RESUMO
Zika virus (ZIKV), the causative agent of Zika fever, is a flavivirus transmitted by mosquitoes of the Aedes genus. Zika virus infection has become an international concern due to its association with severe neurological complications such as fetal microcephaly. Viral infection can induce the release of ATP in the extracellular environment, activating receptors sensitized by extracellular nucleotides, such as the P2X7 receptor. This receptor is the primary purinergic receptor involved in neuroinflammation, neurodegeneration, and immunity. In this work, we investigated the role of ATP-P2X7 receptor signaling in Zika-related brain abnormalities. Wild-type mice (WT) and P2X7 receptor-deficient (P2X7-/-) C57BL/6 newborn mice were subcutaneously inoculated with 5 × 106plaque-forming units of ZIKV or mock solution. P2X7 receptor expression increased in the brain of Zika virus-infected mice compared to the mock group. Comparative analyses of the hippocampi from WT and P2X7-/-mice revealed that the P2X7 receptor increased hippocampal damage in CA1/CA2 and CA3 regions. Doublecortin expression decreased significantly in the brains of ZIKV-infected mice. WT ZIKV-infected mice showed impaired motor performance compared to P2X7-/- infected mice. WT ZIKV-infected animals showed increased expression of glial markers GFAP (astrocytes) and IBA-1 (microglia) compared to P2X7-/- infected mice. Although the P2X7 receptor contributes to neuronal loss and neuroinflammation, WT mice were more efficient in controlling the viral load in the brain than P2X7 receptor-deficient mice. This result was associated with higher induction of TNF-α, IFN-ß, and increased interferon-stimulated gene expression in WT mice than P2X7-/-ZIKV-infected. Finally, we found that the P2X7 receptor contributes to inhibiting the neuroprotective signaling pathway AKT/mTOR while stimulating the caspase-3 activation, possibly two distinct pathways contributing to neurodegeneration. These findings suggest that ATP-P2X7 receptor signaling contributes to the antiviral response in the brain of ZIKV-infected mice while increasing neuronal loss, neuroinflammation, and related brain abnormalities.
Assuntos
Infecção por Zika virus , Zika virus , Gravidez , Feminino , Animais , Camundongos , Zika virus/genética , Doenças Neuroinflamatórias , Receptores Purinérgicos P2X7/genética , Receptores Purinérgicos P2X7/metabolismo , Camundongos Endogâmicos C57BL , Encéfalo/metabolismo , Transdução de Sinais , Trifosfato de AdenosinaRESUMO
Zika virus (ZIKV) infection became a worldwide concern due to its correlation with the development of microcephaly and other neurological disorders. ZIKV neurotropism is well characterized, but the role of peripheral viral amplification to brain infection remains unknown. Here, we found that ZIKV replicates in human primary skeletal muscle myoblasts, impairing its differentiation into myotubes but not interfering with the integrity of the already-formed muscle fibers. Using mouse models, we showed ZIKV tropism to muscle tissue either during embryogenesis after maternal transmission or when infection occurred after birth. Interestingly, ZIKV replication in the mouse skeletal muscle started immediately after ZIKV inoculation, preceding viral RNA detection in the brain and causing no disruption to the integrity of the blood brain barrier, and remained active for more than 2 weeks, whereas replication in the spleen and liver were not sustained over time. In addition, ZIKV infection of the skeletal muscle induces necrotic lesions, inflammation, and fiber atrophy. We also found a reduction in the expression of regulatory myogenic factors that are essential for muscle repair after injury. Taken together, our results indicate that the skeletal muscle is an early site of viral amplification and lesion that may result in late consequences in muscle development after ZIKV infection. IMPORTANCE Zika Virus (ZIKV) neurotropism and its deleterious effects on central nervous system have been well characterized. However, investigations of the initial replication sites for the establishment of infection and viral spread to neural tissues remain underexplored. A complete description of the range of ZIKV-induced lesions and others factors that can influence the severity of the disease is necessary to prevent ZIKV's deleterious effects. ZIKV has been shown to access the central nervous system without significantly affecting blood-brain barrier permeability. Here, we demonstrated that skeletal muscle is an earlier site of ZIKV replication, contributing to the increase of peripheral ZIKV load. ZIKV replication in muscle promotes necrotic lesions and inflammation and also impairs myogenesis. Overall, our findings showed that skeletal muscle is involved in pathogenesis and opens new fields in the investigation of the long-term consequences of early infection.
