Intestinal Tissue Inflammation Research Articles

Abdominal wound length influences the postoperative serum level of interleukin-6 and recovery of flatus passage among patients with colorectal cancer.

A mini-laparotomy for colorectal cancer (CRC) has been reported to shorten postoperative ileus (POI) and hospital stay. Interleukin-6 (IL-6) plays a role in intestinal tissue inflammation, leading to POI. This study investigated the effects of abdominal wounds and IL-6 levels on POI in patients having CRC surgery. Forty-three patients with CRC underwent bowel resection. Serum samples were collected preoperatively and at 2, 24, and 48 h after surgery for cytokine quantification by ELISA. Clinical data, including time from surgery to first passage of flatus and postoperative hospital stay, demographic and pathological data, and routine blood tests, were compared statistically with abdominal wound length and the postoperative increments of cytokines (designated as Δ). The length of the abdominal wound showed a significant correlation with clinical variables (length of operation time, time of first flatus passage, and length of postoperative hospital stay) and cytokine variables (IL-6(Δ2 h), IL-8(Δ2 h) and IL-10(Δ2 h). Linear regression analysis showed that the abdominal wound length significantly influenced the operation time, time of first flatus passage, and length of postoperative hospital stay (p < 0.001). The length of the abdominal wound showed a significant influence on the IL-6(Δ2 h) and IL-8(Δ2 h) (p < 0.001, respectively) but no influence on IL-10(Δ2 h). IL-6(Δ2 h), but not IL-8(Δ2 h), significantly influenced the time to first flatus passage and length of hospital stay (p = 0.007, p = 0.006, respectively). The mini-laparotomy approach (wound length <7 cm) led to significantly shortened operation time, time of first flatus passage, length of postoperative stay (p = 0.004, p = 0.003, p = 0.006, respectively) as well as reduced postoperative increment of IL-6(Δ2 h) (p = 0.015). The mini-laparotomy for anterior resection surgery significantly influenced operation time, time of first passage of flatus, length of postoperative stay, and IL-6(Δ2 h). Our study is the first to report the complex interaction among the length of the abdominal wound, IL-6 serum level, recovery of the first passage of flatus, and postoperative hospital stay. These results suggest that smaller abdominal wounds and smaller postoperative IL-6 increments were associated with faster recovery of flatus passage and shorter hospital stays.

Glucose dependent resistance associated with intestinal microbiota facilitate teleost to survive bacterial infection

Host microbiota interaction affects the metabolism and immune regulation in the host. To explore the disease resistance mechanism and the host-microbiota interaction details, the intestinal transcriptome and microbiome of moribund and surviving fish infected with Aerompnas hydrophila as well as healthy controls were cross-analyzed. Survivors presented an intestinal microbiome with slight change and more intensive interspecies cooperation, while a distinct gene expression profile related to glycometabolism and immunomodulation was observed, resulting in lower-level inflammation in intestinal tissue. Genes related to FoxO, Insulin, and Glucagon signaling pathways, such as g6pc, socs2, and foxg1, correlated positively with intestinal Eubacterium_coprostanoligenes_Group, Mannheimia, Leptotrichia, and Shewanella, corresponding to a higher serum glucose level and IgM titer in surviving fish. Besides, Pseudomonas and Shewanella, with higher abundance in surviving fish, showed antagonism towards the pathogen in vitro, and a positive correlation with serum glucose level and IgM titer, respectively. Co-cultures promoted these antagonism effects and these effects connected with glucose concentration. Glucose supplementation to fish raised the survival rate significantly. In general, glycometabolism homeostasis is critical for fish to survive A. hydrophila infection. Metabolism modulation would be a potential approach to facilitate bacterial infection resistance.

WNT2B activates macrophages via NF-κB signaling pathway in inflammatory bowel disease.

