Targeted metabolomics unravels altered phenylalanine levels in piglets receiving total parenteral nutrition.

Parenteral nutrition, received by many patients with intestinal failure, can induce hepatobiliary complications, which is termed as parenteral nutrition-associated liver disease (PNALD). The spectrum of PNALD ranges from cholestasis and steatosis to fibrosis and cirrhosis. Although many factors contribute to the pathogenesis of PNALD, the underlying mechanisms remain unclear. In this study, we performed targeted metabolomics to characterize the metabolomic profile in neonatal piglets receiving total parenteral nutrition (TPN) or enteral nutrition (EN) for 1 or 2 weeks. Overall, the metabolomic signature of TPN groups differed from EN groups at both time points. Among the 20 acylcarnitines identified, a majority of them were significantly reduced in TPN groups. KEGG pathway analysis showed that phenylalanine metabolism-associated pathways were dysregulated accompanied by more progressive liver steatosis associated with TPN. Next, we evaluated phenylalanine catabolism and its association with fatty acid oxidation in piglets and rats with PNALD. We showed that the hepatic expression of phenylalanine-degrading enzyme phenylalanine hydroxylase (PAH) was reduced and systemic phenylalanine levels were increased in both animal models of PNALD. Moreover, carnitine palmitoyltransferase 1A, a central regulator of fatty acid oxidation, was downregulated and its expression was negatively correlated with phenylalanine levels in TPN-fed animals. To explore the effects of phenylalanine accumulation on lipid metabolism, we treated HepG2 cells with phenylalanine co-cultured with sodium palmitate or soybean oil emulsion to induce lipid accumulation. We found that phenylalanine treatment exacerbated lipid accumulation by inhibiting fatty acid oxidation without affecting fatty acid synthesis. In summary, our findings establish a pathogenic role of increased phenylalanine levels in driving liver steatosis, linking dysregulation of phenylalanine catabolism with lipid accumulation in the context of PNALD.

Production of Tone 2 in disyllabic words in Mandarin Chinese speaking children aged 3-5 with a cochlear implant and a contralateral hearing aid.

To investigate Mandarin Tone 2 production of disyllabic words of prelingually deafened children with a cochlear implant (CI) and a contralateral hearing aid (HA) and to evaluate the relationship between their demographic variables and tone-production ability. Thirty prelingually Mandarin-speaking preschoolers with CI+HA and 30 age-matched normal-hearing (NH) children participated in the study. Fourteen disyllabic words were recorded from each child. A total of 840 tokens (14 × 60) were then used in tone-perception tests in which four speech therapists participated. The production of T2-related disyllabic words of the bimodal group was significantly worse than that of the NH group, as reflected in the overall accuracy (88.57% ± 16.31% vs 99.29% ± 21.79%, p < 0.05), the accuracy of T1+T2 (93.33% vs 100%), the accuracy of T2+T1 (66.67 ± 37.91% vs 98.33 ± 9.13%), and the accuracy of T2+T4 (78.33 ± 33.95% vs 100%). In addition, the bimodal group showed significantly inferior production accuracy of T2+T1 than T2+T2 and T3+T2, p < 0.05. Both bimodal age and implantation age were significantly negatively correlated with the overall production accuracy, p < 0.05. For the error patterns, bimodal participants experienced more errors when T2 was in the first position of the tone combination, and T2 was most likely to be mispronounced as T1 and T3. Bimodal patients aged 3-5 have T2-related disyllabic lexical tone production defects, and their performances are related to tone combination, implantation age, and bimodal age.

Targeted Metabolomics Reveals Birth Screening Biomarkers for Biliary Atresia in Dried Blood Spots.

