Phosphoinositide 3'-Kinase γ Facilitates Polyomavirus Infection.

Paul Clark,Gretchen V Gee,Brandon S Albright,Ying Han,Benedetta Assetta,Daniel Dimaio,Walter J Atwood

doi:10.3390/v12101190

Paul Clark, Gretchen V Gee + Show 5 more

Open Access

https://doi.org/10.3390/v12101190

Copy DOI

Abstract

Polyomaviruses are small, non-enveloped DNA tumor viruses that cause serious disease in immunosuppressed people, including progressive multifocal leukoencephalopathy (PML) in patients infected with JC polyomavirus, but the molecular events mediating polyomavirus entry are poorly understood. Through genetic knockdown approaches, we identified phosphoinositide 3′-kinase γ (PI3Kγ) and its regulatory subunit PIK3R5 as cellular proteins that facilitate infection of human SVG-A glial cells by JCPyV. PI3Kα appears less important for polyomavirus infection than PI3Kγ. CRISPR/Cas9-mediated knockout of PIK3R5 or PI3Kγ inhibited infection by authentic JCPyV and by JC pseudovirus. PI3Kγ knockout also inhibited infection by BK and Merkel Cell pseudoviruses, other pathogenic human polyomaviruses, and SV40, an important model polyomavirus. Reintroduction of the wild-type PI3Kγ gene into the PI3Kγ knock-out SVG-A cells rescued the JCPyV infection defect. Disruption of the PI3Kγ pathway did not block binding of JCPyV to cells or virus internalization, implying that PI3Kγ facilitates some intracellular step(s) of infection. These results imply that agents that inhibit PI3Kγ signaling may have a role in managing polyomavirus infections.

Highlights

Human polyomaviruses establish lifelong, persistent, usually asymptomatic infections in most humans [1,2]
While surveying the ability of candidate cellular proteins to affect JC polyomavirus (JCPyV) entry, we found that transduction of SVG-A cells by JC pseudovirus (JCPsV) was inhibited by shRNAs that targeted PIK3R5, a regulatory subunit of phosphoinositide 30 -kinase γ (PI3Kγ)
SVG-A cells, a human glial cell line permissive for JCPyV infection [45], were infected with a lentivirus conferring puromycin resistance and expressing an shRNA targeting one of two independent sequences in PIK3R5 or with a control lentivirus expressing scrambled shRNA. shRNA-mediated knockdown of PIK3R5 mRNA in pooled puromycin-resistant SVG-A cells was confirmed by quantitative RT-PCR (Figure 1A)

Summary

Introduction

Persistent, usually asymptomatic infections in most humans [1,2]. Several polyomaviruses, including JC polyomavirus (JCPyV), BK polyomavirus (BKPyV), and Merkel cell polyomavirus (MCPyV), cause serious disease in immunocompromised patients. JCPyV normally replicates in the kidney and is the causative agent of progressive multifocal leukoencephalopathy (PML), a rapidly progressive, often fatal central nervous system demyelinating disease for which there are no effective treatments [2,3,4,5,6]. PML can be a fatal complication in a small fraction of patients receiving immunomodulatory antibodies as treatment for multiple sclerosis and other disorders [7,8,9,10,11,12]. In contrast to JCPyV, BKPyV causes pathology primarily localized to the reno-urinary tract, including polyomavirus-associated nephropathy (PyVAN)

Methods

Results

Conclusion