Expression of targets of the RNA-binding protein AUF-1 in human airway epithelium indicates its role in cellular senescence and inflammation
Author(s)
Type
Journal Article
Abstract
INTRODUCTION: The RNA-binding protein AU-rich-element factor-1 (AUF-1) participates to posttranscriptional regulation of genes involved in inflammation and cellular senescence, two pathogenic mechanisms of chronic obstructive pulmonary disease (COPD). Decreased AUF-1 expression was described in bronchiolar epithelium of COPD patients versus controls and in vitro cytokine- and cigarette smoke-challenged human airway epithelial cells, prompting the identification of epithelial AUF-1-targeted transcripts and function, and investigation on the mechanism of its loss. RESULTS: RNA immunoprecipitation-sequencing (RIP-Seq) identified, in the human airway epithelial cell line BEAS-2B, 494 AUF-1-bound mRNAs enriched in their 3'-untranslated regions for a Guanine-Cytosine (GC)-rich binding motif. AUF-1 association with selected transcripts and with a synthetic GC-rich motif were validated by biotin pulldown. AUF-1-targets' steady-state levels were equally affected by partial or near-total AUF-1 loss induced by cytomix (TNFα/IL1β/IFNγ/10 nM each) and siRNA, respectively, with differential transcript decay rates. Cytomix-mediated decrease in AUF-1 levels in BEAS-2B and primary human small-airways epithelium (HSAEC) was replicated by treatment with the senescence- inducer compound etoposide and associated with readouts of cell-cycle arrest, increase in lysosomal damage and senescence-associated secretory phenotype (SASP) factors, and with AUF-1 transfer in extracellular vesicles, detected by transmission electron microscopy and immunoblotting. Extensive in-silico and genome ontology analysis found, consistent with AUF-1 functions, enriched RIP-Seq-derived AUF-1-targets in COPD-related pathways involved in inflammation, senescence, gene regulation and also in the public SASP proteome atlas; AUF-1 target signature was also significantly represented in multiple transcriptomic COPD databases generated from primary HSAEC, from lung tissue and from single-cell RNA-sequencing, displaying a predominant downregulation of expression. DISCUSSION: Loss of intracellular AUF-1 may alter posttranscriptional regulation of targets particularly relevant for protection of genomic integrity and gene regulation, thus concurring to airway epithelial inflammatory responses related to oxidative stress and accelerated aging. Exosomal-associated AUF-1 may in turn preserve bound RNA targets and sustain their function, participating to spreading of inflammation and senescence to neighbouring cells.
Date Issued
2023-07-07
Date Acceptance
2023-06-06
Citation
Frontiers in Immunology, 2023, 14, pp.1-27
ISSN
1664-3224
Publisher
Frontiers Media S.A.
Start Page
1
End Page
27
Journal / Book Title
Frontiers in Immunology
Volume
14
Copyright Statement
Copyright © 2023 Salvato, Ricciardi, Dal Col, Nigro, Giurato, Memoli, Sellitto, Lamparelli, Crescenzi, Vitale, Vatrella, Nucera, Brun, Caicci, Dama, Stiff, Castellano, Idrees, Johansen, Faiz, Wark, Hansbro, Adcock, Caramori and Stellato. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/37483631
Subjects
Cellular Senescence
Epithelial Cells
Epithelium
Humans
Inflammation
Pulmonary Disease, Chronic Obstructive
RNA
RNA-Binding Proteins
airway epithelium
AU-rich element factor 1 (AUF-1)
cell senescence
chronic inflammation
chronic obstructive pulmonary disease
inflammaging
oxidative stress
RNA-binding proteins
Publication Status
Published
Coverage Spatial
Switzerland
Article Number
1192028
Date Publish Online
2023-07-07