Fucosylated TLR4 mediates communication between mutualist fucotrophic microbiota and mammalian gut mucosa.

Objective: The glycans on the mucosa of suckling mice are predominantly sialylated; upon weaning, fucosylated glycans preponderate. This manifestation of mutualism between fucotrophic bacteria and the mature host utilizes a sentinel receptor in the intestinal mucosa; this receptor was isolated to distinguish its structural and functional features.

Design: Provisional identification of the sentinel gut receptor as fuc-TLR4 was through colonization of germ-free mutant mice.

The Human Milk Oligosaccharide 2'-Fucosyllactose Quenches Campylobacter jejuni-Induced Inflammation in Human Epithelial Cells HEp-2 and HT-29 and in Mouse Intestinal Mucosa.

Background: Campylobacter jejuni causes diarrhea worldwide; young children are most susceptible. Binding of virulent C. jejuni to the intestinal mucosa is inhibited ex vivo by α-fucosylated carbohydrate moieties, including human milk oligosaccharides (HMOSs).

Human Milk Oligosaccharides and Synthetic Galactosyloligosaccharides Contain 3'-, 4-, and 6'-Galactosyllactose and Attenuate Inflammation in Human T84, NCM-460, and H4 Cells and Intestinal Tissue Ex Vivo.

Background: The immature intestinal mucosa responds excessively to inflammatory insult, but human milk protects infants from intestinal inflammation. The ability of galactosyllactoses [galactosyloligosaccharides (GOS)], newly found in human milk oligosaccharides (HMOS), to suppress inflammation was not known.

Objective: The objective was to test whether GOS can directly attenuate inflammation and to explore the components of immune signaling modulated by GOS.

Glucocorticoids and microbiota regulate ontogeny of intestinal fucosyltransferase 2 requisite for gut homeostasis.

At weaning, the intestinal mucosa surface glycans change from predominantly sialylated to fucosylated. Intestinal adaptation from milk to solid food is regulated by intrinsic and extrinsic factors. The contribution by glucocorticoid, an intrinsic factor, and colonization by microbiota, an extrinsic factor, was measured as the induction of α1,2/3-fucosyltransferase and sucrase-isomaltase (SI) activity and gene expression in conventionally raised, germ-free, and bacteria-depleted mice.

Probiotics prevent necrotizing enterocolitis by modulating enterocyte genes that regulate innate immune-mediated inflammation.

Necrotizing enterocolitis (NEC), an extensive intestinal inflammatory disease of premature infants, is caused, in part, by an excessive inflammatory response to initial bacterial colonization due to the immature expression of innate immune response genes. In a randomized placebo-controlled clinical trial, supplementation of very low birth weight infants with probiotics significantly reduced the incidence of NEC. The primary goal of this study was to determine whether secreted products of these two clinically effective probiotic strains, Bifidobacterium infantis and Lactobacillus acidophilus, prevented NEC by accelerating the maturation of intestinal innate immune response genes and whether both strains are required for this effect.

TGF-β2 induces maturation of immature human intestinal epithelial cells and inhibits inflammatory cytokine responses induced via the NF-κB pathway.

Objectives: Breast milk transforming growth factor (TGF)-β2 is associated with healthy immune maturation and reduced risk of immune-mediated disease in infants. We sought to investigate whether conditioning with TGF-β2 may result in a more mature immune responder phenotype in immature human intestinal epithelial cells (IECs).

Methods: Primary human fetal IECs (hFIECs) and the human fetal small intestinal epithelial cell line (H4 cells) were conditioned with breast milk levels of TGF-β2, and an inflammatory response was subsequently induced.

The mechanism of excessive intestinal inflammation in necrotizing enterocolitis: an immature innate immune response.

Necrotizing enterocolitis (NEC) is a devastating neonatal intestinal inflammatory disease, occurring primarily in premature infants, causing significant morbidity and mortality. The pathogenesis of NEC is associated with an excessive inflammatory IL-8 response. In this study, we hypothesized that this excessive inflammatory response is related to an immature expression of innate immune response genes.

Vitamin A supplementation modifies the association between mucosal innate and adaptive immune responses and resolution of enteric pathogen infections.