Assuntos
Fibras Musculares Esqueléticas/virologia , Infecção por Zika virus/virologia , Zika virus/fisiologia , Aedes , Animais , Animais Recém-Nascidos , Linhagem Celular , Feminino , Humanos , Transmissão Vertical de Doenças Infecciosas , Camundongos , Camundongos Knockout , Fibras Musculares Esqueléticas/citologia , Mioblastos , Replicação ViralRESUMO
INTRODUCTION: The methanol (MeOH) leaf extracts of the species Faramea bahiensis, F. hyacinthina and F. truncata (Rubiaceae) have previously shown in vitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activities in human hepatocarcinoma cell lineage (HepG2). Chemical studies have led to the isolation of major flavonoids, but quite complex fractions of phenolic compounds still remain. OBJECTIVE: To complete the study of phenolic compounds in the leaves and to access the presence of these compounds in the stems of these Faramea spp. by online high-performance liquid chromatography-diode array detector-electrospray ionisation tandem mass spectrometry (HPLC-DAD-ESI-MS/MS), as well as to evaluate the in vitro cytotoxic and anti-DENV2 activities of their MeOH stem extracts. METHODOLOGY: The identification was performed by comparing retention times, UV and mass spectra with those of available standards and by using the mechanisms and fragmentation patterns established in previous studies. The effects of the extracts in DENV2 infected HepG2 cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The virus titer was quantified by plaque assay. RESULTS: The study led to the characterisation of 31 phenolic compounds including flavonoid O- and C-glycosides, phenolic acids and one coumarin. The stem extracts from F. hyacinthina and F. bahiensis presented a similar bioactivity to those of their leaves but a loss of cytoprotective activity of F. bahiensis and a higher cytotoxicity of F. truncata were observed. CONCLUSIONS: This research allowed a detailed phenolic composition of three bioactive Faramea species to be achieved, thus contributing to the study of this genus and providing valuable information for further phytotherapeutic applications.
Assuntos
Antivirais/farmacologia , Cromatografia Líquida de Alta Pressão/métodos , Vírus da Dengue/efeitos dos fármacos , Folhas de Planta/química , Caules de Planta/química , Polifenóis/análise , Polifenóis/farmacologia , Rubiaceae/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Animais , Brasil , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Flavonoides/análise , Flavonoides/farmacologia , Células Hep G2 , Humanos , Sais de Tetrazólio/química , Tiazóis/químicaRESUMO
The defatted fractions of the Faramea hyacinthina and F. truncata (Rubiaceae) leaf MeOH extracts showed in vitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). Submitting these fractions to the developed RP-SPE method allowed isolating the antiviral flavanone (2S)-isosakuranetin-7-O-ß-d-apiofuranosyl-(1â6)-ß-d-glucopyranoside (1) from both species and yielded less active sub-fractions. The new diastereoisomeric epimer pair (2S) + (2R) of 5,3',5'-trihydroxyflavanone-7-O-ß-d-apiofuranosyl-(1â6)-ß-d-glucopyranoside (2a/2b) from F. hyacinthina; the known narigenin-7-O-ß-d-apiofuranosyl-(1â6)-ß-d-glucopyranoside (3) from both species; rutin (4) and quercetin-4'-ß-d-O-glucopyranosyl-3-O-rutinoside (5) from F. hyacinthina, and kaempferol-3-O-rutinoside (6), erythroxyloside A (7) and asperuloside (8) from F. truncata have been isolated from these sub-fractions. Compounds 4 - 8 are reported for the first time in Faramea spp.
Assuntos
Antivirais/farmacologia , Vírus da Dengue/efeitos dos fármacos , Dengue/tratamento farmacológico , Componentes Aéreos da Planta/química , Rubiaceae/química , Antivirais/química , Antivirais/isolamento & purificação , Sobrevivência Celular/efeitos dos fármacos , Dengue/virologia , Relação Dose-Resposta a Droga , Células Hep G2 , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Folhas de Planta/química , Especificidade da Espécie , Relação Estrutura-AtividadeRESUMO
Endostatin is a potent anti-angiogenic and anti-tumor protein capable of regressing tumors without inducing acquired resistance. Since it is a fragment of the parental molecule, collagen XVIII, its endogenous production depends on the activity of a specific proteolytic enzyme. While such an enzyme has been described in mice, a human counterpart has not been identified so far. Here, we searched for this enzyme by using a fluorescence resonance energy transfer peptide containing the cleavage site of human collagen XVIII. We found that the cleavage activity was present in various murine and human tumor cells but not in untransformed cells. It was ascribed to a large protein complex identified as an extracellular form of proteasome 20S. Since circulating proteasome 20S has recently emerged as an important marker of tumor progression, the possibility of proteasomes controlling the production of angiostatic endostatin may inspire the development of new anticancer therapies.
