A transcriptomic atlas of Aedes aegypti reveals detailed functional organization of major body parts and gut regional specializations in sugar-fed and blood-fed adult females

Mosquito vectors transmit numerous pathogens, but large gaps remain in our understanding of their physiology. To facilitate future explorations of mosquito biology, with specific attention to the major vector Aedes aegypti, we have created Aegypti-Atlas (http://aegyptiatlas.buchonlab.com/), an online resource hosting RNAseq profiles of Ae. aegypti body parts (head, thorax, abdomen, gut, Malpighian tubules, and ovaries), gut regions (crop, proventriculus, anterior and posterior midgut, and hindgut), and a time course of blood meal digestion in the gut. Using Aegypti-Atlas, we provide new insights into the regionalization of gut function, blood feeding response, and immune defenses. We find that the anterior and posterior regions of the mosquito midgut possess clearly delineated digestive specializations which are preserved in the blood-fed state. Blood feeding initiates the sequential transcriptional induction and repression/depletion of multiple cohorts of peptidases throughout blood meal digestion. With respect to defense, immune signaling components, but not recognition or effector molecules, show enrichment in ovaries. Basal expression of antimicrobial peptides is dominated by two genes, holotricin and gambicin, that are expressed in the carcass and the digestive tissues, respectively, in a near mutually exclusive manner. In the midgut, gambicin and other immune effector genes are almost exclusively expressed in the anterior regions, while the posterior midgut exhibits the hallmarks of immune tolerance. Finally, in a cross-species comparison between the midguts of Ae. aegypti and Anopheles gambiae, we observe that regional digestive and immune specializations are closely conserved, indicating that our data may yield inferences that are broadly relevant to multiple mosquito vector species. We further demonstrate that the expression of orthologous genes is highly correlated, with the exception of a ‘species signature’ comprising a small number of highly/disparately expressed genes. With this work, we show the potential of Aegypti-Atlas to unlock a more complete understanding of mosquito biology.

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Sequential Infection of Aedes aegypti Mosquitoes with Chikungunya Virus and Zika Virus Enhances Early Zika Virus Transmission

Insects ◽

10.3390/insects9040177 ◽

2018 ◽

Vol 9 (4) ◽

pp. 177 ◽

Cited By ~ 12

Author(s):

Tereza Magalhaes ◽

Alexis Robison ◽

Michael Young ◽

William Black ◽

Brian Foy ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Zika Virus ◽

Chikungunya Virus ◽

Vector Competence ◽

Virus Transmission ◽

Mosquito Vector ◽

Molecular Aspects ◽

Virus Interactions ◽

Sequential Infection

In urban settings, chikungunya, Zika, and dengue viruses are transmitted by Aedes aegypti mosquitoes. Since these viruses co-circulate in several regions, coinfection in humans and vectors may occur, and human coinfections have been frequently reported. Yet, little is known about the molecular aspects of virus interactions within hosts and how they contribute to arbovirus transmission dynamics. We have previously shown that Aedes aegypti exposed to chikungunya and Zika viruses in the same blood meal can become coinfected and transmit both viruses simultaneously. However, mosquitoes may also become coinfected by multiple, sequential feeds on single infected hosts. Therefore, we tested whether sequential infection with chikungunya and Zika viruses impacts mosquito vector competence. We exposed Ae. aegypti mosquitoes first to one virus and 7 days later to the other virus and compared infection, dissemination, and transmission rates between sequentially and single infected groups. We found that coinfection rates were high after sequential exposure and that mosquitoes were able to co-transmit both viruses. Surprisingly, chikungunya virus coinfection enhanced Zika virus transmission 7 days after the second blood meal. Our data demonstrate heterologous arbovirus synergism within mosquitoes, by unknown mechanisms, leading to enhancement of transmission under certain conditions.

