Intestinal Epithelial Cells Research Articles

The Intestinal Transporter SLC30A1 Plays a Critical Role in Regulating Systemic Zinc Homeostasis.

The essential trace element, zinc, regulates virtually all aspects of cellular physiology, particularly cell proliferation and survival. Diverse families of metal transporters, metallothioneins, and metal-responsive transcriptional regulators are linked to zinc homeostasis. However, the mechanism underlying the regulation of systemic zinc homeostasis remains largely unknown. Here, it is reported that the intestinal transporter SLC30A1 plays an essential role in maintaining systemic zinc homeostasis. Using several lines of tissue-specific knockout mice, it is found that intestinal Slc30a1 plays a critical role in survival. Furthermore, lineage tracing reveals that Slc30a1 is localized to the basolateral membrane of intestinal epithelial cells (IECs). It is also found that Slc30a1 safeguards both intestinal barrier integrity and systemic zinc homeostasis. Finally, an integrative analysis of the cryo-EM structure and site-specific mutagenesis of human SLC30A1 are performed and a zinc transport mechanism of SLC30A1 unique within the SLC30A family, with His43 serving as a critical residue for zinc selectivity, is identified.

Hyperosmotic Stress Induces the Expression of Organic Osmolyte Transporters in Porcine Intestinal Cells and Betaine Exerts a Protective Effect on the Barrier Function.

Background/objectives: The porcine intestinal epithelium plays a fundamental role as a defence interface against pathogens. Its alteration can cause severe inflammatory conditions and diseases. Hyperosmotic stress under physiological conditions and upon pathogen challenge can cause malabsorption. Different cell types counteract the osmolarity increase by accumulating organic osmolytes such as betaine, taurine, and myo-inositol through specific transporters. Betaine is known for protecting cells from hyperosmotic stress and has positive effects when fed to pigs. The aim of this study is to demonstrate the modulation of osmolyte transporters gene expression in IPEC-J2 during osmolarity changes and assess the effects of betaine. Methods: IPEC-J2 were seeded in transwells, where differentiate as a polarized monolayer. Epithelial cell integrity (TEER), oxidative stress (NO) and gene expression of osmolyte transporters, tight junction proteins (TJp) and pro-inflammatory cytokines were evaluated. Results: Cells treated with NaCl hyperosmolar medium (500 mOsm/L) showed a TEER decrease at 3 h and detachment within 24 h, associated with an osmolyte transporters reduction. IPEC-J2 treated with mannitol hyperosmolar medium (500 mOsm/L) upregulated taurine (TauT), myo-inositol (SMIT) and betaine (BGT1) transporters expression. A decrease in TJp expression was associated with a TEER decrease and an increase in TNFα, IL6, and IL8. Betaine could attenuate the hyperosmolarity-induced reduction in TEER and TJp expression, the NO increase and cytokines upregulation. Conclusions: This study demonstrates the expression of osmolyte transporters in IPEC-J2, which was upregulated upon hyperosmotic treatment. Betaine counteracts changes in intracellular osmolarity by contributing to maintaining the epithelial barrier function and reducing the inflammatory condition. Compatible osmolytes may provide beneficial effects in therapies for diseases characterized by inflammation and TJp-related dysfunctions.

Evaluation of the immunomodulatory activity of probiotics mixture and sulfasalazine against acetic acid-induced colitis in a murine model.

