Chronic ethanol consumption enhances sensitivity to Ca2+-mediated opening of the mitochondrial permeability transition pore and increases cyclophilin D in liver

• Published in: American journal of physiology: Gastrointestinal and liver physiology 2010-10, Vol.299 (4), p.G954-G966
• Main Authors: King, Adrienne L, Swain, Telisha M, Dickinson, Dale A, Lesort, Mathieu J, Bailey, Shannon M
• Format: Article
• Language: English
• Subjects: Liver and Biliary Tract
• ISSN: 1522-1547; 0193-1857; 1522-1547
• DOI: 10.1152/ajpgi.00246.2010

Chronic ethanol consumption increases mitochondrial oxidative stress and sensitivity to form the mitochondrial permeability transition pore (MPTP). The mechanism responsible for increased MPTP sensitivity in ethanol-exposed mitochondria and its relation to mitochondrial Ca2+ handling is unknown. Herein, we investigated whether increased sensitivity to MPTP induction in liver mitochondria from ethanol-fed rats compared with controls is related to an ethanol-dependent change in mitochondrial Ca2+ accumulation. Liver mitochondria were isolated from control and ethanol-fed rats, and Ca2+-mediated induction of the MPTP and mitochondrial Ca2+ retention capacity were measured. Levels of proposed MPTP proteins as well as select pro- and antiapoptotic proteins were measured along with gene expression. We observed increased steatosis and TUNEL-stained nuclei in liver of ethanol-fed rats compared with controls. Liver mitochondria from ethanol-fed rats had increased levels of proapoptotic Bax protein and reduced Ca2+ retention capacity compared with control mitochondria. We observed increased cyclophilin D (Cyp D) gene expression in liver and protein in mitochondria from ethanol-fed animals compared with controls, whereas there was no change in the adenine nucleotide translocase and voltage-dependent anion channel. Together, these results suggest that enhanced sensitivity to Ca2+-mediated MPTP induction may be due, in part, to higher Cyp D levels in liver mitochondria from ethanol-fed rats. Therefore, therapeutic strategies aimed at normalizing Cyp D levels may be beneficial in preventing ethanol-dependent mitochondrial dysfunction and liver injury.