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Confocal Analysis of the Distribution and Persistence of Sindbis Virus (TaV-GFP) Infection in Midguts of Aedes aegypti Mosquitoes

Microscopy and Microanalysis ◽

10.1017/s1431927620001270 ◽

2020 ◽

Vol 26 (2) ◽

pp. 267-274

Author(s):

Jason J. Saredy ◽

Florence Y. Chim ◽

Zoë L. Lyski ◽

Yani P. Ahearn ◽

Doria F. Bowers

Keyword(s):

Aedes Aegypti ◽

Sindbis Virus ◽

Fluorescent Protein ◽

Blood Feeding ◽

Target Tissue ◽

Secondary Target ◽

Posterior Midgut ◽

Infected Cells ◽

Green Fluorescent ◽

Global Threat

AbstractBiological transmission of arthropod-borne viruses (arboviruses) to vertebrate hosts by hematophagous insects poses a global threat because such arboviruses can result in a range of serious public health infectious diseases. Sindbis virus (SINV), the prototype Alphavirus, was used to track infections in the posterior midgut (PMG) of Aedes aegypti adult mosquitoes. Females were fed viremic blood containing a virus reporter, SINV [Thosea asigna virus-green fluorescent protein (TaV-GFP)], that leaves a fluorescent signal in infected cells. We assessed whole-mount PMGs to identify primary foci, secondary target tissues, distribution, and virus persistence. Following a viremic blood meal, PMGs were dissected and analyzed at various days of post blood-feeding. We report that virus foci indicated by GFP in midgut epithelial cells resulted in a 9.8% PMG infection and a 10.8% dissemination from these infected guts. The number of virus foci ranged from 1 to 3 per individual PMG and was more prevalent in the PMG-middle > PMG-frontal > PMG-caudal regions. SINV TaV-GFP was first observed in the PMG (primary target tissue) at 3 days post blood-feeding, was sequestered in circumscribed foci, replicated in PMG peristaltic muscles (secondary target tissue) following dissemination, and GFP was observed to persist in PMGs for 30 days postinfection.

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Serine hydroxymethyltransferase controls blood-meal digestion in the midgut of Aedes aegypti mosquitoes

Parasites & Vectors ◽

10.1186/s13071-019-3714-2 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Xuemei Li ◽

Jinyu Yang ◽

Qian Pu ◽

Xinyue Peng ◽

Lili Xu ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Digestive Enzymes ◽

Egg Production ◽

Sequence Similarity ◽

Mrna Level ◽

Serine Hydroxymethyltransferase ◽

Blood Protein ◽

Transcriptional Expression ◽

Blood Meal Digestion

Abstract Background Female Aedes aegypti mosquitoes are vectors of arboviruses that cause diverse diseases of public health significance. Blood protein digestion by midgut proteases provides anautogenous mosquitoes with the nutrients essential for oocyte maturation and egg production. Midgut-specific miR-1174 affects the functions of the midgut through its target gene serine hydroxymethyltransferase (SHMT). However, less is known about SHMT-regulated processes in blood digestion by mosquitoes. Methods RNAi of SHMT was realized by injection of the double-stranded RNA at 16 h post-eclosion. The expression of SHMT at mRNA level and protein level was assayed by real-time PCR and Western blotting, respectively. Statistical analyses were performed with GraphPad7 using Student’s t-test. Results Here, we confirmed that digestion of blood was inhibited in SHMT RNAi-silenced female A. aegypti mosquitoes. Evidence is also presented that all SHMT-depleted female mosquitoes lost their flight ability and died within 48 h of a blood meal. Furthermore, most examined digestive enzymes responded differently in their transcriptional expression to RNAi depletion of SHMT, with some downregulated, some upregulated and some remaining stable. Phylogenetic analysis showed that transcriptional expression responses to SHMT silence were largely unrelated to the sequence similarity between these enzymes. Conclusions Overall, this research shows that SHMT was expressed at a low level in the midgut of Aedes aegypti mosquitoes, but blood-meal digestion was inhibited when SHMT was silenced. Transcriptional expressions of different digestive enzymes were affected in response to SHMT depletion, suggesting that SHMT is required for the blood-meal digestion in the midgut and targeting SHMT could provide an effective strategy for vector mosquito population control.

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Ultrastructural changes in posterior midgut cells associated with blood feeding in adult female Rhodnius prolixus Stal (Hemiptera: Reduviidae)

Canadian Journal of Zoology ◽

10.1139/z83-339 ◽

1983 ◽

Vol 61 (11) ◽

pp. 2574-2586 ◽

Cited By ~ 57

Author(s):

P. F. Billingsley ◽

A. E. R. Downe

Keyword(s):