Early diagnosis and timely surgical Kasai portoenterostomy greatly improve the survival of patients with biliary atresia (BA), a neonatal cholestatic disease, which has encouraged investigators to develop newborn screening for BA. In this study, we used ultraperformance liquid chromatography-triple quadrupole mass spectrometry-based targeted metabolomics profiling to identify potential BA biomarkers in dried blood spots (DBS) collected from BA patients (n = 21) and healthy controls (n = 100). A distinctive metabolic profile comprising eight significantly differentially expressed metabolites, taurohyocholic acid (THCA), glutamic acid, 2-hydroxyglutaric acid, ketoleucine, indoleacetic acid, alpha-ketoisovaleric acid, glycocholic acid, and taurocholic acid (TCA), clearly distinguished BA infants from control neonates. Three metabolites, THCA, 2-hydroxyglutaric acid, and indoleacetic acid, were selected using linear regression and receiver operating characteristic (ROC) curve analysis and model construction. The area under the ROC curve for this model to discriminate between BA and comparison infants was 0.938 (95% confidence interval, CI: 0.874-1.000). A cutoff value of -0.336 produced a sensitivity of 90.48% (95% CI: 69.62% - 98.83%) and specificity of 92% (95% CI: 84.84% - 96.48%). In conclusion, the results suggest that metabolic markers in DBS obtained from newborns have a great potential for BA screening.

Role of the Gut Microbiota in Parenteral Nutrition-Associated Liver Disease: From Current Knowledge to Future Opportunities.

Parenteral nutrition-associated liver disease (PNALD) refers to a spectrum of conditions that can develop cholestasis, steatosis, fibrosis, and cirrhosis in the setting of parenteral nutrition (PN) use. Patient risk factors include short bowel syndrome, bacterial overgrowth and translocation, disturbance of hepatobiliary circulation, and lack of enteral feeding. A growing body of evidence suggests an intricate linkage between the gut microbiota and the pathogenesis of PNALD. In this review, we highlight current knowledge on the taxonomic and functional changes in the gut microbiota that might serve as noninvasive biomarkers. We also discuss the function of microbial metabolites and associated signaling pathways in the pathogenesis of PNALD. By providing the perspectives of microbiota-host interactions in PNALD for basic and translational research and summarizing current limitations of microbiota-based approaches, this review paves the path for developing novel and precise microbiota-based therapies in PNALD.

Diagnostic values of plasma matrix metalloproteinase-7, interleukin-8, and gamma-glutamyl transferase in biliary atresia.

Biliary atresia (BA) is a severe cholestatic liver disease in children featuring cholestasis and liver fibrosis. The early diagnosis of BA is still challenging. This study aimed to evaluate the diagnostic values of matrix metalloprotease-7 (MMP-7), interleukin-8 (IL-8), and gamma-glutamyl transferase (GGT) in BA. Infants diagnosed with BA and non-BA between 2013 and 2018 were retrospectively analyzed. Plasma levels of MMP-7, IL-8, and GGT were measured in these infants. The receiver operating characteristic (ROC) curves and area under the ROC curve (AUC) were used to assess the diagnostic values of MMP-7, IL-8, and GGT. The expression of MMP-7 and IL-8 in the livers was detected by immunofluorescence staining. A total of 229 infants were enrolled in this study: 156 BA infants and 73 non-BA infants including 16 ones with infantile hepatitis syndrome. The plasma levels of MMP-7, IL-8, and GGT in BA infants had a median of 11.8 ng/mL (interquartile range, IQR: 5.3-57.5), 1.5 ng/mL (IQR: 1.0-2.8), and 381.0 U/L (IQR: 197.0-749.0), respectively, which were higher than non-BA subjects [MMP-7, 4.4 ng/mL (IQR: 3.3-6.1); IL-8, 0.7 ng/mL (IQR: 0.5-1.0); GGT, 59.0 U/L (IQR: 26.0-124.0)]. The AUC values of MMP-7, IL-8, and GGT for the diagnosis of BA were 0.8035, 0.8083, and 0.9126, respectively. The AUC values of MMP-7 + IL-8, MMP-7 + GGT, IL-8 + GGT, and MMP-7 + IL-8 + GGT for the diagnosis of BA were 0.8248, 0.9382, 0.9168, and 0.9392, respectively. The AUC values of MMP-7, IL-8, and GGT for differentiating BA infants with cholic stool from non-BA infants with cholic stool were 0.8006, 0.8258, and 0.9141, respectively. The expression of MMP-7 and IL-8 was increased in the cholangiocytes in BA livers.   Conclusion: Plasma MMP-7, IL-8, and GGT alone or a combination of them has good accuracy to differentiate BA from non-BA and may be reliable biomarkers for BA. What is Known: • Biliary atresia (BA) is a severe cholestatic liver disease in children featuring cholestasis and progressive liver fibrosis. • Although early diagnosis of BA is crucial for good outcomes, it remains a clinical challenge. What is New: • Plasma MMP-7, IL-8, and GGT alone or a combination of them has good accuracy to differentiate BA from non-BA. • Plasma MMP-7, IL-8, and GGT have good accuracy for differentiating BA infants with cholic stool from non-BA infants with cholic stool.