Assuntos
Colágeno Tipo XVIII/metabolismo , Endostatinas/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Colágeno Tipo XVIII/química , Espaço Extracelular/enzimologia , Transferência Ressonante de Energia de Fluorescência , Hemangioendotelioma/patologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Camundongos , Peptídeos/metabolismo , Subunidades Proteicas/metabolismo , ProteóliseRESUMO
Virus resistance to antiviral therapies is an increasing concern that makes the development of broad-spectrum antiviral drugs urgent. Targeting of the viral envelope, a component shared by a large number of viruses, emerges as a promising strategy to overcome this problem. Natural and synthetic porphyrins are good candidates for antiviral development due to their relative hydrophobicity and pro-oxidant character. In the present work, we characterized the antiviral activities of protoprophyrin IX (PPIX), Zn-protoporphyrin IX (ZnPPIX), and mesoporphyrin IX (MPIX) against vesicular stomatitis virus (VSV) and evaluated the mechanisms involved in this activity. Treatment of VSV with PPIX, ZnPPIX, and MPIX promoted dose-dependent virus inactivation, which was potentiated by porphyrin photoactivation. All three porphyrins inserted into lipid vesicles and disturbed the viral membrane organization. In addition, the porphyrins also affected viral proteins, inducing VSV glycoprotein cross-linking, which was enhanced by porphyrin photoactivation. Virus incubation with sodium azide and α-tocopherol partially protected VSV from inactivation by porphyrins, suggesting that singlet oxygen (1O2) was the main reactive oxygen species produced by photoactivation of these molecules. Furthermore, 1O2 was detected by 9,10-dimethylanthracene oxidation in photoactivated porphyrin samples, reinforcing this hypothesis. These results reveal the potential therapeutic application of PPIX, ZnPPIX, and MPIX as good models for broad antiviral drug design.
Assuntos
Antivirais/farmacologia , Mesoporfirinas/farmacologia , Protoporfirinas/farmacologia , Vírus da Estomatite Vesicular Indiana/efeitos dos fármacos , Animais , Antracenos/química , Linhagem Celular , Cricetinae , Farmacorresistência Viral , Mesoporfirinas/química , Protoporfirinas/química , Oxigênio Singlete/química , Azida Sódica/farmacologia , Inativação de Vírus/efeitos dos fármacos , alfa-Tocoferol/farmacologiaRESUMO
Alphaviruses among the viruses that cause arthritis, consisting in a public health problem worldwide by causing localized outbreaks, as well as large epidemics in humans. Interestingly, while the Old World alphaviruses are arthritogenic, the New World alphaviruses cause encephalitis. One exception is Mayaro virus (MAYV), which circulates exclusively in South America but causes arthralgia and is phylogenetically related to the Old World alphaviruses. Although MAYV-induced arthritis in humans is well documented, the molecular and cellular factors that contribute to its pathogenesis are completely unknown. In this study, we demonstrated for the first time that macrophages, key players in arthritis development, are target cells for MAYV infection, which leads to cell death through apoptosis. We showed that MAYV replication in macrophage induced the expression of TNF, a cytokine that would contribute to pathogenesis of MAYV fever, since TNF promotes an inflammatory profile characteristic of arthritis. We also found a significant increase in the production of reactive oxygen species (ROS) at early times of infection, which coincides with the peak of virus replication and precedes TNF secretion. Treatment of the cells with antioxidant agents just after infection completely abolished TNF secretion, indicating an involvement of ROS in inflammation induced during MAYV infection.