Currently, the use of probiotics to treat inflammatory bowel diseases (IBD) is widely accepted because of their gut microbiota modulation capabilities and anti-inflammatory potential. The aim of this study is to examine the immunomodulatory outcomes of probiotics and sulfasalazine in the acetic acid-induced colitis murine model. The animals were randomly assigned to one of the seven groups. Following the induction of colitis, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12, and sulfasalazine (SASP) were orally administered for 10 days. Subsequently, the in vitro anti-inflammatory effect on TNF-α and IL-10 in the supernatants of cultured spleen cells was assessed via ELISAs. Relative mRNA expression of ZO-1, MLCK, iNOS, TNFR2, ROR-γt, GATA-3, T-bet, and Foxp3 was determined using quantitative reverse‑transcription polymerase chain reaction (qRT‑PCR). The SASP plus probiotic mixture was more effective in alleviating colitis symptoms, and reducing disease activity scores, and mucosal inflammation. qRT-PCR analysis revealed a significant reduction in T-bet and RORγt levels, while Foxp3 and GATA-3 levels increased in the colons of colitis mice. In addition, the selected strains substantially inhibited the release of inflammatory markers. Administration of LA-5 + BB-12 + SASP resulted in considerably higher inhibition of NO production and cell proliferation than in the other groups (p < 0.001). Treatment with LA-5 + BB-12 + SASP also reduced TNF-α-mediated apoptosis in intestinal epithelial cells (IECs). Survey results highlight that the combination regimen could be a promising strategy for IBD therapy, warranting further study of its clinical application and long-term benefits.

Soybean Agglutinin Induced Apoptotic Effects by Down-Regulating ANXA2 Through FAK Pathway in IPEC-J2 Cells.

Soybean agglutinin (SBA) is an anti-nutritional factor in soybean, possesses toxic effects by binding to intestinal epithelial cells, and finally interferes the digestion and absorption of nutrients in humans and animals. Annexin A2 (ANXA2) is one of the SBA-specific binding proteins in intestinal epithelial cells and participates in multiple cellular biological processes. However, whether SBA affects apoptosis through ANXA2 and its apoptosis-related pathway remains unclear. IPEC-J2 is an ideal model to study human intestinal health. Therefore, this study aims to investigate the effects of ANXA2 on SBA-induced intestinal epithelial cell apoptosis and the related pathway mechanism using IPEC-J2 as a cell model. The results showed that SBA induced the apoptosis through FAK signal pathway and decreased the gene and protein expressions of ANXA2 in IPEC-J2. The expression of ANXA2 protein had a negative correlation with the apoptosis rates, and a positive correlation with the expression of FAK protein and FAK pathway downstream proteins. In conclusion, SBA induced apoptosis of IPEC-J2 cells by downregulating the expression of ANXA2, which activated the FAK pathway. These findings highlight the toxic mechanism of SBA, which will provide basis for studying the toxicity mechanisms of other food-derived anti-nutrients and provide a new perspective for human gastrointestinal health and related cancer treatment.

UDCA ameliorates inflammation driven EMT by inducing TGR5 dependent SOCS1 expression in mouse macrophages

Long-standing chronic inflammation of the digestive tract leads to Inflammatory Bowel Diseases (IBD), comprising Crohn’s Disease (CD) and Ulcerative colitis (UC). The persistent prevalence of these conditions in the gut is a predisposing factor for Colitis-Associated Cancer (CAC), one of the most common sub-types of Colorectal Cancer (CRC), emphasizing the role of inflammation in tumorigenesis. Therefore, targeted intervention of chronic intestinal inflammation is a potential strategy for preclusion and treatment of inflammation-driven malignancies. The association between bile acids (BA) and gut immune homeostasis has been explored in the recent past. However, the exact downstream mechanism by which secondary BA successfully regulating intestinal inflammation and inflammation-dependent CAC is unclear. Our study demonstrated that Ursodeoxycholic acid (UDCA), a secondary bile acid of host gut microbial origin, finetunes the dialogue between activated macrophages and intestinal epithelial cells, modulating inflammation-driven epithelial-mesenchymal transition (EMT), a hallmark of cancer. UDCA treatment and dependency on the TGR5/GPBAR1 receptor significantly upregulated the Suppressor of Cytokine Signaling 1 (SOCS1) expression, contributing to the regulation of pro-inflammatory cytokines in activated macrophages. In this study, we also noticed heightened expression of SOCS1 in UDCA-mitigated CAC in the AOM-DSS mouse model with reduced inflammatory gene expression. Overall, our observations highlight the possible utility of UDCA for inflammation-driven intestinal cancer.

