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Genome and infection characteristics of human parechovirus type 1: the interplay between viral infection and type I interferon antiviral system.

Chang JT, Yang CS, Chen YS, Chen BC, Chiang AJ, Chang YH, Tsai WL, Lin YS, Chao D, Chang TH - PLoS ONE (2015)

Bottom Line: Human parechoviruses (HPeVs), members of the family Picornaviridae, are associated with severe human clinical conditions such as gastrointestinal disease, encephalitis, meningitis, respiratory disease and neonatal sepsis.A facilitated cytopathic effect and increased viral titers were reached after serial viral passages in Vero cells, with viral genome mutation found in later passages.The characterization of the complete genome and infection features of HPeV1 provide comprehensive information about this newly isolated HPeV1 for further diagnosis, prevention or treatment strategies.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan; Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Department of Pediatrics; Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.

ABSTRACT
Human parechoviruses (HPeVs), members of the family Picornaviridae, are associated with severe human clinical conditions such as gastrointestinal disease, encephalitis, meningitis, respiratory disease and neonatal sepsis. A new contemporary strain of HPeV1, KVP6 (accession no. KC769584), was isolated from a clinical specimen. Full-genome alignment revealed that HPeV1 KVP6 shares high genome homology with the German strain of HPeV1, 7555312 (accession no. FM178558) and could be classified in the clade 1B group. An intertypic recombination was shown within the P2-P3 genome regions of HPeV1. Cell-type tropism test showed that T84 cells (colon carcinoma cells), A549 cells (lung carcinoma cells) and DBTRG-5MG cells (glioblastoma cells) were susceptible to HPeV1 infection, which might be relevant clinically. A facilitated cytopathic effect and increased viral titers were reached after serial viral passages in Vero cells, with viral genome mutation found in later passages. HPeV1 is sensitive to elevated temperature because 39C incubation impaired virion production. HPeV1 induced innate immunity with phosphorylation of interferon (IFN) regulatory transcription factor 3 and production of type I IFN in A549 but not T84 cells. Furthermore, type I IFN inhibited HPeV1 production in A549 cells but not T84 cells; T84 cells may be less responsive to type I IFN stimulation. Moreover, HPeV1-infected cells showed downregulated type I IFN activation, which indicated a type I IFN evasion mechanism. The characterization of the complete genome and infection features of HPeV1 provide comprehensive information about this newly isolated HPeV1 for further diagnosis, prevention or treatment strategies.

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HPeV1 downregulates type I IFN activity.(A) A549 and T84 cells (3×105) wereinfected with mock or HPeV1 at MOI = 5 for 6 h, then treated withIFNβ (1000 U/ml) for 18 h; untreated cells are indicated as ctrl.Immunoblotting of levels of phospho-STAT1 and total STAT1 in whole cellextracts. HPeV1 VP0 indicates viral infection and β-actin is aloading control. (B) Interferon-stimulated response element(ISRE) reporter assay was performed in A549 and T84 cells(3×105) transfected with ISRE-luciferase reporterplasmids (400 ng) and control vector pRL-TK (40 ng) for 24 h, theninfected with HPeV1 for 6 h. After 24 h of IFNβ (1000 U/ml)stimulation, ISRE luciferase activity was measured by dual-luciferaseassay and (C) RT-qPCR of mRNA expression. Data are mean± SD of at least 3 independent experiments. Studentt test, * p<0.05,*** p<0.005.
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pone.0116158.g006: HPeV1 downregulates type I IFN activity.(A) A549 and T84 cells (3×105) wereinfected with mock or HPeV1 at MOI = 5 for 6 h, then treated withIFNβ (1000 U/ml) for 18 h; untreated cells are indicated as ctrl.Immunoblotting of levels of phospho-STAT1 and total STAT1 in whole cellextracts. HPeV1 VP0 indicates viral infection and β-actin is aloading control. (B) Interferon-stimulated response element(ISRE) reporter assay was performed in A549 and T84 cells(3×105) transfected with ISRE-luciferase reporterplasmids (400 ng) and control vector pRL-TK (40 ng) for 24 h, theninfected with HPeV1 for 6 h. After 24 h of IFNβ (1000 U/ml)stimulation, ISRE luciferase activity was measured by dual-luciferaseassay and (C) RT-qPCR of mRNA expression. Data are mean± SD of at least 3 independent experiments. Studentt test, * p<0.05,*** p<0.005.

Mentions: Our results indicated that type I IFN post-treatment could not inhibit HPeV1infection and HPeV1 failed to activate STAT1 (Fig. 5); HPeV1 might feature a type I IFN evasionmachinery, which was described in other RNA virus infection models [44,45,46]. Type I IFN-activatedSTAT1 phosphorylation was reduced in HPeV1-infected A549 cells (Fig. 6A, left panel), with aslight difference in T84 cells (Fig. 6B, right panel), which might due to the low response to type IIFN of T84 cells. Another more sensitive assay revealed that HPeV1 attenuatedthe reporter luciferase activity of type I ISRE (Fig. 6B). Consistently, IFNβ induced the mRNAexpression of antiviral-associated proteins such as Viperin, IRF7, PKR, MxA andMAVS, which was significantly inhibited by HPeV1 in A549 and T84 cells (Fig. 6C). These resultssuggested that HPeV1 infection interfered in type I IFN signaling activation.The evasion of an antiviral mechanism would be important for HPeV1 replication,which also supported the inefficient anti-HPeV1 activity with type I IFNpost-treatment (Fig. 5A andB, lower panels).


