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SIRT1 modulates miRNA processing defects in p53-mutated human keratinocytes

Citation

Herbert, KJ and Cook, AL and Snow, ET, SIRT1 modulates miRNA processing defects in p53-mutated human keratinocytes, Journal of Dermatological Science, 74, (2) pp. 142-149. ISSN 0923-1811 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 Elsevier

DOI: doi:10.1016/j.jdermsci.2014.01.008

Abstract

Background: Together with p53, the NAD-dependent lysine deacetylase SIRT1 and the microRNA miR-34a form a feedback loop which self-regulates SIRT1 expression and modulates p53-dependent responses. In addition to its well-described role in mediating transcriptional responses to genotoxic stress, p53 may also regulate microRNA processing and maturation.

Objective: This study explored the functional relationship among p53, SIRT1 and miR-34a, and the influence of p53 and SIRT1 on microRNA biogenesis and maturation in primary (NHEK) and p53-mutated (HaCaT) keratinocyte cell lines.

Methods: RNAi, miRNA target site blocking oligonucleotides and small molecule inhibitors were used to modulate activity and expression of SIRT1 and p53. Changes in microRNA and mRNA were analysed by qRT-PCR and protein expression was determined by immunoblotting.

Results: Mature miR-34a decreased in p53-suppressed NHEK cells, whereas ablation of SIRT1 reduced the primary transcript (pri-miR-34a). When either SIRT1 expression or activity was inhibited in combination with p53 ablation, pri-miR-34a levels increased and mature miR-34a levels decreased. Under these same conditions, additional p53-regulated microRNAs (miRs 16-1/15, 145 and 107) also failed to mature. In HaCaT cells, primary microRNA transcripts for miR-16-1/15, miR-145 miR200c/141 and miRNA-107, but not miR-34a, were approximately 8-fold higher than in NHEK cells. However, the levels of mature microRNA sequences in HaCaT cells were only 1.52 fold higher (miR-16-1, miR-145), unchanged (miR-107) or decreased (miR-200c/141, miR-34a) compared to NHEK cells.

Conclusions: Our results suggest that p53 mutations interfere with efficient microRNA biogenesis in keratinocytes, and that SIRT1 functions in combination with p53 in this process.

Item Details

Item Type:Refereed Article
Keywords:SIRT1, miRNA, p53, keratinocytes
Research Division:Biological Sciences
Research Group:Biochemistry and Cell Biology
Research Field:Cell Development, Proliferation and Death
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Medical and Health Sciences
Author:Herbert, KJ (Ms Katharine Herbert)
Author:Cook, AL (Dr Tony Cook)
Author:Snow, ET (Associate Professor Elizabeth Snow)
ID Code:90244
Year Published:2014
Web of Science® Times Cited:7
Deposited By:Health Sciences A
Deposited On:2014-03-31
Last Modified:2015-04-13
Downloads:0

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