Recombinant Lactococcus lactis secreting FliC protein nanobodies for resistance against Salmonella enteritidis invasion in the intestinal tract

Salmonella Enteritidis is a major foodborne pathogen throughout the world and the increase in antibiotic resistance of Salmonella poses a significant threat to public safety. Natural nanobodies exhibit high affinity, thermal stability, ease of production, and notably higher diversity, making them widely applicable for the treatment of viral and bacterial infections. Recombinant expression using Lactococcus lactis leverages both acid resistance and mucosal colonization properties of these bacteria, allowing the effective expression of exogenous proteins for therapeutic effects. In this study, nine specific nanobodies against the flagellar protein FliC were identified and expressed. In vitro experiments demonstrated that FliC-Nb-76 effectively inhibited the motility of S. Enteritidis and inhibited its adhesion to and invasion of HIEC-6, RAW264.7, and chicken intestinal epithelial cells. Additionally, a recombinant L. lactis strain secreting the nanobody, L. lactis-Nb76, was obtained. Animal experiments confirmed that it could significantly reduce the mortality rates of chickens infected with S. Enteritidis, together with alleviating the inflammatory response caused by the pathogen. These results provide a novel strategy for the treatment of antibiotic-resistant S. Enteritidis infection in the intestinal tract.Graphical

Investigate the metabolic changes in intestinal diseases by employing a 1H-NMR-based metabolomics approach on Caco-2 cells treated with cedrol.

Mitochondrial dysfunction may precipitate intestinal dysfunction, while inflammatory bowel disease manifests as a chronic inflammatory ailment affecting the gastrointestinal tract. This condition disrupts the barrier function of the intestinal epithelium and alters metabolic products. Increasing mitochondrial adenosine triphosphate (ATP) synthesis in intestinal epithelial cells presents a promising avenue for colitis treatments. Nevertheless, the impact of cedrol on ATP and the intestinal barrier remains unexplored. Hence, this study is dedicated to examining the cedrol's protective effect on an inflammatory cocktail (IC)-induced intestinal epithelial barrier dysfunction in Caco-2 cells. The finding reveals that cedrol enhances ATP content and the transepithelial electrical resistance value in the intestinal epithelial barrier. Moreover, cedrol mitigates the IC-induced decrease in the messenger ribonucleic acid (mRNA)expression of tight junction proteins (ZO-1, Occludin, and Claudin-1), thereby ameliorating intestinal epithelial barrier dysfunction. Furthermore, nuclear magnetic resonance (NMR)-based metabolomic analysis indicated that IC-exposed Caco-2 cells are restored by cedrol treatments. Notably, cedrol elevates metabolites such as amino acids, thereby enhancing the intestinal barrier. In conclusion, cedrol alleviates IC-induced intestinal epithelial barrier dysfunction by promoting ATP-dependent proliferation of Caco-2 cells and bolstering amino acid levels to sustain tight junction messenger ribonucleic acid expression.

Development of the infant’s microbiota depending on the nature of feeding: A review

Breast milk oligosaccharides (BMOs) are short polymers of simple sugars that are present in high concentrations in a woman’s breast milk (BM). Their content changes fast over time. Genetic factors, the duration of lactation, and environmental factors particularly influence the level of BMOs. BMOs can facilitate the development of the immune system and protect against infectious diseases directly through the interaction of intestinal epithelial cells or indirectly through the modulation of the intestinal microbiota, including stimulating Bifidobacterium growth. Clinical data suggest that adding BMOs to infant formula promotes normal neonatal growth and benefits infant health. Adding 1 or 2 BMOs to infant formulas is safe and brings their composition closer to the BM, allowing the child to develop harmoniously.

Fucosylation of glycoproteins and glycolipids: opposing roles in cholera intoxication.

