Direct Interaction Between CD163 N-Terminal Domain and MYH9 C-Terminal Domain Contributes to Porcine Reproductive and Respiratory Syndrome Virus Internalization by Permissive Cells.

Lu Zhang,Biyun Xue,Gaopeng Hou,Yuchen Nan,En-Min Zhou,Julian A Hiscox,Chunyan Wu,James P Stewart,Jingfei Wang,Liangliang Li,Qin Zhao,Kuokuo Li

doi:10.3389/fmicb.2019.01815

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) has a highly restricted tropism for cells of the monocyte-macrophage lineage, including porcine alveolar macrophages (PAMs). PRRSV entry into permissive cells involves several mediators in addition to two required host cell receptors, CD163 and MYH9. It is unknown whether CD163 directly interacts and/or cooperates with MYH9 to facilitate PRRSV infection. In this study, CD163 and MYH9 were co-immunoprecipitated from PAMs regardless of PRRSV infection status. Further truncation analysis indicated that the CD163 N-terminal region, containing scavenger receptor cysteine-rich domains 1 to 4 (SRCR1-4), directly interacts with the MYH9 C-terminal domain region without involvement of other adaptor proteins. Meanwhile, non-permissive HEK293T cells that stably expressed truncated swine CD163 SRCR1-4 domain did not support virus attachment. However, virus attachment to cells stably expressing SRCR5-CT domain was demonstrated to occur without appreciable virus internalization. The involvement of the SRCR1-4 domain in virus internalization was further demonstrated by the fact that incubation of recombinant SRCR1-4 protein with PAMs abolished subsequent virus internalization by permissive cells. These results demonstrated that CD163 SRCR1-4 interacts with the MYH9 C–terminal domain to facilitate PRRSV virion internalization in permissive cells, thus expanding our understanding of PRRSV cell-invasion mechanisms.

Highlights

Porcine reproductive and respiratory syndrome (PRRS), an infectious disease that first emerged in the United States in 1987, currently causes huge economic losses to the swine industry worldwide (Nan et al, 2017)
Co-immunoprecipitation Assay (Co-IP) was conducted using porcine alveolar macrophages (PAMs) extracts to examine the interaction between CD163 and myosin heavy chain 9 (MYH9) in the presence or absence of PRRS virus (PRRSV) infection
The results showed that both proteins immunoprecipitated (IP) together either from uninfected PAMs (Figures 1A,B) or PAMs infected with PRRSV-2 JXA1 strain (Figures 1C,D), demonstrating that CD163 and MYH9 interacted in PAMs regardless of PRRSV infection status

Summary

Introduction

Porcine reproductive and respiratory syndrome (PRRS), an infectious disease that first emerged in the United States in 1987, currently causes huge economic losses to the swine industry worldwide (Nan et al, 2017). The clinical symptoms of PRRS include reproductive failure in pregnant sows and respiratory disorders in young piglets (Snijder et al, 2013). CD163-MYH9 Interaction for PRRSV Infection of PRRS, is a single-stranded positive-sense RNA virus (Das et al, 2010). PRRSV has a highly restricted cell tropism whereby it infects cells of the monocyte-macrophage lineage (Van Breedam et al, 2010) that including porcine alveolar macrophages (PAMs), the primary target of PRRSV infection in vivo (Rossow et al, 1995; Qi et al, 2017). African green monkey kidney cell line MA104 and its sub-clone MARC-145 are susceptible to PRRSV infection and have been frequently used in PRRSV studies in vitro (Kim et al, 1993; Song et al, 2018)

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Discussion

Conclusion