Necrotizing enterocolitis (NEC) is an intestinal inflammatory and necrotic disease seen in premature infants, and remains the leading cause of death resulted from gastrointestinal diseases in premature infants. The specific pathogenesis of NEC is still unclear. In recent years, a lot of studies have reported that Toll-like receptor 4 (TLR4) plays a key role in the pathogenesis of NEC. TLR4, which is abundantly expressed in intestinal epithelial cells of premature infants, binds to bacterial lipopolysaccharide (LPS) to activate downstream signaling pathways, leading to disruption of intestinal epithelial integrity and bacterial translocation, resulting in intestinal ischemic necrosis and inflammatory responses, which may rapidly progress to severe sepsis, multiple organ dysfunction, and death. This paper reviews the mechanism of TLR4-related signaling pathways in intestinal epithelial injury and inflammatory responses in newborns with NEC, providing a reference to study new therapeutic targets for NEC.
Enterocolitis, Necrotizing/pathology* ; Toll-Like Receptor 4/metabolism* ; Humans ; Infant, Newborn ; Signal Transduction ; Inflammation/metabolism* ; Animals ; Intestines/immunology* ; Intestinal Mucosa/pathology* ; Infant, Premature

OBJECTIVE: To elucidate the effect of Huanglian-Renshen-Decoction (HRD) on ameliorating type 2 diabetes mellitus by maintaining islet β -cell identity through regulating paracrine and endocrine glucagon-like peptide-1 (GLP-1)/GLP-1 receptor (GLP-1R) in both islet and intestine. METHODS: The db/db mice were divided into the model (distilled water), low-dose HRD (LHRD, 3 g/kg), high-dose HRD (HHRD, 6 g/kg), and liraglutide (400 µ g/kg) groups using a random number table, 8 mice in each group. The db/m mice were used as the control group (n=8, distilled water). The entire treatment of mice lasted for 6 weeks. Blood insulin, glucose, and GLP-1 levels were quantified using enzyme-linked immunosorbent assay kits. The proliferation and apoptosis factors of islet cells were determined by immunohistochemistry (IHC) and immunofluorescence (IF) staining. Then, GLP-1, GLP-1R, prohormone convertase 1/3 (PC1/3), PC2, v-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MafA), and pancreatic and duodenal homeobox 1 (PDX1) were detected by Western blot, IHC, IF, and real-time quantitative polymerase chain reaction, respectively. RESULTS: HRD reduced the weight and blood glucose of the db/db mice, and improved insulin sensitivity at the same time (P<0.05 or P<0.01). HRD also promoted mice to secrete more insulin and less glucagon (P<0.05 or P<0.01). Moreover, it also increased the number of islet β cell and decreased islet α cell mass (P<0.01). After HRD treatment, the levels of GLP-1, GLP-1R, PC1/3, PC2, MafA, and PDX1 in the pancreas and intestine significantly increased (P<0.05 or P<0.01). CONCLUSION HRD can maintain the normal function and identity of islet β cell, and the underlying mechanism is related to promoting the paracrine and endocrine activation of GLP-1 in pancreas and intestine.
Animals ; Glucagon-Like Peptide 1/metabolism* ; Diabetes Mellitus, Type 2/metabolism* ; Glucagon-Like Peptide-1 Receptor/metabolism* ; Insulin-Secreting Cells/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Male ; Blood Glucose/metabolism* ; Insulin/blood* ; Mice ; Intestinal Mucosa/pathology* ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Islets of Langerhans/pathology*

Scavenger receptor class B, member 2 (SCARB2) is linked to Gaucher disease and Parkinson's disease. Deficiency in the SCARB2 gene causes progressive myoclonus epilepsy (PME), a rare group of inherited neurodegenerative diseases characterized by myoclonus. We found that Scarb2 deficiency in mice leads to age-dependent dietary lipid malabsorption, accompanied with vitamin E deficiency. Our investigation revealed that Scarb2 deficiency is associated with gut dysbiosis and an altered bile acid pool, leading to hyperactivation of FXR in intestine. Hyperactivation of FXR impairs epithelium renewal and lipid absorption. Patients with SCARB2 mutations have a severe reduction in their vitamin E levels and cannot absorb dietary vitamin E. Finally, inhibiting FXR or supplementing vitamin E ameliorates the neuromotor impairment and neuropathy in Scarb2 knockout mice. These data indicate that gastrointestinal dysfunction is associated with SCARB2 deficiency-related neurodegeneration, and SCARB2-associated neurodegeneration can be improved by addressing the nutrition deficits and gastrointestinal issues.
Animals ; Mice ; Dysbiosis/metabolism* ; Mice, Knockout ; Humans ; Lysosomal Membrane Proteins/genetics* ; Receptors, Scavenger/genetics* ; Gastrointestinal Microbiome ; Myoclonic Epilepsies, Progressive/genetics* ; Vitamin E Deficiency/complications* ; Neurodegenerative Diseases/genetics* ; Bile Acids and Salts/metabolism* ; Male ; Lipid Metabolism ; Intestinal Mucosa/pathology*

