Redox homeostasis and posttranslational modifications/activity of phosphatase and tensin homolog in hepatocytes from rats with diet-induced hepatosteatosis

Alisi, Anna; Bruscalupi, Giovannella; Pastore, Anna; Petrini, Stefania; Panera, Nadia; Massimi, Mara; Tozzi, Giulia; Leoni, Silvia; Piemonte, Fiorella; Nobili, Valerio

doi:10.1016/j.jnutbio.2010.11.013

« Previous Next »The Journal of Nutritional Biochemistry
Volume 23, Issue 2 , Pages 169-178, February 2012

Redox homeostasis and posttranslational modifications/activity of phosphatase and tensin homolog in hepatocytes from rats with diet-induced hepatosteatosis☆

Anna Alisi
- Unit of Metabolic and Autoimmune Liver Diseases of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
- Corresponding author. Unit of Metabolic and Autoimmune Liver Diseases of “Bambino Gesù” Children's Hospital and Research Institute, Piazzale S. Onofrio 4, 00165 Rome, Italy. Tel.: +39 06 68592650; fax: +39 06 68592904.
Giovannella Bruscalupi
- Department of Biology and Biotechnology “C. Darwin”^c, “La Sapienza” University, P.le Aldo Moro 5; 00185 Rome, Italy
Anna Pastore
- Laboratory of Biochemistry of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
Stefania Petrini
- Microscopy Unit, of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
Nadia Panera
- Unit of Metabolic and Autoimmune Liver Diseases of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
Mara Massimi
- Department of Basic and Applied Biology, University of L'Aquila, L'Aquila, Italy
Giulia Tozzi
- Neuromuscular and Neurodegenerative Diseases Unit, of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
Silvia Leoni
- Department of Biology and Biotechnology “C. Darwin”^c, “La Sapienza” University, P.le Aldo Moro 5; 00185 Rome, Italy
Fiorella Piemonte
- Neuromuscular and Neurodegenerative Diseases Unit, of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
- These authors have contributed equally to this study.
Valerio Nobili
- Unit of Metabolic and Autoimmune Liver Diseases of Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
- These authors have contributed equally to this study.

Received 28 June 2010; received in revised form 9 November 2010; accepted 16 November 2010. published online 31 March 2011.

Abstract

High-fat and high-carbohydrate diets may predispose to simple steatosis, alone or associated with necroinflammation and fibrosis (steatohepatitis). However, there are few reports about the real effect of these nutrients on hepatocyte redox homeostasis and consequent molecular derangement. Here, we investigated whether different diets would induce oxidative damage in primary rat hepatocytes and thereby affect the activity of phosphatase and tensin homolog (PTEN).

We used Sprague–Dawley rats fed, for 14 weeks, a standard diet (SD), a high-fat/low-carbohydrate diet (HFD-LC), a normal-fat/high-fructose diet (NFD-HF), or a high-fat/high-fructose diet (HFD-HF). Metabolic and histological parameters were analyzed in blood and liver samples, while oxidative stress markers and related posttranscriptional modification of PTEN were analyzed in isolated hepatocytes.

Our results indicate that different dietetic hypercaloric regimens caused liver damage and a significant increase of body and liver weight, as well as elevated plasma levels of alanine aminotransferase, triglycerides and insulin. Hepatocytes from NFD-HF and HFD-HF rats displayed a decrement of cell viability and proliferation rate. Hepatocytes from animals treated with hypercaloric regimens also exhibited oxidative stress greater than SD hepatocytes. Finally, NFD-HF and HFD-HF hepatocytes showed an increased PTEN phosphorylation and decreased PTEN activity, which seem strongly correlated to an increased glutathionylation of the protein.

In conclusion, we demonstrate that fructose-enriched diets cause a tissue and hepatocyte damage that might exacerbate those observed in the presence of high-fat alone and might render, via redox homeostasis imbalance, the hepatocytes more prone to posttranslational modifications and activity alteration of PTEN.

Keywords: Hepatocytes, Hepatosteatosis, Glutathione, Oxidative stress, PTEN