Assuntos
Infecções por Alphavirus , Artrite/virologia , Macrófagos/virologia , Espécies Reativas de Oxigênio/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Replicação Viral , Infecções por Alphavirus/complicações , Humanos , América do SulRESUMO
Zika virus (ZIKV) is a neurotropic Orthoflavivirus that causes a myriad of neurological manifestations in newborns exposed in uterus. Despite the devastating consequences of ZIKV on the developing brain, strategies to prevent or treat the consequences of viral infection are not yet available. We previously showed that short-term treatment with the TNF-α neutralizing monoclonal antibody. Infliximab could prevent seizures at acute and chronic stages of ZIKV infection, but had no impact on long-term cognitive and motor dysfunction. Due to the central role of inflammation in ZIKV-neuropathology, we hypothesized that prolonged treatment with the anti-TNF-α monoclonal antibody Infliximab could provide complete rescue of long-term behavioral deficits associated with neonatal ZIKV infection in mice. Here, neonatal (post-natal day 3) Swiss mice were submitted to subcutaneous (s.c.) injection of 106 PFU of ZIKV or mock medium and were then treated with Infliximab (20⯵g/day) or sterile saline intraperitoneally (i.p.), for 40 days starting on the day of infection, and behavioral assessment started at 60 days post-infection (dpi). Infliximab prevented ZIKV-induced cognitive and motor impairments in mice. In addition, microgliosis and cell death found in mice following ZIKV infection were partially reversed by TNF-α blockage. Altogether, these results suggest that TNF-α-mediated inflammation is central for late ZIKV-induced behavioral deficits and cell death and strategies targeting this cytokine may be promising approaches to treat subjects exposed to the virus during development.
Assuntos
Modelos Animais de Doenças , Infliximab , Fator de Necrose Tumoral alfa , Infecção por Zika virus , Animais , Infecção por Zika virus/complicações , Camundongos , Infliximab/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Comportamento Animal/efeitos dos fármacos , Animais Recém-Nascidos , Zika virus/efeitos dos fármacos , Masculino , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/tratamento farmacológico , FemininoRESUMO
Zika virus (ZIKV) is a neurotropic flavivirus that can persist in several tissues. The late consequences of ZIKV persistence and whether new rounds of active replication can occur, remain unaddressed. Here, we investigated whether neonatally ZIKV-infected mice are susceptible to viral reactivation in adulthood. We found that when ZIKV-infected mice are treated with immunosuppressant drugs, they present increased susceptibility to chemically induced seizures. Levels of subgenomic flavivirus RNAs (sfRNAs) were increased, relative to the amounts of genomic RNAs, in the brains of mice following immunosuppression and were associated with changes in cytokine expression. We investigated the impact of immunosuppression on the testicles and found that ZIKV genomic RNA levels are increased in mice following immunosuppression, which also caused significant testicular damage. These findings suggest that ZIKV can establish new rounds of active replication long after acute stages of disease, so exposed patients should be monitored to ensure complete viral eradication.
RESUMO
Zika virus (ZIKV) infection was first associated with Central Nervous System (CNS) infections in Brazil in 2015, correlated with an increased number of newborns with microcephaly, which ended up characterizing the Congenital Zika Syndrome (CZS). Here, we investigated the impact of ZIKV infection on the functionality of iPSC-derived astrocytes. Besides, we extrapolated our findings to a Brazilian cohort of 136 CZS children and validated our results using a mouse model. Interestingly, ZIKV infection in neuroprogenitor cells compromises cell migration and causes apoptosis but does not interfere in astrocyte generation. Moreover, infected astrocytes lost their ability to uptake glutamate while expressing more glutamate transporters and secreted higher levels of IL-6. Besides, infected astrocytes secreted factors that impaired neuronal synaptogenesis. Since these biological endophenotypes were already related to Autism Spectrum Disorder (ASD), we extrapolated these results to a cohort of children, now 6-7 years old, and found seven children with ASD diagnosis (5.14 %). Additionally, mice infected by ZIKV revealed autistic-like behaviors, with a significant increase of IL-6 mRNA levels in the brain. Considering these evidence, we inferred that ZIKV infection during pregnancy might lead to synaptogenesis impairment and neuroinflammation, which could increase the risk for ASD.
