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1.
PLoS Pathog ; 10(10): e1004398, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25340821

RESUMO

Plasmodium and dengue virus, the causative agents of the two most devastating vector-borne diseases, malaria and dengue, are transmitted by the two most important mosquito vectors, Anopheles gambiae and Aedes aegypti, respectively. Insect-bacteria associations have been shown to influence vector competence for human pathogens through multi-faceted actions that include the elicitation of the insect immune system, pathogen sequestration by microbes, and bacteria-produced anti-pathogenic factors. These influences make the mosquito microbiota highly interesting from a disease control perspective. Here we present a bacterium of the genus Chromobacterium (Csp_P), which was isolated from the midgut of field-caught Aedes aegypti. Csp_P can effectively colonize the mosquito midgut when introduced through an artificial nectar meal, and it also inhibits the growth of other members of the midgut microbiota. Csp_P colonization of the midgut tissue activates mosquito immune responses, and Csp_P exposure dramatically reduces the survival of both the larval and adult stages. Ingestion of Csp_P by the mosquito significantly reduces its susceptibility to Plasmodium falciparum and dengue virus infection, thereby compromising the mosquito's vector competence. This bacterium also exerts in vitro anti-Plasmodium and anti-dengue activities, which appear to be mediated through Csp_P -produced stable bioactive factors with transmission-blocking and therapeutic potential. The anti-pathogen and entomopathogenic properties of Csp_P render it a potential candidate for the development of malaria and dengue control strategies.


Assuntos
Anopheles/microbiologia , Chromobacterium/metabolismo , Vírus da Dengue , Infecções por Bactérias Gram-Negativas/metabolismo , Malária/microbiologia , Animais , Culicidae , Vetores Genéticos/genética , Humanos , Técnicas In Vitro , Plasmodium falciparum/microbiologia , Fatores de Virulência
2.
Proc Natl Acad Sci U S A ; 109(22): 8699-704, 2012 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-22589302

RESUMO

The mechanisms underlying tumor dormancy have been elusive and not well characterized. We recently published an experimental model for the study of human tumor dormancy and the role of angiogenesis, and reported that the angiogenic switch was preceded by a local increase in VEGF-A and basic fibroblast growth factor. In this breast cancer xenograft model (MDA-MB-436 cells), analysis of differentially expressed genes revealed that heat shock protein 27 (HSP27) was significantly up-regulated in angiogenic cells compared with nonangiogenic cells. The effect of HSP27 down-regulation was further evaluated in cell lines, mouse models, and clinical datasets of human patients with breast cancer and melanoma. Stable down-regulation of HSP27 in angiogenic tumor cells was followed by long-term tumor dormancy in vivo. Strikingly, only 4 of 30 HSP27 knockdown xenograft tumors initiated rapid growth after day 70, in correlation with a regain of HSP27 protein expression. Significantly, no tumors escaped from dormancy without HSP27 expression. Down-regulation of HSP27 was associated with reduced endothelial cell proliferation and decreased secretion of VEGF-A, VEGF-C, and basic fibroblast growth factor. Conversely, overexpression of HSP27 in nonangiogenic cells resulted in expansive tumor growth in vivo. By clinical validation, strong HSP27 protein expression was associated with markers of aggressive tumors and decreased survival in patients with breast cancer and melanoma. An HSP27-associated gene expression signature was related to molecular subgroups and survival in breast cancer. Our findings suggest a role for HSP27 in the balance between tumor dormancy and tumor progression, mediated by tumor-vascular interactions. Targeting HSP27 might offer a useful strategy in cancer treatment.


Assuntos
Neoplasias da Mama/metabolismo , Regulação para Baixo , Proteínas de Choque Térmico HSP27/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Animais , Western Blotting , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Feminino , Fator 2 de Crescimento de Fibroblastos/genética , Fator 2 de Crescimento de Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP27/genética , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos SCID , Neovascularização Patológica/genética , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transplante Heterólogo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator C de Crescimento do Endotélio Vascular/genética , Fator C de Crescimento do Endotélio Vascular/metabolismo
3.
mSphere ; 9(2): e0067823, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38323845

