Search Results (84)

Background: Chronic enteropathy associated with the SLCO2A1 gene (CEAS) is a rare disease characterized by multiple small intestinal ulcers whose pathogenesis remains poorly understood. This study aimed to characterize the proteomic and phosphoproteomic profiles of CEAS and to identify molecular pathways involved in its pathogenesis. Methods: Quantitative proteomics and phosphoproteomics were performed on intestinal mucosal tissues from patients with CEAS (n = 3), Crohn’s disease (CD, n = 3), and healthy controls (n = 3). Differentially expressed proteins (DEPs) and differentially phosphorylated proteins (DPPs) were analyzed using functional enrichment, gene set enrichment analysis (GSEA), protein–protein interaction (PPI) networks, and integrative analysis. Results: A total of 900 DEPs were identified in CEAS and 277 in CD relative to controls, including 717 CEAS-specific proteins. CEAS-specific alterations were strongly enriched in focal adhesion and extracellular matrix-related pathways, whereas shared proteins between CEAS and CD were primarily associated with epithelial barrier function, including tight junction and adherens junction pathways. GSEA revealed that CEAS was characterized by upregulation of tissue remodeling and focal adhesion pathways, accompanied by suppression of digestive and metabolic processes, while CD exhibited prominent adaptive immune activation. PPI network analysis identified POSTN, CDH1, TLN1, and VIM as candidate hub proteins; however, none retained significance after FDR correction, whereas brush-border components (CDHR2, MUC3A, MUC13, ALPI) and actin cytoskeletal regulators remained the most statistically robust alterations. Integrated analysis further highlighted focal adhesion-related proteins with coordinated expression and phosphorylation changes. Conclusions: This exploratory study provides the first integrative proteomic and phosphoproteomic characterization of CEAS, suggesting that impairment of the intestinal brush border and mucosal barrier, together with actin cytoskeletal reorganization, may distinguish CEAS from immune-dominant CD. These findings are hypothesis-generating and require validation in larger cohorts. Full article

Metabolic dysfunction, a hallmark of diet-induced obesity (DIO), is increasingly attributed to alterations in intestinal nutrient and electrolyte transport. Yet the mechanisms that drive obesity-associated functional alterations of intestinal transporters remain incompletely understood. In this context, the effects of a high-fat diet (HFD) induced obesity on sodium-dependent glucose co-transporter 1 (SGLT1), Na⁺/H⁺ exchanger 3 (NHE3), and Cl⁻/HCO₃⁻ exchangers (DRA/PAT1), the primary glucose, sodium, and chloride absorptive pathways in mice small intestinal villus cells, were investigated. SGLT1 activity significantly increased in intact villus cells and brush border membrane vesicles (BBMV) from HFD-fed mice. Kinetic analysis demonstrated reduced Km without a change in Vmax, indicating enhanced transporter affinity. Notably, SGLT1 mRNA and protein expression, including BBM localization, were unchanged. Basolateral Na⁺/K⁺-ATPase activity was decreased, excluding enhanced Na⁺ gradient generation as the mechanism for SGLT1 stimulation. In contrast, DRA/PAT1 activity was significantly increased in HFD-fed mice, and kinetic studies revealed elevated Vmax without a change in Km, indicating increased transport capacity. DRA/PAT1 mRNA, total protein, and BBM expression were all significantly elevated. NHE3 activity and expression remained unchanged. These findings demonstrate that DIO enhances intestinal glucose absorption by increasing SGLT1 affinity and chloride absorption by upregulating DRA/PAT1 transcription. These transporter-specific alterations may amplify nutrient absorption and contribute to metabolic dysregulation in obesity. Full article

The importance of protein-based materials in agricultural pest control has received increasing attention in recent years. Herein, Plutella xylostella brush-border membrane vesicles (BBMVs) were used as a target to screen for human domain antibodies with insecticidal activity. Three rounds of panning of the phage display library yielded the domain antibody C4D, which competed with the Cry1Ac toxin to bind to P. xylostella BBMVs. Against P. xylostella larvae, the recombinant soluble C4D protein showed an LC₅₀ of 1.57 μg/cm² (95% fiducial limits: 0.83–2.54). Using pull-down assays and liquid chromatography–tandem mass spectrometry, we identified the C4D binding partner in P. xylostella midgut BBMVs to be a cadherin-like protein. Bio-Layer Interferometry assay revealed that the dissociation constant between soluble C4D and P. xylostella cadherin-like protein was 2.99 × 10⁻⁶ M. Thus, the present study explored strategies to generate insecticidal antibodies, and the human domain antibody C4D identified and characterized in this study can serve as a framework for generating novel insecticidal agents. Full article

