Limits...
Native Wolbachia from Aedes albopictus Blocks Chikungunya Virus Infection In Cellulo.

Raquin V, Valiente Moro C, Saucereau Y, Tran FH, Potier P, Mavingui P - PLoS ONE (2015)

Bottom Line: To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain.Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB.More broadly, this put into question the ecological role of Wolbachia symbiont in Ae. albopictus, but also the ability of the CHIKV to counteract Wolbachia's antiviral potential in vivo.

View Article: PubMed Central - PubMed

Affiliation: Université de Lyon, UMR5557 Ecologie Microbienne, CNRS, USC1190 INRA, VetAgro Sup, Université Lyon 1, Villeurbanne, France.

ABSTRACT
Wolbachia, a widespread endosymbiont of terrestrial arthropods, can protect its host against viral and parasitic infections, a phenotype called "pathogen blocking". However, in some cases Wolbachia may have no effect or even enhance pathogen infection, depending on the host-Wolbachia-pathogen combination. The tiger mosquito Aedes albopictus is naturally infected by two strains of Wolbachia, wAlbA and wAlbB, and is a competent vector for different arboviruses such as dengue virus (DENV) and chikungunya virus (CHIKV). Interestingly, it was shown in some cases that Ae. albopictus native Wolbachia strains are able to inhibit DENV transmission by limiting viral replication in salivary glands, but no such impact was measured on CHIKV replication in vivo. To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain. Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB. Using FISH, we observed CHIKV and wAlbB in the same mosquito cells, indicating that the virus is still able to enter the cell in the presence of the bacterium. Further work is needed to decipher molecular pathways involved in Wolbachia-CHIKV interaction at the cellular level, but this cellular model can be a useful tool to study the mechanism behind virus blocking phenotype induced by Wolbachia. More broadly, this put into question the ecological role of Wolbachia symbiont in Ae. albopictus, but also the ability of the CHIKV to counteract Wolbachia's antiviral potential in vivo.

Show MeSH

Related in: MedlinePlus

Effect of Wolbachia on CHIKV replication and infectiosity.Kinetics at MOI 0.1 of CHIKV RNA titer measured by RT-qPCR on total cellular RNA (A) and CHIKV infectious titer in supernatant measured by FFA (B) in presence of Wolbachia (wAlbB) or in cells cured from the bacteria by tetracycline treatment (TET). Error bars represent the standard deviation of the mean of three independent samples.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4414612&req=5

pone.0125066.g005: Effect of Wolbachia on CHIKV replication and infectiosity.Kinetics at MOI 0.1 of CHIKV RNA titer measured by RT-qPCR on total cellular RNA (A) and CHIKV infectious titer in supernatant measured by FFA (B) in presence of Wolbachia (wAlbB) or in cells cured from the bacteria by tetracycline treatment (TET). Error bars represent the standard deviation of the mean of three independent samples.

Mentions: As no viral inhibition was measured for CHIKV 06.21 in orally infected Ae. albopictus mosquitoes [26], we tested the interaction of wAlbB and CHIKV 06.21 in C6/36. First, we assessed that CHIKV replication was not affected by anti-Wolbachia tetracycline treatment, as viral RNA titer was not significantly different between C6/36_TET and C6/36_CTRL cells at MOIs of 0.1 (P = 0.45) and 3 (P = 0.68) (Fig 4). The viral RNA titer increased from 2 h to 72 h post-infection (pi), with a short eclipse phase between 8 h and 10 h pi, then decreased until 96 h to reach a plateau until day 7 pi. The viral replication was dramatically reduced in C6/36_wAlbB compared to C6/36_TET cells as measured by RT-qPCR after infection at MOI 0.1 (Fig 5A). The RNA titer significantly decreased in C6/36_wAlbB cells by at least ten-fold across all time-points. Interestingly, Wolbachia-mediated inhibition depended on the time of infection (Wolbachia*time interaction, P<2E-16), suggesting that presence of Wolbachia could delay virus replication as previously mentioned [43]. Although viral RNA titer decreased, inhibition was not complete with at least 4.81 log10 CHIKV RNA copies per ng total RNA in C6/36_wAlbB cells at day 1 pi, where Wolbachia antiviral effect seemed to be the strongest. CHIKV inhibition by wAlbB was also measured at the RNA infectious particles level using FFA assay on cell supernatants (Fig 5B). A major decrease of viral infectious titer was detected in C6/36_wAlbB compared to C6/36_TET cells, depending on the time post-infection (Wolbachia*time interaction, P = 0.00177). As for viral RNA, this suggests that Wolbachia-mediated inhibition of viral infectious particles production decreases with the time of infection, even if the time effect is lower than for viral RNA decrease. The wAlbB density was monitored in both CHIKV infected (CHIKV+) and uninfected (CHIKV-) cells using qPCR (Fig 6). The bacterial load did not vary according to viral infection (P = 0.228) but time had a significant effect (P<2E-16). The Wolbachia titer increased with time, ranging from 13.3 to 25.7 wsp/actin ratio at day 1 and 7 pi, respectively.