Inflammation is a significant pathological manifestation of inflammatory bowel disease (IBD), yet its mechanism has remained unclear. Although WNT2B is enriched in the intestinal inflammatory tissue of IBD patients, the specific mechanism of WNT2B in the formation of intestinal inflammation remains unclear. This study was aimed to investigate whether macrophages expressing WNT2B can aggravate intestinal tissue inflammation. Samples were collected from both normal individuals and patients with IBD at multiple colon sites. Macrophages were identified using tissue immunofluorescence. IκB kinase (IKK)-interacting protein (IKIP), which interacts with WNT2B, was found by protein cross-linking and protein mass spectrometry. The expression of WNT2B, IKIP, the NF-κB pathway, and downstream molecules were analyzed. An acute colitis model of C57BL/6J mice was established using an adeno-associated virus (AAV)-mediated WNT2B knockdown system and 3% dextran sulfate sodium (DSS). The degree of intestinal inflammation in mice was assessed upon WNT2B knockdown in macrophages. Macrophages expressing WNT2B were found to be enriched in the colitis tissues of IBD patients. WNT2B in macrophages activated the NF-κB pathway and enhanced the expression of downstream inflammatory cytokines. By competitively binding IKIP, WNT2B reduced the binding of IKIP to IKKβ and promoted the activation of the NF-κB pathway. Using an AAV-mediated WNT2B knockdown system, WNT2B expression in intestinal macrophages was suppressed, leading to a reduction in intestinal inflammation. WNT2B activated the NF-κB pathway and enhanced the expression of downstream inflammatory cytokines by competitively binding to IKIP, potentially contributing to colon inflammatory injury in IBD.

Induced acute hyperglycemia modifies the barrier function of the intestinal epithelium by tissue inflammation and tight junction disruption resulting in hydroelectrolytic secretion in an animal model.

Diabetic-metabolic syndrome (MetS-D) has a high prevalence worldwide, in which an association with the rupture of the intestinal epithelium barrier function (IEBF) has been pointed out, but the functional and morphological properties are still not well understood. This study aimed to evaluate the impact of acute hyperglycemia diabetes on intestinal tight junction proteins, metabolic failure, intestinal ion and water transports, and IEBF parameters. Diabetes was induced in male Rattus norvegicus (200-310 g) with 0.5 mL of streptozotocin (70 mg/kg). Glycemic and clinical parameters were evaluated every 7 days, and intestinal parameters were evaluated on the 14th day. The MetS-D animals showed a clinical pattern of hyperglycemia, with increases in the area of villi and crypts, lactulose:mannitol ratio, myeloperoxidase (MPO) activity, and intestinal tissue concentrations of malondialdehyde (MDA), but showed a reduction in reduced glutathione (GSH) when these parameters were compared to the control. The MetS-D group had increased secretion of Na+, K+, Cl-, and water compared to the control group in ileal tissue. Furthermore, we observed a reduction in mRNA transcript of claudin-2, claudin-15, and NHE3 and increases of SGLT-1 and ZO-1 in the MetS-D group. These results showed that MetS-D triggered intestinal tissue inflammation, oxidative stress, complex alterations in gene regulatory protein transcriptions of intestinal transporters and tight junctions, damaging the IEBF and causing hydroelectrolyte secretion.

CX3CL1 promotes M1 macrophage polarization and osteoclast differentiation through NF-κB signaling pathway in ankylosing spondylitis in vitro.

Ankylosing spondylitis (AS) is an autoimmune disease with a genetic correlation and is characterized by inflammation in the axial skeleton and sacroiliac joints. Many AS patients also have inflammatory bowel diseases (IBD), but the underlying causes of intestinal inflammation and osteoporosis in AS are not well understood. CX3CL1, a protein involved in inflammation, has been found to be up-regulated in AS patients and AS-model mice. The authors investigated the effects of CX3CL1 on AS by studying its impact on macrophage polarization, inflammation factors, and osteoclast differentiation. Furthermore, the effects of inhibiting the NF-κB pathway and blocking CX3CL1 were assessed using BAY-117082 and anti-CX3CL1 mAb, respectively. AS model mice were used to evaluate the effects of anti-CX3CL1 mAb on limb thickness, spine rupture, and intestinal tissue damage. The authors found that CX3CL1 increased the expression of M1-type macrophage markers and inflammation factors, and promoted osteoclast differentiation. This effect was mediated through the NF-κB signaling pathway. Inhibition of the NF-κB pathway prevented M1-type macrophage polarization, reduced inflammation levels, and inhibited osteoclast differentiation. Injection of anti-CX3CL1 mAb alleviated limb thickness, spine rupture, and intestinal tissue damage in AS model mice by inhibiting M1-type macrophage polarization and reducing intestinal tissue inflammation. The study demonstrated that up-regulated CX3CL1 promotes M1-type macrophage polarization and osteoclast differentiation through the NF-κB signaling pathway. Inhibition of this pathway and blocking CX3CL1 can alleviate inflammation and bone destruction in AS. These findings contribute to a better understanding of the pathogenesis of AS and provide a basis for clinical diagnosis and treatment.

