Intestinal delivery of encapsulated bacteriocin peptides in cross-linked alginate microcapsules.

Oral delivery of larger bioactive peptides (>20 amino acids) to the small intestine remains a challenge due to their sensitivity to proteolytic degradation and chemical denaturation during gastrointestinal transit. In this study, we investigated the capacity of crosslinked alginate microcapsules (CLAMs) formed by spray drying to protect Plantaricin EF (PlnEF) (C-EF) in gastric conditions and to dissolve and release PlnEF in the small intestine. PlnEF is an unmodified, two-peptide (PlnE: 33 amino acids; PlnF: 34 amino acids) bacteriocin produced by Lactiplantibacillus plantarum with antimicrobial and gut barrier protective properties. After 2 h incubation in simulated gastric fluid (SGF) (pH 1.5), 43.39 % ± 8.27 % intact PlnEF was liberated from the CLAMs encapsulates, as determined by an antimicrobial activity assay. Transfer of the undissolved fraction to simulated intestinal fluid (SIF) (pH 7) for another 2 h incubation resulted in an additional release of 16.13 % ± 4.33 %. No active PlnEF was found during SGF or sequential SIF incubations when pepsin (2,000 U/ml) was added to the SGF. To test PlnEF release in C-EF contained in a food matrix, C-EF was mixed in peanut butter (PB) (0.15 g C-EF in 1.5 g PB). A total of 12.52 % ± 9.09 % active PlnEF was detected after incubation of PB + C-EF in SGF without pepsin, whereas no activity was found when pepsin was included. Transfer of the remaining PB + C-EF fractions to SIF yielded the recovery of 46.67 % ± 13.09 % and 39.42 % ± 11.53 % active PlnEF in the SIF following exposure to SGF and to SGF with pepsin, respectively. Upon accounting for the undissolved fraction after SIF incubation, PlnEF was fully protected in the CLAMs-PB mixture and there was not a significant reduction in active PlnEF when pepsin was present. These results show that CLAMs alone do not guard PlnEF bacteriocin peptides from gastric conditions, however, mixing them in PB protected against proteolysis and improved intestinal release.

Toll-like receptors 1-9 in small bowel neuroendocrine tumors-Clinical significance and prognosis.

Toll-like receptors (TLRs) are pattern recognition receptors of the innate immunity. TLRs are known to mediate both antitumor effects and tumorigenesis. TLRs are abundant in many cancers, but their expression in small bowel neuroendocrine tumors (SB-NETs) is unknown. We aimed to characterize the expression of TLRs 1-9 in SB-NETs and lymph node metastases and evaluate their prognostic relevance. The present study included 125 patients with SB-NETs, of whom 95 had lymph node metastases, from two Finnish hospitals. Tissue samples were stained immunohistochemically for TLR expression, assessed based on cytoplasmic and nucleic staining intensity and percentage of positively stained cells. Statistical methods for survival analysis included Kaplan-Meier method and Cox regression adjusted for confounding factors. Disease-specific survival (DSS) was the primary outcome. TLRs 1-2 and 4-9 were expressed in SB-NETs and lymph node metastases. TLR3 showed no positive staining. In primary SB-NETs, TLRs 1-9 were not associated with survival. For lymph node metastases, high cytoplasmic TLR7 intensity associated with worse DSS compared to low cytoplasmic intensity (26.4% vs. 84.9%, p = 0.028). Adjusted mortality hazard (HR) was 3.90 (95% CI 1.07-14.3). The expression of TLRs 1-6 and 8-9 in lymph node metastases were not associated with survival. SB-NETs and their lymph node metastases express cytoplasmic TLR 1-2 and 4-9 and nucleic TLR5. High TLR7 expression in SB-NET lymph node metastases was associated with worse prognosis. The current research has future perspective, as it can help create base for clinical drug trials to target specific TLRs with agonists or antagonists to treat neuroendocrine tumors.

Reinforcing decellularized small intestine submucosa with cellulose acetate nanofibrous and silver nanoparticles as a scaffold for wound healing applications.

