MiR-339 is a potential biomarker of coronary heart disease to aggravate oxidative stress through Nrf2/FOXO3 targeting Sirt2

BACKGROUND MicroRNA (miRNA) is a class of small-molecule RNA that can regulate gene expression at post-transcription level. It is involved in the genesis and development of multiple diseases. The aim of this paper was to explore the mechanisms of miR-339 in coronary heart disease (CHD). METHODS In this study, we enrolled patients with CHD from Beijing Chaoyang Hospital and performed animal experiments on CHD rats. In vitro experiments, such as histopathologic assay, quantitative real-time PCR assay, luciferase reporter assay, western blotting assay, and immunofluorescence assay were carried out to characterize the contents and associations of miR-339, Nrf2, FOXO3, and Sirt2 in CHD samples and cells. In vivo model was also established on rats. RESULTS In CHD rat, miR-339 was up-regulated compared with control group. The expression of miR-339 up-regulation increased oxidative stress in vitro model via suppression of Sirt2/Nrf2/FOXO3. However, down-regulation of miR-339 expression inhibited oxidative stress in vitro model via activation of Sirt2/Nrf2/FOXO3. The Sirt2 or Nrf2 inhibitor reduced the protective effect of miR-339 down-regulation on oxidative stress in vitro model. CONCLUSIONS Down-regulation miR-339 may be the new targets to treat CHD through Nrf2/FOXO3 targeting Sirt2, and miR-339 may be a potential biomarker of CHD.