S-adenosyl-methionine decreases ethanol-induced apoptosis in primary hepatocyte cultures by a c-Jun N-terminal kinase activity-independent mechanism

• Published in: World journal of gastroenterology : WJG Vol. 12; no. 12; pp. 1895 - 1904
• Main Authors: Cabrales-Romero, Maria del Pilar, Márquez-Rosado, Lucrecia, Fattel-Fazenda, Samia, Trejo-Solís, Cristina, Arce-Popoca, Evelia, Alemán-Lazarini, Leticia, Villa-Treviño, Saúl
• Format: Journal Article
• Language: English
• Published: United States Department of Cell Biology, Centro de Investigación y Estudios Avanzados IPN, Av. IPN No. 2508 México DF, México%Department of Neuroimmunology, Instituto Nacional de Neurología y Neurocirugía MVS, Insurgentes Sur 3877, Col La Fama DF México%Centro de Investigación y Estudios Avanzados IPN, Av. IPN No. 2508 México DF CP 07360, México 28.03.2006; Baishideng Publishing Group Co., Limited
• Subjects: Animals; Anthracenes - pharmacology; Apoptosis - drug effects; Apoptosis - physiology; Basic Research; BH3 Interacting Domain Death Agonist Protein - metabolism; Caspase 3; Caspases - metabolism; Cells, Cultured; Cytochromes c - metabolism; Ethanol - pharmacology; Glutathione - metabolism; Hepatocytes - drug effects; Hepatocytes - physiology; JNK Mitogen-Activated Protein Kinases - antagonists & inhibitors; JNK Mitogen-Activated Protein Kinases - physiology; Male; Mitochondria; Rats; Rats, Inbred F344; Reactive Oxygen Species - metabolism; S-Adenosylmethionine - pharmacology; Signal Transduction - drug effects; Signal Transduction - physiology; c-Jun N-terminal kinase; Reactive oxygen species; Bid; Alcoholic liver disease; Apoptosis; SP600125; S-Adenosyl methionine
• DOI: 10.3748/wjg.v12.i12.1895
• ISSN: 1007-9327

To determine the role of c-Jun N-terminal kinase (JNK) activity in ethanol-induced apoptosis and the modulation of this signaling cascade by S-Adenosyl-methionine (AdoMet). Primary hepatocyte cultures were pretreated with 100 micromol/L SP600125, a selective JNK inhibitor, 1 mL/L DMSO or 4 mmol/L AdoMet and then exposed to 100 mmo/L ethanol. Hepatocyte apoptosis was determined by the TUNEL and DNA ladder assays. JNK activity and its inhibition by SP600125 and AdoMet were determined by Western blot analysis of c-jun phosphorylation and Bid fragmentation. SP600125 and AdoMet effects on the apoptotic signaling pathway were determined by Western blot analysis of cytochrome c release and pro-caspase 3 fragmentation. The AdoMet effect on glutathione levels was measured by Ellman's method and reactive oxygen species (ROS) generation by cell cytometry. The exposure of hepatocytes to ethanol induced JNK activation, c-jun phosphorylation, Bid fragmentation, cytochrome c release and pro-caspase 3 cleavage; these effects were diminished by SP600125, and caused a significant decrease in ethanol-induced apoptosis (P< 0.05). AdoMet exerted an antioxidant effect maintaining glutathione levels and decreasing ROS generation, without a significant effect on JNK activity, and prevented cytochrome c release and pro-caspase 3 cleavage. The JNK signaling cascade is a key component of the proapoptotic signaling pathway induced by ethanol. JNK activation may be independent from ROS generation, since AdoMet which exerted antioxidant properties did not have a significant effect on JNK activity. JNK pathway modulator agents and AdoMet may be components of promising therapies for alcoholic liver disease (ALD) treatment.