BACKGROUND: The formation of chronic wounds accounts for considerable costs in health care systems. Despite the several benefits of decellularized small intestinal submucosa (SIS) as an appropriate scaffold for different tissue regeneration, it has shortcomings such as lack of antibacterial features and inappropriate mechanical properties for skin tissue regeneration. We aimed to examine the efficacy and safety of decellularized SIS scaffold enhanced with cellulose acetate (CA) and silver (Ag) nanoparticles (NPs) for healing full-thickness wounds. METHODS AND RESULTS: The scaffolds were prepared by decellularizing bovine SIS and electrospinning CA/Ag nanoparticles and characterized using a transmission electron microscope (TEM), scanning electron microscope (SEM), tensile testing, and X-ray diffraction. In vivo evaluations were performed using full-thickness excisions covered with sterile gauze as the control group, SIS, SIS/CA, and SIS/CA/Ag scaffolds on the dorsum of twenty male Wistar rats divided into four groups randomly with 21-days follow-up. All in vivo specimens underwent Masson's trichrome (MT) staining for evaluation of collagen deposition, transforming growth factor-ß (TGF-ß) immunohistochemistry (IHC), and Haematoxylin Eosin (H&E) staining. The IHC and MT data were analyzed with the ImageJ tool by measuring the stained area. The TEM results revealed that Ag nanoparticles are successfully incorporated into CA nanofibers. Assessment of scaffolds hydrophilicity demonstrated that the contact angle of SIS/CA/Ag scaffold was the lowest. The in vivo results indicated that the SIS/CA/Ag scaffold had the most significant wound closure. H&E staining of the in vivo specimens showed the formation of epidermal layers in the SIS/CA/Ag group on day 21. The percentage of the stained area of MT and TGF-ß IHC staining's was highest in the SIS/CA/Ag group. CONCLUSION: The decellularized SIS/CA/Ag scaffolds provided the most significant wound closure compared to other groups and caused the formation of epidermal layers and skin appendages. Additionally, the collagen deposition and expression of TGF-ß increased significantly in SIS/CA/Ag group.

Infant milk formula, produced by membrane filtration, promotes mucus production in the upper small intestine of young pigs.

Human breast milk promotes maturation of the infant gastrointestinal barrier, including the promotion of mucus production. In the quest to produce next generation infant milk formula (IMF), we have produced IMF by membrane filtration (MEM-IMF). With a higher quantity of native whey protein, MEM-IMF more closely mimics human breast milk than IMF produced using conventional heat treatment (HT-IMF). After a 4-week dietary intervention in young pigs, animals fed a MEM-IMF diet had a higher number of goblet cells, acidic mucus and mucin-2 in the jejunum compared to pigs fed HT-IMF (P < 0.05). In the duodenum, MEM-IMF fed pigs had increased trypsin activity in the gut lumen, increased mRNA transcript levels of claudin 1 in the mucosal scrapings and increased lactase activity in brush border membrane vesicles than those pigs fed HT-IMF (P < 0.05). In conclusion, MEM-IMF is superior to HT-IMF in the promotion of mucus production in the young gut.

The bile salt/phospholipid ratio determines the extent of in vitro intestinal lipolysis of triglycerides: Interfacial and emulsion studies.