Gut Microbiome-Brain Axis as an Explanation for the Risk of Poor Neurodevelopment Outcome in Preterm Infants with Necrotizing Enterocolitis.

Necrotizing Enterocolitis (NEC) is characterized by an inflammation of intestinal tissue that primarily affects premature infants. It is the most common and devastating gastrointestinal morbidity of prematurity, but beyond intestinal morbidity, this condition has also been associated with an increased risk of neurodevelopmental delays that persist beyond infancy. Prematurity, enteral feeding, bacterial colonization, and prolonged exposure to antibiotics are all risk factors that predispose preterm infants to NEC. Interestingly, these factors are all also associated with the gut microbiome. However, whether or not there is a connection between the microbiome and the risk of neurodevelopmental delays in infants after NEC is still an emerging area of research. Furthermore, how microbes in the gut could impact a distant organ such as the brain is also poorly understood. In this review, we discuss the current understanding of NEC and the role of the gut microbiome-brain axis in neurodevelopmental outcomes after NEC. Understanding the potential role of the microbiome in neurodevelopmental outcomes is important as the microbiome is modifiable and thus offers the hope of improved therapeutic options. We highlight the progress and limitations in this field. Insights into the gut microbiome-brain axis may offer potential therapeutic approaches to improve the long-term outcomes of premature infants.

Effects of microencapsulated blend of organic acids and botanicals on growth performance, intestinal barrier function, inflammatory cytokines, and endocannabinoid system gene expression in broiler chickens

With restricted usage of growth-promoting antibiotics, identifying alternative feed additives that both improve intestinal barrier function and reduce inflammation is the center to improve chickens' health. This study examined the effects of a microencapsulated feed additive containing citric acid, sorbic acids, thymol, and vanillin on intestinal barrier function and inflammation status. A total of 240 birds were assigned to either a commercial control diet or control diet supplemented with 500 g/MT of the microencapsulated additive product. Birds were raised by feeding a 2-phase diet (starter, d 1 to d 21; and grower, d 15 to d 42). Growth performance was recorded weekly. At d 21 and d 42, total gastrointestinal tract permeability was evaluated by FITC-dextran (FD4) oral gavage. Jejunum-specific barrier functions were evaluated by Ussing chamber. Intestinal gene expression of selected epithelial cell markers, tight junction (TJ) proteins, inflammatory cytokines, and endocannabinoid system (ECS) markers were determined by RT-PCR. Statistical analysis was performed using Student t test. Results showed significant improvement of feed efficiency in the birds supplemented with the blend of organic acids and botanicals. At d 21, both oral and jejunal FD4 permeability were lower in the supplemented group. Jejunal transepithelial resistance was higher in the supplemented birds. At d 21, expression of TJs mRNA (CLDN1 and ZO2) was both upregulated in the jejunum and ileum of supplemented birds, while CLDN2 was downregulated in cecum. Proliferating cell marker SOX9 was higher expressed in jejunum and ceca. Goblet cell marker (MUC2) was upregulated, while Paneth cell marker (LYZ) was downregulated in the ileum. Proinflammatory cytokine expressions of IL1B, TNFA, and IFNG were downregulated in jejunum, while anti-inflammatory IL10 expression was higher in jejunum, ileum, cecum, and cecal tonsil. The ECS markers expressions were upregulated in most intestinal regions. Together, these results demonstrated that the blend of organic acids and botanical supplementation reduced inflammation, improved the TJs expression and intestinal barrier function, and thus improved chicken feed efficiency. The activated ECS may play a role in reducing intestinal tissue inflammation.

