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Isabelle Van Seuningen - One of the best experts on this subject based on the ideXlab platform.
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Lepidic predominant adenocarcinoma and invasive mucinous adenocarcinoma of the lung exhibit specific mucin expression in relation with oncogenic drivers
Lung Cancer, 2017Co-Authors: Michaël Duruisseaux, Isabelle Van Seuningen, Martine Antoine, Nathalie Rabbe, Anita Rodenas, Anne Mc Leer-florin, Roger Lacave, Virginie Poulot, Belinda Duchêne, Jacques CadranelAbstract:Objectives: To evaluate MUC1, MUC2, MUC5B, MUC5AC, and MUC6 expression in invasive lepidic predominant adenocarcinoma (LPA) and invasive mucinous adenocarcinoma (IMA) of the lung, and the impact of oncogenic drivers. Materials and methods: MUC1, MUC2, MUC5B, MUC5AC, MUC6, TTF1 and Hnf4α immunohistochemistry was performed on surgical samples from 52 patients with IMA (n = 25) or LPA (n = 27). We searched for EGFR, KRAS, BRAF, and HER2 mutations and ALK, ROS1, and NRG1 rearrangements. Results: MUC1, MUC2, MUC5B, MUC5AC, and MUC6 expression was detected in tumor cells in 77%, 2%, 63%, 36%, and 21% of cases, respectively. MUC1 was significantly more overexpressed in LPA. MUC5B, MUC5AC, and MUC6 were typically detected in goblet cells and overexpressed in IMA. Hnf4α-positive IMA (n = 11) were TTF1-negative and typically did not expressed MUC1 and expressed MUC5AC and MUC6. Hnf4α-negative IMA (n = 14) showed a reverse profile of mucins expression, with MUC1 expression and a lack of MUC5AC and MUC6 expression. EGFR-positive status was significantly associated with LPA, MUC1 expression, and no MUC5B, MUC5AC, or MUC6 expression. KRAS-positive status was significantly associated with IMA and MUC5B and MUC5AC expression. Conclusions: LPA and IMA exhibit specific mucin expression profiles, with MUC1 being associated with LPA, while MUC5B, MUC5AC, and MUC6 were associated with IMA. Hnf4α expression and EGFR and KRAS mutations may play a role in mucin expression profiles of these lung adenocarcinoma subtypes.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor-1 (TTF-1) and GATA-6 transcription factors.
FEBS Journal, 2011Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor‐1 (TTF‐1) and GATA‐6 transcription factors
The FEBS journal, 2010Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.
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signal pathway of 17β estradiol induced MUC5B expression in human airway epithelial cells
American Journal of Respiratory Cell and Molecular Biology, 2009Co-Authors: Hye Joung Choi, Yoo Sam Chung, Hyun Jik Kim, Uk Yeol Moon, Yeon Ho Choi, Isabelle Van Seuningen, Seung Joon Baek, Hogeun Yoon, Jooheon YoonAbstract:MUC5B is a major mucin of the human respiratory tract, and it is not clear how MUC5B expression is regulated in various airway diseases. The goal of this study was to determine the mechanisms by which 17beta-estradiol induces MUC5B gene expression in airway epithelial cells. It was found that E2, a sex hormone, stimulates MUC5B gene overexpression by interaction with estrogen receptor alpha (ERalpha) and by acting through extracellular signal-regulated kinase 1/2 (ERK1/2)-mitogen-activated protein kinase (MAPK). Pretreatment with ER antagonist ICI 182,780 blocked both E2-induced ERK1/2-MAPK activation and MUC5B gene expression. It was also found that the activation of p90 ribosomal S 6 protein kinase 1 (RSK1), cAMP-response element-binding protein (CREB), and cAMP-response element (CRE) (-956 region of the MUC5B promoter)-responsive signaling cascades via ERK1/2 MAPK are crucial aspects of the intracellular mechanisms that mediate MUC5B gene expression. Taken together, these studies give additional insights into the molecular mechanism of hormone-induced MUC5B gene expression and enhance our understanding of abnormal mucin secretion in response to hormonal imbalances.