This study focused on the protein-stabilised triglyceride (TG)/water interfaces and oil-in-water emulsions, and explored the influence of varying molar ratios of bile salts (BSs) and phospholipids (PLs) on the intestinal lipolysis of TGs. The presence of these two major groups of biosurfactants delivered with human bile to the physiological environment of intestinal digestion was replicated in our experiments by using mixtures of individual BSs and PLs under in vitro small intestinal lipolysis conditions. Conducted initially, retrospective analysis of available scientific literature revealed that an average molar ratio of 9:4 for BSs to PLs (BS/PL) can be considered physiological in the postprandial adult human small intestine. Our experimental data showed that combining BSs and PLs synergistically enhanced interfacial activity, substantially reducing oil-water interfacial tension (IFT) during interfacial lipolysis experiments with pancreatic lipase, especially at the BS/PL-9:4 ratio. Other BS/PL molar proportions (BS/PL-6.5:6.5 and BS/PL-4:9) and an equimolar amount of BSs (BS-13) followed in IFT reduction efficiency, while using PLs alone as biosurfactants was the least efficient. In the following emulsion lipolysis experiments, BS/PL-9:4 outperformed other BS/PL mixtures in terms of enhancing the TG digestion extent. The degree of TG conversion and the desorption efficiency of interfacial material post-lipolysis correlated directly with the BS/PL ratio, decreasing as the PL proportion increased. In conclusion, this study highlights the crucial role of biliary PLs, alongside BSs, in replicating the physiological function of bile in intestinal lipolysis of emulsified TGs. Our results showed different contributions of PLs and BSs to lipolysis, strongly suggesting that any future in vitro studies aiming to simulate the human digestion conditions should take into account the impact of biliary PLs - not just BSs - to accurately mimic the physiological role of bile in intestinal lipolysis. This is particularly crucial given the fact that existing in vitro digestion protocols typically focus solely on applying specific concentrations and/or compositions of BSs to simulate the action of human bile during intestinal digestion, while overlooking the presence and concentration of biliary PLs under physiological gut conditions.

Obeticholic acid attenuates the intestinal barrier disruption in a rat model of short bowel syndrome.

BACKGROUND: Short bowel syndrome (SBS) features nutrients malabsorption and impaired intestinal barrier. Patients with SBS are prone to sepsis, intestinal flora dysbiosis and intestinal failure associated liver disease. Protecting intestinal barrier and preventing complications are potential strategies for SBS treatment. This study aims to investigate the effects of farnesoid X receptor (FXR) agonist, obeticholic acid (OCA), have on intestinal barrier and ecological environment in SBS. METHODS AND RESULTS: Through testing the small intestine and serum samples of patients with SBS, impaired intestinal barrier was verified, as evidenced by reduced expressions of intestinal tight junction proteins (TJPs), increased levels of apoptosis and epithelial cell damage. The intestinal expressions of FXR and related downstream molecules were decreased in SBS patients. Then, global FXR activator OCA was used to further dissect the potential role of the FXR in a rat model of SBS. Low expressions of FXR-related molecules were observed on the small intestine of SBS rats, along with increased proinflammatory factors and damaged barrier function. Furthermore, SBS rats possessed significantly decreased body weight and elevated death rate. Supplementation with OCA mitigated the damaged intestinal barrier and increased proinflammatory factors in SBS rats, accompanied by activated FXR-related molecules. Using 16S rDNA sequencing, the regulatory role of OCA on gut microbiota in SBS rats was witnessed. LPS stimulation to Caco-2 cells induced apoptosis and overexpression of proinflammatory factors in vitro. OCA incubation of LPS-pretreated Caco-2 cells activated FXR-related molecules, increased the expressions of TJPs, ameliorated apoptosis and inhibited overexpression of proinflammatory factors. CONCLUSIONS: OCA supplementation could effectively ameliorate the intestinal barrier disruption and inhibit overexpression of proinflammatory factors in a rat model of SBS and LPS-pretreated Caco-2 cells. As a selective activator of FXR, OCA might realize its protective function through FXR activation.

Spatio-temporal dynamics of the human small intestinal microbiome and its response to a synbiotic.

Although fecal microbiota composition is considered to preserve relevant and representative information for distal colonic content, it is evident that it does not represent microbial communities inhabiting the small intestine. Nevertheless, studies investigating the human small intestinal microbiome and its response to dietary intervention are still scarce. The current study investigated the spatio-temporal dynamics of the small intestinal microbiome within a day and over 20 days, as well as its responses to a 14-day synbiotic or placebo control supplementation in 20 healthy subjects. Microbial composition and metabolome of luminal content of duodenum, jejunum, proximal ileum and feces differed significantly from each other. Additionally, differences in microbiota composition along the small intestine were most pronounced in the morning after overnight fasting, whereas differences in composition were not always measurable around noon or in the afternoon. Although overall small intestinal microbiota composition did not change significantly within 1 day and during 20 days, remarkable, individual-specific temporal dynamics were observed in individual subjects. In response to the synbiotic supplementation, only the microbial diversity in jejunum changed significantly. Increased metabolic activity of probiotic strains during intestinal passage, as assessed by metatranscriptome analysis, was not observed. Nevertheless, synbiotic supplementation led to a short-term spike in the relative abundance of genera included in the product in the small intestine approximately 2 hours post-ingestion. Collectively, small intestinal microbiota are highly dynamic. Ingested probiotic bacteria could lead to a transient spike in the relative abundance of corresponding genera and ASVs, suggesting their passage through the entire gastrointestinal tract. This study was registered to http://www.clinicaltrials.gov, NCT02018900.