Assuntos
Astrócitos , Transtorno do Espectro Autista , Doenças Neuroinflamatórias , Sinapses , Infecção por Zika virus , Zika virus , Infecção por Zika virus/patologia , Infecção por Zika virus/metabolismo , Infecção por Zika virus/virologia , Infecção por Zika virus/complicações , Transtorno do Espectro Autista/virologia , Transtorno do Espectro Autista/metabolismo , Transtorno do Espectro Autista/etiologia , Transtorno do Espectro Autista/patologia , Humanos , Animais , Camundongos , Zika virus/fisiologia , Feminino , Criança , Sinapses/metabolismo , Sinapses/patologia , Doenças Neuroinflamatórias/virologia , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/patologia , Doenças Neuroinflamatórias/etiologia , Astrócitos/virologia , Astrócitos/metabolismo , Astrócitos/patologia , Masculino , Interleucina-6/metabolismo , Interleucina-6/genética , Gravidez , Fatores de Risco , Células-Tronco Pluripotentes Induzidas/virologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Brasil/epidemiologia , Modelos Animais de Doenças , NeurogêneseRESUMO
Wallerian degeneration (WD) comprises a series of events that includes activation of non-neuronal cells and recruitment of immune cells, creating an inflammatory milieu that leads to extensive nerve fragmentation and subsequent clearance of the myelin debris, both of which are necessary prerequisites for effective nerve regeneration. Previously, we documented accelerated axon regeneration in animals lacking galectin-3 (Gal-3), a molecule associated with myelin clearance. To clarify the mechanisms underlying this enhanced regeneration, we focus here on the early steps of WD following sciatic nerve crush in Gal-3(-/-) mice. Using an in vivo model of nerve degeneration, we observed that removal of myelin debris is more efficient in Gal-3(-/-) than in wild-type (WT) mice; we next used an in vitro phagocytosis assay to document that the phagocytic potential of macrophages and Schwann cells was enhanced in the Gal-3(-/-) mice. Moreover, both RNA and protein levels for the pro-inflammatory cytokines IL-1ß and TNF-α, as well as for Toll-like receptor (TLR)-2 and -4, show robust increases in injured nerves from Gal-3(-/-) mice compared to those from WT mice. Collectively, these data indicate that the lack of Gal-3 results in an augmented inflammatory profile that involves the TLR-cytokine pathway, and increases the phagocytic capacity of Schwann cells and macrophages, which ultimately contributes to speeding the course of WD.
Assuntos
Citocinas/metabolismo , Galectina 3/genética , Nervo Isquiático/lesões , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Degeneração Walleriana/metabolismo , Animais , Citocinas/genética , Galectina 3/metabolismo , Macrófagos/metabolismo , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Bainha de Mielina/metabolismo , Compressão Nervosa , Fagocitose , Células de Schwann/metabolismo , Células de Schwann/fisiologia , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Transcrição Gênica , Degeneração Walleriana/genéticaRESUMO
Dengue virus (DENV) affects millions of people, causing more than 20,000 deaths annually. No effective treatment for the disease caused by DENV infection is currently available, partially due to the lack of knowledge on the basic aspects of the viral life cycle, including the molecular basis of the interaction between viral components and cellular compartments. Here, we characterized the properties of the interaction between the DENV capsid (C) protein and hepatic lipid droplets (LDs), which was recently shown to be essential for the virus replication cycle. Zeta potential analysis revealed a negative surface charge of LDs, with an average surface charge of -19 mV. The titration of LDs with C protein led to an increase of the surface charge, which reached a plateau at +13.7 mV, suggesting that the viral protein-LD interaction exposes the protein cationic surface to the aqueous environment. Atomic force microscopy (AFM)-based force spectroscopy measurements were performed by using C protein-functionalized AFM tips. The C protein-LD interaction was found to be strong, with a single (un)binding force of 33.6 pN. This binding was dependent on high intracellular concentrations of potassium ions but not sodium. The inhibition of Na(+)/K(+)-ATPase in DENV-infected cells resulted in the dissociation of C protein from LDs and a 50-fold inhibition of infectious virus production but not of RNA replication, indicating a biological relevance for the potassium-dependent interaction. Limited proteolysis of the LD surface impaired the C protein-LD interaction, and force measurements in the presence of specific antibodies indicated that perilipin 3 (TIP47) is the major DENV C protein ligand on the surface of LDs.
Assuntos
Proteínas do Capsídeo/metabolismo , Vírus da Dengue/metabolismo , Dengue/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Capsídeo/genética , Dengue/virologia , Vírus da Dengue/genética , Células Hep G2 , Humanos , Fígado/virologia , Potássio/metabolismo , Ligação ProteicaRESUMO
Chikungunya fever, a debilitating disease caused by Chikungunya virus (CHIKV), is characterized by a high fever of sudden onset and an intense arthralgia that impairs individual regular activities. Although most symptoms are self-limited, long-term persistent arthralgia is observed in 30-40% of infected individuals. Currently, there is no vaccine or specific treatment against CHIKV infection, so there is an urgent need for the discovery of new therapeutic options for CHIKF chronic cases. This present study aims to test the antiviral, cytoprotective, and anti-inflammatory activities of an ethanol extract (FF72) from Ampelozizyphus amazonicus Ducke wood, chemically characterized using mass spectrometry, which indicated the major presence of dammarane-type triterpenoid saponins. The major saponin in the extract, with a deprotonated molecule ion m/z 897 [M-H]-, was tentatively assigned as a jujubogenin triglycoside, a dammarane-type triterpenoid saponin. Treatment with FF72 resulted in a significant reduction in both virus replication and the production of infective virions in BHK-21-infected cells. The viability of infected cells was assessed using an MTT, and the result indicated that FF72 treatment was able to revert the toxicity mediated by CHIKV infection. In addition, FF72 had a direct effect on CHIKV, since the infectivity was completely abolished in the presence of the extract. FF72 treatment also reduced the expression of the major pro-inflammatory mediators overexpressed during CHIKV infection, such as IL-1ß, IL-6, IL-8, and MCP-1. Overall, the present study elucidates the potential of FF72 to become a promising candidate of herbal medicine for alphaviruses infections.
