Integrin β3 is required in infection and proliferation of classical swine fever virus.

Weiwei Li,Kai Kang,Yanming Zhang,Kangkang Guo,Wulong Liang,Gang Wang,Lucia R. Languino

doi:10.1371/journal.pone.0110911

Weiwei Li, Kai Kang + Show 5 more

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https://doi.org/10.1371/journal.pone.0110911

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Abstract

Classical Swine Fever (CSF) is a highly infectious fatal pig disease, resulting in huge economic loss to the swine industry. Integrins are membrane-bound signal mediators, expressed on a variety of cell surfaces and are known as receptors or co-receptors for many viruses. However, the role of integrin β3 in CSFV infection is unknown. Here, through quantitive PCR, immunofluorescence (IFC) and immunocytohistochemistry (ICC), we revealed that ST (swine testicles epithelial) cells have a prominent advantage in CSFV proliferation as compared to EC (swine umbilical vein endothelial cell), IEC (swine intestinal epithelial cell) and PK (porcine kidney epithelial) cells. Meanwhile, ST cells had remarkably more integrin β3 expression as compared to EC, IEC and PK cells, which was positively correlated with CSFV infection and proliferation. Integrin β3 was up-regulated post CSFV infection in all the four cell lines, while the CSFV proliferation rate was decreased in integrin β3 function-blocked cells. ShRNA1755 dramatically decreased integrin β3, with a deficiency of 96% at the mRNA level and 80% at the protein level. CSFV proliferation was dramatically reduced in integrin β3 constantly-defected cells (ICDC), with the deficiencies of 92.6%, 99% and 81.7% at 24 h, 48 h and 72 h post CSFV infection, respectively. These results demonstrate that integrin β3 is required in CSFV infection and proliferation, which provide a new insight into the mechanism of CSFV infection.

Highlights

Classical swine fever virus (CSFV) causing the disease of ‘‘classical swine fever (CSF)’’, is a member of the Flaviviradea family which contains Dengue fever virus, West Nile virus (WNV) and Hepatitis C virus
CSFV proliferation amount in cell-culture liquid from ST cells was the highest and continually increased from 24 h to 72 h (Fig. 1C), indicating that CSFV virions secreted from ST cells were much more than that from the other three cell lines
In ST cells, CSFV reached its peak value at 48 h p.i., while it took 72 h for the other three cell lines to reach their peak values. This result suggests that EC, IEC, PK cells have a lower ability in secreting CSFV virions to extracellular matrix than ST cells do (Fig. 1C and 1D)

Summary

Introduction

Classical swine fever virus (CSFV) causing the disease of ‘‘classical swine fever (CSF)’’, is a member of the Flaviviradea family which contains Dengue fever virus, West Nile virus (WNV) and Hepatitis C virus. CSFV leads to huge economic loss in the swine industry as CSF causes problems characterized by high fever, alternating constipation, diarrhea and high mortality [1,2]. Transmission of this virus mainly depends on contact spread, but recent investigations indicated that infected boars could transmit CSFV in semen as well [3,4]. This disease was first identified in USA during a continuous major nationwide epizootics, and was subsequently found in many other countries [5,6]. Considering its rapid speed in spreading across national borders, and the huge socio-economic damage to the porcine industry, CSF was classified as a notifiable disease by OIE [9]

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