A nonbile acid farnesoid X receptor agonist tropifexor potently inhibits cholestatic liver injury and fibrosis by modulating the gut-liver axis.

BACKGROUND & AIMS: Tropifexor (TXR) is a novel nonbile acid that acts as an agonist of farnesoid X receptor (FXR). TXR is currently in Phase 2 trials for the treatment of non-alcoholic steatohepatitis (NASH). Herein, we report the impact of TXR on in a piglet model in which cholestatic liver damage and fibrosis where induced by bile duct ligation (BDL). METHODS: The piglets received BDL and TXR for 2 wk. Hepatic, portal and colonic bile acid and amino acid profiles and gut microbiome were analysed. Portal fibroblast growth factor (FGF) 19 levels were measured using an enzyme-linked immunosorbent assay (ELISA). RESULTS: We first showed that bile acid metabolism and signalling are dysfunctional in patients with biliary atresia. Next, we observed that TXR potently suppresses BDL-induced liver injury, fibrosis and ductular reaction in piglets. Within the ileum, TXR enhances FGF19 expression and subsequently increases portal FGF19 levels. In the liver, TXR promotes the expression of small heterodimer partner (SHP) and inhibits cholesterol 7α-hydroxylase (CYP7A1). Additionally, TXR increases the abundance of bile acid-biotransforming bacteria in the distal ileum and alters the composition of amino acids in the colon. Lastly, TXR ameliorates intestinal barrier injury in piglets subjected to BDL. CONCLUSION: TXR potently ameliorated cholestatic liver injury and fibrosis by modulating the gut-liver axis in piglets. It supports the clinical evaluation of TXR as a therapeutic strategy for cholestatic liver diseases, such as biliary atresia.

The Farnesoid X Receptor Agonist Tropifexor Prevents Liver Damage in Parenteral Nutrition-fed Neonatal Piglets.

OBJECTIVES: Intestinal failure-associated liver disease (IFALD) is a life-threatening complication for patients with intestinal failure who receive long-term parenteral nutrition (PN). We evaluated the effects of the farnesoid X receptor agonist tropifexor on a neonatal piglet model of IFALD fed with PN. METHODS: The piglets received PN and tropifexor for 14 days, then levels of liver enzymes, bile acid metabolism, inflammation, and intestinal barrier markers were assessed using quantitative real-time PCR. Fibroblast growth factor (FGF) 19 serum levels were determined using enzyme-linked immunosorbent assays. Bile acids were determined in liver, serum, and intestinal contents, and the microbiome was sequenced in different intestinal segments. RESULTS: The PN model was established in newborn piglets. The levels of serum liver enzymes, pro-inflammatory factors, and oxidative stress increased in the livers of piglets fed with PN, but not in those fed with PN and tropifexor. Tropifexor stimulated FGF19 expression in ileal epithelial cells, increased portal FGF19 levels, then inhibited cholesterol 7α-hydroxylase expression in the liver. Tropifexor increased the relative abundance of bacteria associated with bile salt hydrolase and 7α-dehydrogenation in the contents of ileum and altered the composition of bile acids in serum, liver, and intestinal contents. Tropifexor also inhibited intestinal inflammation, alleviated intestinal mucosal atrophy, and improved the intestinal barrier. CONCLUSIONS: Tropifexor might prevent liver damage in neonatal piglets receiving PN by altering the composition of intestinal microbiota and bile acids. Tropifexor also alleviates intestinal inflammation and preserves the intestinal barrier.

Variants in the Enteric Smooth Muscle Actin γ-2 Cause Pediatric Intestinal Pseudo-obstruction in Chinese Patients.

