High-Resolution Proteomics Unveils Salivary Gland Disruption and Saliva-Hemolymph Protein Exchange in -Infected Mosquitoes.

sporozoites, the stage that initiates a malaria infection, must invade the mosquito salivary glands (SGs) before transmitting to a vertebrate host. However, the effects of sporozoite invasion on salivary gland physiology and saliva composition remain largely unexplored. We examined the impact of infection on salivary glands using high-resolution proteomics, gene expression, and morphological analysis.

Identification of a dengue 2 virus envelope protein receptor in critical for viral midgut infection.

The establishment of a productive dengue virus (DENV) infection in the midgut epithelial cells of is critical for the viral transmission cycle. The hypothesis that DENV virions interact directly with specific mosquito midgut proteins was explored. We found that DENV serotype 2 (DENV2) pretreated with trypsin interacted with a single 31 kDa protein, identified as AAEL011180 by protein mass spectrometry.

Exploring the transcriptome of immature stages of Ornithodoros hermsi, the soft-tick vector of tick-borne relapsing fever.

Blood-feeding behavior has independently evolved in arthropods multiple times. Unlike hard ticks, soft ticks employ a rapid-feeding strategy for hematophagy, and there are comparatively limited studies on the transcriptomes of these organisms. This study investigates the soft tick Ornithodoros hermsi, conducting histopathological examinations at bitten skin sites and tick whole-body transcriptomic analyses across various developmental and feeding stages, including larvae, 1st-nymphal, and 2nd-nymphal stages.

Exploring dose-response relationships in Aedes aegypti survival upon bacteria and arbovirus infection.

A detailed understanding of how host fitness changes in response to variations in microbe density (an ecological measure of disease tolerance) is an important aim of infection biology. Here, we applied dose-response curves to study Aedes aegypti survival upon exposure to different microbes. We challenged female mosquitoes with Listeria monocytogenes, a model bacterial pathogen, Dengue 4 virus and Zika virus, two medically relevant arboviruses, to understand the distribution of mosquito survival following microbe exposure.

The Aedes aegypti peritrophic matrix controls arbovirus vector competence through HPx1, a heme-induced peroxidase.

Aedes aegypti mosquitoes are the main vectors of arboviruses. The peritrophic matrix (PM) is an extracellular layer that surrounds the blood bolus. It acts as an immune barrier that prevents direct contact of bacteria with midgut epithelial cells during blood digestion.

Hemocyte differentiation to the megacyte lineage enhances mosquito immunity against .

Activation of signaling in by silencing , a suppressor of this pathway, enhances local release of hemocyte-derived microvesicles (HdMv), promoting activation of the mosquito complement-like system, which eliminates ookinetes. We uncovered the mechanism of this immune enhancement. silencing triggers a -mediated differentiation of granulocytes to the megacyte lineage, a new subpopulation of giant cells, resulting in a dramatic increase in the proportion of circulating megacytes.

Zika virus infection drives epigenetic modulation of immunity by the histone acetyltransferase CBP of Aedes aegypti.

Epigenetic mechanisms are responsible for a wide range of biological phenomena in insects, controlling embryonic development, growth, aging and nutrition. Despite this, the role of epigenetics in shaping insect-pathogen interactions has received little attention. Gene expression in eukaryotes is regulated by histone acetylation/deacetylation, an epigenetic process mediated by histone acetyltransferases (HATs) and histone deacetylases (HDACs).

Non-immune Traits Triggered by Blood Intake Impact Vectorial Competence.

Blood-feeding arthropods are considered an enormous public health threat. They are vectors of a plethora of infectious agents that cause potentially fatal diseases like Malaria, Dengue fever, Leishmaniasis, and Lyme disease. These vectors shine due to their own physiological idiosyncrasies, but one biological aspect brings them all together: the requirement of blood intake for development and reproduction.

Prostaglandins regulate humoral immune responses in Aedes aegypti.

Prostaglandins (PGs) are immuno-active lipids that mediate the immune response in invertebrates and vertebrates. In insects, PGs play a role on different physiological processes such as reproduction, ion transport and regulation of cellular immunity. However, it is unclear whether PGs play a role in invertebrate's humoral immunity, and, if so, which immune signaling pathways would be modulated by PGs.

Unlike Zika, Chikungunya virus interferes in the viability of Aedes aegypti eggs, regardless of females' age.

Chikungunya and Zika are arboviruses transmitted by the mosquito Aedes aegypti. Mosquito fecundity and egg viability are important parameters of vectorial capacity. Here we aim to understand, comparatively, the effects of Chikungunya virus (CHIKV) and Zika virus (ZIKV) infections on the fecundity and fertility of young and old Aedes aegypti females.

Natural infection by the protozoan Leptomonas wallacei impacts the morphology, physiology, reproduction, and lifespan of the insect Oncopeltus fasciatus.

