Comparative Genomics, Infectivity and Cytopathogenicity of American Isolates of Zika Virus that Developed Persistent Infections in Human Embryonic Kidney (HEK293) Cells.

Hebing Liu,Shyh-Ching Lo,Guo-Chiuan Hung,Hsiao-Mei Liao,Bingjie Li,Shien Tsai

doi:10.3390/ijms20123035

Hebing Liu, Shyh-Ching Lo + Show 4 more

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https://doi.org/10.3390/ijms20123035

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Abstract

Zika virus (ZIKV) transmission can cause serious fetal neurological abnormalities. ZIKV persistence in various human cells and tissues can serve as infectious reservoirs and post serious threats to public health. The human embryonic kidney (HEK293) cell line with known neuronal developmental properties was readily infected by ZIKV in a strain-dependent fashion. Significant cytopathic effect in HEK293 cells infected by the prototype MR 766 strain of ZIKV resulted in complete loss of cells, while small numbers of HEK293 cells infected by contemporary ZIKV isolates (PRV or FLR strain) continued to survive and regrow to confluency in the culture around two months after initial infection. Most, if not all, of the cells in the two resulting persistently ZIKV-infected HEK293 cell lines tested positive for ZIKV antigen. Compared to HEK293 control cells, the persistently ZIKV-infected HEK293 cells had slower growth rates with some cells undergoing apoptosis in culture. The “persistent ZIKVs” produced constitutively by both PRV and FLR strains ZIKV-infected HEK293 cells had significantly attenuated cell infectivity and/or cytopathogenicity. Comparative genome sequence analyses between the persistent ZIKVs and the original inoculum ZIKVs showed no clonal selection with specific gene mutations in the prolonged process of establishing persistently PRV strain ZIKV-infected HEK293 cells; while selection of ZIKV subclones with mutations in the envelope, protein pr and multiple NS genes was evident in developing persistently FLR strain ZIKV-infected HEK293 cell line. Our study provides molecular insights into the complex interplays of ZIKV and human host cells in establishing ZIKV persistence.

Highlights

The emergence of Zika virus (ZIKV) in 1947 from Rhesus monkey in the Zika forest of Uganda has resulted in new challenges to global public health
Previous studies conducted by our laboratory showed that the prototype MR 766 strain ZIKV initially developed only a low-grade infection at a slow rate in the human monocytic/histiocytic U937 cell line without causing cytopathic effects (CPE) changes or cytolysis could lead to ZIKV persistency
Our current study revealed the American isolates including the PRVABC59 strain (PRV) and FLR ZIKV strains failed to infect the human hematopoietic U937 cell line

Summary

Introduction

The emergence of Zika virus (ZIKV) in 1947 from Rhesus monkey in the Zika forest of Uganda has resulted in new challenges to global public health. Viral persistence in the infected hosts has long been recognized as a common theme in flavivirus biology. The transmission of West Nile Virus (WNV), another flavivirus, from WNV-infected organ donors who were no longer viremic during blood testing to recipients through organ transplantation is well-documented [5,6]. To effectively prevent ZIKV transmission through transfusion of infected blood and through transplantation of infected organs or tissues, a better understanding of the human cells that could potentially be harboring the infectious virus and serving continuously as a ZIKV reservoir over a prolonged time is needed. The dynamic process of ZIKV clonal selection with specific gene mutations during persistent viral infection and the adaptive mechanisms of human host cells that confer ZIKV persistence will need to be further explored

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