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1.
EBioMedicine ; 94: 104723, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37487418

RESUMEN

BACKGROUND: Dengue virus outbreaks are increasing in number and severity worldwide. Viral transmission is assumed to require a minimum time period of viral replication within the mosquito midgut. It is unknown if alternative transmission periods not requiring replication are possible. METHODS: We used a mouse model of dengue virus transmission to investigate the potential of mechanical transmission of dengue virus. We investigated minimal viral titres necessary for development of symptoms in bitten mice and used resulting parameters to inform a new model of dengue virus transmission within a susceptible population. FINDINGS: Naïve mice bitten by mosquitoes immediately after they took partial blood meals from dengue infected mice showed symptoms of dengue virus, followed by mortality. Incorporation of mechanical transmission into mathematical models of dengue virus transmission suggest that this supplemental transmission route could result in larger outbreaks which peak sooner. INTERPRETATION: The potential of dengue transmission routes independent of midgut viral replication has implications for vector control strategies that target mosquito lifespan and suggest the possibility of similar mechanical transmission routes in other disease-carrying mosquitoes. FUNDING: This study was funded by grants from the National Health Research Institutes, Taiwan (04D2-MMMOST02), the Human Frontier Science Program (RGP0033/2021), the National Institutes of Health (1R01AI143698-01A1, R01AI151004 and DP2AI152071) and the Ministry of Science and Technology, Taiwan (MOST104-2321-B-400-016).


Asunto(s)
Aedes , Virus del Dengue , Dengue , Humanos , Animales , Ratones , Dengue/epidemiología , Brotes de Enfermedades , Mosquitos Vectores
2.
J Biomed Sci ; 30(1): 12, 2023 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-36803804

RESUMEN

BACKGROUND: Zika virus (ZIKV) infection is clinically known to induce testicular swelling, termed orchitis, and potentially impact male sterility, but the underlying mechanisms remain unclear. Previous reports suggested that C-type lectins play important roles in mediating virus-induced inflammatory reactions and pathogenesis. We thus investigated whether C-type lectins modulate ZIKV-induced testicular damage. METHODS: C-type lectin domain family 5 member A (CLEC5A) knockout mice were generated in a STAT1-deficient immunocompromised background (denoted clec5a-/-stat1-/-) to enable testing of the role played by CLEC5A after ZIKV infection in a mosquito-to-mouse disease model. Following ZIKV infection, mice were subjected to an array of analyses to evaluate testicular damage, including ZIKV infectivity and neutrophil infiltration estimation via quantitative RT-PCR or histology and immunohistochemistry, inflammatory cytokine and testosterone detection, and spermatozoon counting. Furthermore, DNAX-activating proteins for 12 kDa (DAP12) knockout mice (dap12-/-stat1-/-) were generated and used to evaluate ZIKV infectivity, inflammation, and spermatozoa function in order to investigate the potential mechanisms engaged by CLEC5A. RESULTS: Compared to experiments conducted in ZIKV-infected stat1-/- mice, infected clec5a-/-stat1-/- mice showed reductions in testicular ZIKV titer, local inflammation and apoptosis in testis and epididymis, neutrophil invasion, and sperm count and motility. CLEC5A, a myeloid pattern recognition receptor, therefore appears involved in the pathogenesis of ZIKV-induced orchitis and oligospermia. Furthermore, DAP12 expression was found to be decreased in the testis and epididymis tissues of clec5a-/-stat1-/- mice. As for CLEC5A deficient mice, ZIKV-infected DAP12-deficient mice also showed reductions in testicular ZIKV titer and local inflammation, as well as improved spermatozoa function, as compared to controls. CLEC5A-associated DAP12 signaling appears to in part regulate ZIKV-induced testicular damage. CONCLUSIONS: Our analyses reveal a critical role for CLEC5A in ZIKV-induced proinflammatory responses, as CLEC5A enables leukocytes to infiltrate past the blood-testis barrier and induce testicular and epididymal tissue damage. CLEC5A is thus a potential therapeutic target for the prevention of injuries to male reproductive organs in ZIKV patients.


