RESUMEN

In the context of the virosphere, viral particles can compete for host cells. In this scenario, some viruses block the entry of exogenous virions upon infecting a cell, a phenomenon known as superinfection inhibition. The molecular mechanisms associated with superinfection inhibition vary depending on the viral species and the host, but generally, blocking superinfection ensures the genetic supremacy of the virus's progeny that first infects the cell. Giant amoeba-infecting viruses have attracted the scientific community's attention due to the complexity of their particles and genomes. However, there are no studies on the occurrence of superinfection and its inhibition induced by giant viruses. This study shows that mimivirus, moumouvirus, and megavirus, exhibit different strategies related to the infection of Acanthamoeba. For the first time, we have reported that mimivirus and moumouvirus induce superinfection inhibition in amoebas. Interestingly, megaviruses do not exhibit this ability, allowing continuous entry of exogenous virions into infected amoebas. Our investigation into the mechanisms behind superinfection blockage reveals that mimivirus and moumouvirus inhibit amoebic phagocytosis, leading to significant changes in the morphology and activity of the host cells. In contrast, megavirus-infected amoebas continue incorporating newly formed virions, negatively affecting the available viral progeny. This effect, however, is reversible with chemical inhibition of phagocytosis. This work contributes to the understanding of superinfection and its inhibition in mimivirus, moumouvirus, and megavirus, demonstrating that despite their evolutionary relatedness, these viruses exhibit profound differences in their interactions with their hosts.IMPORTANCESome viruses block the entry of new virions upon infecting a cell, a phenomenon known as superinfection inhibition. Superinfection inhibition in giant viruses has yet to be studied. This study reveals that even closely related viruses, such as mimivirus, moumouvirus, and megavirus, have different infection strategies for Acanthamoeba. For the first time, we have reported that mimivirus and moumouvirus induce superinfection inhibition in amoebas. In contrast, megaviruses do not exhibit this ability, allowing continuous entry of exogenous virions into infected amoebas. Our investigation shows that mimivirus and moumouvirus inhibit amoebic phagocytosis, causing significant changes in host cell morphology and activity. Megavirus-infected amoebas, however, continue incorporating newly formed viruses, affecting viral progeny. This research enhances our understanding of superinfection inhibition in these viruses, highlighting their differences in host interactions.

Asunto(s)

Acanthamoeba , Virus Gigantes , Mimiviridae , Fagocitosis , Sobreinfección , Sobreinfección/virología , Sobreinfección/inmunología , Acanthamoeba/virología , Virus Gigantes/fisiología , Virus Gigantes/genética , Mimiviridae/fisiología , Mimiviridae/genética , Internalización del Virus , Virión , Regulación hacia Abajo

RESUMEN

Arthritis and periodontitis are inflammatory diseases that share several immunopathogenic features. The expansion in the study of virus-induced arthritis has shed light on how this condition could impact other parts of the human body, including the mouth. Viral arthritis is an inflammatory joint disease caused by several viruses, most notably the alphaviruses Chikungunya virus (CHIKV), Sindbis virus (SINV), Ross River virus (RRV), Mayaro virus (MAYV), and O'nyong'nyong virus (ONNV). These viruses can induce an upsurge of matrix metalloproteinases and immune-inflammatory mediators such as Interleukin-6 (IL6), IL-1ß, tumor necrosis factor, chemokine ligand 2, and receptor activator of nuclear factor kappa-B ligand in the joint and serum of infected individuals. This can lead to the influx of inflammatory cells to the joints and associated muscles as well as osteoclast activation and differentiation, culminating in clinical signs of swelling, pain, and bone resorption. Moreover, several data indicate that these viral infections can affect other sites of the body, including the mouth. The human oral cavity is a rich and diverse microbial ecosystem, and viral infection can disrupt the balance of microbial species, causing local dysbiosis. Such events can result in oral mucosal damage and gingival bleeding, which are indicative of periodontitis. Additionally, infection by RRV, CHIKV, SINV, MAYV, or ONNV can trigger the formation of osteoclasts and upregulate pro-osteoclastogenic inflammatory mediators, interfering with osteoclast activation. As a result, these viruses may be linked to systemic conditions, including oral manifestations. Therefore, this review focuses on the involvement of alphavirus infections in joint and oral health, acting as potential agents associated with oral mucosal inflammation and alveolar bone loss. The findings of this review demonstrate how alphavirus infections could be linked to the comorbidity between arthritis and periodontitis and may provide a better understanding of potential therapeutic management for both conditions.

