intestinal metabolic phenotypes. Male C57BL/6 mice after weaning were randomly fed a VA control diet (VAC) or a VA-deficient diet (VAD) during the entire pregnancy and lactation process. After a total of 11 weeks, cohorts of VA deprived were next fed to a VA control diet (VAD-C) for another 8 weeks. The concentration of retinol was measured by a high-performance liquid chromatography system. The 16S gene sequencing was used to evaluate the intestinal microbiota changes. Through the use of histological staining, western blots, quantitative PCR, and enzyme-linked immunosorbent assays, the intestinal morphology, inflammatory factors, and intestinal permeability were all evaluated. Following the decrease of the tissue VA levels, VAD mice show a decrease in tissue VA levels, community differences, and the richness and diversity of intestinal microbiota. VAD diet-driven changes occur in intestinal microbiota, accompanied by a higher mRNA expression of intestinal inflammatory cytokines and an increase in intestinal permeability. As dietary VA is reintroduced into VAD diet-fed mice, the tissue VA levels, inflammatory response, and intestinal homeostasis profiles are all restored, which are similar to those found after the occurrence of VA-controlled changes within intestinal microbiota. VA deficiency caused the imbalance of intestinal metabolic phenotypes through a mechanism involving changes in intestinal microbiota. It is thought that intestinal microbiota metabolic influences represent a new salient and additional mechanism, which can be used as a new method to achieve the onset and treatment of the effect of VAD on intestinal homeostasis impairment.

TLR/MyD88-Mediated Inflammation Induced in Porcine Intestinal Epithelial Cells by Ochratoxin A Affects Intestinal Barrier Function

The intestinal epithelium performs vital functions such as nutrient absorption and acting as an intestinal barrier to maintain the host's homeostasis. Mycotoxin, which affects the processing and storage of animal feedstuff, is a problematic pollutant in farming products. Ochratoxin A generated by Aspergillus and Penicillium fungi causes inflammation, intestinal dysfunction, decline in growth, and reduced intake in porcine and other livestock. Despite these ongoing problems, OTA-related studies in intestinal epithelium are lacking. This study aimed to demonstrate that OTA regulates TLR/MyD88 signaling in IPEC-J2 cells and induces barrier function impairment through tight junction reduction. We measured expression of TLR/MyD88 signaling-related mRNAs and proteins. The indicator of intestinal barrier integrity was confirmed through immunofluorescence and transepithelial electrical resistance. Additionally, we confirmed whether inflammatory cytokines and barrier function were affected by MyD88 inhibition. MyD88 inhibition alleviated inflammatory cytokine levels, tight junction reduction, and damage to barrier function due to OTA. These results indicate that OTA induces TLR/MyD88 signaling-related genes and impairs tight junctions and intestinal barrier function in IPEC-J2 cells. MyD88 regulation in OTA-treated IPEC-J2 cells mitigates the tight junction and intestinal barrier function impairments. Our findings provide a molecular understanding of OTA toxicity in porcine intestinal epithelial cells.

Adjunctive therapeutic effects of micronutrient supplementation in inflammatory bowel disease

Growing evidence suggests that micronutrient status may have some impact on the course of inflammatory bowel disease (IBD). However, micronutrient deficiencies are easily overlooked during the treatment of IBD patients. There have been many studies on micronutrient supplementation, in which several clinical trials have been conducted targeting vitamin D and iron, but the current research is still preliminary for other vitamins and minerals. This review provides an overview of the adjunctive therapeutic effects of micronutrient supplementation in IBD, to summarize the available evidence, draw the attention of clinicians to micronutrient monitoring and supplementation in patients with IBD, and also provide some perspectives for future research directions.

LncRNA446 Regulates Tight Junctions by Inhibiting the Ubiquitinated Degradation of Alix after Porcine Epidemic Diarrhea Virus Infection

Porcine epidemic diarrhea (PED) is a highly contagious disease, caused by porcine epidemic diarrhea virus (PEDV), which causes huge economic losses. Tight junction-associated proteins play an important role during virus infection; therefore, maintaining their integrity may be a new strategy for the prevention and treatment of PEDV. Long noncoding RNAs (lncRNAs) participate in numerous cellular functional activities, yet whether and how they regulate the intestinal barrier against viral infection remains to be elucidated. Here, we established a standard system for evaluating intestinal barrier integrity and then determined the differentially expressed lncRNAs between PEDV-infected and healthy piglets by lncRNA-seq. A total of 111 differentially expressed lncRNAs were screened, and lncRNA446 was identified due to significantly higher expression after PEDV infection. Using IPEC-J2 cells and intestinal organoids as in vitro models, we demonstrated that knockdown of lncRNA446 resulted in increased replication of PEDV, with further damage to intestinal permeability and tight junctions. Mechanistically, RNA pulldown and an RNA immunoprecipitation (RIP) assay showed that lncRNA446 directly binds to ALG-2-interacting protein X (Alix), and lncRNA446 inhibits ubiquitinated degradation of Alix mediated by TRIM25. Furthermore, Alix could bind to ZO1 and occludin and restore the expression level of the PEDV M gene and TJ proteins after lncRNA446 knockdown. Additionally, Alix knockdown and overexpression affects PEDV infection in IPEC-J2 cells. Collectively, our findings indicate that lncRNA446, by inhibiting the ubiquitinated degradation of Alix after PEDV infection, is involved in tight junction regulation. This study provides new insights into the mechanisms of intestinal barrier resistance and damage repair triggered by coronavirus. IMPORTANCE Porcine epidemic diarrhea is an acute, highly contagious enteric viral disease severely affecting the pig industry, for which current vaccines are inefficient due to the high variability of PEDV. Because PEDV infection can lead to severe injury of the intestinal epithelial barrier, which is the first line of defense, a better understanding of the related mechanisms may facilitate the development of new strategies for the prevention and treatment of PED. Here, we demonstrate that the lncRNA446 directly binds one core component of the actomyosin-tight junction complex named Alix and inhibits its ubiquitinated degradation. Functionally, the lncRNA446/Alix axis can regulate the integrity of tight junctions and potentially repair intestinal barrier injury after PEDV infection.