Trypanosomatids are protozoan parasites that infect thousands of globally dispersed hosts, potentially affecting their physiology. Several species of trypanosomatids are commonly found in phytophagous insects. Leptomonas wallacei is a gut-restricted insect trypanosomatid only retrieved from Oncopeltus fasciatus.

Non-canonical transcriptional regulation of heme oxygenase in Aedes aegypti.

Heme oxygenase (HO) is a ubiquitous enzyme responsible for heme breakdown, which yields carbon monoxide (CO), biliverdin (BV) and ferrous ion. Here we show that the Aedes aegypti heme oxygenase gene (AeHO - AAEL008136) is expressed in different developmental stages and tissues. AeHO expression increases after a blood meal in the midgut, and its maximal transcription levels overlaps with the maximal rate of the further modified A.

Regulation of midgut cell proliferation impacts Aedes aegypti susceptibility to dengue virus.

Aedes aegypti is the vector of some of the most important vector-borne diseases like dengue, chikungunya, zika and yellow fever, affecting millions of people worldwide. The cellular processes that follow a blood meal in the mosquito midgut are directly associated with pathogen transmission. We studied the homeostatic response of the midgut against oxidative stress, as well as bacterial and dengue virus (DENV) infections, focusing on the proliferative ability of the intestinal stem cells (ISC).

The redox-sensing gene affects intestinal homeostasis, insecticide resistance, and Zika virus susceptibility in the mosquito .

Production and degradation of reactive oxygen species (ROS) are extensively regulated to ensure proper cellular responses to various environmental stimuli and stresses. Moreover, physiologically generated ROS function as secondary messengers that can influence tissue homeostasis. The cap'n'collar transcription factor known as nuclear factor erythroid-derived factor 2 (Nrf2) coordinates an evolutionarily conserved transcriptional activation pathway that mediates antioxidant and detoxification responses in many animal species, including insects and mammals.

Amino acid metabolic signaling influences Aedes aegypti midgut microbiome variability.

The mosquito midgut microbiota has been shown to influence vector competence for multiple human pathogens. The microbiota is highly variable in the field, and the sources of this variability are not well understood, which limits our ability to understand or predict its effects on pathogen transmission. In this work, we report significant variation in female adult midgut bacterial load between strains of A.

Catalase protects Aedes aegypti from oxidative stress and increases midgut infection prevalence of Dengue but not Zika.

Background: Digestion of blood in the midgut of Aedes aegypti results in the release of pro-oxidant molecules that can be toxic to the mosquito. We hypothesized that after a blood meal, the antioxidant capacity of the midgut is increased to protect cells against oxidative stress. Concomitantly, pathogens present in the blood ingested by mosquitoes, such as the arboviruses Dengue and Zika, also have to overcome the same oxidative challenge, and the antioxidant program induced by the insect is likely to influence infection status of the mosquito and its vectorial competence.

Microbiota activates IMD pathway and limits Sindbis infection in Aedes aegypti.

Background: Aedes aegypti is the main vector of important arboviruses such as dengue, Zika and chikungunya. During infections mosquitoes can activate the immune pathways Toll, IMD and JAK/STAT to limit pathogen replication.

Results: Here, we evaluate the immune response profile of Ae.

The DNA chaperone HMGB1 potentiates the transcriptional activity of Rel1A in the mosquito Aedes aegypti.

High Mobility Group protein 1 (HMGB1) is a non-histone, chromatin-associated nuclear protein that functions in regulating eukaryotic gene expression. We investigated the influence and mechanism of action of Aedes aegypti HMGB1 (AaHMGB1) on mosquito Rel1A-mediated transcription from target gene promoters. The DNA-binding domain (RHD) of AaRel1A was bacterially expressed and purified, and AaHMGB1 dramatically enhanced RHD binding to consensus NF-kB/Rel DNA response elements.

The use of a chemically defined artificial diet as a tool to study Aedes aegypti physiology.

Aedes aegypti mosquitoes obtain from vertebrate blood nutrients that are essential to oogenesis, such as proteins and lipids. As with all insects, mosquitoes do not synthesize cholesterol but take it from the diet. Here, we used a chemically defined artificial diet, hereafter referred to as Substitute Blood Meal (SBM), that was supplemented with cholesterol to test the nutritional role of cholesterol.

Heme Signaling Impacts Global Gene Expression, Immunity and Dengue Virus Infectivity in Aedes aegypti.

Blood-feeding mosquitoes are exposed to high levels of heme, the product of hemoglobin degradation. Heme is a pro-oxidant that influences a variety of cellular processes. We performed a global analysis of heme-regulated Aedes aegypti (yellow fever mosquito) transcriptional changes to better understand influence on mosquito physiology at the molecular level.