The pathogenesis of inflammatory bowel disease (IBD) is not fully elucidated. However, it has been considered that inflammatory macrophages may be involved in the imbalance of the intestinal mucosal immunity to regulate several signaling pathways, leading to IBD progression. The ratio of M1 to M2 subtypes of activated macrophages tends to increase in the inflamed intestinal section. There are challenges in the diagnosis and treatment of IBD, such as unsatisfactory specificity of imaging findings, low drug accumulation in the intestinal lesions, unstable therapeutic efficacy, and drug-related systemic toxicity. Recently developed nanoparticles may provide a new approach for the diagnosis and treatment of IBD. Nanoparticles targeted to macrophages can be used as contrast agents to improve the imaging quality or used as a drug delivery vector to increase the therapeutic efficiency of IBD. This article reviews the research progress on macrophage-targeting nanoparticles for the diagnosis and treatment of IBD to provide a reference for further research and clinical application.
Humans ; Inflammatory Bowel Diseases/therapy* ; Intestines ; Macrophages/metabolism* ; Intestinal Mucosa/pathology* ; Nanoparticles

Houttuynia cordata polysaccharide (HCP) is extracted from Houttuynia cordata, a key traditional Chinese medicine. The study was to investigate the effects of HCP on intestinal barrier and microbiota in H1N1 virus infected mice. Mice were infected with H1N1 virus and orally administrated HCP at a dosage of 40 mg(kg(d. H1N1 infection caused pulmonary and intestinal injury and gut microbiota imbalance. HCP significantly suppressed the expression of hypoxia inducible factor-1α and decreased mucosubstances in goblet cells, but restored the level of zonula occludens-1 in intestine. HCP also reversed the composition change of intestinal microbiota caused by H1N1 infection, with significantly reduced relative abundances of Vibrio and Bacillus, the pathogenic bacterial genera. Furthermore, HCP rebalanced the gut microbiota and restored the intestinal homeostasis to some degree. The inhibition of inflammation was associated with the reduced level of Toll-like receptors and interleukin-1β in intestine, as well as the increased production of interleukin-10. Oral administration of HCP alleviated lung injury and intestinal dysfunction caused by H1N1 infection. HCP may gain systemic treatment by local acting on intestine and microbiota. This study proved the high-value application of HCP.
Animals ; Cytokines ; metabolism ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; therapeutic use ; Gastrointestinal Microbiome ; drug effects ; Houttuynia ; chemistry ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Inflammation ; drug therapy ; pathology ; Influenza A Virus, H1N1 Subtype ; pathogenicity ; Intestinal Mucosa ; drug effects ; metabolism ; microbiology ; pathology ; Lung ; drug effects ; metabolism ; pathology ; Male ; Mice, Inbred BALB C ; Orthomyxoviridae Infections ; drug therapy ; pathology ; physiopathology ; Plant Extracts ; chemistry ; Polysaccharides ; chemistry ; pharmacology ; therapeutic use ; Toll-Like Receptors ; metabolism ; Zonula Occludens-1 Protein ; metabolism

