The human vascular endothelial cell line HUV-EC-C harbors the integrated HHV-6B genome which remains stable in long term culture

Setsuko Shioda,Yasuko Mori,Arihiro Kohara,Midori Ozawa,Motonobu Satoh,Ken Watanabe,Norio Shimizu,Fumio Kasai,Yousuke Kameoka,Huamin Tang,Noriko Hirayama

doi:10.1007/s10616-017-0119-y

Abstract

Human herpes virus 6 (HHV-6) is a common human pathogen that is most often detected in hematopoietic cells. Although human cells harboring chromosomally integrated HHV-6 can be generated in vitro, the availability of such cell lines originating from in vivo tissues is limited. In this study, chromosomally integrated HHV-6B has been identified in a human vascular endothelial cell line, HUV-EC-C (IFO50271), derived from normal umbilical cord tissue. Sequence analysis revealed that the viral genome was similar to the HHV-6B HST strain. FISH analysis using a HHV-6 DNA probe showed one signal in each cell, detected at the distal end of the long arm of chromosome 9. This was consistent with a digital PCR assay, validating one copy of the viral DNA. Because exposure of HUV-EC-C to chemicals did not cause viral reactivation, long term cell culture of HUV-EC-C was carried out to assess the stability of viral integration. The growth rate was altered depending on passage numbers, and morphology also changed during culture. SNP microarray profiles showed some differences between low and high passages, implying that the HUV-EC-C genome had changed during culture. However, no detectable change was observed in chromosome 9, where HHV-6B integration and the viral copy number remained unchanged. Our results suggest that integrated HHV-6B is stable in HUV-EC-C despite genome instability.

Highlights

A variety of human cell lines have been established from cancerous or normal cells obtained from peripheral blood or solid organs (Geraghty et al 2014)
Our results suggest that integrated HHV-6B is stable in HUV-ECC despite genome instability
The copy number of human herpesvirus 6 (HHV-6) in HUV-EC-C cells was examined by the QuantStudio 3D Digital PCR System (Thermo Fisher Scientific)

Summary

Introduction

A variety of human cell lines have been established from cancerous or normal cells obtained from peripheral blood or solid organs (Geraghty et al 2014). Our viral test based on PCR includes human herpesvirus 6 (HHV-6), known as a cause of roseola (Yamanishi et al 1988). After initial infection in infants, HHV-6 remains latent mainly in lymphocytes and is often found in saliva (Luppi et al 1993). This persistent infection has the potential of reactivation, which is most common during pregnancy and is associated with fatigue. Because the viral genome encodes telomere repeats at the both ends, this integration occurs via homologous recombination (Arbuckle et al 2010). There is little human cell line established from HHV-6 integrated cells and research into HHV-6 using cell lines has so far been limited

Methods

Results

Conclusion