Morphine mediated neutrophil infiltration in intestinal tissue play essential role in histological damage and microbial dysbiosis

ABSTRACT The gut microbial ecosystem exhibits a complex bidirectional communication with the host and is one of the key contributing factors in determining mucosal immune homeostasis or an inflammatory state. Opioid use has been established to induce gut microbial dysbiosis consistent with increased intestinal tissue inflammation. In this study, we investigated the role of infiltrated immune cells in morphine-induced intestinal tissue damage and gut microbial dysbiosis in mice. Results reveal a significant increase in chemokine expression in intestinal tissues followed by increased neutrophil infiltration post morphine treatment which is direct consequence of a dysbiotic microbiome since the effect is attenuated in antibiotics treated animals and in germ-free mice. Neutrophil neutralization using anti-Ly6G monoclonal antibody showed a significant decrease in tissue damage and an increase in tight junction protein organization. 16S rRNA sequencing on intestinal samples highlighted the role of infiltrated neutrophils in modulating microbial community structure by providing a growth benefit for pathogenic bacteria, such as Enterococcus, and simultaneously causing a significant depletion of commensal bacteria, such as Lactobacillus. Taken together, we provide the first direct evidence that neutrophil infiltration contributes to morphine-induced intestinal tissue damage and gut microbial dysbiosis. Our findings implicate that inhibition of neutrophil infiltration may provide therapeutic benefits against gastrointestinal dysfunctions associated with opioid use.

Effects of sulfated polysaccharides from Laminaria japonica on regularating the gut microbiotan and alleviating intestinal inflammation in obese mice.

Due to their known health-enhancing properties, Laminaria japonica polysaccharides (LJP) may alleviate obesity via unknown mechanisms. This study aimed to investigate beneficial LJP effects and mechanism(s) of action using an animal obesity model (ICR mice fed a high-fat diet). First, LJP were confirmed to consist of sulfated polysaccharides via infrared spectroscopy. Next, LJP administration to mice was found to induce weight loss, reduce liver fat accumulation, and support healthy obesity-related blood serum indicator levels. Notably, LJP treatment significantly reduced TC and LDL levels and significantly increased HDL, LPL, UCP-2, and PPAR-α levels. Furthermore, examinations of tissues of LJP-treated mice revealed significantly reduced intestinal tissue inflammation as compared to corresponding results obtained for untreated obese controls. Additionally, LJP treatment relieved colonic shortening and reduced colonic levels of inflammatory factors TNF-α and IL-6. Further exploration of LJP treatment effects on mouse gut microbiota conducted via fecal 16S rRNA gene sequence-based gut microbiome profiling analysis revealed that LJP treatment increased the Bacteroidetes/Firmicutes ratio and increased gut abundances of probiotics Bacteroides acidifaciens, s_Lactobacillus intestinalis, and s_Lactobacillus murinus. In conclusion, these results collectively suggest that LJP use as a food supplement may alleviate obesity and related gut microbiota dysbiosis and intestinal inflammatory disorders.

Beneficial Effect of Gastrodia elata Blume and Poria cocos Wolf Administration on Acute UVB Irradiation by Alleviating Inflammation through Promoting the Gut-Skin Axis.

Bioactive compounds in some herbs can, directly and indirectly, protect against photoaging. We evaluated the effects of Gastrodia elata Blume (GE) and Poria cocos Wolf (PC) water extracts on ultraviolet (UV) B-induced skin lesions by acute UVB exposure in ICR mice and explored their mechanism of action. After removing the hair on the back of the mice, UVB (280–310 nm) was exposed to the back for 30 min to induce skin damage. Four UVB exposure groups were divided into the following according to the local application (1,3-butanediol extract) on the dorsal skin and oral intake (0.3 g water extract/kg body weight/day): 1,3-butanediol and cellulose(control; UV-Con), retinoic acid (positive-control; UV-Positive), PC extracts (UV-PC), and GE extracts (UV-GE). The fifth group had no UVB exposure with the same treatment as the UV-Con (Normal-control). The erythema, burns, erosion, and wounds of the UV-PC and UV-PC groups were alleviated, and the most significant improvements occurred in the UV-PC group. PC and GE reduced the thickness of the dorsal skin tissue, the penetration of mast cells, and malondialdehyde contents. The mRNA expression of TNF-α, IL-13, and IL-4, inflammatory factors, were also reduced significantly in the dorsal skin of the UV-PC and UV-GE groups. UV-PC, UV-GE, and UV-Positive showed improvements in UV-induced intestinal tissue inflammation. UV-Con deteriorated the intestinal morphology, and PC and GE alleviated it. The α-diversity of the fecal microbiota decreased in the UV-control, and UV-PC and UV-GE prevented the decrease. Fecal metagenome analysis revealed increased propionate biosynthesis in the UV-PC group but decreased lipopolysaccharide biosynthesis in the UV-PC and UV-GE groups compared to UV-Con. In conclusion, the local application and intake of PC and GE had significant therapeutic effects on acute UV-induced skin damage by reducing oxidative stress and proinflammatory cytokines, potentially promoting the gut-microbiota-gut-skin axis.

