http://experimentationlab.berkeley.edu/sites/default/files/AFMImages/butt_AFM.pdf

Force measurements with the atomic force microscope: Technique, interpretation and applications

Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.

Gut Microbiota in Health and Disease

Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences

https://gut.bmj.com/content/gutjnl/45/suppl_2/II1.full.pdf

The functional gastrointestinal disorders and the Rome III process.

Mucins — large extracellular proteins that are heavily glycosylated with complex oligosaccharides — establish a selective molecular barrier at the epithelial surface and engage in morphogenetic signal transduction. Alterations in mucin expression or glycosylation accompany the development of cancer and influence cellular growth, differentiation, transformation, adhesion, invasion and immune surveillance. Mucins are used as diagnostic markers in cancer, and are under investigation as therapeutic targets for cancer.

Mucins in cancer: Protection and control of the cell surface

BACKGROUND AND AIMS—Trefoil factor family (TFF) peptides and the chromosome 11p15.5 mucin glycoproteins are expressed and secreted in a site specific fashion along the length of the gastrointestinal tract. Evidence for coexpression of mucins and trefoil peptides has been suggested in numerous gastrointestinal mucosal pathologies. The ulcer associated cell lineage (UACL) occurs at sites of chronic ulceration in Crohn's disease, expresses all three trefoil peptides, and is implicated in mucosal restitution. We tested the hypothesis that individual trefoil peptides are uniquely localised with specific mucins in the UACL and normal gastrointestinal epithelia.
METHODS—Expression of mucin genes in the UACL from small bowel tissue of patients with Crohn's disease was detected by in situ hybridisation, and localisation of the products by immunohistochemistry. Colocalisation of mucins and trefoil peptides was demonstrated by immunofluorescent colabelling in UACL and normal gastrointestinal epithelia.
RESULTS—MUC5AC and TFF1 were colocalised in distal ductular and surface elements of the UACL and in foveolar cells of the stomach, whereas MUC6 and TFF2 were colocalised to acinar and proximal ductular structures in the UACL, in the fundus and deep antral glands of the stomach, and in Brunner's glands of the duodenum. MUC5B was found sporadically throughout the UACL and gastric body. MUC2 was absent from the UACL, Brunner's glands, and stomach. MUC2 and TFF3 were colocalised throughout the large and small bowel mucosa.
CONCLUSIONS—The UACL has a unique profile of mucin gene expression. Coordinated localisation of trefoil peptides and mucins in UACL and normal gastrointestinal epithelia suggests they may assist each others' functions in protection and repair of gastrointestinal mucosa.


Keywords: mucins; trefoil peptides; Crohn's disease; ulcer associated cell lineage; repair

https://gut.bmj.com/content/gutjnl/47/6/792.full.pdf

Coordinated localisation of mucins and trefoil peptides in the ulcer associated cell lineage and the gastrointestinal mucosa

Background: Mucinases and sialidases contribute to the process of invasion and colonisation in many conditions and infections of the female reproductive tract by degrading the protective cervical mucus. The role of hydrolytic enzymes in the pathogenesis of sexually transmitted diseases and their eVect on cervical mucus are discussed in this review. Methods: Articles were searched for using the keywords “sialidase,” “mucinase,” “protease,” and “sexually transmitted infections.” As well as review and other articles held by our group, searches were conducted using PubMed, Grateful Med, and the University of Bath search engine, BIDS. Results: Numerous publications were found describing the production of hydrolytic enzymes in sexually transmitted diseases. Because the number of publications exceeded the restrictions imposed on the size of the review, the authors selected and discussed those which they considered of the most relevance to sexually transmitted infections. (Sex Transm Inf 2001;77:402‐408)

https://sti.bmj.com/content/sextrans/77/6/402.full.pdf

Mucinases and sialidases: their role in the pathogenesis of sexually transmitted infections in the female genital tract

Lactobacilli, principally the strains that are hydrogen peroxide (H2O2) producing, may have a protective effect against vaginal colonization by pathogenic species such as those that cause bacterial vaginosis. Previous reports have also suggested that H2O2-producing lactobacilli in the vagina may protect pregnant women against ascending infection of the chorioamniotic membranes and uterine cavity. We report the identification and H2O2 production of lactobacilli isolated from vaginal swabs collected at 20 weeks9 gestation from a population of pregnant women at high risk of preterm birth. We also report the correlation between identification and H2O2 production in relation to the outcomes of chorioamnionitis and preterm birth. Lactobacilli were identified by partial 16S rRNA gene sequencing. H2O2 production by isolates was determined by a semiquantitative method. The most commonly isolated species were L. crispatus, L. gasseri, L. vaginalis and L. jensenii. Amounts of H2O2 produced by lactobacilli varied widely. The presence of lactobacilli producing high levels of H2O2 in the vagina of this population of pregnant women was associated with a reduced risk of bacterial vaginosis at 20 weeks9 gestation and subsequent chorioamnionitis. L. jensenii and L. vaginalis produced the highest levels of H2O2. We postulate that H2O2-producing lactobacilli are able to reduce the incidence of ascending infections of the uterus and the subsequent production of proinflammatory molecules which are important in the pathogenesis of chorioamnionitis and preterm birth.