Cholera toxin (CT) is the etiological agent of cholera. Here we report that multiple classes of fucosylated glycoconjugates function in CT binding and intoxication of intestinal epithelial cells. In Colo205 cells, knockout (KO) of B3GNT5, which encodes an enzyme required for synthesis of lacto and neolacto series glycosphingolipids (GSLs), reduces CT binding but sensitizes cells to intoxication. Overexpressing B3GNT5 to generate more fucosylated GSLs confers protection against intoxication, indicating that fucosylated GSLs act as decoy receptors for CT. KO of B3GALT5 causes increased production of fucosylated O-linked and N-linked glycoproteins and leads to increased CT binding and intoxication. KO of B3GNT5 in B3GALT5-KO cells eliminates production of fucosylated GSLs but increases intoxication, identifying fucosylated glycoproteins as functional receptors for CT. These findings provide insight into the molecular determinants regulating CT sensitivity of host cells.

Intestinal-Target and Glucose-Responsive Smart Hydrogel toward Oral Delivery System of Drug with Improved Insulin Utilization.

An intelligent insulin delivery system targeting intestinal absorption and glucose responsiveness can enhance the bioavailability through oral insulin therapy, offering promising diabetes treatment. In this paper, a glucose and pH dual-response polymer hydrogel using carboxymethyl agarose modified with 3-amino-phenylboronic acid and l-valine (CPL) was developed as an insulin delivery carrier, exhibiting excellent biocompatibility and effective insulin encapsulation. The insulin encapsulated in the hydrogel (Ins-CPL) was released in a controlled manner in response to the in vivo stimulation of blood glucose and pH levels with higher levels of intracellular uptake and utilization of insulin in the intestinal environment simultaneously. Notably, the Ins-CPL hydrogel effectively regulated blood sugar in diabetic rats over a long period by simulating endogenous insulin, responding to changes in plasma pH and glucose levels, and overcoming the intestinal epithelium barrier. This indicates a significant boost in oral insulin bioavailability and broadens its application prospects.

Parasites and Microbiota: Dual Interactions and Therapeutic Perspectives

The human gut hosts a diverse and active community of bacteria that symbiotically support the physiology, metabolism, and immunity of the intestinal lining. Nevertheless, a dynamic community of parasites (helminths and protozoa) may share a habitat with gut-dwelling microbiota. Both microbiota and parasites can significantly change the physical and immunological environment of the gut, thus generating several mechanisms of interaction. Studying this field is crucial for understanding the pathogenesis of parasitic diseases. Additionally, intestinal microbiota and gut-dwelling parasites may interact with each other and with the host immunity to alleviate or exacerbate the disease. These interactions can alter the pathogenicity of both parasites and microbiota, thereby changing the infection outcomes and the overall disease profile. Parasites and microbiota interactions occur via several mechanisms, including physical alteration in both the gastrointestinal microenvironment and the adaptive and innate immune responses. By modulating the microbiota, treating parasitic infections and microbiota dysbiosis may be improved through knowing the mechanisms and consequences of the interactions between intestinal parasites and the microbiota. Thus, new biological tools of treatment including probiotics can be introduced, particularly with the emergence of drug resistance and adverse effects.

Pathogenic diversification of the gut commensal Providencia alcalifaciens via acquisition of a second type III secretion system.

Providencia alcalifaciens is a Gram-negative bacterium found in various water and land environments and organisms, including insects and mammals. Some P. alcalifaciens strains encode gene homologs of virulence factors found in pathogenic Enterobacterales members, such as Salmonella enterica serovar Typhimurium and Shigella flexneri. Whether these genes are pathogenic determinants in P. alcalifaciens is not known. In this study, we investigated P. alcalifaciens-host interactions at the cellular level, focusing on the role of two type III secretion systems (T3SS) belonging to the Inv-Mxi/Spa family. T3SS1b is widespread in Providencia spp. and encoded on the chromosome. A large plasmid that is present in a subset of P. alcalifaciens strains, primarily isolated from diarrheal patients, encodes for T3SS1a. We show that P. alcalifaciens 205/92 is internalized into eukaryotic cells, lyses its internalization vacuole, and proliferates in the cytosol. This triggers caspase-4-dependent inflammasome responses in gut epithelial cells. The requirement for the T3SS1a in entry, vacuole lysis, and cytosolic proliferation is host cell type-specific, playing a more prominent role in intestinal epithelial cells than in macrophages or insect cells. In a bovine ligated intestinal loop model, P. alcalifaciens colonizes the intestinal mucosa and induces mild epithelial damage with negligible fluid accumulation in a T3SS1a- and T3SS1b-independent manner. However, T3SS1b was required for the rapid killing of Drosophila melanogaster. We propose that the acquisition of two T3SS has allowed P. alcalifaciens to diversify its host range, from a highly virulent pathogen of insects to an opportunistic gastrointestinal pathogen of animals.