Genome and infection characteristics of human parechovirus type 1: the interplay between viral infection and type I interferon antiviral system.

Chang JT, Yang CS, Chen YS, Chen BC, Chiang AJ, Chang YH, Tsai WL, Lin YS, Chao D, Chang TH - PLoS ONE (2015)

HPeV1 downregulates type I IFN activity.(A) A549 and T84 cells (3×105) wereinfected with mock or HPeV1 at MOI = 5 for 6 h, then treated withIFNβ (1000 U/ml) for 18 h; untreated cells are indicated as ctrl.Immunoblotting of levels of phospho-STAT1 and total STAT1 in whole cellextracts. HPeV1 VP0 indicates viral infection and β-actin is aloading control. (B) Interferon-stimulated response element(ISRE) reporter assay was performed in A549 and T84 cells(3×105) transfected with ISRE-luciferase reporterplasmids (400 ng) and control vector pRL-TK (40 ng) for 24 h, theninfected with HPeV1 for 6 h. After 24 h of IFNβ (1000 U/ml)stimulation, ISRE luciferase activity was measured by dual-luciferaseassay and (C) RT-qPCR of mRNA expression. Data are mean± SD of at least 3 independent experiments. Studentt test, * p<0.05,*** p<0.005.
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pone.0116158.g006: HPeV1 downregulates type I IFN activity.(A) A549 and T84 cells (3×105) wereinfected with mock or HPeV1 at MOI = 5 for 6 h, then treated withIFNβ (1000 U/ml) for 18 h; untreated cells are indicated as ctrl.Immunoblotting of levels of phospho-STAT1 and total STAT1 in whole cellextracts. HPeV1 VP0 indicates viral infection and β-actin is aloading control. (B) Interferon-stimulated response element(ISRE) reporter assay was performed in A549 and T84 cells(3×105) transfected with ISRE-luciferase reporterplasmids (400 ng) and control vector pRL-TK (40 ng) for 24 h, theninfected with HPeV1 for 6 h. After 24 h of IFNβ (1000 U/ml)stimulation, ISRE luciferase activity was measured by dual-luciferaseassay and (C) RT-qPCR of mRNA expression. Data are mean± SD of at least 3 independent experiments. Studentt test, * p<0.05,*** p<0.005.
Mentions: Our results indicated that type I IFN post-treatment could not inhibit HPeV1infection and HPeV1 failed to activate STAT1 (Fig. 5); HPeV1 might feature a type I IFN evasionmachinery, which was described in other RNA virus infection models [44,45,46]. Type I IFN-activatedSTAT1 phosphorylation was reduced in HPeV1-infected A549 cells (Fig. 6A, left panel), with aslight difference in T84 cells (Fig. 6B, right panel), which might due to the low response to type IIFN of T84 cells. Another more sensitive assay revealed that HPeV1 attenuatedthe reporter luciferase activity of type I ISRE (Fig. 6B). Consistently, IFNβ induced the mRNAexpression of antiviral-associated proteins such as Viperin, IRF7, PKR, MxA andMAVS, which was significantly inhibited by HPeV1 in A549 and T84 cells (Fig. 6C). These resultssuggested that HPeV1 infection interfered in type I IFN signaling activation.The evasion of an antiviral mechanism would be important for HPeV1 replication,which also supported the inefficient anti-HPeV1 activity with type I IFNpost-treatment (Fig. 5A andB, lower panels).

Bottom Line: Human parechoviruses (HPeVs), members of the family Picornaviridae, are associated with severe human clinical conditions such as gastrointestinal disease, encephalitis, meningitis, respiratory disease and neonatal sepsis.A facilitated cytopathic effect and increased viral titers were reached after serial viral passages in Vero cells, with viral genome mutation found in later passages.The characterization of the complete genome and infection features of HPeV1 provide comprehensive information about this newly isolated HPeV1 for further diagnosis, prevention or treatment strategies.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan; Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan; Department of Pediatrics; Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.

ABSTRACT
Human parechoviruses (HPeVs), members of the family Picornaviridae, are associated with severe human clinical conditions such as gastrointestinal disease, encephalitis, meningitis, respiratory disease and neonatal sepsis. A new contemporary strain of HPeV1, KVP6 (accession no. KC769584), was isolated from a clinical specimen. Full-genome alignment revealed that HPeV1 KVP6 shares high genome homology with the German strain of HPeV1, 7555312 (accession no. FM178558) and could be classified in the clade 1B group. An intertypic recombination was shown within the P2-P3 genome regions of HPeV1. Cell-type tropism test showed that T84 cells (colon carcinoma cells), A549 cells (lung carcinoma cells) and DBTRG-5MG cells (glioblastoma cells) were susceptible to HPeV1 infection, which might be relevant clinically. A facilitated cytopathic effect and increased viral titers were reached after serial viral passages in Vero cells, with viral genome mutation found in later passages. HPeV1 is sensitive to elevated temperature because 39C incubation impaired virion production. HPeV1 induced innate immunity with phosphorylation of interferon (IFN) regulatory transcription factor 3 and production of type I IFN in A549 but not T84 cells. Furthermore, type I IFN inhibited HPeV1 production in A549 cells but not T84 cells; T84 cells may be less responsive to type I IFN stimulation. Moreover, HPeV1-infected cells showed downregulated type I IFN activation, which indicated a type I IFN evasion mechanism. The characterization of the complete genome and infection features of HPeV1 provide comprehensive information about this newly isolated HPeV1 for further diagnosis, prevention or treatment strategies.

Show MeSH
Related in: MedlinePlus