Intestinal Epithelial Cell Proliferation Research Articles

CPT1 Mediated Ionizing Radiation-Induced Intestinal Injury Proliferation via Shifting FAO Metabolism Pathway and Activating the ERK1/2 and JNK Pathway.

The intestinal compensatory proliferative potential is a key influencing factor for susceptibility to radiation-induced intestinal injury. Studies indicated that the carnitine palmitoyltransferase 1 (CPT1) mediated fatty acid β-oxidation (FAO) plays a crucial role in promoting the survival and proliferation of tumor cells. Here, we aimed to explore the effect of 60Co gamma rays on CPT1 mediated FAO in the radiation-induced intestinal injury models, and investigate the role of CPT1 mediated FAO in the survival and proliferation of intestinal cells after irradiation. We detected the changed of FAO in the plasma and small intestine of Sprague Dawley (SD) rats at 24 h after 60Co gamma irradiation (0, 5 and 10 Gy), using target metabolomics, qRT-PCR, immunohistochemistry (IHC), western blot (WB) and related enzymatic activity kits. We then analyzed the FAO changes in radiation-induced intestinal injury models regardless of ex vivo (mice enteroids), or in vitro (normal human intestinal epithelial cell lines, HIEC-6). HIEC-6 cells were transduced with lentivirus vector GV392 and treated with puromycin for obtaining CPT1 stable knockout cell lines, named CPT1 KO. CPT1 enzymatic activities of HIEC-6 cells and mice enteroids were also inhibited by pharmaceutical inhibitor ST1326 and Etomoxir (ETO), to study the function of CPT1 in the survival and proliferation of HIEC-6 cells after 60Co gamma irradiation. We found that CPT1 mediated FAO was altered in the small intestine of the SD rats after irradiation, especially, the expression level and enzymatic activity of CPT1 were significantly increased. Similarly, the expression levels of CPT1 were also remarkably enhanced in mice enteroids and HIEC-6 cells after irradiation. CPT1 inhibition decreased the proliferation of the HIEC-6 cells and mice enteroids after irradiation partially by reducing the extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways activation, CPT1 inhibition also reduced the proliferation of mice enteroids after irradiation partially by down-regulating the Wnt/β-catenin signaling activity. In conclusion, our study indicated that CPT1 plays a crucial role in promoting intestinal epithelial cell proliferation after irradiation.

CPT1 Mediated Ionizing Radiation-Induced Intestinal Injury Proliferation via Shifting FAO Metabolism Pathway and Activating the ERK1/2 and JNK Pathway.

The intestinal compensatory proliferative potential is a key influencing factor for susceptibility to radiation-induced intestinal injury. Studies indicated that the carnitine palmitoyltransferase 1 (CPT1) mediated fatty acid β-oxidation (FAO) plays a crucial role in promoting the survival and proliferation of tumor cells. Here, we aimed to explore the effect of 60Co gamma rays on CPT1 mediated FAO in the radiation-induced intestinal injury models, and investigate the role of CPT1 mediated FAO in the survival and proliferation of intestinal cells after irradiation. We detected the changed of FAO in the plasma and small intestine of Sprague Dawley (SD) rats at 24 h after 60Co gamma irradiation (0, 5 and 10 Gy), using target metabolomics, qRT-PCR, immunohistochemistry (IHC), western blot (WB) and related enzymatic activity kits. We then analyzed the FAO changes in radiation-induced intestinal injury models regardless of ex vivo (mice enteroids), or in vitro (normal human intestinal epithelial cell lines, HIEC-6). HIEC-6 cells were transduced with lentivirus vector GV392 and treated with puromycin for obtaining CPT1 stable knockout cell lines, named CPT1 KO. CPT1 enzymatic activities of HIEC-6 cells and mice enteroids were also inhibited by pharmaceutical inhibitor ST1326 and Etomoxir (ETO), to study the function of CPT1 in the survival and proliferation of HIEC-6 cells after 60Co gamma irradiation. We found that CPT1 mediated FAO was altered in the small intestine of the SD rats after irradiation, especially, the expression level and enzymatic activity of CPT1 were significantly increased. Similarly, the expression levels of CPT1 were also remarkably enhanced in mice enteroids and HIEC-6 cells after irradiation. CPT1 inhibition decreased the proliferation of the HIEC-6 cells and mice enteroids after irradiation partially by reducing the extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) pathways activation, CPT1 inhibition also reduced the proliferation of mice enteroids after irradiation partially by down-regulating the Wnt/β-catenin signaling activity. In conclusion, our study indicated that CPT1 plays a crucial role in promoting intestinal epithelial cell proliferation after irradiation.