Assuntos
Febre de Chikungunya , Vírus Chikungunya , Saponinas , Triterpenos , Humanos , Febre de Chikungunya/tratamento farmacológico , Madeira , Triterpenos/farmacologia , Replicação Viral , Saponinas/farmacologia , Antivirais/farmacologia , Antivirais/uso terapêutico , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Etanol/farmacologia , Artralgia/tratamento farmacológico , DamaranosRESUMO
Co-use of marijuana and tobacco products is the second most common drug combination among adolescents. Nicotine (NIC) and cannabinoid use during adolescence induce similar detrimental changes, raising the hypothesis that simultaneous exposure could result in even more severe outcomes. Thus, we investigated whether the co-exposure to NIC and the synthetic cannabinoid WIN 55,212-2 (WIN) in adolescent mice causes behavioral outcomes different from those observed after exposure to a single drug. Male Swiss mice were exposed twice daily to NIC, WIN, or NIC + WIN during adolescence (PND28-47) or adulthood (PND70-89). Drug combination led to a greater reduction in weight gain in adolescent mice, while NIC-induced weight loss was observed in adults. During administration, NIC provoked hypothermia, and WIN produced hyperlocomotion in adolescent and adult mice. Animals exposed to NIC + WIN presented a profile of changes similar to those exposed to NIC. After drug exposure, changes in locomotion, thigmotaxis, social preference, prepulse inhibition, and working and recognition memory were evaluated. Adolescent but not adult mice exposed to NIC showed withdrawal-related hyperlocomotion unaffected by WIN co-administration. An age-specific impairment in object recognition memory was induced only by drug co-exposure during adolescence, which resolved spontaneously before reaching early adulthood. A transient decrease in hippocampal α7 nAChR subunit and CB1 receptor mRNA levels was induced by NIC exposure, which may be involved but is not enough to explain the memory impairment. Our work confirms the potential of NIC and cannabinoids association to aggravate some of the individual drug effects during critical neurodevelopmental periods.
Assuntos
Canabinoides , Nicotina , Camundongos , Masculino , Animais , Nicotina/farmacologia , Transtornos da Memória , Canabinoides/farmacologia , Reconhecimento Psicológico , Combinação de Medicamentos , Benzoxazinas/farmacologiaRESUMO
Zika virus (ZIKV) infection causes severe neurological consequences in both gestationally-exposed infants and adults. Sensorial gating deficits strongly correlate to the motor, sensorial and cognitive impairments observed in ZIKV-infected patients. However, no startle response or prepulse inhibition (PPI) assessment has been made in patients or animal models. In this study, we identified different outcomes according to the age of infection and sex in mice: neonatally infected animals presented an increase in PPI and delayed startle latency. However, adult-infected male mice presented lower startle amplitude, while a PPI impairment was observed 14 days after infection in both sexes. Our data further the understanding of the functional impacts of ZIKV on the developing and mature nervous system, which could help explain other behavioral and cognitive alterations caused by the virus. With this study, we support the startle reflex testing in ZIKV-exposed patients, especially infants, allowing for early detection of functional neuromotor damage and early intervention.