Endoplasmic Reticulum ◽

Rough Endoplasmic Reticulum ◽

Blood Meal ◽

Apical Cell ◽

Blood Feeding ◽

Rhodnius Prolixus ◽

Ultrastructural Changes ◽

Dense Matrix ◽

Apical Surface ◽

Posterior Midgut

Modifications of posterior midgut cells of Rhodnius prolixus following a meal of rabbit blood are described. Prominent stacks and whorls of rough endoplasmic reticulum become redistributed following a blood meal but later reform during the postfeeding period. Lysosomes undergo internal structural changes and apparent fluctuations in their number per cell as a result of blood meal ingestion. Before blood feeding, the apical surface of the midgut cells show a typical arrangement of a plasma membrane covered on the lumenal surface by a glycocalyx. After a blood meal, a more complex organisation appears, consisting of two plasma membranes separated by an electron-dense matrix. The lumenal apical membrane proliferates during the digestion period to form loosely organised extracellular membrane layers which may function as a peritrophic membrane. Changes in the rough endoplasmic reticulum and lysosomes and modifications to the apical cell surface appear to coincide with previously described proteinase activity cycles in the posterior midgut of R. prolixus. The implications of these results are discussed and are compared with similar ultrastructural events from haematophagous Diptera.

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On the use of inhibitors of 4-hydroxyphenylpyruvate dioxygenase as a vector-selective insecticide in the control of mosquitoes

10.1101/669747 ◽

2019 ◽

Author(s):

Marlon A. V. Ramirez ◽

Marcos Sterkel ◽

Ademir de Jesus Martins ◽

José Bento Pereira Lima ◽

Pedro L. Oliveira

Keyword(s):

Amino Acids ◽

Body Weight ◽

Aedes Aegypti ◽

Blood Meal ◽

Mosquito Control ◽

Blood Feeding ◽

Degradation Pathway ◽

Cross Resistance ◽

Single Meal ◽

Neurotoxic Insecticides

AbstractBlood-sucking insects incorporate many times their body weight of blood in a single meal. As proteins are the major component of vertebrate blood, its digestion in the gut of hematophagous insects generates extremely high concentrations of free amino acids. Previous reports showed that the tyrosine degradation pathway plays an essential role in adapting these animals to blood feeding. Inhibiting 4-hydroxyphenylpyruvate dioxygenase (HPPD), the rate-limiting step of tyrosine degradation, results in the death of insects after a blood meal. Therefore, it was suggested that compounds that block the catabolism of tyrosine could act selectively on blood-feeding insects. Here we have evaluated the toxicity against mosquitoes of three HPPD inhibitors currently used as herbicides and in human health. Among the compounds tested, nitisinone (NTBC) proved to be more potent than mesotrione (MES) and isoxaflutole (IFT) in Aedes aegypti. NTBC was lethal to Ae. aegypti in artificial feeding assays (LD50: 4.36 µM), as well as in topical application (LD50: 0.0033 nmol/mosquito). NTBC was also lethal to Ae. aegypti populations that were resistant to neurotoxic insecticides, and it was lethal to other mosquito species (Anopheles and Culex). Therefore, HPPD inhibitors, particularly NTBC, represent promising new drugs for mosquito control. Since they only affect blood-feeding organisms, they would represent a safer and more environmentally friendly alternative to conventional neurotoxic insecticides.Author SummaryThe control of mosquitoes has been pursued in the last decades by the use of neurotoxic insecticides to prevent the spreading of dengue, zika and malaria, among other diseases. However, the selection and propagation of different mechanisms of resistance hinder the success of these compounds. New methodologies are needed for their control. Hematophagous arthropods, including mosquitoes, ingest quantities of blood that represent many times their body weight in a single meal, releasing huge amounts of amino acids during digestion. Recent studies showed that inhibition of the tyrosine catabolism pathway could be a new selective target for vector control. Thus we tested three different inhibitors of the second enzyme in the tyrosine degradation pathway as tools for mosquito control. Results showed that Nitisinone (NTBC), an inhibitor used in medicine, was the most potent of them. NTBC was lethal to Aedes aegypti when it was administered together with the blood meal and when it was topically applied. It also caused the death of Anopheles aquasalis and Culex quinquefasciatus mosquitoes, as well as field-collected Aedes populations resistant to neurotoxic insecticides, indicating that there is no cross-resistance. We discuss the possible use of NTBC as a new insecticide.

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Assessing the blood-host plasticity and dispersal rate of the malaria vector Anopheles coluzzii

10.1101/424051 ◽

2018 ◽

Cited By ~ 1

Author(s):

James Orsborne ◽

Luis Furuya-Kanamori ◽

Claire L. Jeffries ◽

Mojca Kristan ◽

Abdul Rahim Mohammed ◽

...

