Epithelial integrity, junctional complexes, and biomarkers associated with intestinal functions

Silent information regulator 2 deficiency exacerbates chronic cold exposure-induced colonic injury and p65 activation in mice

Cold is a common stressor that threatens colonic health by affecting internal homeostasis. From the literature, Silent information regulator 2 (SIRT2) may have important roles during cold stress, but this conjecture requires investigation. To address this knowledge gap, we investigated the effects of SIRT2 on colonic injury in chronically cold-exposure mice. In a previous study, we showed that SIRT2 regulated p65 activation after cold exposure. In the current study, mice were exposed to 4 °C for 3 h/day for 3 weeks to simulate a chronic cold exposure environment. Chronic cold exposure shortened colon length, disrupted tight junctions in colonic epithelial tissue, and disordered colonic flora. Chronic cold exposure also increased p65 acetylation levels, promoted nuclear factor (NF)-κB activation, and increased the expression of its downstream pro-inflammatory factors, while SIRT2 knockdown aggravated the consequences of tissue structure disruption and increased inflammatory factors brought about by chronic cold exposure to some extent, but could alleviate the downregulation of colonic tight junction-related proteins to some extent. We also observed direct SIRT2 regulatory effects toward p65, and in Caco-2 cells treated with lipopolysaccharide (LPS), SIRT2 knockdown increased p65 acetylation levels and pro-inflammatory factor expression, while SIRT2 overexpression reversed these phenomena. Therefore, SIRT2 deletion exacerbated chronic cold exposure-induced colonic injury and p65 activation in mice. Mechanistically, p65 modification by SIRT2 via deacetylation may affect NF-κB signaling. These findings suggest that SIRT2 is a key target of colonic health maintenance under chronic cold exposure conditions.

Microbial Community and Metabolome Analysis of the Porcine Intestinal Damage Model Induced by the IPEC-J2 Cell Culture-Adapted Porcine Deltacoronavirus (PDCoV) Infection

This study was conducted to elucidate the intestinal damage induced by the IPEC-J2 cell culture-passaged PDCoV. The results showed that PDCoV disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, PDCoV induced an imbalance in the intestinal flora and disturbed its stability. Microbial community profiling revealed bacterial enrichment (e.g., Proteobacteria) and reduction (e.g., Firmicutes and Bacteroidetes) in the PDCoV-inoculated piglet model. In addition, metabolomics analysis indicated that 82 named differential metabolites were successfully quantified, including 37 up-regulated and 45 down-regulated metabolites. Chenodeoxycholic acid, sphingosine, and oleanolic aldehyde levels were reduced in PDCoV-inoculated piglets, while phenylacetylglycine and geranylgeranyl-PP levels were elevated. Correlation analysis indicated a negative correlation between Escherichia-Shigella and choline, succinic acid, creatine, phenyllactate, and hippuric acid. Meanwhile, Escherichia-Shigella was positively correlated with acetylcholine, L-Glutamicacid, and N-Acetylmuramate. Roseburia, Lachnospiraceae_UCG-010, Blautia, and Limosilactobacillus were negatively and positively correlated with sphingosine, respectively. These data suggested PDCoV-inoculated piglets exhibited significant taxonomic perturbations in the gut microbiome, which may result in a significantly altered metabolomic profile.

Cingulin family: Structure, function and clinical significance

Cingulin and its paralog paracingulin are vital components of the apical junctional complex in vertebrate epithelial and endothelial cells. They are both found in tight junctions (TJ), and paracingulin is also detectable in adherens junctions (AJ) as TJ cytoplasmic plaque proteins. Cingulin and paracingulin interact with other proteins to perform functions. They interact with cytoskeletal proteins, modulate the activity of small GTPases, such as RhoA and Rac1, and regulate gene expression. In addition, cingulin and paracingulin regulate barrier function and many pathological processes, including inflammation and tumorigenesis. In this review, we summarize the discovery and structure, expression and subcellular distribution, and molecular interactions of cingulin family proteins and discuss their role in development, physiology, and pathological processes.