RESUMO

The ability of Aedes aegypti mosquitoes to transmit vertebrate pathogens depends on multiple factors, including the mosquitoes' life history traits, immune response, and microbiota (i.e., the microbes associated with the mosquito throughout its life). The microsporidium Edhazardia aedis is an obligate intracellular parasite that specifically infects Ae. aegypti mosquitoes and severely affects mosquito survival and other life history traits critical for pathogen transmission. In this work, we investigated how E. aedis impacts bacterial infection with Serratia marcescens in Ae. aegypti mosquitoes. We measured development, survival, and bacterial load in both larval and adult stages of mosquitoes. In larvae, E. aedis exposure was either horizontal or vertical and S. marcescens was introduced orally. Regardless of the route of transmission, E. aedis exposure resulted in significantly higher S. marcescens loads in larvae. E. aedis exposure also significantly reduced larval survival but subsequent exposure to S. marcescens had no effect. In adult females, E. aedis exposure was only horizontal and S. marcescens was introduced orally or via intrathoracic injection. In both cases, E. aedis infection significantly increased S. marcescens bacterial loads in adult female mosquitoes. In addition, females infected with E. aedis and subsequently injected with S. marcescens suffered 100% mortality which corresponded with a rapid increase in bacterial load. These findings suggest that exposure to E. aedis can influence the establishment and/or replication of other microbes in the mosquito. This has implications for understanding the ecology of mosquito immune defense and potentially disease transmission by mosquito vector species. IMPORTANCE: The microsporidium Edhazardia aedis is a parasite of the yellow fever mosquito, Aedes aegypti. This mosquito transmits multiple viruses to humans in the United States and around the world, including dengue, yellow fever, and Zika viruses. Hundreds of millions of people worldwide will become infected with one of these viruses each year. E. aedis infection significantly reduces the lifespan of Ae. aegypti and is therefore a promising novel biocontrol agent. Here, we show that when the mosquito is infected with this parasite, it is also significantly more susceptible to infection by an opportunistic bacterial pathogen, Serratia marcescens. This novel discovery suggests the mosquito's ability to control infection by other microbes is impacted by the presence of the parasite.


Assuntos
Aedes , Microsporídios , Parasitos , Febre Amarela , Infecção por Zika virus , Zika virus , Animais , Feminino , Humanos , Estados Unidos , Larva/microbiologia
4.
PLoS One ; 19(6): e0304959, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38857239

RESUMO

Amblyomma americanum, a known vector of multiple tick-borne pathogens, has expanded its geographic distribution across the United States in the past decades. Tick microbiomes may play a role shaping their host's life history and vectorial capacity. Bacterial communities associated with A. americanum may reflect, or enable, geographic expansion and studying the microbiota will improve understanding of tick-borne disease ecology. We examined the microbiota structure of 189 adult ticks collected in four regions encompassing their historical and current geographic distribution. Both geographic region of origin and sex were significant predictors of alpha diversity. As in other tick models, within-sample diversity was low and uneven given the presence of dominant endosymbionts. Beta diversity analyses revealed that bacterial profiles of ticks of both sexes collected in the West were significantly different from those of the Historic range. Biomarkers were identified for all regions except the historical range. In addition, Bray-Curtis dissimilarities overall increased with distance between sites. Relative quantification of ecological processes showed that, for females and males, respectively, drift and dispersal limitation were the primary drivers of community assembly. Collectively, our findings highlight how microbiota structural variance discriminates the western-expanded populations of A. americanum ticks from the Historical range. Spatial autocorrelation, and particularly the detection of non-selective ecological processes, are indicative of geographic isolation. We also found that prevalence of Ehrlichia chaffeensis, E. ewingii, and Anaplasma phagocytophilum ranged from 3.40-5.11% and did not significantly differ by region. Rickettsia rickettsii was absent from our samples. Our conclusions demonstrate the value of synergistic analysis of biogeographic and microbial ecology data in investigating range expansion in A. americanum and potentially other tick vectors as well.


Assuntos
Amblyomma , Microbiota , Animais , Feminino , Masculino , Amblyomma/microbiologia , Estados Unidos , Ixodidae/microbiologia
5.
PLoS One ; 19(6): e0305399, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38917214

