title: Acute and Chronic Ethanol Administration Differentially Modulate Hepatic Autophagy and Transcription Factor EB.
abstract: BACKGROUND
  Chronic ethanol (EtOH) consumption decelerates the catabolism of long-lived proteins, indicating that it slows hepatic macroautophagy (hereafter called autophagy) a crucial lysosomal catabolic pathway in most eukaryotic cells. Autophagy and lysosome biogenesis are linked. Both are regulated by the transcription factor EB (TFEB). Here, we tested whether TFEB can be used as a singular indicator of autophagic activity, by quantifying its nuclear content in livers of mice subjected to acute and chronic EtOH administration. We correlated nuclear TFEB to specific indices of autophagy.
  
  
  METHODS
  In acute experiments, we gavaged GFP-LC3(tg) mice with a single dose of EtOH or with phosphate buffered saline (PBS). We fed mice chronically by feeding them control or EtOH liquid diets.
  
  
  RESULTS
  Compared with PBS-gavaged controls, livers of EtOH-gavaged mice exhibited greater autophagosome (AV) numbers, a higher incidence of AV-lysosome co-localization, and elevated levels of free GFP, all indicating enhanced autophagy, which correlated with a higher nuclear content of TFEB. Compared with pair-fed controls, livers of EtOH-fed mice exhibited higher AV numbers, but had lower lysosome numbers, lower AV-lysosome co-localization, higher P62/SQSTM1 levels, and lower free GFP levels. The latter findings correlated with lower nuclear TFEB levels in EtOH-fed mice. Thus, enhanced autophagy after acute EtOH gavage correlated with a higher nuclear TFEB content. Conversely, chronic EtOH feeding inhibited hepatic autophagy, associated with a lower nuclear TFEB content.
  
  
  CONCLUSIONS
  Our findings suggest that the effect of acute EtOH gavage on hepatic autophagy differs significantly from that after chronic EtOH feeding. Each regimen distinctly affects TFEB localization, which in turn, regulates hepatic autophagy and lysosome biogenesis.
authors.affiliation: Liver Study Unit, Department of Veterans Affairs, VA Nebraska-Western Iowa Health Care System (NWIHCS), Omaha, Nebraska.|Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Thomes
authors.affiliation: Liver Study Unit, Department of Veterans Affairs, VA Nebraska-Western Iowa Health Care System (NWIHCS), Omaha, Nebraska.|Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Casey S
authors.initials: CS
authors.lastname: Trambly
authors.affiliation: Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Howard S
authors.initials: HS
authors.lastname: Fox
authors.affiliation: Liver Study Unit, Department of Veterans Affairs, VA Nebraska-Western Iowa Health Care System (NWIHCS), Omaha, Nebraska.|Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.|Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Dean J
authors.initials: DJ
authors.lastname: Tuma
authors.affiliation: Liver Study Unit, Department of Veterans Affairs, VA Nebraska-Western Iowa Health Care System (NWIHCS), Omaha, Nebraska.|Department of Internal Medicine, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.|Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.|Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska.|The Center for Environmental Health and Toxicology, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Donohue
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects* / Q000502:physiology; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism*; D000431:Ethanol / Q000008:administration & dosage* / Q000633:toxicity*; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C484068:Tcfeb protein, mouse; D000431:Ethanol
keywords: Autophagosome; Lysosome; Proteopathy; Steatosis; Transcription Factor EB