RESUMEN
Monocytes play an important role in the host defense against Plasmodium vivax as the main source of inflammatory cytokines and mitochondrial reactive oxygen species (mROS). Here, we show that monocyte metabolism is altered during human P. vivax malaria, with mitochondria playing a major function in this switch. The process involves a reprograming in which the cells increase glucose uptake and produce ATP via glycolysis instead of oxidative phosphorylation. P. vivax infection results in dysregulated mitochondrial gene expression and in altered membrane potential leading to mROS increase rather than ATP production. When monocytes were incubated with P. vivax-infected reticulocytes, mitochondria colocalized with phagolysosomes containing parasites representing an important source mROS. Importantly, the mitochondrial enzyme superoxide dismutase 2 (SOD2) is simultaneously induced in monocytes from malaria patients. Taken together, the monocyte metabolic reprograming with an increased mROS production may contribute to protective responses against P. vivax while triggering immunomodulatory mechanisms to circumvent tissue damage. IMPORTANCE Plasmodium vivax is the most widely distributed causative agent of human malaria. To achieve parasite control, the human immune system develops a substantial inflammatory response that is also responsible for the symptoms of the disease. Among the cells involved in this response, monocytes play an important role. Here, we show that monocyte metabolism is altered during malaria, with its mitochondria playing a major function in this switch. This change involves a reprograming process in which the cells increase glucose uptake and produce ATP via glycolysis instead of oxidative phosphorylation. The resulting altered mitochondrial membrane potential leads to an increase in mitochondrial reactive oxygen species rather than ATP. These data suggest that agents that change metabolism should be investigated and used with caution during malaria.
Asunto(s)
Mitocondrias/metabolismo , Mitocondrias/patología , Monocitos/metabolismo , Monocitos/patología , Plasmodium vivax/inmunología , Reticulocitos/parasitología , Adenosina Trifosfato/metabolismo , Adolescente , Adulto , Anciano , Femenino , Expresión Génica , Glucólisis , Humanos , Malaria Vivax/inmunología , Malaria Vivax/fisiopatología , Masculino , Persona de Mediana Edad , Mitocondrias/genética , Monocitos/citología , Monocitos/inmunología , Fagosomas/inmunología , Fagosomas/parasitología , Plasmodium vivax/genética , Plasmodium vivax/patogenicidad , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Adulto JovenRESUMEN
Zika virus (ZIKV) caused a public health threat in the United States in 2016, leading to rapid development and implementation of blood screening assays for ZIKV RNA. Several ZIKV sequences from clinical cases have been reported, but none from asymptomatic/pre-symptomatic infections. We isolated and sequenced ZIKV from asymptomatic/pre-symptomatic blood donor (ABD-ZIKV) samples and compared with reported clinical sequences. Twelve ABD-ZIKV isolates were produced from 67 cultivated samples, and isolates were genetically similar among themselves. Most isolates shared mutations with the clinical isolate PRVABC59 2015, whereas two ABD-ZIKV isolates shared specific mutations with U.S. clinical isolates from 2016. The ABD-ZIKV strains clustered into two distinct subclades: one comprised mostly ABD-ZIKV from Puerto Rico, and another one comprised ABD-ZIKV from Florida and QTX-02 isolate (Puerto Rico). In this study, we showed the circulation of two slightly distinct virus strains among Puerto Rico blood donors, one of which was also reported in Florida.
Asunto(s)
Donantes de Sangre , Filogenia , Infección por el Virus Zika/sangre , Virus Zika/genética , Virus Zika/aislamiento & purificación , Adulto , Enfermedades Transmisibles Emergentes/sangre , Enfermedades Transmisibles Emergentes/epidemiología , Florida/epidemiología , Genómica , Humanos , Puerto Rico/epidemiología , Infección por el Virus Zika/diagnóstico , Infección por el Virus Zika/epidemiologíaRESUMEN
BACKGROUND: The activation of innate immune responses by Plasmodium vivax results in activation of effector cells and an excessive production of pro-inflammatory cytokines that may culminate in deleterious effects. Here, we examined the activation and function of neutrophils during acute episodes of malaria. MATERIALS AND METHODS: Blood samples were collected from P. vivax-infected patients at admission (day 0) and 30-45 days after treatment with chloroquine and primaquine. Expression of activation markers and cytokine levels produced by highly purified monocytes and neutrophils were measured by the Cytometric Bead Assay. Phagocytic activity, superoxide production, chemotaxis and the presence of G protein-coupled receptor (GRK2) were also evaluated in neutrophils from malaria patients. PRINCIPAL FINDINGS: Both monocytes and neutrophils from P. vivax-infected patients were highly activated. While monocytes were found to be the main source of cytokines in response to TLR ligands, neutrophils showed enhanced phagocytic activity and superoxide production. Interestingly, neutrophils from the malaria patients expressed high levels of GRK2, low levels of CXCR2, and displayed impaired chemotaxis towards IL-8 (CXCL8). CONCLUSION: Activated neutrophils from malaria patients are a poor source of pro-inflammatory cytokines and display reduced chemotactic activity, suggesting a possible mechanism for an enhanced susceptibility to secondary bacterial infection during malaria.
