Biology subjects

Rosales Rosas, A. L.

Publications and source records attributed to Rosales Rosas, A. L..

3 recordsLinked to original sources

bioRxiv2022

Ex vivo midgut cultures of Aedes aegypti are efficiently infected by mosquito-borne alpha- and flaviviruses

Aedes aegypti mosquitoes can transmit several arboviruses, including chikungunya virus (CHIKV), dengue virus (DENV), and Zika virus (ZIKV). When blood-feeding on a virus-infected human, the mosquito ingests the virus into the midgut (stomach), where it replicates and must overcome the midgut barrier to disseminate to other organs and ultimately be transmitted via the saliva. Current tools to study mosquito-borne viruses (MBVs) include 2D-cell culture systems and in vivo mosquito infection models, which offer great advantages, yet have some limitations. Here, we describe a long-term ex vivo culture of Ae. aegypti midguts. Cultured midguts were metabolically active for 7 days in a 96-well plate at 28{degrees}C and were permissive to ZIKV, DENV, Ross River virus (RRV) and CHIKV. Ex vivo midguts from Culex pipiens mosquitoes were found to be permissive to Usutu virus (USUV). Immunofluorescence staining confirmed viral protein synthesis in CHIKV-infected midguts of Ae. aegypti. Furthermore, fluorescence microscopy revealed replication and spread of a reporter DENV in specific regions of the midgut. In addition, two known antiviral molecules, {beta}-D-N4-hydroxycytidine (NHC) and 7-deaza-2-C-methyladenosine (7DMA), were able to inhibit CHIKV and ZIKV replication, respectively, in the ex vivo model. Together, our results show that ex vivo midguts can be efficiently infected with mosquito-borne alpha- and flaviviruses and employed to evaluate antiviral drugs. Furthermore, the setup can be extended to other mosquito species. Ex vivo midgut cultures could thus be a new model to study MBVs, offering the advantage of reduced biosafety measures compared to infecting living mosquitoes. ImportanceMosquito-borne viruses (MBVs) are a significant global health threat since they can cause severe diseases in humans, such as hemorrhagic fever, encephalitis, and chronic arthritis. MBVs rely on the mosquito vector to infect new hosts and perpetuate virus transmission. No therapeutics are currently available. The study of arbovirus infection in the mosquito vector can greatly contribute to elucidating strategies for controlling arbovirus transmission. This work investigated the infection of midguts from Aedes aegypti mosquitoes in an ex vivo platform. We found several MBVs capable of replicating in the midgut tissue, including viruses of major health importance, such as dengue, chikungunya, and Zika viruses. Additionally, antiviral compounds reduced arbovirus infection in the cultured midgut tissue. Overall, the midgut model emerges as a useful tool for diverse applications such as studying tissue-specific responses to virus infection and screening potential anti-arboviral molecules.

molecular biology↗

bioRxiv2022

Biodistribution and Environmental Safety of a Live-attenuated YF17D-vectored SARS-CoV-2 Vaccine Candidate

New platforms are urgently needed for the design of novel prophylactic vaccines and advanced immune therapies. Live-attenuated yellow fever vaccine YF17D serves as vector for several licensed vaccines and platform for novel vaccine candidates. Based on YF17D, we developed YF-S0 as exceptionally potent COVID-19 vaccine candidate. However, use of such live RNA virus vaccines raises safety concerns, i.e., adverse events linked to original YF17D (yellow fever vaccine-associated neurotropic; YEL-AND, and viscerotropic disease; YEL-AVD). In this study, we investigated the biodistribution and shedding of YF-S0 in hamsters. Likewise, we introduced hamsters deficient in STAT2 signaling as new preclinical model of YEL-AND/AVD. Compared to parental YF17D, YF-S0 showed an improved safety with limited dissemination to brain and visceral tissues, absent or low viremia, and no shedding of infectious virus. Considering yellow fever virus is transmitted by Aedes mosquitoes, any inadvertent exposure to the live recombinant vector via mosquito bites is to be excluded. The transmission risk of YF-S0 was hence evaluated in comparison to readily transmitting YFV-Asibi strain and non-transmitting YF17D vaccine, with no evidence for productive infection of vector mosquitoes. The overall favorable safety profile of YF-S0 is expected to translate to other novel vaccines that are based on the same YF17D platform.

microbiology↗

bioRxiv2020

Establishment of Culex modestus in Belgium and a glance into the virome of Belgian mosquito species

Culex modestus mosquitoes are known transmission vectors of West Nile virus and Usutu virus. Their presence has been reported across several European countries, including only one larva confirmed in Belgium in 2018. Mosquitoes were collected in the city of Leuven and surroundings in the summer of 2019 and 2020. Species identification was performed based on morphological features and partial sequences of the mitochondrial cytochrome oxidase subunit 1 (COI) gene. The 107 mosquitoes collected in 2019 belonged to eight mosquito species: Cx. pipiens (24.3%), Cx. modestus (48.6%), Cx. torrentium (0.9%), Culiseta annulata (0.9%), Culiseta morsitans (0.9%), Ae. sticticus (14.0%), Ae. cinereus (9.3%) and Anopheles plumbeus (0.9%), suggesting the presence of an established Cx. modestus population in Belgium. Collection of Cx. modestus mosquitoes at the same locations in 2020, confirmed the establishment in the region. Haplotype network analysis of the COI sequences for Cx. modestus showed that the Belgian population is rather diverse, suggesting that it may have been established in Belgium for some time. The Belgian Cx. modestus population was most closely related to populations from the UK and Germany. Characterization of the virome of the collected mosquitoes resulted in the identification of at least 33 eukaryotic viral species. Nine (near-) complete genomes belonging to 6 viral species were identified, all of which were closely related to known viruses. In conclusion, we here report the presence of Cx. modestus in the surroundings of Leuven, Belgium. As this species is known to be a vector of several arboviruses, the implementation of vector surveillance programs monitoring this species is recommended. ImportanceCulex modestus is a mosquito species that plays a role as a bridge vector, being able to transmit pathogens between birds, as well as from birds to mammals, including humans. In Belgium, this mosquito species was considered absent, until the finding of one larva in 2018 and subsequent evidence of a large population in 2019-2020 described here. We collected mosquitoes in the summer of 2019 and 2020 in the city of Leuven and surroundings. The mosquito species was identified by morphological and molecular methods, demonstrating the presence of Cx. modestus in this region. The ability of mosquitoes to transmit pathogens can depend on several factors, one of them being their natural virus composition. Therefore, we identified the mosquito-specific viruses harboured by Belgian mosquitoes. As Cx. modestus is able to transmit viruses such as West Nile virus and Usutu virus, the establishment of this mosquito species may increase the risk of virus transmission in the region. It is thus advisable to implement mosquito surveillance programs monitoring this species.

microbiology↗