Adenosine in Intestinal Epithelial Barrier Function

At the intestinal front, several lines of defense are in place to resist infection and injury, the mucus layer, gut microbiome and strong epithelial junctions, to name a few. Their collaboration creates a resilient barrier. In intestinal disorders, such as inflammatory bowel disease (IBD), barrier function is compromised, which results in rampant inflammation and tissue injury. In response to the destruction, the intestinal epithelium releases adenosine, a small but powerful nucleoside that functions as an alarm signal. Amidst the chaos of inflammation, adenosine aims to restore order. Within the scope of its effects is the ability to regulate intestinal epithelial barrier integrity. This review aims to define the contributions of adenosine to mucus production, microbiome-dependent barrier protection, tight junction dynamics, chloride secretion and acid-base balance to reinforce its importance in the intestinal epithelial barrier.

The significance of gut microbiota in the etiology of autoimmune hepatitis: a narrative review

Autoimmune hepatitis (AIH) is a chronic inflammatory disease of the liver that is mediated by autoimmunity and has complex pathogenesis. Its prevalence has increased globally. Since the liver is the first organ to be exposed to harmful substances, such as gut-derived intestinal microbiota and its metabolites, gut health is closely related to liver health, and the "liver-gut axis" allows abnormalities in the gut microbiota to influence the development of liver-related diseases such as AIH. Changes in the composition of the intestinal microbiota and its resultant disruption of the intestinal barrier and microbial transport are involved in multiple ways in the disruption of immune homeostasis and inflammation, thereby influencing the development of AIH. In terms of the mechanisms involved in immune, the gut microbiota or its metabolites, which is decreased in secondary bile acids, short-chain fatty acids (SCFAs), and polyamines, and increased in lipopolysaccharide (LPS), branched-chain amino acids (BCAA), tryptophan metabolite, amino acid, and bile acid, can disrupt immune homeostasis by activating various immune cells and immune-related signaling pathways, resulting in aberrant activation of the immune system. Clarifying this mechanism has significant clinical implications for the treatment of AIH with drugs that target intestinal microbiota and related signaling pathways. Therefore, this narrative review summarizes the progress in exploring the involvement of gut microbiota in the pathogenesis of AIH, with the aim of helping to improve the precise targeting of therapeutic treatments against AIH for the benefit of clinical AIH treatment.

Nanocarriers transport across the gastrointestinal barriers: The contribution to oral bioavailability via blood circulation and lymphatic pathway

Oral administration is the preferred route of drug delivery in clinical practice due to its noninvasiveness, safety, convenience, and high patient compliance. The gastrointestinal tract (GIT) plays a crucial role in facilitating the targeted delivery of oral drugs. However, the GIT presents multiple barriers that impede drug absorption, including the gastric barrier in the stomach and the mucus and epithelial barriers in the intestine. In recent decades, nanotechnology has emerged as a promising approach for overcoming these challenges by utilizing nanocarrier-based drug delivery systems such as liposomes, micelles, polymeric nanoparticles, solid lipid nanoparticles, and inorganic nanoparticles. Encapsulating drugs within nanocarriers not only protects them from degradation but also enhances their transport and absorption across the GIT, ultimately improving oral bioavailability. The aim of this review is to elucidate the mechanisms underlying nanocarrier-mediated transportation across the GIT into systemic circulation via both the blood circulation and lymphatic pathway.

Different levels of healing in inflammatory bowel diseases: mucosal, histological, transmural, barrier and complete healing

Mucosal healing on endoscopy has emerged as a key prognostic parameter in the management of patients with IBD (Crohn's disease, ulcerative colitis/UC) and can predict sustained clinical remission and resection-free survival. The structural basis for this type of mucosal healing is a progressive resolution of intestinal inflammation with associated healing of ulcers and improved epithelial barrier function. However, in some cases with mucosal healing on endoscopy, evidence of histological activity in mucosal biopsies has been observed. Subsequently, in UC, a second, deeper type of mucosal healing, denoted histological healing, was defined which requires the absence of active inflammation in mucosal biopsies. Both levels of mucosal healing should be considered as initial events in the resolution of gut inflammation in IBD rather than as indicators of complete transmural healing. In this review, the effects of anti-inflammatory, biological or immunosuppressive agents as well as small molecules on mucosal healing in clinical studies are highlighted. In addition, we focus on the implications of mucosal healing for clinical management of patients with IBD. Moreover, emerging techniques for the analysis of mucosal healing as well as potentially deeper levels of mucosal healing such as transmural healing and functional barrier healing of the mucosa are discussed. Although none of these new levels of healing indicate a definitive cure of the diseases, they make an important contribution to the assessment of patients' prognosis. The ultimate level of healing in IBD would be a resolution of all aspects of intestinal and extraintestinal inflammation (complete healing).