Identification and H2O2 Production of Vaginal Lactobacilli from Pregnant Women at High Risk of Preterm Birth and Relation with Outcome

A human colonic adenoma cell line PC/AA derived from a familial polyposis coli patient was passaged in culture to form an intermediate premalignant clonogenic variant AA/C1 and, upon treatment with differentiating and carcinogenic agents, a cell line AA/C1/SB10 which is tumourigenic in nude mice. These three mucin-secreting cell lines have been used as a model to study the changes in O-glycan biosynthesis during the progression to cancer. Several glycosyltransferases involved in the synthesis, elongation and termination of the common O-glycan core structures were found to decrease in the progression sequence towards adenocarcinoma. Higher activity of a number of enzymes was seen in the intermediate cell line. O-glycan biosynthesis in the original PC/AA cell line was closest to the normal human colonic phenotype, since all four common mucin O-glycan cores and their extended structures could be synthesized; core 3 beta 3-GlcNAc-transferase and alpha 6-sialytransferase acting on GalNAc-mucin were still detectable and core 2 beta 6-GlcNAc-transferase activity was accompanied by core 4 and I beta 6-GlcNAc-transferase activities. During progression towards adenocarcinoma, the expression of alpha 6-sialyltransferase, core 3 beta 3-GlcNAc-transferase, core 4 and I beta 6-GlcNAc-transferases were turned off. Using monoclonal antibodies, Tn antigen, sialyl-Tn antigen, O-acetyl-sialomucin and sialyl-Lea determinants were not detected in secreted or cellular mucin isolated from any of the cell lines. The exposure of MUC1 epitopes was seen in the malignant line, whereas sialyl-Lex determinants were found only in the premalignant PC/AA line. Sulfotransferase activities using core 1 substrate, Gal beta 1-3GalNAc alpha-benzyl, were high in PC/AA cells and progressively decreased upon development to adenocarcinoma, and this decrease correlated with mucin sulfation. In summary, the synthesis of less abundant, sialylated, fucosylated and extended, unbranched core 1 structures should be facilitated in the malignant cells. This is the first report of glycosyltransferase changes in human premalignant cells developing to tumourigenic cells. The data demonstrate that these cell lines are an excellent model to study the changes and regulation of mucin oligosaccharide biosynthesis during progression to cancer.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1994.tb18880.x

O‐glycan biosynthesis in human colorectal adenoma cells during progression to cancer

BACKGROUND AND AIMS—Mucin genes are expressed in a site specific manner throughout the gastrointestinal tract. Little is known about the expression pattern in the oesophagus. In this study we have investigated MUC gene expression in both the normal oesophagus and specialised intestinal metaplasia (Barrett's oesophagus).
PATIENTS—Archived paraffin embedded material from eight specimens of normal oesophagus, 18 Barrett's oesophagus, eight gastric metaplasia, six high grade dysplasia, and six cases of adenocarcinoma were examined for expression of the mucin genes MUC1-6.
METHODS—Mucin mRNA was detected by in situ hybridisation using [35S] dATP labelled oligonucleotide probes. Mucin core protein was detected by immunohistochemistry.
RESULTS—Normal oesophagus expressed MUC5B in the submucosal glands and MUC1 and MUC4 in the stratified squamous epithelium. Barrett's oesophagus strongly expressed MUC5AC and MUC3 in the superficial columnar epithelium, MUC2 in the goblet cells, and MUC6 in the glands. In high grade dysplasia and adenocarcinoma there was downregulation of MUC2, MUC3, MUC5AC, and MUC6, but upregulation of MUC1 and MUC4 in half of the specimens examined.
CONCLUSIONS—Normal oesophagus and Barrett's oesophagus have a novel pattern of mucin gene expression. Barrett's oesophagus expressed the mucins associated with normal gastric epithelium and normal intestinal epithelium. While most mucin genes were downregulated in severely dysplastic and neoplastic tissues, there was upregulation of the membrane bound mucins MUC1 and MUC4. This may prove useful in detecting early signs of progression to adenocarcinoma of the oesophagus.


Keywords: mucins; mucin gene expression; Barrett's oesophagus

https://gut.bmj.com/content/gutjnl/47/6/753.full.pdf

Anthony P. Corfield

Papers

Coordinated localisation of mucins and trefoil peptides in the ulcer associated cell lineage and the gastrointestinal mucosa

Mucinases and sialidases: their role in the pathogenesis of sexually transmitted infections in the female genital tract

Identification and H2O2 Production of Vaginal Lactobacilli from Pregnant Women at High Risk of Preterm Birth and Relation with Outcome

O‐glycan biosynthesis in human colorectal adenoma cells during progression to cancer

Mucin gene expression in Barrett's oesophagus: an in situ hybridisation and immunohistochemical study