Investigating the Cellular Transcriptomic Response Induced by the Makona Variant of Ebola Virus in Differentiated THP-1 Cells.

Andrew Bosworth,Stuart D Dowall,Stuart Armstrong,Miles W Carroll,Xuan Liu,Roger Hewson,Christine B Bruce,Xiaofeng Dong,Julian A Hiscox,Lisa F P Ng

doi:10.3390/v11111023

Abstract

Recent studies have shown that transcriptomic analysis of blood samples taken from patients with acute Ebola virus disease (EVD) during the 2013–2016 West African outbreak was suggestive that a severe inflammatory response took place in acutely ill patients. The significant knowledge gained from studying the Makona variant, a cause of the largest known EVD outbreak, may be applicable to other species of ebolavirus, and other variants of the Ebola virus (EBOV) species. To investigate the ability of Makona to initiate an inflammatory response in human macrophages and characterise the host response in a similar manner to previously characterised EBOV variants, the human monocytic cell line THP-1 was differentiated into macrophage-like cells and infected with Makona. RNA-Seq and quantitative proteomics were used to identify and quantify host mRNA and protein abundance during infection. Data from infection with Reston virus (RESTV) were used as comparators to investigate changes that may be specific to, or enhanced in, Makona infection in relation to a less pathogenic species of ebolavirus.. This study found demonstrable induction of the inflammatory response, and increase in the activation state of THP-1 macrophages infected with Makona. NFκB and inflammation-associated transcripts displayed significant changes in abundance, reflective of what was observed in human patients during the 2013–2016 EBOV outbreak in West Africa, and demonstrated that transcriptomic changes found in Makona-infected cells were similar to that observed in Reston virus infection and that have been described in previous studies of other variants of EBOV.

Highlights

In the wake of the unexpected emergence of Ebola virus (EBOV) in West Africa [1,2], there has been renewed interest in the fundamental biology of EBOV
EBOV waswith suspected of isolated displaying similar the transcriptomic inducedpathogenesis by the Makona variant compared with thewith
The high degree of pro-inflammatory signalling downstream of the NFκB complex highlights proteins contributing to NFκB activity as interesting targets for future study. These results indicate that NFκB induction may be important for ebolavirus species. The aim of this project was to characterise the host response to the Makona, comparing the profiled transcriptomic and proteomic changes with those induced by infection with the seemingly apathogenic Reston virus (RESTV), helping to identify transcriptomic and proteomic signatures of infection between similar viruses of differing pathogenicity, and contrast observed transcriptomic changes with those seen during infection with other EBOV variants described in the literature

Summary

Introduction

In the wake of the unexpected emergence of Ebola virus (EBOV) in West Africa [1,2], there has been renewed interest in the fundamental biology of EBOV. Advances in next-generation sequencing have allowed the viral lifecycle to be studied at great depth in vitro [3,4], in animal models [5,6], and, most recently, in patients [7]. These studies identified the critical roles of host signalling pathways in the lifecycle of EBOV [4,8,9,10,11]. Infection of macrophages results in a pro-inflammatory phenotype, rapidly increasing levels of tumour necrosis factor (TNF), stimulating immune responses, bystander apoptosis, vascular leakage, and tissue re-modelling [20,22,24,25]

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