Host cell-specific metabolism of linoleic acid controls Toxoplasma gondii growth in cell culture.

The obligate intracellular parasite Toxoplasma gondii can infect and replicate in any warm-blooded cell tested to date, but much of our knowledge about T. gondii cell biology comes from just one host cell type: human foreskin fibroblasts (HFFs). To expand our knowledge of host-parasite lipid interactions, we studied T. gondii in intestinal epithelial cells, the first site of host-parasite contact following oral infection and the exclusive site of parasite sexual development in feline hosts. We found that highly metabolic Caco-2 cells are permissive to T. gondii growth even when treated with high levels of linoleic acid (LA), a polyunsaturated fatty acid (PUFA) that kills parasites in HFFs. Caco-2 cells appear to sequester LA away from the parasite, preventing membrane disruptions and lipotoxicity that characterize LA-induced parasite death in HFFs. Our work is an important step toward understanding host-parasite interactions in feline intestinal epithelial cells, an understudied but important cell type in the T. gondii life cycle.

Inflammasome-mediated pyroptosis in defense against pathogenic bacteria.

Macrophages, neutrophils, and epithelial cells are pivotal components of the host's immune response against bacterial infections. These cells employ inflammasomes to detect various microbial stimuli during infection, triggering an inflammatory response aimed at eradicating the pathogens. Among these inflammatory responses, pyroptosis, a lytic form of cell death, plays a crucial role in eliminating replicating bacteria and recruiting immune cells to combat the invading pathogen. The immunological function of pyroptosis varies across macrophages, neutrophils, and epithelial cells, aligning with their specific roles within the innate immune system. This review centers on elucidating the role of pyroptosis in resisting gram-negative bacterial infections, with a particular focus on the mechanisms at play in macrophages, neutrophils, and intestinal epithelial cells. Additionally, we underscore the cell type-specific roles of pyroptosis invivo in these contexts during defense.

Multifunctional MnGA Nanozymes for the Treatment of Ulcerative Colitis by Reducing Intestinal Inflammation and Regulating the Intestinal Flora.

In ulcerative colitis (UC), the formation of an inflammatory environment is due to the combined effects of excess production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), overproduction of proinflammatory cytokines, and disruption of immune system function. There are many kinds of traditional drugs for the clinical treatment of UC, but long-term drug use can cause toxic side effects and drug resistance and can also reduce patient compliance and other drawbacks. Hence, in light of the clinical challenges associated with UC, including the limitations of existing treatments, intense adverse reactions and the development of resistance to medications, no novel therapeutic agents that offer effective relief and maintain a high level of biosafety are urgently needed. Although many anti-inflammatory nanomedicines have been developed by researchers, the development of efficient and nontoxic nanomedicines is still a major challenge in clinical medicine. Using the natural product gallic acid and the metal compound manganese chloride, a highly effective and nontoxic multifunctional nanoenzyme was developed for the treatment of UC. Nanozymes can effectively eliminate ROS and RNS to reduce the inflammation of intestinal epithelial cells caused by oxidation, facilitate the restoration of the intestinal epithelial barrier through the upregulation of tight junction protein expression, and balance the intestinal microbiota to maintain the stability of the intestinal environment. Using a rodent model designed to mimic UC, we monitored body weight, colon length, the spleen index, and the degree of tissue damage and demonstrated that manganese gallate (MnGA) nanoparticles can reduce intestinal inflammation by clearing ROS and active nitrogen. Intestinal flora sequencing revealed that MnGA nanoparticles could regulate the intestinal flora, promote the growth of beneficial bacteria and decrease the levels of detrimental bacteria within the intestinal tract in a mouse model of UC. Thus, MnGA nanoparticles can maintain the balance of the intestinal flora. This study demonstrated that MnGA nanoparticles are excellent antioxidant and effective anti-inflammatory agents, have good biosafety, and can effectively treat UC.