OBJECTIVES: Pediatric intestinal pseudo-obstruction (PIPO) is a severe gastrointestinal disorder occurring in children, leading to failure to thrive, malnutrition, and long-term parenteral nutrition dependence. Enteric smooth muscle actin γ-2 (ACTG2) variants have been reported to be related to the pathogenesis of PIPO. This study aimed to determine the presence of ACTG2 variants in Chinese PIPO patients. METHODS: Whole-exome sequencing was performed using samples from 39 recruited patients, whereas whole ACTG2 Sanger sequencing was performed using samples from 2 patients. Published data was reviewed to determine the number of pathogenic variants and the genotype related to ACTG2 variants in the Chinese population. RESULTS: A total of 21 Chinese probands were found to carry heterozygous missense variants of ACTG2, among which 20 were de novo. Fifteen probands had p.Arg257 variants (c.770G>A and c.769C>T), and the other 2 probands had c.533G>A (p.Arg178His) and c.443G>T (p.Arg148Leu) variants. Four probands had novel variants c.337C>T (p.Pro113Ser), c.588G>C (p.Glu196Asp), c.734A>G (p.Asp245Gly), and c.553G>T (p.Asp185Tyr). CONCLUSIONS: Variants affecting codon 257 of ACTG2 protein sequence appeared to be frequent in both Chinese and Caucasian PIPO patients, whereas p.Arg178 variants were less common in Chinese patients compared with Caucasian patients. The 4 novel variants in ACTG2 were also found to be related to Chinese PIPO.

Long Noncoding RNA H19 Contributes to Cholangiocyte Proliferation and Cholestatic Liver Fibrosis in Biliary Atresia.

Biliary atresia (BA) is a neonatal liver disease featuring cholestasis and severe liver fibrosis (LF). Despite advances in the development of surgical treatment, lacking an early diagnostic marker and intervention of LF invariably leads to death from end-stage liver disease in the early years of life. We previously reported that knockout of sphingosine 1-phosphate receptor 2 (S1PR2) protected mice from bile duct ligation (BDL)-induced cholangiocyte proliferation and LF. Our recent studies further showed that both hepatic and serum exosomal long noncoding RNA H19 (lncRNAH19) levels are correlated with cholestatic injury in multidrug resistance 2 knockout (Mdr2-/- ) mice. However, the role of lncRNAH19 in BA progression remains unclear. Here, we show that both hepatic and serum exosomal H19 levels are positively correlated with severity of fibrotic liver injuries in BA patients. H19 deficiency protects mice from BDL-induced cholangiocyte proliferation and LF by inhibiting bile-acid-induced expression and activation of S1PR2 and sphingosine kinase 2 (SphK2). Furthermore, H19 acts as a molecular sponge for members of the microRNA let-7 family, which results in up-regulation of high-mobility group AT-hook 2 (HMGA2), a known target of let-7 and enhancement of biliary proliferation. Conclusion: These results indicate that H19 plays a critical role in cholangiocyte proliferation and cholestatic liver injury in BA by regulating the S1PR2/SphK2 and let-7/HMGA2 axis. Serum exosomal H19 may represent a noninvasive diagnostic biomarker and potential therapeutic target for BA.

Long non-coding RNA H19 deficiency ameliorates bleomycin-induced pulmonary inflammation and fibrosis.

BACKGROUND: The poor understanding of pathogenesis in idiopathic pulmonary fibrosis (IPF) impaired development of effective therapeutic strategies. The aim of the current study is to investigate the roles of long non-coding RNA H19 (lncRNA H19) in the pulmonary inflammation and fibrosis of IPF. METHODS: Bleomycin was used to induce pulmonary inflammation and fibrosis in mice. The mRNAs and proteins expression in lung tissues was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. H19 knockout (H19-/-) mice were generated by CRISPR/Cas9. RESULTS: The expression of H19 mRNA was up-regulated in fibrotic lungs patients with IPF as well as in lungs tissues that obtained from bleomycin-treated mice. H19-/- mice suppressed bleomycin-mediated pulmonary inflammation and inhibited the Il6/Stat3 signaling. H19 deficiency ameliorated bleomycin-induced pulmonary fibrosis and repressed the activation of TGF-ß/Smad and S1pr2/Sphk2 in the lungs of bleomycin-treated mice. CONCLUSIONS: Our data suggests that H19 is a profibrotic lncRNA and a potential therapeutic target for IPF.

Krüppel-like factor 9 promotes neuroblastoma differentiation via targeting the sonic hedgehog signaling pathway.