Qingyi decoction attenuates intestinal epithelial cell injury via the calcineurin/nuclear factor of activated T-cells pathway.

BACKGROUNDRecent studies have demonstrated that dysfunction of the intestinal barrier is a significant contributing factor to the development of severe acute pancreatitis (SAP). A stable intestinal mucosa barrier functions as a major anatomic and functional barrier, owing to the balance between intestinal epithelial cell (IEC) proliferation and apoptosis. There is some evidence that calcium overload may trigger IEC apoptosis and that calcineurin (CaN)/nuclear factor of activated T-cells (NFAT) signaling might play an important role in calcium-mediated apoptosis.AIMTo investigate the potential mechanisms underlying the therapeutic effect of Qingyi decoction (QYD) in SAP.METHODSA rat model of SAP was created via retrograde infusion of sodium deoxycholate. Serum levels of amylase, tumor necrosis factor (TNF-α), interleukin (IL)-6, D-lactic acid, and diamine oxidase (DAO); histological changes; and apoptosis of IECs were examined in rats with or without QYD treatment. The expression of the two subunits of CaN and NFAT in intestinal tissue was measured via quantitative real-time polymerase chain reaction and western blotting. For in vitro studies, Caco-2 cells were treated with lipopolysaccharide (LPS) and QYD serum, and then cell viability and intracellular calcium levels were detected.RESULTSRetrograde infusion of sodium deoxycholate increased the severity of pancreatic and intestinal pathology and the levels of serum amylase, TNF-α, and IL-6. Both the indicators of intestinal mucosa damage (D-lactic acid and DAO) and the levels of IEC apoptosis were elevated in the SAP group. QYD treatment reduced the serum levels of amylase, TNF-α, IL-6, D-lactic acid, and DAO and attenuated the histological findings. IEC apoptosis associated with SAP was ameliorated under QYD treatment. In addition, the protein expression levels of the two subunits of CaN were remarkably elevated in the SAP group, and the NFATc3 gene was significantly upregulated at both the transcript and protein levels in the SAP group compared with the control group. QYD significantly restrained CaN and NFATc3 gene expression in the intestine, which was upregulated in the SAP group. Furthermore, QYD serum significantly decreased the LPS-induced elevation in intracellular free Ca2+ levels and inhibited cell death.CONCLUSIONQYD can exert protective effects against intestinal mucosa damage caused by SAP and the protective effects are mediated, at least partially, by restraining IEC apoptosis via the CaN/NFATc3 pathway.

IL-27 Promotes Intestinal Barrier Integrity following Ethanol Intoxication and Burn Injury.

Alcohol intoxication combined with burn injury can lead to life-threatening complications, including sepsis, multiple organ failure, and death. After an acute burn, the gastrointestinal system becomes hypoxic because of fluid loss and reduction of intestinal blood flow. This can cause perturbations in the intestinal epithelial barrier, immune function, and the composition of the gut microbiome. Increased gut permeability leads to proinflammatory signaling, contributing to further damage to the intestinal barrier. Recent studies have suggested that IL-27 plays an anti-inflammatory role, which may be beneficial in intestinal barrier repair. Therefore, in this study, we examined the effect of ethanol and burn injury on IL-27 in the small intestine, as well as the potential beneficial role of IL-27 in restoring the intestinal barrier after intoxication and burn. Male C57BL/6 mice were gavaged with 2.9 g/kg ethanol before receiving a ∼12.5% total body surface area scald burn with or without rIL-27 in resuscitation fluid. Our results demonstrate that IL-27-producing cells are reduced in the small intestine after injury. When IL-27 is supplemented in resuscitation fluid, we were able to restore intestinal barrier integrity and transit, mediated through increased intestinal epithelial cell proliferation, reduced inflammatory cytokines, and increased anti-inflammatory cytokine IL-10. We also observed increased gene expression of tight junction proteins. These findings suggest that IL-27 may be a contributor to maintaining proper intestinal barrier function after injury through multiple mechanisms, including preventing excess inflammation and promoting intestinal epithelial cell proliferation and tight junction integrity.

Preparation of healing promotive alanyl-glutamine-poly(p-dioxanone) electrospun membrane integrated with gentamycin and its application for intestinal anastomosis in rats.

