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. 2020 Jan 17;94(3):e01360-19.
doi: 10.1128/JVI.01360-19. Print 2020 Jan 17.

Genome-Wide Transcriptome Analysis of Human Papillomavirus 16-Infected Primary Keratinocytes Reveals Subtle Perturbations Mostly due to E7 Protein Expression

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Genome-Wide Transcriptome Analysis of Human Papillomavirus 16-Infected Primary Keratinocytes Reveals Subtle Perturbations Mostly due to E7 Protein Expression

Malgorzata Bienkowska-Haba et al. J Virol. .

Erratum in

Abstract

It is established that the host cell transcriptomes of natural lesions, organotypic rafts, and human papillomavirus (HPV)-immortalized keratinocytes are altered in the presence of HPV genomes. However, the establishment of HPV-harboring cell lines requires selection and immortalization, which makes it impossible to distinguish between alterations directly induced by HPV or indirectly by the need for immortalization or selection. To address direct effects of HPV infection on the host cell transcriptome, we have used our recently established infection model that allows efficient infection of primary keratinocytes with HPV16 virions. We observed only a small set of genes to be deregulated at the transcriptional level at 7 days postinfection (dpi), most of which fall into the category regulated by pocket proteins pRb, p107, and p130. Furthermore, cell cycle genes were not deregulated in cells infected with a virus lacking E7 despite the presence of episomal genome and viral transcripts. These findings imply that the majority of transcriptional changes are due to the E7 protein impairing pocket protein function. Additional pathways, such as the Fanconi anemia-BRCA pathway, became perturbed only after long-term culturing of infected cells. When grown as organotypic raft cultures, keratinocytes infected with wild-type but not E7 mutant virus had perturbed transcriptional regulation of pathways previously identified in natural lesions and in rafts derived from immortalized keratinocytes. We conclude that the HPV infection model provides a valuable tool to distinguish immediate transcriptional alterations from those induced by persistent infection and the need for selection and immortalization.IMPORTANCE To establish infection and complete the viral life cycle, human papillomavirus (HPV) needs to alter the transcriptional program of host cells. Until recently, studies were restricted to keratinocyte-derived cell lines immortalized by HPV due to the lack of experimental systems to efficiently infect primary keratinocytes. Need for selection and immortalization made it impossible to distinguish between alterations induced by HPV and secondary adaptation due to selection and immortalization. With our recent establishment of an extracellular matrix (ECM)-to-cell transfer system allowing efficient infection of primary keratinocytes, we were able to identify transcriptional changes attributable to HPV16 infection. Most perturbed genes fall into the class of S-phase genes, which are regulated by pocket proteins. Indeed, infection with viruses lacking E7 abrogated most transcriptional changes. It is important to note that many transcriptional alterations thought to be important for the HPV life cycle are actually late events that may reflect immortalization and, possibly, disease progression.

Keywords: E7; HPV16; RB; infection model; organotypic raft culture; p53; pocket protein; primary foreskin keratinocytes; transcriptome.