Gut Barrier Dysfunction and Bacterial Lipopolysaccharides in Colorectal Cancer

BACKGROUND

Inflammation is known to be an essential driver of various types of cancer. An increasing number of studies have suggested that the occurrence and development of colorectal cancer (CRC) are linked to the inflammatory microenvironment of the intestine. This assumption is further supported by the fact that patients with inflammatory bowel disease (IBD) are more likely to develop CRC. Multiple studies in mice and humans have shown that preoperative systemic inflammatory response is predictive of cancer recurrence after potentially curative resection. Lipopolysaccharides (LPS) are membrane surface markers of gram-negative bacteria, which induce gut barrier dysfunction and inflammation and might be significantly involved in the occurrence and development of CRC.

METHODS

A selective literature search was conducted in Medline and PubMed, using the terms "Colorectal Cancer", "Gut Barrier", "Lipopolysaccharides", and "Inflammation".

RESULTS

Disruption of intestinal homeostasis, including gut barrier dysfunction, is linked to increased LPS levels and is a critical factor for chronic inflammation. LPS can activate the diverse nuclear factor-κB (NF-κB) pathway via Toll-like receptors 4 (TLR4) to promote the inflammatory response, which aggravates gut barrier dysfunction and encourages CRC development. An intact gut barrier prevents antigens and bacteria from crossing the intestinal endothelial layer and entering circulation. In contrast, a damaged gut barrier triggers inflammatory responses and increases susceptibility to CRC. Thus, targeting LPS and the gut barrier might be a promising novel therapeutic approach for additional treatment of CRC.

CONCLUSION

Gut barrier dysfuction and bacterial LPS seem to play an important role in the pathogenesis and disease progression of colorectal cancer and therefore require further investigation.

Ameliorating effects of Hericium erinaceus polysaccharides on intestinal barrier injury in immunocompromised mice induced by cyclophosphamide

Hericium erinaceus is a kind of large fungus with rich nutrition and its polysaccharides exhibit various biological activities. In recent years, widespread interest has been focused on maintaining or improving intestinal health through the consumption of edible fungi. Studies have shown that hypoimmunity can damage the intestinal barrier, which in turn seriously affects human health. The aim of this work was to investigate the ameliorative effects of Hericium erinaceus polysaccharides (HEPs) on intestinal barrier damage in cyclophosphamide (CTX)-induced immunocompromised mice. The results showed that the HEP effectively increased the levels of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX), and total superoxide dismutase (T-SOD), and decreased malondialdehyde (MDA) content in the liver tissues of mice. In addition, the HEP restored the immune organ index, increased the serum levels of IL-2 and IgA, augmented the mRNA expression levels of intestinal Muc2, Reg3γ, occludin and ZO-1, and reduced intestinal permeability in mice. It was further confirmed by an immunofluorescence assay that the HEP enhanced the expression level of intestinal tight junction proteins to protect the intestinal mucosal barrier. These results suggested that the HEP could reduce intestinal permeability and enhance intestinal immune functions by increasing antioxidant capacity, tight junction proteins and immune-related factors in CTX-induced mice. In conclusion, the HEP effectively ameliorated CTX-induced intestinal barrier damage in immunocompromised mice, which provides a new application direction for the HEP as a natural immunopotentiator with antioxidant function.

Network pharmacology-based analysis on geniposide, a component of gardenia jasminoides, beneficial effects to alleviate LPS-induced immune stress in piglets

Geniposide is the main medicinal component of Gardenia jasminoides, and its content is approximately 3-8% depending on its origin. Geniposide is a class of cyclic enol ether terpene glucoside compounds with strong antioxidant, free radical quenching and cancer-inhibiting activities. Many studies have reported that geniposide has hepatoprotective, cholestatic, neuroprotective, blood sugar and blood lipid regulation, soft tissue damage treatment, antithrombotic, antitumor and other effects. As a traditional Chinese medicine, gardenia, whether used as gardenia alone, as the monomer geniposide or as the effective part of cyclic either terpenoids, has been reported to have anti-inflammatory effects when used in the right amounts. Recent studies have found that geniposide has important roles in pharmacological activities such as anti-inflammation activity, inhibition of the NF-κB/IκB pathway, and cell adhesion molecule production. In this study, we predicted the anti-inflammatory and antioxidant effects of geniposide in piglets through network pharmacology based on the LPS-induced inflammatory response-regulated signaling pathway. The effects of geniposide on changes in inflammatory pathways and cytokine levels in the lymphocytes of inflammation-stressed piglets were investigated using in vivo and in vitro models of piglet lipopolysaccharide-induced oxidative stress. Network pharmacology identified 23 target genes, of which the main pathways of action were lipid and atherosclerosis, fluid shear stress and atherosclerosis, and Yersinia infection. The main relevant target genes were VEGFA, ROCK2, NOS3, and CCL2. Validation experiments showed that the interventional effects of geniposide reduced the relative expression of NF-κB pathway proteins and genes, restored the expression of COX-2 genes to normal levels, and increased the relative expression of tight junction proteins and genes in IPEC-J2 cells. This indicates that the addition of geniposide can alleviate inflammation and improve the level of cellular tight junctions.