RESUMO

Mosquitoes (Diptera: Culicidae) are one of the most impactful pests to human society, both as a nuisance and a potential vector of human and animal pathogens. Mosquito larvae develop in still aquatic environments. Eliminating these habitats near high human density or managing them to reduce the suitability for mosquitoes will reduce mosquito populations in these human environments and decrease the overall negative impact of mosquitoes on humans. One common source of standing water in urban and suburban environments is the water that pools in stormwater control measures. Previous studies have shown that some stormwater control measures generate large numbers of mosquitoes while others harbor none, and the reason for this difference remains unclear. Our study focuses on elucidating the factors that cause a stormwater control measure to be more or less suitable for mosquitoes. During the summers of 2021 and 2022, we collected and identified mosquito larvae from thirty stormwater control measures across central Ohio to assess variation in mosquito abundance and diversity among sites. Our goal was to determine if specific types of stormwater control measures (retention ponds, detention ponds, or constructed wetlands) harbored different abundances of mosquitoes or different community structures. We also assessed environmental parameters of these sites to elucidate their effects on mosquito abundance and diversity. Overall, we recorded the highest number of mosquito larvae and species in constructed wetlands. However, these sites were dominated by the innocuous species, Culex territans. Conversely, detention ponds held fewer mosquitoes but a higher proportion of known vector species, including Culex pipiens and Aedes vexans. The total number of mosquitoes across all sites was correlated with higher vegetation, more shade, lower water temperatures, and lower pH, suggesting stormwater control measures with these features may also be hotspots for mosquito proliferation.


Assuntos
Culicidae , Lagoas , Áreas Alagadas , Animais , Culicidae/fisiologia , Ohio , Larva , Biodiversidade , Controle de Mosquitos/métodos , Ecossistema , Humanos , Mosquitos Vetores/fisiologia
6.
Cancer Cell ; 7(3): 251-61, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15766663

RESUMO

Angiogenesis inhibitors, such as TNP-470 and the nontoxic HPMA copolymer-TNP-470 (caplostatin), are emerging as a class of anticancer drugs. We report that TNP-470 and caplostatin inhibit vascular hyperpermeability of tumor blood vessels as well as that induced in mouse skin by different mediators. Treatment with TNP-470 or angiostatin for 3 days was sufficient to reduce permeability of tumor blood vessels, delayed-type hypersensitivity, and pulmonary edema induced by IL-2. TNP-470 also inhibited VPF/VEGF-induced phosphorylation of VEGFR-2, calcium influx, and RhoA activation in endothelial cells. These results identify an activity of TNP-470, that of inhibiting vessel hyperpermeability. This activity likely contributes to TNP-470's antiangiogenic effect and suggests that caplostatin can be used in the treatment of cancer and inflammation.


Assuntos
Inibidores da Angiogênese/química , Inibidores da Angiogênese/farmacologia , Capilares/efeitos dos fármacos , Permeabilidade Capilar/efeitos dos fármacos , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Angiostatinas/farmacologia , Animais , Cálcio/metabolismo , Capilares/metabolismo , Capilares/ultraestrutura , Permeabilidade Capilar/fisiologia , Movimento Celular/efeitos dos fármacos , Cicloexanos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais/ultraestrutura , Feminino , Hipersensibilidade Tardia , Interleucina-2/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neoplasias/irrigação sanguínea , Neoplasias/metabolismo , Neoplasias/patologia , O-(Cloroacetilcarbamoil)fumagilol , Edema Pulmonar/induzido quimicamente , Pele/irrigação sanguínea , Pele/efeitos dos fármacos , Pele/patologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo
7.
Entomol Exp Appl ; 146(3): 321-331, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23420018

RESUMO

Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogenic acid (CA), and other caffeic acid derivatives as they feed on one of their hosts, Nicotiana attenuata L. (Solanaceae), and on artificial diet supplemented with CA. We test the hypothesis that larvae fed on CA-supplemented diet would have better resistance against bacterial infection than larvae fed on a standard CA-free diet by injecting bacteria into the hemocoel of fourth instars. Larvae fed CA-supplemented diet show significantly higher survival of infection with Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper-Bälz, but not of infection with the more virulent Pseudomonas aeruginosa (Schroeter) Migula. Larvae fed on CA-supplemented diet possess a constitutively higher number of circulating hemocytes than larvae fed on the standard diet, but we found no other evidence of increased immune system activity, nor were larvae fed on CA-supplemented diet better able to suppress bacterial proliferation early in the infection. Thus, our data suggest an additional defensive function of CA to the direct toxic inhibition of pathogen proliferation in the gut.