Asunto(s)
Citocinas/biosíntesis , Malaria Vivax/inmunología , Malaria Vivax/patología , Neutrófilos/inmunología , Neutrófilos/parasitología , Plasmodium vivax/inmunología , Plasmodium vivax/patogenicidad , Adolescente , Adulto , Anciano , Quimiotaxis , Femenino , Citometría de Flujo , Quinasa 2 del Receptor Acoplado a Proteína-G/biosíntesis , Humanos , Malaria Vivax/complicaciones , Masculino , Persona de Mediana Edad , Monocitos/inmunología , Monocitos/parasitología , Fagocitosis , Superóxidos/metabolismo , Adulto JovenRESUMEN
BACKGROUND: Despite governmental and private efforts on providing malaria control, this disease continues to be a major health threat. Thus, innovative strategies are needed to reduce disease burden. The malaria vectors, through the injection of saliva into the host skin, play important role on disease transmission and may influence malaria morbidity. This study describes the humoral immune response against Anopheles (An.) darlingi saliva in volunteers from the Brazilian Amazon and addresses the association between levels of specific antibodies and clinical presentation of Plasmodium (P.) vivax infection. METHODS: Adult volunteers from communities in the Rondônia State, Brazil, were screened in order to assess the presence of P. vivax infection by light microscopy and nested PCR. Non-infected volunteers and individuals with symptomatic or symptomless infection were randomly selected and plasma collected. An. darlingi salivary gland sonicates (SGS) were prepared and used to measure anti-saliva antibody levels. Plasma interleukin (IL)-10 and interferon (IFN)-gamma levels were also estimated and correlated to anti-SGS levels. RESULTS: Individuals infected with P. vivax presented higher levels of anti-SGS than non-infected individuals and antibody levels could discriminate infection. Furthermore, anti-saliva antibody measurement was also useful to distinguish asymptomatic infection from non-infection, with a high likelihood ratio. Interestingly, individuals with asymptomatic parasitaemia presented higher titers of anti-SGS and lower IFN-gamma/IL-10 ratio than symptomatic ones. In P. vivax-infected asymptomatic individuals, the IFN-gamma/IL-10 ratio was inversely correlated to anti-SGS titers, although not for while in symptomatic volunteers. CONCLUSION: The estimation of anti-An. darlingi antibody levels can indicate the probable P. vivax infection status and also could serve as a marker of disease severity in this region of Brazilian Amazon.
Asunto(s)
Anopheles/inmunología , Anticuerpos/sangre , Proteínas de Insectos/inmunología , Malaria Vivax/diagnóstico , Saliva/inmunología , Adulto , Animales , Biomarcadores/sangre , Brasil , Femenino , Humanos , Interferón gamma/sangre , Interleucina-10/sangre , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Adulto JovenRESUMEN
During the last 20 years, there have been an increasing number of reports on endogenous phospholipase A(2) inhibitors (PLIs) in the sera of snakes. These studies have demonstrated the existence of three different structural classes of PLIs (alpha, beta and gamma). The gamma class members are potent inhibitors of phospholipases A(2) (PLA(2)) from the venom of Viperidae snakes. These enzymes, together with the mammalian pro-inflammatory PLA(2), belong to the IIA class of the PLA(2)-superfamily. Although coming from distinct sources, these phospholipases A(2) share main structural features. For this reason, gammaPLIs have been considered as potential models for the development of selective inhibitors of pro-inflammatory PLA(2) in humans. In spite of the rich diversity of the ophidian fauna in Brazil, only two gammaPLI representatives, from Crotalus durissus terrificus and Lachesis muta, have been described in Brazilian snakes so far. Here we investigated the presence of transcripts of novel gammaPLIs in six Bothrops species (Viperidae, Crotalinae) commonly found in our country: Bothrops alternatus, Bothrops erythromelas, Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni and Bothrops neuwiedi. gammaPLI transcripts were present in every species analysed. The deduced mature proteins possessed 181 amino acid residues following a 19-residue signal peptide, similar to the gammaPLIs from C. d. terrificus taken as our model, with the exception of the deduced proteins from B. erythromelas and B. neuwiedi snakes. In these particular cases, an insertion of 4-amino acid residues was consistently present. A Bayesian tree was obtained for the Brazilian Bothrops gammaPLIs, showing four clusters: (1) L. muta and B. jararacussu, (2) B. alternatus, (3) B. erythromelas and B. neuwiedi, (4) B. jararaca and B. moojeni. Detailed structural analysis and further comparisons of these novel Bothrops inhibitors with gammaPLIs from New and Old World snakes are provided.
Asunto(s)
Bothrops/metabolismo , Inhibidores Enzimáticos/aislamiento & purificación , Fosfolipasas A2 Grupo IV/antagonistas & inhibidores , Secuencia de Aminoácidos , Animales , Inhibidores Enzimáticos/química , Datos de Secuencia Molecular , Fosforilación , FilogeniaRESUMEN
The technique to generate transgenic mosquitoes requires adaptation for each target species because of aspects related to species biology, sensitivity to manipulation and rearing conditions. Here we tested different parameters on the microinjection procedure in order to obtain a transgenic Neotropical mosquito species. By using a transposon-based strategy we were able to successfully transform Aedes fluviatilis (Lutz), which can be used as an avian malaria model. These results demonstrate the usefulness of the piggyBac transposable element as a transformation vector for Neotropical mosquito species and opens up new research frontiers for South American mosquito vectors.
Asunto(s)
Aedes/genética , Elementos Transponibles de ADN/genética , Técnicas de Transferencia de Gen , Insectos Vectores/genética , Transformación Genética/genética , Animales , Femenino , Genes de Insecto , Células Germinativas , Masculino , MicroinyeccionesRESUMEN
The technique to generate transgenic mosquitoes requires adaptation for each target species because of aspects related to species biology, sensitivity to manipulation and rearing conditions. Here we tested different parameters on the microinjection procedure in order to obtain a transgenic Neotropical mosquito species. By using a transposon-based strategy we were able to successfully transform Aedes fluviatilis (Lutz), which can be used as an avian malaria model. These results demonstrate the usefulness of the piggyBac transposable element as a transformation vector for Neotropical mosquito species and opens up new research frontiers for South American mosquito vectors.