BACKGROUND: Neuroblastoma (NB) is a deadly solid tumor of children. Krüppel-like factor 9 (KLF9) has prodifferentiation and tumor suppression functions in several types of cancers. Here, we aimed to investigate the effects of KLF9 on NB differentiation and growth and to elucidate the underlying mechanism. PROCEDURE: Sixty-five NB paraffin samples were assessed for expression levels of KLF9 and sonic hedgehog (SHH) signaling pathway proteins by immunohistochemistry. The associations between expression of KLF9 and the SHH pathway components and patients' clinicopathologic characteristics were estimated. The impacts of KLF9 on cell differentiation, proliferation, and invasion were investigated in two NB cell lines (SH-SY5Y and IMR32). Additionally, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were used to elucidate the mechanism by which KLF9 regulates SHH signaling. RESULTS: Differentiating NB specimens showed significantly higher KLF9 expression levels than undifferentiated/poorly differentiated ones. Moreover, increased KLF9 expression was associated with favorable prognoses in patients with NB. A negative correlation was found between KLF9 and SHH signaling expression levels in NB specimens. In vitro assays revealed that KLF9 promoted the differentiation of NB cells and inhibited their proliferation and invasion via suppression of the SHH pathway. Furthermore, KLF9 binding sites in the SHH promoter were identified by ChIP and luciferase reporter assays. CONCLUSIONS: KLF9 exerts prodifferentiation and growth-inhibition effects on NB via suppression of the SHH pathway, suggesting a potential role of KLF9 in NB therapy.

FXR agonist GW4064 improves liver and intestinal pathology and alters bile acid metabolism in rats undergoing small intestinal resection.

Mortality associated with liver disease has been observed in patients with short bowel syndrome (SBS); however, its mechanism remains unclear, but bile acid (BA) dysmetabolism has been proposed as a possible cause. The farnesoid X receptor (FXR) is the key regulator of BA synthesis. Here, we showed that, in a rat model of short bowel resection associated with liver disease (SBR-ALD), the BA composition of hepatic tissues reflected a larger proportion of primary and secondary unconjugated BAs, whereas that of the colon contents and serum showed an increased ratio of secondary unconjugated BAs. Both hepatic and intestinal regulation of BA synthesis was characterized by a blunted hepatic FXR activation response. The mRNA expression levels of cholesterol 7a-hydroxylase (CYP7A1), sterol 12a-hydroxylase (CYP8B1), and sterol 27 hydroxylase (CYP27A1), the key enzymes in BA synthesis, were upregulated. After intervention with the FXR agonist GW4064, both the liver histology and serum transaminase activity were improved, which demonstrated the attenuation of SBR-ALD. The BA compositions of hepatic tissue, the colon contents, and serum recovered and were closer to those of the sham group. The expression levels of hepatic FXR increased, and its target genes were activated. Consistent with this, the expression levels of CYP7A1, CYP8B1, and CYP27A1 were downregulated. Ileum tissue FXR and its target genes were slightly elevated. This study showed that the FXR agonist GW4064 could correct BA dysmetabolism to alleviate hepatotoxicity in SBR animals. GW4064 intervention resulted in a decrease in fecal bile excretion and elevated plasma/hepatic conjugated BA levels. GW4064 increased the reabsorption of conjugated BAs by inducing apical sodium-dependent bile salt transporter expression in the ileum. Concomitantly, FXR activation in the presence of GW4064 decreased BA production by repressing the expression of key synthetases, including CYP7A1, CYP8B1, and CYP27A1. These findings provide a clinical research direction for the prevention of liver disease in patients with SBS.NEW & NOTEWORTHY This study assessed the impact of treatment with GW4064, a farnesoid X receptor agonist, on the development of short bowel resection (SBR) associated with liver disease in a rat model of SBR. GW4064 was able to correct bile acid dysmetabolism and alleviate hepatotoxicity in SBR animals.

Supplementary choline attenuates olive oil lipid emulsion-induced enterocyte apoptosis through suppression of CELF1/AIF pathway.