Native Wolbachia from Aedes albopictus Blocks Chikungunya Virus Infection In Cellulo.

Raquin V, Valiente Moro C, Saucereau Y, Tran FH, Potier P, Mavingui P - PLoS ONE (2015)

Effect of Wolbachia on CHIKV replication and infectiosity.Kinetics at MOI 0.1 of CHIKV RNA titer measured by RT-qPCR on total cellular RNA (A) and CHIKV infectious titer in supernatant measured by FFA (B) in presence of Wolbachia (wAlbB) or in cells cured from the bacteria by tetracycline treatment (TET). Error bars represent the standard deviation of the mean of three independent samples.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414612&req=5

pone.0125066.g005: Effect of Wolbachia on CHIKV replication and infectiosity.Kinetics at MOI 0.1 of CHIKV RNA titer measured by RT-qPCR on total cellular RNA (A) and CHIKV infectious titer in supernatant measured by FFA (B) in presence of Wolbachia (wAlbB) or in cells cured from the bacteria by tetracycline treatment (TET). Error bars represent the standard deviation of the mean of three independent samples.
Mentions: As no viral inhibition was measured for CHIKV 06.21 in orally infected Ae. albopictus mosquitoes [26], we tested the interaction of wAlbB and CHIKV 06.21 in C6/36. First, we assessed that CHIKV replication was not affected by anti-Wolbachia tetracycline treatment, as viral RNA titer was not significantly different between C6/36_TET and C6/36_CTRL cells at MOIs of 0.1 (P = 0.45) and 3 (P = 0.68) (Fig 4). The viral RNA titer increased from 2 h to 72 h post-infection (pi), with a short eclipse phase between 8 h and 10 h pi, then decreased until 96 h to reach a plateau until day 7 pi. The viral replication was dramatically reduced in C6/36_wAlbB compared to C6/36_TET cells as measured by RT-qPCR after infection at MOI 0.1 (Fig 5A). The RNA titer significantly decreased in C6/36_wAlbB cells by at least ten-fold across all time-points. Interestingly, Wolbachia-mediated inhibition depended on the time of infection (Wolbachia*time interaction, P<2E-16), suggesting that presence of Wolbachia could delay virus replication as previously mentioned [43]. Although viral RNA titer decreased, inhibition was not complete with at least 4.81 log10 CHIKV RNA copies per ng total RNA in C6/36_wAlbB cells at day 1 pi, where Wolbachia antiviral effect seemed to be the strongest. CHIKV inhibition by wAlbB was also measured at the RNA infectious particles level using FFA assay on cell supernatants (Fig 5B). A major decrease of viral infectious titer was detected in C6/36_wAlbB compared to C6/36_TET cells, depending on the time post-infection (Wolbachia*time interaction, P = 0.00177). As for viral RNA, this suggests that Wolbachia-mediated inhibition of viral infectious particles production decreases with the time of infection, even if the time effect is lower than for viral RNA decrease. The wAlbB density was monitored in both CHIKV infected (CHIKV+) and uninfected (CHIKV-) cells using qPCR (Fig 6). The bacterial load did not vary according to viral infection (P = 0.228) but time had a significant effect (P<2E-16). The Wolbachia titer increased with time, ranging from 13.3 to 25.7 wsp/actin ratio at day 1 and 7 pi, respectively.

Bottom Line: To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain.Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB.More broadly, this put into question the ecological role of Wolbachia symbiont in Ae. albopictus, but also the ability of the CHIKV to counteract Wolbachia's antiviral potential in vivo.

View Article: PubMed Central - PubMed

Affiliation: Université de Lyon, UMR5557 Ecologie Microbienne, CNRS, USC1190 INRA, VetAgro Sup, Université Lyon 1, Villeurbanne, France.

ABSTRACT
Wolbachia, a widespread endosymbiont of terrestrial arthropods, can protect its host against viral and parasitic infections, a phenotype called "pathogen blocking". However, in some cases Wolbachia may have no effect or even enhance pathogen infection, depending on the host-Wolbachia-pathogen combination. The tiger mosquito Aedes albopictus is naturally infected by two strains of Wolbachia, wAlbA and wAlbB, and is a competent vector for different arboviruses such as dengue virus (DENV) and chikungunya virus (CHIKV). Interestingly, it was shown in some cases that Ae. albopictus native Wolbachia strains are able to inhibit DENV transmission by limiting viral replication in salivary glands, but no such impact was measured on CHIKV replication in vivo. To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain. Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB. Using FISH, we observed CHIKV and wAlbB in the same mosquito cells, indicating that the virus is still able to enter the cell in the presence of the bacterium. Further work is needed to decipher molecular pathways involved in Wolbachia-CHIKV interaction at the cellular level, but this cellular model can be a useful tool to study the mechanism behind virus blocking phenotype induced by Wolbachia. More broadly, this put into question the ecological role of Wolbachia symbiont in Ae. albopictus, but also the ability of the CHIKV to counteract Wolbachia's antiviral potential in vivo.

Show MeSH
Related in: MedlinePlus