Combination of chronic stress with fructose diet increases AMP-activated protein kinase phosphorylation and affects agouti-related protein and proopiomelanocortin expression in the hypothalamus of male Wistar rats

Abdulbaset Zidane Shirif; Sanja Kovačević; Biljana Bursać; Iva Lakić; Nataša Veličković; Tanja Jevdjovic; Ana Djordjevic

doi:10.18388/abp.2020_6075

Abdulbaset Zidane Shirif Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
Sanja Kovačević Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
Biljana Bursać Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
Iva Lakić Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
Nataša Veličković Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
Tanja Jevdjovic Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
Ana Djordjevic Institute for Biological Research "Sinisa Stankovic" - National Institute of Republic of Serbia, University of Belgrade https://orcid.org/0000-0002-7042-1631

DOI: https://doi.org/10.18388/abp.2020_6075

Abstract

Appetite regulation in the hypothalamus is dependent on hormonal signals from the periphery, such as insulin and leptin, and can be modulated by both sugar-rich diet and stress. Our aim was to explore the effects of 9-week feeding with 20% fructose solution combined with 4-week chronic unpredictable stress, on appetite-regulating neuropeptides and modulatory role of leptin and insulin signalling in the hypothalamus of male Wistar rats. Energy intake, body mass and adiposity, as well as circulatory leptin and insulin concentrations were assessed. Hypothalamic insulin signalling was analysed at the level of glucose transporters, as well as at the protein level and phosphorylation of insulin receptor, insulin receptor supstrate-1, Akt and ERK. Phosphorylation of AMP-activated protein kinase (AMPK), level of protein tyrosine phosphatase 1B (PTP1B) and expression of leptin receptor (ObRb) and suppressor of cytokine signalling 3 (SOCS3) were also analysed, together with the expression of orexigenic agouti-related protein (AgRP) and anorexigenic proopiomelanocortin (POMC) neuropeptides. The results revealed that stress decreased body mass and adiposity, blood leptin level and expression of ObRb, SOCS3 and POMC, while combination with fructose diet led to marked increase of AgRP, associated with AMPK phosphorylation despite increased plasma insulin. Reduced Akt, enhanced ERK activity and elevated PTP1B were also observed in the hypothalamus of these animals. In conclusion, our results showed that joint effects of fructose diet and stress are more deleterious than the separate ones, since inappropriate appetite control in the hypothalamus may provide a setting for the disturbed energy homeostasis in the long run.

Author Biographies

Abdulbaset Zidane Shirif, Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Abdulbaset Zidane Shirif is a PhD student in the Department of Biochemistry, at the Institute for Biological Research “Siniša Stanković”- National Institute of Republic of Serbia, University of Belgrade, Serbia. His research is mainly focused on the molecular and biochemical mechanisms through which fructose overload and/or chronic stress exposure elicit metabolic disorders in skeletal muscle and hypothalamus leading to obesity, insulin resistance and cardiovascular disease.

Sanja Kovačević, Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Dr. Sanja Kovacevic is Research Associate at the University of Belgrade, Institute for Biological Research “Siniša Stankovic”- National Institute of Republic of Serbia (IBISS). She received her BSc and PhD degrees from the University of Belgrade, Serbia. Her post-doctoral training was at the Laboratory for Biochemistry at the Institute for Biological Research “Siniša Stankovic”. From 2014 she is a member of Danish Diabetes and member of Serbian Society for Molecular Biology from 2015. She received permanent position at IBISS in 2017. Presently, she is exploring molecular mechanisms and organ crosstalk leading to development of metabolic syndrome and type 2 diabetes in both males and females, as a consequence of modern lifestyle that is characterized by daily exposure to stress and an increased intake of caloric food rich in fructose.

Biljana Bursać, Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Dr. Biljana Bursać is Research Associate at the University of Belgrade, Institute for Biological Research “Siniša Stankovic”- National Institute of Republic of Serbia. She received her BSc and PhD degrees from the University of Belgrade, Serbia. She is currently at post-doctoral training at Institut de biochimie et genetique cellulaires, University of Bordeaux, Bordeaux, France. Her scientific interest was mainly in the elucidation of the role of glucocorticoids in lipid metabolism perturbations in different tissues of rodents exposed to fructose diet and chronic stress. She is presently exploring the mechanisms by which hydrogen sulfide could be used for health span and lifespan extension.

Iva Lakić, Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia

Dr. Iva Lakić is Assistant Professor at the University of Belgrade, Faculty of Biology. She received her BSc and PhD degrees from the University of Belgrade, Serbia. She gained her PhD degree studying the effects of psychosocial stressors on HPA axis. Her post-doctoral training was at the laboratory for physiology at the Faculty of Biology. She is presently working on research project focused on the energy homeostasis and insulin signaling in hypothalamus.

Nataša Veličković, Department of Biochemistry, Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia

Dr. Nataša Veličković is Principal Research Fellow at the University of Belgrade, Institute for Biological Research “Siniša Stankovic”- National Institute of Republic of Serbia (IBISS). She obtained her BSc and PhD degrees in Molecular Biology and Physiology at the Faculty of Biology, University of Belgrade, Serbia. From 1996-2010 she was employed as PhD student at the Institute for Nuclear Sciences Vinca, while currently she is positioned as post-doctoral researcher at Department of Biochemistry IBISS. From 2013-2017 she participated in the SCOPES JRP project granted by Swiss National Science Foundation (Grant No IZ73ZO_152331) Her research interests are mainly in the field of molecular endocrinology and radiobiology, and lately in the field of nutritional biochemistry.

Tanja Jevdjovic, Department for Comparative Physiology and Ecophysiology, Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia

Dr. Tanja Jevdjovic is an Assistant Professor at the University of Belgrade, Faculty of Biology, Serbia. She received her BSc degree from the University of Belgrade and her PhD degree from the University of Zurich, Switzerland. Her post-doctoral training was at the Division for Neuroendocrinology at the Institute of Anatomy, University of Zurich, Switzerland and at the Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands. Her current research focuses on investigating effects of short term food deprivation on insulin signaling in the hypothalamus.