1. Academic Validation
  2. Ouabagenin is a naturally occurring LXR ligand without causing hepatic steatosis as a side effect

Ouabagenin is a naturally occurring LXR ligand without causing hepatic steatosis as a side effect

  • Sci Rep. 2018 Feb 2;8(1):2305. doi: 10.1038/s41598-018-20663-z.
Satoru Tamura 1 2 Maiko Okada 3 4 Shigeaki Kato 5 6 Yasuharu Shinoda 7 Norifumi Shioda 7 Kohji Fukunaga 7 Kumiko Ui-Tei 8 Minoru Ueda 9
Affiliations

Affiliations

  • 1 Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan.
  • 2 School of Pharmacy, Iwate Medical University, Shiwa-gun, Iwate, 028-3694, Japan.
  • 3 Institute of Medical Science, St. Marianna University Graduate School of Medicine, Kawasaki, Kanagawa, 970-8551, Japan.
  • 4 Genome regulation and Molecular Pharmacogenomics, School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, 192-0982, Japan.
  • 5 Iwaki Meisei University, Iwaki, Fukushima, 970-8551, Japan.
  • 6 Research Institute of Innovative Medicine, Tokiwa Foundation, Iwaki, Fukushima, 972-8322, Japan.
  • 7 Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan.
  • 8 Graduate School of Science, The University of Tokyo, Tokyo, 113-0032, Japan.
  • 9 Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi, 980-8578, Japan. [email protected].
Abstract

Ouabagenin (OBG) is an aglycone of the cardiotonic steroid ouabain and until now was considered a biologically inactive biosynthetic precursor. Herein, we revealed that OBG functions as a novel class of ligand for the liver X receptor (LXR). Luciferase reporter assays and in silico docking studies suggested that OBG has LXR-selective agonistic activity. In addition, OBG repressed the expression of epithelial Sodium Channel (ENaC), a LXR target gene, without causing hepatic steatosis, a typical side effect of conventional LXR ligands. This remarkable biological activity can be attributed to a unique mode of action; the LXR Agonist activity mainly proceeds through the LXRβ subtype without affecting LXRα, unlike conventional LXR ligands. Thus, OBG is a novel class of LXR ligand that does not cause severe side effects, with potential for use as an antihypertensive diuretic or a tool compound for exploring LXR subtype-specific biological functions.

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