Full Text:   <1302>

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CLC number: S852.65+9.2

On-line Access: 2020-07-07

Received: 2019-11-23

Revision Accepted: 2020-02-16

Crosschecked: 2020-06-05

Cited: 0

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Citations:  Bibtex RefMan EndNote GB/T7714


Wei-huan Fang


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Journal of Zhejiang University SCIENCE B 2020 Vol.21 No.7 P.560-570


Porcine circovirus 3 capsid protein induces autophagy in HEK293T cells by inhibiting phosphorylation of the mammalian target of rapamycin

Author(s):  Shi-chao Geng, Xiao-liang Li, Wei-huan Fang

Affiliation(s):  Institute of Preventive Veterinary Medicine, Zhejiang University, Hangzhou 310058, China; more

Corresponding email(s):   whfang@zju.edu.cn

Key Words:  Porcine circovirus 3 (PCV3), Capsid (Cap) protein, Autophagy

Shi-chao Geng, Xiao-liang Li, Wei-huan Fang. Porcine circovirus 3 capsid protein induces autophagy in HEK293T cells by inhibiting phosphorylation of the mammalian target of rapamycin[J]. Journal of Zhejiang University Science B, 2020, 21(7): 560-570.

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publisher="Zhejiang University Press & Springer",

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%T Porcine circovirus 3 capsid protein induces autophagy in HEK293T cells by inhibiting phosphorylation of the mammalian target of rapamycin
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T1 - Porcine circovirus 3 capsid protein induces autophagy in HEK293T cells by inhibiting phosphorylation of the mammalian target of rapamycin
A1 - Shi-chao Geng
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SP - 560
EP - 570
%@ 1673-1581
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PB - Zhejiang University Press & Springer
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DOI - 10.1631/jzus.B1900657

porcine circovirus 3 (PCV3) has been detected in major pig-producing countries around the world since its first report in the US in 2016. Most current studies have focused on epidemiological investigations and detection methods of PCV3 because of lack of live virus strains for research on its pathogenesis in porcine cells or even in pigs. We constructed a recombinant plasmid pCMV-Cap carrying the PCV3 orf2 gene to investigate the effects of capsid (Cap) protein expression on autophagic response in human embryonic kidney cell line 293T (HEK293T). We demonstrate that PCV3 Cap protein induced complete autophagy shown as formation of autophagosomes and autophagosome-like vesicles as well as LC3-II conversion from LC3-I via inhibiting phosphorylation of the mammalian target of rapamycin (mTOR) in HEK293T cells. The ubiquitin–proteasome pathway is also involved in the autophagy process. These findings provide insight for further exploration of PCV3 pathogenetic mechanisms in porcine cells.




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[1]Allan GM, McNeilly F, Kennedy S, et al., 1998. Isolation of porcine circovirus-like viruses from pigs with a wasting disease in the USA and Europe. J Vet Diagn Invest, 10(1):3-10.

[2]Bjørkøy G, Lamark T, Brech A, et al., 2005. p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on Huntingtin-induced cell death. J Cell Biol, 171(4):603-614.

[3]Díaz-Troya S, Pérez-Pérez ME, Florencio FJ, et al., 2008. The role of TOR in autophagy regulation from yeast to plants and mammals. Autophagy, 4(7):851-865.

[4]Ding QX, Dimayuga E, Markesbery WR, et al., 2006. Proteasome inhibition induces reversible impairments in protein synthesis. FASEB J, 20(8):1055-1063.

[5]Dossou AS, Basu A, 2019. The emerging roles of mTORC1 in macromanaging autophagy. Cancers (Basel), 11(10):1422.

[6]Ellis J, 2014. Porcine circovirus: a historical perspective. Vet Pathol, 51(2):315-327.

[7]Faccini S, Barbieri I, Gilioli A, et al., 2017. Detection and genetic characterization of porcine circovirus type 3 in Italy. Transbound Emerg Dis, 64(6):1661-1664.

[8]Franzo G, Legnardi M, Hjulsager CK, et al., 2018. Full-genome sequencing of porcine circovirus 3 field strains from Denmark, Italy and Spain demonstrates a high within-Europe genetic heterogeneity. Transbound Emerg Dis, 65(3):602-606.

[9]Gao ZH, Gammoh N, Wong PM, et al., 2010. Processing of autophagic protein LC3 by the 20S proteasome. Autophagy, 6(1):126-137.

[10]Han YH, Moon HJ, You BR, et al., 2009. The effect of MG132, a proteasome inhibitor on HeLa cells in relation to cell growth, reactive oxygen species and GSH. Oncol Rep, 22(1):215-221.

[11]Hara T, Nakamura K, Matsui M, et al., 2006. Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice. Nature, 441(7095):885-889.

