Contrasting Roles of Endosomal pH and the Cytoskeleton in Infection of Human Glial Cells by JC Virus and Simian Virus 40

Abstract

Infection of eukaryotic cells by pathogens requires the efficient use of host cell endocytic and cytoplasmic transport mechanisms. Understanding how these cellular functions are exploited by microorganisms allows us to better define the basic biology of pathogenesis while providing better insight into normal cellular functions. In this report we compare and contrast intracellular transport and trafficking of the human polyomavirus JC virus (JCV) with that of simian virus 40 (SV40). We have previously shown that infection of human glial cells by JCV requires clathrin-dependent endocytosis. In contrast, infection of cells by SV40 proceeds by caveoladependent endocytosis. We now examine the roles of endosomal pH and the cellular cytoskeleton during infection of glial cells by both viruses. Our results demonstrate that JCV infection is sensitive to disruption of endosomal pH, whereas SV40 infection is pH independent. Infection by JCV is inhibited by treatment of glial cells with cytochalasin D, nocodazole, and acrylamide, whereas SV40 infection is affected only by nocodazole. These data point to critical differences between JCV and SV40 in terms of endocytosis and intracellular trafficking of their DNA genomes to the nucleus. These data also suggest a unique sequential involvement of cytoskeletal elements during infection of glial cells by JCV.

Transient cytochalasin-D treatment induces apically administered rAAV2 across tight junctions for transduction of enterocytes

“…Treatment with Cyto-D increases the internalization of bacteria Salmonella typhimurium and Proteus mirabilis to the polarized HT-29 and Caco-2 enterocytes (Wells et al, 1998). On the other hand, Cyto-D-induced actin disruption has also been associated with reduced infectivity of West Nile virus in African green monkey kidney epithelial cells (Chu & Ng, 2002, 2004, porcine circovirus 2 in porcine monocytic cell line 3D4/31 (Misinzo et al, 2005), and human polyomavirus JC virus in human glial cells (Ashok & Atwood, 2003). In this study, a similar reduction in rAAV2 transduction of 293, HT-1080, HeLa and HepG2 cells was observed.…”

Efficient gene transfer using the human JC virus-like particle that inhibits human colon adenocarcinoma growth in a nude mouse model

“…The use of siRNAs targeted against JCV large tumor and agnoprotein have been shown to be effective at inhibiting JCV replication. [38][39][40] Therefore, it may be possible to deliver siRNA expression plasmids by the JCV VLP into the JCVinfected cells, such as oligodendrocytes, and thus inhibit JCV replication because JCV VLP and the virus seem to share the same cell surface receptor.…”

“…The virus may then be transported from the cytosol to the nucleus through the actin cytoskeleton. 39 In addition to this cytoskeleton transport of the virus, a putative nuclear localization signal (MAPTKRKGERKD) in the N-terminal region of VP1 may mediate nuclear translocation through nuclear pore. 36 The virus would seem then to uncoat, which exposes the encapsidated DNA to the nucleus allowing gene expression.…”

Nuclear Entry Mechanism of the Human Polyomavirus JC Virus-like Particle

“…For construction of ⌬NLS-VP1, three amino acids, Lys 5 , Arg 6 , and Lys 7 , of wtVP1 were replaced with Ala, Gly, and Ala, respectively, by site-directed mutagenesis. The DNA fragment encoding ⌬NLS-VP1 was also subcloned into pET-15b.…”

“…The cytoplasmic transport of JCV in eukaryotic cells is dependent on a complex network of three types of cytoskeletal elements: microtubules, microfilaments, and intermediate filaments (6). After reaching the nucleus, the viral DNA undergoes replication and is transcribed into RNA, which is followed by the production of viral proteins and virion maturation.…”