Anastomosis surgery at the intestinal site is performed on millions of individuals every year. However, several persistent complications, such as anastomotic leakage, abnormal adhesion, and anastomotic stenosis, have been observed after the surgery. For promoting anastomotic healing and to overcome the challenges mentioned above, re-epithelialization at anastomotic sites is crucial. In this study, an epithelialization-promoting macromolecular prodrug Ala-Gln-PPDO was prepared and processed into fibrous membranes by electrospinning. Ala-Gln and gentamicin were sustainably released from the electrospun membranes with degradation of these membranes to promote the proliferation of rat intestinal epithelial cells and suppress the proliferation of Staphylococcus aureus and Escherichia coli. The comprehensive repair effects of Ala-Gln-PPDO membranes have been evaluated in rat models of intestinal anastomosis in this study. Application of Ala-Gln-PPDO membranes, especially the gentamicin-incorporated Ala-Gln-PPDO ones, could prevent adhesion between the injured intestine and surrounding intestinal tissues. In addition, they did not affect the healing strength of anastomotic stoma negatively and could promote re-epithelialization at the anastomotic sites. Furthermore, the gentamicin-incorporated Ala-Gln-PPDO membranes could relieve stenosis at anastomotic sites. The gentamicin-incorporated Ala-Gln-PPDO electrospun membrane is a promising, comprehensive implantable material for promoting healing after gastrointestinal anastomosis owing to its effects involving the promotion of re-epithelialization, prevention of adhesion, and relieving of anastomotic stenosis.

Lactobacillus derived from breast milk facilitates intestinal development in IUGR rats.

The intestinal microbiota contributes to infant's intestine homeostasis. This study aimed to analyse how probiotics derived from breast milk promote infant intestinal development in rat pups. The effect of potential probiotics derived from breast milk on development of intrauterine growth retardation (IUGR) newborn rats' intestine was investigated. Limosilactobacillus oris ML-329 and Lacticaseibacillus paracasei ML-446 exhibited good hydrophobicity percentages (p < 0.05). ML-446 showed a significant effect on intestinal length and weight (p < 0.05). Meanwhile, the villus height of the IUGR newborn rats fed with ML-329 was significantly higher compared with those fed with Lacticaseibacillus rhamnosus GG (p < 0.05). Moreover, ML-329 and ML-446 both significantly stimulated the proliferation and differentiation of intestinal epithelial cells by increasing the number of ki67-positive cells, goblet cells, and lysozyme-positive Paneth cells (p < 0.05) through Wnt and Notch pathway. The proliferation and differentiation stimulating effects of ML-329 and ML-446 on IECs in the jejunum, ileum, and colon were mediated by activating the Wnt pathway with increased expression of wnt, lrp5, and β-catenin genes and accumulation of β-catenin, and by downregulating the Notch signalling pathway with decreased expression of the activated notch protein. Lactobacillus could facilitate IUGR rat pups' intestinal development and enhance the proliferation of Paneth cells and goblet cells. These findings provide further insights into promotion of the intestinal development by breast milk-derived beneficial microbes in early life of the IUGR newborn rats.

Tumor cell-derived ANGPTL2 promotes β-catenin-driven intestinal tumorigenesis.

Uncontrolled proliferation of intestinal epithelial cells caused by mutations in genes of the WNT/β-catenin pathway is associated with development of intestinal cancers. We previously reported that intestinal stromal cell-derived angiopoietin-like protein 2 (ANGPTL2) controls epithelial regeneration and intestinal immune responses. However, the role of tumor cell-derived ANGPTL2 in intestinal tumorigenesis remained unclear. Here, we show that tumor cell-derived ANGPTL2 promotes β-catenin-driven intestinal tumorigenesis. ANGPTL2 deficiency suppressed intestinal tumor development in an experimental mouse model of sporadic colon cancer. We also found that increased ANGPTL2 expression in colorectal cancer (CRC) cells augments β-catenin pathway signaling and promotes tumor cell proliferation. Relevant to mechanism, our findings suggest that tumor cell-derived ANGPTL2 upregulates expression of OB-cadherin, which then interacts with β-catenin, blocking destruction complex-independent proteasomal degradation of β-catenin proteins. Moreover, our observations support a model whereby ANGPTL2-induced OB-cadherin expression in CRC cells is accompanied by decreased cell surface integrin α5β1 expression. These findings overall provide novel insight into mechanisms of β-catenin-driven intestinal tumorigenesis.

Effect of Fumonisin B1 on Proliferation and Apoptosis of Intestinal Porcine Epithelial Cells.

Fumonisin B1 (FB1), which is a mycotoxin produced by Fusarium moniliforme and Fusarium rotarum, has a number of toxic effects in animals. Moldy feed containing FB1 can damage the intestine. In this study, we used intestinal porcine epithelial cells (IPEC-J2) as an in vitro model to explore the effects of FB1 on cell cycle and apoptosis. The results showed that IPEC-J2 cells treated with 10, 20, and 40 μg/mL FB1 for 48 h experienced different degrees of damage manifested as decreases in cell number and viability, as well as cell shrinkage and floating. In addition, FB1 reduced cell proliferation and the mRNA and protein expression of proliferating cell nuclear antigen (PCNA), cyclin-dependent kinase 2 (CDK2), CDK4, cyclinD1, and cyclinE1. FB1 blocked the cell cycle in the G1 phase. FB1 also induced mitochondrial pathway apoptosis, reduced mitochondrial membrane potential, and promoted mRNA and protein expression of Caspase3, Caspase9, and Bax. The findings suggest that FB1 can induce IPEC-J2 cell damage, block the cell cycle, and promote cell apoptosis.