[12]Harhouri K, Navarro C, Depetris D, et al., 2017. MG132-induced progerin clearance is mediated by autophagy activation and splicing regulation. EMBO Mol Med, 9(9):1294-1313.


[14]Hayashi S, Ohshima Y, Furuya Y, et al., 2018. First detection of porcine circovirus type 3 in Japan. J Vet Med Sci, 80(9):1468-1472.

[15]He CC, Klionsky DJ, 2009. Regulation mechanisms and signaling pathways of autophagy. Annu Rev Genet, 43(1):67-93.

[16]He K, Xin YP, Shan Y, et al., 2019. Phosphorylation residue T175 in RsbR protein is required for efficient induction of sigma B factor and survival of Listeria monocytogenes under acidic stress. J Zhejiang Univ-Sci B (Biomed & Biotechnol), 20(8):660-669.

[17]Hernaez B, Cabezas M, Muñoz-Moreno R, et al., 2013. A179L, a new viral Bcl2 homolog targeting Beclin 1 autophagy related protein. Curr Mol Med, 13(2):305-316.

[18]Ji MM, Lee JM, Mon H, et al., 2016. Proteasome inhibitor MG132 impairs autophagic flux through compromising formation of autophagosomes in Bombyx cells. Biochem Biophys Res Commun, 479(4):690-696.

[19]Jiang HJ, Wang D, Wang J, et al., 2019. Induction of porcine dermatitis and nephropathy syndrome in piglets by infection with porcine circovirus type 3. J Virol, 93(4):e02045-18.

[20]Jiang HY, Wek RC, 2005. Phosphorylation of the α-subunit of the eukaryotic initiation factor-2 (eIF2α) reduces protein synthesis and enhances apoptosis in response to proteasome inhibition. J Biol Chem, 280(14):14189-14202.

[21]Jiang TX, Zou JB, Zhu QQ, et al., 2019. SIP/CacyBP promotes autophagy by regulating levels of BRUCE/Apollon, which stimulates LC3-I degradation. Proc Natl Acad Sci USA, 116(27):13404-13413.

[22]Jung CH, Ro SH, Cao J, et al., 2010. mTOR regulation of autophagy. FEBS Lett, 584(7):1287-1295.

[23]Kedkovid R, Woonwong Y, Arunorat J, et al., 2018. Porcine circovirus type 3 (PCV3) infection in grower pigs from a Thai farm suffering from porcine respiratory disease complex (PRDC). Vet Microbiol, 215:71-76.

[24]Komatsu M, Waguri S, Chiba T, et al., 2006. Loss of autophagy in the central nervous system causes neurodegeneration in mice. Nature, 441(7095):880-884.

[25]Ku X, Chen F, Li P, et al., 2017. Identification and genetic characterization of porcine circovirus type 3 in China. Transbound Emerg Dis, 64(3):703-708.

[26]Kumar SH, Rangarajan A, 2009. Simian virus 40 small T antigen activates AMPK and triggers autophagy to protect cancer cells from nutrient deprivation. J Virol, 83(17):8565-8574.

[27]Kwon T, Yoo SJ, Park CK, et al., 2017. Prevalence of novel porcine circovirus 3 in Korean pig populations. Vet Microbiol, 207:178-180.

[28]Liu J, Wang HL, Gu JY, et al., 2017. BECN1-dependent CASP2 incomplete autophagy induction by binding to rabies virus phosphoprotein. Autophagy, 13(4):739-753.

[29]Mizushima N, Yoshimori T, Levine B, 2010. Methods in mammalian autophagy research. Cell, 140(3):313-326.

[30]Mohamud Y, Shi JY, Qu JY, et al., 2018. Enteroviral infection inhibits autophagic flux via disruption of the snare complex to enhance viral replication. Cell Rep, 22(12):3292-3303.

[31]Palinski R, Piñeyro P, Shang PC, et al., 2017. A novel porcine circovirus distantly related to known circoviruses is associated with porcine dermatitis and nephropathy syndrome and reproductive failure. J Virol, 91(1):e01879-16.

[32]Pankiv S, Clausen TH, Lamark T, et al., 2007. p62/SQSTM1 binds directly to Atg8/LC3 to facilitate degradation of ubiquitinated protein aggregates by autophagy. J Biol Chem, 282(33):24131-24145.

[33]Parzych KR, Klionsky DJ, 2014. An overview of autophagy: morphology, mechanism, and regulation. Antioxid Redox Signal, 20(3):460-473.

[34]Pei JJ, Zhao MQ, Ye ZD, et al., 2014. Autophagy enhances the replication of classical swine fever virus in vitro. Autophagy, 10(1):93-110.