Asunto(s)

Infecciones por Alphavirus , Artritis , Virus Chikungunya , Periodontitis , Humanos , Infecciones por Alphavirus/tratamiento farmacológico , Infecciones por Alphavirus/patología , Virus Chikungunya/fisiología , Mediadores de Inflamación/uso terapéutico , Ligandos , Virus del Río Ross/fisiología

RESUMEN

Zika virus (ZIKV) is an arbovirus whose infection in humans can lead to severe outcomes. This article reviews studies reporting the anti-ZIKV activity of natural products (NPs) and derivatives published from 1997 to 2022, which were carried out with NPs obtained from plants (82.4%) or semisynthetic/synthetic derivatives, fungi (3.1%), bacteria (7.6%), animals (1.2%) and marine organisms (1.9%) along with miscellaneous compounds (3.8%). Classes of NPs reported to present anti-ZIKV activity include polyphenols, triterpenes, alkaloids, and steroids, among others. The highest values of the selectivity index, the ratio between cytotoxicity and antiviral activity (SI = CC50/EC50), were reported for epigallocatechin gallate (SI ≥ 25,000) and anisomycin (SI ≥ 11,900) obtained from Streptomyces bacteria, dolastane (SI = 1246) isolated from the marine seaweed Canistrocarpus cervicorni, and the flavonol myricetin (SI ≥ 862). NPs mostly act at the stages of viral adsorption and internalization in addition to presenting virucidal effect. The data demonstrate the potential of NPs for developing new anti-ZIKV agents and highlight the lack of studies addressing their molecular mechanisms of action and pre-clinical studies of efficacy and safety in animal models. To the best of our knowledge, none of the active compounds has been submitted to clinical studies.

Asunto(s)

Productos Biológicos , Infección por el Virus Zika , Virus Zika , Humanos , Animales , Chlorocebus aethiops , Células Vero , Productos Biológicos/farmacología , Productos Biológicos/uso terapéutico , Replicación Viral , Antivirales/farmacología , Antivirales/uso terapéutico

RESUMEN

The blood levels of neutrophils are associated with the severity of COVID -19. However, their role in the pulmonary environment during COVID -19 severity is not clear. Here, we found a decrease in the neutrophil count in BAL (bronchoalveolar lavage) in non-survivors and in older patients (> 60 years). In addition, we have shown that older patients have higher serum concentration of CXCL8 and increased IL-10 expression by neutrophils.

Asunto(s)

COVID-19 , Neutrófilos , Humanos , Anciano , Líquido del Lavado Bronquioalveolar , Pulmón , Pronóstico

RESUMEN

Cryptococcosis is an invasive mycosis caused by Cryptococcus spp. that affects the lungs and the central nervous system (CNS). Due to the severity of the disease, it may occur concomitantly with other pathogens, as a coinfection. Pseudomonas aeruginosa (Pa), an opportunistic pathogen, can also cause pneumonia. In this work, we studied the interaction of C. gattii (Cg) and Pa, both in vitro and in vivo. Pa reduced growth of Cg by the secretion of inhibitory molecules in vitro. Macrophages previously stimulated with Pa presented increased fungicidal activity. In vivo, previous Pa infection reduced morbidity and delayed the lethality due to cryptococcosis. This phenotype was correlated with the decreased fungal burden in the lungs and brain, showing a delay of Cg translocation to the CNS. Also, there was increased production of IL-1ß, CXCL-1, and IL-10, together with the influx of iNOS-positive macrophages and neutrophils to the lungs. Altogether, Pa turned the lung into a hostile environment to the growth of a secondary pathogen, making it difficult for the fungus to translocate to the CNS. Further, iNOS inhibition reverted the Pa protective phenotype, suggesting its important role in the coinfection. Altogether, the primary Pa infection leads to balanced pro-inflammatory and anti-inflammatory responses during Cg infection. This response provided better control of cryptococcosis and was decisive for the mild evolution of the disease and prolonged survival of coinfected mice in a mechanism dependent on iNOS.

Asunto(s)

Coinfección , Criptococosis , Cryptococcus gattii , Cryptococcus neoformans , Infecciones por Pseudomonas , Animales , Criptococosis/microbiología , Ratones , Fagocitosis

RESUMEN

Zika virus (ZIKV) infection is a global threat associated to neurological disorders in adults and microcephaly in children born to infected mothers. No vaccine or drug is available against ZIKV. We herein report the anti-ZIKV activity of 36 plant extracts containing polyphenols and/or triterpenes. ZIKV-infected Vero CCL-81 cells were treated with samples at non-cytotoxic concentrations, determined by MTT and LDH assays. One third of the extracts elicited concentration-dependent anti-ZIKV effect, with viral loads reduction from 0.4 to 3.8 log units. The 12 active extracts were tested on ZIKV-infected SH-SY5Y cells and significant reductions of viral loads (in log units) were induced by Maytenus ilicifolia (4.5 log), Terminalia phaeocarpa (3.7 log), Maytenus rigida (1.7 log) and Echinodorus grandiflorus (1.7 log) extracts. Median cytotoxic concentration (CC50 ) of these extracts in Vero cells were higher than in SH-SY5Y lineage. M. ilicifolia (IC50 =16.8±10.3 µg/mL, SI=3.4) and T. phaeocarpa (IC50 =22.0±6.8 µg/mL, SI=4.8) were the most active extracts. UPLC-ESI-MS/MS analysis of M. ilicifolia extract led to the identification of 7 triterpenes, of which lupeol and a mixture of friedelin/friedelinol showed no activity against ZIKV. The composition of T. phaeocarpa extract comprises phenolic acids, ellagitannins and flavonoids, as recently reported by us. In conclusion, the anti-ZIKV activity of 12 plant extracts is here described for the first time and polyphenols and triterpenes were identified as the probable bioactive constituents of T. phaeocarpa and M. ilicifolia, respectively.