Investigating the Association Between Diet-Induced "Leaky Gut" and the Development of Prediabetes

INTRODUCTION

Chronic consumption of a high-calorie diet compromises the gut microbiota and the integrity of the intestinal wall, which causes translocation of bacterial lipopolysaccharides (LPS) into the blood. This elicits the secretion of pro-inflammatory cytokines, resulting in inflammation. However, how a high-fat high carbohydrate diet affects intestinal permeability and its possible role in the development of prediabetes have not been investigated. This study investigated the effects of HFHC diet-induced prediabetes on gut microbiota and intestinal permeability in male Sprague Dawley rats.

METHODS

The animals were randomly assigned into the non-prediabetic (NPD) and diet-induced prediabetic (PD) groups (n=6) for 20 weeks. Then, the fecal samples were analyzed to measure the gut microbiota level of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Blood glucose, plasma insulin, serum zonulin, plasma LPS, soluble CD14, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and intestinal fatty-acid binding protein (IFABP) concentrations were measured.

RESULTS

The PD group had a reduction in the Firmicutes and an increase in Bacteroidetes and Proteobacteria levels compared to those in the NPD group. Blood glucose, insulin concentration, serum zonulin, and plasma sCD14 concentrations in the PD group increased significantly, while plasma LPS concentrations were similar to the NPD group. Concentrations of plasma TNF-α, IL-6, CRP, and IFABP, an intracellular protein expressed in the intestine, increased in PD compared to the NPD group.

CONCLUSIONS

the study results cumulatively suggest that chronic consumption of the HFHC diet may be associated with the dysregulation of gut microbiota, leading to increased intestinal permeability.

A personalized management approach in disorders of the irritable bowel syndrome spectrum

Symptoms of the disorders across the irritable bowel syndrome (IBS) spectrum include several different, usually postprandial, abdominal complaints. Up to date, dietary treatments of the IBS have neither been personalized nor diagnosed with sufficient scientific evidence. They have mostly been treated using 'one-size-fits-all' approaches. Such include exclusion diets, a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet, and gluten-free diets, lactose-free diets, a diet recommended by the UK National Institute for Health and Care Excellence, and a wheat-free diet. The exact pathophysiology of IBS disorders across the spectrum is still unclear. However, the symptom profile of IBS spectrum disorders seems similar to that of food intolerance/malabsorption syndromes. Celiac disease, fructose malabsorption, histamine intolerance and lactose intolerance represent food intolerance/malabsorption disorders based on the indigestion of sugars and/or proteins. Helicobacter pylori infection may potentially promote the development of IBS and, when facing a case of IBS-like symptoms, a search for intolerance/malabsorption and H. pylori should be added to find the correct treatment for the respective patient. This review will discuss why the 'one-size-fits-all' dietary approach in the treatment of complaints across the IBS spectrum cannot be successful. Hence, it will provide an overview of the most common overall dietary approaches currently used, and why those should be discouraged. Alternatively, a noninvasive diagnostic workup of the pathophysiologic factors of food intolerance/malabsorption in each patient with symptoms of the IBS spectrum is suggested. Additionally, if H. pylori is found, eradication therapy is mandatory, and if food intolerance/malabsorption is detected, an individual and personalized dietary intervention by a registered dietician is recommended.

Functional Abdominal Pain Disorders in Children May Be Associated with Food Intolerance/Malabsorption

Functional abdominal pain disorders (FAPDs) are among the most common types of chronic pain disorders in children. FAPD symptoms are characterized by chronic abdominal pain and changed bowel movements. The pathophysiology of FAPDs in children is unknown, but these conditions may have an imprecise clinical overlap to food intolerance/malabsorption. We report on 51 consecutive children (23/28 males/females; median age 15.3 years) with investigated FAPDs from 2017 to 2022 in this retrospective pilot study. Small intestinal biopsies in children demonstrated the association of lactase and diamine oxidase (DAO), which prompted us to perform hydrogen (H2) breath tests for lactose intolerance (LIT) and determine serum DAO for the evaluation of histamine intolerance (HIT) in pediatric patients with FAPDs. To complete the food intolerance/malabsorption evaluation tests, we included a search for antibodies against tissue transglutaminase to find celiac disease (CD), performed H2 breath tests to detect fructose malabsorption (FM), and conducted a search for IgA antibodies against H. pylori infection. The results demonstrate that all 51 children evaluated were diagnosed with food intolerance/malabsorption and/or various combinations thereof. Seven children showed FM, eight of the children had HIT, and eight children had LIT. The other children had combinations: thirteen children (25.5%) had HIT and LIT, seven children (9.8%) had FM with HIT, five children (13.7%) had FM and LIT, and three children (5.9%) had a triple combination of FM, HIT, and LIT. By describing this method of personalized investigation for food intolerance/malabsorption in children with FAPDs, we demonstrate that functional abdominal pain disorders may be associated with food intolerance/malabsorption. After such diagnosis in this pediatric population, a registered dietitian helped to establish a reduction and/or exclusion diet individually tailored to their symptomatology.