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Figures

FIG 1
FIG 1
HPV16-induced changes to the host cell transcriptome at 7 dpi. (A) Representative RNAscope images of HPV16-infected HFK at 7 dpi. (B) Transcripts per million (TPM) values of viral E6 and E1̂E4 transcript reads in samples from HPV16-infected and -immortalized cells grown as a monolayer in the presence of Y-27632. (C) Numbers of genes whose expression was significantly modified in HPV16-infected and -immortalized cells. (D) Heat map illustrating the cluster of genes whose expression was significantly modified in HPV16-immortalized cells analyzed as sample groups from controls and HPV16-immortalized and HPV16-infected cells grown in the presence of Y-27632. (E) Venn diagram showing the number of altered host genes common to HPV16-infected and -immortalized cells grown in the presence of Y-27632. (F) Principal-component analysis (PCA) diagram of RNA sequencing results from HPV16-infected and -immortalized cells grown as a monolayer with and without Y-27632 based on TPM values in the bulk RNA-seq data set. Similarities between data sets are correlated to the distances in the projection of the space defined by the principal components.
FIG 2
FIG 2
Extended culturing of HPV16-infected cells increases the number of deregulated genes. (A) Numbers of down- or upregulated genes in WT and E7-TTL mutant HPV16-infected and HPV16-immortalized HFK (p2/3, 27 to 33 dpi; p3/4, 36 to 55 dpi; p4/5, 47 to 63 dpi). All cells were infected and cultured in the absence of Y-27632. (B) TPM values of viral transcript reads in samples from HPV16-infected and HPV16-immortalized cells used for analysis. (C) Heat map analysis of genes altered in HPV16-infected cells. The subgroup of 113 genes identified in Fig. 1 were selected for the analysis and analyzed as sample groups from controls and WT and E7-TTL HPV16-infected cells at different times postinfection. (D) Venn diagram showing the overlap between differentially expressed genes in HPV16-immortalized and -infected cells (p4/5). (E) PCA analysis of RNA sequencing data from control and WT and E7-TTL HPV16-infected cells based on TPM values in the bulk RNA-seq data set.
FIG 3
FIG 3
Members of the Fanconi anemia-BRCA pathway become activated upon long-term culturing of HPV16-infected HFK. (A) Downstream effect analysis of genes altered in HPV16-infected HFK at 63 dpi. The top 5 molecular and cellular functions affected by HPV16 are shown. (B) Fold changes of altered genes of the Fanconi anemia-BRCA pathway in HPV16-infected versus control cells at 63 dpi. (C) Genes of the Fanconi anemia-BRCA pathway highlighted in pink are transcriptionally altered in HPV16-infected cells at 63 dpi.
FIG 4
FIG 4
IPA analysis of genes falling into the cell cycle of chromosomal replication category. (A) Genes highlighted in pink are transcriptionally altered in HPV16-infected cells at 7 dpi. (B) Downstream effect analysis of genes altered in HPV16-infected HFK at 7 dpi. The top 5 molecular and cellular functions affected by HPV16 are shown.
FIG 5
FIG 5
HPV16-induced changes in the transcriptome of cells grown in organotypic rafts. Viral transcript levels in undifferentiated (mono) and differentiated cells infected with WT and E7-TTL mutant viruses. RNA and DNA were collected from monolayer cells at 7 dpi and from 20-day-old rafts. Viral E6 transcript (A) and DNA (B) are expressed as ΔCT relative to the household gene controls cyclophilin A (A) and β-actin (B), respectively. (C) Detection of viral DNA in infected rafts by highly sensitive fluorescent in situ hybridization. (D) TPM values for viral transcripts in samples used for sequencing. (E) Numbers of genes whose expression was significantly modified in WT and E7-TTL HPV16-infected cells grown in organotypic raft cultures.
FIG 6
FIG 6
The Fanconi anemia-BRCA pathway is activated in HPV16-infected organotypic rafts. (A) Downstream effect analysis of genes altered in HPV16-infected rafts. The top 5 molecular and cellular functions affected by HPV16 are shown. (B) Genes of the Fanconi anemia-BRCA pathway highlighted in pink are transcriptionally altered in HPV16-infected rafts. (C) Fold changes of altered genes of the Fanconi anemia-BRCA pathway in HPV16-infected versus control rafts based on next-generation sequencing (NGS) analysis.
FIG 7
FIG 7
Immunofluorescent staining of organotypic rafts. Organotypic rafts derived from control and WT and E7-TTL HPV16-infected cells were paraffin embedded, sectioned, and processed for staining of S-phase markers (PCNA and MCM7) as well as markers of the DNA damage response (RPA2 and Rad51).
FIG 8
FIG 8
Genes regulated by the JAK/STAT signaling axis are downregulated in HPV16-infected organotypic rafts.
FIG 9
FIG 9
p53, E6 protein, and viral genome in organotypic rafts. (A) Organotypic rafts derived from control (ctrl) and from WT and E7-TTL HPV16-infected HFK were paraffin embedded, sectioned, and processed for detection of p53 and viral DNA (vDNA) by immunofluorescent and fluorescent in situ hybridization, respectively. Adjacent sections were used for in situ hybridization and immunofluorescent staining. (B) Furthermore, E6 protein was detected using the OncoE6 cervical test. Note detection of p53 despite the presence of E6 protein and viral genome E7-TTL-harboring rafts.

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References

    1. Zur-Hausen H, de Villiers EM. 1994. Human papillomaviruses. Annu Rev Microbiol 48:427–447. doi:10.1146/annurev.mi.48.100194.002235. - DOI - PubMed
    1. Roberts JN, Buck CB, Thompson CD, Kines R, Bernardo M, Choyke PL, Lowy DR, Schiller JT. 2007. Genital transmission of HPV in a mouse model is potentiated by nonoxynol-9 and inhibited by carrageenan. Nat Med 13:857–861. doi:10.1038/nm1598. - DOI - PubMed
    1. Doorbar J. 2005. The papillomavirus life cycle. J Clin Virol 32 Suppl 1:S7–S15. doi:10.1016/j.jcv.2004.12.006. - DOI - PubMed
    1. Hummel M, Hudson JB, Laimins LA. 1992. Differentiation-induced and constitutive transcription of human papillomavirus type 31b in cell lines containing viral episomes. J Virol 66:6070–6080. - PMC - PubMed
    1. Roman A, Munger K. 2013. The papillomavirus E7 proteins. Virology 445:138–168. doi:10.1016/j.virol.2013.04.013. - DOI - PMC - PubMed

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