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 2014 Elsevier
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 1.5–2 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 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)|
|Web of Science® Times Cited:||7|
|Deposited By:||Health Sciences A|
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