Abstract
Aims and objectives: Smoking is a risk factor for idiopathic pulmonary fibrosis (IPF), but the associated mechanism remains unknown. Our aim was to study the RNA-regulatory networks of the stress-responsive RNA-binding protein HuR and what impact it has on the disease pathology.
Methods: TGF-β1-activated human lung fibroblasts were used to study the effect of cigarette smoke extract (CSE) stimulation on the translocation HuR from the nucleus to the cytoplasm. HuR-specific RNA-interactions in the nuclear and cytoplasmic cell fractions were analyzed by CLIP (cross-linking and immunoprecipitation) and subsequent high-throughput sequencing.
Results: We showed that CSE induces HuR translocation from the nucleus to the cytoplasm in TGF-β1-activated lung fibroblasts. CLIP data revealed several fibrotic genes, including COL1A1 and COL1A2, among the most frequently bound HuR-targets in the cytoplasm. Evaluation of HuR-bound RNA sequences showed a difference in 4-meric binding motifs between nuclear and cytoplasmic HuR fractions, with increased binding to polyU-rich RNA motifs in the cytoplasm. Interestingly, the polyU-rich binding was reduced upon TGF-β1/CSE stimulation. Additionally, the TGF-β1/CSE stimulation led to reduced binding of cytoplasmic HuR to 3’UTR RNA regions and increased interaction with the coding regions.
Conclusions: Our data suggests a global shift of HuR function from 3’UTR-dependent RNA stabilization, potentially in the direction of translational regulation of genes associated with fibrosis.
Footnotes
Cite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA2397.
This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2021