8.
Sci Rep ; 13(1): 12368, 2023 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-37524824

RESUMO

Immune defense is comprised of (1) resistance: the ability to reduce pathogen load, and (2) tolerance: the ability to limit the disease severity induced by a given pathogen load. The study of tolerance in the field of animal immunity is fairly nascent in comparison to resistance. Consequently, studies which examine immune defense comprehensively (i.e. considering both resistance and tolerance in conjunction) are uncommon, despite their exigency in achieving a thorough understanding of immune defense. Furthermore, understanding tolerance in arthropod disease vectors is uniquely relevant, as tolerance is essential to the cyclical transmission of pathogens by arthropods. Here, we tested the effect(s) of dietary sucrose concentration and blood ingestion on resistance and tolerance to Escherichia coli infection in the yellow fever mosquito Aedes aegypti. Resistance and tolerance were measured concurrently and at multiple timepoints. We found that mosquitoes from the restricted sugar treatment displayed enhanced resistance at all timepoints post-infection compared to those from the laboratory standard sugar treatment. Blood also improved resistance, but only early post-infection. While sucrose restriction had no effect on tolerance, we show that consuming blood prior to bacterial infection ameliorates a temporal decline in tolerance that mosquitoes experience when provided with only sugar meals. Taken together, our findings indicate that different dietary components can have unique and sometimes temporally dynamic impacts on resistance and tolerance.


Assuntos
Aedes , Animais , Açúcares/farmacologia , Mosquitos Vetores , Carboidratos/farmacologia , Ingestão de Alimentos
9.
PLoS Negl Trop Dis ; 17(3): e0011218, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36989328

RESUMO

Microbiota studies of Aedes aegypti and other mosquitoes generally focus on the bacterial communities found in adult female midguts. However, other compartments of the digestive tract maintain communities of bacteria which remain almost entirely unstudied. For example, the Dipteran crop is a food storage organ, but few studies have looked at the microbiome of crops in mosquitoes, and only a single previous study has investigated the crop in Ae. aegypti. In this study, we used both culture-dependent and culture-independent methods to compare the bacterial communities in midguts and crops of laboratory reared Ae. aegypti. Both methods revealed a trend towards higher abundance, but also higher variability, of bacteria in the midgut than the crop. When present, bacteria from the genus Elizabethkingia (family Weeksellaceae) dominated midgut bacterial communities. In crops, we found a higher diversity of bacteria, and these communities were generally dominated by acetic acid bacteria (family Acetobacteriaceae) from the genera Tanticharoenia and Asaia. These three taxa drove significant community structure differences between the tissues. We used FAPROTAX to predict the metabolic functions of these communities and found that crop bacterial communities were significantly more likely to contain bacteria capable of methanol oxidation and methylotrophy. Both the presence of acetic acid bacteria (which commonly catabolize sugar to produce acetic acid) and the functional profile that includes methanol oxidation (which is correlated with bacteria found with natural sources like nectar) may relate to the presence of sugar, which is stored in the mosquito crop. A better understanding of what bacteria are present in the digestive tract of mosquitoes and how these communities assemble will inform how the microbiota impacts mosquito physiology and the full spectrum of functions provided by the microbiota. It may also facilitate better methods of engineering the mosquito microbiome for vector control or prevention of disease transmission.


Assuntos
Aedes , Animais , Feminino , Aedes/microbiologia , Metanol , Mosquitos Vetores , Trato Gastrointestinal/microbiologia , Bactérias/genética , Açúcares
10.
Curr Opin Insect Sci ; 50: 100875, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35065286

RESUMO

Arthropods, including mosquitoes, sand flies, tsetse flies, and ticks are vectors of many bacterial, parasitic, and viral pathogens that cause serious disease in humans and animals. Their microbiota, that is, all microorganisms that dwell within their tissues, can impact vector immunity and susceptibility to pathogen infection. Historically, host-pathogen-microbiota interactions have not been well described, with little known about mechanism. In this review, we highlight recent advances in understanding how individual microorganisms and microbial communities interact with vectors and human pathogens, the mechanisms they utilize to achieve these effects, and the potential for exploiting these interactions to control pathogen transmission. These studies fill important knowledge gaps and further our understanding of the roles that the vector microbiota plays in pathogen transmission.