Impaired intestinal permeability in patients with multiple sclerosis

BACKGROUND

A number of recent studies have shown that the intestinal microbiome, part of the brain-gut axis, is implicated in the pathophysiology of multiple sclerosis. An essential part of this axis, is the intestinal barrier and gastrointestinal disorders with intestinal barrier dysregulation appear to be linked to CNS demyelination, and hence involved in the etiopathogenesis of multiple sclerosis (MS).

OBJECTIVE

The aim of this study was to evaluate the integrity of the intestinal barrier in patients with clinically definite multiple sclerosis (CDMS) and clinically isolated syndrome (CIS) using two serum biomarkers, claudin-3 (CLDN3), a component of tight epithelial junctions, and intestinal fatty acid binding protein (I-FABP), a cytosolic protein in enterocytes.

METHODS

Serum levels of CLDN3 in 37 MS patients and 22 controls, and serum levels of I-FABP in 46 MS patients and 51 controls were measured using commercial ELISA kits. Complete laboratory tests excluded the presence of gluten-related disorders in all subjects. Thirty MS patients received either disease-modifying drugs (DMD), immunosuppression (IS) or corticosteroid treatment.

RESULTS

CLDN3 levels were only significantly higher in the MS patients treated with DMD or IS compared to the control group (P=0.006). There were no differences in I-FABP serum levels between the groups. Serum CLDN3 levels did not correlate with serum I-FABP levels in CDMS, in CIS patients or controls.

CONCLUSIONS

In multiple sclerosis patients, the intestinal epithelium may be impaired with increased permeability, but without significant enterocyte damage characterized by intracellular protein leakage. Based on our data, CLDN3 serum levels appear to assess intestinal dysfunction in MS patients but mainly in treated ones.

Positive effects of selenized-oligochitosan on zearalenone-induced intestinal dysfunction in piglets

This paper assessed the positive effects of selenized-oligochitosan (SOC) on zearalenone(ZEN)-induced intestinal dysfunction in piglets. Sixty piglets were randomly divided into 4 groups. Group C was fed the basal diet as a control and Group Z was supplemented with 2 μg/g ZEN in the basal diet; Group ZS1 and ZS2 were supplemented with 0.3 or 0.5 μg/g SOC (calculated by selenium), in addition to 2 μg/g ZEN in the basal diet. After 42 days, ileal mucosal structure, digestive enzyme activities, tight junction protein mRNA expressions, plasma D-lactate and D-xylose contents, and plasma diamine oxidase activities were determined. Compare with Group C, ileal villus height, value of villus height/crypt depth, trypsin, lipase and α-amylase activities, occluding, claudin-1 and ZO-1 mRNA expressions, and plasma D-xylose levels were significantly decreased (p < 0.01) in piglets of group Z; while compare to Group C, ileal crypt depth, plasma D-lactate contents and diamine oxidase activities were significantly increased in piglets of group Z (p < 0.01 or p < 0.05). Compare with Group Z, ileal villus height, lipase and α-amylase activities, occluding, claudin-1 and ZO-1 mRNA expressions, and plasma D-xylose levels were significantly elevated in piglets of group ZS1 and ZS2 (p < 0.01); while compare to Group Z, plasma D-lactate and diamine oxidase contents were significantly reduced in piglets of group ZS1 and ZS2 (p < 0.01 or p < 0.05). Compare with Group Z, value of villus height/crypt depth and trypsin activity were significantly promoted in piglets of group ZS2 (p < 0.01); whereas ileal crypt depth was significantly reduced in piglets of group ZS2 (p <0.01).Thus, SOC can mitigate ZEN-induced intestinal dysfunction in piglets.

