Browsing by Subject "Mucins"

Now showing 1 - 5 of 5
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    Diversity of mucins in labial glands of infants
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Stoeckelhuber, Mechthild; Kesting, Marco R.; Loeffelbein, Denys J.; Schmitz, Christoph; Wolff, Klaus-Dietrich
    Mucins as highly glycosylated proteins comprise multiple functions like protection, homeostasis, immune defense, cell signaling. Various epithelial tissues including glandular structures express different specific mucin types. We investigated labial salivary glands in infants for the occurrence of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, and MUC7 by immunohistochemistry. MUC1 and MUC4 were detected in serous and ductal glandular cells, partially intensified at the apical plasma membrane. MUC3 was found in ductal glandular cells and in myoepithelial cells. MUC5B exhibited a mosaic expression pattern in mucous glandular endpieces. MUC2 and MUC7 were abundant in serous acini. Glandular structures were negative for MUC5AC. A comprehensive study of specific mucins in labial salivary glands of infants was presented for the first time. As a representative of the minor salivary glands, labial glands are, due to their localization, directly exposed to environmental influences. The distribution of a broad spectrum of mucins in infantile labial glands indicates their importance early in human development to sustain oral health.
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    Effects of a probiotic on the morphology and mucin composition of pig intestine
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Desantis, Salvatore; Mastrodonato, Maria; Accogli, Gianluca; Rossi, Giacomo; Crovace, Alberto Maria
    Although the use of probiotics in human and animal medicine is growing, their mode of action remains poorly understood. This study examined the effects of a multi-strain probiotic (SLAB51™) on the morphology and carbohydrate composition of mucins secreted by goblet cells of intestinal crypts in growingfinishing pigs. Sections of duodenum, caecum and colon from pigs fed for 12 weeks with an orally administered control basal diet (No-Pro) or one with a probiotic blend (Pro) were processed for microscopic analysis and stained with (1) haematoxylin-eosin for structural and morphometrical investigation; (2) conventional histochemistry (periodic acid-Schiff, Alcian Blue pH 2.5, high iron diamine staining) for neutral, acidic nonsulphated, and sulphated mucin analysis; and (3) FITClabelled MAA-II and SNA lectins for α2,3- and α2,6- sialomucin identification. Compared with No-Pro samples, Pro samples displayed (1) increased goblet cell numbers in all investigated tract crypts; (2) an increase in acidic non-sulphomucins but a decrease in neutral, sulphated and α2,6-sialomucin-secreting goblet cells in the duodenum; (3) decreased crypt depth, an increase in α2,6-sialomucin secretory goblet cells, and a loss of goblet cell-secreting α2,3-sialomucins, which appeared on the apical surface of crypt fundus epithelial cells in the caecum; and (4) an increase in α2,6-sialomucinproducing goblet cells in the colon. Results suggest that treatment with SLAB51™ induces region-specific changes in the morphology and carbohydrate composition of mucins secreted along intestinal tracts of growing-finishing pigs. These changes could ameliorate the health status of the animals, which displayed higher growth performance and meat quality than controls (Tufarelli et al., 2017).
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    Expression of adhesion molecules and mucins in human and rhesus macaque gastrointestinal epithelial cells
    (F. Hernández y J.F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología., 2011) Zhang, Hong-Yu; Chang, Hong; Fan, Xiao-Na; Zhang, Kui-Dong; Yu, Lu; Cao, Yi
    Epithelial junctions and mucins play key roles in the gastrointestinal mucosal barrier, and their alterations are associated with numerous diseases, including carcinomas. The systematic expression of adhesion molecules and mucins in normal and malignant human gastrointestinal cells was investigated in this study. In normal human gastrointestinal cells, zonula occludens-1 (ZO-1), α-catenin, ß-catenin, γ-catenin and desmoglein-2 (DSG2) were located in the cytoplasmic membranes, whereas symplekin stained in the nuclei. ZO-1, the three catenins, and DSG2 were observed in the gastric and colorectal carcinomas with reduced and heterogeneous expression and with abnormal distribution. Symplekin was detected in the nuclei of tumor cells in most tumors but not observed in some others. The immunohistochemical results for ZO-1 and symplekin on the tissues were consistent with the data for the cultured cells obtained by immunocytochemical staining and Western blot analysis. MUC1 was not stained in the normal gastrointestinal cells without periodate oxidation, but it was strongly labeled in the malignant gastrointestinal cells. MUC2 was detected in the normal and malignant gastrointestinal cells without the periodate treatment. These findings indicate that alterations in the expression of the epithelial junctions and mucins are associated with the malignant transformation of gastrointestinal cells. In addition, the gastrointestinal epithelial cells of rhesus macaques expressed these adhesion molecules and mucins, as did the human cells, suggesting that the rhesus monkey is a suitable experimental animal model for research on adhesion molecules and mucins.