Functional, Diagnostic and Therapeutic Aspects of Bile.

Bile is a unique body fluid synthesized in our liver. Enterohepatic circulation preserves bile in our body through its efficient synthesis, transport, absorption, and reuptake. Bile is the main excretory route for bile salts, bilirubin, and potentially harmful exogenous lipophilic substances. The primary way of eliminating cholesterol is bile. Although bile has many organic and inorganic contents, bile acid is the most physiologically active component. Bile acids have a multitude of critical physiologic functions in our body. These include emulsification of dietary fat, absorption of fat and fat-soluble vitamins, maintaining glucose, lipid, and energy homeostasis, sustenance of intestinal epithelial integrity and epithelial cell proliferation, reducing inflammation in the intestine, and prevention of enteric infection due to its antimicrobial properties. But bile acids can be harmful in certain altered conditions like cholecystectomy, terminal ileal disease or resection, cholestasis, duodenogastric bile reflux, duodenogastroesophageal bile reflux, and bile acid diarrhea. Bile acids can have malignant potentials as well. There are also important diagnostic and therapeutic roles of bile acid and bile acid modulation.

Effects of Spermidine on Cell Proliferation, Migration, and Inflammatory Response in Porcine Enterocytes.

Polyamines have been demonstrated to be beneficial to porcine intestinal development. Our previous study showed that putrescine mitigates intestinal atrophy in weanling piglets and suppresses inflammatory response in porcine intestinal epithelial cells, it is still unknown the role of spermidine in mediating putrescine function. The current study aimed to investigate the effect of spermidine on the proliferation, migration, and inflammatory response in porcine intestinal epithelial cells (IPEC-J2 cell line). The effects of spermidine on proliferation and migration of IPEC-J2 cells were measured. Difluoromethyl ornithine (DFMO) and diethylglyoxal bis (guanylhydrazone) (DEGBG) were used to block the production of putrescine and spermidine, respectively. A cell inflammation model was established with lipopolysaccharides (LPS) stimulation. Gene expression and protein abundance were determined by real-time quantitative PCR and western blotting, respectively. Spermidine significantly enhanced cell proliferation in DFMO (or/and) DEGBG treated IPEC-J2 cells (p < 0.05). Pretreatment with putrescine restored cell growth inhibited by DFMO but did not prevent the decrease in cell proliferation caused by DEGBG (p > 0.05). Similarly, spermidine but not putrescine significantly elevated the rate of migration in DEGBG treated IPEC-J2 cells (p < 0.05). Spermidine deprivation by DEGBG dramatically enhanced mRNA abundance of pro-inflammatory cytokines IL-8, IL-6, and TNF-α (p < 0.05), and the addition of spermidine attenuated excessive expression of those inflammatory pro-inflammatory cytokines, moreover, spermidine but not putrescine suppressed the phosphorylation of NF-κB induced by DEGBG. Spermidine supplementation also significantly suppressed LPS-induced the expression of TNF-α. The present study highlights a novel insight that putrescine may be converted into spermidine to modulate cell proliferation, migration, and inflammatory response on porcine enterocytes.

Effects of Intestinal FXR-Related Molecules on Intestinal Mucosal Barriers in Biliary Tract Obstruction.