Asunto(s)
Orquitis , Infección por el Virus Zika , Virus Zika , Humanos , Masculino , Ratones , Animales , Semen/metabolismo , Ratones Noqueados , Inflamación/genética , Lectinas Tipo C/genética , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo
3.
Front Immunol ; 12: 640367, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33767710

RESUMEN

The C-type lectins, one family of lectins featuring carbohydrate binding domains which participate in a variety of bioprocesses in both humans and mosquitoes, including immune response, are known to target DENV. A human C-type lectin protein CLEC18A in particular shows extensive glycan binding abilities and correlates with type-I interferon expression, making CLEC18A a potential player in innate immune responses to DENV infection; this potential may provide additional regulatory point in improving mosquito immunity. Here, we established for the first time a transgenic Aedes aegypti line that expresses human CLEC18A. This expression enhanced the Toll immune pathway responses to DENV infection. Furthermore, viral genome and virus titers were reduced by 70% in the midgut of transgenic mosquitoes. We found significant changes in the composition of the midgut microbiome in CLEC18A expressing mosquitoes, which may result from the Toll pathway enhancement and contribute to DENV inhibition. Transgenic mosquito lines offer a compelling option for studying DENV pathogenesis, and our analyses indicate that modifying the mosquito immune system via expression of a human immune gene can significantly reduce DENV infection.


Asunto(s)
Aedes/inmunología , Aedes/virología , Animales Modificados Genéticamente , Dengue/inmunología , Lectinas Tipo C/inmunología , Aedes/genética , Animales , Animales Modificados Genéticamente/genética , Animales Modificados Genéticamente/inmunología , Virus del Dengue , Modelos Animales de Enfermedad , Humanos , Mosquitos Vectores/genética , Mosquitos Vectores/inmunología , Mosquitos Vectores/virología
4.
Viruses ; 12(10)2020 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-33003584

RESUMEN

Dengue virus (DENV), the pathogen that causes dengue fever, is mainly transmitted by Aedes aegypti. Surveillance of infected mosquitoes is a major component of integrated mosquito control methods for reducing the risk of vector-born disease outbreaks. However, a specialized rapid test for DENV detection in mosquitoes is not currently available. Utilizing immunoblotting, we found that the secretion of NS1 from both a DENV-infected mosquito cell line and mosquito bodies was below the detection threshold. However, when Triton X-100 was used to lyse infected mosquitoes, intracellular NS1 was released, and could then be effectively detected by the NS1 rapid test. The distribution of DENV NS1 in intrathoracically infected mosquitoes was different from that of orally infected mosquitoes. Next, we performed sensitivity tests by bisecting mosquitoes longitudinally; one half of each mosquito was subjected to the NS1 rapid test while the other half was used for qPCR confirmation. This modified test had a sensitivity of nearly 90% from five days post-infection onwards, while DENV had escaped from the midgut barrier. This adapted test offers a valuable, easy-to-use tool for mosquito surveillance, which is a crucial component of DENV disease control.


Asunto(s)
Virus del Dengue/genética , Virus del Dengue/aislamiento & purificación , Dengue/diagnóstico , Mosquitos Vectores/virología , Proteínas no Estructurales Virales/genética , Aedes/virología , Animales , Línea Celular , Chlorocebus aethiops , Dengue/virología , Células Vero
5.
Dis Model Mech ; 13(8)2020 08 27.
Artículo en Inglés | MEDLINE | ID: mdl-32680850

