Functional association of cellular microtubules with viral capsid assembly supports efficient hepatitis B virus replication

Abstract

Viruses exploit host factors and environment for their efficient replication. The virus-host interaction mechanisms for achieving an optimal hepatitis B virus (HBV) replication have been largely unknown. Here, a single cell cloning revealed that HepAD38 cells, a widely-used HBV-inducible cell line, contain cell clones with diverse permissiveness to HBV replication. The HBV permissiveness was impaired upon treatment with microtubule inhibitor nocodazole, which was identified as an HBV replication inhibitor from a pharmacological screening. In the microtubule-disrupted cells, the efficiency of HBV capsid assembly was remarkably decreased without significant change in pre-assembly process. We further found that HBV core interacted with tubulin and co-localized with microtubule-like fibriforms, but this association was abrogated upon microtubule-disassembly agents, resulting in attenuation of capsid formation. Our data thus suggest a significant role of microtubules in the efficient capsid formation during HBV replication. In line with this, a highly HBV permissive cell clone of HepAD38 cells showed a prominent association of core-microtubule and thus a high capacity to support the capsid formation. These findings provide a new aspect of virus-cell interaction for rendering efficient HBV replication.

Epidermal growth factor receptor is a host-entry cofactor triggering hepatitis B virus internalization

“…During the life cycle, the activity of HBV replication was not affected by depletion of EGFR ( Fig. 2B), as demonstrated using HepG2.2.15.7 cells (which autonomously replicate HBV but do not support HBV attachment and internalization) (11,12). While viral attachment was not decreased in EGFR-knockdown cells (Fig.…”

“…1. (F and G) HBV infection assay using HepG2-NTCP (F) and dHepaRG cells and PHH (G) upon treatment with or without the indicated compounds [NTCP (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) or NTCP (131-150) in F; gefitinib in G]. HBs levels (F and G) and cccDNA levels (F) were detected to evaluate HBV infection.…”

“…HBV used in this study was derived from Hep38.7-Tet cells (genotype D) (6,11). PHHs, dHepaRG, and HepG2-NTCP were infected with HBV as previously described (6).…”

“…PHHs, dHepaRG, and HepG2-NTCP were infected with HBV as previously described (6). HBV infection was evaluated by detecting HBV surface protein (HBs), HBV core protein (HBc), cccDNA, and/or HBV DNA (6,11). Additional experimental procedures are described in SI Appendix, Materials and Methods.…”

Host functions used by hepatitis B virus to complete its life cycle: Implications for developing host-targeting agents to treat chronic hepatitis B

“…Along the same lines, while Hsp90 interacts with the core to stabilize the capsid, Hsp40 is yet another chaperone protein that antagonizes this protein-protein interaction to destabilize capsid and also degrades HBx protein (Shim et al, 2011; Sohn et al, 2006). Whether HBV capsid assembly occurs in a specific cell compartment is largely unknown, but a recent study indicates that an intact cellular microtubule network is required for capsid formation (Iwamoto et al, 2017). …”