Metformin protects rat hepatocytes against bile acid-induced apoptosis

• Published in: PloS one 2013-08, Vol.8 (8), p.e71773
• Main Authors: Woudenberg-Vrenken, Titia E, Conde de la Rosa, Laura, Buist-Homan, Manon, Faber, Klaas Nico, Moshage, Han
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; Acids; Acridine orange; Actinomycin; Activation; AKT protein; AMP; AMP-activated protein kinase; AMP-Activated Protein Kinases - metabolism; Animals; Antidiabetics; Apoptosis; Apoptosis - drug effects; Bile; Bile Acids and Salts - metabolism; Bile Acids and Salts - pharmacology; Biology; Caspase; Caspase 3 - metabolism; Cell death; Cell Membrane - metabolism; Deoxycholic acid; Diabetes mellitus; Diabetes therapy; Dose-Response Relationship, Drug; Fatty liver; Glycochenodeoxycholic Acid - metabolism; Hepatocytes; Hepatocytes - drug effects; Hepatocytes - metabolism; Hepatocytes - pathology; Hypoglycemic Agents - pharmacology; Kinases; Laboratories; Liver; Liver diseases; Male; Medical treatment; Medicine; Metformin; Metformin - pharmacology; Mortality; Necrosis - drug therapy; NF-kappa B - metabolism; NF-κB protein; Pharmacology; Phosphatidylinositol 3-Kinases - metabolism; Protein kinases; Proto-Oncogene Proteins c-akt - metabolism; Rapamycin; Rats; Rodents; Signal Transduction; Signaling; Staining; TOR protein; TOR Serine-Threonine Kinases - metabolism; Tumor necrosis factor; Tumor necrosis factor-α
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0071773

Metformin is used in the treatment of Diabetes Mellitus type II and improves liver function in patients with non-alcoholic fatty liver disease (NAFLD). Metformin activates AMP-activated protein kinase (AMPK), the cellular energy sensor that is sensitive to changes in the AMP/ATP-ratio. AMPK is an inhibitor of mammalian target of rapamycin (mTOR). Both AMPK and mTOR are able to modulate cell death. To evaluate the effects of metformin on hepatocyte cell death. Apoptotic cell death was induced in primary rat hepatocytes using either the bile acid glycochenodeoxycholic acid (GCDCA) or TNFα in combination with actinomycin D (actD). AMPK, mTOR and phosphoinositide-3 kinase (PI3K)/Akt were inhibited using pharmacological inhibitors. Apoptosis and necrosis were quantified by caspase activation, acridine orange staining and Sytox green staining respectively. Metformin dose-dependently reduces GCDCA-induced apoptosis, even when added 2 hours after GCDCA, without increasing necrotic cell death. Metformin does not protect against TNFα/ActD-induced apoptosis. The protective effect of metformin is dependent on an intact PI3-kinase/Akt pathway, but does not require AMPK/mTOR-signaling. Metformin does not inhibit NF-κB activation. Metformin protects against bile acid-induced apoptosis and could be considered in the treatment of chronic liver diseases accompanied by inflammation.