Astragalus polysaccharides attenuate PCV2 infection by inhibiting endoplasmic reticulum stress in vivo and in vitro

Hongxia Xue,Shu Hao,Junfa Hu,Fang Gan,Xingxiang Chen,Jing Xu,Gang Qian,Kehe Huang

doi:10.1038/srep40440

Hongxia Xue, Shu Hao + Show 6 more

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https://doi.org/10.1038/srep40440

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Journal: Scientific Reports	Publication Date: Jan 10, 2017
Citations: 20	License type: open-access

Affiliation: Nanjing Agricultural University

Abstract

This study explored the effects of Astragalus polysaccharide (APS) on porcine circovirus type 2 (PCV2) infections and its mechanism in vivo and vitro. First, fifty 2-week-old mice were randomly divided into five groups: a group without PCV2 infection and groups with PCV2 infections at 0, 100, 200 or 400 mg/kg APS treatments. The trial lasted for 28 days. The results showed that APS treatments at 200 and 400 mg/kg reduced the pathological injury of tissues, inhibited PCV2 infection and decreased glucose-regulated protein 78 (GRP78) and GADD153/CHOP gene mRNA and protein expression significantly (P < 0.05). Second, a study on endoplasmic reticulum stress mechanism was carried out in PK15 cells. APS treatments at 15 and 45 μg/mL significantly reduced PCV2 infection and GRP78 mRNA and protein expression (P < 0.05). Tunicamycin supplementation increased GRP78 mRNA and protein expression and significantly attenuated the APS-induced inhibition of PCV2 infection (P < 0.05). Tauroursodeoxycholic acid supplementation decreased GRP78 mRNA and protein expression and significantly inhibited PCV2 infection (P < 0.05). In addition, fifty 2-week-old mice were randomly divided into five groups: Con, PCV2, APS + PCV2, TM + PCV2 and TM + APS + PCV2. The results were similar to those in PK15 cells. Taken together, it could be concluded that APS suppresses PCV2 infection by inhibiting endoplasmic reticulum stress.

Highlights

This study explored the effects of Astragalus polysaccharide (APS) on porcine circovirus type 2 (PCV2) infections and its mechanism in vivo and vitro
Porcine circovirus type 2 (PCV2) infection is known as the main factor in inducing porcine circovirus-associated diseases (PCVADs), which causes huge economic losses in the swine industry[6]
We researched the effects of APS on PCV2 infection by observing the animal weight and pathological changes and detecting the number of PCV2 DNA copies and Cap protein expression (IHC and western blot) in mice

Summary

Introduction

This study explored the effects of Astragalus polysaccharide (APS) on porcine circovirus type 2 (PCV2) infections and its mechanism in vivo and vitro. The results showed that APS treatments at 200 and 400 mg/kg reduced the pathological injury of tissues, inhibited PCV2 infection and decreased glucose-regulated protein 78 (GRP78) and GADD153/CHOP gene mRNA and protein expression significantly (P < 0.05). APS treatments at 15 and 45 μg/mL significantly reduced PCV2 infection and GRP78 mRNA and protein expression (P < 0.05). Tunicamycin supplementation increased GRP78 mRNA and protein expression and significantly attenuated the APS-induced inhibition of PCV2 infection (P < 0.05). A previous study showed that ER stress signalling is important to viral replication by addressing the earliest phase of autophagy induced by ER stress to limit virus production and the survival of dengue-infected cells[33]. Few studies have demonstrated that APS can inhibit PCV2 infection through reducing ER stress

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