Asunto(s)

Neuroblastoma , Triterpenos , Infección por el Virus Zika , Virus Zika , Animales , Niño , Chlorocebus aethiops , Humanos , Neuroblastoma/tratamiento farmacológico , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Polifenoles/farmacología , Espectrometría de Masas en Tándem , Triterpenos/farmacología , Células Vero , Infección por el Virus Zika/tratamiento farmacológico

RESUMEN

Cancer chemotherapy and radiotherapy may result in mucositis characterized by stem cell damage and inflammation in the gastrointestinal tract. The molecular mechanisms underlying this pathology remain unknown. Based on the assumption that mitochondrial CPG-DNA (mtDNA) released and sensed by TLR9 could underlie mucositis pathology, we analyzed the mtDNA levels in sera as well as inflammatory and disease parameters in the small intestine from wild-type (WT) and TLR9-deficient mice (TLR9-/-) in an experimental model of intestinal mucositis induced by irinotecan. Additionally, we verified the ability of WT and TLR9-/- macrophages to respond to CpG-DNA in vitro. WT mice injected with irinotecan presented a progressive increase in mtDNA in the serum along with increased hematocrit, shortening of small intestine length, reduction of intestinal villus:crypt ratio and increased influx of neutrophils, which were followed by higher expression of Nlrp3 and Casp1 mRNA and increased IL-1ß levels in the ileum when compared to vehicle-injected mice. TLR9-deficient mice were protected in all these parameters when compared to WT mice. Furthermore, TLR9 was required for the production of IL-1ß and NO after macrophage stimulation with CpG-DNA. Overall, our findings show that the amount of circulating free CpG-DNA is increased upon chemotherapy and that TLR9 activation is important for NLRP3 inflammasome transcription and further IL-1ß release, playing a central role in the development of irinotecan-induced intestinal mucositis. We suggest that TLR9 antagonism may be a new therapeutic strategy for limiting irinotecan-induced intestinal inflammation.

Asunto(s)

Mucositis , Animales , ADN Mitocondrial/genética , Inflamación/metabolismo , Irinotecán/toxicidad , Ligandos , Ratones , Ratones Noqueados , Mucositis/inducido químicamente , Mucositis/tratamiento farmacológico , Mucositis/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/metabolismo

RESUMEN

cis-Aconitic acid is a constituent from the leaves of Echinodorus grandiflorus, a medicinal plant traditionally used in Brazil to treat inflammatory conditions, including arthritic diseases. The present study aimed to investigate the anti-arthritic effect of cis-aconitic acid in murine models of antigen-induced arthritis and monosodium urate-induced gout. The possible underlying mechanisms of action was evaluated in THP-1 macrophages. Oral treatment with cis-aconitic acid (10, 30, and 90 mg/kg) reduced leukocyte accumulation in the joint cavity and C-X-C motif chemokine ligand 1 and IL-1ß levels in periarticular tissue. cis-Aconitic acid treatment reduced joint inflammation in tissue sections of antigen-induced arthritis mice and these effects were associated with decreased mechanical hypernociception. Administration of cis-aconitic acid (30 mg/kg p. o.) also reduced leukocyte accumulation in the joint cavity after the injection of monosodium urate crystals. cis-Aconitic acid reduced in vitro the release of TNF-α and phosphorylation of IκBα in lipopolysaccharide-stimulated THP-1 macrophages, suggesting that inhibition of nuclear factor kappa B activation was an underlying mechanism of cis-aconitic acid-induced anti-inflammatory effects. In conclusion, cis-aconitic acid has significant anti-inflammatory effects in antigen-induced arthritis and monosodium urate-induced arthritis in mice, suggesting its potential for the treatment of inflammatory diseases of the joint in humans. Additionally, our findings suggest that this compound may contribute to the anti-inflammatory effect previously reported for E. grandiflorus extracts.

Asunto(s)

Alismataceae , Gota , Humanos , Ratones , Animales , Ácido Aconítico/farmacología , Inhibidor NF-kappaB alfa , Ácido Úrico , Lipopolisacáridos , FN-kappa B , Factor de Necrosis Tumoral alfa , Ligandos , Alismataceae/química , Gota/inducido químicamente , Gota/tratamiento farmacológico , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Quimiocinas , Inflamación

RESUMEN

Mucositis is a major clinical complication associated with cancer treatment and may limit the benefit of chemotherapy. Leukocytes and inflammatory mediators have been extensively associated with mucositis severity. However, the role of eosinophils in the pathophysiology of chemotherapy-induced mucositis remains to be elucidated. Here, using GATA-1-deficient mice, we investigated the role of eosinophils in intestinal mucositis. There was marked accumulation of eosinophils in mice given irinotecan and eosinophil ablation inhibited intestinal mucositis. Treatment with Evasin-4, a chemokine receptor antagonist, reduced the recruitment of eosinophils and decreased irinotecan-induced mucositis. Importantly, Evasin-4 did not interfere negatively with the antitumour effects of irinotecan. Evasin-4 was of benefit for mice given high doses of irinotecan once Evasin-4-treated mice presented delayed mortality. Altogether, our findings suggest that Evasin-4 may have significant mucosal-protective effects in the context of antineoplastic chemotherapy and may, therefore, be useful in combination with anticancer treatment in cancer patients.