The diet-microbiota axis: a key regulator of intestinal permeability in human health and disease

The intestinal barrier orchestrates selective permeability to nutrients and metabolites while excluding noxious stimuli. Recent scientific advances establishing a causal role for the gut microbiota in human health outcomes have generated a resurgent interest toward intestinal permeability. Considering the well-established role of the gut barrier in protection against foreign antigens, there is mounting evidence for a causal link between gut permeability and the microbiome in regulating human health. However, an understanding of the dynamic host-microbiota interactions that govern intestinal barrier functions remains poorly defined. Furthermore, the system-level mechanisms by which microbiome-targeted therapies, such as probiotics and prebiotics, simultaneously promote intestinal barrier function and host health remain an area of active investigation. This review summarizes the recent advances in understanding the dynamics of intestinal permeability in human health and its integration with gut microbiota. We further summarize mechanisms by which probiotics/prebiotics influence the gut microbiota and intestinal barrier functions.

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.

Quercetin Ameliorates Lipopolysaccharide-Induced Duodenal Inflammation through Modulating Autophagy, Programmed Cell Death and Intestinal Mucosal Barrier Function in Chicken Embryos

Diarrhea has been a global health problem for centuries, and the treatment has become increasingly difficult duo to the antibiotics overuse and resistance. Quercetin is a common flavonoid of extracts of vegetables, fruits, and traditional Chinese herbs, however, the mechanism of quercetin alleviating LPS-induced duodenal inflammation remains elusive. Specific pathogen-free chicken embryos (n = 120) were allocated to groups including control, PBS with or without alcohol, LPS (125 ng/egg) with or without quercetin (10, 20, or 40 nmol/egg, respectively), and quercetin groups (10, 20, or 40 nmol/egg). Fifteen day-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity. At embryonic day 19, the duodena of the embryos were collected for histopathological examination, RNA extraction and real-time polymerase chain reaction, immunohistochemical investigations, and Western blotting. The results demonstrated quercetin enhanced the inflammatory cell infiltration in the Peyer's patch of the intestinal mucosa after LPS induction. The LPS-induced expressions of these inflammation-related factors (TLR4, IL-1β, MMP3, MMP9, NFKB1, IFNγ, IL-8, IL-6) were completely blocked by quercetin. Quercetin also decreased the protein expression of TLR4, IL-1β, MMP3, and MMP9 after LPS induction. Quercetin could down-regulate autophagy gene expression (ATG5, LC3-1, LC3-2, and LKB1), and decreased the protein expression of ATG5, and LC3-1/LC3-2 after LPS induction. Quercetin treatment prevented LPS-induced increases of the gene expressions of programmed cell death factors (TNFα, Fas, CASP1, CASP3, CASP12, Drp1, and RIPK1); meanwhile, quercetin decreased the protein expression of CASP1 and CASP3 after LPS challenge. LPS reduced the gene expression of mucin 2, but upregulated the mRNA and protein expression of claudin 1, occludin, and ZO-1, and this was balanced by quercetin. This evidence suggests that quercetin can alleviate duodenal inflammation induced by LPS through modulating autophagy, programmed cell death, intestinal barrier function.

Moringa oleifera leaf polysaccharide alleviates experimental colitis by inhibiting inflammation and maintaining intestinal barrier

The characteristic of ulcerative colitis (UC) is extensive colonic mucosal inflammation. Moringa oleifera (M. oleifera) is a medicine food homology plant, and the polysaccharide from M. oleifera leaves (MOLP) exhibits antioxidant and anti-inflammatory activity. The aim of this study to investigate the potential effect of MOLP on UC in a mouse model as well as the underlying mechanism. Dextran sulfate sodium (DSS) 4% in drinking water was given for 7 days to mice with UC, at the same time, MOLP (25, 50, and 100 mg/kg/day) was intragastric administered once daily during the experiment. Structural analysis revealed that MOLP had an average molecular weight (Mw) of 182,989 kDa and consisted of fucose, arabinose, rhamnose, galactose, glucose, xylose, mannose, galactose uronic acid, glucuronic acid, glucose uronic acid and mannose uronic acid, with a percentage ratio of 1.64, 18.81, 12.04, 25.90, 17.57, 12.01, 3.51, 5.28, 0.55, 1.27, and 1.43%, respectively. In addition, the features of MOLP were identified by Fourier-transform infrared (FT-IR) and spectra, X-ray diffraction (XRD). The results showed that MOLP exhibited protective efficacy against UC by alleviating colonic pathological alterations, decreasing goblet cells, crypt destruction, and infiltration of inflammatory cells caused by DSS. Furthermore, MOLP notably repressed the loss of zonula occludens-1 (ZO-1) and occludin proteins in mucosal layer, as well as up-regulating the mRNA expression of interleukin-10 (IL-10) and peroxisome proliferator-activated receptor-γ (PPAR-γ), whereas down-regulating the activation of Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor-kappa B (NF-κB) signaling pathway and the production of pro-inflammatory cytokines. Therefore, these results will help understand the protective action procedure of MOLP against UC, thereby providing significance for the development of MOLP.

