Differential suppression of persistent insect specific viruses in trans-infected wMel and wMelPop-CLA Aedes-derived mosquito lines

Abstract

Wolbachia suppresses the replication of +ssRNA viruses such as dengue and Zika viruses in Aedes aegypti mosquitoes. However, the range of viruses affected by this endosymbiont is yet to be explored. Recently, novel insect-specific viruses (ISVs) have been described from numerous mosquito species and mosquito-derived cell lines. Cell-fusing agent virus (Flaviviridae) and Phasi Charoen-like virus (Bunyaviridae) persistently infect the Ae. aegypti cell line Aag2 which has been used for experimental studies with both the wMel and wMelPop-CLA strains. Wolbachia was found to restrict the replication of CFAV but not the PCLV infection in these lines. Furthermore, an additional Ae. albopictus cell line (RML-12) which contained either wMel or wMelPop-CLA was assessed. While no infectious +ssRNA or dsRNA viruses were detected, a PCLV infection was identified. These observations provide additional evidence to support that insect-specific, +ssRNA viruses can be suppressed in cell culture by Wolbachia but -ssRNA viruses may not.

Exploiting insect-specific viruses as a novel strategy to control vector-borne disease

“…The study found that field-caught mosquitoes with Wolbachia had higher titers and rates of ISV infections, and Wolbachia infected mosquitoes reared in the laboratory had higher ISV titers compared to their uninfected counterparts. These results contrast in vitro studies where Wolbachia infections reduce CFAV below detection limits and have no effect on PCLV titers [52][53][54]. Further investigations are required to determine the interactions of ISVs with other symbionts.…”

“…In theory, a vertically transmitted ISV could hitchhike with Wolbachia into naïve populations and enhance the anti-viral effect by a distinct mechanism. For example, while Wolbachia does not inhibit the bunyavirus PCLV, PCLV is the only ISV to show inhibition against a negative strand RNA virus, La Crosse virus [14,52,54]. Similarly, it would be interesting to determine if ISVs have played an incidental role in DENV transmission reduction in Wolbachiacolonized mosquitoes in the field.…”

Uncovering the Worldwide Diversity and Evolution of the Virome of the Mosquitoes Aedes aegypti and Aedes albopictus

“…PCLV is also known to infect the Ae. albopictus RML-12 cell line [ 157 ]. It is also well-established that the Culex Y virus ( Birnaviridae ) is a common laboratory contaminant of Ae.…”

Wolbachia modulates prevalence and viral load of Culex pipiens densoviruses in natural populations

“…Recent studies have shown that Wolbachia not only facilitates DNA ISVs in mosquitoes but also RNA ISVs, showing that facilitation could be a dominant outcome of Wolbachia –ISV interactions independent of viral genetic materials. Indeed, in cells, w AlbB enhanced the replication of Aedes albopictus Negev‐like virus ( Virgaviridae ) (Bishop, Parry, & Asgari, 2020), and neither w MelPop nor w Mel restricted the replication of Phaesi Chareon‐like virus ( Bunyaviridae ) (McLean, Dainty, Flores, & O’Neill, 2019). Facilitation by Wolbachia has also been observed for RNA flavivirus infection in A. aegypti carrying w Mel compared to their Wolbachia ‐free counterparts (Amuzu et al., 2018).…”

“…Facilitation by Wolbachia has also been observed for RNA flavivirus infection in A. aegypti carrying w Mel compared to their Wolbachia ‐free counterparts (Amuzu et al., 2018). In fact, among the studied ISVs, Cell‐Fusing Agent virus ( Flaviviridae ) replication was the only mosquito ISV to be restricted by w MelPop, w Mel and w AlbB in transinfected A. aegypti ‐derived cell lines (Bishop et al., 2020; McLean et al, 2019; Schnettler, Sreenu, Mottram, & McFarlane, 2016; Zhang, Etebari, & Asgari, 2016). Therefore, it is possible that ecological differences between ISVs and arboviruses contribute to the different nature of interactions: (a) their presence in all life stages (while arboviruses are mostly restricted to female adults) (Ajamma et al., 2018; Bolling et al., 2012; Haddow et al., 2013; Kawakami et al., 2016; Saiyasombat et al., 2011; Sang et al., 2003); (b) their prevalence (the first studies conducted on ISVs demonstrated that they were highly prevalent (Altinli, Lequime, et al, 2019; Farfan‐Ale et al., 2009; Goenaga et al., 2014; Parry & Asgari, 2018); and (c) transmission mode (ISVs being probably more frequently vertically transmitted than arboviruses) (Agboli et al., 2019; Lequime & Lambrechts, 2014; Lequime, Paul, & Lambrechts, 2016).…”