Distinctive location of piscine intestinal coccidiosis in Asian seabass fingerlings.

Coccidian infection (coccidiosis) is one of the most important causes of illness and death in the fish population, including Asian sea bass. The fingerling developmental stage is sensitive to various infectious agents. Economic losses are sustained by the sea bass aquaculture industry due to coccidiosis annually. However, the related pathological changes in the Asian sea bass fingerlings' three-part intestine remain unknown. This study aimed to investigate the Asian sea bass fingerlings' infection rate, infection location and site, and specific pathological lesions in the small intestinal tissues in a marine cage farming operation. A cross-sectional study was conducted on 44 fingerling fishes. Major coccidia proportions were identified morphologically at both the macroscopic and microscopic levels. The infection number was determined based on coccidia presence at various intestinal locations and sites. All areas were assessed for pathological lesions using semi-quantitative grading. Analysis of variance was used to perform all data analyses using the SPSS software. Data were expressed as means ± standard deviation. p < 0.05 was considered statistically significant. All Asian sea bass fingerlings studied were infected with coccidia. Enteritis and mucosal necrosis were distinct lesions found in the anterior intestine, which had the highest infection rate (49.94%), followed by the mid intestine (35.63%), and the posterior intestine (22.43%). The most common coccidian infection site was extracellular (subepithelial), followed by intracytoplasmic, and epicellular sites. Histopathological lesion determination revealed that intestinal tissue inflammation and epithelial injuries were predominantly seen in the anterior gut (p < 0.05). There was a high coccidian infection rate in Asian sea bass fingerlings from marine cage farming operations. Infection and intestinal damage at the anterior intestine, a major site, led to fingerling death. Disease prevention in the nursery should be intensive from the fingerling period to decrease the fatality rate caused by coccidia.

Dietary 25-Hydroxyvitamin D3 Supplementation Modulates Intestinal Cytokines in Young Broiler Chickens.

Vitamin D signaling is important for intestinal homeostasis. An increase in vitamin D receptors in immune cells can modulate cell phenotype and cytokine secretion. Cytokines regulate both pro- (interleukin 17; IL-17) and anti-inflammatory (IL-10) responses triggered by external stimuli. Inflammation in intestinal tissues can disrupt the structure and the remodeling of epithelial tight junction complexes, thus, compromising the protective barrier. The objective of the study was to determine the impact of dietary supplementation with 25-hydroxycholecalciferol (25OHD3), a hydroxylated metabolite of vitamin D, on intestinal cytokine abundance and epithelial barrier integrity over time in broilers. A randomized complete block design experiment was conducted to evaluate the effect of dietary 25OHD3 inclusion on relative protein expression of the cytokines, IL-17 and IL-10, and tight junction proteins, Zona Occludens 1 (ZO-1), and Claudin-1 (CLD-1), in broiler chicken duodenum and ileum from 3 to 21 days post-hatch. On day 0, male chicks (n = 168) were randomly assigned to raised floor pens. Experimental corn–soybean meal-based treatments were as follows: (1) a common starter diet containing 5,000 IU of D3 per kg of feed (VITD3) and (2) a common starter diet containing 2,240 IU of D3 + 2,760 IU of 25OHD3 per kg of feed (25OHD3) fed from days 0 to 21. On days 3, 6, 9, 12, 15, 18, and 21, 12 birds per treatment were euthanized to collect tissue samples for quantitative, multiplex, and fluorescent Western blot analysis. Target proteins were quantified using Image Quant TL 8.1 and expressed relative to total protein. Feeding 25OHD3 post-hatch decreased ileal IL-10 (anti-inflammatory) protein expression in 21-day-old broilers compared with VITD3 only (P = 0.0190). Broilers fed only VITD3 post-hatch had greater IL-17 (pro-inflammatory) protein expression in the ileum at 18 and 21 days-of-age (P = 0.0412) than those that fed 25OHD3. Dietary inclusion of 25OHD3 lowered the abundance of key inflammatory cytokines in the ileum of young broilers.