Pathogenesis of chronic enteropathy associated with the SLCO2A1 gene: Hypotheses and conundrums.

Chronic enteropathy associated with the SLCO2A1 gene (CEAS) is a complex gastroenterological condition characterized by multiple ulcers in the small intestine with chronic bleeding and protein loss. This review explores the potential mechanisms underlying the pathogenesis of CEAS, focusing on the role of SLCO2A1-encoded prostaglandin transporter OATP2A1 and its impact on prostaglandin E2 (PGE2) levels. Studies have suggested that elevated PGE2 levels contribute to mucosal damage, inflammation, and disruption of the intestinal barrier. The effects of PGE2 on macrophage activation and Maxi-Cl channel functionality, as well as its interaction with nonsteroidal anti-inflammatory drugs play crucial roles in the progression of CEAS. Understanding the balance between its protective and pro-inflammatory effects and the complex interactions within the gastrointestinal tract can shed light on potential therapeutic targets for CEAS and guide the development of novel, targeted therapies.

Beneficial effect of heat-killed Lactiplantibacillus plantarum L-137 on intestinal barrier function of rat small intestinal epithelial cells.

Heat-killed Lactiplantibacillus plantarum L-137 (HK L-137) has been suggested to enhance the intestinal barrier in obese mice, leading to improvement of metabolic abnormalities and adipose tissue inflammation, and in healthy humans with overweight, leading to improvement of systemic inflammation. However, its detailed mechanism of action has not been clarified. Therefore, this study investigated the effects of HK L-137 on the permeability of rat small intestinal epithelial IEC-6 cells, tight junction-related gene and protein expression and localization, and intracellular signaling pathways involved in barrier function. Treatment of IEC-6 cells with HK L-137 for 26 h significantly reduced the permeability to fluorescein isothiocyanate-dextran (FD-4). HK L-137 also increased gene and protein expression of zonula occludens-1 (ZO-1), an important tight junction protein, without affecting the localization. Furthermore, inhibition of the extracellular signal-regulated kinase (ERK)1/2 pathway in IEC-6 cells canceled the HK L-137-related reduction in permeability to FD-4. Phosphorylation of ERK in IEC-6 cells was induced 15 min after the addition of HK L-137. These results suggest that HK L-137 reduces intestinal permeability partly through activating the ERK pathway and increasing expression of the ZO-1 gene and protein. Enhancement of intestinal barrier function with HK L-137 might be effective in preventing and treating leaky gut, for which no specific therapeutic tool has been established.

Interactions between Age-Related Type 2 Diabetes and the Small Intestine.

The number of patients with type 2 diabetes is increasing worldwide. The mechanisms leading to type 2 diabetes and its complications is being researched; however, the pathological mechanisms of diabetes in the small intestine remain unclear. Therefore, we examined these pathological mechanisms in the small intestine using a mouse model of type 2 diabetes (KK-Ay/TaJcl) aged 10 and 50 weeks. The results showed that diabetes worsened with age in the mice with type 2 diabetes. In these mice, advanced glycation end products (AGEs) in the small intestine and mast cell expression increased, whereas diamine oxidase (DAO) decreased; increased tumor necrosis factor (TNF)-α and histamine levels in the plasma and small intestine were also detected. Additionally, the expression of zonula occludens (ZO)-1 and Claudin1 and cell adhesion molecules in the small intestine reduced. These results exacerbated with age. These findings indicate that type 2 diabetes causes AGE/mast cell/histamine and TNF-α signal transmission in the small intestine and decreases small intestinal wall cell adhesion molecules cause TNF-α and histamine to flow into the body, worsening the diabetic condition. In addition, this sequence of events is suggested to be strengthened in aged mice with type 2 diabetes, thus exacerbating the disease. These findings of this study may facilitate the elucidation of the pathological mechanisms of type 2 diabetes and its associated complications.

