Abstract | PURPOSE: Inflammatory gene expression is modulated by posttranscriptional regulation via RNA-binding proteins (RBPs), which regulate mRNA turnover and translation by binding to conserved mRNA sequences. Their role in COPD is only partially defined. This study evaluated RBPs tristetraprolin ( TTP), human antigen R (HuR), and AU-rich element-binding factor 1 (AUF-1) expression using lung tissue from COPD patients and control subjects and probed their function in epithelial responses in vitro. PATIENTS AND METHODS: RBPs were detected by immunohistochemistry in bronchial and peripheral lung samples from mild-to-moderate stable COPD patients and age/smoking history-matched controls; RBPs and RBP-regulated genes were evaluated by Western blot, ELISA, protein array, and real-time PCR in human airway epithelial BEAS-2B cell line stimulated with hydrogen peroxide, cytokine combination (cytomix), cigarette smoke extract (CSE), and following siRNA-mediated silencing. Results were verified in a microarray database from bronchial brushings of COPD patients and controls. RBP transcripts were measured in peripheral blood mononuclear cell samples from additional stable COPD patients and controls. RESULTS: Specific, primarily nuclear immunostaining for the RBPs was detected in structural and inflammatory cells in bronchial and lung tissues. Immunostaining for AUF-1, but not TTP or HuR, was significantly decreased in bronchial epithelium of COPD samples vs controls. In BEAS-2B cells, cytomix and CSE stimulation reproduced the RBP pattern while increasing expression of AUF-1-regulated genes, interleukin-6, CCL2, CXCL1, and CXCL8. Silencing expression of AUF-1 reproduced, but not enhanced, target upregulation induced by cytomix compared to controls. Analysis of bronchial brushing-derived transcriptomic confirmed the selective decrease of AUF-1 in COPD vs controls and revealed significant changes in AUF-1-regulated genes by genome ontology. CONCLUSION: Downregulated AUF-1 may be pathogenic in stable COPD by altering posttranscriptional control of epithelial gene expression.
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Authors | Luca Ricciardi, Jessica Dal Col, Paolo Casolari, Domenico Memoli, Valeria Conti, Alessandro Vatrella, Becky M Vonakis, Alberto Papi, Gaetano Caramori, Cristiana Stellato |
Journal | International journal of chronic obstructive pulmonary disease
(Int J Chron Obstruct Pulmon Dis)
2018
Vol. 13
Pg. 3173-3190
ISSN: 1178-2005 [Electronic] New Zealand |
PMID | 30349226
(Publication Type: Journal Article)
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Chemical References |
- Cytokines
- HNRNPD protein, human
- Heterogeneous Nuclear Ribonucleoprotein D0
- Heterogeneous-Nuclear Ribonucleoprotein D
- RNA, Small Interfering
- RNA-Binding Proteins
- Tristetraprolin
- ZFP36 protein, human
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Topics |
- Aged
- Bronchi
(pathology)
- Cytokines
(metabolism)
- Female
- Gene Expression Regulation
(physiology)
- Gene Silencing
(physiology)
- Heterogeneous Nuclear Ribonucleoprotein D0
- Heterogeneous-Nuclear Ribonucleoprotein D
(genetics)
- Humans
- Immunohistochemistry
- Inflammation
(metabolism)
- Male
- Middle Aged
- Pulmonary Disease, Chronic Obstructive
(metabolism, pathology)
- RNA, Small Interfering
(genetics)
- RNA-Binding Proteins
(genetics)
- Respiratory Mucosa
(pathology)
- Signal Transduction
- Smoking
(metabolism)
- Tristetraprolin
(genetics)
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