?-arrestin-2 enhances intestinal epithelial apoptosis in necrotizing enterocolitis.
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ABSTRACT:
SUBMITTER: Fu D
PROVIDER: S-EPMC6814604 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
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Project description:BackgroundNecrotizing enterocolitis (NEC) remains one of the overall leading causes of death in premature infants, and the pathogenesis is unpredictable and not well characterized. The aim of our study was to determine the molecular phenotype of NEC via transcriptomic and epithelial cell-specific epigenomic analysis, with a specific focus on DNA methylation.MethodsUsing laser capture microdissection, epithelial cell-specific methylation signatures were characterized by whole-genome bisulfite sequencing of ileal and colonic samples at the time of surgery for NEC and after NEC had healed at reanastomosis (n?=?40). RNA sequencing was also performed to determine the transcriptomic profile of these samples, and a comparison was made to the methylome data.ResultsWe found that surgical NEC has a considerable impact on the epigenome by broadly increasing DNA methylation levels, although these effects are less pronounced in genomic regions associated with the regulation of gene expression. Furthermore, NEC-related DNA methylation signatures were influenced by tissue of origin, with significant differences being noted between colon and ileum. We also identified numerous transcriptional changes in NEC and clear associations between gene expression and DNA methylation.ConclusionsWe have defined the intestinal epigenomic and transcriptomic signatures during surgical NEC, which will advance our understanding of disease pathogenesis and may enable the development of novel precision medicine approaches for NEC prediction, diagnosis and phenotyping.
| S-EPMC7730811 | biostudies-literature
Project description:Necrotizing enterocolitis (NEC) is the most devastating intestinal disease affecting preterm infants. In addition to being associated with short term mortality and morbidity, survivors are left with significant long term sequelae. The cost of caring for these infants is high. Epidemiologic evidence suggests that use of antibiotics and type of feeding may cause an intestinal dysbiosis important in the pathogenesis of NEC, but the contribution of specific infectious agents is poorly understood. Fecal samples from preterm infants ? 32 weeks gestation were analyzed using 16S rRNA based methods at 2, 1, and 0 weeks, prior to diagnosis of NEC in 18 NEC cases and 35 controls. Environmental factors such as antibiotic usage, feeding type (human milk versus formula) and location of neonatal intensive care unit (NICU) were also evaluated. Microbiota composition differed between the three neonatal units where we observed differences in antibiotic usage. In NEC cases we observed a higher proportion of Proteobacteria (61%) two weeks and of Actinobacteria (3%) 1 week before diagnosis of NEC compared to controls (19% and 0.4%, respectively) and lower numbers of Bifidobacteria counts and Bacteroidetes proportions in the weeks before NEC diagnosis. In the first fecal samples obtained during week one of life we detected a novel signature sequence, distinct from but matching closest to Klebsiella pneumoniae, that was strongly associated with NEC development later in life. Infants who develop NEC exhibit a different pattern of microbial colonization compared to controls. Antibiotic usage correlated with these differences and combined with type of feeding likely plays a critical role in the development of NEC.
| S-EPMC3875440 | biostudies-literature
Project description:Necrotizing enterocolitis (NEC) is a leading cause of mortality in preterm newborns. Intestinal barrier dysfunction is one key event in NEC pathogenesis. Human β-defensin-3 (hBD3), one member of cationic host defence peptides, was reported to reduce the development of necrotizing enterocolitis in a neonatal rat model. And autophagy was induced in the intestine of human and animals with NEC. We hypothesized that regulation of autophagy might play a critical role in hBD3-mediated protection against NEC injury. Autophagy activity was evaluated both in intestinal epithelial cells and in NEC models. Newborn Sprague-Dawley rats were divided randomly into four groups: Control + NS, Control + rapamycin, NEC + NS, and NEC + hBD3. Body weight, histological score, survival time, enterocyte migration and mucosal barrier were recorded. Our results showed that hBD3 pretreatment could effectively inhibit autophagy activity in cultured IEC-6 and Caco2 enterocytes, and CXCR4 might be involved in hBD3-mediated autophagy suppression. Moreover, hBD3-induced inhibition of autophagy significantly promoted the intestinal epithelial cell migration by wound healing assay and transwell migration assay. In the rat model of NEC, hBD3 could noticeably reduce the expression of autophagy-activated proteins, down-regulate the expression of inflammatory mediators, and promote the mucosal integrity. Our data suggest an additional role of hBD3-mediated protection against intestinal mucosal injury: inhibition of over-activated autophagy in enterocytes.
