Journal Article

Human Papillomavirus (HPV) Upregulates the Cellular Deubiquitinase UCHL1 to Suppress the Keratinocyte's Innate Immune Response

Jha, Veena, Tummers, Bart, Offringa, Rienk, Biryukov, Jennifer L., Boer, Judith M., Meyers, Craig, Guardavaccaro, Daniele, Melief, Cornelis J. M., Karim, Rezaul, van Ommen, Gert-Jan B., Backendorf, Claude, van der Burg, Sjoerd H., Alam, Samina

2013

Overview

Persistent infection of basal keratinocytes with high-risk human papillomavirus (hrHPV) may cause cancer. Keratinocytes are equipped with different pattern recognition receptors (PRRs) but hrHPV has developed ways to dampen their signals resulting in minimal inflammation and evasion of host immunity for sustained periods of time. To understand the mechanisms underlying hrHPV's capacity to evade immunity, we studied PRR signaling in non, newly, and persistently hrHPV-infected keratinocytes. We found that active infection with hrHPV hampered the relay of signals downstream of the PRRs to the nucleus, thereby affecting the production of type-I interferon and pro-inflammatory cytokines and chemokines. This suppression was shown to depend on hrHPV-induced expression of the cellular protein ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) in keratinocytes. UCHL1 accomplished this by inhibiting tumor necrosis factor receptor-associated factor 3 (TRAF3) K63 poly-ubiquitination which lead to lower levels of TRAF3 bound to TANK-binding kinase 1 and a reduced phosphorylation of interferon regulatory factor 3. Furthermore, UCHL1 mediated the degradation of the NF-kappa-B essential modulator with as result the suppression of p65 phosphorylation and canonical NF-κB signaling. We conclude that hrHPV exploits the cellular protein UCHL1 to evade host innate immunity by suppressing PRR-induced keratinocyte-mediated production of interferons, cytokines and chemokines, which normally results in the attraction and activation of an adaptive immune response. This identifies UCHL1 as a negative regulator of PRR-induced immune responses and consequently its virus-increased expression as a strategy for hrHPV to persist.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: 3T3 Cells / Animals / Biology / Cells, Cultured / Cytokines / Cytokines - immunology / Cytokines - metabolism / Female / Gene Expression Regulation, Enzymologic - immunology / Gene Expression Regulation, Viral - immunology / Health aspects / Host-parasite relationships / Human papillomavirus / Human papillomavirus 16 - immunology / Human papillomavirus 16 - metabolism / Humans / Immune response / Immune system / Immunity, Innate / Keratinocytes / Keratinocytes - enzymology / Keratinocytes - immunology / Keratinocytes - pathology / Keratinocytes - virology / Kinases / Medical research / Mice / Papillomavirus infections / Papillomavirus Infections - enzymology / Papillomavirus Infections - immunology / Papillomavirus Infections - pathology / Phosphorylation - immunology / Physiological aspects / Protein-Serine-Threonine Kinases - immunology / Protein-Serine-Threonine Kinases - metabolism / Proteins / Signal Transduction - immunology / TNF Receptor-Associated Factor 3 - immunology / TNF Receptor-Associated Factor 3 - metabolism / Transcription Factor RelA - immunology / Transcription Factor RelA - metabolism / Ubiquitin / Ubiquitin Thiolesterase - biosynthesis / Ubiquitin Thiolesterase - immunology / Ubiquitination - immunology / Up-Regulation - immunology / Uterine Cervical Neoplasms - immunology / Uterine Cervical Neoplasms - metabolism / Uterine Cervical Neoplasms - pathology / Uterine Cervical Neoplasms - virology