Glutathione peroxidase 8 is transcriptionally regulated by HIF? and modulates growth factor signaling in HeLa cells

Bosello-Travain V, Forman HJ, Roveri A, Toppo S, Ursini F, Venerando R, Warnecke C, Zaccarin M, Maiorino M (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Free Radical Biology and Medicine Elsevier

Book Volume: 81

Pages Range: 58-68

DOI: 10.1016/j.freeradbiomed.2014.12.020

Abstract

GPx8 is a mammalian Cys-glutathione peroxidase of the endoplasmic reticulum membrane, involved in protein folding. Its regulation is mostly unknown. We addressed both the functionality of two hypoxia-response elements (HREs) within the promoter, GPx8 HRE1 and GPx8 HRE2, and the GPx8 physiological role. In HeLa cells, treatment with HIF? stabilizers, such as diethyl succinate (DES) or 2-2'-bipyridyl (BP), induces GPx8 expression at both mRNA and protein level. Luciferase activity of pGL3(GPx8wt), containing a fragment of the GPx8 promoter including the two HREs, is also induced by DES/BP or by overexpressing either individual HIF? subunit. Mutating GPx8 HRE1 within pGL3(GPx8wt) resulted in a significantly higher inhibition of luciferase activity than mutating GPx8 HRE2. Electrophoretic mobility-shift assay showed that both HREs exhibit enhanced binding to a nuclear extract from DES/BP-treated cells, with stronger binding by GPx8 HRE1. In DES-treated cells transfected with pGL3(GPx8wt) or mutants thereof, silencing of HIF2?, but not HIF1?, abolishes luciferase activity. Thus GPx8 is a novel HIF target preferentially responding to HIF2? binding at its two novel functional GPx8 HREs, with GPx8 HRE1 playing the major role. Fibroblast growth factor (FGF) treatment increases GPx8 mRNA expression, and reporter gene experiments indicate that induction occurs via HIF. Comparing the effects of depleting GPx8 on the downstream effectors of FGF or insulin signaling revealed that absence of GPx8 results in a 16- or 12-fold increase in phosphorylated ERK1/2 by FGF or insulin treatment, respectively. Furthermore, in GPx8-depleted cells, phosphorylation of AKT by insulin treatment increases 2.5-fold. We suggest that induction of GPx8 expression by HIF slows down proliferative signaling during hypoxia and/or growth stimulation through receptor tyrosine kinases.

Authors with CRIS profile

Christina Warnecke Medizinische Fakultät

Additional Organisation(s)

Department of Medicine 4 – Nephrology and Hypertension

Involved external institutions

University of Padua / Universita degli Studi di Padova IT Italy (IT) University of California, Merced US United States (USA) (US)

How to cite

APA:

Bosello-Travain, V., Forman, H.J., Roveri, A., Toppo, S., Ursini, F., Venerando, R.,... Maiorino, M. (2015). Glutathione peroxidase 8 is transcriptionally regulated by HIF? and modulates growth factor signaling in HeLa cells. Free Radical Biology and Medicine, 81, 58-68. https://dx.doi.org/10.1016/j.freeradbiomed.2014.12.020

MLA:

Bosello-Travain, Valentina, et al. "Glutathione peroxidase 8 is transcriptionally regulated by HIF? and modulates growth factor signaling in HeLa cells." Free Radical Biology and Medicine 81 (2015): 58-68.

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