| S-EPMC6934505 | biostudies-literature
Project description:Necrotizing enterocolitis (NEC) involves intestinal epithelial damage and inflammatory response and is associated with high morbidity and mortality in infants. To improve therapeutic prospects, elucidating underlying molecular mechanisms of intestinal epithelial damage during NEC is of the essence. Poly (ADP-ribose) polymerase 1 (PARP1)-dependent parthanatos is a programmed inflammatory cell death. In the present study, the presence of parthanatos-associated proteins PARP1 and poly (ADP-ribose) (PAR), along with high expression of DNA damage-associated biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and phosphorylation of histone H2AX (γH2AX), were discovered in the intestinal tissues of NEC infants. Additionally, the upregulated expression of PARP1 and PAR in NEC intestinal tissues correlated distinctly with clinical indices indicative of NEC incidence and severity. Furthermore, we demonstrated that inhibiting the expression of parthanatos-associated proteins, by either pharmacological blockage using 3-aminobenzamide (3-AB), an inhibitor of PARP1, or genetic knockout using Parp1-deficient mice, resulted in substantial improvements in both histopathological severity scores associated with intestinal injury and inflammatory reactions. Moreover, in an in vitro NEC model, reactive oxygen species (ROS)-induced DNA damage promoted the formation of PAR and nuclear translocation of apoptosis-inducing factor (AIF), thus activating PARP1-dependent parthanatos in Caco-2 cells and human intestinal organoids. Our work verifies a previously unexplored role for parthanatos in intestinal epithelial damage during NEC and suggests that inhibition of parthanatos may serve as a potential therapeutic strategy for intervention of NEC.
| S-EPMC11291915 | biostudies-literature
Project description:Decreased intestinal perfusion may contribute to the development of necrotizing enterocolitis (NEC). Vascular endothelial growth factor (VEGF) is an angiogenic protein necessary for the development and maintenance of capillary networks. Whether VEGF is dysregulated in NEC remains unknown.The objective of this study was to determine whether intestinal VEGF expression is altered in a neonatal mouse model of NEC and in human NEC patients.We first assessed changes of intestinal VEGF mRNA and protein in a neonatal mouse NEC model before significant injury occurs. We then examined whether exposure to formula feeding, bacterial inoculation, cold stress and/or intermittent hypoxia affected intestinal VEGF expression. Last, we visualized VEGF protein in intestinal tissues of murine and human NEC and control cases by immunohistochemistry.Intestinal VEGF protein and mRNA were significantly decreased in pups exposed to the NEC protocol compared to controls. Hypoxia, cold stress and commensal bacteria, when administered together, significantly downregulated intestinal VEGF expression, while they had no significant effect when given alone. VEGF was localized to a few single intestinal epithelial cells and some cells of the lamina propria and myenteric plexus. VEGF staining was decreased in murine and human NEC intestines when compared to control tissues.Intestinal VEGF protein is reduced in human and experimental NEC. Decreased VEGF production might contribute to NEC pathogenesis.
| S-EPMC4354688 | biostudies-literature
Project description:Although currently available data are variable, it appears that the incidence of surgical necrotizing enterocolitis (NEC) has not decreased significantly over the past decade. Pneumoperitoneum and clinical deterioration despite maximal medical therapy remain the most common indications for operative treatment. Robust studies linking outcomes with specific indications for operation are lacking. Promising biomarkers for severe NEC include fecal calprotectin and S100A12; serum fatty acid-binding protein; and urine biomarkers. Recent advances in ultrasonography make this imaging modality more useful in identifying surgical NEC and near-infrared spectroscopy (NIRS) is being actively studied. Another fairly recent finding is that regionalization of care for infants with NEC likely improves outcomes. The neurodevelopmental outcomes after surgical treatment are known to be poor. A randomized trial near completion will provide robust data regarding neurodevelopmental outcomes after laparotomy versus drainage as the initial operative treatment for severe NEC.