Objective: To explore the preventive effect and mechanism of melatonin on high-fructose-induced renal injury in mice. Methods: A total of forty male C57BL/6J mice aged six weeks were randomly assigned to four groups: control group (CON), melatonin group (MLT), fructose group (FRU), and fructose + melatonin group (FRU + MLT). The concentration of the fructose solution was 30%, and the dose of melatonin was 10 mg/kg/day by intragastric administration. The experiment lasts for 10 weeks. Results: Liquid intake and energy intake were comparable between the FRU and FRU + MLT, both of which were significantly higher than that in the CON and MLT. MLT inhibited fructose-induced increased levels in serum creatinine (Cre), serum urea nitrogen (BUN), serum uric acid (UA), serum triglyceride (TG), renal kidney injury molecule-1 (KIM-1), and renal TG. Hematoxylin and Eosin (H&E) staining and Oil Red O (ORO) staining showed that MLT alleviated renal tubular dilatation, loss of brush border, epithelial cell detachment and lipid accumulation. Transmission electron microscope (TEM) observations showed that MLT increased autophagic vacuoles among mitochondria. Western blot analysis showed that, compared with the FRU, the FRU + MLT had elevated expression of AMP-activated protein kinase (AMPK) phosphorylation, along with a significant increase in the expression of its downstream mitophagy-related proteins (including PINK1, Parkin, LC3 II, and Beclin1), whereas the expression of p62 was markedly decreased. Furthermore, the expression levels of FAO-related proteins (including PPARα and CPT1A) in the FRU + MLT were significantly upregulated. Conclusions: MLT alleviates renal injury caused by high-fructose exposure in male mice and its mechanism might be associated with the regulation of mitophagy and fatty acid oxidation. Full article

Although the pancreas is the organ that produces the most critical digestive enzymes, there are other important contributors to the cleavage of food into absorbable units. Pre-pancreatic digestion of carbohydrates occurs through the action of salivary amylase. Pre-pancreatic digestion of fats is mediated by lingual and gastric lipases, and their action may be important as a signal for coordinated digestion. Pepsin, which is present in the stomach, initiates the digestion of dietary proteins into peptides and amplifies distal proteolysis. The major post-pancreatic intestinal carbohydrate-digesting enzymes are sucrase-isomaltase, maltase-glucoamylase and lactase-phlorizin hydrolase. There are no post-pancreatic mucosal enzymes that act on dietary triglycerides; however, the complete digestion of phospholipids depends on several brush border phospholipases. Intestinal processing is an important contributor to digestion of proteins, although mucosal proteases may serve as signaling proteins rather than as primary adjuncts to dietary protein digestion and absorption. This review describes the role of these non-pancreatic digestive enzymes in supporting nutritional health. Full article

Obesity is a complex chronic inflammatory condition that results from excess fat accumulation. It increases the risk of developing numerous co-morbidities such as Type 2 diabetes mellitus, cardiovascular disease, hypertension, and stroke. The adipose tissue is itself a vital endocrine organ that secretes numerous adipokines, cytokines, and exosomes, which are collectively known as the adipose-derived secretome (ADS). This ADS has been shown to influence and modulate many physiological processes. During obesity, the composition of ADS is altered, which may contribute to the development of obesity-associated diseases. Type-2 diabetes mellitus is one of the most common complications of obesity due to alterations in glucose homeostasis. Glucose absorption occurs via Na-glucose co-transport via SGLT1 at the brush border membrane (BBM) of small intestinal villus cells. This process of transepithelial glucose uptake is the primary method of glucose absorption from diet. However, how ADS mediates the function of SGLT1 is not yet known. This study aims to determine the mechanism of regulation of SGLT1 by ADS in intestinal epithelial cells. We show that ADS from OZR (but not LZR) stimulates SGLT1 in IEC-18 cells. OZR-ADS treatment diminished Na/K-ATPase activity in IEC-18 cells. Kinetic studies indicated that the mechanism of stimulation for SGLT1 during OZR-ADS treatment was secondary to an increase in the affinity (1/K_m) of the co-transporter for glucose without a change in co-transporter number. Western blot studies revealed that SGLT1 protein expression was unaltered in the two groups, confirming our kinetic studies. Immunoprecipitation demonstrated that an increase in the affinity of the SGLT1 protein was mediated by altered phosphorylation. In conclusion, during obesity, the adipose tissue secretome stimulates SGLT1 in intestinal epithelial cells, leading to an increase in affinity for glucose. The affinity change is due to alterations in SGLT1 phosphorylation. Together, these results may provide important insight into the mechanisms underlying altered glucose homeostasis in obesity and how this may lead to the development of Type 2 diabetes mellitus. Full article

