William Austin J Guild

Conference 2023 Live Talk

Talk title

Identification of putative ERV binding proteins in the vaginal epithelium using mass spectrometry

Authors and Affiliations

W. Austin Guild1, Jason Rogalski2, Maria Tokuyama1

1. Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
2. Centre for Blood Research and Life Sciences Institute, University of British Columbia, Vancouver, Canada

Abstract

Background

Herpes Simplex Virus 2 (HSV-2) is endemic in many countries and estimated to infect 491 million people worldwide. Individuals with HSV-2 experience a life-long infection with reoccurring uncomfortable symptoms, as well as an increased risk of co-infection with other viruses such as hepatitis C virus and HIV. There is no cure or vaccine for HSV-2, and there are limited treatment options. Therefore, new areas of research to combat HSV-2 must be explored to aid in the development of new therapeutics. An area of research that has not been well studied is the potential of endogenous retroviruses (ERVs) to protect the host against viral pathogens. ERVs are ancient viral sequences that make up 8% of the human genome and originated from retroviral infection of non-human primates over 40 million years ago. Our lab has shown that replication competent ERVs are capable of protecting mice against disease caused by vaginal HSV-2 infection through modulating cellular processes. However, the exact mechanism of this protection is still not defined. I hypothesize that direct interaction between ERVs and the vaginal epithelium induces antiviral immunity. My objective is to identify ERV-interacting partners in the vaginal tissue and determine the mechanism by which these interactions provide protection against HSV-2.

Methods

We performed a co-immunoprecipitation (co-IP) assay with whole vaginal tissue lysates from C57BL/6N wild-type mice, purified ERVs isolated from TLR7-deficient mice, and anti-ERV envelope antibody 83A25. The eluates were run on a gel and stained with Coomassie blue. We then analyzed the eluates using liquid chromatography mass spectrometry.

Results

Our co-IP revealed putative ERV-binding partners in the mouse vaginal tissues that are approximately 70 kDa. Mass spectrometry analysis of the 70 kDa band revealed many putative ERV binding partners. The top protein hits identified included albumin, annexin A6, heat shock cognate protein, actin, myoferlin and lactadherin. Many of these proteins are involved in the transcytosis pathway, suggesting that infectious ERVs may utilize the transcytosis pathway as a possible mechanism to enter the vaginal epithelium to mediate protection against HSV-2.

Conclusions

We have previously shown that ERVs enhance immunity against vaginal HSV-2 disease in mice. Our recent data revealed that ERVs can bind to proteins in mouse vaginal tissue that are involved in the transcytosis pathway, providing further insights into how ERVs may modulate the vaginal mucosa to boost protection against HSV-2. Better understanding of the mechanism by which ERVs enhance protection against HSV-2 can contribute to designing new therapeutics in the future.