Enterocyte apoptosis induced by lipid emulsions is a key cause of intestinal atrophy under total parenteral nutrition (TPN) support, and our previous work demonstrated that olive oil lipid emulsion (OOLE) could induce enterocyte apoptosis via CUGBP, Elav-like family member 1 (CELF1)/ apoptosis-inducing factor (AIF) pathway. As TPN-associated complications are partially related to choline deficiency, we aimed to address whether choline supplementation could attenuate OOLE-induced enterocyte apoptosis. Herein we present evidence that supplementary choline exhibits protective effect against OOLE-induced enterocyte apoptosis both in vivo and in vitro. In a rat model of TPN, substantial reduction in apoptotic rate along with decreased expression of CELF1 was observed when supplementary choline was added to OOLE. In cultured Caco-2 cells, supplementary choline attenuated OOLE-induced apoptosis and mitochondria dysfunction by suppressing CELF1/AIF pathway. Compared to OOLE alone, the expression of CELF1 and AIF was significantly decreased by supplementary choline, whereas the expression of Bcl-2 was evidently increased. No obvious alterations were observed in Bax expression and caspase-3 activation. Mechanistically, supplementary choline repressed the expression of CELF1 by increasing the recruitment of CELF1 mRNA to processing bodies, thus resulting in suppression of its protein translation. Taken together, our data suggest that supplementary choline exhibits effective protection against OOLE-induced enterocyte apoptosis, and thus, it has the potential to be used for the prevention and treatment of TPN-induced intestinal atrophy.

Butyrate stimulates the growth of human intestinal smooth muscle cells by activation of yes-associated protein.

Intestinal smooth muscle cells play a critical role in the remodeling of intestinal structure and functional adaptation after bowel resection. Recent studies have shown that supplementation of butyrate (Bu) contributes to the compensatory expansion of a muscular layer of the residual intestine in a rodent model of short-bowel syndrome (SBS). However, the underlying mechanism remains elusive. In this study, we found that the growth of human intestinal smooth muscle cells (HISMCs) was significantly stimulated by Bu via activation of Yes-Associated Protein (YAP). Incubation with 0.5 mM Bu induced a distinct proliferative effect on HISMCs, as indicated by the promotion of cell cycle progression and increased DNA replication. Notably, YAP silencing by RNA interference or its specific inhibitor significantly abolished the proliferative effect of Bu on HISMCs. Furthermore, Bu induced YAP expression and enhanced the translocation of YAP from the cytoplasm to the nucleus, which led to changes in the expression of mitogenesis genes, including TEAD1, TEAD4, CTGF, and Cyr61. These results provide evidence that Bu stimulates the growth of human intestinal muscle cells by activation of YAP, which may be a potential treatment for improving intestinal adaptation.

miR-200b inhibits TNF-α-induced IL-8 secretion and tight junction disruption of intestinal epithelial cells in vitro.

Inflammatory bowel diseases (IBDs) are chronic, inflammatory disorders of the gastrointestinal tract with unclear etiologies. Intestinal epithelial cells (IECs), containing crypt and villus enterocytes, occupy a critical position in the pathogenesis of IBDs and are a major producer of immunoregulatory cytokines and a key component of the intact epithelial barrier. Previously, we have reported that miR-200b is involved in the progression of IBDs and might maintain the integrity of the intestinal epithelial barrier via reducing the loss of enterocytes. In this study, we further investigated the impact of miR-200b on intestinal epithelial inflammation and tight junctions in two distinct differentiated states of Caco-2 cells after TNF-α treatment. We demonstrated that TNF-α-enhanced IL-8 expression was decreased by microRNA (miR)-200b in undifferentiated IECs. Simultaneously, miR-200b could alleviate TNF-α-induced tight junction (TJ) disruption in well-differentiated IECs by reducing the reduction in the transepithelial electrical resistance (TEER), inhibiting the increase in paracellular permeability, and preventing the morphological redistribution of the TJ proteins claudin 1 and ZO-1. The expression levels of the JNK/c-Jun/AP-1 and myosin light chain kinase (MLCK)/phosphorylated myosin light chain (p-MLC) pathways were attenuated in undifferentiated and differentiated enterocytes, respectively. Furthermore, a dual-luciferase reporter gene detection system provided direct evidence that c-Jun and MLCK were the specific targets of miR-200b. Collectively, our results highlighted that miR-200b played a positive role in IECs via suppressing intestinal epithelial IL-8 secretion and attenuating TJ damage in vitro, which suggested that miR-200b might be a promising strategy for IBD therapy. NEW & NOTEWORTHY: This was the first time that the inhibitory role of miR-200b on intestinal epithelial inflammation and paracellular permeability has been reported. Moreover, we further divided the intestinal epithelial cells (IECs) into two differentiated conditions and investigated the distinct impacts of miR-200b. Finally, we put forward and proved that myosin light chain kinase (MLCK) was a novel target of miR-200b.