The greater amberjack (Seriola dumerili), a key species in marine aquaculture, relies heavily on its intestine for nutrient absorption and immune function. However, the structural and functional specialization of its intestinal segments remains poorly understood. In this study, we divided the intestine of S. dumerili into foregut, midgut, and hindgut, and conducted a multi-omics analysis integrating histological staining (H&E/AB-PAS), digestive enzyme assays, transcriptome sequencing, and 16S rRNA microbiota profiling to characterize structural, functional, molecular, and microbial differences across intestinal segments. Histological examinations revealed that brush border microvillus length, muscle layer thickness, and folding height were significantly greater in the foregut and hindgut compared to the midgut, while mucus and goblet cell density was higher in the foregut and midgut. Digestive enzyme assays showed that lipase activity peaked in the foregut, α-amylase in the midgut, and protease in the midgut and hindgut. Alkaline phosphatase (AKP) and acid phosphatase (ACP) activities were highest in the foregut and midgut. Immune-related enzyme activities (SOD (Superoxide dismutase), GSH-Px (Glutathione peroxidase), T-AOC (Total Antioxidant Capacity)) were elevated and MDA levels were lower in the midgut, indicating its role as the primary immune site. Transcriptome analysis identified segment-specific expression of nutrient transporters, such as slc6a19b (hindgut, protein), apoa1b (foregut, lipid), and slc37a4 (midgut, carbohydrate). Microbiome analysis revealed Ruminococcus dominance in the foregut (lipid digestion) and Prevotella, Bifidobacterium, and Lactobacillus enrichment in the midgut (carbohydrate metabolism and immunity). These findings highlight functional zonation in S. dumerili: the foregut specializes in lipid digestion, the midgut in carbohydrate metabolism and immunity, and the hindgut in protein digestion. This study provides foundational insights for optimizing aquaculture practices and advancing research in nutrition, immunology, and disease modeling in S. dumerili. Full article

Aflatoxins (AFs) are secondary metabolites of Aspergillus spp. They are highly toxic, carcinogenic, and immunosuppressive; AFs cause nonspecific disorders in humans and animals, which makes their diagnosis complex. The objective was to describe the time course of toxic effects of a single exposure to AFs-contaminated feed. Fifteen male calves (2 weeks old) were examined over 30 days for clinical, biochemical, and pathological changes resulting from the ingestion of AF-contaminated feed (1.0 mg/kg BW). Compared with 15 unexposed calves, exposed calves showed transient depression and rough coat; BW gain, dry matter intake, albumin, total plasma protein, and hepatic and renal glutathione-S-transferase concentrations progressively decreased. However, conversion ratio (feed/BW), total bilirubin, direct bilirubin, alkaline phosphatase, reduced glutathione, gamma-glutamyltransferase, and alanine and aspartate aminotransferases progressively increased. Necropsy and histology at 7 days postexposure (dpe) showed liver with multifocal hemorrhages, yellowish coloration, friable consistency, periportal fibrosis, and steatosis. Kidneys were hemorrhagic, with brush border losses, glomerular atrophy, sclerotic glomerulonephritis, and lymphocytic infiltration. However, at 30 dpe, the liver showed pale discoloration, diffuse macrovesicular steatosis, and periportal fibrosis. The kidneys had mottled appearance and firm consistency, fibrosis, loss of normal architecture, and thickening of Bowman’s capsule. These results suggest that the identification of alterations in animal performance and biochemical and histological characteristics could be useful for integrating a proper diagnosis of bovine aflatoxicosis. Full article

Background/Objectives: Intestinal alkaline phosphatase (IAP) is an enzyme expressed in the intestinal brush border, which may exert anti-inflammatory effects by detoxifying lipopolysaccharides (LPSs), thereby preventing metabolic disorders. Various food components have been reported to influence IAP activity. However, few studies have evaluated the effects of fermented milk on IAP activity. In this study, we aimed to investigate fermented milk with high IAP-activating capacity and investigate its effect. Methods: We screened a skim milk culture (SC), a fermented milk model, using differentiated Caco-2 cells. We investigated the effect of SC on IAP activity and gene expression in the Drosophila midgut. Quantitative PCR and immunoblot assays were conducted to examine gene and protein levels. Results: Among the SC samples from different lactic acid bacteria or bifidobacteria, the SC of Lactobacillus johnsonii SBT0309 (LJ0309 SC) demonstrated a particularly strong capacity to activate IAP in Caco-2 cells, demonstrated by significantly increased IAP gene expression and protein levels in Caco-2 cells. Additionally, LJ0309 SC inhibited increased secretion of IL-8 in LPS-stimulated Caco-2 cells. Finally, in Drosophila melanogaster fed LJ0309 SC, we observed an increase in both IAP activity and gene expression in the midgut. Conclusions: LJ0309 SC increased IAP activity and gene expression in both Caco-2 cells and the Drosophila midgut, and inhibited the inflammatory response in LPS-stimulated Caco-2 cells. Although further in vivo studies are required, LJ0309 SC might help to ameliorate LPS-induced inflammation and disease via IAP activation. Full article