Background: The efficacy of vitamin A supplementation on diarrheal disease morbidity may reflect the divergent effects that supplementation has on pathogen-specific immune responses and pathogen-specific outcomes.

Objective: We examined how vitamin A supplementation modified associations between gut-cytokine immune responses and the resolution of different diarrheal pathogen infections.

Design: Stools collected from 127 Mexican children who were 5-15 mo old and enrolled in a randomized, placebo-controlled vitamin A supplementation trial were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E.

Breast milk-transforming growth factor-β₂ specifically attenuates IL-1β-induced inflammatory responses in the immature human intestine via an SMAD6- and ERK-dependent mechanism.

Background: Breast milk is known to protect the infant against infectious and immuno-inflammatory diseases, but the mechanisms of this protection are poorly understood.

Objectives: We hypothesized that transforming growth factor-β₂ (TGF-β₂), an immunoregulatory cytokine abundant in breast milk, may have a direct anti-inflammatory effect on immature human intestinal epithelial cells (IECs).

Methods: Human fetal ileal organ culture, primary human fetal IECs, and the human fetal small intestinal epithelial cell line H4 were stimulated with interleukin 1β (IL-1β) with or without TGF-β₂.

Associations between mucosal innate and adaptive immune responses and resolution of diarrheal pathogen infections.

The identification of immune response mechanisms that contribute to the control of diarrheal disease in developing countries remains an important priority. We addressed the role of fecal chemokines and cytokines in the resolution of diarrheal Escherichia coli and Giardia lamblia infections. Stools collected from 127 Mexican children 5 to 15 months of age enrolled in a randomized, double-blind, placebo-controlled, vitamin A supplementation trial were screened for enteropathogenic Escherichia coli (EPEC), enterotoxigenic E.

A mouse model of Clostridium difficile-associated disease.

Background & Aims: Infection with Clostridium difficile causes nosocomial antibiotic-associated diarrhea and colitis. Hamsters historically have been used to investigate disease pathogenesis and treatment, but are not ideal models because of the lack of hamster-specific reagents and genetically modified animals, and because they develop fulminant disease. The aim of this study was to establish a mouse model of antibiotic-induced C.

Neurologic, gastric, and opthalmologic pathologies in a murine model of mucolipidosis type IV.

Mucolipidosis type IV (MLIV) is an autosomal recessive lysosomal storage disorder caused by mutations in the MCOLN1 gene, which encodes the 65-kDa protein mucolipin-1. The most common clinical features of patients with MLIV include severe mental retardation, delayed motor milestones, ophthalmologic abnormalities, constitutive achlorhydria, and elevated plasma gastrin levels. Here, we describe the first murine model for MLIV, which accurately replicates the phenotype of patients with MLIV.

Bacterial symbionts induce a FUT2-dependent fucosylated niche on colonic epithelium via ERK and JNK signaling.

The intestinal epithelium of the adult gut supports a complex, dynamic microbial ecosystem and expresses highly fucosylated glycans on its surface. Uncolonized gut contains little fucosylated glycan. The transition toward adult colonization, such as during recovery from germ-free status or from antibiotic treatment, increased expression of fucosylated epitopes in the colonic epithelium.

Secreted probiotic factors ameliorate enteropathogenic infection in zinc-deficient human Caco-2 and T84 cell lines.

Zinc deficiency enhances infectious diarrhea whereas probiotics may inhibit pathogen enterocyte invasion. The effect of probiotics on zinc-deficient versus normal human intestinal epithelium (Caco-2 and T-84) with regard to invasion and subsequent inflammatory response by Salmonella typhimurium was determined. Cells were infected with pathogens and preincubated with media conditioned by several lactobacilli or Bifidobacterium bifidum 12.

Vitamin A supplementation reduces the monocyte chemoattractant protein-1 intestinal immune response of Mexican children.

The impact of vitamin A supplementation on childhood diarrhea may be determined by the regulatory effect supplementation has on the mucosal immune response in the gut. Previous studies have not addressed the impact of vitamin A supplementation on the production of monocyte chemoattractant protein 1 (MCP-1), an essential chemokine involved in pathogen-specific mucosal immune response. Fecal MCP-1 concentrations, determined by an enzyme-linked immuno absorption assay, were compared among 127 Mexican children 5-15 mo of age randomized to receive a vitamin A supplement (<12 mo of age, 20,000 IU of retinol; > or =12 mo, 45,000 iu) every 2 mo or a placebo as part of a larger vitamin A supplementation trial.