Indole-3-carboxyaldehyde does not reverse the intestinal effects of fiber-free diet in mice.

Objective: Fiber-free diet impairs intestinal and colonic health in mice, in parallel with a reduction in glucagon like peptide-1 (GLP-1) levels. Endogenous GLP-1 is important for intestinal growth and maintenance of the intestinal integrity. We aimed to investigate whether fiber-free diet reduces luminal content of metabolites which, upon supplementation, could increase GLP-1 secretion and restore the adverse effects of fiber-free diet. Methods: Untargeted metabolomics (LC-MS) was performed on colonic content of mice fed a fiber-free diet, identifying a metabolite of particular interest: indole-3-carboxyaldehyde (I3A). We exposed cultured GLUTag cells to I3A, and measured cumulative GLP-1 secretion. Isolated colon perfusions were performed in male C57BL/6JRj mice and Wistar rats. I3A was administered luminally or vascularly, and GLP-1 was measured in portal vein effluent. Finally, female C57BL/6JRJ mice were fed chow or fiber-free diet, with I3A or vehicle by oral gavage. After 10 days, plasma GLP-1 (ELISA) and intestinal permeability (FITC-dextran) were measured, animals were sacrificed and organs removed for histology. Results: Mice fed a fiber-free diet had significantly lower I3A in their colonic content compared to a control diet (7883 ± 3375 AU, p=0.04). GLP-1 secretion from GLUTag cells was unchanged after five minutes of exposure to I3A. However, GLP-1 levels increased after 120 minutes of exposure to 1 mM (60% increase, p=0.016) and 5 mM (89% increase, p=0.0025) I3A. In contrast, 48 h exposure to 1 mM decreased GLP-1 secretion (51% decrease, p<0.001) and viability. In isolated perfused mouse and rat colon, I3A applied into the luminal or vascular side did not affect GLP-1 secretion. Mice fed a fiber-free diet tended to weigh less compared to chow fed mice; and the small intestine and colon were significantly smaller. No differences were seen in crypt depth, villus length, mucosal area, and intestinal permeability. Supplementing I3A did not affect body weight, morphology or plasma GLP-1 levels. Conclusions: Fiber-free diet lowered colonic content of I3A in mice. I3A stimulates GLP-1 secretion in vitro, but not in animal studies. Moreover, it has no evident beneficial effect on intestinal health when administered in vivo.

Hyperspectral imaging combined with blood oxygen saturation for in vivo analysis of small intestinal necrosis tissue.

Acute mesenteric ischemia (AMI) is a clinically significant vascular and gastrointestinal condition, which is closely related to the blood supply of the small intestine. Unfortunately, it is still challenging to properly discriminate small intestinal tissues with different degrees of ischemia. In this study, hyperspectral imaging (HSI) was used to construct pseudo-color images of oxygen saturation about small intestinal tissues and to discriminate different degrees of ischemia. First, several small intestine tissue models of New Zealand white rabbits were prepared and collected their hyperspectral data. Then, a set of isosbestic points were used to linearly transform the measurement data twice to match the reference spectra of oxyhemoglobin and deoxyhemoglobin, respectively. The oxygen saturation was measured at the characteristic peak band of oxyhemoglobin (560 nm). Ultimately, using the oxygenated hemoglobin reflectance spectrum as the benchmark, we obtained the relative amount of median oxygen saturation in normal tissues was 70.0 %, the IQR was 10.1 %, the relative amount of median oxygen saturation in ischemic tissues was 49.6 %, and the IQR was 14.6 %. The results demonstrate that HSI combined with the oxygen saturation computation method can efficiently differentiate between normal and ischemic regions of the small intestinal tissues. This technique provides a powerful support for internist to discriminate small bowel tissues with different degrees of ischemia, and also provides a new way of thinking for the diagnosis of AMI.