[35]Phan TG, Giannitti F, Rossow S, et al., 2016. Detection of a novel circovirus PCV3 in pigs with cardiac and multi-systemic inflammation. Virol J, 13(1):184.

[36]Poole B, Ohkuma S, 1981. Effect of weak bases on the intralysosomal pH in mouse peritoneal macrophages. J Cell Biol, 90(3):665-669.

[37]Qian G, Liu DD, Hu JF, et al., 2017. Ochratoxin A-induced autophagy in vitro and in vivo promotes porcine circovirus type 2 replication. Cell Death Dis, 8(6):e2909.

[38]Ravikumar B, Sarkar S, Davies JE, et al., 2010. Regulation of mammalian autophagy in physiology and pathophysiology. Physiol Rev, 90(4):1383-1435.

[39]Sarkar S, 2013. Regulation of autophagy by mTOR-dependent and mTOR-independent pathways: autophagy dysfunction in neurodegenerative diseases and therapeutic application of autophagy enhancers. Biochem Soc Trans, 41(5):1103-1130.

[40]Saxton RA, Sabatini DM, 2017. mTOR signaling in growth, metabolism, and disease. Cell, 168(6):960-976.

[41]Shan Y, Liu ZQ, Li GW, et al., 2018. Nucleocapsid protein from porcine epidemic diarrhea virus isolates can antagonize interferon-λ production by blocking the nuclear factor-κB nuclear translocation. J Zhejiang Univ-Sci B (Biomed & Biotechnol), 19(7):570-580.

[42]Shen HQ, Liu XH, Zhang PF, et al., 2020. Porcine circovirus 3 Cap inhibits type I interferon signaling through interaction with STAT2. Virus Res, 275:197804.

[43]Song ZQ, Liao ZJ, Hu YF, et al., 2019. Development and optimization of an intergeneric conjugation system and analysis of promoter activity in Streptomyces rimosus M527. J Zhejiang Univ-Sci B (Biomed & Biotechnol), 20(11):891-900.

[44]Stadejek T, Woźniak A, Miłek D, et al., 2017. First detection of porcine circovirus type 3 on commercial pig farms in Poland. Transbound Emerg Dis, 64(5):1350-1353.

[45]Tischer I, Rasch R, Tochtermann G, 1974. Characterization of papovavirus-and picornavirus-like particles in permanent pig kidney cell lines. Zentralbl Bakteriol Orig A, 226(2):153-167.

[46]Tochetto C, Lima DA, Varela APM, et al., 2018. Full-genome sequence of porcine circovirus type 3 recovered from serum of sows with stillbirths in Brazil. Transbound Emerg Dis, 65(1):5-9.

[47]Wiegering A, Rüther U, Gerhardt C, 2019. The role of primary cilia in the crosstalk between the ubiquitin–proteasome system and autophagy. Cells, 8(3):241.

[48]Xu CM, Wang M, Song ZB, et al., 2018. Pseudorabies virus induces autophagy to enhance viral replication in mouse neuro-2a cells in vitro. Virus Res, 248:44-52.

[49]Ye XY, Berg M, Fossum C, et al., 2018. Detection and genetic characterisation of porcine circovirus 3 from pigs in Sweden. Virus Genes, 54(3):466-469.

[50]Yin HC, Shao SL, Jiang XJ, et al., 2019. Interactions between autophagy and DNA viruses. Viruses, 11(9):776.

[51]Yuzhakov AG, Raev SA, Alekseev KP, et al., 2018. First detection and full genome sequence of porcine circovirus type 3 in Russia. Virus Genes, 54(4):608-611.

[52]Zhai NH, Liu K, Li H, et al., 2019. PCV2 replication promoted by oxidative stress is dependent on the regulation of autophagy on apoptosis. Vet Res, 50(1):19.

[53]Zheng S, Wu X, Zhang L, et al., 2017. The occurrence of porcine circovirus 3 without clinical infection signs in Shandong Province. Transbound Emerg Dis, 64(5):1337-1341.

[54]Zhong L, Hu J, Shu W, et al., 2015. Epigallocatechin-3-gallate opposes HBV-induced incomplete autophagy by enhancing lysosomal acidification, which is unfavorable for HBV replication. Cell Death Dis, 6:e1770.

[55]Zhu BL, Xu F, Li J, et al., 2012a. Porcine circovirus type 2 explores the autophagic machinery for replication in PK-15 cells. Virus Res, 163(2):476-485.

[56]Zhu BL, Zhou YS, Xu F, et al., 2012b. Porcine circovirus type 2 induces autophagy via the AMPK/ERK/TSC2/mTOR signaling pathway in PK-15 cells. J Virol, 86(22):12003-12012.

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