Genetic variation in SP-A2 leads to differential binding to Mycoplasma pneumoniae membranes and regulation of host responses.
J Immunol
; 194(12): 6123-32, 2015 Jun 15.
Article
em En
| MEDLINE
| ID: mdl-25957169
ABSTRACT
Mycoplasma pneumoniae is an extracellular pathogen that colonizes mucosal surfaces of the respiratory tract and is associated with asthma exacerbations. Previous reports demonstrate that surfactant protein-A (SP-A) binds live M. pneumoniae and mycoplasma membrane fractions (MMF) with high affinity. Humans express a repertoire of single-amino acid genetic variants of SP-A that may be associated with lung disease, and our findings demonstrate that allelic differences in SP-A2 (Gln223Lys) affect the binding to MMF. We show that SP-A(-/-) mice are more susceptible to MMF exposure and have significant increases in mucin production and neutrophil recruitment. Novel humanized SP-A2-transgenic mice harboring the hSP-A2 223K allele exhibit reduced neutrophil influx and mucin production in the lungs when challenged with MMF compared with SP-A(-/-) mice. Conversely, mice expressing hSP-A2 223Q have increased neutrophil influx and mucin production that are similar to SP-A(-/-) mice. Using tracheal epithelial cell cultures, we show that enhanced mucin production to MMF occurs in the absence of SP-A and is not dependent upon neutrophil recruitment. Increased phosphorylation of the epidermal growth factor receptor (EGFR) was evident in the lungs of MMF-challenged mice when SP-A was absent. Pharmacologic inhibition of EGFR prior to MMF challenge dramatically reduced mucin production in SP-A(-/-) mice. These findings suggest a protective role for SP-A in limiting MMF-stimulated mucin production that occurs through interference with EGFR-mediated signaling. SP-A interaction with the EGFR signaling pathway appears to occur in an allele-specific manner that may have important implications for SP-A polymorphisms in human diseases.
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Bases de dados:
MEDLINE
Assunto principal:
Pneumonia por Mycoplasma
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Variação Genética
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Proteína A Associada a Surfactante Pulmonar
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Interações Hospedeiro-Patógeno
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Mycoplasma pneumoniae
Limite:
Animals
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Female
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Humans
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Male
Idioma:
En
Revista:
J Immunol
Ano de publicação:
2015
Tipo de documento:
Article