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Signal Pathway of 17β-Estradiol–Induced MUC5B Expression in Human Airway Epithelial Cells
American journal of respiratory cell and molecular biology, 2008Co-Authors: Hye Joung Choi, Yoo Sam Chung, Hyun Jik Kim, Yeon Ho Choi, Isabelle Van Seuningen, Seung Joon Baek, Hogeun Yoon, Yeol Moon, Jooheon YoonAbstract:MUC5B is a major mucin of the human respiratory tract, and it is not clear how MUC5B expression is regulated in various airway diseases. The goal of this study was to determine the mechanisms by which 17β-estradiol induces MUC5B gene expression in airway epithelial cells. It was found that E2, a sex hormone, stimulates MUC5B gene overexpression by interaction with estrogen receptor α (ERα) and by acting through extracellular signal–regulated kinase 1/2 (ERK1/2)-mitogen-activated protein kinase (MAPK). Pretreatment with ER antagonist ICI 182,780 blocked both E2-induced ERK1/2-MAPK activation and MUC5B gene expression. It was also found that the activation of p90 ribosomal S 6 protein kinase 1 (RSK1), cAMP-response element-binding protein (CREB), and cAMP-response element (CRE) (−956 region of the MUC5B promoter)-responsive signaling cascades via ERK1/2 MAPK are crucial aspects of the intracellular mechanisms that mediate MUC5B gene expression. Taken together, these studies give additional insights into the...
Nicolas Jonckheere - One of the best experts on this subject based on the ideXlab platform.
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Depletion of MUC5B mucin in gastrointestinal cancer cells alters their tumorigenic properties: implication of the Wnt/β-catenin pathway
Biochemical Journal, 2017Co-Authors: Fatima Lahdaoui, Mathieu Messager, Audrey Vincent, Flora Hec, Anne Gandon, Maxime Warlaumont, Florence Renaud, Emmanuelle Leteurtre, Guillaume Piessen, Nicolas JonckheereAbstract:Secreted mucins are large O-glycosylated proteins that participate in the protection/defence of underlying mucosae in normal adults. Alteration of their expression is a hallmark of numerous epithelial cancers and has often been correlated to bad prognosis of the tumour. The secreted mucin MUC5B is overexpressed in certain subtypes of gastric and intestinal cancers, but the consequences of this altered expression on the cancer cell behaviour are not known. To investigate the role of MUC5B in carcinogenesis, its expression was knocked-down in the human gastric cancer cell line KATO-III and in the colonic cancer cell line LS174T by using transient and stable approaches. Consequences of MUC5B knocking-down on cancer cells were studied with respect to in vitro proliferation, migration and invasion, and in vivo on tumour growth using a mouse subcutaneous xenograft model. Western blotting, luciferase assay and qRT-PCR were used to identify proteins and signalling pathways involved. In vitro MUC5B down-regulation leads to a decrease in proliferation, migration and invasion properties in both cell lines. Molecular mechanisms involved the alteration of β-catenin expression, localization and activity and decreased expression of several of its target genes. In vivo xenografts of MUC5B-deficient cells induced a decrease in tumour growth when compared with MUC5B-expressing Mock cells. Altogether, the present study shows that down-regulation of MUC5B profoundly alters proliferation, migration and invasion of human gastrointestinal cancer cells and that these alterations may be, in part, mediated by the Wnt/β-catenin pathway emphasizing the potential of MUC5B as an actor of gastrointestinal carcinogenesis.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor-1 (TTF-1) and GATA-6 transcription factors.
FEBS Journal, 2011Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor‐1 (TTF‐1) and GATA‐6 transcription factors
The FEBS journal, 2010Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.
Jean Luc Desseyn - One of the best experts on this subject based on the ideXlab platform.
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MUC5B is mainly expressed and sialylated in the nasal olfactory epithelium whereas Muc5ac is exclusively expressed and fucosylated in the nasal respiratory epithelium.
Histochemistry and Cell Biology, 2019Co-Authors: Salah-eddine Amini, Frédéric Gottrand, Valérie Gouyer, Céline Portal, Jean Luc DesseynAbstract:The nose is a complex organ that filters and warms breathing airflow. The nasal epithelium is the first barrier between the host and the external environment and is covered by a mucus gel that is poorly documented. Mucins are large, heavily O-glycosylated polymeric molecules secreted in the nose lumen by specialized cells, and they are responsible for the biochemical properties of the mucus gel. The mucus traps particles and clears them, and it also bathes microbiota, host molecules, and receptors that are all essential for odor perception in the olfactory epithelium. We used histology and immunohistochemistry to study the expression of the two main airway polymeric mucins, Muc5ac and MUC5B, in wild-type, green fluorescent protein-reporter MUC5B, and in genetically MUC5B-deficient mice. We report that Muc5ac is produced by goblet cells at the cell surface in the respiratory epithelium but is not expressed in the olfactory epithelium, whereas MUC5B is secreted by Bowman's glands situated in the lamina propria beneath the olfactory epithelium and also by goblet cells in the distal part of the respiratory epithelium. We also observed that MUC5B-deficient mice exhibited depletion of Bowman's glands. Using lectins, we found that terminally O-glycosylated chains of MUC5B were sialylated but not fucosylated, whereas Muc5ac was fucosylated but not sialylated. Specific localization and specific terminal glycosylation of the two mucins suggest different functions of the mucins.