Maternal exercise improves epithelial development of fetal intestine by enhancing apelin signaling and oxidative metabolism

Obesity in pregnancy is currently the leading cause of gestational complications for the mother and fetus worldwide. Maternal obesity (MO), common in western societies, impedes development of intestinal epithelium in the fetuses, which causes disorders in the nutrient absorption and intestine-related immune responses in offspring. Here, using a mouse model of maternal exercise (ME), we found that exercise during pregnancy protects the impairment of fetal intestinal morphometrical formation and epithelial development due to MO. MO decreased villus length and epithelial proliferation markers in E18.5 fetal small intestine, which was increased due to ME. The expression of the epithelial differentiation markers, Lyz1, Muc2, and Tff3, in fetal small intestine was decreased due to MO, but protected by ME. Consistently, the biomarkers related to mitochondrial biogenesis and oxidative metabolism were downregulated in MO fetal small intestine but recovered by ME. Apelin injection to dams partially mirrored the beneficial effects of ME. ME and apelin injection activated AMPK, the downstream target of apelin receptor signaling, which might mediate the improvement of fetal epithelial development and oxidative metabolism. These findings suggest that ME, a highly accessible intervention, is effective in improving fetal intestinal epithelium of obese dams. Apelin-AMPK-mitochondrial biogenesis axis provides amenable therapeutic targets to facilitate fetal intestinal development of obese mothers.

The Desmosome-Keratin Scaffold Integrates ErbB Family and Mechanical Signaling to Polarize Epidermal Structure and Function

While classic cadherin-actin connections in adherens junctions (AJs) have ancient origins, intermediate filament (IF) linkages with desmosomal cadherins arose in vertebrate organisms. In this mini-review, we discuss how overlaying the IF-desmosome network onto the existing cadherin-actin network provided new opportunities to coordinate tissue mechanics with the positioning and function of chemical signaling mediators in the ErbB family of receptor tyrosine kinases. We focus in particular on the complex multi-layered outer covering of the skin, the epidermis, which serves essential barrier and stress sensing/responding functions in terrestrial vertebrates. We will review emerging data showing that desmosome-IF connections, AJ-actin interactions, ErbB family members, and membrane tension are all polarized across the multiple layers of the regenerating epidermis. Importantly, their integration generates differentiation-specific roles in each layer of the epidermis that dictate the form and function of the tissue. In the basal layer, the onset of the differentiation-specific desmosomal cadherin desmoglein 1 (Dsg1) dials down EGFR signaling while working with classic cadherins to remodel cortical actin cytoskeleton and decrease membrane tension to promote cell delamination. In the upper layers, Dsg1 and E-cadherin cooperate to maintain high tension and tune EGFR and ErbB2 activity to create the essential tight junction barrier. Our final outlook discusses the emerging appreciation that the desmosome-IF scaffold not only creates the architecture required for skin's physical barrier but also creates an immune barrier that keeps inflammation in check.

Protective effect of homogeneous polysaccharides of Wuguchong (HPW) on intestinal mucositis induced by 5-fluorouracil in mice

BACKGROUND

In hospitalized patients, drug side effects usually trigger intestinal mucositis (IM), which in turn damages intestinal absorption and reduces the efficacy of treatment. It has been discovered that natural polysaccharides can relieve IM. In this study, we extracted and purified homogenous polysaccharides of Wuguchong (HPW), a traditional Chinese medicine, and explored the protective effect of HPW on 5-fluorouracil (5-FU)-induced IM.

