Hydroxytyrosol modulates the levels of microRNA-9 and its target sirtuin-1 thereby counteracting oxidative stress-induced chondrocyte death

Stefania D'Adamo, S. Cetrullo, S Guidotti, R. M. Borzì, F. Flamigni

Research output: Contribution to journalArticlepeer-review


Objective Nutraceutical compounds, such as hydroxytyrosol (HT), have been found to exert protective effects in osteoarthritis (OA) by affecting a variety of key molecular and cellular processes in chondrocytes. However, to our knowledge, no relationship has been reported between nutraceuticals and microRNA (miR) network in OA models. Here, we identified a miR that is implicated in HT-mediated chondroprotection following oxidative stress condition by targeting sirtuin-1 (SIRT-1). Methods Human primary and C-28/I2 chondrocytes were pre-treated with 100 μM HT 30 min before 100 μM H2O2 addition. In silico analyses were exploited to select putative candidate miRs able to target SIRT-1 mRNA. Luciferase-based gene reporter assay was employed to demonstrate the direct link between miR-9 and its putative mRNA target. Transient transfection approach was performed to examine the effects of miR-9 levels on caspase activity, cell viability and expression of OA-related genes. Results MiR-9 was identified and confirmed as a post-transcriptional regulator of SIRT-1. MiR-9 and SIRT-1 levels showed opposite changes in chondrocytes following H2O2 and HT treatment. Moreover mir-9 silencing inhibited cell death induced by H2O2 partly through down-regulation of SIRT-1, whereas miR-9 overexpression markedly reduced the protective effect of HT. The manipulation of miR-9 levels also resulted in the modulation of OA-related gene expression, including MMP-13, VEGF and RUNX-2. Conclusions These results show that miR-9 is a critical mediator of the deleterious and OA-related effects of oxidative stress in chondrocytes and that modulation of miR expression may be a crucial mechanism underlying the protective action of HT.

Original languageEnglish
Pages (from-to)600-610
Number of pages11
JournalOsteoarthritis and Cartilage
Issue number4
Publication statusPublished - Apr 1 2017


  • Cartilage
  • Chondrocyte
  • Hydroxytyrosol
  • microRNA
  • Oxidative stress

ASJC Scopus subject areas

  • Rheumatology
  • Orthopedics and Sports Medicine
  • Biomedical Engineering


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