Malabsorption of NaCl is the primary cause of diarrhea in inflammatory bowel disease (IBD). Coupled NaCl absorption occurs via the dual operation of Na:H and Cl:HCO₃ exchange in the brush border membrane (BBM) of villus cells. Cl:HCO₃ exchange is mediated by BBM transporters DRA (downregulated in adenoma) and PAT1 (putative anion transporter 1) in the mammalian small intestine. DRA/PAT1-mediated Cl:HCO₃ exchange was significantly downregulated in the BBM of villus cells in a rabbit model of chronic ileitis, while Na:H exchange was unaffected. The inhibition of Cl:HCO₃ exchange was restored in the rabbits when treated with a broad-spectrum immunomodulator, i.e. a glucocorticoid, indicating that the downregulation of DRA/PAT1 is likely to be immune-mediated during chronic enteritis. Mucosal mast cells are one type of key immune cells that are known to proliferate and release immune inflammatory mediators, thus playing a significant role in the pathogenesis of IBD. However, how mast cells may regulate DRA- and PAT1-mediated Cl:HCO₃ exchange in a rabbit model of chronic ileitis is unknown. In this study, treatment of rabbits with chronic intestinal inflammation with the mast cell stabilizer ketotifen did not affect the mucosal architecture of the inflamed intestine. However, ketotifen treatment reversed the inhibition of Cl:HCO₃ activity in the BBM of villus cells. This restoration of Cl:HCO₃ activity to normal levels by ketotifen was found to be secondary to restoring the affinity of the exchangers for its substrate chloride. This observation was consistent with molecular studies, where the mRNA and BBM protein expressions of DRA and PAT1 remained unaffected in the villus cells under all experimental conditions. Thus, this study indicates that mast cells mediated the inhibition of coupled NaCl absorption by inhibiting Cl:HCO₃ exchange in a rabbit model of chronic enteritis. Full article

Insect control traits are a key component of improving the efficacy of insect pest management and maximizing crop yields for growers. Insect traits based on proteins expressed by the bacteria Bacillus thuringiensis (Bt) have proven to be very effective tools in achieving this goal. Unfortunately, the adaptability of insects has led to resistance to certain proteins in current commercial products. Therefore, new insecticidal traits representing a different mode of action (MoA) than those currently in use are needed. Cry1Ja has good insecticidal activity against various lepidopteran species, and it provides robust protection against insect feeding with in planta expression. For Bt proteins, different MoAs are determined by their binding sites in the insect midgut. In this study, competitive binding assays are performed using brush border membrane vesicles (BBMVs) from Helicoverpa zea, Spodoptera frugiperda, and Chrysodeixis includens to evaluate the MoA of Cry1Ja relative to representatives of the various Bt proteins that are expressed in current commercial products for lepidopteran insect protection. This study highlights differences in the shared Cry protein binding sites in three insect species, Cry1Ja bioactivity against Cry1Fa resistant FAW, and in planta efficacy against target pests. These data illustrate the potential of Cry1Ja for new insect trait development. Full article

Cassiae semen, commonly consumed as roasted tea, has been widely used for both medicinal purposes and dietary supplements. In this study, we investigated the nephrotoxic effects and underlying mechanisms of Cassiae semen aqueous extracts (CSAEs) using computational and animal models. Both male and female Sprague Dawley rats were treated with 4.73–47.30 g/kg (body weight) of CSAEs by oral gavage twice a day for 7–28 days. We found that serum and urinary biomarkers of kidney injury and kidney coefficients were increased in a dose-dependent manner, and were accompanied by morphological alterations in the kidneys of CSAEs-treated rats. Computational and molecular docking approaches predicted that the three most abundant components of CSAEs—obtusifolin, aurantio-obtusin, and obtusin—exhibited strong affinity for the binding of F-actin, ROCK1, and Rac1, and the RhoA–ROCK pathway was identified as the most likely regulatory mechanism mediating the nephrotoxicity of CSAEs. Consistently, immunofluorescence staining revealed F-actin and cytoskeleton were frequently disturbed in renal cells and brush borders at high doses of CSAEs. Results from gene expression analyses confirmed that CSAEs suppressed the key proteins in the RhoA–ROCK signaling pathway and consequently the expression of F-actin and its stabilization genes. In summary, our findings suggest that Cassiae semen can depolymerize and destabilize actin cytoskeleton by inhibition of the RhoA–ROCK pathway and/or direct binding to F-actin, leading to nephrotoxicity. The consumption of Cassiae semen as a supplement and medicine warrants attention. Full article