Background: The farnesoid X receptor (FXR) is a key factor regulating hepatic bile acid synthesis and enterohepatic circulation. Repression of bile acid synthesis by the FXR is a potential strategy for treating cholestatic liver disease. However, the role of intestinal FXR on the intestinal barrier and intestinal microbiota needs further investigation. Materials: Intestinal tissues were collected from patients with biliary atresia or without hepatobiliary disease. Then, intestinal mRNA levels of FXR-related molecules were determined. To investigate the effect of FXR activation, bile-duct-ligation rats were treated with obeticholic acid [OCA (5 mg/kg/day)] or vehicle (0.5% methyl cellulose) per oral gavage for 14 days. The mRNA levels of intestinal FXR, SHP, TNF-α, FGF15 and bile acid transporter levels were determined. In addition, the intestinal permeability, morphologic changes, and composition of the intestinal microbiota were evaluated. Gut Microbiome was determined by 16S rDNA MiSeq sequencing, and functional profiling of microbial communities was predicted with BugBase and PICRUSt2. Finally, the role of OCA in injured intestinal epithelial cell apoptosis and proliferation was examined by pretreatment with lipopolysaccharide (LPS) in Caco-2 cells. Results: The downstream of the FXR in ileum tissues was inhibited in biliary obstruction. Activation of the FXR signaling pathway by OCA significantly reduced liver fibrosis and intestinal inflammation, improved intestinal microbiota, and protected intestinal mucosa in BDL rats. OCA also altered the functional capacities of ileum microbiota in BDL rats. Significant differences existed between the controls and BDL rats, which were attenuated by OCA in the alpha diversity analysis. Principal coordinates analysis showed that microbial communities in BDL rats clustered separately from controls, and OCA treatment attenuated the distinction. Bugbase and PICRUSt2 analysis showed that OCA changed the composition and structure of the intestinal microbiota and improved the metabolic function of the intestinal microbiota by increasing the relative abundance of beneficial bacteria and reducing the relative abundance of harmful bacteria. Moreover, OCA reduced the apoptosis induced by LPS in Caco-2 cells. Conclusion: The FXR agonist, OCA, activates the intestinal FXR signaling pathway and improves the composition and structure of the intestinal microbiota and intestinal barrier in BDL rats.

The Function and the Affecting Factors of the Zebrafish Gut Microbiota.

Gut microbiota has become a topical issue in unraveling the research mechanisms underlying disease onset and progression. As an important and potential “organ,” gut microbiota plays an important role in regulating intestinal epithelial cell differentiation, proliferation, metabolic function and immune response, angiogenesis and host growth. More recently, zebrafish models have been used to study the interactions between gut microbiota and hosts. It has several advantages, such as short reproductive cycle, low rearing cost, transparent larvae, high genomic similarity to humans, and easy construction of germ-free (GF) and transgenic zebrafish. In our review, we reviewed a large amount of data focusing on the close relationship between gut microbiota and host health. Moreover, we outlined the functions of gut microbiota in regulating intestinal epithelial cell differentiation, intestinal epithelial cell proliferation, metabolic function, and immune response. More, we summarized major factors that can influence the composition, abundance, and diversity of gut microbiota, which will help us to understand the significance of gut microbiota in regulating host biological functions and provide options for maintaining the balance of host health.

Milk-Derived miR-22–3p Promotes Proliferation of Human Intestinal Epithelial Cells (HIECs) by Regulating Gene Expression

ObjectivesMicroRNAs (miRNAs) are small non-coding RNA involved in RNA silencing and post-transcriptional regulation of gene expression. Milk exosomes are microvesicles containing miRNAs, and miR-22–3p (miR-22) abundantly appears in human milk exosomes. Both human milk exosomes and miR-22 survive in vitro gastrointestinal digestion. The aim of the current study was to evaluate effects of milk derived miR-22 on intestinal epithelial cells in early life. MethodsTo evaluate effects of miR-22 on intestinal epithelial cells and mimic uptake of miR-22 in exosomes by intestinal epithelial cells, miR-22 was transfected to human intestinal epithelial cells (HIECs) using Lipofectamine, and then total RNA was isolated after 24 h for microarray assay. After microarray results were verified by qRT-PCR, microarray they were analyzed using the Bioconductor package limma and compared with miR-22 predicted target genes to identify a direct target gene for miR-22 in HIECs. ResultsTotally, 608 genes were markedly regulated by miR-22. Based on Gene Ontology terms, the roles of miR-22 in HIECs include promotion of proliferation and regulation of immune functions. A proliferation assay (BrdU) was subsequently conducted to confirm the effect of miR-22 on promotion of proliferation of HIECs. Based on analysis of the microarray results and miR-22 predicted target genes, C/EBPδ, a transcription factor, may be a direct target for miR-22. In miR-22 transfected HIECs, transcription and translation of the C/EBPδ gene was significantly inhibited, and cell proliferation was increased when the C/EBPδ gene was silenced by siRNA. A luciferase assay showed that miR-22 specifically bound to the 3’-untranslated region of the C/EBPδ gene. ConclusionsMilk-derived miR-22 promotes intestinal proliferation by modifying gene expression, and C/EBPδ may be an important direct target for miR-22 in human intestinal epithelial cells. Funding SourcesIntramural funds.

Factors Affecting Spontaneous Endocytosis and Survival of Probiotic Lactobacilli in Human Intestinal Epithelial Cells.

Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of commensal bacteria has not been studied in depth. Three in vitro methods, gentamicin protection, flow cytometry and confocal laser scanning microscopy, have been implemented to accurately assess the internalization of two lactobacillus strains—Lacticaseibacillus paracasei BL23 and Lacticaseibacillus rhamnosus GG—in Caco-2 and T84 intestinal epithelial cells (IECs) under a variety of physiological conditions and with specific inhibitors. First and most interesting, internalization occurred at a variable rate that depends on the bacterial strain and IEC line, and the most efficient was BL23 internalization by T84 and, second, efficient internalization required active IEC proliferation, as it improved naturally at the early confluence stages and by stimulation with epidermal growth factor (EGF). IFN-γ is bound to innate immune responses and autolysis; this cytokine had a significant effect on internalization, as shown by flow cytometry, but increased internalization was not perceived in all conditions, possibly because it was also stimulating autolysis and, as a consequence, the viability of bacteria after uptake could be affected. Bacterial uptake required actin polymerization, as shown by cytochalasin D inhibition, and it was partially bound to clathrin and caveolin dependent endocytosis. It also showed partial inhibition by ML7 indicating the involvement of cholesterol lipid rafts and myosin light chain kinase (MLCK) activation, at least in the LGG uptake by Caco-2. Most interestingly, bacteria remained viable inside the IEC for as long as 72 h without damaging the epithelial cells, and paracellular transcytosis was observed. These results stressed the fact that internalization of commensal and mutualistic bacteria is a natural, nonpathogenic process that may be relevant in crosstalk processes between the intestinal populations and the host, and future studies could determine its connection to processes such as commensal tolerance, resilience of microbial populations or transorganic bacterial migration.

JAC4 Protects from X-ray Radiation-Induced Intestinal Injury by JWA-Mediated Anti-Oxidation/Inflammation Signaling.

Radiation-induced intestinal injury is one of the major side effects in patients receiving radiation therapy. There is no specific treatment for radiation-induced enteritis in the clinic. We synthesized a compound, named JAC4, which is an agonist and can increase JWA protein expression. JWA has been shown to reduce oxidative stress, DNA damage, anti-apoptosis, and anti-inflammatory; in addition, the small intestine epithelium showed dysplasia in JWA knockout mice. We hypothesized that JAC4 might exert a protective effect against radiation-induced intestinal damage. Herein, X-ray radiation models were built both in mice and in intestinal crypt epithelial cells (IEC-6). C57BL/6J mice were treated with JAC4 by gavage before abdominal irradiation (ABI); the data showed that JAC4 significantly reduced radiation-induced intestinal mucosal damage and increased the survival rate. In addition, radiation-induced oxidative stress damage and systemic inflammatory response were also mitigated by JAC4 treatment. Moreover, JAC4 treatment alleviated DNA damage, decreased cell apoptosis, and maintained intestinal epithelial cell proliferation in mice. In vitro data showed that JAC4 treatment significantly inhibited ROS formation and cell apoptosis. Importantly, all the above protective effects of JAC4 on X-ray radiation-triggered intestinal injury were no longer determined in the intestinal epithelium of JWA knockout mice. Therefore, our results provide the first evidence that JAC4 protects the intestine from radiation-induced enteritis through JWA-mediated anti-oxidation/inflammation signaling.

Effects of supplemental myo-inositol on growth performance and apparent total tract digestibility of weanling piglets fed reduced protein high-phytate diets and intestinal epithelial cell proliferation and function.

Myo-inositol is a breakdown product of phytate produced in the gut through the action of phytase. Although the effect of phytase-released phosphorus (P) on growth performance of animals has been well characterized, there is still little understanding of the effect of myo-inositol. The first objective of this study was to determine the effects of added myo-inositol to a phytate-rich low-protein diet on growth performance and apparent total tract digestibility (ATTD) in growing piglets. The second objective was to determine whether myo-inositol could directly affect intestinal epithelial cell proliferation and function for which we used intestinal porcine epithelial cells (IPEC-J2). A total of 128 weanling piglets were allotted to four dietary treatments consisting of eight replicates per treatment and four piglets per replicate in a randomized complete block design for 4 wk. The four experimental diets comprised the positive control [PC; 20% crude protein (CP)], negative control (NC; 17% CP), negative control plus 2.0g/kg myo-inositol (NC+INO; 17% CP), and negative control plus 3000FTU/kg phytase (NC+PHY; 17% CP). Average daily feed intake (ADFI), average daily gain (ADG), and gain-feed ratio (G: F) were recorded. Phytase supplementation in the protein-deficient NC diet increased the G:F ratio (P < 0.05) without myo-inositol effects on growth performance. Phosphorus digestibility in the phytase-supplemented group increased compared to the PC, NC, and NC+INO groups, whereas plasma myo-inositol concentration was significantly higher (P < 0.05) in the NC+INO group. Due to the lack of myo-inositol effect on growth performance, an additional in vitro study was conducted to determine the direct effect of myo-inositol on the intestinal epithelium that might not be reflected in growth performance. Myo-inositol increased the mRNA abundance of selected nutrient transporters in a concentration-dependent manner (P < 0.05). Myo-inositol also enhanced barrier integrity in the IPEC-J2 monolayer by increasing the transepithelial electrical resistance (TEER) with reduced paracellular permeability of FITC-dextran (P < 0.05). In conclusion, despite the lack of myo-inositol effect on animal performance, the in vitro data indicate that myo-inositol may directly regulate gut barrier integrity. Addition of myo-inositol to pig diets at levels that enhance intestinal epithelial cell function may result in effects on growth performance and gut health of pigs.