Asunto(s)

Antineoplásicos , Mucositis , Animales , Antineoplásicos/uso terapéutico , Camptotecina/efectos adversos , Eosinófilos/patología , Humanos , Mucosa Intestinal/patología , Irinotecán/efectos adversos , Ratones , Mucositis/inducido químicamente , Mucositis/tratamiento farmacológico , Mucositis/patología

RESUMEN

Paracoccidioidomycosis (PCM) is a systemic disease caused by Paracoccidioides spp. PCM is endemic in Latin America and most cases are registered in Brazil. This mycosis affects mainly the lungs, but can also spread to other tissues and organs, including the liver. Several approaches have been investigated to improve treatment effectiveness and protection against the disease. Extracellular vesicles (EVs) are good antigen delivery vehicles. The present work aims to investigate the use of EVs derived from Paracoccidioides brasiliensis as an immunization tool in a murine model of PCM. For this, male C57BL/6 were immunized with two doses of EVs plus adjuvant and then infected with P. brasiliensis. EV immunization induced IgM and IgG in vivo and cytokine production by splenocytes ex vivo. Further, immunization with EVs had a positive effect on mice infected with P. brasiliensis, as it induced activated T lymphocytes and NKT cell mobilization to the infected lungs, improved production of proinflammatory cytokines and the histopathological profile, and reduced fungal burden. Therefore, the present study shows a new role for P. brasiliensis EVs in the presence of adjuvant as modulators of the host immune system, suggesting their utility as immunizing agents.

Asunto(s)

Antígenos Fúngicos/inmunología , Vesículas Extracelulares/microbiología , Paracoccidioides/inmunología , Paracoccidioidomicosis/inmunología , Paracoccidioidomicosis/microbiología , Sustancias Protectoras/farmacología , Animales , Anticuerpos Antifúngicos/inmunología , Movimiento Celular , Citocinas/metabolismo , Vesículas Extracelulares/efectos de los fármacos , Inmunización , Memoria Inmunológica , Pulmón/microbiología , Pulmón/patología , Activación de Linfocitos/inmunología , Masculino , Ratones Endogámicos C57BL , Células T Asesinas Naturales/inmunología , Estándares de Referencia

RESUMEN

St. Louis encephalitis virus (SLEV) is a neglected mosquito-borne flavivirus that causes severe neurological disease in humans. SLEV replication in the central nervous system (CNS) induces the local production of interferons (IFNs), which are attributed to host protection. The antiviral response to SLEV infection in the CNS is not completely understood, which led us to characterize the roles of IFNs using mouse models of St. Louis encephalitis. We infected mice deficient in type I IFN receptor (ABR-/-) or deficient in Type II IFN (IFNγ-/-) and assessed the contribution of each pathway to disease development. We found that type I and II IFNs play different roles in SLEV infection. Deficiency in type I IFN signaling was associated to an early and increased mortality, uncontrolled SLEV replication and impaired ISG expression, leading to increased proinflammatory cytokine production and brain pathology. Conversely, IFNγ-/- mice were moderately resistant to SLEV infection. IFNγ deficiency caused no changes to viral load or SLEV-induced encephalitis and did not change the expression of ISGs in the brain. We found that type I IFN is essential for the control of SLEV replication whereas type II IFN was not associated with protection in this model.

Asunto(s)

Encéfalo/inmunología , Encéfalo/virología , Virus de la Encefalitis de San Luis/inmunología , Encefalitis de San Luis/inmunología , Interferón Tipo I/inmunología , Interferón gamma/inmunología , Animales , Encéfalo/patología , Modelos Animales de Enfermedad , Interferón Tipo I/genética , Interferón gamma/genética , Ratones , Ratones Endogámicos C57BL , Carga Viral , Replicación Viral/inmunología