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most common functional intestinal diseases, but its pathogenesis is still unknown. The present study aimed to screen the differentially expressed proteins in the mucosa of colon between IBS with diarrhea (IBS-D) patients and the healthy controls. METHODS: Forty-two IBS-D patients meeting the Rome III diagnostic criteria and 40 control subjects from July 2007 to June 2009 in Chinese PLA General Hospital were enrolled in the present study. We examined the protein expression profiles in mucosa of colon corresponding to IBS-D patients (n = 5) and controls (n = 5) using 2-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). Secondly, Western blot and immunohistochemical analysis were carried out to validate the screened proteins in 27 IBS-D patients and 27 controls. Thirdly, high-performance liquid chromatography (HPLC) was further carried out to determine ATP concentration in the mucosa of colon between 10 IBS-D patients and 8 controls. Comparisons between 2 groups were performed by Student's t-test or Mann-Whitney U-test. RESULTS: Twelve differentially expressed proteins were screened out. The α-enolase (ENOA) in the sigmoid colon (0.917 ± 0.007 vs. 1.310 ± 0.100, t = 2.643, P = 0.017) and caecum (0.765 ± 0.060 vs. 1.212 ± 0.122, t = 2.225, P = 0.023), Isobutyryl-CoA dehydrogenase (ACAD8) in the sigmoid colon (1.127 ± 0.201 vs. 1.497 ± 0.392, t = 7.093, P = 0.008) of the IBS-D group were significantly lower while acetyl-CoA acetyltransferase (CT) in the caecum (2.453 ± 0.422 vs. 0.931 ± 0.652, t = 8.363, P = 0.015) and ATP synthase subunit d (ATP5H) in the sigmoid (0.843 ± 0.042 vs. 0.631 ± 0.042, t = 8.613,P = 0.007) of the IBS-D group was significantly higher, compared with the controls. The ATP concentration in the mucosa of the sigmoid colon in IBS-D group was significantly lower than that of control group (0.470 [0.180, 1.360] vs. 5.350 [2.230, 7.900], U = 55, P < 0.001). CONCLUSIONS Many proteins related to energy metabolism presented differential expression patterns in the mucosa of colon of the IBS-D patients. The abnormalities in energy metabolism may be involved in the pathogenesis of IBS which deserves more studies to elucidate.
Adenosine Triphosphate ; metabolism ; Adult ; Blotting, Western ; Colon ; metabolism ; pathology ; Diarrhea ; enzymology ; metabolism ; pathology ; Electrophoresis, Gel, Two-Dimensional ; Energy Metabolism ; genetics ; physiology ; Female ; Humans ; Immunohistochemistry ; Intestinal Mucosa ; enzymology ; metabolism ; pathology ; Irritable Bowel Syndrome ; enzymology ; metabolism ; pathology ; Male ; Mass Spectrometry ; Middle Aged ; Proteome ; metabolism

PURPOSE: Early application of protease inhibitors through the intestinal lumen could increase survival following experimental shock by blocking the pancreatic digestive enzymes. Hence, it was hypothesized that two-route injection (intraintestinal + intravenous) of ulinastatin (UTI), a broad-spectrum protease inhibitor, could better alleviate intestinal injury than single-route injection (either intravenous or intraintestinal). METHODS: A sepsis model induced by lipopolysaccharide on rats was established. The rats were randomly divided into five groups: sham, sepsis, UTI intravenous injection (Uiv), UTI intraintestinal injection (Uii), and UTI intraintestinal + intravenous injection (Uii + Uiv) groups. The mucosal barrier function, enzyme-blocking effect, levels of systemic inflammatory cytokines, and 5-day survival rate were compared among groups. The small intestinal villus height (VH), crypt depth (CD), and two components of mucosal barrier (E-cadherin and mucin-2) were measured to evaluate the mucosal barrier function. The levels of trypsin and neutrophil elastase (NE) in the intestine, serum, and vital organs were measured to determine the enzyme-blocking effect. RESULTS: Compared with the single-route injection group (Uiv or Uii), the two-route injection (Uii + Uiv) group displayed: (1) significantly higher levels of VH, VH/CD, E-cadherin, and mucin-2; (2) decreased trypsin and NE levels in intestine, plasma, and vital organs; (3) reduced systemic inflammatory cytokine levels; and (4) improved survival of septic rats. CONCLUSION Two-route UTI injection was superior to single-route injection in terms of alleviating intestinal injury, which might be explained by extensive blockade of proteases through different ways.
Animals ; Cadherins ; metabolism ; Cytokines ; metabolism ; Disease Models, Animal ; Glycoproteins ; administration & dosage ; pharmacology ; Inflammation Mediators ; metabolism ; Injections, Intralesional ; Injections, Intravenous ; Intestinal Diseases ; drug therapy ; etiology ; metabolism ; Intestinal Mucosa ; metabolism ; pathology ; Intestines ; Leukocyte Elastase ; metabolism ; Male ; Mucin-2 ; metabolism ; Rats, Wistar ; Sepsis ; complications ; Trypsin ; metabolism ; Trypsin Inhibitors ; administration & dosage ; pharmacology

OBJECTIVETo investigate the effect of respiratory syncytial virus (RSV)-related pulmonary infection on endogenous metabolites in large intestinal mucosa in BALB/c mice using metabolomics technology based on gas chromatography-mass spectrometry (GC-MS).