Maternal Oxidized Soybean Oil Administration in Rats during Pregnancy and Lactation Alters the Intestinal DNA Methylation in Offspring.

As a food contaminant, oxidized oil or lipid oxidative products have been proven to exert toxicological effects on the growth and development of animals and humans. Research shows that maternal oxidative stress damage might transmit to another generation by epigenetic modulation. However, current evidence is still not clear on the mechanism of the effects of dietary oxidized oil during pregnancy on the two generations. This study employed a rat model fed with oxidized soybean oil (OSO) during pregnancy and lactation to explore the effects of the oxidative degree (0, 200, 400, and 800 mequiv of O2/kg) on the placental RNA methylation and DNA methylation in offspring jejunum. The results showed that following the ingestion of OSO, the placental genes of different m6A methylation were significantly enriched to nutrient metabolic processes and hormone activity. In addition, the intestine in offspring hypofunctioned observably, such as reducing the height of villi and the level of anti-inflammatory cytokine. Furthermore, maternal intake of OSO during pregnancy can damage the intestinal barrier function of offspring by inhibiting the proliferation and differentiation of intestinal epithelial cells and reducing the activity of intestinal DNA methyltransferase. In conclusion, this study reinforces the assertion that maternal OSO consumption during gestation and lactation negatively affects the placental health and intestinal development of suckling pups.

The function of Sphingosine-1-phosphate receptor 2 (S1PR2) in maintaining intestinal barrier and inducing ulcerative colitis

ABSTRACT Sphingosine-1-phosphate receptor 2 (S1PR2) was highly expressed in intestinal epithelial cells (IECs) and facilitated the proliferation of IECs. However, the specific function of S1PR2 in intestinal diseases, such as ulcerative colitis (UC), remains unclear. Accordingly, the current study set out to investigate the function of S1PR2 in maintaining intestinal barrier and inducing UC. S1PR2-overexpressed and knockdown Caco-2 cells were established to explore the function of S1PR2 on the permeability of IECs barrier. The UC-like mouse model in which UC is induced by dextran sulfate sodium (DSS) was established and utilized to investigate the role for S1PR2. The results showed that S1PR2 functioned as a maintainer of IECs permeability and a pathogenic factor for UC. A series of in vitro and in vivo experiments were conducted, and it was found that S1PR2 played an important role in intestinal epithelial cell proliferation and maintenance of intestinal epithelial cell barrier, possibly by the regulation on the expression level of SphK2, HDAC1, HDAC2, and ERK1/2 signaling pathway. The expression of S1PR2 was upregulated in UC mice and the colonic pathological damage in UC mice could be alleviated by the inhibition of S1PR2. Collectively, these results suggest that S1PR2 functions as a maintainer of IECs permeability and a pathogenic factor for UC. The research suggests S1PR2 may be an effective target for developing therapeutic strategies against UC. Abbreviations: S1PR2, Sphingosine-1-phosphate receptor 2; UC, ulcerative colitis; IECs, intestinal epithelial cells; DSS, dextran sulfate sodium; IBD, inflammation bowel disease; CD, Crohn’s disease; S1P, sphingosin-1-phosphate; SphK, sphingosine kinase; HIECs, human IECs; siRNA, small interfering RNA; CCK-8, cell counting kit-8; TEER, transepithelial electrical resistance; TEM, transmission electron microscope; RT-PCR, real-time reverse transcriptase polymerase-chain reaction; ELISA, enzyme-linked immunosorbent assay; HE, hematoxylin and eosin.