RESUMEN

Although dysbiosis in the gut microbiota is known to be involved in several inflammatory diseases, whether any specific bacterial taxa control host response to inflammatory stimuli is still elusive. Here, we hypothesized that dysbiotic indigenous taxa could be involved in modulating host response to inflammatory triggers. To test this hypothesis, we conducted experiments in germ-free (GF) mice and in mice colonized with dysbiotic taxa identified in conventional (CV) mice subjected to chemotherapy-induced mucositis. First, we report that the absence of microbiota decreased inflammation and damage in the small intestine after administration of the chemotherapeutic agent 5-fluorouracil (5-FU). Also, 5-FU induced a shift in CV microbiota resulting in higher amounts of Enterobacteriaceae, including E. coli, in feces and small intestine and tissue damage. Prevention of Enterobacteriaceae outgrowth by treating mice with ciprofloxacin resulted in diminished 5-FU-induced tissue damage, indicating that this bacterial group is necessary for 5-FU-induced inflammatory response. In addition, monocolonization of germ-free (GF) mice with E. coli led to reversal of the protective phenotype during 5-FU chemotherapy. E. coli monocolonization decreased the basal plasma corticosterone levels and blockade of glucocorticoid receptor in GF mice restored inflammation upon 5-FU treatment. In contrast, treatment of CV mice with ciprofloxacin, that presented reduction of Enterobacteriaceae and E. coli content, induced an increase in corticosterone levels. Altogether, these findings demonstrate that Enterobacteriaceae outgrowth during dysbiosis impacts inflammation and tissue injury in the small intestine. Importantly, indigenous Enterobacteriaceae modulates host production of the anti-inflammatory steroid corticosterone and, consequently, controls inflammatory responsiveness in mice.

Asunto(s)

Corticosterona/metabolismo , Disbiosis/microbiología , Enterobacteriaceae/crecimiento & desarrollo , Animales , Antineoplásicos/efectos adversos , Bacterias/clasificación , Bacterias/genética , Bacterias/crecimiento & desarrollo , Bacterias/aislamiento & purificación , Corticosterona/inmunología , Disbiosis/etiología , Disbiosis/inmunología , Disbiosis/metabolismo , Enterobacteriaceae/genética , Fluorouracilo/efectos adversos , Microbioma Gastrointestinal/efectos de los fármacos , Humanos , Intestino Delgado/inmunología , Intestino Delgado/metabolismo , Intestino Delgado/microbiología , Masculino , Ratones

RESUMEN

This study investigates the participation of PI3Kγ in the development of joint inflammation and dysfunction in an experimental model of acute gout in mice. Acute gout was induced by injection of monosodium urate (MSU) crystals into the tibiofemoral joint of mice. The involvement of PI3Kγ was evaluated using a selective inhibitor and mice deficient for PI3Kγ (PI3Kγ-/- ) or with loss of kinase activity. Neutrophils recovered from the inflamed joint were quantified and stained for phosphorylated Akt (pAkt) and production of reactive oxygen species (ROS). The adherence of leukocytes to the joint microvasculature was assessed by intravital microscopy and cleaved caspase-1 by Western blot. Injection of MSU crystals induced massive accumulation of neutrophils expressing phosphorylated Akt. In the absence of PI3Kγ, there was reduction of pAkt expression, chemokine production, and neutrophil recruitment. Genetic or pharmacological inhibition of PI3Kγ reduced the adherence of leukocytes to the joint microvasculature, even in joints with established inflammation. Neutrophils from PI3Kγ-/- mice produced less ROS than wild-type neutrophils. There was decreased joint damage and dysfunction in the absence of PI3Kγ. In addition, in the absence of PI3Kγ activity, there was reduction of cleaved caspase-1 and IL-1ß production in synovial tissue after injection of MSU crystals and leukotriene B4 . Our studies suggest that PI3Kγ is crucial for MSU crystal-induced acute joint inflammation. It is necessary for regulating caspase-1 activation and for mediating neutrophil migration and activation. Drugs that impair PI3Kγ function may be useful to control acute gout inflammation.

Asunto(s)

Artritis Gotosa/enzimología , Artritis Gotosa/inmunología , Caspasa 1/metabolismo , Fosfatidilinositol 3-Quinasa Clase Ib/metabolismo , Infiltración Neutrófila , Enfermedad Aguda , Animales , Adhesión Celular , Movimiento Celular , Fosfatidilinositol 3-Quinasa Clase Ib/deficiencia , Citoplasma/metabolismo , Activación Enzimática , Inflamasomas/metabolismo , Inflamación/patología , Interleucina-1beta/metabolismo , Articulaciones/patología , Leucotrieno B4/metabolismo , Masculino , Ratones Endogámicos C57BL , Microvasos/patología , Neutrófilos/metabolismo , Nocicepción , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Membrana Sinovial/irrigación sanguínea , Ácido Úrico

RESUMEN

Aim: Characterize the course of acute Aspergillus fumigatus lung infection in immunocompetent mice, investigating the immunological, pathological and tissue functional modifications. Materials & methods: C57BL/6 mice were intranasally infected with A. fumigatus conidia and euthanized to access inflammatory parameters. Results: Mice infected with A. fumigatus showed an inoculum-dependent lethality and body weight loss. An intense proinflammatory cytokine release, neutrophil infiltrate and pulmonary dysfunction was also observed in the early phase of infection. In the late phase of infection, proresolving mediators release, apoptosis and efferocytosis increased and lung tissue architecture is restored. Conclusion: Our study characterized an immunocompetent model of acute pulmonary Aspergillus infection in mice and opened an array of possibilities for investigations on interactions of A. fumigatus with host-immune system.

