Onyango, M. G. | bioRxiv Science

bioRxiv2023

Multi-Omics Analysis Of Antiviral Interactions Of Elizabethkingia anophelis And Zika Virus

BackgroundThe microbial communities residing in the mosquito midgut play a key role in determining the outcome of mosquito pathogen infection. Elizabethkingia anophelis, originally isolated from the midgut of Anopheles gambiae, has drawn much attention due to its close association with Aedes and Anopheles mosquitoes, primary vectors of dengue virus and malaria parasites, respectively. E. anophelis possesses a broad-spectrum antiviral phenotype, yet a gap in knowledge regarding the mechanistic basis of its interaction with viruses exists. Methodology/Principal findingsTo further understand the antiviral interactions between E. anophelis and Zika virus (ZIKV), we utilized a non-targeted multi-omics approach, analyzing lipids, proteins, and metabolites of cell monolayers co-infected with ZIKV and E. anophelis. We further assessed the gene expression of ZIKV when cultured in the presence of E. anophelis. ZIKV cultured in the presence of E. anophelis resulted in an attenuated replicative fitness and unproductive virus infection. Further, in this treatment, we observed lower levels of the nonstructural protein 5 (NS5) and RNA-directed RNA polymerase (RdRp) protein. Lastly, a significant decrease in arginine levels, an essential requirement for viral replication and progression of viral infection was observed. Conclusions/SignificanceThis study provides insights into the molecular basis of E. anophelis antiviral phenotype. These findings improve our knowledge of how microbes and viruses interact to impact viral replication. In the future, our findings can be utilized to unravel the mechanism behind the antiviral phenotype of E. anophelis, and this can help develop novel paradigms for viral therapeutics. AUTHOR SUMMARYZika is a re-emerging disease and is endemic in many regions of sub-Saharan Africa, Asia and Latin America. It remains a major public health threat and lacks FDA-approved therapeutics or vaccines, hence the urgent need for the identification of alternative approaches that limit the transmission of the pathogens by its primary vector, Aedes spp. The microbial communities residing in the mosquito midgut play a key role in determining the outcome of mosquito pathogen infection. Flavobacteria dominates the mosquito midgut including Elizabethkingia, which is a gram-negative bacillus prevalent in Aedes and Anopheles species of mosquitoes. E. anophelis, a poorly studied midgut microbe, has a broad-spectrum antiviral phenotype, yet the mechanism of its antiviral action is unknown. In this study, we have identified several pathways as well as Zika virus proteins perturbed when the Zika virus is cultivated in the presence of E. anophelis. Our findings do not only provide insights into microbial, virus interaction but could be harnessed to develop novel antiviral tools.

microbiology↗

bioRxiv2019

Spatio-temporal distribution of Spiroplasma infections in the tsetse fly (Glossina fuscipes fuscipes) in northern Uganda

Tsetse flies (Glossina spp.) are vectors of parasitic trypanosomes, which cause human (HAT) and animal African trypanosomiasis (AAT) in sub-Saharan Africa. In Uganda, Glossina fuscipes fuscipes (Gff) is the main vector of HAT, where it transmits Gambiense disease in the northwest and Rhodesiense disease in central, southeast and western regions. Endosymbionts can influence transmission efficiency of parasites through their insect vectors via conferring a protective effect against the parasite. It is known that the bacterium Spiroplasma is capable of protecting its Drosophila host from infection with a parasitic nematode. This endosymbiont can also impact its hosts population structure via altering host reproductive traits. Here, we used field collections across 26 different Gff sampling sites in northern and western Uganda to investigate the association of Spiroplasma with geographic origin, seasonal conditions, Gff genetic background and sex, and trypanosome infection status. We also investigated the influence of Spiroplasma on Gff vector competence to trypanosome infections under laboratory conditions.\n\nGeneralized linear models (GLM) showed that Spiroplasma probability was correlated with the geographic origin of Gff host and with the season of collection, with higher prevalence found in flies within the Albert Nile (0.42 vs 0.16) and Achwa River (0.36 vs 0.08) watersheds and with higher prevalence detected in flies collected in the intermediate than wet season. In contrast, there was no significant correlation of Spiroplasma prevalence with Gff host genetic background or sex once geographic origin was accounted for in generalized linear models. Additionally, we found a potential negative correlation of Spiroplasma with trypanosome infection, with only 2% of Spiroplasma infected flies harboring trypanosome co-infections. We also found that in a laboratory line of Gff, parasitic trypanosomes are less likely to colonize the midgut in individuals that harbor Spiroplasma infection. These results indicate that Spiroplasma infections in tsetse may be maintained by not only maternal but also via horizontal transmission routes, and Spiroplasma infections may also have important effects on trypanosome transmission efficiency of the host tsetse. Potential functional effects of Spiroplasma infection in Gff could have impacts on vector control approaches to reduce trypanosome infections.\n\nAuthor SummaryWe investigated the association of symbiotic Spiroplasma with the tsetse fly host Glossina fuscipes fuscipes (Gff) to assess if Spiroplasma infections are correlated with Gff genetic background, geography, or season and its interaction with trypanosome parasites. We analyzed distribution and prevalence of Spiroplasma infections across different Gff sampling sites in northern and western Uganda, and found that the symbiont is unevenly distributed and infections have not reached fixation within these sampling sites. We tested for associations with geographic origin of the collections, seasonal environmental conditions at the time of collection, Gff host genetic background and sex, plus trypanosome co-infections. Spiroplasma prevalence was strongly correlated with geographic origin and seasonal environmental conditions. Our parasite infection data suggested a negative correlation of Spiroplasma with trypanosome infection, with only 5 out of 243 flies harboring trypanosome co-infections. We further investigated the influence of Spiroplasma on trypanosome parasite infections in the laboratory. We found that trypanosomes were less likely to establish an infection in Gff individuals that carried Spiroplasma infections. Our results provide new information on host-endosymbiont dynamics in an important human disease vector, and provide evidence that Spiroplasma may confer partial resistance to Gff trypanosome infections. These findings provide preliminary evidence that a symbiont-based control method could be successful in combating tsetse trypanosome transmission to humans and livestock in sub-Saharan Africa.

epidemiology↗