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Transgenic Mouse Reporter to Study MUC5B In Vivo
Annals of the American Thoracic Society, 2018Co-Authors: Jean Luc Desseyn, Frédéric Gottrand, Céline Portal, Valérie GouyerAbstract:Dysregulation of gel-forming mucins is associated with many airway diseases. Better knowledge of the pathophysiological mechanisms linking mucins and respiratory diseases will advance the understanding of their pathogenesis and should provide opportunities to develop new therapeutic compounds for treatment. MUC5B and MUC5AC are the two main gel-forming mucins in the respiratory tract. The organization in domains and the expression profile of mouse MUC5B are very similar to those in humans, which makes the mouse a relevant model for studies of the translational activities of human mucins. To assess the in vivo biological functions of MUC5B, a mouse reporter tagged in frame with the green fluorescent protein marker has been engineered by homologous recombination. The proof of concept that this reporter model may be informative for translational studies was confirmed by the finding that interleukin-13 administration in living mice upregulated MUC5B production.
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In vivo imaging of the MUC5B gel-forming mucin.
Scientific reports, 2017Co-Authors: Céline Portal, Valérie Gouyer, Frédéric Gottrand, Mylene Magnien, Ségolène Plet, Jean Luc DesseynAbstract:Gel-forming mucins are macromolecules produced by goblet cells and responsible for the mucus gel formation. Changes in goblet cell density and in gel-forming mucin production have emerged as sensitive indicators for mucosal diseases. A MUC5B-GFP tagged reporter mouse was used to assess MUC5B production in mouse tissues by immunofluorescence microscopy and fluorescent activity using stereromicroscopy and probe-based confocal laser endomicroscopy. MUC5B production was followed longitudinally by recording the fluorescent activity in vagina and in embryonic lung explants under stimulation by interleukin 13. We show that the GFP is easily visualized in the mouse adult ear, nose, trachea, gallbladder, and cervix. Live MUC5B is also easily monitored in the nasal cavity, trachea and vagina where its production varies during the estrus cycle with a peak at the proestrus phase and in pregnant mice. Explant culture of reporter mouse embryonic whole lung shows that interleukin 13 stimulates MUC5B production. The transgenic MUC5B-GFP mouse is unique and suitable to study the mechanisms that regulate MUC5B production/secretion and mucous cell differentiation by live imaging and can be applied to test drug efficacy in mucosal disease models.
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Assembly of the respiratory Mucin MUC5B a new model for a gel-forming Mucin
The Journal of biological chemistry, 2014Co-Authors: Caroline Ridley, Nikos Kouvatsos, Bertrand Raynal, Marj Howard, Richard F. Collins, Jean Luc Desseyn, Thomas A. Jowitt, Clair Baldock, C. William Davis, Timothy E. HardinghamAbstract:Mucins are essential components in mucus gels that form protective barriers at all epithelial surfaces, but much remains unknown about their assembly, intragranular organization, and post-secretion unfurling to form mucus. MUC5B is a major polymeric mucin expressed by respiratory epithelia, and we investigated the molecular mechanisms involved during its assembly. Studies of intact polymeric MUC5B revealed a single high affinity calcium-binding site, distinct from multiple low affinity sites on each MUC5B monomer. Self-diffusion studies with intact MUC5B showed that calcium binding at the protein site catalyzed reversible cross-links between MUC5B chains to form networks. The site of cross-linking was identified in the MUC5B D3-domain as it was specifically blocked by D3 peptide antibodies. Biophysical analysis and single particle EM of recombinant MUC5B N terminus (D1D2D'D3; NT5B) and subdomains (D1, D1-D2, D2-D'-D3, and D3) generated structural models of monomers and disulfide-linked dimers and suggested that MUC5B multimerizes by disulfide linkage between D3-domains to form linear polymer chains. Moreover, these analyses revealed reversible homotypic interactions of NT5B at low pH and in high calcium, between disulfide-linked NT5B dimers, but not monomers. These results enable a model of MUC5B to be derived, which predicts mechanisms of mucin intracellular assembly and storage, which may be common to the other major gel-forming polymeric mucins.