METHODS AND RESULTS

First, we identified the physical and chemical properties of the extracted homogeneous polysaccharides. The molecular weight of HPW was 616 kDa, and it was composed of 14 monosaccharides. Then, a model of small IM induced by 5-FU (50 mg/kg) was established in mice to explore the effect and mechanism of HPW. The results showed that HPW effectively increased histological indicators such as villus height, crypt depth and goblet cell count. Moreover, HPW relieved intestinal barrier indicators such as D-Lac and diamine oxidase (DAO). Subsequently, western blotting was used to measure the expression of Claudin-1, Occludin, proliferating cell nuclear antigen, and inflammatory proteins such as NF-κB (P65), tumour necrosis factor-α (TNF-α), and COX-2. The results also indicated that HPW could reduce inflammation and protect the barrier at the molecular level. Finally, we investigated the influence of HPW on the levels of short-chain fatty acids, a metabolite of intestinal flora, in the faeces of mice.

CONCLUSIONS

HPW, which is a bioactive polysaccharide derived from insects, has protective effects on the intestinal mucosa, can relieve intestinal inflammation caused by drug side effects, and deserves further development and research.

The Influence of Nutrition on Intestinal Permeability and the Microbiome in Health and Disease

The leakage of the intestinal barrier and the disruption of the gut microbiome are increasingly recognized as key factors in different pathophysiological conditions, such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), chronic liver diseases, obesity, diabetes mellitus, types of cancer, and neuropsychiatric disorders. In this study, the mechanisms leading to dysbiosis and "leaky gut" are reviewed, and a short summary of the current knowledge regarding different diseases is provided. The simplest way to restore intestinal permeability and the microbiota could be ideal nutrition. Further therapeutic options are also available, such as the administration of probiotics or postbiotics or fecal microbiota transplantation.

Pediococcus pentosaceus CECT 8330 protects DSS-induced colitis and regulates the intestinal microbiota and immune responses in mice

Background

Compelling evidences demonstrated that gut microbiota dysbiosis plays a critical role in the pathogenesis of inflammatory bowel diseases (IBD). Therapies for targeting the microbiota may provide alternative options for the treatment of IBD, such as probiotics. Here, we aimed to investigate the protective effect of a probiotic strain, Pediococcus pentosaceus (P. pentosaceus) CECT 8330, on dextran sulfate sodium (DSS)-induced colitis in mice.

Methods

C57BL/6 mice were administered phosphate-buffered saline (PBS) or P. pentosaceus CECT 8330 (5 × 10⁸ CFU/day) once daily by gavage for 5 days prior to or 2 days after colitis induction by DSS. Weight, fecal conditions, colon length and histopathological changes were examined. ELISA and flow cytometry were applied to determine the cytokines and regulatory T cells (Treg) ratio. Western blot was used to examine the tight junction proteins (TJP) in colonic tissues. Fecal short-chain fatty acids (SCFAs) levels and microbiota composition were analyzed by targeted metabolomics and 16S rRNA gene sequencing, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cluster of orthologous groups of proteins (COG) pathway analysis were used to predict the microbial functional profiles.

Results

P. pentosaceus CECT 8330 treatment protected DSS-induced colitis in mice as evidenced by reducing the weight loss, disease activity index (DAI) score, histological damage, and colon length shortening. P. pentosaceus CECT 8330 decreased the serum levels of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), and increased level of IL-10 in DSS treated mice. P. pentosaceus CECT 8330 upregulated the expression of ZO-1, Occludin and the ratio of Treg cells in colon tissue. P. pentosaceus CECT 8330 increased the fecal SCFAs level and relative abundances of several protective bacteria genera, including norank_f_Muribaculaceae, Lactobacillus, Bifidobacterium, and Dubosiella. Furthermore, the increased abundances of bacteria genera were positively correlated with IL-10 and SCFAs levels, and negatively associated with IL-6, IL-1β, and TNF-α, respectively. The KEGG and COG pathway analysis revealed that P. pentosaceus CECT 8330 could partially recover the metabolic pathways altered by DSS.

Conclusions

P. pentosaceus CECT 8330 administration protects the DSS-induced colitis and modulates the gut microbial composition and function, immunological profiles, and the gut barrier function. Therefore, P. pentosaceus CECT 8330 may serve as a promising probiotic to ameliorate intestinal inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03235-8.