Efficiency of Chinese medicine Bushen Huatan formula for treatment of polycystic ovary syndrome in mice via regulating gut microbiota and PPARγ pathway

OBJECTIVES

To explore the effect and mechanism of Chinese medicine Bushen Huatan formula in treatment of polycystic ovary syndrome (PCOS).

METHODS

Twenty-four SPF female C57BL/6J mice were randomly divided into 3 groups with 8 animals in each group. Control group was given drinking water ad libitum; PCOS was induced by giving letrozole gavage and high-fat diet in model group and treatment group; treatment group received Bushen Huatan formula suspension for 35 d. The sex hormone levels of mice were detected by enzyme-linked immunosorbent assay. Ovary morphology was observed under light microscope after hematoxylin and eosin staining. The feces in the colon of mice were collected, and the gut microbiota was detected by 16S rRNA sequencing. The short chain fatty acids were detected by gas chromatography-mas spectrometry. The expression of peroxisome proliferator activated receptor (PPARγ) was detected by immunohistochemistry. The mRNA expression of mucin-2, occludin-1, tight junction protein zonula occludens 1 (ZO-1) and PPARγ in intestinal epithelium were detected by realtime RT-PCR. The expression of inducible nitric oxide synthase (iNOS) and PPARγ was detected by Western blotting.

RESULTS

Compared with the control group, the body weight, serum levels of follicle stimulating hormone, luteinizing hormone and testosterone in the model group were increased, and serum levels of estradiol were decreased (all P<0.01); the ovarian structure under light microscope was consistent with the characteristics of PCOS. Compared with the model group, the serum levels of sex hormone and ovarian structure in treatment group were improved. The overall structure of gut microbiota in PCOS model mice changed. Compared with control group, there were significantly reduced abundance of Firmicutes, and increased abundance of Verrucomicrobia, Proteobacteria and Actinobacteria inthe model group at phylum level (all P<0.05); there were significantly reduced abundance of Lactobacillus, and increased abundance of Akkermansia, Lachnoclostridium, Lactococcus and Eubacterium_coprostanoligenes at genus level (all P<0.05). The disordered condition of gut microbiota was significantly improved in treatment group. Compared with control group, the contents of acetic acid, propionic acid and butyric acid in feces of model group were significantly decreased (all P<0.05); while the contents of propionic acid and butyric acid in treatment group were significantly increased compared with model control group (both P<0.05). Compared with control group, the mRNA expression of ZO-1 and protein expression of iNOS in model group were significantly increased, and the protein expression of PPARγ and the mRNA expressions of mucin-2 and occludin-1 were significantly decreased (all P<0.05). Compared with model group, the mRNA expression of ZO-1 and protein expression of iNOS in treatment group were decreased, and the protein expression of PPARγ and the mRNA expressions of mucin-2 and occludin-1 were increased.

CONCLUSIONS

PCOS induced by letrozole high-fat diet induces microflora imbalance in mice. Chinese medicine Bushen Huatan formula may increase the level of short chain fatty acid by regulating gut microbiota, thereby activating the intestinal PPARγ pathway and improving intestinal barrier function to act as a cure for PCOS.

Core-predominant gut fungus Kazachstania slooffiae promotes intestinal epithelial glycolysis via lysine desuccinylation in pigs

BACKGROUND

Gut fungi are increasingly recognized as important contributors to host physiology, although most studies have focused on gut bacteria. Post-translational modifications (PTMs) of proteins play vital roles in cell metabolism. However, the contribution of gut fungi to host protein PTMs remains unclear. Mining gut fungi that mediate host protein PTMs and dissecting their mechanism are urgently needed.

RESULTS

We studied the gut fungal communities of 56 weaned piglets and 56 finishing pigs from seven pig breeds using internal transcribed spacer (ITS) gene amplicon sequencing and metagenomics. The results showed that Kazachstania slooffiae was the most abundant gut fungal species in the seven breeds of weaned piglets. K. slooffiae decreased intestinal epithelial lysine succinylation levels, and these proteins were especially enriched in the glycolysis pathway. We demonstrated that K. slooffiae promoted intestinal epithelial glycolysis by decreasing lysine succinylation by activating sirtuin 5 (SIRT5). Furthermore, K. slooffiae-derived 5'-methylthioadenosine metabolite promoted the SIRT5 activity.

CONCLUSIONS

These findings provide a landscape of gut fungal communities of pigs and suggest that K. slooffiae plays a crucial role in intestinal glycolysis metabolism through lysine desuccinylation. Our data also suggest a potential protective strategy for pigs with an insufficient intestinal energy supply. Video Abstract.