Organogenesis occurs in the uterus under low oxygen levels (4%). Preterm birth exposes immature newborns to a hyperoxic environment, which can induce a massive production of reactive oxygen species and potentially affect organ development, leading to diseases such as necrotizing enterocolitis. The β3-adrenoreceptor (β3-AR) has an oxygen-dependent regulatory mechanism, and its activation exerts an antioxidant effect. To test the hypothesis that β3-AR could protect postnatal ileal development from the negative impact of high oxygen levels, Sprague–Dawley rat pups were raised under normoxia (21%) or hyperoxia (85%) for the first 2 weeks after birth and treated or not with BRL37344, a selective β3-AR agonist, at 1, 3, or 6 mg/kg. Hyperoxia alters ileal mucosal morphology, leading to increased cell lipid oxidation byproducts, reduced presence of β3-AR-positive resident cells, decreased junctional protein expression, disrupted brush border, mucin over-production, and impaired vascularization. Treatment with 3 mg/kg of BRL37344 prevented these alterations, although not completely, while the lower 1 mg/kg dose was ineffective, and the higher 6 mg/kg dose was toxic. Our findings indicate the potential of β3-AR agonism as a new therapeutic approach to counteract the hyperoxia-induced ileal alterations and, more generally, the disorders of prematurity related to supra-physiologic oxygen exposure. Full article

Liraglutide, a glucagon-like peptide 1 analog used to treat type 2 diabetes and obesity, is a potential new treatment modality for bile acid (BA) diarrhea. Here, we show that administration of liraglutide significantly decreased total BAs, especially the primary BAs, including cholic acid, chenodeoxycholic acid, taurocholic acid, taurochenodeoxycholic acid, glycocholic acid, and β-muricholic acid, in the liver and feces. In addition, liraglutide significantly decreased tryptophan metabolites, including L-tryptophan, serotonin, 5-hydroxy indole-3-acetic acid, L-kynurenine, and xanthurenic acid, in the colon, whereas it significantly increased indole-3-propionic acid. Moreover, the administration of liraglutide remarkably decreased the expression of apical sodium-dependent bile acid transporter, which mediates BA uptake across the apical brush border member in the ileum, ileal BA binding protein, and fibroblast growth factor 15 in association with decreased expression of the BA-activated nuclear receptor farnesoid X receptor and the heteromeric organic solute transporter Ostα/β, which induces BA excretion, in the ileum. Liraglutide acutely decreased body weight and blood glucose levels in association with decreases in plasma insulin and serotonin levels in food-deprived mice. These findings suggest the potential of liraglutide as a novel inhibitor of primary BAs and serotonin in the colon. Full article

Iron deficiency remains a public health challenge globally. Prebiotics have the potential to improve iron bioavailability by modulating intestinal bacterial population, increasing SCFA production, and stimulating expression of brush border membrane (BBM) iron transport proteins among iron-deficient populations. This study intended to investigate the potential effects of soluble extracts from the cotyledon and seed coat of three pea (Pisum sativum) varieties (CDC Striker, CDC Dakota, and CDC Meadow) on the expression of BBM iron-related proteins (DCYTB and DMT1) and populations of beneficial intestinal bacteria in vivo using the Gallus gallus model by oral gavage (one day old chicks) with 1 mL of 50 mg/mL pea soluble extract solutions. The seed coat treatment groups increased the relative abundance of Bifidobacterium compared to the cotyledon treatment groups, with CDC Dakota seed coat (dark brown pigmented) recording the highest relative abundance of Bifidobacterium. In contrast, CDC Striker Cotyledon (dark-green-pigmented) significantly increased the relative abundance of Lactobacillus (p < 0.05). Subsequently, the two dark-pigmented treatment groups (CDC Striker Cotyledon and CDC Dakota seed coats) recorded the highest expression of DCYTB. Our study suggests that soluble extracts from the pea seed coat and dark-pigmented pea cotyledon may improve iron bioavailability by affecting intestinal bacterial populations. Full article