Glyphosate-induced changes in the expression of galanin and GALR1, GALR2 and GALR3 receptors in the porcine small intestine wall.

Glyphosate is the active ingredient of glyphosate-based herbicides and the most commonly used pesticide in the world. The goal of the present study was to verify whether low doses of glyphosate (equivalent to the environmental exposure) evoke changes in galanin expression in intramural neurons in the small intestine in pigs and to quantitatively determine changes in the level of galanin receptor encoding mRNA (GALR1, GALR2, GALR3) in the small intestine wall. The experiment was conducted on 15 sexually immature gilts divided into three study groups: control (C)-animals receiving empty gelatin capsules; experimental 1 (G1)-animals receiving a low dose of glyphosate (0.05 mg/kg b.w./day); experimental 2 (G2)-animals receiving a higher dose of glyphosate (0.5 mg/kg b.w./day) orally in gelatine capsules for 28 days. Glyphosate ingestion led to an increase in the number of GAL-like immunoreactive intramural neurons in the porcine small intestine. The results of RT-PCR showed a significant increase in the expression of mRNA, which encodes the GAL-receptors in the ileum, a decreased expression in the duodenum and no significant changes in the jejunum. Additionally, intoxication with glyphosate increased the expression of SOD2-encoding mRNA in the duodenum and decreased it in the jejunum and ileum, but it did not affect SOD1 expression. The results suggest that it may be a consequence of the cytotoxic and/or neurotoxic properties of glyphosate and/or its ability to induce oxidative stress.

Spatial Proteomics Reveals Alcohol-Induced Damages to the Crypts and Villi of the Mouse Small Intestine.

Alcohol consumption perturbs the gut immune barrier and ultimately results in alcoholic liver diseases, but little is known about how immune-related cells in the gut are perturbed in this process. In this study, we employed laser capture microdissection and a label-free proteomics approach to investigate the consequences of alcohol exposure to the proteomes of crypts and villi in the proximal small intestine. Intestinal tissues from alcohol-fed and pair-fed mice were microdissected to selectively capture cells in the crypts and villi regions, followed by one-pot protein digestion and data-independent LC-MS/MS analysis. We successfully identified over 3000 proteins from each of the crypt or villi regions equivalent to ∼3000 cells. Analysis of alcohol-treated tissues indicated an enhanced alcohol metabolism and reduced levels of α-defensins in crypts, alongside increased lipid metabolism and apoptosis in villi. Immunofluorescence imaging further corroborated the proteomic findings. Our work provides a detailed profiling of the proteomic changes in the compartments of the mouse small intestine and aids in molecular-level understanding of alcohol-induced tissue damage.

Dietary Hemin Remodels Gut Microbiota and Mediates Tissue Inflammation and Injury in the Small Intestine.

SCOPE: Epidemiological studies have linked excessive red and processed meat intake to gut disorders. Under laboratory conditions, high heme content is considered the primary health risk factor for red meat. However, heme in meat is present in myoglobin, which is an indigestible protein, suggesting the different functions between myoglobin and heme. This study aims to explore how dietary myoglobin and heme affect gut health and microbiota differently. METHODS AND RESULTS: Histological and biochemical assessments as well as 16S rRNA sequencing are performed. Moderate myoglobin intake (equivalent to the recommended intake of 150 g meat per day for human) has beneficial effects on the duodenal barrier. However, a too high myoglobin diet (equivalent to intake of 3000 g meat per day for human) triggers duodenum injury and alters the microbial community. The hemin diet destroys intestinal tissue and ileal microbiota more significantly. The in vitro experiments further confirm that free heme exhibits high toxicity to beneficial gut bacteria while myoglobin promotes the growth and metabolism of Limosilactobacillus reuteri. CONCLUSION: Moderate intake of myoglobin or hemin is beneficial to intestinal health and microbiota, but too high amounts lead to tissue inflammation and injury in the small intestine by reshaping ileal microbiota.

Mucoadhesive polymers: Design of S-protected thiolated cyclodextrin-based hydrogels.