Association of Plasma Lipopolysaccharide-Binding Protein Concentration with Dietary Factors, Gut Microbiota, and Health Status in the Japanese General Adult Population: A Cross-Sectional Study

The influx of intestinal bacteria-derived lipopolysaccharide (LPS) into the blood has attracted attention as a cause of diseases. The aim of this study is investigating the associations between the influx of LPS, dietary factors, gut microbiota, and health status in the general adult population. Food/nutrient intake, gut microbiota, health status and plasma LPS-binding protein (LBP; LPS exposure indicator) were measured in 896 residents (58.1% female, mean age 54.7 years) of the rural Iwaki district of Japan, and each correlation was analyzed. As the results, plasma LBP concentration correlated with physical (right/left arms' muscle mass [β = -0.02, -0.03]), renal (plasma renin activity [β = 0.27], urine albumin creatinine ratio [β = 0.50]), adrenal cortical (cortisol [β = 0.14]), and thyroid function (free thyroxine [β = 0.05]), iron metabolism (serum iron [β = -0.14]), and markers of lifestyle-related diseases (all Qs < 0.20). Plasma LBP concentration were mainly negatively correlated with vegetables/their nutrients intake (all βs ≤ -0.004, Qs < 0.20). Plasma LBP concentration was positively correlated with the proportion of Prevotella (β = 0.32), Megamonas (β = 0.56), and Streptococcus (β = 0.65); and negatively correlated with Roseburia (β = -0.57) (all Qs < 0.20). Dietary factors correlated with plasma LBP concentration correlated with positively (all βs ≥ 0.07) or negatively (all βs ≤ -0.07) the proportion of these bacteria (all Qs < 0.20). Our results suggested that plasma LBP concentration in the Japanese general adult population was associated with various health issues, and that dietary habit was associated with plasma LBP concentration in relation to the intestinal bacteria.

Evaluation of the potential anti-soybean allergic activity of different forms of Lactobacillus delbrueckii subsp. bulgaricus based on cell model in vitro

Live, inactivated Lactobacillus or their metabolites have various beneficial functions, which may alleviate food allergy. This study aimed to investigate the intervention effects of three forms of Lactobacillus delbrueckii subsp. bulgaricus (Ld) on cell degranulation, intestinal barrier function, and intestinal mucosal immunity against soybean allergy. First, the intervention effect of Ld on cell degranulation was investigated using the KU812 cell degranulation model. Then, the Caco-2 cell inflammation model was used to evaluate their anti-inflammatory capacity, and the cell monolayer model was constructed to test the protective effects of different forms of Ld on the intestinal barrier. Finally, mesenteric lymph node (MLN) cells from mice were used to assess the ability of different forms of Ld to regulate the balance of cytokines associated with food allergy in the immune tissue of the intestinal mucosa. Results showed that live bacteria and heat-inactivated bacteria could inhibit the degranulation of KU812 cells, mainly by significantly inhibiting the release of histamine, IL-6 and TNF-α. Both live bacteria and heat-inactivated bacteria could also suppress the increase of IL-6 and IL-8 in Caco-2 cells induced by lipopolysaccharide (LPS). The culture supernatant of bacteria and live bacteria showed better ability to maintain the integrity and permeability of the intestinal epithelial barrier. In addition, heat-inactivated bacteria could return the values of IFN-γ and IL-10 to normal levels and restore the balance of IFN-γ/IL-4, thereby reversing the immune deviation of MLN cells. Therefore, three forms of Ld have potential for the treatment of soybean allergy.

Enhancing intestinal barrier efficiency: A novel metabolic diseases therapy

Physiologically, the intestinal barrier plays a crucial role in homeostasis and nutrient absorption and prevents pathogenic entry, harmful metabolites, and endotoxin absorption. Recent advances have highlighted the association between severely damaged intestinal barriers and diabetes, obesity, fatty liver, and cardiovascular diseases. Evidence indicates that an abated intestinal barrier leads to endotoxemia associated with systemic inflammation, insulin resistance, diabetes, and lipid accumulation, accelerating obesity and fatty liver diseases. Nonetheless, the specific mechanism of intestinal barrier damage and the effective improvement of the intestinal barrier remain to be explored. Here, we discuss the crosstalk between changes in the intestinal barrier and metabolic disease. This paper also highlights how to improve the gut barrier from the perspective of natural medicine, gut microbiota remodeling, lifestyle interventions, and bariatric surgery. Finally, potential challenges and prospects for the regulation of the gut barrier-metabolic disease axis are discussed, which may provide theoretical guidance for the treatment of metabolic diseases.

Protective Mechanism of Ethyl Gallate against Intestinal Ischemia-Reperfusion Injury in Mice by in Vivo and in Vitro Studies Based on Transcriptomics

Intestinal ischemia-reperfusion injury (IIRI) is a common clinical disease that can be life-threatening in severe cases. This study aimed to investigate the effects of ethyl gallate (EG) on IIRI and its underlying mechanisms. A mouse model was established to mimic human IIRI by clamping the superior mesenteric artery. Transcriptomics techniques were used in conjunction with experiments to explore the potential mechanisms of EG action. Intestinal histomorphological damage, including intestinal villi damage and mucosal hemorrhage, was significantly reversed by EG. EG also alleviated the oxidative stress, inflammation, and intestinal epithelial apoptosis caused by IIRI. 2592 up-regulated genes and 2754 down-regulated genes were identified after EG treatment, and these differential genes were enriched in signaling pathways, including fat digestion and absorption, and extracellular matrix (ECM) receptor interactions. In IIRI mouse intestinal tissue, expression of the differential protein matrix metalloproteinase 9 (MMP9), as well as its co-protein NF-κB-p65, was significantly increased, while EG inhibited the expression of MMP9 and NF-κB-p65. In Caco-2 cells in an established oxygen-glucose deprivation/reperfusion model (OGD/R), EG significantly reversed the decrease in intestinal barrier trans-epithelial electrical resistance (TEER). However, in the presence of MMP9 inhibitors, EG did not reverse the decreasing trend in TEER. This study illustrates the protective effect and mechanism of action of EG on IIRI and, combined with in vivo and in vitro experiments, it reveals that MMP9 may be the main target of EG action. This study provides new scientific information on the therapeutic effects of EG on IIRI.