RESUMEN

Maple syrup urine disease (MSUD) is an inherited error in the metabolism of branched-chain amino acids (BCAAs) caused by a severe deficiency of the branched-chain α-ketoacid dehydrogenase (BCKDH) complex, which ultimately leads to neurological disorders. The limited therapies, including protein-restricted diets and liver transplants, are not as effective as they could be for the treatment of MSUD due to the current lack of molecular insights into the disease pathogenesis. To address this issue, we developed a Drosophila model of MSUD by knocking out the dDBT gene, an ortholog of the human gene encoding the dihydrolipoamide branched chain transacylase (DBT) subunit of BCKDH. The homozygous dDBT mutant larvae recapitulate an array of MSUD phenotypes, including aberrant BCAA accumulation, developmental defects, poor mobile behavior and disrupted L-glutamate homeostasis. Moreover, the dDBT mutation causes neuronal apoptosis during the developmental progression of larval brains. The genetic and functional evidence generated by in vivo depletion of dDBT expression in the eye indicates severe impairment of retinal rhabdomeres. Further, the dDBT mutant shows elevated oxidative stress and higher lipid peroxidation accumulation in the larval brain. Therefore, we conclude from in vivo evidence that the loss of dDBT results in oxidative brain damage that may lead to neuronal cell death and contribute to aspects of MSUD pathology. Importantly, when the dDBT mutants were administrated with Metformin, the aberrances in BCAA levels and motor behavior were ameliorated. This intriguing outcome strongly merits the use of the dDBT mutant as a platform for developing MSUD therapies.This article has an associated First Person interview with the joint first authors of the paper.


Asunto(s)
Aminoácidos de Cadena Ramificada/metabolismo , Apoptosis , Encéfalo/enzimología , Caseína Cinasa 1 épsilon/deficiencia , Proteínas de Drosophila/deficiencia , Drosophila melanogaster/enzimología , Enfermedad de la Orina de Jarabe de Arce/enzimología , Neurogénesis , Neuronas/enzimología , Animales , Animales Modificados Genéticamente , Encéfalo/efectos de los fármacos , Encéfalo/embriología , Caseína Cinasa 1 épsilon/genética , Modelos Animales de Enfermedad , Proteínas de Drosophila/genética , Drosophila melanogaster/efectos de los fármacos , Drosophila melanogaster/embriología , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica , Predisposición Genética a la Enfermedad , Larva/enzimología , Larva/genética , Peroxidación de Lípido , Masculino , Enfermedad de la Orina de Jarabe de Arce/tratamiento farmacológico , Enfermedad de la Orina de Jarabe de Arce/genética , Enfermedad de la Orina de Jarabe de Arce/patología , Metformina/farmacología , Actividad Motora , Neuronas/efectos de los fármacos , Neuronas/patología , Estrés Oxidativo , Fenotipo
6.
Nat Commun ; 8(1): 24, 2017 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-28634323

RESUMEN

Neuroinflammation caused by local deposits of Aß42 in the brain is key for the pathogenesis and progression of Alzheimer's disease. However, inflammation in the brain is not always a response to local primary insults. Gut microbiota dysbiosis, which is recently emerging as a risk factor for psychiatric disorders, can also initiate a brain inflammatory response. It still remains unclear however, whether enteric dysbiosis also contributes to Alzheimer's disease. Here we show that in a Drosophila Alzheimer's disease model, enterobacteria infection exacerbated progression of Alzheimer's disease by promoting immune hemocyte recruitment to the brain, thereby provoking TNF-JNK mediated neurodegeneration. Genetic depletion of hemocytes attenuates neuroinflammation and alleviated neurodegeneration. We further found that enteric infection increases the motility of the hemocytes, making them more readily attracted to the brain with an elevated oxidative stress status. This work highlights the importance of gut-brain crosstalk as a fundamental regulatory system in modulating Alzheimer's disease neurodegeneration.Emerging evidence suggests that gut microbiota influences immune function in the brain and may play a role in neurological diseases. Here, the authors offer in vivo evidence from a Drosophila model that supports a role for gut microbiota in modulating the progression of Alzheimer's disease.


