Negative feedback regulation between microRNA let-7g and the oxLDL receptor LOX-1

Ku Chung Chen, I. Chung Hsieh, Edward Hsi, Yung Song Wang, Chia Yen Dai, Wen Wen Chou, Suh Hang Hank Juo

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

Abstract

Lectin-like oxidized LDL receptor-1 (LOX-1) is a surface scavenger receptor for oxidized low-density lipoprotein (oxLDL). Several transcription factors have been reported to regulate LOX-1 expression. MicroRNAs are small noncoding RNAs that control gene expression, but there have been no reports of LOX-1 expression being regulated by microRNAs. Because the microRNA let-7g has been predicted to bind to LOX-1 mRNA, we investigated whether let-7g can regulate LOX-1 expression. Our experiments first demonstrated that oxLDL can reduce let-7g expression. We later confirmed that there is a let-7g binding site on the 3'-untranslated region of LOX-1 mRNA. We showed that intracellular Ca 2+-activated protein kinase C is involved in the oxLDL-LOX-1-let-7g pathway. Bioinformatics predicted that the let-7g promoter has a binding site for the transcriptional repressor OCT-1. We used a promoter assay and chromatin immunoprecipitation to confirm this binding. Consequently, knockdown of OCT-1 was found to increase let-7g expression. Transfection of let-7g inhibited oxLDL-induced LOX-1 and OCT-1 expression, cell proliferation and migration. Mice fed with a high-fat diet showed a decrease in let-7g and an increase in LOX-1 and OCT-1. A study on humans showed the serum levels of let-7g are lower in subjects with hypercholesterolemia compared with normal controls. Our findings identify a negative feedback regulation between let-7g and LOX-1, and indicate that let-7g could be a target to treat cardiovascular disease.

Original languageEnglish
Pages (from-to)4115-4124
Number of pages10
JournalJournal of Cell Science
Volume124
Issue number23
DOIs
Publication statusPublished - Dec 2011
Externally publishedYes

Keywords

  • Atherosclerosis
  • Let-7g
  • LOX-1
  • Microrna
  • OxLDL

ASJC Scopus subject areas

  • Cell Biology

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