All-Trans-Retinoic Acid Enhances Mitochondrial Function in Models of Human Liver
Authors: Nina Isoherranen
John D Chapman
David R Goodlett
Travis Kent
Samuel L M Arnold
Jennifer Onken
Cathryn A Hogarth
Sasmita Tripathy
Chang Y Han
Journal: Molecular Pharmacology (2016)
Discipline: PHARMACOLOGY & TOXICOLOGY
Keywords: all-trans-retinoic acid; liver; mitochondrial function; mitochondrial biogenesis; beta-oxidation
Affiliations: Departments of Pharmaceutics (S.T., S.L.M.A., N.I.), Medicinal Chemistry (J.D.C., D.R.G.), and Diabetes Obesity Center for Excellence and the Department of Medicine, Division of Metabolism, Endocrinology and Nutrition (C.Y.H.), University of Washington, Seattle, Washington; School of Molecular Biosciences and The Center for Reproductive Biology, Washington State University, Pullman, Washington (C.A.H., J.O., T.K.); and School of Pharmacy, University of Maryland, Baltimore, Maryland (D.R.G.)., Departments of Pharmaceutics (S.T., S.L.M.A., N.I.), Medicinal Chemistry (J.D.C., D.R.G.), and Diabetes Obesity Center for Excellence and the Department of Medicine, Division of Metabolism, Endocrinology and Nutrition (C.Y.H.), University of Washington, Seattle, Washington; School of Molecular Biosciences and The Center for Reproductive Biology, Washington State University, Pullman, Washington (C.A.H., J.O., T.K.); and School of Pharmacy, University of Maryland, Baltimore, Maryland (D.R.G.) .

Abstract:  All-trans-retinoic acid (atRA) is the active metabolite of vitamin A. The liver is the main storage organ of vitamin A, but activation of the retinoic acid receptors (RARs) in mouse liver and in human liver cell lines has also been shown. AlthoughatRA treatment improves mitochondrial function in skeletal muscle in rodents, its role in modulating mitochondrial function in the liver is controversial, and little data are available regarding the human liver. The aim of this study was to determine whetheratRA regulates hepatic mitochondrial activity.atRA treatment increased the mRNA and protein expression of multiple components of mitochondrialβ-oxidation, tricarboxylic acid (TCA) cycle, and respiratory chain. Additionally,atRA increased mitochondrial biogenesis in human hepatocytes and in HepG2 cells with and without lipid loading based on peroxisome proliferator activated receptor gamma coactivator 1αand 1βand nuclear respiratory factor 1 mRNA and mitochondrial DNA quantification.atRA also increasedβ-oxidation and ATP production in HepG2 cells and in human hepatocytes. Knockdown studies of RARα, RARβ, and PPARδrevealed that the enhancement of mitochondrial biogenesis andβ-oxidation byatRA requires peroxisome proliferator activated receptor delta. In vivo in mice,atRA treatment increased mitochondrial biogenesis markers after an overnight fast. Inhibition ofatRA metabolism by talarozole, a cytochrome P450 (CYP) 26 specific inhibitor, increased the effects ofatRA on mitochondrial biogenesis markers in HepG2 cells and in vivo in mice. These studies show thatatRA regulates mitochondrial function and lipid metabolism and that increasingatRA concentrations in human liver via CYP26 inhibition may increase mitochondrial biogenesis and fatty acidβ-oxidation and provide therapeutic benefit in diseases associated with mitochondrial dysfunction. 

Retracted: Yes

PubPeer comments:
 2020 retraction. http: molpharm.aspetjournals.org content 97 2 61 At the request of Dr. Nina Isoherranen and with the concurrence of all the coauthors except the first author, Molecular Pharmacology has retracted this article. It was found that the first author intentionally fabricated and or falsified data and analyses represented by Figs. 2A, 3D, 4A, 4F, 5B, 5E, 6B, 6C, and Supplemental Fig. 2a, and in the western blot image found in Supplemental Fig. 2B. ,