RESUMO
Group A Streptococcus (GAS) commonly causes pharyngitis and skin infections. Little is known why streptococcal pharyngitis usually does not lead to pneumonia and why the skin is a favorite niche for GAS. To partially address these questions, the effectiveness of neutrophils in clearing wild-type (wt) M1T1 GAS strain MGAS2221 from the lung and from the skin was examined in murine models of intratracheal pneumonia and subcutaneous infection. Ninety-nine point seven percent of the MGAS2221 inoculum was cleared from the lungs of C57BL/6J mice at 24 h after inoculation, while there was no MGAS2221 clearance from skin infection sites. The bronchial termini had robust neutrophil infiltration, and depletion of neutrophils abolished MGAS2221 clearance from the lung. Phagocyte NADPH oxidase but not myeloperoxidase was required for MGAS2221 clearance. Thus, wt M1T1 GAS can be cleared by neutrophils using an NADPH oxidase-dependent mechanism in the lung. MGAS2221 induced robust neutrophil infiltration at the edge of skin infection sites and throughout infection sites at 24 h and 48 h after inoculation, respectively. Neutrophils within MGAS2221 infection sites had no nuclear staining. Skin infection sites of streptolysin S-deficient MGAS2221 ΔsagA were full of neutrophils with nuclear staining, whereas MGAS2221 ΔsagA infection was not cleared. Gp91phox knockout (KO) and control mice had similar GAS numbers at skin infection sites and similar abilities to select SpeB activity-negative (SpeBA-) variants. These results indicate that phagocyte NADPH oxidase-mediated GAS killing is compromised in the skin. Our findings support a model for GAS skin tropism in which GAS generates an anoxic niche to evade phagocyte NADPH oxidase-mediated clearance.
Assuntos
Interações Hospedeiro-Patógeno/imunologia , Pulmão/enzimologia , NADPH Oxidases/imunologia , Neutrófilos/enzimologia , Infecções Estreptocócicas/enzimologia , Streptococcus pyogenes/patogenicidade , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Feminino , Pulmão/imunologia , Pulmão/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NADPH Oxidases/genética , Infiltração de Neutrófilos , Neutrófilos/imunologia , Neutrófilos/microbiologia , Especificidade de Órgãos , Fagócitos/enzimologia , Fagócitos/imunologia , Pele/imunologia , Pele/microbiologia , Infecções Estreptocócicas/imunologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/imunologia , Estreptolisinas/deficiência , Estreptolisinas/genética , Estreptolisinas/imunologiaRESUMO
Coxiella burnetii is an intracellular pathogen and the cause of Q fever. Gamma interferon (IFN-γ) is critical for host protection from infection, but a role for type I IFN in C. burnetii infection has not been determined. Type I IFN supports host protection from a related pathogen, Legionella pneumophila, and we hypothesized that it would be similarly protective in C. burnetii infection. In contrast to our prediction, IFN-α receptor-deficient (IFNAR(-/-)) mice were protected from C. burnetii-induced infection. Therefore, the role of type I IFN in C. burnetii infection was distinct from that in L. pneumophila Mice treated with a double-stranded-RNA mimetic were protected from C. burnetii-induced weight loss through an IFNAR-independent pathway. We next treated mice with recombinant IFN-α (rIFN-α). When rIFN-α was injected by the intraperitoneal route during infection, disease-induced weight loss was exacerbated. Mice that received rIFN-α by this route had dampened interleukin 1ß (IL-1ß) expression in bronchoalveolar lavage fluids. However, when rIFN-α was delivered to the lung, bacterial replication was decreased in all tissues. Thus, the presence of type I IFN in the lung protected from infection, but when delivered to the periphery, type I IFN enhanced disease, potentially by dampening inflammatory cytokines. To better characterize the capacity for type I IFN induction by C. burnetii, we assessed expression of IFN-ß transcripts by human macrophages following stimulation with lipopolysaccharide (LPS) from C. burnetii Understanding innate responses in C. burnetii infection will support the discovery of novel therapies that may be alternative or complementary to the current antibiotic treatment.