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Assembly of the Respiratory Mucin MUC5B
Journal of Biological Chemistry, 2014Co-Authors: Caroline Ridley, Nikos Kouvatsos, Marj Howard, Richard F. Collins, Jean Luc Desseyn, Thomas A. Jowitt, Clair Baldock, C. William Davis, Bertrand D Raynal, Timothy E. HardinghamAbstract:Mucins are essential components in mucus gels that form protective barriers at all epithelial surfaces, but much remains unknown about their assembly, intragranular organization, and post-secretion unfurling to form mucus. MUC5B is a major polymeric mucin expressed by respiratory epithelia, and we investigated the molecular mechanisms involved during its assembly. Studies of intact polymeric MUC5B revealed a single high affinity calcium-binding site, distinct from multiple low affinity sites on each MUC5B monomer. Self-diffusion studies with intact MUC5B showed that calcium binding at the protein site catalyzed reversible cross-links between MUC5B chains to form networks. The site of cross-linking was identified in the MUC5B D3-domain as it was specifically blocked by D3 peptide antibodies. Biophysical analysis and single particle EM of recombinant MUC5B N terminus (D1D2D'D3; NT5B) and subdomains (D1, D1-D2, D2-D'-D3, and D3) generated structural models of monomers and disulfide-linked dimers and suggested that MUC5B multimerizes by disulfide linkage between D3-domains to form linear polymer chains. Moreover, these analyses revealed reversible homotypic interactions of NT5B at low pH and in high calcium, between disulfide-linked NT5B dimers, but not monomers. These results enable a model of MUC5B to be derived, which predicts mechanisms of mucin intracellular assembly and storage, which may be common to the other major gel-forming polymeric mucins.
Ingemar Carlstedt - One of the best experts on this subject based on the ideXlab platform.
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new monoclonal antibodies to non glycosylated domains of the secreted mucins MUC5B and muc7
Hybridoma and Hybridomics, 2003Co-Authors: Karine Rousseau, Claes Wickström, D B Whitehouse, Ingemar Carlstedt, Dallas M SwallowAbstract:The separation and characterization of salivary mucins is not straightforward because of their large size, heterogeneity, and molecular interactions. The MUC5B and MUC7 mucins are major glycoprotein components of saliva that are thought to play a vital role in maintaining oral health. MUC5B is also a major component of respiratory mucus and is produced by the tracheal and bronchial glands, while MUC7 has a more limited pattern of expression in the bronchial tree. MUC5B is a gel-forming mucin and thus confers viscosity, whereas MUC7 is much smaller. MUC7 has anti-fungal activity, and both mucins interact with bacteria. The aim of this work was to produce new monoclonal antibodies that can be used to quantify and characterize these mucins by standard laboratory procedures. Peptide sequences in non-conserved and non-glycosylated regions were selected and monoclonal antibodies produced by an efficient immunization and cloning strategy, and screening against purified mucins. Three new antibodies-EU-MUC5Ba and EU-MUC5Bb (against MUC5B) and EU-MUC7a (against MUC7)-were isolated that do not show cross-reactivity with other gel-forming mucins. All work on immunohistochemistry can be used for semi-quantitative immunoblotting after agarose gel electrophoresis. These reagents are valuable tools to study changes in these mucins in oral and respiratory disease, and unlike other monoclonal antibodies to these mucins they recognize epitopes that are not affected by glycosylation.
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N-terminal cleavage of the salivary MUC5B mucin. Analogy with the Van Willebrand propolypeptide?
The Journal of biological chemistry, 2001Co-Authors: Claes Wickström, Ingemar CarlstedtAbstract:Sequence similarities between the oligomeric mucins (MUC2, MUC5AC, MUC5B) and the von Willebrand factor suggest that they may be assembled in a similar way. After oligomerization, a fragment corresponding to the D1 and D2 domains is released from the von Willebrand factor. This cleavage does not appear to occur in pig submaxillary mucin, the only mammalian mucin in which this cleavage has been examined thus far, but whether other oligomeric mucins undergo N terminus proteolysis is not known. Antibodies recognizing the D1, D2, D3, and the first Cys domains in MUC5B were established and used to investigate to what extent proteolytic cleavage occurs within the N-terminal part of salivary MUC5B. The antibodies against the D1 and D2 domains identified a polypeptide corresponding in size to a MUC5B fragment generated by cleavage within the D' domain analogously with the von Willebrand factor propolypeptide. The antibodies did not recognize the main mucin population, suggesting that the major part of salivary MUC5B is subjected to this cleavage. An antibody recognizing the D3 domain was used to reveal a second cleavage site in the "soluble" but not in the "insoluble" MUC5B fraction: the first structural difference observed between soluble and insoluble salivary MUC5B. The identification of these cleavage events shows that the N-terminal sites for MUC5B oligomerization are present in the D3 domain and/or in domains located C-terminal to this part of the molecule.