Keyword(s):

Blood Meal ◽

Disease Transmission ◽

Blood Feeding ◽

Host Choice ◽

Anopheles Coluzzii ◽

Dispersal Rate ◽

Blood Digestion ◽

Novel Method ◽

Blood Meal Digestion ◽

Blood Meals

AbstractDifficulties with observing the dispersal of insect vectors in the field have hampered understanding of several aspects of their behaviour linked to disease transmission. Here, a novel method based on detection of blood-meal sources is introduced to inform two critical and understudied mosquito behaviours: plasticity in the malaria vector’s blood-host choice and vector dispersal. Strategically located collections of Anopheles coluzzii from a malaria-endemic village of southern Ghana showed statistically significant variation in host species composition of mosquito blood-meals. Trialling a new sampling approach gave the first estimates for the remarkably local spatial scale across which host choice is plastic. Using quantitative PCR, the blood-meal digestion was then quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. We demonstrate how this new ‘molecular Sella score’ approach can be used to estimate the dispersal rate of blood-feeding vectors caught in the field.

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Laboratory colonization by Dirofilaria immitis alters the microbiome of female Aedes aegypti mosquitoes

10.21203/rs.2.23991/v6 ◽

2020 ◽

Author(s):

Abdulsalam Adegoke ◽

Erik Neff ◽

Amie Geary ◽

Montana Ciara Husser ◽

Kevin Wilson ◽

...

Keyword(s):

Aedes Aegypti ◽

Dirofilaria Immitis ◽

Mosquito Species ◽

Bacterial Species ◽

Klebsiella Oxytoca ◽

Variable Region ◽

Blood Feeding ◽

Mosquito Vector ◽

Filarial Nematodes ◽

The Impact

Abstract Background: The ability of blood feeding arthropods to successfully acquire and transmit pathogens of medical and veterinary importance has been shown to be interfered with, or enhanced by, the arthropod’s native microbiome. Mosquitoes transmit viruses, protozoan and filarial nematodes, the majority of which contribute to the 17% of infectious disease cases worldwide. Dirofilaria immitis , a mosquito transmitted by filarial nematodes of dogs and cats, is vectored by several mosquito species including Aedes aegypti . Methods: In this study, we investigated the impact of D. immitis colonization on the microbiome of laboratory reared female A. aegypti . Metagenomic analysis of the V3-V4 variable region of the microbial 16SRNA was used for identification of the microbial differences down to species level. Results We generated a total of 1068 OTUs representing 16 phyla, 181 genera and 271 bacterial species. Overall, in order of abundance, Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were the most represented phylum with D. immitis infected mosquitoes having more of Proteobacteria (71%) than uninfected mosquitoes (56.9%). An interesting finding in this study is the detection of Klebsiella oxytoca in relatively similar abundance in infected and uninfected mosquitoes, suggesting a possible endosymbiotic relationship, and has been previously shown to indirectly compete for nutrients with fungi on domestic housefly eggs and larva. While D. immitis colonization has no effect on the overall species richness, we identified significant differences in the composition of selected bacteria genus and phylum between the two groups. We also reported distinct compositional and phylogenetic differences in the individual bacteria species when commonly identified bacteria were compared. Conclusions In conclusion, this is the first study to the best of our knowledge to understand the impact of a filarial infection on the microbiome of its mosquito vector. Further studies are required to identify bacteria species that could play an important role in the mosquito biology. While the microbiome composition of A. aegypti mosquito have been previously reported, our study shows that in an effort to establish itself, a filarial nematode modifies and alters the overall microbial diversity within its mosquito host.

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Hormone-dependent activation and repression of microRNAs by the ecdysone receptor in the dengue vector mosquito Aedes aegypti

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2102417118 ◽

2021 ◽

Vol 118 (26) ◽

pp. e2102417118

Author(s):

Ya-Zhou He ◽

Emre Aksoy ◽

Yike Ding ◽

Alexander S. Raikhel

Keyword(s):