Assuntos
Coxiella burnetii/imunologia , Interações Hospedeiro-Patógeno , Interferon-alfa/imunologia , Febre Q/imunologia , Receptor de Interferon alfa e beta/imunologia , Animais , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/imunologia , Líquido da Lavagem Broncoalveolar/imunologia , Líquido da Lavagem Broncoalveolar/microbiologia , Coxiella burnetii/efeitos dos fármacos , Coxiella burnetii/genética , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Imunidade Inata , Injeções Intraperitoneais , Interferon-alfa/genética , Interferon-alfa/farmacologia , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Legionella pneumophila/genética , Legionella pneumophila/imunologia , Lipopolissacarídeos , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/microbiologia , Camundongos , Camundongos Knockout , Febre Q/tratamento farmacológico , Febre Q/microbiologia , Febre Q/patologia , Receptor de Interferon alfa e beta/antagonistas & inibidores , Receptor de Interferon alfa e beta/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/farmacologia , Transdução de Sinais , Redução de Peso/efeitos dos fármacosRESUMO
Coxiella burnetii, the causative agent of Q fever, is an obligate intracellular, primarily pulmonary, bacterial pathogen. Although much is known about adaptive immune responses against this bacterium, our understanding of innate immune responses against C. burnetii is not well defined, particularly within the target tissue for infection, the lung. Previous studies examined the roles of the innate immune system receptors Toll-like receptor 2 (TLR2) and TLR4 in peripheral infection models and described minimal phenotypes in specific gene deletion animals compared to those of their wild-type controls (S. Meghari et al., Ann N Y Acad Sci 1063:161-166, 2005,http://dx.doi.org/10.1196/annals.1355.025; A. Honstettre et al., J Immunol 172:3695-3703, 2004,http://dx.doi.org/10.4049/jimmunol.172.6.3695) . Here, we assessed the roles for TLR2, TLR4, and MyD88 in pulmonary C. burnetii infection and compared responses to those that occurred in TLR2- and TLR4-deficient animals following peripheral infection. As observed previously, neither TLR2 nor TLR4 was needed for limiting bacterial growth after peripheral infection. In contrast, TLR2 and, to a lesser extent, TLR4 limited growth (or dissemination) of the bacterium in the lung and spleen after pulmonary infection. TLR2, TLR4, and MyD88 were not required for the general inflammatory response in the lungs after pulmonary infection. However, MyD88 signaling was important for infection-induced morbidity. Finally, TLR2 expression on hematopoietic cells was most important for limiting bacterial growth in the lung. These results expand on our knowledge of the roles for TLR2 and TLR4 in C. burnetii infection and suggest various roles for these receptors that are dictated by the site of infection.
Assuntos
Coxiella burnetii/fisiologia , Pneumopatias/microbiologia , Fator 88 de Diferenciação Mieloide/metabolismo , Febre Q/metabolismo , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Quimera , Regulação da Expressão Gênica/imunologia , Regulação da Expressão Gênica/fisiologia , Pneumopatias/metabolismo , Camundongos , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Peritonite/microbiologia , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genéticaRESUMO
Epilobium angustifolium is a medicinal plant used around the world in traditional medicine for the treatment of many disorders and ailments. Experimental studies have demonstrated that Epilobium extracts possess a broad range of pharmacological and therapeutic effects, including antioxidant, anti-proliferative, anti-inflammatory, antibacterial, and anti-aging properties. Flavonoids and ellagitannins, such as oenothein B, are among the compounds considered to be the primary biologically active components in Epilobium extracts. In this review, we focus on the biological properties and the potential clinical usefulness of oenothein B, flavonoids, and other polyphenols derived from E. angustifolium. Understanding the biochemical properties and therapeutic effects of polyphenols present in E. angustifolium extracts will benefit further development of therapeutic treatments from this plant. Copyright © 2016 John Wiley & Sons, Ltd.
Assuntos
Epilobium/química , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Polifenóis/química , HumanosRESUMO
Solute carrier 11A1 (SLC11A1) is a divalent ion transporter formerly known as the natural resistance-associated macrophage protein (NRAMP1) and the Bcg/Lsh/Ity locus. SLC11A1 was thought to be exclusively expressed in monocyte/macrophages and to have roles in phagosome maturation and cell activation. We characterized the expression of SLC11A1 in the majority of human and bovine γδ T cells and NK cells and in human CD3(+)CD45RO(+) T cells. Consistent with a role for iron-dependent inhibition of protein tyrosine phosphatases, SLC11A1(+) lymphocytes were more prone to activation and retained tyrosine phosphorylation. Transfection of SLC11A1 into a human γδ T cell-like line rendered the cells more prone to activation. Nonadherent splenocytes from wild-type mice expressed significantly greater IFN-γ compared with cells from Sv/129 (SLC11A1(-/-)) mice. Our data suggest that SLC11A1 has a heretofore unknown role in activation of a large subset of innate lymphocytes that are critical sources of IFN-γ. SLC11A1(+) animals have enhanced innate IFN-γ expression in response to Salmonella infection compared with SLC11A1(-) mice, which include commonly used inbred laboratory mice. Expression of SLC11A1 in innate lymphocytes and its role in augmenting their activation may account for inconsistencies in studies of innate lymphocytes in different animal models.