| S-EPMC5777619 | biostudies-other
Project description:Little is known about factors that regulate intestinal epithelial differentiation; microbial recognition receptors such as Toll-like receptor (TLR)4 might be involved. We investigated whether intestinal TLR4 regulates epithelial differentiation and is involved in development of necrotizing enterocolitis (NEC) of the immature intestine.Mice with conditional disruption of TLR4 in the intestinal epithelium and TLR4 knockout (TLR4(-/-)) mice were generated by breeding TLR4(loxp/loxp) mice with villin-cre and Ella-cre, respectively. Enterocytes that did not express or overexpressed TLR4 were created by lentiviral or adenoviral transduction. Intestinal organoids were cultured on tissue matrices. Bile acids were measured by colorimetric assays, and microbial composition was determined by 16S pyrosequencing. NEC was induced in 7- to 10-day-old mice by induction of hypoxia twice daily for 4 days.TLR4(-/-) mice and mice with enterocyte-specific deletion of TLR4 were protected from NEC; epithelial differentiation into goblet cells was increased via suppressed Notch signaling in the small intestinal epithelium. TLR4 also regulates differentiation of goblet cells in intestinal organoid and enterocyte cell cultures; differentiation was increased on deletion of TLR4 and restored when TLR4 was expressed ectopically. TLR4 signaling via Notch was increased in intestinal tissue samples from patients with NEC, and numbers of goblet cells were reduced. 16S pyrosequencing revealed that wild-type and TLR4-deficient mice had similar microbial profiles; increased numbers of goblet cells were observed in mice given antibiotics. TLR4 deficiency reduced levels of luminal bile acids in vivo, and addition of bile acids to TLR4-deficient cell cultures prevented differentiation of goblet cells.TLR4 signaling and Notch are increased in intestinal tissues of patients with NEC and required for induction of NEC in mice. TLR4 prevents goblet cell differentiation, independently of the microbiota. Bile acids might initiate goblet cell development.
| S-EPMC3584415 | biostudies-literature
Project description:Importance:Necrotizing enterocolitis (NEC) in preterm infants is an often-fatal gastrointestinal tract emergency. A robust NEC biomarker that is not confounded by sepsis could improve bedside management, lead to lower morbidity and mortality, and permit patient selection in randomized clinical trials of possible therapeutic approaches. Objective:To evaluate whether aberrant intestinal alkaline phosphatase (IAP) biochemistry in infant stool is a molecular biomarker for NEC and not associated with sepsis. Design, Setting, and Participants:This multicenter diagnostic study enrolled 136 premature infants (gestational age, <37 weeks) in 2 hospitals in Louisiana and 1 hospital in Missouri. Data were collected and analyzed from May 2015 to November 2018. Exposures:Infant stool samples were collected between 24 and 40 or more weeks postconceptual age. Enrolled infants underwent abdominal radiography at physician and hospital site discretion. Main Outcomes and Measures:Enzyme activity and relative abundance of IAP were measured using fluorometric detection and immunoassays, respectively. After measurements were performed, biochemical data were evaluated against clinical entries from infants' hospital stay. Results:Of 136 infants, 68 (50.0%) were male infants, median (interquartile range [IQR]) birth weight was 1050 (790-1350) g, and median (IQR) gestational age was 28.4 (26.0-30.9) weeks. A total of 25 infants (18.4%) were diagnosed with severe NEC, 19 (14.0%) were suspected of having NEC, and 92 (66.9%) did not have NEC; 26 patients (19.1%) were diagnosed with late-onset sepsis, and 14 (10.3%) had other non-gastrointestinal tract infections. For severe