| 1. |
- Davies, Julia, et al.
(författare)
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MUC16 is produced in tracheal surface epithelium and submucosal glands and is present in secretions from normal human airway and cultured bronchial epithelial cells.
- 2007
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Ingår i: International Journal of Biochemistry & Cell Biology. - : Elsevier BV. - 1878-5875 .- 1357-2725. ; 39:10, s. 1943-1954
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Tidskriftsartikel (refereegranskat)abstract
- The gel-forming MUC5AC and MUC5B mucins have been identified as major components of human airway mucus but it is not known whether additional mucin species, possibly with other functions, are also present. MUC16 mucin is a well-known serum marker for ovarian cancer, but the molecule has also been found on the ocular surface and in cervical secretions suggesting that it may play a role on the normal mucosal surface. In this investigation, the LUM16-2 antiserum (raised against a sequence in the N-terminal repeat domain) recognized MUC16 in goblet and submucosal gland mucous cells as well as on the epithelial surface of human tracheal tissue suggesting that the mucin originates from secretory cells. MUC16 mucin was present in ‘normal’ respiratory tract mucus as well as in secretions from normal human bronchial epithelial (NHBE) cells. MUC16 from NHBE cells was a high-molecular-mass, monomeric mucin which gave rise to large glycopeptides after proteolysis. N- and C-terminal fragments of the molecule were separated on gel electrophoresis showing that the MUC16 apoprotein undergoes a cleavage between these domains, possibly in the SEA domain as demonstrated for other transmembrane mucins; MUC1 and MUC3. After metabolic labeling of NHBE cells, most of the secreted monomeric, high-molecular-mass [35S]sulphate-labelled molecules were immunoprecipitated with the OC125 antibody indicating that MUC16 is the major [35S]sulphate-labelled mucin in NHBE cell secretions.
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| 2. |
- Davies, Julia R., et al.
(författare)
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Identification of MUC5B, MUC5AC and small amounts of MUC2 mucins in cystic fibrosis airway secretions
- 1999
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Ingår i: Biochemical Journal. - 0264-6021. ; 344:2, s. 321-330
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the genetic identities of the mucins secreted in cystic fibrosis (CF) airways, sputum was collected from five individuals. Samples were separated into gel and sol phases by high-speed centrifugation and the gel phase was extracted in 6 M guanidinium chloride. The 'insoluble' residue remaining after extraction of the gel phase was brought into solution by reduction/alkylation. Density-gradient centrifugation in CsCl revealed polydisperse distributions of sialic acid-containing mucins in the gel phase, insoluble residue and sol phase fractions and the degree of variation between the different individuals was low. Antibodies recognizing MUC5AC and MUC5B identified these mucins in each of the fractions. MUC2, however, was present only as a component of the insoluble residue from the gel which accounted for less than 4% by mass of the total mucins, MUC5B and MUC5AC from the gel phase were large oligomeric species composed of disulphide-bond linked subunits and MUC5B was present as two populations with different charge densities which are likely to correspond to MUC5B 'glycoforms'. The sol phase contained, in addition to MUC5AC and MUC5B mainly smaller mucins which did not react with the antisera and which were probably degraded. MUC5AC appeared to be enriched in the sol, suggesting that this mucin may be more susceptible to proteolytic degradation than MUC5B. The mucins present in sputum remained broadly similar during acute exacerbation and following antibiotic treatment, although the relative amount of an acidic MUC5B glycoform was decreased during infection.
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| 3. |
- Davies, Julia, et al.
(författare)
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Respiratory tract mucins : structure and expression patterns
- 2002
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Ingår i: Novartis Foundation symposium. - Chichester, UK : John Wiley & Sons, Ltd. - 1528-2511 .- 1935-4657. ; 248, s. 76-93
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Goblet cells produce mainly MUC5AC, but also MUC5B and some MUC2 in apparently ‘irritated’ airways. MUC5B dominates in the submucosal glands although a little MUC5AC and MUC7 are usually present. MUC4 originates from the ciliated cells. After separation into a gel and a sol phase, lysozyme and lactoferrin are enriched in the salivary gel phase suggesting that mucus may act as a matrix for ‘protective’ proteins on the mucosal surface. A salivary MUC5B N-terminal fragment consistent with a cleavage event in the D’ domain was de-tected with antibodies against various N-terminal peptide sequences suggesting that assembly of MUC5B occurs through a mechanism similar to that of the von Willebrand factor. Identification of additional cleavage sites C-terminal to the D’ domain suggests that most of the N-terminal low-glycosylated part of MUC5B may be removed without affecting the oligomeric nature of the mucin. Possibly, the generation of mucins with different macromolecular properties through proteolytic ‘processing’ is one way of adapting the mucus polymer matrix to meet local physiological demands. Monomeric mucins that appear to turn over rapidly in the airway epithelium have been identified using radiolabelled mucin precursors. ‘Shedding’ of such mucins after microbe attachment may prevent colonization of epithelial surfaces.