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    Expression of beta-catenin and its mechanism of delocalization in intestinal-type early gastric cancer based on mucin expression
    (Murcia : F. Hernández, 2009) Lee, Soo Han; Kang, Hyun Jeong; Shin, Dong-Hun; Cho, Duk-Yeon; Song, Jin Mi; Kim, G.H.; Song, G.A.; So, Mee Young; Kim, J.Y.; Choi, K.U.; Lee, Chian-Her; Huh, G.Y.; Park, D.Y.; Lee, H.C.
    The biological characteristics of intestinaltype early gastric cancers (ICs) differ based on mucin phenotypes. Beta-catenin delocalization is a predictive marker of aggressive biological behavior (submucosal invasion and lymph node metastasis) of ICs. The presumptive causative genetic alterations leading to delocalization of beta-catenin in ICs are still controversial, and there are only a few reports regarding beta-catenin expression in gastric cancer based on mucin phenotypes. Therefore, in the current study, the expression and mechanisms of delocalization of betacatenin were elucidated on the basis of mucin phenotypes in 109 cases of ICs. There was increased cytoplasmic and nuclear beta-catenin expression (delocalization) in ICs with a predominant intestinal mucin phenotype (ICIP; 46.3% [25/54 cases]) compared to ICs with a predominant gastric mucin phenotype (ICGP; 20% [11/55 cases]). There were no beta-catenin or APC mutations in ICs. APC promoter hypermethylation was present in 49 of 105 (46.7%) cases of ICs. There was a significant relationship between APC promoter hypermethylation and betacatenin delocalization in ICs, especially in ICIPs. There was no relationship between beta-catenin delocalization and APC gene loss of heterozygosity in ICs. In conclusion, we showed that beta-catenin delocalization was more evident in ICIPs, and APC promoter hypermethylation might play a role in delocalization of beta-catenin, especially in ICIPs.
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    Gel-forming mucins. Notions from in vitro studies
    (Murcia : F. Hernández, 2007) Perez-Vilar, J.; Mabolo, R.
    Mucus secretions form a protective barrier in the mucosa of the auditory, gastrointestinal, respiratory, and urogenital systems, and the conjunctiva in the eyes. A family of glycoproteins known as gel forming mucins is the major component of the mucus. Gel-forming mucins are among the largest and most complex proteins known. Their polypeptide chains comprise thousands of amino acid residues organized into different domains with diverse post-translational modifications, including O- and N-glycosylation, sulfation, proteolysis, and likely C-mannosylation. Moreover, these glycoproteins form disulfide-linked oligomers/multimers with molecular weights in the millions. Molecular polydispersity in terms of length, carbohydrate content and composition, is an invariable feature of purified mucins. This structural complexity makes it technically very difficult to study mucin biochemical and physical properties. It is not surprising, therefore, that our knowledge on mucin structure, biosynthesis and function still is incomplete. During the last decade, the use of recombinant mucins has allowed researchers to study the biochemical properties of protein domains, peptide motifs and amino acid residues common to all gel-forming mucins, and to propose specific roles for them. We review here the relative impact that these in vitro studies have had for our current understanding of two of the most important features of these macromolecules: formation of disulfide linked oligomers and mucin intragranular packaging.