Chikungunya virus requires an intact microtubule network for efficient viral genome delivery

Abstract

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus, which has rapidly spread around the globe thereby causing millions of infections. CHIKV is an enveloped virus belonging to the Togaviridae family and enters its host cell primarily via clathrin-mediated endocytosis. Upon internalization, the endocytic vesicle containing the virus particle moves through the cell and delivers the virus to early endosomes where membrane fusion is observed. Thereafter, the nucleocapsid dissociates and the viral RNA is translated into proteins. In this study, we examined the importance of the microtubule network during the early steps of infection and dissected the intracellular trafficking behavior of CHIKV particles during cell entry. We observed two distinct CHIKV intracellular trafficking patterns prior to membrane hemifusion. Whereas half of the CHIKV virions remained static during cell entry and fused in the cell periphery, the other half showed fast-directed microtubule-dependent movement prior to delivery to Rab5-positive early endosomes and predominantly fused in the perinuclear region of the cell. Disruption of the microtubule network reduced the number of infected cells. At these conditions, membrane hemifusion activity was not affected yet fusion was restricted to the cell periphery. Furthermore, follow-up experiments revealed that disruption of the microtubule network impairs the delivery of the viral genome to the cell cytosol. We therefore hypothesize that microtubules may direct the particle to a cellular location that is beneficial for establishing infection or aids in nucleocapsid uncoating.

Microfilaments and Microtubules Alternately Coordinate the Multistep Endosomal Trafficking of Classical Swine Fever Virus

“…Early studies have shown that microtubules regulate virus infection (64). As pathogenic cargos, viruses require microtubules for transport to and from their intracellular sites of replication (65). Nocodazole disrupts microtubules and inhibits vesicular trafficking, including transport between early and late endosomes.…”

Alphavirus nsP2 protease structure and cleavage prediction: Possible relevance to the pathogenesis of viral arthritis

“…Cleavage of many cytoskeletal proteins likely contributes to altered virus and host component trafficking, yet cytoskeletal drugs have remained mostly ineffective against alphaviruses. These drugs may help prevent initial endocytosis, [56,57] internalization of replication complexes in spherules into cytopathic vacuoles, [58] and virion release, yet alphaviruses are known to still replicate in their presence. [59,60] In the extracellular matrix, the most obviously affected region in arthritis, nsP2pro likely cleaves many structural proteins.…”

Intracellular Interactions Between Arboviruses and Wolbachia in Aedes aegypti

“…aegypti also suggests that tubulin is highly associated with DENV infection in the mosquito host with roles in transport and assembly ( Guo et al., 2010 ). In CHIKV infection, impaired viral delivery from the cell surface to the cytoplasm occurred when microtubule network is disrupted ( Hoornweg et al., 2020 ). While ZIKV’s effect on Ae.…”

“…This is the first demonstration to confirm the direct involvement of Wolbachia in arbovirus binding and entry by taking advantage of the same host cytoskeletal proteins DENV and ZIKV utilize. Although there is a lack of data that demonstrates the same mechanism in CHIKV, this arbovirus necessitates an intact microtubule network consisting of alpha-tubulin (same family as beta-tubulin) for efficient viral entry and genome delivery to replication sites ( Hoornweg et al., 2020 ).…”