AIM: This study aims to design chemically crosslinked thiolated cyclodextrin-based hydrogels and to evaluate their mucoadhesive properties via mucosal residence time studies on porcine small intestinal mucosa and on porcine buccal mucosa. METHODS: Free thiol groups of heptakis(6-deoxy-6-thio)-ß-cyclodextrin (ß-CD-SH) were S-protected with 2-mercaptoethanesulfonic acid (MESNA) followed by crosslinking with citric acid. Cytotoxicity was assessed by hemolysis as well as resazurin assay. Hydrogels were characterized by their rheological and mucoadhesive properties. Ritonavir was employed as model drug for in vitro release studies from these hydrogels. RESULTS: The structure of S-protected ß-CD-SH was confirmed by IR and 1H NMR spectroscopy. Degree of thiolation was 390 ± 7 µmol/g. Hydrogels based on native ß-CD showed hemolysis of 12.5 ± 2.5 % and 13.6 ± 2.7 % within 1 and 3 h, whereas hemolysis of just 3.5 ± 2.8 % and 3.9 ± 3.0 % was observed for the S-protected thiolated CD hydrogels, respectively. Both native and S-protected thiolated hydrogels showed minor cytotoxicity on Caco-2 cells. Rheological investigations of S-protected thiolated ß-CD-based hydrogel (16.2 % m/v) showed an up to 13-fold increase in viscosity in contrast to the corresponding native ß-CD-based hydrogel. Mucosal residence time studies showed that thiolated ß-CD-based hydrogel is removed to a 16.6- and 2.4-fold lower extent from porcine small intestinal mucosa and porcine buccal mucosa in comparision to the native ß-CD-based hydrogel, respectively. Furthermore, a sustained release of ritonavir from S-protected thiolated ß-CD-based hydrogels was observed. CONCLUSION: Because of their comparatively high mucoadhesive and release-controlling properties, S-protected thiolated ß-CD-based hydrogels might be promising systems for mucosal drug delivery.

Integrated transcriptomics and metabolomics reveal the mechanism of intestinal damage upon acute patulin exposure in mice.

Mycotoxin contamination has become a major food safety issue and greatly threatens human and animal health. Patulin (PAT), a common mycotoxin in the environment, is exposed through the food chain and damages the gastrointestinal tract. However, its mechanism of enterotoxicity at the genetic and metabolic levels remains to be elucidated. Herein, the intestinal histopathological and biochemical indices, transcriptome, and metabolome of C57BL/6 J mice exposed to different doses of PAT were successively assessed, as well as the toxicokinetics of PAT in vivo. The results showed that acute PAT exposure induced damaged villi and crypts, reduced mucus secretion, decreased SOD and GSH-Px activities, and enhanced MPO activity in the small intestine and mild damage in the colon. At the transcriptional level, the genes affected by PAT were dose-dependently altered in the small intestine and fluctuated in the colon. PAT primarily affected inflammation-related signaling pathways and oxidative phosphorylation in the small intestine and immune responses in the colon. At the metabolic level, amino acids decreased, and extensive lipids accumulated in the small intestine and colon. Seven metabolic pathways were jointly affected by PAT in two intestinal sites. Moreover, changes in PAT products and GST activity were detected in the small intestinal tissue but not in the colonic tissue, explaining the different damage degrees of the two sites. Finally, the integrated results collectively explained the toxicological mechanism of PAT, which damaged the small intestine directly and the colon indirectly. These results paint a clear panorama of intestinal changes after PAT exposure and provide valuable information on the exposure risk and toxic mechanism of PAT.

A MTA2-SATB2 chromatin complex restrains colonic plasticity toward small intestine by retaining HNF4A at colonic chromatin.