Assuntos
Artrópodes , Microbiota , Animais , Vetores Artrópodes , Artrópodes/microbiologia , Mosquitos Vetores , Vertebrados
11.
Front Microbiol ; 12: 645362, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34220739

RESUMO

The midgut microbiota of the yellow fever mosquito Aedes aegypti impacts pathogen susceptibility and transmission by this important vector species. However, factors influencing the composition and size of the microbiome in mosquitoes are poorly understood. We investigated the impact of larval diet abundance during development on the composition and size of the larval and adult microbiota by rearing Aedes aegypti under four larval food regimens, ranging from nutrient deprivation to nutrient excess. We assessed the persistent impacts of larval diet availability on the microbiota of the larval breeding water, larval mosquitoes, and adult mosquitoes under sugar and blood fed conditions using qPCR and high-throughput 16S amplicon sequencing to determine bacterial load and microbiota composition. Bacterial loads in breeding water increased with increasing larval diet. Larvae reared with the lowest diet abundance had significantly fewer bacteria than larvae from two higher diet treatments, but not from the highest diet abundance. Adults from the lowest diet abundance treatment had significantly fewer bacteria in their midguts compared to all higher diet abundance treatments. Larval diet amount also had a significant impact on microbiota composition, primarily within larval breeding water and larvae. Increasing diet correlated with increased relative levels of Enterobacteriaceae and Flavobacteriaceae and decreased relative levels of Sphingomonadaceae. Multiple individual OTUs were significantly impacted by diet including one mapping to the genus Cedecea, which increased with higher diet amounts. This was consistent across all sample types, including sugar fed and blood fed adults. Taken together, these data suggest that availability of diet during development can cause lasting shifts in the size and composition of the microbiota in the disease vector Aedes aegypti.

12.
Microbiome ; 9(1): 36, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33522965

RESUMO

In the past decade, there has been increasing interest in mosquito microbiome research, leading to large amounts of data on different mosquito species, with various underlying physiological characteristics, and from diverse geographical locations. However, guidelines and standardized methods for conducting mosquito microbiome research are lacking. To streamline methods in mosquito microbiome research and optimize data quality, reproducibility, and comparability, as well as facilitate data curation in a centralized location, we are establishing the Mosquito Microbiome Consortium, a collaborative initiative for the advancement of mosquito microbiome research. Our overall goal is to collectively work on unraveling the role of the mosquito microbiome in mosquito biology, while critically evaluating its potential for mosquito-borne disease control. This perspective serves to introduce the consortium and invite broader participation. It highlights the issues we view as most pressing to the community and proposes guidelines for conducting mosquito microbiome research. We focus on four broad areas in this piece: (1) sampling/experimental design for field, semi-field, or laboratory studies; (2) metadata collection; (3) sample processing, sequencing, and use of appropriate controls; and (4) data handling and analysis. We finally summarize current challenges and highlight future directions in mosquito microbiome research. We hope that this piece will spark discussions around this area of disease vector biology, as well as encourage careful considerations in the design and implementation of mosquito microbiome research. Video Abstract.


Assuntos
Culicidae/microbiologia , Metagenômica , Microbiota , Pesquisa/organização & administração , Pesquisa/tendências , Animais , Reprodutibilidade dos Testes
13.
Proc Biol Sci ; 277(1700): 3649-57, 2010 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-20573620

RESUMO

Post-mating reduction in immune defence is common in female insects, and a trade-off between mating and immunity could affect the evolution of immunity. In this work, we tested the capacity of virgin and mated female Drosophila melanogaster to defend against infection by four bacterial pathogens. We found that female D. melanogaster suffer post-mating immunosuppression in a pathogen-dependent manner. The effect of mating was seen after infection with two bacterial pathogens (Providencia rettgeri and Providencia alcalifaciens), though not after infection with two other bacteria (Enterococcus faecalis and Pseudomonas aeruginosa). We then asked whether the evolution of post-mating immunosuppression is primarily a 'female' or 'male' trait by assaying for genetic variation among females for the degree of post-mating immune suppression they experience and among males for the level of post-mating immunosuppression they elicit in their mates. We also assayed for an interaction between male and female genotypes to test the specific hypothesis that the evolution of a trade-off between mating and immune defence in females might be being driven by sexual conflict. We found that females, but not males, harbour significant genetic variation for post-mating immunosuppression, and we did not detect an interaction between female and male genotypes. We thus conclude that post-mating immune depression is predominantly a 'female' trait, and find no evidence that it is evolving under sexual conflict.


