Munc134 mediates human neutrophil elastaseinduced airway mucin5AC hypersecretion by interacting with syntaxin2.
Mol Med Rep
; 18(1): 1015-1024, 2018 Jul.
Article
em En
| MEDLINE
| ID: mdl-29767240
ABSTRACT
The overexpression and hypersecretion of mucus is a hallmark of chronic pulmonary inflammatory disease. Mucin5AC (MUC5AC) is a major component of airway gelforming mucin. Members of the Unc13 (Munc13) protein family act as important activators of granule exocytosis from various types of mammalian cells. The present study aimed to determine the role of Munc13 family proteins in MUC5AC secretion via an in vitro study with BEAS2B and Calu3 cell lines. Reverse transcriptionquantitative polymerase chain reaction and western blotting indicated that stimulation of the cells with 100 nM human neutrophil elastase (hNE) for 1 h did not affect the expression of either unc13 homolog B (Munc132) or unc13 homolog D (Munc134), but immunofluorescence analysis demonstrated that hNE treatment was associated with the recruitment of Munc134 to the plasma membrane. Coimmunoprecipitation analysis indicated increased binding between Munc134 and syntaxin2 followingh NE stimulation; however, Munc132 formed a stable interaction with syntaxin2 with or without hNE stimulation. Subsequently, Munc132 and Munc134 expression levels were downregulated in BEAS2B and Calu3 cells using small interfering RNA (siRNA). ELISAs and immunofluorescence analysis were performed to assess MUC5AC secretion and intracellular retention, respectively. Munc132 siRNA transfection did not alter the expression levels of intracellular or secreted MUC5AC following hNE stimulation in either cell line; however, it increased the baseline intracellular levels of MUC5AC and decreased the amount of secreted MUC5AC. Conversely, Munc134 siRNA transfection increased the intracellular levels of MUC5AC and decreased the amount of secreted MUC5AC following hNE stimulation, but did not affect their baseline quantities. The results of the present study indicate that Munc132 may be an essential regulator of basal MUC5AC exocytosis, while Munc134 appears to be a Munc13 protein subtype that may to be sensitive to hNE stimulation during airway MUC5AC hypersecretion.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Elastase de Leucócito
/
Mucosa Respiratória
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Sintaxina 1
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Mucina-5AC
/
Proteínas de Membrana
Limite:
Humans
Idioma:
En
Revista:
Mol Med Rep
Ano de publicação:
2018
Tipo de documento:
Article