CXCR3 Inhibition Blocks the NF-κB Signaling Pathway by Elevating Autophagy to Ameliorate Lipopolysaccharide-Induced Intestinal Dysfunction in Mice

Autophagy is a cellular catabolic process in the evolutionarily conservative turnover of intracellular substances in eukaryotes, which is involved in both immune homeostasis and injury repairment. CXCR3 is an interferon-induced chemokine receptor that participates in immune regulation and inflammatory responses. However, CXCR3 regulating intestine injury via autophagy along with the precise underlying mechanism have yet to be elucidated. In the current study, we employed an LPS-induced inflammatory mouse model and confirmed that CXCR3 knockout significantly attenuates intestinal mucosal structural damage and increases tight junction protein expression. CXCR3 knockout alleviated the LPS-induced increase in the expression of inflammatory factors including TNF-α, IL-6, p-65, and JNK-1 and enhanced autophagy by elevating LC3II, ATG12, and PINK1/Parkin expression. Mechanistically, the function of CXCR3 regarding autophagy and immunity was investigated in IPEC-J2 cells. CXCR3 inhibition by AMG487 enhanced autophagy and reduced the inflammatory response, as well as blocked the NF-κB signaling pathway and elevated the expression of the tight junction protein marker Claudin-1. Correspondingly, these effects were abolished by autophagy inhibition with the selective blocker, 3-MA. Moreover, the immunofluorescence assay results further demonstrated that CXCR3 inhibition-mediated autophagy blocked p65 nuclear translocation, and the majority of Claudin-1 was located at the tight junctions. In conclusion, CXCR3 inhibition reversed LPS-induced intestinal barrier damage and alleviated the NF-κB signaling pathway via enhancing autophagy. These data provided a theoretical basis for elucidating the immunoregulatory mechanism by targeting CXCR3 to prevent intestinal dysfunction.

Daidzein Protects Caco-2 Cells against Lipopolysaccharide-Induced Intestinal Epithelial Barrier Injury by Suppressing PI3K/AKT and P38 Pathways

The intestinal epithelium provides an important barrier against bacterial endotoxin translocation, which can regulate the absorption of water and ions. The disruption of epithelial barrier function can result in water transport and tight junction damage, or further cause diarrhea. Therefore, reducing intestinal epithelial barrier injury plays an important role in diarrhea. Inflammatory response is an important cause of intestinal barrier defects. Daidzein improving the barrier integrity has been reported, but the effect on tight junction proteins and aquaporins is not well-described yet, and the underlying mechanism remains indistinct in the human intestinal epithelium. This study aimed to investigate the effects and mechanisms of daidzein on intestinal epithelial barrier injury induced by LPS, and a barrier injury model induced by LPS was established with human colorectal epithelial adenocarcinoma cell line Caco-2 cells. We found that daidzein protected the integrity of Caco-2 cell monolayers, reversed LPS-induced downregulation of ZO-1, occludin, claudin-1, and AQP3 expression, maintained intercellular junction of ZO-1, and suppressed NF-κB and the expression of inflammatory factors (TNF-α, IL-6). Furthermore, we found that daidzein suppressed the phosphorylation of the PI3K/AKT and P38 pathway-related proteins and the level of the related genes, and the PI3K/AKT and P38 pathway inhibitors increased ZO-1, occludin, claudin-1, and AQP3 expression. The study showed that daidzein could resist LPS-induced intestinal epithelial barrier injury, and the mechanism is related to suppressing the PI3K/AKT and P38 pathways. Therefore, daidzein could be a candidate as a dietary supplementation or drug to prevent or cure diarrhea.

Effects of daidzein on antioxidant capacity in weaned pigs and IPEC-J2 cells

Our previous study found that soybean isoflavones in soybean meal play an important role in improving growth performance and antioxidant capacity in pigs. However, it is still unknown whether long-term supplementation with daidzein, an active molecule deglycosylated from daidzin, in a corn–soybean meal diet can enhance growth performance in pigs. Thus, in the present study, an animal trial was carried out to investigate the effects of dietary supplementation with daidzein on the growth performance and antioxidant capacity of pigs. A total of 80 weaned piglets (40 barrows and 40 females) were assigned to 4 treatments with 5 pens per treatment and 4 piglets per pen and fed a diet supplemented with 0, 25, 50 and 100 mg/kg daidzein for a 72-day trial. In addition, porcine intestinal epithelial cells (IPEC-J2) were used as an in vitro model to explore the underlying antioxidant mechanisms of daidzein. IPEC-J2 cells were treated with 0.6 mM hydrogen peroxide (H₂O₂) in the presence or absence of 40 μM daidzein. The results showed that adding 50 mg/kg of daidzein to the diet significantly improved body weight on day 72, average daily gain (ADG) during days 0 to 72 and plasma superoxide dismutase (SOD) activity on day 42 (P < 0.05). Treatment with 0.6 mM H₂O₂ for 1 h significantly decreased cell viability and catalase (CAT) activity and increased intracellular reactive oxygen species (ROS) levels and malondialdehyde (MDA) content (P < 0.05), while pretreatment with 40 μM daidzein prevented the decrease in cell viability and CAT activity and the increase in intracellular ROS levels and MDA content caused by H₂O₂ (P < 0.05). In addition, H₂O₂ stimulation significantly suppressed the expression of nuclear factor erythroid-2-related factor 2 (Nrf2), CAT, occludin and zonula occludens-1 (ZO-1), while pretreatment with daidzein preserved the expression of Nrf2, CAT and occludin in H₂O₂-stimulated IPEC-J2 cells (P < 0.05). In conclusion, our results suggested that long-term dietary supplementation with 50 mg/kg daidzein improved growth performance in pigs and was beneficial to the antioxidant capacity of pigs. Daidzein exerted protective effects against H₂O₂-induced oxidative stress in IPEC-J2 cells and the underlying mechanism may be related to the activation of the Nrf2 signaling pathway.