Plasticity among cell lineages is a fundamental, but poorly understood, property of regenerative tissues. In the gut tube, the small intestine absorbs nutrients, whereas the colon absorbs electrolytes. In a striking display of inherent plasticity, adult colonic mucosa lacking the chromatin factor SATB2 is converted to small intestine. Using proteomics and CRISPR-Cas9 screening, we identify MTA2 as a crucial component of the molecular machinery that, together with SATB2, restrains colonic plasticity. MTA2 loss in the adult mouse colon activated lipid absorptive genes and functional lipid uptake. Mechanistically, MTA2 co-occupies DNA with HNF4A, an activating pan-intestinal transcription factor (TF), on colonic chromatin. MTA2 loss leads to HNF4A release from colonic chromatin, and accumulation on small intestinal chromatin. SATB2 similarly restrains colonic plasticity through an HNF4A-dependent mechanism. Our study provides a generalizable model of lineage plasticity in which broadly-expressed TFs are retained on tissue-specific enhancers to maintain cell identity and prevent activation of alternative lineages, and their release unleashes plasticity.

LPA5-Dependent signaling regulates regeneration of the intestinal epithelium following irradiation.

Lysophosphatidic acid (LPA) is a bioactive lipid molecule that regulates a wide array of cellular functions, including proliferation, differentiation, and survival, via activation of cognate receptors. The LPA5 receptor is highly expressed in the intestinal epithelium, but its function in restoring intestinal epithelial integrity following injury has not been examined. Here, we use a radiation-induced injury model to study the role of LPA5 in regulating intestinal epithelial regeneration. Control mice (Lpar5f/f) and mice with an inducible, epithelial cell-specific deletion of Lpar5 in the small intestine (Lpar5IECKO) were subjected to 10 Gy total body X-ray irradiation and analyzed during recovery. Repair of the intestinal mucosa was delayed in Lpar5IECKO mice with reduced epithelial proliferation and increased crypt cell apoptosis. These effects were accompanied by reduced numbers of OLFM4+ intestinal stem cells (ISCs). The effects of LPA5 on ISCs were corroborated by studies using organoids derived from Lgr5-lineage tracking reporter mice with deletion of Lpar5 in Lgr5+-stem cells (Lgr5Cont or Lgr5ΔLpar5). Irradiation of organoids resulted in fewer numbers of Lgr5ΔLpar5 organoids retaining Lgr5+-derived progenitor cells compared with Lgr5Cont organoids. Finally, we observed that impaired regeneration in Lpar5IECKO mice was associated with reduced numbers of Paneth cells and decreased expression of Yes-associated protein (YAP), a critical factor for intestinal epithelial repair. Our study highlights a novel role for LPA5 in regeneration of the intestinal epithelium following irradiation and its effect on the maintenance of Paneth cells that support the stem cell niche.NEW & NOTEWORTHY We used mice lacking expression of the lysophosphatidic acid receptor 5 (LPA5) in intestinal epithelial cells and intestinal organoids to show that the LPA5 receptor protects intestinal stem cells and progenitors from radiation-induced injury. We show that LPA5 induces YAP signaling and regulates Paneth cells.

TLR7-dependent eosinophil degranulation links psoriatic skin inflammation to small intestinal inflammatory changes in mice.

Recent evidence of gut microbiota dysbiosis in the context of psoriasis and the increased cooccurrence of inflammatory bowel disease and psoriasis suggest a close relationship between skin and gut immune responses. Using a mouse model of psoriasis induced by the Toll-like receptor (TLR) 7 ligand imiquimod, we found that psoriatic dermatitis was accompanied by inflammatory changes in the small intestine associated with eosinophil degranulation, which impaired intestinal barrier integrity. Inflammatory responses in the skin and small intestine were increased in mice prone to eosinophil degranulation. Caco-2 human intestinal epithelial cells were treated with media containing eosinophil granule proteins and exhibited signs of inflammation and damage. Imiquimod-induced skin and intestinal changes were attenuated in eosinophil-deficient mice, and this attenuation was counteracted by the transfer of eosinophils. Imiquimod levels and the distribution of eosinophils were positively correlated in the intestine. TLR7-deficient mice did not exhibit intestinal eosinophil degranulation but did exhibit attenuated inflammation in the skin and small intestine following imiquimod administration. These results suggest that TLR7-dependent bidirectional skin-to-gut communication occurs in psoriatic inflammation and that inflammatory changes in the intestine can accelerate psoriasis.