Νew Publication by researchers of the HPI for the Dengue virus

Dengue virus manipulates hypoxia response and oxygen-dependent metabolic reprogramming for efficient viral replication.

Τhe research group of the molecular virologist Dr Niki Vassilaki in the Hellenic Pasteur Institute in collaboration with distinguished scientists from Greece and abroad published in the open access journal Cells 2018, 7(12), 241; https://doi.org/10.3390/cells7120241
a manuscript with title: The Role of Tissue Oxygen Tension in Dengue Virus Replication. https://www.mdpi.com/2073-4409/7/12/241 that contributes important information to the understanding of the infection mechanisms by the Dengue virus.

The authors of the manuscript and their affiliations are:
Efseveia Frakolaki 1, Panagiota Kaimou 1, Maria Moraiti 1, Katerina I. Kalliampakou 1, Kalliopi Karampetsou 2, Eleni Dotsika 2, Panagiotis Liakos 3, Dido Vassilacopoulou 4, Penelope Mavromara 5, Ralf Bartenschlager 6,7 and Niki Vassilaki 1,*

1Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece
2Laboratory of Cellular Immunology, Hellenic Pasteur Institute, 11521 Athens, Greece
3Laboratory of Biochemistry, School of Medicine, University of Thessaly, 41500 Larissa, Greece
4Section of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece
5Laboratory of Biochemistry and Molecular Virology, Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Thrace, Greece
6Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany
7German Center for Infection Research, Heidelberg partner site, 69120 Heidelberg, Germany
*Author to whom correspondence should be addressed.

Abstract
Low oxygen tension exerts a profound effect on the replication of several DNA and RNA viruses. In vitro propagation of Dengue virus (DENV) has been conventionally studied under atmospheric oxygen levels despite that in vivo, the tissue microenvironment is hypoxic. Here, we compared the efficiency of DENV replication in liver cells, monocytes, and epithelial cells under hypoxic and normoxic conditions, investigated the ability of DENV to induce a hypoxia response and metabolic reprogramming and determined the underlying molecular mechanism. In DENV-infected cells, hypoxia had no effect on virus entry and RNA translation, but enhanced RNA replication. Overexpression and silencing approaches as well as chemical inhibition and energy substrate exchanging experiments showed that hypoxia-mediated enhancement of DENV replication depends on the activation of the key metabolic regulators hypoxia-inducible factors 1α/2α (HIF-1α/2α) and the serine/threonine kinase AKT. Enhanced RNA replication correlates directly with an increase in anaerobic glycolysis producing elevated ATP levels. Additionally, DENV activates HIF and anaerobic glycolysis markers. Finally, reactive oxygen species were shown to contribute, at least in part through HIF, both to the hypoxia-mediated increase of DENV replication and to virus-induced hypoxic reprogramming. These suggest that DENV manipulates hypoxia response and oxygen-dependent metabolic reprogramming for efficient viral replication.