Zhilong Huoxue Tongyu Capsules' Effects on ischemic stroke: An assessment using fecal 16S rRNA gene sequencing and untargeted serum metabolomics

Zhilong Huoxue Tongyu capsule (ZHTC) is an effective traditional Chinese medicine compound for the treatment of ischemic stroke, which is widely used in clinical ischemic stroke patients. However, it is uncertain whether ZHTC affects ischemic stroke through gut microbiota and serum metabolites. In this study, a rat model of middle cerebral artery occlusion (MCAO) was prepared. By evaluating motor nerve function score, cerebral infarct size, brain tissue damage and intestinal barrier damage, it was found that ZHTC improved stroke-related symptoms in MCAO rats. Using 16S rRNA gene sequencing, fecal microbial transplantation (FMT), untargeted metabolomics, and spearman correlation analysis of gut microbiota and serum metabolites, we found that ZHTC can regulate the abundance of p_Firmicutes, p_Bacteroidota,p_Proteobacteria, g_Prevotella, and g_Lactobacillus, and regulated 23 differential metabolites. Spearman correlation analysis found that Arginine was positively correlated with p_Firmicutes, o_Clostridiales, c_Clostridia, and negatively correlated with p_Bacteroidetes, c_Bacteroidia,o_Bacteroidales; L-Lysine was negatively correlated with f_Christensenellaceae; L-methionine was positively correlated with o_Lactobacillales, f_Lactobacillaceae, and g_Lactobacillus. Altogether, this study shows for the first time that ZHTC can ameliorate ischemic stroke by modulating gut microbiota and metabolic disturbances. This lays the foundation for further revealing the causal relationship between ZHTC, gut dysbiosis, plasma metabolite levels and ischemic stroke, and provides a scientific explanation for the ameliorating effect of ZHTC on ischemic stroke.

Lactoferrin Alleviates Lipopolysaccharide-Induced Infantile Intestinal Immune Barrier Damage by Regulating an ELAVL1-Related Signaling Pathway

As the most important intestinal mucosal barrier of the main body, the innate immune barrier in intestinal tract plays especially pivotal roles in the overall health conditions of infants and young children; therefore, how to strengthen the innate immune barrier is pivotal. A variety of bioactivities of lactoferrin (LF) has been widely proved, including alleviating enteritis and inhibiting colon cancer; however, the effects of LF on intestinal immune barrier in infants and young children are still unclear, and the specific mechanism on how LF inhibits infantile enteritis by regulating immune signaling pathways is unrevealed. In the present study, we firstly performed pharmacokinetic analyses of LF in mice intestinal tissues, stomach tissues and blood, through different administration methods, to confirm the metabolic method of LF in mammals. Then we constructed in Vitro and in Vivo infantile intestinal immune barrier damage models utilizing lipopolysaccharide (LPS), and evaluated the effects of LF in alleviating LPS-induced intestinal immune barrier damage. Next, the related immune molecular mechanism on how LF exerted protective effects was investigated, through RNA-seq analyses of the mouse primary intestinal epithelial cells, and the specific genes were analyzed and screened out. Finally, the genes and their related immune pathway were validated in mRNA and protein levels; the portions of special immune cells (CD4+ T cells and CD8+ T cells) were also detected to further support our experimental results. Pharmacokinetic analyses demonstrated that the integrity of LF could reach mice stomach and intestine after oral gavage within 12 h, and the proper administration of LF should be the oral route. LF was proven to down-regulate the expression levels of inflammatory cytokines in both the primary intestinal epithelial cells and mice blood, especially LF without iron (Apo-LF), indicating LF alleviated infantile intestinal immune barrier damage induced by LPS. And through RNA-seq analyses of the mouse primary intestinal epithelial cells treated with LPS and LF, embryonic lethal abnormal vision Drosophila 1 (ELAVL1) was selected as one of the key genes, then the ELAVL1/PI3K/NF-κB pathway regulated by LF was verified to participate in the protection of infantile intestinal immune barrier damage in our study. Additionally, the ratio of blood CD4+/CD8+ T cells was significantly higher in the LF-treated mice than in the control mice, indicating that LF distinctly reinforced the overall immunity of infantile mice, further validating the strengthening bioactivity of LF on infantile intestinal immune barrier. In summary, LF was proven to alleviate LPS-induced intestinal immune barrier damage in young mice through regulating ELAVL1-related immune signaling pathways, which would expand current knowledge of the functions of bioactive proteins in foods within different research layers, as well as benefit preclinical and clinical researches in a long run.

Lipopolysaccharide downregulates the expression of ZO-1 protein through the Akt pathway

Background

Neonatal bacterial meningitis is a common neonatal disease with high morbidity, and can cause serious sequelae when left untreated. Escherichia coli is the common pathogen, and its endotoxin, lipopolysaccharide (LPS) can damage the endothelial cells, increasing the permeability of the blood-brain barrier (BBB), leading to intracranial inflammation. However, the specific mechanism of bacterial meningitis induced by LPS damaging BBB remains unclear. In this study, the mouse brain microvascular endothelial (bEND.3) cells were used as a research object to investigate whether LPS damage BBB through the PI3K/Akt pathway.