Asunto(s)

Lesión Pulmonar Aguda/microbiología , Aspergillus fumigatus/patogenicidad , Citocinas/inmunología , Inmunocompetencia , Pulmón/microbiología , Lesión Pulmonar Aguda/inmunología , Animales , Apoptosis , Aspergillus fumigatus/inmunología , Modelos Animales de Enfermedad , Interacciones Huésped-Patógeno/inmunología , Inflamación , Pulmón/inmunología , Pulmón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Neutrófilos/inmunología

RESUMEN

Influenza A virus (IAV) infects millions of people annually and predisposes to secondary bacterial infections. Inhalation of fungi within the Cryptococcus complex causes pulmonary disease with secondary meningo-encephalitis. Underlying pulmonary disease is a strong risk factor for development of C. gattii cryptococcosis though the effect of concurrent infection with IAV has not been studied. We developed an in vivo model of Influenza A H1N1 and C. gattii co-infection. Co-infection resulted in a major increase in morbidity and mortality, with severe lung damage and a high brain fungal burden when mice were infected in the acute phase of influenza multiplication. Furthermore, IAV alters the host response to C. gattii, leading to recruitment of significantly more neutrophils and macrophages into the lungs. Moreover, IAV induced the production of type 1 interferons (IFN-α4/ß) and the levels of IFN-γ were significantly reduced, which can be associated with impairment of the immune response to Cryptococcus during co-infection. Phagocytosis, killing of cryptococci and production of reactive oxygen species (ROS) by IAV-infected macrophages were reduced, independent of previous IFN-γ stimulation, leading to increased proliferation of the fungus within macrophages. In conclusion, IAV infection is a predisposing factor for severe disease and adverse outcomes in mice co-infected with C. gattii.

Asunto(s)

Causalidad , Coinfección , Criptococosis/complicaciones , Cryptococcus gattii/patogenicidad , Subtipo H1N1 del Virus de la Influenza A/patogenicidad , Infecciones por Orthomyxoviridae/complicaciones , Acetilglucosaminidasa/metabolismo , Animales , Conducta Animal , Encéfalo/microbiología , Encéfalo/patología , Proliferación Celular , Quimiocinas/metabolismo , Coinfección/inmunología , Coinfección/microbiología , Coinfección/mortalidad , Coinfección/virología , Criptococosis/inmunología , Cryptococcus gattii/inmunología , Cryptococcus neoformans/inmunología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Perros , Femenino , Humanos , Subtipo H1N1 del Virus de la Influenza A/inmunología , Interferón gamma/metabolismo , Pulmón/enzimología , Pulmón/patología , Pulmón/virología , Macrófagos/metabolismo , Macrófagos/virología , Células de Riñón Canino Madin Darby , Ratones , Ratones Endogámicos C57BL , Neutrófilos , Óxido Nítrico/metabolismo , Infecciones por Orthomyxoviridae/inmunología , Peroxidasa/metabolismo , Ácido Peroxinitroso/metabolismo , Fagocitosis , Especies Reactivas de Oxígeno/metabolismo , Tasa de Supervivencia

RESUMEN

AIM: Leukotrienes (LTs) are pro-inflammatory lipid mediators formed by the enzyme 5-lipoxygenase (5-LO). The involvement of 5-LO metabolites in periodontal disease (PD) is not well defined. This study aimed to assess the role of 5-LO in experimental PD induced by Aggregatibacter actinomycetemcomitans (Aa). MATERIAL AND METHODS: In vivo experiments were carried out using SV129 wild-type (WT) and 5-LO-deficient (5lo-/- ) mice inoculated with Aa. Osteoclasts were stimulated in vitro with AaLPS in the presence or not of selective inhibitors of the 5-LO pathway, or LTB4 or platelet-activating factor (PAF), as PAF has already been shown to increase osteoclast activity. RESULTS: In 5lo-/- mice, there were no loss of alveolar bone and less TRAP-positive osteoclasts in periodontal tissues, after Aa inoculation, despite local production of TNF-α and IL-6. The differentiation and activity of osteoclasts stimulated with AaLPS were diminished in the presence of BLT1 antagonist or 5-LO inhibitor, but not in the presence of cysteinyl leukotriene receptor antagonist. The osteoclast differentiation induced by PAF was impaired by the BLT1 antagonism. CONCLUSION: In conclusion, LTB4 but not CysLTs is important for Aa-induced alveolar bone loss. Overall, LTB4 affects osteoclast differentiation and activity and is a key intermediate of PAF-induced osteoclastogenesis.