Assuntos
Infecção por Zika virus , Zika virus , Feminino , Masculino , Animais , Camundongos , Reflexo de Sobressalto/fisiologia , Inibição Pré-Pulso , Infecção por Zika virus/complicações , Estimulação AcústicaRESUMO
Brazil has the second-highest COVID-19 death rate worldwide, and Rio de Janeiro is among the states with the highest rate in the country. Although vaccine coverage has been achieved, it is anticipated that COVID-19 will transition into an endemic disease. It is concerning that the molecular mechanisms underlying clinical evolution from mild to severe disease, as well as the mechanisms leading to long COVID-19, are not yet fully understood. NMR and MS-based metabolomics were used to identify metabolites associated with COVID-19 pathophysiology and disease outcome. Severe COVID-19 cases (n = 35) were enrolled in two reference centers in Rio de Janeiro within 72 h of ICU admission, alongside 12 non-infected control subjects. COVID-19 patients were grouped into survivors (n = 18) and non-survivors (n = 17). Choline-related metabolites, serine, glycine, and betaine, were reduced in severe COVID-19, indicating dysregulation in methyl donors. Non-survivors had higher levels of creatine/creatinine, 4-hydroxyproline, gluconic acid, and N-acetylserine, indicating liver and kidney dysfunction. Several changes were greater in women; thus, patients' sex should be considered in pandemic surveillance to achieve better disease stratification and improve outcomes. These metabolic alterations may be useful to monitor organ (dys) function and to understand the pathophysiology of acute and possibly post-acute COVID-19 syndromes.
RESUMO
Dengue virus is responsible for the highest rates of disease and mortality among the members of the Flavivirus genus. Dengue epidemics are still occurring around the world, indicating an urgent need of prophylactic vaccines and antivirals. In recent years, a great deal has been learned about the mechanisms of dengue virus genome amplification. However, little is known about the process by which the capsid protein recruits the viral genome during encapsidation. Here, we found that the mature capsid protein in the cytoplasm of dengue virus infected cells accumulates on the surface of ER-derived organelles named lipid droplets. Mutagenesis analysis using infectious dengue virus clones has identified specific hydrophobic amino acids, located in the center of the capsid protein, as key elements for lipid droplet association. Substitutions of amino acid L50 or L54 in the capsid protein disrupted lipid droplet targeting and impaired viral particle formation. We also report that dengue virus infection increases the number of lipid droplets per cell, suggesting a link between lipid droplet metabolism and viral replication. In this regard, we found that pharmacological manipulation of the amount of lipid droplets in the cell can be a means to control dengue virus replication. In addition, we developed a novel genetic system to dissociate cis-acting RNA replication elements from the capsid coding sequence. Using this system, we found that mislocalization of a mutated capsid protein decreased viral RNA amplification. We propose that lipid droplets play multiple roles during the viral life cycle; they could sequester the viral capsid protein early during infection and provide a scaffold for genome encapsidation.
Assuntos
Proteínas do Capsídeo/farmacologia , Vírus da Dengue/fisiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos de Membrana/metabolismo , Vírion/metabolismo , Montagem de Vírus/efeitos dos fármacos , Motivos de Aminoácidos/genética , Motivos de Aminoácidos/fisiologia , Animais , Transporte Biológico/efeitos dos fármacos , Proteínas do Capsídeo/química , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Células Cultivadas , Cricetinae , Dengue/metabolismo , Dengue/virologia , Vírus da Dengue/genética , Vírus da Dengue/metabolismo , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Modelos Biológicos , Modelos Moleculares , Proteínas Mutantes/metabolismo , Proteínas Mutantes/fisiologia , Multimerização Proteica , Estrutura Secundária de Proteína/genética , RNA Viral/metabolismoRESUMO
Dengue fever is an emerging viral disease transmitted by arthropods to humans in tropical countries. Dengue hemorrhagic fever (DHF) is escalating in frequency and mortality rates. Here we studied the involvement of macrophage migration inhibitory factor (MIF) in dengue virus (DENV) infection and its pathogenesis. Patients with DHF had elevated plasma concentrations of MIF. Both leukocytes from these patients and macrophages from healthy donors infected in vitro with DENV showed a substantial amount of MIF within lipid droplets. The secretion of MIF by macrophages and hepatocytes required a productive infection and occurred without an increase in gene transcription or cell death, thus indicating active secretion from preformed stocks. In vivo infection of wild-type and mif-deficient (Mif(-/-)) mice demonstrated a role of MIF in dengue pathogenesis. Clinical disease was less severe in Mif(-/-) mice, and they exhibited a significant delay in lethality, lower viremia, and lower viral load in the spleen than wild-type mice. This reduction in all parameters of severity on DENV infection in Mif(-/-) mice correlated with reduced proinflammatory cytokine concentrations. These results demonstrated the contribution of MIF to the pathogenesis of dengue and pointed to a possible beneficial role of neutralizing MIF as an adjunctive therapeutic approach to treat the severe forms of the disease.