Methods

The bEND.3 cells were stimulated with different concentrations of LPS for 12 h, and the expression of tight junction proteins (ZO-1, claudin-5, occludin) was detected using western blotting. The cells were challenged with the same concentration of LPS (1ug/ml) across different timepoints (0, 2 h, 4 h, 6 h, 12 h, 24 h). Expression of TJ proteins and signal pathway molecules (PI3K, p-PI3K, Akt, p-Akt) were detected. The distribution of ZO-1 in bEND.3 cells were detected by immunofluorescence staining.

Results

A negative correlation is observed between ZO-1 and LPS concentration. Moreover, a reduced expression of ZO-1 was most significant under 1 ug/ml of LPS, and the difference was statistically significant (P < 0.05). Additionally, there is a negative correlation between ZO-1 and LPS stimulation time. Meanwhile, the expression of claudin-5 and occludin did not change significantly with the stimulation of LPS concentration and time. The immunofluorescence assay showed that the amount of ZO-1 on the surface of bEND.3 cells stimulated with LPS was significantly lower than that of the control group. After LPS stimulation, p-Akt protein increased at 2 h and peaked at 4 h. The titer of p-PI3K did not change significantly with time.

Conclusion

LPS can downregulate the expression of ZO-1; however, its effect on claudin-5 and occludin is minimal. Akt signal pathway may be involved in the regulation of ZO-1 expression induced by LPS in bEND.3 cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07752-1.

Lactobacillus rhamnosus GR-1 attenuates foodborne Bacillus cereus-induced NLRP3 inflammasome activity in bovine mammary epithelial cells by protecting intercellular tight junctions

Background

Bacillus cereus is an important pathogen that causes human food poisoning, specifically diarrhea and vomiting. B. cereus can also induce mastitis in dairy cows and has a strong survival ability in milk, as it cannot be inactivated by high-temperature short-time pasteurization. Therefore, B. cereus can enter the market through pasteurized milk and other dairy products, imposing enormous hidden dangers on food safety and human health.

Results

In this study, B. cereus 2101 (BC) was isolated from milk samples of cows with mastitis. BC grew rapidly with strong hemolysis, making it difficult to prevent mastitis and ensure food security. MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1 (LGR-1). Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1 (ZO-1) and occludin destroyed by BC. Furthermore, LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3), caspase recruitment and activation domain (ASC), Caspase-1 p20, gasdermin D (GSDMD) p30, inflammatory factors (interleukin (IL)-1β and IL-18), and cell death induced by BC. Moreover, LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides (LPS) + ATP stimulation. MAC-T cells were transfected with NLRP3 siRNA or MCC950 and/or treated with BC and/or LGR-1. NLRP3-siRNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity. Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.

Conclusions

These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows, thus ensuring food security.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00752-w.

Vitamin–Microbiota Crosstalk in Intestinal Inflammation and Carcinogenesis

Inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC) are common diseases of the digestive system. Vitamin deficiencies and gut microbiota dysbiosis have a close relationship with the risk, development, and progression of IBD and CAC. There is a strong link between vitamins and the gut microbiome. Vitamins are extremely crucial for maintaining a healthy gut microbiota, promoting growth and development, metabolism, and innate immunity. Gut microbiota can not only influence the transport process of vitamins, but also produce vitamins to compensate for insufficient food intake. Emerging evidence suggests that oral vitamin supplementation can reduce inflammation levels and improve disease prognosis. In addition, improving the diet structure and consuming foods rich in vitamins not only help to improve the vitamin deficiency, but also help to reduce the risk of IBD. Fecal microbiota transplantation (FMT) and the application of vitamin-producing probiotics can better assist in the treatment of intestinal diseases. In this review, we discuss the interaction and therapeutic roles of vitamins and gut microbiota in IBD and CAC. We also summarize the methods of treating IBD and CAC by modulating vitamins. This may highlight strategies to target gut-microbiota-dependent alterations in vitamin metabolism in the context of IBD and CAC therapy.

Benign regulation of the gut microbiota: The possible mechanism through which the beneficial effects of manual acupuncture on cognitive ability and intestinal mucosal barrier function occur in APP/PS1 mice

Background

Gut microbiota dysbiosis and intestinal barrier injury play vital roles in Alzheimer's disease (AD) onset and development. Our previous studies have demonstrated that manual acupuncture (MA) could improve the cognitive abilities of APP/PS1 mice. However, the effect of MA on the intestinal mucosal barrier and the gut microbiota mechanism through which this effect occurs remain to be clarified.

Methods

In the APP/PS1 manual acupuncture (Am) group, MA was applied in Baihui (GV20), Yintang (GV29), and Zusanli (ST36). Mice in the APP/PS1 antibiotic + manual acupuncture (Aa) group were treated with an antibiotic mixture and MA at the same time. Probiotics were delivered to the APP/PS1 probiotics (Ap) group. Alterations in spatial learning and memory, the gut microbiota, the intestinal barrier function, and the expression of glial fibrillary acidic protein (GFAP), lipopolysaccharide (LPS), and TNF-α were evaluated in each group.

Results

Compared with the C57BL/6 control (Cc) group, cognitive ability was significantly decreased, the gut microbiota structure was obviously disrupted, intestinal barrier integrity was drastically impaired, and the intestinal inflammatory response was enhanced in the APP/PS1 control (Ac) group (P < 0.01). These changes were reversed by MA and probiotics (P < 0.01 or P < 0.05), whereas antibiotics inhibited the benign regulation by MA (P < 0.01 or P < 0.05).

Conclusion

Manual acupuncture can benignly modulate gut microbiota dysbiosis, significantly reduce intestinal inflammation, and effectively alleviate the destruction of the intestinal mucosal barrier in APP/PS1 mice, and the effects are comparable to those of probiotics. The gut microbiota may play an important role in the improvement of the cognitive function and intestinal barrier function by MA.