Intestinal Epithelial Barrier Function and Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants. NEC is characterized by intestinal tissue inflammation and necrosis. The intestinal barrier is altered in NEC, which potentially contributes to its pathogenesis by promoting intestinal bacterial translocation and stimulating the inflammatory response. In premature infants, many components of the intestinal barrier are immature. This article reviews the different components of the intestinal barrier and how their immaturity contributes to intestinal barrier dysfunction and NEC.

Carbon monoxide-releasing molecule-2 protects intestinal mucosal barrier function by reducing epithelial tight-junction damage in rats undergoing cardiopulmonary resuscitation

BackgroundIschemia-reperfusion injury (IRI) to the small intestine is associated with the development of systemic inflammation and multiple organ failure after cardiopulmonary resuscitation (CPR). It has been reported that exogenous carbon monoxide (CO) reduces IRI. This study aimed to assess the effects of carbon monoxide-releasing molecule-2 (CORM-2) on intestinal mucosal barrier function in rats undergoing CPR. MethodsWe established a rat model of asphyxiation-induced cardiac arrest (CA) and resuscitation to study intestinal IRI, and measured the serum levels of intestinal fatty acid-binding protein. Morphological changes were investigated using light and electron microscopes. The expression levels of claudin 3 (CLDN3), occludin (OCLN), zonula occludens 1 (ZO-1), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and nuclear factor kappa B (NF-κB) p65 were detected by western blotting. ResultsCompared with the sham-operated group, histological changes and transmission electron microscopy revealed severe intestinal mucosal injury in the CPR and inactive CORM-2 (iCORM-2) groups. In contrast, CORM-2 alleviated intestinal IRI. CORM-2, unlike iCORM-2, markedly decreased the Chiu's scores (2.38 ± 0.38 vs. 4.59 ± 0.34; P < 0.05) and serum intestinal fatty acid-binding protein level (306.10 ± 19.22 vs. 585.64 ± 119.84 pg/mL; P < 0.05) compared with the CPR group. In addition, CORM-2 upregulated the expression levels of tight junction proteins (CLDN3, OCLN, and ZO-1) (P < 0.05) and downregulated those of IL-10, TNF-α, and NF-кB p65 (P < 0.05) in the ileum tissue of rats that received CPR. ConclusionsCORM-2 prevented intestinal mucosal damage as a result of IRI during CPR. The underlying protective mechanism was associated with inhibition of ischemia-reperfusion-induced changes in intestinal epithelial permeability and inflammation in intestinal tissue.

Arginase impedes the resolution of colitis by altering the microbiome and metabolome.

Arginase 1 (Arg1), which converts l-arginine into ornithine and urea, exerts pleiotropic immunoregulatory effects. However, the function of Arg1 in inflammatory bowel disease (IBD) remains poorly characterized. Here, we found that Arg1 expression correlated with the degree of inflammation in intestinal tissues from IBD patients. In mice, Arg1 was upregulated in an IL-4/IL-13- and intestinal microbiota-dependent manner. Tie2-Cre Arg1fl/fl mice lacking Arg1 in hematopoietic and endothelial cells recovered faster from colitis than Arg1-expressing (Arg1fl/fl) littermates. This correlated with decreased vessel density, compositional changes in intestinal microbiota, diminished infiltration by myeloid cells, and an accumulation of intraluminal polyamines that promote epithelial healing. The proresolving effect of Arg1 deletion was reduced by an l-arginine-free diet, but rescued by simultaneous deletion of other l-arginine-metabolizing enzymes, such as Arg2 or Nos2, demonstrating that protection from colitis requires l-arginine. Fecal microbiota transfers from Tie2-Cre Arg1fl/fl mice into WT recipients ameliorated intestinal inflammation, while transfers from WT littermates into Arg1-deficient mice prevented an advanced recovery from colitis. Thus, an increased availability of l-arginine as well as altered intestinal microbiota and metabolic products accounts for the accelerated resolution from colitis in the absence of Arg1. Consequently, l-arginine metabolism may serve as a target for clinical intervention in IBD patients.