The effect of vitamin A supplementation on the intestinal immune response in Mexican children is modified by pathogen infections and diarrhea.

Vitamin A supplementation has consistently reduced infant mortality and the severity of pathogen-induced diarrhea. The mechanism by which vitamin A modulates the mucosal immune response to produce these effects remains poorly defined. To address this issue, stools collected during the summer months from 127 Mexican children 5-15 mo old enrolled in a larger, randomized, double-blind, placebo-controlled, vitamin A supplementation trial were screened for interleukin (IL)-4, IL-6, interferon-gamma (IFN-gamma), and gastrointestinal pathogens.

Glucocorticoid responsiveness in developing human intestine: possible role in prevention of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a major inflammatory disease of the premature human intestine that can be prevented by glucocorticoids if given prenatally before the 34th wk of gestation. This observation suggests that a finite period of steroid responsiveness exists as has been demonstrated in animal models. Human intestinal xenografts were used to determine whether a glucocorticoid responsive period exists in the developing human intestine.

Regulation of intestinal ontogeny: effect of glucocorticoids and luminal microbes on galactosyltransferase and trehalase induction in mice.

Intestinal maturation can be influenced by intrinsic factors (glucocorticoid hormones) and by extrinsic factors (resident microflora); their relative roles in ontogeny of mouse intestinal trehalase expression, a marker of general gut development, and of beta1,4-galactosyltransferase (beta GT), a marker of glycosyltransferase development, were investigated. In conventional (CONV) mice, beta GT and trehalase gene expression rapidly increased to adult levels by the fourth postnatal week. In germ-free (GF) mice, beta GT expression remained at initial low levels and was rapidly induced on reintroduction of luminal microbes of the adult gut but not of microbes characteristic of the suckling gut.

Energetic and nutritional regulation of the adaptive immune response and trade-offs in ecological immunology.

Ecological Immunology views immunocompetence as a costly process involving trade-off decisions among competing nutrient demands by different life-history traits. This review examines immunocompetence fitness costs in light of recent work on the role the energetic and nutritional status of the host plays in the regulation of the adaptive T-helper lymphocyte response. Three phenotypically distinct T-lymphocyte populations have been identified: the Th1 response, important in protecting against intracellular infections; the Th2 response, important in protecting against noninvasive infections such as helminthes; and the Th3 or Treg population, which downregulates polarized Th1 or Th2 responses.

Normal and glucocorticoid-induced development of the human small intestinal xenograft.

The aim of this study was to determine whether intestinal xenografts could recapitulate human in utero development by using disaccharidases as markers. Twenty-week-old fetal intestine was transplanted into immunocompromised mice and was followed. At 20-wk of gestation, the fetal human intestine was morphologically developed with high sucrase and trehalase but had low lactase activities.

The role of indigenous microflora in the development of murine intestinal fucosyl- and sialyltransferases.

Most enteric bacteria use intestinal brushborder glycoconjugates as their target host cell receptors. It has been postulated that resident microbes regulate specific glycosyltransferases that are responsible for synthesizing brushborder glycoconjugates. To investigate this hypothesis, we measured glycosyltransferase enzyme activities in intestine from different regions of maturing conventional (CONV), germ-free (GF), and ex-germ-free (XGF) mice and compared them to general enzyme markers of gut development, for example, disaccharidases.

Region-specific ontogeny of alpha-2,6-sialyltransferase during normal and cortisone-induced maturation in mouse intestine.

Regional differences in the ontogeny of mouse intestinal alpha-2,6-sialyltransferase activities (alpha-2,6-ST) and the influence of cortisone acetate (CA) on this expression were determined. High ST activity and alpha-2,6-ST mRNA levels were detected in immature small and large intestine, with activity increasing distally from the duodenum. As the mice matured, ST activity (predominantly alpha-2,6-ST) in the small intestine decreased rapidly to adult levels by the fourth postnatal week.