Assuntos
Dengue/etiologia , Oxirredutases Intramoleculares/fisiologia , Fatores Inibidores da Migração de Macrófagos/fisiologia , Animais , Sequência de Bases , Citocinas/biossíntese , Citocinas/genética , Primers do DNA/genética , Dengue/sangue , Dengue/genética , Dengue/fisiopatologia , Dengue/terapia , Vírus da Dengue/patogenicidade , Modelos Animais de Doenças , Expressão Gênica , Hepatócitos/fisiologia , Hepatócitos/virologia , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Técnicas In Vitro , Mediadores da Inflamação/metabolismo , Oxirredutases Intramoleculares/sangue , Oxirredutases Intramoleculares/deficiência , Oxirredutases Intramoleculares/genética , Leucócitos/metabolismo , Metabolismo dos Lipídeos , Fatores Inibidores da Migração de Macrófagos/sangue , Fatores Inibidores da Migração de Macrófagos/deficiência , Fatores Inibidores da Migração de Macrófagos/genética , Macrófagos/fisiologia , Macrófagos/virologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Estudos Prospectivos , Dengue Grave/etiologia , Dengue Grave/genética , Dengue Grave/fisiopatologiaRESUMO
Besides antigen-specific responses to viral antigens, humoral immune response in virus infection can generate polyreactive and autoreactive antibodies. Dengue and Zika virus infections have been linked to antibody-mediated autoimmune disorders, including Guillain-Barré syndrome. A unique feature of flaviviruses is the secretion of nonstructural protein 1 (NS1) by infected cells. NS1 is highly immunogenic, and antibodies targeting NS1 can have both protective and pathogenic roles. In the present study, we investigated the humoral immune response to Zika virus NS1 and found NS1 to be an immunodominant viral antigen associated with the presence of autoreactive antibodies. Through single B cell cultures, we coupled binding assays and BCR sequencing, confirming the immunodominance of NS1. We demonstrate the presence of self-reactive clones in germinal centers after both infection and immunization, some of which present cross-reactivity with NS1. Sequence analysis of anti-NS1 B cell clones showed sequence features associated with pathogenic autoreactive antibodies. Our findings demonstrate NS1 immunodominance at the cellular level as well as a potential role for NS1 in ZIKV-associated autoimmune manifestations.
Assuntos
Reações Cruzadas/imunologia , Proteínas não Estruturais Virais/imunologia , Infecção por Zika virus/imunologia , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Linfócitos B/virologia , Feminino , Centro Germinativo/patologia , Centro Germinativo/virologia , Imunização , Imunoglobulina M/sangue , Camundongos Endogâmicos BALB C , Proteínas não Estruturais Virais/sangue , Infecção por Zika virus/virologiaRESUMO
Zika virus (ZIKV) emerged as an important infectious disease agent in Brazil in 2016. Infection usually leads to mild symptoms, but severe congenital neurological disorders and Guillain-Barré syndrome have been reported following ZIKV exposure. Creating an effective vaccine against ZIKV is a public health priority. We describe the protective effect of an already licensed attenuated yellow fever vaccine (YFV, 17DD) in type-I interferon receptor knockout mice (A129) and immunocompetent BALB/c and SV-129 (A129 background) mice infected with ZIKV. YFV vaccination provided protection against ZIKV, with decreased mortality in A129 mice, a reduction in the cerebral viral load in all mice, and weight loss prevention in BALB/c mice. The A129 mice that were challenged two and three weeks after the first dose of the vaccine were fully protected, whereas partial protection was observed five weeks after vaccination. In all cases, the YFV vaccine provoked a substantial decrease in the cerebral viral load. YFV immunization also prevented hippocampal synapse loss and microgliosis in ZIKV-infected mice. Our vaccine model is T cell-dependent, with AG129 mice being unable to tolerate immunization (vaccination is lethal in this mouse model), indicating the importance of IFN-γ in immunogenicity. To confirm the role of T cells, we immunized nude mice that we demonstrated to be very susceptible to infection. Immunization with YFV and challenge 7 days after booster did not protect nude mice in terms of weight loss and showed partial protection in the survival curve. When we evaluated the humoral response, the vaccine elicited significant antibody titers against ZIKV; however, it showed no neutralizing activity in vitro and in vivo. The data indicate that a cell-mediated response promotes protection against cerebral infection, which is crucial to vaccine protection, and it appears to not necessarily require a humoral response. This protective effect can also be attributed to innate factors, but more studies are needed to strengthen this hypothesis. Our findings open the way to using an available and inexpensive vaccine for large-scale immunization in the event of a ZIKV outbreak.