Asunto(s)

Aggregatibacter actinomycetemcomitans/patogenicidad , Pérdida de Hueso Alveolar/enzimología , Pérdida de Hueso Alveolar/microbiología , Araquidonato 5-Lipooxigenasa/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Hidroxiurea/análogos & derivados , Hidroxiurea/farmacología , Interleucina-6/metabolismo , Ratones , Osteoclastos/efectos de los fármacos , Reacción en Cadena en Tiempo Real de la Polimerasa , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

BACKGROUND: Dengue is the most prevalent arthropod-borne viral disease in the world. In this article we present results on the development, characterization and immunogenic evaluation of an alternative vaccine candidate against Dengue. METHODS: The MWNT-DENV3E nanoconjugate was developed by covalent functionalization of carboxylated multi-walled carbon nanotubes (MWNT) with recombinant dengue envelope (DENV3E) proteins. The recombinant antigens were bound to the MWNT using a diimide-activated amidation process and the immunogen was characterized by TEM, AFM and Raman Spectroscopy. Furthermore, the immunogenicity of this vaccine candidate was evaluated in a murine model. RESULTS: Immunization with MWNT-DENV3E induced comparable IgG responses in relation to the immunization with non-conjugated proteins; however, the inoculation of the nanoconjugate into mice generated higher titers of neutralizing antibodies. Cell-mediated responses were also evaluated, and higher dengue-specific splenocyte proliferation was observed in cell cultures derived from mice immunized with MWNT-DENV3E when compared to animals immunized with the non-conjugated DENV3E. CONCLUSIONS: Despite the recent licensure of the CYD-TDV dengue vaccine in some countries, results from the vaccine's phase III trial have cast doubts about its overall efficacy and global applicability. While questions about the effectiveness of the CYD-TDV vaccine still lingers, it is wise to keep at hand an array of vaccine candidates, including alternative non-classical approaches like the one presented here.

Asunto(s)

Formación de Anticuerpos , Vacunas contra el Dengue/inmunología , Dengue/prevención & control , Nanotubos de Carbono/química , Proteínas del Envoltorio Viral/inmunología , Animales , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Antígenos Virales/inmunología , Proliferación Celular , Citocinas/inmunología , Dengue/inmunología , Vacunas contra el Dengue/uso terapéutico , Virus del Dengue/inmunología , Femenino , Inmunidad Celular , Inmunoglobulina G/sangre , Ratones , Ratones Endogámicos BALB C , Microscopía de Fuerza Atómica , Microscopía Electrónica de Transmisión , Nanoconjugados/química , Nanomedicina , Proteínas Recombinantes/química , Proteínas Recombinantes/inmunología , Espectrometría Raman , Bazo/citología , Vacunas de Subunidad/inmunología , Vacunas de Subunidad/uso terapéutico

RESUMEN

AIMS: To determine the role of reactive oxygen species (ROS) on sodium nitroprusside (SNP)-induced tolerance. Additionally, we evaluated the role of ROS on NF-κB activation and pro-inflammatory cytokines production during SNP-induced tolerance. MAIN METHODS: To induce in vitro tolerance, endothelium-intact or -denuded aortic rings isolated from male Balb-c mice were incubated for 15, 30, 45 or 60min with SNP (10nmol/L). KEY FINDINGS: Tolerance to SNP was observed after incubation of endothelium-denuded, but not endothelium-intact aortas for 60min with this inorganic nitrate. Pre-incubation of denuded rings with tiron (superoxide anion (O2-) scavenger), and the NADPH oxidase inhibitors apocynin and atorvastatin reversed SNP-induced tolerance. l-NAME (non-selective NOS inhibitor) and l-arginine (NOS substrate) also prevented SNP-induced tolerance. Similarly, ibuprofen (non-selective cyclooxygenase (COX) inhibitor), nimesulide (selective COX-2 inhibitor), AH6809 (prostaglandin PGF2α receptor antagonist) or SQ29584 [PGH2/thromboxane TXA2 receptor antagonist] reversed SNP-induced tolerance. Increased ROS generation was detected in tolerant arteries and both tiron and atorvastatin reversed this response. Tiron prevented tolerance-induced increase on O2- and hydrogen peroxide (H2O2) levels. The increase onp65/NF-κB expression and TNF-α production in tolerant arteries was prevented by tiron. The major new finding of our study is that SNP-induced tolerance is mediated by NADPH-oxidase derived ROS and vasoconstrictor prostanoids derived from COX-2, which are capable of reducing the vasorelaxation induced by SNP. Additionally, we found that ROS mediate the activation of NF-κB and the production of TNF-α in tolerant arteries. SIGNIFICANCE: These findings identify putative molecular mechanisms whereby SNP induces tolerance in the vasculature.

Asunto(s)

Aorta/metabolismo , Ciclooxigenasa 2/metabolismo , Nitroprusiato/farmacología , Prostaglandina H2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Masculino , Ratones , Ratones Endogámicos BALB C , Vasodilatación/efectos de los fármacos