Dietary Tryptophan‐Lactobacillus rhamnosus GG Interactions Modify Intestinal Differentiation and Function

Although the influence of the gut microbiota on structure and proliferation of intestinal epithelial cells has been established, there is disconcordance on information related to cell type differentiation, because most studies on probiotics reflected an outcome from interactions among Lactobacillus, numerous existing microbes, and the host, with limited insight on the specific impact of Lactobacilli spp. For example, L. reuteri enhanced goblet and Paneth cell differentiation in intestine of conventionally‐raised chickens with an established commensal gut microbiota, confounding results. Here we fed gnotobiotic mice with tryptophan (t+) or trp‐free (t–) diets, followed by monocolonization with LGG (L+, ATCC 53103) or without (control, L–) for a total of 4 groups (L+t+, L+t–, L–t+, L–,t–), then ileum transcriptome was analyzed 3 wk later. L– mice remained germ‐free throughout while only LGG was associated with L+. Principal component analysis shows L+ or t+ by itself to modestly cluster away from L–t–, but the cluster depicting the combination of L+t+ was far removed from the others. The heatmap of whole ileum transcriptome shows several distinct groups of genes affected by t+ or by L+ alone. However, the simultaneous impact of L+t+ dramatically upregulates numerous gene clusters while downregulating a few. Volcano plots and Venn diagrams comparing L–t– with L–t+, or L+t– with L–t– indicate ~2300 unique genes affected by L+ (LGG) or t+ (tryptophan) alone. Comparisons between L+t+ and L+t– (effect of t with L) or between L+t+ and L–t+ (effect of L with t) each impact &gt;3800 genes, suggesting that synergistic interactions between L+ and t+ primarily underlie the probiotic impact ascribed to LGG and dietary t. Many of the genes upregulated by L+t+ have functions typical of mature enterocytes: tight junctions, brush border membrane transporters and enzymes, intestinal bile acid metabolism, lipid synthesis and fatty acid b‐oxidation. Many downregulated genes are antimicrobial and secreted peptides typical of differentiated Paneth and goblet cells. This latter result was recapitulated when reexamined in conventional mice perfused for 4 h with LGG, as expression of many defensins decreased by &gt;10‐fold, suggesting not only that this probiotic’s effects can arise from both acute ex vivo and chronic in vivo interactions with the host, but also in hosts housing a complex microbiota. Remarkably, Notch ligands Dll1 and Dll4 typically expressed in Paneth cells as well as Yap1, Axin2 and Ctnnb1 are upregulated in L+t+ ileum, suggesting downstream upregulation of Hes1 and repression of Atoh1, leading to suppression of the secretory lineage. In conclusion, LGG monocolonization may lead to synthesis of t+‐derived metabolites by both host and bacteria, leading to an enhancement of absorptive enterocyte functions and suppression of those by goblet and Paneth cells.

P‐cadherin regulates intestinal epithelial repair, but is dispensable for colitis associated colon cancer development

Recurrent chronic mucosal inflammation, which is characteristics for inflammatory bowel diseases (IBD), triggers significant changes in the intestinal epithelial homeostasis. These changes include leakiness of the gut barrier, formation of mucosal wounds and, in most severe cases, oncogenic transformation of colonic epithelium resulting in colitis‐associated colon cancer (CAC). Altered structure and dynamics of epithelial junctions is a hallmark of intestinal inflammation, mediating epithelial barrier injury and repair. P‐cadherin (gene name: CDH3) is an important component of adherens junctions (AJ), which is poorly expressed in normal intestinal epithelium, but could be induced in inflamed and injured mucosa. The goal of this his study was to investigate the roles of P‐cadherin in regulating intestinal inflammation, mucosal repair and CAC.P‐cadherin expression was markedly induced in the colonic epithelium of human IBD patients and CAC tissues. Roles of P‐cadherin in intestinal inflammation and tumorigenesis in vivo were investigated using a mouse strain with total P‐cadherin knockout. Dextran sulfate sodium (DSS)‐induced colitis was utilized to study mucosal inflammation, whereas CAC was established using a classical azoxymetane (AOM)/DSS model. Severity of acute DSS colitis was not affected by P‐cadherin knockout, however, P‐cadherin null mice exhibited faster recovery after DSS withdrawal indicating accelerated repair of injured mucosa. No significant differences in the number and size of colonic tumors was observed in P‐cadherin null and control mice after AOM/DSS induced CAC. Consistently, CRISPR/Cas9‐mediated knockout of P‐cadherin in SK‐CO15 and HCA7 human colonic epithelial cell lines accelerated epithelial wound healing without affecting cell proliferation. The faster migration of P‐cadherin depleted cells was associated with diminished cell‐matrix adhesions and increased cell spreading. Loss of P‐cadherin resulted in activation of Src kinase and the pro‐migratory phenotype of P‐cadherin depleted cell was reversed by pharmacological inhibition of Src. Furthermore, accelerated epithelial wound healing caused by loss of P‐cadherin was prevented by Rac1 inhibition. Our findings highlight P‐cadherin as a negative regulator of intestinal epithelial would heling in vitro and mucosal repair in vivo. By contrast, this AJ protein appears to be dispensable for intestinal epithelial cell proliferation and CAC development.