METHODSMice were randomly divided into a control group and a RSV pneumonia model group (n=16 each). The mouse model of RSV pneumonia was established using intranasal RSV infection (100×TCID, 50 μL/mouse, once a day). After 7 days of intranasal RSV infection, the mice were sacrificed and GC-MS was used to identify endogenous metabolites and measure the changes in their relative content in colon tissue. SMCA-P12.0 software was used to perform principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) for endogenous metabolites in colon tissue. The differentially expressed metabolites in colon tissue were imported into the metabolic pathway platform Metaboanalyst to analyze related metabolic pathways.

RESULTSPCA and OPLS-DA showed significant differences between the control and RSV pneumonia model groups. A total of 32 metabolites were identified in the colon tissue of the mice with RSV pneumonia. The RSV pneumonia model group had significant increases in the content of leucine, isoleucine, glycine, alanine, arachidonic acid, and lactic acid, which were related to the valine, leucine, isoleucine, arachidonic acid, and pyruvic acid metabolic pathways.

CONCLUSIONSRSV pneumonia might cause metabolic disorders in the large intestinal tissue in mice.

Amino Acids, Branched-Chain ; metabolism ; Animals ; Female ; Gas Chromatography-Mass Spectrometry ; Intestinal Mucosa ; metabolism ; Intestine, Large ; metabolism ; pathology ; Lung ; pathology ; Mice ; Mice, Inbred BALB C ; Pneumonia, Viral ; metabolism ; Respiratory Syncytial Virus Infections ; metabolism

To observe the effect of vasoactive intestinal peptide (VIP) on the metabolism of intestinal fluid and cyclic AMP protein kinase A signaling pathway (cAMP-PKA) and water channel protein 3 (AQP3) in rats with constipation, and to explore the mechanism of VIP in the treatment of constipation.
 Methods: A total of 45 healthy adult rats were randomly divided into a control group, a model group, a model +VIP group. After 4 weeks of VIP treatment, the first black stool time were examined with the ink gastric method; the water content in feces was calculated; the morphological changes in colonic tissues were observed by HE staining. The expression of VIP and AQP3 protein levels in colon tissues were detected by Western blot; and the cAMP, PKA, AQP3 mRNA expression levels were detected by quantitative real time polymerase chain reaction (qPCR). 
 Results: Compared with the control group, the first black stool time was prolonged, the water content of fecal decreased significantly (both P<0.01); part of the colon mucosa epithelial cells were destructed; the goblet cell volume decreased and quantity was reduced; the contents of AQP3 and VIP in colon tissues were significantly decreased, and the cAMP, PKA and AQP3 mRNA levels were decreased in the model group (all P<0.05). Compared with the model group, the first black stool time in the model +VIP group was shortened, the fecal water content increased significantly (both P<0.05); the mucosal epithelium integrity improved, the number of goblet cells increased; the content of AQP3 and VIP in colon tissues was increased, and the cAMP, PKA, and AQP3 mRNA levels were elevated (all P<0.05).
 Conclusion: Intravenous injection of VIP can regulate intestinal fluid metabolism and improve the symptoms of constipation in rats, which might be related to the regulation of VIP-cAMP-PKA-AQP3 signaling pathway.
Animals ; Aquaporin 3 ; physiology ; Aquaporins ; Blotting, Western ; Colon ; chemistry ; pathology ; Constipation ; physiopathology ; therapy ; Cyclic AMP ; physiology ; Defecation ; Epithelial Cells ; pathology ; Feces ; chemistry ; Goblet Cells ; pathology ; Intestinal Mucosa ; metabolism ; pathology ; RNA, Messenger ; Rats ; Signal Transduction ; Vasoactive Intestinal Peptide ; administration & dosage ; physiology ; therapeutic use

OBJECTIVETo study the effect of hypoxia on cofilin activation in intestinal epithelial cells and its relation with distribution of tight junction protein zonula occludens 1 (ZO-1).