Aedes Aegypti ◽

Mirna Expression ◽

Blood Meal ◽

Fat Body ◽

Blood Feeding ◽

Small Rna Sequencing ◽

Sequencing Analysis ◽

Ecdysone Receptor ◽

Egg Development ◽

Semialdehyde Dehydrogenase

Female mosquitoes transmit numerous devastating human diseases because they require vertebrate blood meal for egg development. MicroRNAs (miRNAs) play critical roles across multiple reproductive processes in female Aedes aegypti mosquitoes. However, how miRNAs are controlled to coordinate their activity with the demands of mosquito reproduction remains largely unknown. We report that the ecdysone receptor (EcR)–mediated 20-hydroxyecdysone (20E) signaling regulates miRNA expression in female mosquitoes. EcR RNA-interference silencing linked to small RNA-sequencing analysis reveals that EcR not only activates but also represses miRNA expression in the female mosquito fat body, a functional analog of the vertebrate liver. EcR directly represses the expression of clustered miR-275 and miR-305 before blood feeding when the 20E titer is low, whereas it activates their expression in response to the increased 20E titer after a blood meal. Furthermore, we find that SMRTER, an insect analog of the vertebrate nuclear receptor corepressors SMRT and N-CoR, interacts with EcR in a 20E-sensitive manner and is required for EcR-mediated repression of miRNA expression in Ae. aegypti mosquitoes. In addition, we demonstrate that miR-275 and miR-305 directly target glutamate semialdehyde dehydrogenase and AAEL009899, respectively, to facilitate egg development. This study reveals a mechanism for how miRNAs are controlled by the 20E signaling pathway to coordinate their activity with the demands of mosquito reproduction.

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The Mosquito Immune System and the Life of Dengue Virus: What We Know and Do Not Know

Pathogens ◽

10.3390/pathogens8020077 ◽

2019 ◽

Vol 8 (2) ◽

pp. 77 ◽

Cited By ~ 2

Author(s):

Debica Mukherjee ◽

Sandeepan Das ◽

Feroza Begum ◽

Sweety Mal ◽

Upasana Ray

Keyword(s):

Innate Immunity ◽

Immune System ◽

Aedes Aegypti ◽

Dengue Virus ◽

Aedes Albopictus ◽

Blood Meal ◽

Mosquito Vector ◽

Preventive Strategies ◽

Immune Control ◽

The Family

Flaviviruses are largely transmitted to humans by their arthropod vectors such as mosquitoes or ticks. The dengue virus (DENV) is one of the members of the family Flaviviridae and is the causative agent of dengue fever. In the mosquito vector, DENV enters through viremic blood meal and replicates in the mid-gut. Newly formed virion particles circulate to various mosquito organs and get transmitted to the next host in subsequent bites. Aedes aegypti and Aedes albopictus have intricate immune control to allow DENV production at a sub-pathogenic level. In the mosquito, antimicrobial peptides (AMP) and RNA inference (RNAi) are the two main antiviral strategies used against DENV. Apart from innate immunity, mosquito resident microbes play a significant role in modulating DENV replication. In this review, we discuss different immune mechanisms and preventive strategies that act against DENV in two of its vectors: Aedes aegypti and Aedes albopictus.

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Mating and blood-feeding induce transcriptome changes in the spermathecae of the yellow fever mosquito Aedes aegypti

Scientific Reports ◽

10.1038/s41598-020-71904-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Carolina Camargo ◽

Yasir H. Ahmed-Braimah ◽

I. Alexandra Amaro ◽

Laura C. Harrington ◽

Mariana F. Wolfner ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Transcriptional Response ◽

Blood Feeding ◽

Sperm Storage ◽

Biological Processes ◽

Gene Products ◽

Heme Peroxidase ◽

Males And Females

Abstract Aedes aegypti mosquitoes are the primary vectors of numerous viruses that impact human health. As manipulation of reproduction has been proposed to suppress mosquito populations, elucidation of biological processes that enable males and females to successfully reproduce is necessary. One essential process is female sperm storage in specialized structures called spermathecae. Aedes aegypti females typically mate once, requiring them to maintain sperm viably to fertilize eggs they lay over their lifetime. Spermathecal gene products are required for Drosophila sperm storage and sperm viability, and a spermathecal-derived heme peroxidase is required for long-term Anopheles gambiae fertility. Products of the Ae. aegypti spermathecae, and their response to mating, are largely unknown. Further, although female blood-feeding is essential for anautogenous mosquito reproduction, the transcriptional response to blood-ingestion remains undefined in any reproductive tissue. We conducted an RNAseq analysis of spermathecae from unfed virgins, mated only, and mated and blood-fed females at 6, 24, and 72 h post-mating and identified significant differentially expressed genes in each group at each timepoint. A blood-meal following mating induced a greater transcriptional response in the spermathecae than mating alone. This study provides the first view of elicited mRNA changes in the spermathecae by a blood-meal in mated females.

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