Intestinal Stem Cell Niche Defects Result in Impaired 3D Organoid Formation in Mouse Models of Crohn's Disease-like Ileitis.

SummaryIntestinal epithelial barrier dysfunction is a risk factor in the pathogenesis of Crohn’s disease (CD); however, no corrective FDA-approved therapies exist. We used an enteroid (EnO)-based system in two murine models of experimental CD, SAMP1/YitFc (SAMP) and TNFΔARE/+ (TNF). While severely inflamed SAMP mice do not generate EnOs, “inflammation-free” SAMP mice form EnO structures with impaired morphology and reduced intestinal stem cell (ISC) and Paneth cell viability. We validated these findings in TNF mice concluding that inflammation in intestinal tissues impedes EnO generation and suppressing inflammation by steroid administration partially rescues impaired formation in SAMP mice. We generated the first high-resolution transcriptional profile of the SAMP ISC niche demonstrating that alterations in multiple key pathways contribute to niche defect and targeting them may partially rescue the phenotype. Furthermore, we correlated the defects in formation and the rescue of EnO formation to reduced viability of ISCs and Paneth cells.

Wheat Consumption Aggravates Colitis in Mice via Amylase Trypsin Inhibitor–mediated Dysbiosis

Wheat has become the world's major staple and its consumption correlates with prevalence of noncommunicable disorders such as inflammatory bowel diseases. Amylase trypsin inhibitors (ATIs), a component of wheat, activate the intestine's innate immune response via toll-like receptor 4 (TLR4). We investigated the effects of wheat and ATIs on severity of colitis and fecal microbiota in mice. C57BL/6 wild-type and Tlr4-/- mice were fed wheat- or ATI-containing diets or a wheat-free (control) diet and then given dextran sodium sulfate to induce colitis; we also studied Il10-/- mice, which develop spontaneous colitis. Changes in fecal bacteria were assessed by taxa-specific quantitative polymerase chain reaction and 16S ribosomal RNA metagenomic sequencing. Feces were collected from mice on wheat-containing, ATI-containing, control diets and transplanted to intestines of mice with and without colitis on control or on ATI-containing diets. Intestinal tissues were collected and analyzed by histology, immunohistochemistry, and flow cytometry. Bacteria with reported immunomodulatory effects were incubated with ATIs and analyzed in radial diffusion assays. The wheat- or ATI-containing diets equally increased inflammation in intestinal tissues of C57BL/6 mice with colitis, compared with mice on control diets. The ATI-containing diet promoted expansion of taxa associated with development of colitis comparable to the wheat-containing diet. ATIs inhibited proliferation of specific human commensal bacteria in radial diffusion assays. Transplantation of microbiota from feces of mice fed the wheat- or ATI-containing diets to intestines of mice on control diets increased the severity of colitis in these mice. The ATI-containing diet did not increase the severity of colitis in Tlr4-/- mice. Consumption of wheat or wheat ATIs increases intestinal inflammation in mice with colitis, via TLR4, and alters their fecal microbiota. Wheat-based, ATI-containing diets therefore activate TLR4 signaling and promote intestinal dysbiosis.

Overexpressed FOXO3 improves inflammatory status in mice by affecting NLRP3-mediated cell coronation in necrotizing colitis mice