Gut microbiota dysbiosis: The potential mechanisms by which alcohol disrupts gut and brain functions

Alcohol use disorder (AUD) is a high-risk psychiatric disorder and a key cause of death and disability in individuals. In the development of AUD, there is a connection known as the microbiota-gut-brain axis, where alcohol use disrupts the gut barrier, resulting in changes in intestinal permeability as well as the gut microbiota composition, which in turn impairs brain function and worsens the patient’s mental status and gut activity. Potential mechanisms are explored by which alcohol alters gut and brain function through the effects of the gut microbiota and their metabolites on immune and inflammatory pathways. Alcohol and microbiota dysregulation regulating neurotransmitter release, including DA, 5-HT, and GABA, are also discussed. Thus, based on the above discussion, it is possible to speculate on the gut microbiota as an underlying target for the treatment of diseases associated with alcohol addiction. This review will focus more on how alcohol and gut microbiota affect the structure and function of the gut and brain, specific changes in the composition of the gut microbiota, and some measures to mitigate the changes caused by alcohol exposure. This leads to a potential intervention for alcohol addiction through fecal microbiota transplantation, which could normalize the disruption of gut microbiota after AUD.

Role of Short Chain Fatty Acids to Counteract Inflammatory Stress and Mucus Production in Human Intestinal HT29-MTX-E12 Cells

Short chain fatty acids (SCFAs), especially butyrate (BUT), are known to promote intestinal health, but their role in the protection of intestinal barrier integrity is poorly characterized. The aim of the study was to set up an in vitro model of human colon epithelium using HT29-MTX-E12 cells to delineate the potential role of SCFAs under stress conditions. Accordingly, the HT29-MTX-E12 cells were differentiated for 42 days and subsequently exposed to dextran sulphate sodium (DSS). Further, the effects of BUT or its mixture with acetate and propionate (SCFAs-MIX) were tested to study proliferation, epithelial integrity and mucus production. The results showed that the concentration of 10% DSS for 24 h decreased the TEER about 50% compared to the control in HT29-MTX-E12 cells. The pre-treatment on HT29-MTX-E12 cells with BUT or SCFAs-MIX at specific concentrations significantly (p < 0.05) reduced the DSS-induced damage on epithelial cell integrity and permeability. Further, the treatment with specific concentrations of BUT and SCFAs-MIX for 24 h significantly promoted ZO-1, MUC2 and MUC5AC mRNA expression (p < 0.005). The present study demonstrated the suitability of HT29-MTX-E12 cells treated with DSS as an in vitro stress model of inflammatory bowel disease, which enabled us to understand the effect of bioactive SCFAs on the intestinal barrier.

Babies, Bugs, and Barriers: Dietary Modulation of Intestinal Barrier Function in Early Life

The intestinal barrier is essential in early life to prevent infection, inflammation, and food allergies. It consists of microbiota, a mucus layer, an epithelial layer, and the immune system. Microbial metabolites, the mucus, antimicrobial peptides, and secretory immunoglobulin A (sIgA) protect the intestinal mucosa against infection. The complex interplay between these functionalities of the intestinal barrier is crucial in early life by supporting homeostasis, development of the intestinal immune system, and long-term gut health. Exclusive breastfeeding is highly recommended during the first 6 months. When breastfeeding is not possible, milk-based infant formulas are the only safe alternative. Breast milk contains many bioactive components that help to establish the intestinal microbiota and influence the development of the intestinal epithelium and the immune system. Importantly, breastfeeding lowers the risk for intestinal and respiratory tract infections. Here we review all aspects of intestinal barrier function and the nutritional components that impact its functionality in early life, such as micronutrients, bioactive milk proteins, milk lipids, and human milk oligosaccharides. These components are present in breast milk and can be added to milk-based infant formulas to support gut health and immunity. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Ginsenoside Rg1 Mitigates Porcine Intestinal Tight Junction Disruptions Induced by LPS through the p38 MAPK/NLRP3 Inflammasome Pathway

Inflammation leads to porcine tight junction disruption of small intestinal epithelial cells, resulting in intestinal dysfunction. Herein, we established lipopolysaccharide (LPS)-induced in-vivo and in-vitro inflammatory models. The results revealed that LPS induced tight junction disruption in IPEC-J2 cells by downregulating tight-junction-related protein zonula occludens-1 (ZO-1), occludin and claudin-1 expression, while ginsenoside Rg1 rescued such inhibition and abrogated the upregulated expression of phosphorylation p38 MAPK. The p38 MAPK inhibitor (SB203580) showed a similar effect with Rg1 and attenuated the LPS-induced inhibition of ZO-1, occludin and claudin-1 expression, which is consistent with the reduced expression of NLRP3 inflammasome and IL-1β. Furthermore, the specific inhibitors of NLRP3 and IL-1β result in increased expression of tight-junction-related protein, demonstrating that p38 MAPK signaling was associated with Rg1 suppression of tight junction disruption. Besides, LPS treatment decreased the expression of ZO-1, occludin and claudin-1 through p38 MAPK signaling, and caused abnormal morphological changes in murine ileum. Meanwhile, Rg1 attenuated the decreased expression of ZO-1, occludin and claudin-1 and partially alleviated LPS-induced morphological changes in murine ileum. In summary, these findings characterized a novel mechanism by which Rg1 alleviates LPS-induced intestinal tight junction disruption by inhibiting the p38 MAPK-mediated NLRP3 inflammasome pathway.