ChiA: a major player in the virulence of Crohn’s disease-associated adherent and invasive Escherichia coli (AIEC)

ABSTRACT We investigated the role of ChiA and its associated polymorphisms in the interaction between Crohn’s disease (CD)-associated adherent-invasive Escherichia coli (AIEC) and intestinal mucosa. We observed a higher abundance of chiA among the metagenome of CD patients compared to healthy subjects. In dextran sulfate sodium-induced colitis mice model, AIEC-LF82∆chiA colonization was reduced in ileal, colonic and fecal samples compared to wild-type LF82. The binding of ChiA to recombinant human CHI3L1 or mucus was higher with the pathogenic polymorphism. The strength of ChiA-mucin interaction was 300-fold stronger than ChiA-rhCHI3L1. ChiA was able to degrade mucin to promote its growth and enabled LF82 to get closer to epithelial cells. The pathogenic polymorphism of ChiA had a stronger impact on mucus degradation than on the binding capability of AIEC to adhere to the intestinal epithelium. We observed that ChiA could favor an efficient bacterial invasion of intestinal crypts, and that ChiA, especially its pathogenic polymorphism, gives LF82 an advantage to uptake within Peyer’s patches, macrophages and mesenteric lymph nodes. All together, these data support the role of ChiA in the virulence of AIEC and show that it could be a promising target to reduce AIEC colonization in patients with CD.

Dietary titanium dioxide nanoparticles impair intestinal epithelial regeneration by perturbating the function of intestinal stem cells

Intestinal health is closely linked to intestinal stem cells (ISCs), which are highly sensitive to the harmful substances in the lumen. However, there is limited knowledge regarding the effects of food additives on ISCs. This study aims to investigate the impact of dietary titanium dioxide nanoparticles (TiO2 NPs) compared with titanium dioxide microparticles (TiO2 MPs) on intestinal health associated with ISCs in response to dextran sodium sulfate (DSS)-induced enteritis in mice, as well as the related mechanism. We found that exposure to 1% (w/w) TiO2 NPs aggravated DSS-induced enteritis in mice, while this effect could not be observed under exposure to TiO2 MPs. Additionally, 1% (w/w) TiO2 NPs exposure under DSS-induced enteritis worsened the ISC-mediated regeneration of intestinal epithelium by decreasing the epithelial cell proliferation and epithelial turnover rate while increasing epithelial cell death. Meanwhile, using a 3D intestinal organoid model, we discovered that 20 μg/mL TiO2 NPs impaired ISC function and disrupted ISC fate specification both ex vivo and in vitro. Furthermore, TiO2 NPs hindered the nuclear translocation of β-catenin, reducing the overall output of Wnt signaling. Together, TiO2 NPs deteriorated the intestinal epithelial regeneration of mice with DSS-induced enteritis by perturbating ISC function and fate specification through a mechanism involving Wnt signaling. These findings highlight the adverse effect of dietary TiO2 NPs on ISCs and shed light on the particle size optimization of TiO2 food additive.

Lipid-lowering and antioxidant properties of probiotic Bifidobacterium animalis MSMC83 in rats on a high-fat diet.