NEC, suspected NEC, and no NEC samples, median (IQR) fecal IAP content, relative to the amount of IAP in human small intestinal lysate, was 99.0% (51.0%-187.8%) (95% CI, 54.0%-163.0%), 123.0% (31.0%-224.0%) (95% CI, 31.0%-224.0%), and 4.8% (2.4%-9.8%) (95% CI, 3.4%-5.9%), respectively. For severe NEC, suspected NEC, and no NEC samples, median (IQR) enzyme activity was 183 (56-507) ?mol/min/g (95% CI, 63-478 ?mol/min/g) of stool protein, 355 (172-608) ?mol/min/g (95% CI, 172-608 ?mol/min/g) of stool protein, and 613 (210-1465) ?mol/min/g (95% CI, 386-723 ?mol/min/g) of stool protein, respectively. Mean (SE) area under the receiver operating characteristic curve values for IAP content measurements were 0.97 (0.02) (95% CI, 0.93-1.00; P?<?.001) at time of severe NEC, 0.97 (0.02) (95% CI, 0.93-1.00; P?<?.001) at time of suspected NEC, 0.52 (0.07) (95% CI, 0.38-0.66; P?=?.75) at time of sepsis, and 0.58 (0.08) (95% CI, 0.42-0.75; P?=?.06) at time of other non-gastrointestinal tract infections. Mean (SE) area under the receiver operating characteristic curve values for IAP activity were 0.76 (0.06) (95% CI, 0.64-0.86; P?<?.001), 0.62 (0.07) (95% CI, 0.48-0.77; P?=?.13), 0.52 (0.07) (95% CI, 0.39-0.67; P?=?.68), and 0.57 (0.08) (95% CI, 0.39-0.69; P?=?.66), respectively. Conclusions and Relevance:In this diagnostic study, high amounts of IAP protein in stool and low IAP enzyme activity were associated with diagnosis of NEC and may serve as useful biomarkers for NEC. Our findings indicated that IAP biochemistry was uniquely able to distinguish NEC from sepsis.
| S-EPMC6902776 | biostudies-literature
Project description:Necrotizing enterocolitis (NEC) is a devastating disease of premature infants with high mortality rate, indicating the need for precision treatment. NEC is characterized by intestinal inflammation and ischemia, as well derangements in intestinal microcirculation. Remote ischemic conditioning (RIC) has emerged as a promising tool in protecting distant organs against ischemia-induced damage. However, the effectiveness of RIC against NEC is unknown. To address this gap, we aimed to determine the efficacy and mechanism of action of RIC in experimental NEC. NEC was induced in mouse pups between postnatal day (P) 5 and 9. RIC was applied through intermittent occlusion of hind limb blood flow. RIC, when administered in the early stages of disease progression, decreases intestinal injury and prolongs survival. The mechanism of action of RIC involves increasing intestinal perfusion through vasodilation mediated by nitric oxide and hydrogen sulfide. RIC is a viable and non-invasive treatment strategy for NEC.
| S-EPMC7532542 | biostudies-literature
Project description:Necrotizing enterocolitis (NEC) is a deadly intestinal inflammatory disorder that primarily affects premature infants and lacks adequate therapeutics. Interleukin (IL)-22 plays a critical role in gut barrier maintenance, promoting epithelial regeneration, and controlling intestinal inflammation in adult animal models. However, the importance of IL-22 signaling in neonates during NEC remains unknown. We investigated the role of IL-22 in the neonatal intestine under homeostatic and inflammatory conditions by using a mouse model of NEC. Our data reveal that Il22 expression in neonatal murine intestine is negligible until weaning, and both human and murine neonates lack IL-22 production during NEC. Mice deficient in IL-22 or lacking the IL-22 receptor in the intestine display a similar susceptibility to NEC, consistent with the lack of endogenous IL-22 during development. Strikingly, treatment with recombinant IL-22 during NEC substantially reduces inflammation and enhances epithelial regeneration. These findings may provide a new therapeutic strategy to attenuate NEC.
| S-EPMC8233697 | biostudies-literature