Both thapsigargin- and tunicamycin-induced endoplasmic reticulum stress increases expression of Hrd1 in IRE1-dependent fashion

ABSTRACT

Objectives: We have investigated the impact of endoplasmic reticulum (ER) stress, which is often implicated in neurodegenerative diseases, on the expression of Hrd1, an E3 ubiquitin ligase that plays a central role in the process of ER-associated degradation (ERAD).

Methods: SH-SY5Y neuroblastoma cells, a frequently used model for studying neurotoxicity in dopaminergic neurons and the mechanisms of neurodegeneration associated with Parkinson’s disease, and parental SK-N-SH cells were studied.

Results: We demonstrate that ER stress, induced by thapsigargin or tunicamycin, correlates with the increased expression of Hrd1 in both SH-SY5Y and SK-N-SH cells. Inhibition of PERK does not significantly suppress the thapsigargin- or tunicamycin-induced expression of Hrd1. Nevertheless, PERK inhibition has a positive effect on the survival of SH-SY5Y cells treated with thapsigargin but not on those treated with tunicamycin. Inhibition of IRE1 associated with the inhibition of XBP1 splicing does not affect the survival of SH-SY5Y cells treated with either thapsigargin or tunicamycin but results in the complete suppression of both the thapsigargin- and tunicamycin-induced expression of Hrd1.

Discussion: Thus, the ER-stress-induced expression of Hrd1 in SH-SY5Y depends on Hrd1 transcription activation, which is a consequence of IRE1 but not of PERK activation.

KEYWORDS:

• Endoplasmic reticulum
• thapsigargin
• tunicamycin
• Hrd1
• neurodegeneration
• Parkinson’s disease (PD)

Acknowledgments

The authors are grateful to Dr. Marian Grendar for his help with statistical analysis, to Dr. Martin Kolisek for helpful suggestions, and to Dr. Theresa Jones for language editing.

Disclosure of interest

The authors report no conflicts of interests.

Additional information

Funding

This work was supported by the Slovak Research and Development Agency under contract no. APVV-16-0033 and by the project Creating a New Diagnostic Algorithm for Selected Cancer Diseases [ITMS: 26220220022] cofinanced from EU sources and the European Regional Development Fund.

Notes on contributors

Katarina Dibdiakova

Katarina Dibdiakova received a PhD degree in Biochemistry from Comenius University in 2018. Her research interests include study of ER-mitochondria interactions. This is her first publication on this topic, otherwise she published in Neurochemical Research and General Physiology and Biophysics.

Simona Saksonova

Simona Saksonova received a PhD degree in Biochemistry from Comenius University in 2018. Her research interests include study of neuroprotective effects of heat shock proteins against different forms of cellular stress. This is her first publication on this topic, otherwise she published in Neurochemical Research and General Physiology and Biophysics.

Ivana Pilchova

Ivana Pilchova is a researcher at BioMedical Centre, Division of Neuroscience, Jessenius Faculty of Medicine, Comenius University, Martin. She received a PhD degree in Biochemistry from Comenius University in 2015. Her research interests include study of molecular mechanisms of death of neuronal cells, with a particular focus on mitochondrial apoptosis and protein quality control associated with associated with different forms of neurodegeneration. Her recent publications appear in wide spectrum of biochemical journals concerned on neuroscience, such as Cellular and Molecular Neurobiology, Neurochemical Research and Journal of Molecular Neuroscience.

Katarina Klacanova

Katarina Klacanova is a researcher at BioMedical Centre, Division of Neuroscience, Jessenius Faculty of Medicine, Comenius University, Martin. She received a PhD degree in Biochemistry from Slovak Technical University in 2009. Her research interests include study of molecular mechanisms of death of neuronal cells, with a particular focus on mitochondrial apoptosis and dynamics associated with ischemic of neurodegeneration. Her recent publications appear in wide spectrum of biochemical journals concerned on neuroscience, such as Cellular and Molecular Neurobiology, Neurochemical Research and Journal of Molecular Neuroscience.

Zuzana Tatarkova

Zuzana Tatarkova is Associate Professor of Biochemistry at Jessenius Faculty of Medicine Comenius University Martin. She received a PhD degree in Biochemistry from Comenius University in 2007. Her research interests include study of mitochondrial dysfunction associated with ischemic injury and ageing. Her recent publications appear in wide spectrum of biochemical Journals concerned on neuroscience, such as Cellular and Molecular Neurobiology, Neurochemical Research, Journal of Molecular Neuroscience, and many others.

Peter Racay

Peter Racay is Professor of Biochemistry at Jessenius Faculty of Medicine Comenius University Martin. He received a PhD degree in Biochemistry from Comenius University in 1998, and has postdoctoral research experience at the University of Fribourg. His research interests include study of molecular mechanisms of death of neuronal cells, with a particular focus on mitochondrial apoptosis, mitochondrial dysfunction, ER-mitochondria interactions and cell stress response associated with different forms of neurodegeneration. His recent publications appear in wide spectrum of biochemical Journals concerned on neuroscience, such as Cellular and Molecular Neurobiology, Neurochemical Research, Journal of Molecular Neuroscience, and many others.