Hyperlipidaemia, the abnormally high concentration of lipids such as cholesterol in the body, has a series of deleterious effects on health that are least in part are due to increased inflammation and oxidative stress. Probiotics are living microorganisms that possess the efficacy to improve health. Among the many effects that have been ascribed to probiotics is the potential to lower the body lipid content. Here, we used a rat model of induced hyperlipidaemia to assess the lipid-lowering and antioxidant properties of the probiotic strain Bifidobacterium animalis MSMC83 as well as its impact on intestinal barrier immunity and the intestinal microbiota. Oral probiotic intake led to a reduction of body weight, fasting blood glucose, and lipid levels, and increased expression of cholesterol-7α-hydroxylase and antioxidant enzymes. Additionally, B. animalis MSMC83 decreased the levels of liver enzymes and pro-inflammatory cytokines, leading to reduced hepatic steatosis. Furthermore, it re-established intestinal barrier integrity as shown by restoration of the tight junction protein zonula occludens-1 amount and reduced pathogen-induced inflammation in the intestinal epithelium as shown by readjusted expression of toll-like receptors (TLRs). Moreover B. animalis MSMC83 contributed to the maintenance of a balanced, diverse microbiome. Thus, our results indicate that B. animalis MSMC83 alleviates risk factors associated with hyperlipidaemia, suggesting its use as a probiotic to counter the effects associated with unhealthy diets.

Assessing nanotoxicity of food-relevant particles: A comparative analysis of cellular responses in cell monolayers versus 3D gut epithelial cultures

Engineered nanoparticles (NPs) are extensively used in the food industry, yet safety concerns remain. The lack of validated methodologies is a bottleneck towards resolving this uncertainty. Hence, the current study aims to compare two cell models by examining the toxicological impacts of two food-relevant NPs (SiO2 and Ag) on intestinal epithelia using monolayer Caco-2 cells and full-thickness 3D tissue models of human small intestines (EpiIntestinal™). Comprehensive characterization and dosimetric analysis of the NPs were performed to determine effective doses and model realistic exposures. Neither genotoxicity nor cytotoxicity were detected in the 3D tissues after NP treatment, while the 2D cultures exhibited cytotoxic response from Ag NP treatment for 24 h at 1 μg/ml. Hyperspectral imaging and transmission electron microscopy confirmed uptake of both NPs by cells in both 2D and 3D culture models. Ag NPs caused an increase in autophagy, whereas SiO2 NPs induced increased cytoplasmic vacuolization. Based on realistic exposure levels studied, the 3D small intestinal tissue model was found to be more resilient to NP treatment compared to 2D cell monolayers. This comparative approach towards toxicological assessment of food relevant NPs could be used as a framework for future analysis of NP behavior and nanotoxicity in the gut.

Mannose coated selenium nanoparticles normalize intestinal homeostasis in mice and mitigate colitis by inhibiting NF-κB activation and enhancing glutathione peroxidase expression

Impaired intestinal homeostasis is a major pathological feature of inflammatory bowel diseases (IBD). Mannose and selenium (Se) both demonstrate potential anti-inflammatory and anti-oxidative properties. However, most lectin receptors bind free monosaccharide ligands with relatively low affinity and most Se species induce side effects beyond a very narrow range of dosage. This has contributed to a poorly explored therapies for IBD that combine mannose and Se to target intestinal epithelial cells (IECs) for normalization gut homeostasis. Herein, a facile and safe strategy for ulcerative colitis (UC) treatment was developed using optimized, mannose-functionalized Se nanoparticles (M-SeNPs) encapsulated within a colon-targeted hydrogel delivery system containing alginate (SA) and chitosan (CS). This biocompatible nanosystem was efficiently taken up by IECs and led to increased expression of Se-dependent glutathione peroxidases (GPXs), thereby modulating IECs’ immune response. Using a mouse model of DSS-induced colitis, (CS/SA)-embedding M-SeNPs (C/S-MSe) were found to mitigate oxidative stress and inflammation through the inhibition of the NF-kB pathway in the colon. This stabilized mucosal homeostasis of IECs and ameliorated colitis-related symptoms, thereby providing a potential new approach for treatment of IBD.