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| 4. |
- Rydberg, Viktor, et al.
(författare)
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Genetic investigation of Nordic patients with complement-mediated kidney diseases
- 2023
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Ingår i: Frontiers in Immunology. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundComplement activation in atypical hemolytic uremic syndrome (aHUS), C3 glomerulonephropathy (C3G) and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) may be associated with rare genetic variants. Here we describe gene variants in the Swedish and Norwegian populations.MethodsPatients with these diagnoses (N=141) were referred for genetic screening. Sanger or next-generation sequencing were performed to identify genetic variants in 16 genes associated with these conditions. Nonsynonymous genetic variants are described when they have a minor allele frequency of ResultsIn patients with aHUS (n=94, one also had IC-MPGN) 68 different genetic variants or deletions were identified in 60 patients, of which 18 were novel. Thirty-two patients had more than one genetic variant. In patients with C3G (n=40) 29 genetic variants, deletions or duplications were identified in 15 patients, of which 9 were novel. Eight patients had more than one variant. In patients with IC-MPGN (n=7) five genetic variants were identified in five patients. Factor H variants were the most frequent in aHUS and C3 variants in C3G. Seventeen variants occurred in more than one condition.ConclusionGenetic screening of patients with aHUS, C3G and IC-MPGN is of paramount importance for diagnostics and treatment. In this study, we describe genetic assessment of Nordic patients in which 26 novel variants were found.
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| 5. |
- Svitacheva, Naila
(författare)
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Aiway Mucins: experimental models for studies of secretions
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mucins are essential components of the mucosal barrier. The complexity of the airway mucosal barrier is reflected in the lack of specific treatments to block mucin hypersecretion associated with several respiratory diseases such as chronic bronchitis, asthma and cystic fibrosis. Currently, researchers in the mucin field are confronted with a growing number of mucin genes. In order to understand the function and the role of individual members of the mucin family in health and disease adequate experimental models are needed. Using sputum as a model to study mucins secreted into the airways in cystic fibrosis, MUC5AC and MUC5B mucins were identified as the predominant gel-forming species. No major differences were found in the macromolecular properties of the MUC5AC and MUC5B mucins when compared with normal airway secretions. MUC2 was found in small amounts within the ‘insoluble’ extraction residue from the gel. Bovine trachea was established as an in vitro model. A ‘novel’ mucin-like highly radiolabelled component was identified both in organ cultures and primary cell cultures whereas the major mucins identified using chemical methods were not labelled. In the light of this finding, many studies where radiolabelling and the release of radiolabelled molecules have been used as a marker for large oligomeric gel-forming mucins, require re-interpretation. The suitability of mucin-secreting methotrexate-treated HT29 cell line and two subclones thereof as a potential alternative to animal models was investigated. Two major airway mucins MUC5AC and MUC5B were produced as well as some MUC2.
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| 6. |
- Svitacheva, Naila, et al.
(författare)
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Biosynthesis of mucins in bovine trachea : identification of the major radiolabelled species
- 1998
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Ingår i: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 333:2, s. 449-456
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Tidskriftsartikel (refereegranskat)abstract
- Bovine trachea in organ culture secretes mucus containing a 'high-density' (1.46 g/ml) and a 'low-density' (1.37 g/ml) mucin similar to those identified previously in bovine respiratory secretions [Hovenberg, Carlstedt and Davies (1997) Biochem. J. 321, 117-123]. After pulse-labelling, autoradiography showed uptake of [35S]sulphate by both epithelial goblet cells and submucosal glands, while [3H]proline was mainly incorporated into the ciliated surface epithelial cells. After 24 h of radiolabelling, neither the high- nor the low-density mucin in the secreted mucus gel was heavily radiolabelled with the precursors. In contrast, a population of molecules banding at 1.50 g/ml was heavily radiolabelled with [35S]sulphate. This component was smaller than the high-density mucin from the mucus gel and was insensitive to reduction or digestion with chondroitin ABC lyase or heparan sulphate lyase. The molecules yielded two populations of high-Mr glycopeptides upon trypsin digestion, were sensitive to keratanase and endo-beta-galactosidase digestion and contained O-linked glycans. Extracts of the surface epithelium and submucosal tissue after radiolabelling showed that the high- and low-density mucins in the tissue were also poorly radiolabelled. Thus, under these conditions, the radiolabelled precursors were not effectively incorporated into the large oligomeric mucins but into a high-Mr monomeric species. This study suggests that data obtained in investigations where mucins are radiolabelled and studied without further separation into distinct components may rather reflect the turnover of this 'novel' monomeric species than the large oligomeric mucins.
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