RESUMEN

Periodontal disease (PD) is a chronic inflammatory and alveolar bone destructive disease triggered by oral biofilm-producing microorganisms, such as Aggregatibacter actinomycetemcomitans. The levels of the phospholipid platelet-activating factor (PAF) in the saliva, gingival crevicular fluid, and periodontal tissues are significantly increased during inflammatory conditions, such as PD, but the exact mechanism that links PAF to alveolar bone resorption is not well understood. In the current study, alveolar bone resorption was induced by experimental PD through the oral inoculation of A. actinomycetemcomitans in wild-type (WT) and PAF receptor knockout (Pafr(-/-)) mice. In vitro experiments using A. actinomycetemcomitans lipopolysaccharide (LPS)-stimulated RAW 264.7 cells treated with a PAF receptor antagonist (UK74505) were also performed. The expression of lyso-PAF acetyltransferase in periodontal tissues was significantly increased 3 h after A. actinomycetemcomitans LPS injection in mice. WT and Pafr(-/-) mice that were subjected to oral inoculation of A. actinomycetemcomitans presented neutrophil accumulation and increased levels of CXCL-1 and tumor necrosis factor alpha (TNF-α) in periodontal tissues. However, Pafr(-/-) mice presented less alveolar bone loss than WT mice. The in vitro blockade of the PAF receptor impaired the resorptive activity of A. actinomycetemcomitans LPS-activated osteoclasts. In conclusion, this study shows for the first time that the blockade of PAF receptor may contribute to the progression of PD triggered by A. actinomycetemcomitans by directly affecting the differentiation and activity of osteoclasts.

Asunto(s)

Infecciones por Pasteurellaceae/patología , Pasteurellaceae/patogenicidad , Enfermedades Periodontales/patología , Glicoproteínas de Membrana Plaquetaria/antagonistas & inhibidores , Receptores Acoplados a Proteínas G/antagonistas & inhibidores , Pérdida de Hueso Alveolar/patología , Animales , Resorción Ósea , Línea Celular , Citocinas/metabolismo , Modelos Animales de Enfermedad , Endotoxinas/inmunología , Encía/inmunología , Encía/patología , Lipopolisacáridos/inmunología , Macrófagos/inmunología , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neutrófilos/inmunología , Osteoclastos/metabolismo , Infecciones por Pasteurellaceae/microbiología , Enfermedades Periodontales/microbiología , Glicoproteínas de Membrana Plaquetaria/deficiencia , Receptores Acoplados a Proteínas G/deficiencia

RESUMEN

OBJECTIVE: Deposition of monosodium urate monohydrate (MSU) crystals in the joints promotes an intense inflammatory response and joint dysfunction. This study evaluated the role of the NLRP3 inflammasome and 5-lipoxygenase (5-LOX)-derived leukotriene B(4) (LTB(4) ) in driving tissue inflammation and hypernociception in a murine model of gout. METHODS: Gout was induced by injecting MSU crystals into the joints of mice. Wild-type mice and mice deficient in NLRP3, ASC, caspase 1, interleukin-1ß (IL-1ß), IL-1 receptor type I (IL-1RI), IL-18R, myeloid differentiation factor 88 (MyD88), or 5-LOX were used. Evaluations were performed to assess neutrophil influx, LTB(4) activity, cytokine (IL-1ß, CXCL1) production (by enzyme-linked immunosorbent assay), synovial microvasculature cell adhesion (by intravital microscopy), and hypernociception. Cleaved caspase 1 and production of reactive oxygen species (ROS) were analyzed in macrophages by Western blotting and fluorometric assay, respectively. RESULTS: Injection of MSU crystals into the knee joints of mice induced neutrophil influx and neutrophil-dependent hypernociception. MSU crystal-induced neutrophil influx was CXCR2-dependent and relied on the induction of CXCL1 in an NLRP3/ASC/caspase 1/IL-1ß/MyD88-dependent manner. LTB(4) was produced rapidly after injection of MSU crystals, and this was necessary for caspase 1-dependent IL-1ß production and consequent release of CXCR2-acting chemokines in vivo. In vitro, macrophages produced LTB(4) after MSU crystal injection, and LTB(4) was relevant in the MSU crystal-induced maturation of IL-1ß. Mechanistically, LTB(4) drove MSU crystal-induced production of ROS and ROS-dependent activation of the NLRP3 inflammasome. CONCLUSION: These results reveal the role of the NLRP3 inflammasome in mediating MSU crystal-induced inflammation and dysfunction of the joints, and highlight a previously unrecognized role of LTB(4) in driving NLRP3 inflammasome activation in response to MSU crystals, both in vitro and in vivo.

Asunto(s)

Proteínas Portadoras/metabolismo , Gota/metabolismo , Hiperalgesia/metabolismo , Inflamasomas/metabolismo , Leucotrieno B4/metabolismo , Infiltración Neutrófila/fisiología , Neutrófilos/metabolismo , Animales , Caspasa 1/metabolismo , Citocinas/metabolismo , Gota/inducido químicamente , Gota/inmunología , Hiperalgesia/inmunología , Inflamasomas/inmunología , Inflamación/inmunología , Inflamación/metabolismo , Interleucina-1beta/metabolismo , Leucotrieno B4/inmunología , Macrófagos/inmunología , Macrófagos/metabolismo , Masculino , Ratones , Ratones Noqueados , Proteína con Dominio Pirina 3 de la Familia NLR , Neutrófilos/inmunología , Especies Reactivas de Oxígeno/metabolismo , Membrana Sinovial/inmunología , Membrana Sinovial/metabolismo , Ácido Úrico/farmacología