Assuntos
Drosophila melanogaster/imunologia , Drosophila melanogaster/microbiologia , Variação Genética , Terapia de Imunossupressão , Caracteres Sexuais , Comportamento Sexual Animal/fisiologia , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Enterococcus faecalis/patogenicidade , Feminino , Imunidade Inata/genética , Masculino , Providencia/patogenicidade , Pseudomonas aeruginosa/patogenicidade , Reprodução/fisiologia
14.
J Cell Biol ; 168(4): 643-53, 2005 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-15716381

RESUMO

The anti-angiogenic effect of thrombospondin-1 has been shown to be mediated through binding of the type-1 repeat (TSR) domain to the CD36 transmembrane receptor. We now report that the TSR domain can inhibit VEGF-induced migration in human umbilical vein endothelial cells (HUVEC), cells that lack CD36. Moreover, we identified beta1 integrins as a critical receptor in TSR-mediated inhibition of migration in HUVEC. Using pharmacological inhibitors of downstream VEGF receptor effectors, we found that phosphoinositide 3-kinase (PI3k) was essential for TSR-mediated inhibition of HUVEC migration, but that neither PLCgamma nor Akt was necessary for this response. Furthermore, beta1 integrins were critical for TSR-mediated inhibition of microvascular endothelial cells, cells that express CD36. Together, our results indicate that beta1 integrins mediate the anti-migratory effects of TSR through a PI3k-dependent mechanism.


Assuntos
Movimento Celular/fisiologia , Células Endoteliais/fisiologia , Integrina beta1/metabolismo , Transdução de Sinais/fisiologia , Trombospondina 1/metabolismo , Antígenos CD36/metabolismo , Células Cultivadas , Células Endoteliais/metabolismo , Humanos , Fosfatidilinositol 3-Quinases/metabolismo , Fosfolipase C gama , Proteínas Serina-Treonina Quinases/metabolismo , Estrutura Terciária de Proteína/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , RNA Interferente Pequeno/metabolismo , Fosfolipases Tipo C/metabolismo , Veias Umbilicais/citologia , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
J Vis Exp ; (162)2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32865535

RESUMO

Edhazardia aedis is a microsporidian parasite of Aedes aegypti mosquitoes, a disease vector that transmits multiple arboviruses which cause millions of disease cases each year. E. aedis causes mortality and reduced reproductive fitness in the mosquito vector and has been explored for its potential as a biocontrol agent. The protocol we present for culturing E. aedis is based on its natural infection cycle, which involves both horizontal and vertical transmission at different life stages of the mosquito host. Ae. aegypti mosquitoes are exposed to spores in the larval stage. These infected larvae then mature into adults and transmit the parasite vertically to their offspring. Infected offspring are then used as a source of spores for future horizontal transmission. Culturing E. aedis can be challenging to the uninitiated given the complexities of the parasite's life cycle, and this protocol provides detailed guidance and visual aids for clarification.


Assuntos
Aedes/parasitologia , Microsporídios , Parasitologia/métodos , Animais , Transmissão de Doença Infecciosa , Transmissão Vertical de Doenças Infecciosas , Larva/parasitologia , Mosquitos Vetores
16.
Dev Comp Immunol ; 104: 103540, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31726064

RESUMO

Here we have investigated whether bacterial challenges to larval stages of Aedes aegypti can influence the adults' immune and vector competence for dengue and Zika viruses. We show that larval exposure to live Bacillus thuringiensis Berliner and Enterobacter ludwigii can result in the modulation of virus infection at the adult stage in the absence of bacterial carry-over between the two developmental stages. We observed a significant reduction in virus infection intensity in the mosquitoes exposed to bacteria as larvae but not re-exposed as adults. The pattern of immune gene transcript regulation after bacterial exposure varied between adults, depending on whether or not they had been exposed to bacteria as larvae. Adults exposed to bacteria as larvae showed an earlier immune gene mRNA enrichment when re-exposed as adults than did adults not exposed as larvae. Bacterial exposure of larvae appears to have only modest effects on adult fitness.