ObjectiveTo investigate the relationship between FOXO3 overexpression and NLRP3 and explore the effect of FOXO3 on necrotizing colitis. Methods100 clean grade newborn SD (Sprague Dawley) rats were randomly divided into 4 groups: NEC group, NEC + FOXO3a group, NEC + NC group and control group. NEC rat model was established by hypoxia + hypothermia stimulation; HE staining was used for detection of the inflammation of intestinal tissue. The histological scores of intestinal tissues were histologically scored, generally, there were three types of inflammatory scoring systems including anatomically based systems, severity-based systems and quality of life systems (Lim et al., 2015) and in this study we utilized severity-based systems by HE staining. Human intestinal epithelial cell line was transfected with recombinant plasmid overexpressing FOXO3a and recombinant plasmid overexpressing NLRP3, and divided into control group, LPS group, LPS + NC group, LPS + FOXO3a group and LPS + FOXO3a + NLRP3 group; Caspase-1 was used for the detection of pyroptosis. The expressions of FOXO3a, NLRP3, cleaved Caspase-1 and the expression of TLR4 in TLR4 signaling pathway were detected by RT-qPCR and WB. IL-1β, IL-6, IL-18 and TNF-α were detected by ELISA. Results(1) FOXO3a is under-expressed and NLRP3 is highly expressed in NEC neonatal rat intestinal tissue.(2) The inflammatory condition of intestinal tissue in NEC + FOXO3a group was improved compared with NEC group (P < 0.05).(3) FOXO3a was highly expressed in NEC + FOXO3a group. The expression of IL-1β, IL-6, IL-18, SOD and MDA in NEC + FOXO3a group was lower than that in NEC group.(4) The expression of IL-1β, IL-6, IL-18, SOD and MDA in intestinal epithelial cells of LPS + FOXO3a group was lower than other groups.(5) Overexpression of FOXO3a inhibits LPS-induced pyroptotic cell death in intestinal epithelial cells by inhibiting NLRP3. ConclusionOverexpression of FOXO3 in mice with necrotizing colitis can improve inflammatory conditions in mice by affecting NLRP3-mediated cell caking.

Dapsone reduced acetic acid-induced inflammatory response in rat colon tissue through inhibition of NF-kB signaling pathway

Aim: The purpose of this study is to examine the protective effects of Dapsone on inflammation of intestinal tissue through inhibition of NF-kB pathway in acetic acid-induced colitis in rats.Methods: Acute colitis was produced by intra-rectal instillation of 2 mL of 4% acetic acid diluted in normal saline. Then, two hours after induction of colitis, DMSO as vehicle, dexamethasone (2 mg/kg) and dapsone (12.5 mg/kg) were given to the animals intraperitoneally (i.p.) and continued for five following days. Evaluation of macroscopic and microscopic damages were done. Myeloid peroxidase enzyme (MPO) activity was measured by a biochemical technique. Moreover, tumor necrosis factor-α (TNF-α) activity was identified by ELISA, and the expression level of pNF-kB protein was evaluated by immunohistochemistry (IHC).Results: Dexamethasone (2 mg/kg) and dapsone (12.5 mg/kg) decreased the macroscopic and microscopic damages compared with acetic acid group (p ˂ .001). Additionally, these agents decreased the activity of MPO (p ˂ .001), TNF-α (p ˂ .001) and the expression level of p-NF-kB (p ˂ .001) in rat colon tissue compared with the acetic acid group.Conclusion: It is proposed that the anti-inflammatory activity of dapsone on acetic acid-induced colitis in rats may involve the inhibition of NF-kB pathway.

Structural insights on P31-43, a gliadin peptide able to promote an innate but not an adaptive response in celiac disease.

Inflammation of intestinal tissue in patients affected by celiac disease (CD) originates from the adaptive and innate immune responses elicited by the undigested gliadin fragments through molecular mechanisms not yet completely described. Undigested A-gliadin peptide P31-43 is central to CD pathogenesis, entering enterocytes in vesicular compartments by endocytosis and inducing an innate immune response in CD intestinal mucosa. This study focused on the reasons why P31-43 does not behave as adaptive immunogenic agent. Once obtained by NMR analysis, the three-dimensional model of P31-43 was used to implement a series of in silico experiments aimed to explore the ability of the peptide to interact with HLA-DQ2 and the corresponding receptor onto T cells. Our results show that P31-43 is a poor ligand for DQ2 and/or T-cell receptor. This study was also aimed to investigate, from a structural point of view, the previous experimental findings by which P31-43 is able to enhance the phosphorylation level of the protein ERK2, while some P31-43 Ala-mutants decrease or totally inhibit that process. The molecular models of P31-43, P31-43 P36A, and F37A mutants were used for in silico docking experiments onto the ERK2 structure. The experiments support the hypothesis that P31-43 F37A works as an ERK2 phosphorylation inhibitor because it binds to the ERK2 phosphorylation site. This study reports on the structural properties of so far never NMR characterized gliadin peptides relevant in CD and explores details about their mechanisms of action.