Asunto(s)
Enfermedad de Alzheimer/microbiología , Encéfalo/microbiología , Drosophila melanogaster/microbiología , Disbiosis/microbiología , Infecciones por Enterobacteriaceae/microbiología , Tracto Gastrointestinal/microbiología , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/inmunología , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/genética , Péptidos beta-Amiloides/inmunología , Animales , Péptidos Catiónicos Antimicrobianos/genética , Péptidos Catiónicos Antimicrobianos/inmunología , Encéfalo/inmunología , Encéfalo/patología , Movimiento Celular/inmunología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Proteínas de Drosophila/genética , Proteínas de Drosophila/inmunología , Drosophila melanogaster/inmunología , Disbiosis/complicaciones , Disbiosis/inmunología , Disbiosis/patología , Enterobacteriaceae/crecimiento & desarrollo , Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/complicaciones , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/patología , Tracto Gastrointestinal/inmunología , Regulación de la Expresión Génica , Hemocitos/inmunología , Hemocitos/microbiología , Hemocitos/patología , Humanos , Procedimientos de Reducción del Leucocitos , MAP Quinasa Quinasa 4/genética , MAP Quinasa Quinasa 4/inmunología , Microbiota/inmunología , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Transducción de Señal , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología
7.
Cell Host Microbe ; 11(4): 410-7, 2012 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-22520468

RESUMEN

Local infections can trigger immune responses in distant organs, and this interorgan immunological crosstalk helps maintain immune homeostasis. We find that enterobacterial infection or chemically and genetically stimulating reactive oxygen species (ROS)-induced stress responses in the Drosophila gut triggers global antimicrobial peptide (AMP) responses in the fat body, a major immune organ in flies. ROS stress induces nitric oxide (NO) production in the gut, which triggers production of the AMP Diptericin, but not Drosomycin, in the fat body. Hemocytes serve as a signaling relay for communication between intestinal ROS/NO signaling and fat body AMP responses. The induction of AMP responses requires Rel/NF-κB activation within the fat body. Although Rel-mediated Drosomycin induction is repressed by the AP-1 transcription factor, this repressor activity is inhibited by intestinal ROS. Thus, intestinal ROS signaling plays an important role in initiating gut-to-fat body immunological communication in Drosophila.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/inmunología , Drosophila melanogaster/inmunología , Infecciones por Enterobacteriaceae/inmunología , Enterobacteriaceae/fisiología , Cuerpo Adiposo/inmunología , Intestinos/inmunología , Estrés Oxidativo , Animales , Modelos Animales de Enfermedad , Drosophila melanogaster/genética , Drosophila melanogaster/microbiología , Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/microbiología , Infecciones por Enterobacteriaceae/fisiopatología , Cuerpo Adiposo/fisiopatología , Humanos , Intestinos/microbiología , Intestinos/fisiopatología , Óxido Nítrico/inmunología , Especies Reactivas de Oxígeno/inmunología
8.
Appl Microbiol Biotechnol ; 81(3): 523-32, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18810430

RESUMEN

A novel microbial transglutaminase (TGase) from the cultural filtrate of Streptomyces netropsis BCRC 12429 (Sn) was purified. The specific activity of the purified TGase was 18.2 U/mg protein with an estimated molecular mass of 38 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The TGase gene of S. netropsis was cloned and an open reading frame of 1,242 bp encoding a protein of 413 amino acids was identified. The Sn TGase was synthesized as a precursor protein with a preproregion of 82 amino acid residues. The deduced amino acid sequence of the mature S. netropsis TGase shares 78.9-89.6% identities with TGases from Streptomyces spp. A high level of soluble Sn TGase with its N-terminal propeptide fused with thioredoxin was expressed in E. coli. A simple and efficient process was applied to convert the purified recombinant protein into an active enzyme and showed activity equivalent to the authentic mature TGase.


Asunto(s)
Proteínas Bacterianas/metabolismo , Escherichia coli/genética , Expresión Génica , Streptomyces/enzimología , Transglutaminasas/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/aislamiento & purificación , Secuencia de Bases , Clonación Molecular , Estabilidad de Enzimas , Escherichia coli/metabolismo , Datos de Secuencia Molecular , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Transglutaminasas/química , Transglutaminasas/genética , Transglutaminasas/aislamiento & purificación
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