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Identification of MUC5B, MUC5AC and small amounts of MUC2 mucins in cystic fibrosis airway secretions.
Biochemical Journal, 1999Co-Authors: Julia R. Davies, Naila Svitacheva, Louise Lannefors, Ragnhild Kornfält, Ingemar CarlstedtAbstract: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. (Less)
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MUC5B is a major gel forming oligomeric mucin from human salivary gland respiratory tract and endocervix identification of glycoforms and c terminal cleavage
Biochemical Journal, 1998Co-Authors: Claes Wickström, Julia R. Davies, Enno C. I. Veerman, Gitte V Eriksen, Ingemar CarlstedtAbstract:Mucins from human whole saliva, as well as from respiratory- and cervical-tract secretions, were subjected to density-gradient centrifugation in CsCl/0.5 M guanidinium chloride. A polydisperse population of MUC5B mucins was demonstrated in all samples using anti-peptide antisera (LUM5B-2, LUM5B-3 and LUM5B-4) raised against sequences within the MUC5B mucin. The sequences recognized by the LUM5B-2 and LUM5B-3 antisera are located within the domains flanking the highly glycosylated regions of MUC5B, and reduction increased the reactivity with these antibodies, suggesting that the epitopes are partially shielded and that these regions are folded and stabilized by disulphide bonds. Rate-zonal centrifugation before and after reduction showed MUC5B to be a large oligomeric mucin composed of disulphide-linked subunits. In saliva and respiratory-tract secretions, populations of MUC5B mucins with different charge densities were identified by ion-exchange HPLC, suggesting the presence of MUC5B ‘glycoforms ’. In trachea, the F2 monoclonal antibody against the sulpho-Lewis C structure reacted preferentially with the later-to-be-eluted populations. An antibody (LUM5B-4) recognizing a sequence in the C-terminal domain of MUC5B identified, after reduction, the mucin subunits as well as smaller fragments, suggesting that some of the MUC5B mucins are cleaved within the C-terminal domain. Immunohistochemistry revealed that MUC5B is produced by cells dispersed throughout the human submandibular and sublingual glands, in the airway submucosal glands as well as the goblet cells, and in the epithelium and glands of the endocervix. The F2 antibody stained a subpopulation of the MUC5B-producing cells in the airway submucosal glands, suggesting that different cells may produce different glycoforms of MUC5B in this tissue.
Amélie Velghe - One of the best experts on this subject based on the ideXlab platform.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor-1 (TTF-1) and GATA-6 transcription factors.
FEBS Journal, 2011Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.
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The mouse MUC5B mucin gene is transcriptionally regulated by thyroid transcription factor‐1 (TTF‐1) and GATA‐6 transcription factors
The FEBS journal, 2010Co-Authors: Nicolas Jonckheere, Amélie Velghe, Marie-paule Ducourouble, Marie-christine Copin, Ingrid B. Renes, Isabelle Van SeuningenAbstract:MUC5B is one of the major mucin genes expressed in the respiratory tract. Previous studies in our laboratory have demonstrated that MUC5B is expressed in human lung adenocarcinomas and during lung morphogenesis. Moreover, in human lung adenocarcinoma tissues, a converse correlation between MUC5B and thyroid transcription factor-1 (TTF-1) expression, a lung-specific transcription factor, has been established. However, the molecular mechanisms that govern the regulation of MUC5B expression in the lung are largely unknown. In order to better understand the biological role of MUC5B in lung pathophysiology, we report the characterization of the promoter region of the mouse MUC5B mucin gene. The promoter is flanked by a TATA box (TACATAA) identical to that in the human gene. Human and murine promoters share 67.5% similarity over the first 170 nucleotides. By RT-PCR, co-transfection studies and gel-shift assays, we show that MUC5B promoter activity is completely inhibited by TTF-1, whereas factors of the GATA family (GATA-4/GATA-5/GATA-6) are activators. Together, these results demonstrate, for the first time, that MUC5B is a target gene of transcription factors (TTF-1, GATA-6) involved in lung differentiation programs during development and carcinogenesis, and identify TTF-1 as a strong repressor of MUC5B. The characterization of the structural and functional features of the MUC5B mucin gene will provide us with a strong base to develop studies in murine models aimed at the identification of its biological role in lung pathophysiology.