METHODSThe human intestinal epithelial cell line Caco-2 was used to reproduce monolayer cells. The monolayer-cell specimens were divided into control group (no treatment), hypoxic group ( exposed to hypoxia), and normoxic group (exposed to normoxia) according to the random number table. Western blotting was used to detect the protein expressions of cofilin and phosphorylatedl cofilin (p-cofilin) of cells in normoxic group and hypoxic group exposed to normoxia or hypoxia for 1, 2, 6, 12, and 24 h and control group, with 9 samples in control group and 9 samples at each time point in the other two groups. The other monolayer-cell specimens were divided into hypoxic group (exposed to hypoxia) and control group (no treatment) according to the random number table. Cells in hypoxic group exposed to hypoxia for 1, 2, 6, 12, and 24 h and control group were obtained. Morphology and distribution of F-actin was observd with laser scanning confocal microscopy, the ratio of F-actin to G-actin was determined by fluorescence method, and distribution of ZO-l and cellular morphology were observed with laser scanning confocal microscopy. The sample number of last 3 experiments was respectively 3, 6, and 3 in both hypoxic group (at each time point) and control group. Data were processed with paired ttest, analysis of variance of repeated measurement, and LSD-t test.

RESULTSThe protein expressions of cofilin and p-cofilin of cells between normoxic group exposed to normoxia for 1 to 24 h and control group showed no significant changes (with values from -0.385 to 1.701, t(p-cofilin)values from 0. 040 to 1.538, P values above 0.05). There were no obvious differences in protein expressions of en filmn of cells between hypoxic group exposed to hypoxia for 1 to 24 h and control group ( with values from 1.032 to 2.390, P values above 0.05). Compared with that in control group, the protein expressions of p-cofilin of cells were greatly reduced in hypoxic group exposed to hypoxia for 1 to 24 h (with values from 4.563 to 22.678, P values below 0.01), especially exposed to hypoxia for 24 h. The protein expressions of cofilin of cells between normoxic group and hypoxic group at each time point were close ( with t values from -0.904 to 1.433, P values above 0.05). In hypoxic group, the protein expressions of p-cofilin of cells exposed to hypoxia for 1, 2, 6, 12, and 24 h were 0.87 +/- 08, 0.780 .05, 0.89 +/- 0.07, 0.68+0. 07, and 0.57 +/- 0.06, respectively, significantly lower than those in normoxic group (0.90 +/- 0.07, 0.97 +/- 0.06, 1.00 +/- 0.06, 1.00 +/- 0.05, and 0.99 +/- 0.05, with t values from 3.193 to 16.434, P values below 0.01). In control group, F-actin in the cytoplasm was abundant, most of it was in bunches. The trend of F-actin was disorderly in hypoxic group from being exposed to hypoxia for 1 h, shortened in length or even dissipated. The ratios of F-actin to G-actin of cells in hypoxic group exposed to hypoxia for 12 and 24 h (0.89 +/- 0.12 and 0.84 +/- 0.19) were obviously decreased as compared with that in control group (1. 00, with t values respectively 3. 622 and 3. 577, P values below 0.01). There were no obvious differences in the ratios of F-actin to G-actin of cells between hypoxic group exposed to hypoxia for 1, 2, and 6 h and control group ( with values from 0.447 to 1.526, P values above 0.05). In control group, cells were compact in arrangement, and ZO-1 was distributed continuously along the cytomnembrane. From being exposed to hypoxia for 2 h, cells became irregular in shape in hypoxic group. ZO-1 was distributed in discontinuous fashion along the cytomembrane with breakage in hypoxic group exposed to hypoxia for 24 h.

CONCLUSIONSHypoxia may cause the disorder of dynamic balance between F-actin and G-actin by inducing cofilin activation, which in turn leads to the changes in distribution of tight junction protein ZO-1 in intestinal epithelial cells.

Actin Depolymerizing Factors ; Actins ; Blotting, Western ; Caco-2 Cells ; drug effects ; physiology ; Epithelial Cells ; cytology ; drug effects ; Humans ; Hypoxia ; metabolism ; Intestinal Mucosa ; drug effects ; metabolism ; pathology ; Intestines ; Oxygen ; pharmacology ; Tight Junctions ; drug effects ; metabolism ; Zonula Occludens-1 Protein ; metabolism