P38 MAPK Pharmacological Inhibitor SB203580 Alleviates Total Parenteral Nutrition-Induced Loss of Intestinal Barrier Function but Promotes Hepatocyte Lipoapoptosis.

BACKGROUND & AIMS: Our previous studies have provided evidence that p38 mitogen-activated protein kinase (MAPK) is involved in total parenteral nutrition (TPN)-associated complications, but its exact effects and mechanisms have not been fully understood. This study aimed to evaluate the roles of p38 MAPK inhibitor SB203580 in the TPN-induced loss of intestinal barrier function and liver disease. METHODS: A rodent model of TPN was used to analyze the roles of SB203580 in TPN-associated complications.Intestinal barrier function was evaluated by transepithelial electrical resistance (TER) and paracellular permeability in Caco-2 cells. The palmitic acid (PA) was used to induce hepatic lipoapoptosis in vitro. The lipoapoptosis was detected using Caspase-3/7 and lipid staining. RESULTS: In the present study, we showed that SB203580 treatment significantly suppressed TPN-mediated intestinal permeability in rats. SB203580 treatment significantly inhibited IL-1ß-induced an increase in tight junction permeability of Caco-2 cells via repressing the p38/ATF-2 signaling. Unexpectedly, SB203580 treatment enhanced hepatic lipoapoptosis in the model of TPN. Palmitic acid (PA)-induced hepatic lipoapoptosis in human liver cells was significantly augmented by the SB203580 treatment. CONCLUSIONS: We demonstrate that the p38 MAPK inhibitor SB203508 ameliorates intestinal barrier function but promotes hepatic lipoapoptosis in model of TPN.

Olive Oil-Supplemented Lipid Emulsion Induces CELF1 Expression and Promotes Apoptosis in Caco-2 Cells.

BACKGROUND AND AIMS: Parenterally-administered lipid emulsion (LE) is a key cause of enterocyte apoptosis under total parenteral nutrition, yet the pathogenesis has not been fully understood. CUGBP, Elav-like family member 1 (CELF1) has been recently identified as a crucial modulator of apoptosis, and thus this study sought to investigate its role in the LE-induced apoptosis in vitro. METHODS: Caco-2 cells were used as an in vitro model. The cells were treated with varying LEs derived from soybean oil, olive oil or fish oil, and changes in the apoptosis and CELF1 expression were assessed. Rescue study was performed using transient knockdown of CELF1 with specific siRNA prior to LE treatment. Regulation of CELF1 by LE treatment was studied using quantitative real-time PCR and Western blotting. RESULTS: All the LEs up-regulated CELF1expression and induced apoptosis, but only olive oil-supplemented lipid emulsion (OOLE)-induced apoptosis was attenuated by depletion of CELF1. Up-regulation of apoptosis-inducing factor (AIF) was involved in OOLE-induced CELF1 dependent apoptosis. The protein expression of CELF1 was up-regulated by OOLE in a dose- and time-dependent manner, but the mRNA expression of CELF1 was unchanged. Analysis by polysomal profiling and nascent protein synthesis revealed that the regulation of CELF1 by OOLE treatment was mediated by directly accelerating its protein translation. CONCLUSION: OOLE-induces apoptosis in Caco-2 cells partially through up-regulation of CELF1.

Inhibition of Autophagic Degradation Process Contributes to Claudin-2 Expression Increase and Epithelial Tight Junction Dysfunction in TNF-α Treated Cell Monolayers.

