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Exp Gerontol. 2017 Oct 1;96:110-122. doi: 10.1016/j.exger.2017.06.017. Epub 2017 Jun 27.

Senescence-associated microRNAs target cell cycle regulatory genes in normal human lung fibroblasts.

Author information

1
Laboratory of Biology, School of Medicine, Faculty of Health Sciences, University of Ioannina, Greece; Biomedical Research Division, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, 45110 Ioannina, Greece.
2
Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece.
3
Molecular Biology Unit, Hematology Laboratory, University Hospital of Ioannina, 45110 Ioannina, Greece.
4
Laboratory of Biology, School of Medicine, Faculty of Health Sciences, University of Ioannina, Greece.
5
Biosciences Division, Interdisciplinary Biomedical Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham MG11 8NS,United Kingdom.
6
Biomedical Research Division, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, 45110 Ioannina, Greece.
7
Laboratory of Biology, School of Medicine, Faculty of Health Sciences, University of Ioannina, Greece; Biomedical Research Division, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, 45110 Ioannina, Greece. Electronic address: ekoletas@cc.uoi.gr.

Abstract

Senescence recapitulates the ageing process at the cell level. A senescent cell stops dividing and exits the cell cycle. MicroRNAs (miRNAs) acting as master regulators of transcription, have been implicated in senescence. In the current study we investigated and compared the expression of miRNAs in young versus senescent human fibroblasts (HDFs), and analysed the role of mRNAs expressed in replicative senescent HFL-1 HDFs. Cell cycle analysis confirmed that HDFs accumulated in G1/S cell cycle phase. Nanostring analysis of isolated miRNAs from young and senescent HFL-1 showed that a distinct set of 15 miRNAs were significantly up-regulated in senescent cells including hsa-let-7d-5p, hsa-let-7e-5p, hsa-miR-23a-3p, hsa-miR-34a-5p, hsa-miR-122-5p, hsa-miR-125a-3p, hsa-miR-125a-5p, hsa-miR-125b-5p, hsa-miR-181a-5p, hsa-miR-221-3p, hsa-miR-222-3p, hsa-miR-503-5p, hsa-miR-574-3p, hsa-miR-574-5p and hsa-miR-4454. Importantly, pathway analysis of miRNA target genes down-regulated during replicative senescence in a public RNA-seq data set revealed a significant high number of genes regulating cell cycle progression, both G1/S and G2/M cell cycle phase transitions and telomere maintenance. The reduced expression of selected miRNA targets, upon replicative and oxidative-stress induced senescence, such as the cell cycle effectors E2F1, CcnE, Cdc6, CcnB1 and Cdc25C was verified at the protein and/or RNA levels. Induction of G1/S cell cycle phase arrest and down-regulation of cell cycle effectors correlated with the up-regulation of miR-221 upon both replicative and oxidative stress-induced senescence. Transient expression of miR-221/222 in HDFs promoted the accumulation of HDFs in G1/S cell cycle phase. We propose that miRNAs up-regulated during replicative senescence may act in concert to induce cell cycle phase arrest and telomere erosion, establishing a senescent phenotype.

KEYWORDS:

Cell cycle effectors; Cellular senescence; Human lung fibroblasts; MicroRNAs

PMID:
28658612
DOI:
10.1016/j.exger.2017.06.017
[Indexed for MEDLINE]

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