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Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration
BACKGROUND: The role of miRNAs in the pathogenesis and determining the phenotypes of asthma is not fully elucidated. miR-146a has been previously shown to suppress inflammatory responses in different cells. In this study, we investigated the functions of miR-146a in human bronchial epithelial cells...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880603/ https://www.ncbi.nlm.nih.gov/pubmed/31798831 http://dx.doi.org/10.1186/s13601-019-0301-8 |
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author | Kivihall, Anet Aab, Alar Soja, Jerzy Sładek, Krzysztof Sanak, Marek Altraja, Alan Jakiela, Bogdan Bochenek, Grazyna Rebane, Ana |
author_facet | Kivihall, Anet Aab, Alar Soja, Jerzy Sładek, Krzysztof Sanak, Marek Altraja, Alan Jakiela, Bogdan Bochenek, Grazyna Rebane, Ana |
author_sort | Kivihall, Anet |
collection | PubMed |
description | BACKGROUND: The role of miRNAs in the pathogenesis and determining the phenotypes of asthma is not fully elucidated. miR-146a has been previously shown to suppress inflammatory responses in different cells. In this study, we investigated the functions of miR-146a in human bronchial epithelial cells (HBECs) in association with neutrophilic, eosinophilic, and paucigranulocytic phenotypes of asthma. METHODS: Bronchial brushing specimens and brochial mucosal biopsy samples were collected from adult patients with asthma and from age- and gender-matched non-asthmatic individuals. The expression of miR-146a in bronchial brushing specimens, bronchial biopsy tissue sections or cultured primary bronchial epithelial cells was analyzed by RT-qPCR or by in situ hybridization. The expression of direct and indirect miR-146a target genes was determined by RT-qPCR or ELISA. The migration of neutrophils was studied by neutrophil chemotaxis assay and flow cytometry. For statistical analysis, unpaired two-way Student’s t test, one-way ANOVA or linear regression analysis were used. RESULTS: Reduced expression of miR-146a was found in bronchial brushing specimens from asthma patients as compared to non-asthmatics and irrespective of the phenotype of asthma. In the same samples, the neutrophil attracting chemokines IL-8 and CXCL1 showed increased expression in patients with neutrophilic asthma and increased IL-33 expression was found in patients with eosinophilic asthma. Linear regression analysis revealed a significant negative association between the expression of miR-146a in bronchial brushings and neutrophil cell counts in bronchoalveolar lavage fluid of patients with asthma. In bronchial biopsy specimens, the level of miR-146a was highest in the epithelium as determined with in situ hybridization. In primary conventional HBEC culture, the expression of miR-146a was induced in response to the stimulation with IL-17A, TNF-α, and IL-4. The mRNA expression and secretion of IL-8 and CXCL1 was inhibited in both stimulated and unstimulated HBECs transfected with miR-146a mimics. Supernatants from HBECs transfected with miR-146a had reduced capability of supporting neutrophil migration in neutrophil chemotaxis assay. CONCLUSION: Our results suggest that decreased level of miR-146a in HBECs from patients with asthma may contribute to the development of neutrophilic phenotype of asthma. |
format | Online Article Text |
id | pubmed-6880603 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-68806032019-12-03 Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration Kivihall, Anet Aab, Alar Soja, Jerzy Sładek, Krzysztof Sanak, Marek Altraja, Alan Jakiela, Bogdan Bochenek, Grazyna Rebane, Ana Clin Transl Allergy Research BACKGROUND: The role of miRNAs in the pathogenesis and determining the phenotypes of asthma is not fully elucidated. miR-146a has been previously shown to suppress inflammatory responses in different cells. In this study, we investigated the functions of miR-146a in human bronchial epithelial cells (HBECs) in association with neutrophilic, eosinophilic, and paucigranulocytic phenotypes of asthma. METHODS: Bronchial brushing specimens and brochial mucosal biopsy samples were collected from adult patients with asthma and from age- and gender-matched non-asthmatic individuals. The expression of miR-146a in bronchial brushing specimens, bronchial biopsy tissue sections or cultured primary bronchial epithelial cells was analyzed by RT-qPCR or by in situ hybridization. The expression of direct and indirect miR-146a target genes was determined by RT-qPCR or ELISA. The migration of neutrophils was studied by neutrophil chemotaxis assay and flow cytometry. For statistical analysis, unpaired two-way Student’s t test, one-way ANOVA or linear regression analysis were used. RESULTS: Reduced expression of miR-146a was found in bronchial brushing specimens from asthma patients as compared to non-asthmatics and irrespective of the phenotype of asthma. In the same samples, the neutrophil attracting chemokines IL-8 and CXCL1 showed increased expression in patients with neutrophilic asthma and increased IL-33 expression was found in patients with eosinophilic asthma. Linear regression analysis revealed a significant negative association between the expression of miR-146a in bronchial brushings and neutrophil cell counts in bronchoalveolar lavage fluid of patients with asthma. In bronchial biopsy specimens, the level of miR-146a was highest in the epithelium as determined with in situ hybridization. In primary conventional HBEC culture, the expression of miR-146a was induced in response to the stimulation with IL-17A, TNF-α, and IL-4. The mRNA expression and secretion of IL-8 and CXCL1 was inhibited in both stimulated and unstimulated HBECs transfected with miR-146a mimics. Supernatants from HBECs transfected with miR-146a had reduced capability of supporting neutrophil migration in neutrophil chemotaxis assay. CONCLUSION: Our results suggest that decreased level of miR-146a in HBECs from patients with asthma may contribute to the development of neutrophilic phenotype of asthma. BioMed Central 2019-11-27 /pmc/articles/PMC6880603/ /pubmed/31798831 http://dx.doi.org/10.1186/s13601-019-0301-8 Text en © The Author(s) 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Kivihall, Anet Aab, Alar Soja, Jerzy Sładek, Krzysztof Sanak, Marek Altraja, Alan Jakiela, Bogdan Bochenek, Grazyna Rebane, Ana Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title | Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title_full | Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title_fullStr | Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title_full_unstemmed | Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title_short | Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration |
title_sort | reduced expression of mir-146a in human bronchial epithelial cells alters neutrophil migration |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880603/ https://www.ncbi.nlm.nih.gov/pubmed/31798831 http://dx.doi.org/10.1186/s13601-019-0301-8 |
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