Tight junction dysfunction plays a vital role in some chronic inflammatory diseases. Pro-inflammatory cytokines, especially tumor necrosis factor alpha (TNF-α), act as important factors in intestinal epithelial tight junction dysfunction during inflammatory conditions. Autophagy has also been shown to be crucial in tight junction function and claudin-2 expression, but whether autophagy has an effect on the change of claudin-2 expression and tight junction function induced by TNF-α is still unknown. To answer this question, we examined the expression of claudin-2 protein, transepithelial electrical resistance (TER), and permeability of cell monolayers, autophagy flux change, and lysosomal pH after TNF-α with or without PP242 treatment. Our study showed that claudin-2 expression, intestinal permeability, microtubule-associated protein 1 light chain 3B II (LC3B-II) and sequestosome 1 (P62) expression largely increased while TER values decreased in TNF-α treated cell monolayers. Further research using 3-methyladenine (3-MA), bafilomycin A1, and ad-mCherry-GFP-LC3B adenovirus demonstrated that LC3B-II increase induced by TNF-α was attributed to the inhibition of autophagic degradation. Moreover, both qualitative and quantitative method confirmed the increase of lysosomal pH, and mammalian target of rapamycin (mTOR) inhibitor PP242 treatment relieved this elevation. Moreover, PP242 treatment also alleviated the change of autophagy flux, TER, and claudin-2 expression induced by TNF-α. Therefore, we conclude that increase of claudin-2 levels and intestinal epithelial tight junction dysfunction are partly caused by the inhibition of autophagic degradation in TNF-α treated cell monolayers.

Contribution of Common Variants in GABRG2, RELN and NRG3 and Interaction Networks to the Risk of Hirschsprung Disease.

BACKGROUND: Hirschsprung disease (HSCR) is a complex and heterogeneous disorder, characterized by a deficit in enteric nervous system. Genome-wide studies implied GABRG2, RELN and NRG3 might be involved in HSCR etiology. Here, we aimed to assess genetic variants in GABRG2, RELN and NRG3 that may confer susceptibility to HSCR and explore genetic interaction networks in HSCR. METHODS: Using a strategy that combined case-control study and gene-gene interaction analysis with the MassArray system, we evaluated 24 polymorphisms within GABRG2, RELN and NRG3 in 104 HSCR cases and 151 normal controls of Han Chinese origin. RESULTS: We observed that seven polymorphisms showed statistically significant differences between HSCR subjects and normal controls. For each of the three genes, the haplotypes which combined eight markers were the most significant. Moreover, we recruited SNPsyn, GO enrichment and MDR analyses to interrogate the interactions among GABRG2, RELN, NRG3 and our previous identified PTCH1 gene. Significant interaction networks were found among GABRG2, RELN, and PTCH1. CONCLUSION: We provide a first indication that common variants of GABRG2, RELN and NRG3 and the GABRG2-RELN-PTCH1 interaction networks might confer altered susceptibility to HSCR in the Han Chinese population, suggesting a potential mechanism underlying HSCR pathogenesis.

Soybean Oil-Based Lipid Emulsion Increases Intestinal Permeability of Lipopolysaccharide in Caco-2 Cells by Downregulation of P-Glycoprotein via ERK-FOXO 3a Pathway.

BACKGROUND AND AIMS: Elevated intestinal permeability of lipopolysaccharide (LPS) is a major complication for patients with parenteral nutrition (PN), but the pathogenesis is poorly understood. Intestinal P-glycoprotein (P-gp) is one of the efflux transporters that contribute to restricting the permeability of lipopolysaccharide via transcellular route. P-gp expression may be regulated by PN ingredients, and thus this study sought to investigate the effect of PN on the expression of P-gp and to elucidate the underlying mechanism in vitro. METHODS: Caco-2 cells were treated with PN ingredients. Changes in P-gp expression and function were determined and the role of ERK-FOXO 3a pathway was studied. Transport studies of FITC-lipopolysaccharide (FITC-LPS) across Caco-2 cell monolayers were also performed. RESULTS: Among PN ingredients, soybean oil-based lipid emulsion (SOLE) exhibited significant inhibitory effect on P-gp expression and function. This regulation was mediated via activation of ERK pathway with subsequent nuclear exclusion of FOXO 3a. Importantly, P-gp participated in antagonizing the permeation of FITC-LPS (apical to basolateral) across Caco-2 cell monolayers. SOLE significantly increased the permeability of FITC-LPS (apical to basolateral), which was associated with impaired P-gp function. CONCLUSIONS: The expression and function of intestinal P-gp is suppressed by SOLE in vitro.