Assuntos
Aedes/imunologia , Infecções por Arbovirus/imunologia , Arbovírus/fisiologia , Bacillus thuringiensis/fisiologia , Enterobacter/fisiologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Bactérias Gram-Positivas/imunologia , Animais , Vetores de Doenças , Exposição Ambiental/efeitos adversos , Regulação da Expressão Gênica , Imunidade Inata/genética , Larva , Estágios do Ciclo de Vida , Mosquitos Vetores
17.
Pathogens ; 9(5)2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32429180

RESUMO

Mosquitoes can transmit many infectious diseases, such as malaria, dengue, Zika, yellow fever, and lymphatic filariasis. Current mosquito control strategies are failing to reduce the severity of outbreaks that still cause high human morbidity and mortality worldwide. Great expectations have been placed on genetic control methods. Among other methods, genetic modification of the bacteria colonizing different mosquito species and expressing anti-pathogen molecules may represent an innovative tool to combat mosquito-borne diseases. Nevertheless, this emerging approach, known as paratransgenesis, requires a detailed understanding of the mosquito microbiota and an accurate characterization of selected bacteria candidates. The acetic acid bacteria Asaia is a promising candidate for paratransgenic approaches. We have previously reported that Asaia symbionts play a beneficial role in the normal development of Anopheles mosquito larvae, but no study has yet investigated the role(s) of Asaia in adult mosquito biology. Here we report evidence on how treatment with a highly specific anti-Asaia monoclonal antibody impacts the survival and physiology of adult Anopheles stephensi mosquitoes. Our findings offer useful insight on the role of Asaia in several physiological systems of adult mosquitoes, where the influence differs between males and females.

18.
Cancer Res ; 67(20): 9980-5, 2007 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-17942931

RESUMO

Bacillus anthracis protective antigen (PA), the B subunit of the binary anthrax toxin, binds to the cellular receptors capillary morphogenesis gene 2 protein and tumor endothelial marker 8 with high affinity. Both receptors are expressed on endothelial cells during angiogenesis. We sought to determine whether one could inhibit angiogenesis by interfering with the binding of these receptors to their endogenous ligands. Here, we show that wild-type PA inhibits both vascular endothelial growth factor-induced and basic fibroblast growth factor-induced angiogenesis at moderate but statistically significant levels. Structure-activity studies identified a PA mutant that exhibited markedly enhanced inhibition of angiogenesis and also inhibited tumor growth in vivo. This mutant, PASSSR, is unable to undergo normal cellular processing and, thus, remains bound to the surface receptor. Further mutation of PASSSR so that it does not bind to these cell surface receptors abolished its ability to inhibit angiogenesis. We conclude that high-affinity anthrax toxin receptor (ATR) ligands, such as PA and PASSSR, are angiogenesis inhibitors and that ATRs are useful targets for antiangiogenic therapy. These results also suggest that endothelial cell-binding proteins from additional pathogens may inhibit angiogenesis and raise the question of the role of such inhibition in pathogenesis.


Assuntos
Inibidores da Angiogênese/farmacologia , Antígenos de Bactérias/farmacologia , Toxinas Bacterianas/farmacologia , Carcinoma Pulmonar de Lewis/irrigação sanguínea , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Animais , Antígenos de Bactérias/genética , Antígenos de Bactérias/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Processos de Crescimento Celular/efeitos dos fármacos , Córnea/irrigação sanguínea , Neovascularização da Córnea/induzido quimicamente , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Fator 2 de Crescimento de Fibroblastos/antagonistas & inibidores , Humanos , Proteínas de Membrana/biossíntese , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos , Mutação , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/metabolismo , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/patologia , Neovascularização Fisiológica/efeitos dos fármacos , Receptores de Superfície Celular/biossíntese , Receptores de Superfície Celular/metabolismo , Receptores de Peptídeos , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores
19.
Trends Parasitol ; 40(6): 529-530, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38677926
20.
Insects ; 10(3)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875967

RESUMO

In addition to transferring sperm, male mosquitoes deliver several proteins, hormones and other factors to females in their seminal fluid that inhibit remating, alter host-seeking behaviors and stimulate oviposition. Recently, bioinformatics, transcriptomics and proteomics have been used to characterize the genes transcribed in male reproductive tissues and the individual proteins that are delivered to females. Thanks to these foundational studies, we now understand the complexity of the ejaculate in several mosquito species. Building on this work, researchers have begun to identify the functions of various proteins and hormones in the male ejaculate, and how they mediate their effects on female mosquitoes. Here, we present an overview of these studies, followed by a discussion of an under-studied aspect of male reproductive physiology: the effects of biotic and abiotic factors on the composition of the ejaculate. We argue that future research in this area would improve our understanding of male reproductive biology from a physiological and ecological perspective, and that researchers may be able to leverage this information to study key components of the ejaculate. Furthermore, this work has the potential to improve mosquito control by allowing us to account for relevant factors when implementing vector control strategies involving male reproductive biology.

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