Assuntos
Proteínas de Transporte de Cátions/biossíntese , Imunidade Inata , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Regulação para Cima/imunologia , Animais , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/fisiologia , Bovinos , Humanos , Imunidade Inata/genética , Ativação Linfocitária/genética , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , Fosforilação/genética , Fosforilação/imunologia , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Receptores de Antígenos de Linfócitos T gama-delta/biossíntese , Subpopulações de Linfócitos T/enzimologia , Tirosina/metabolismo , Regulação para Cima/genéticaRESUMO
Pulmonary Francisella tularensis and Burkholderia pseudomallei infections are highly lethal in untreated patients, and current antibiotic regimens are not always effective. Activating the innate immune system provides an alternative means of treating infection and can also complement antibiotic therapies. Several natural agonists were screened for their ability to enhance host resistance to infection, and polysaccharides derived from the Acai berry (Acai PS) were found to have potent abilities as an immunotherapeutic to treat F. tularensis and B. pseudomallei infections. In vitro, Acai PS impaired replication of Francisella in primary human macrophages co-cultured with autologous NK cells via augmentation of NK cell IFN-γ. Furthermore, Acai PS administered nasally before or after infection protected mice against type A F. tularensis aerosol challenge with survival rates up to 80%, and protection was still observed, albeit reduced, when mice were treated two days post-infection. Nasal Acai PS administration augmented intracellular expression of IFN-γ by NK cells in the lungs of F. tularensis-infected mice, and neutralization of IFN-γ ablated the protective effect of Acai PS. Likewise, nasal Acai PS treatment conferred protection against pulmonary infection with B. pseudomallei strain 1026b. Acai PS dramatically reduced the replication of B. pseudomallei in the lung and blocked bacterial dissemination to the spleen and liver. Nasal administration of Acai PS enhanced IFN-γ responses by NK and γδ T cells in the lungs, while neutralization of IFN-γ totally abrogated the protective effect of Acai PS against pulmonary B. pseudomallei infection. Collectively, these results demonstrate Acai PS is a potent innate immune agonist that can resolve F. tularensis and B. pseudomallei infections, suggesting this innate immune agonist has broad-spectrum activity against virulent intracellular pathogens.
Assuntos
Arecaceae/química , Imunidade Inata/efeitos dos fármacos , Melioidose/prevenção & controle , Pneumonia/tratamento farmacológico , Polissacarídeos/farmacologia , Tularemia/prevenção & controle , Administração Intranasal , Animais , Burkholderia pseudomallei/efeitos dos fármacos , Burkholderia pseudomallei/imunologia , Modelos Animais de Doenças , Feminino , Francisella tularensis/efeitos dos fármacos , Francisella tularensis/imunologia , Interferon gama/metabolismo , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Longevidade/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Melioidose/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Pneumonia/imunologia , Pneumonia/microbiologia , Polissacarídeos/administração & dosagem , Polissacarídeos/isolamento & purificação , Tularemia/imunologiaRESUMO
BACKGROUND: Extracts of leaves from Clerodendrum have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts. METHODS: Polysaccharides from the leaves of Clerodendrum splendens were extracted and fractionated by ion exchange and size-exclusion chromatography. Molecular weight determination, sugar analysis, degree of methyl esterification, and other chemical characterization of the fractions were performed. Immunomodulatory activity of the fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO), cytokine production, and mitogen-activated protein kinase (MAPK) phosphorylation. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice, and severity of EAE was monitored in mice treated with intraperitoneal (i.p.) injections of the most active polysaccharide fraction. Lymph nodes (LN) and spleen were harvested, and levels of cytokines in supernatants from LN cells and splenocytes challenged with myelin oligodendrocyte glycoprotein peptide were determined. RESULTS: Fractions containing type II arabinogalactan had potent immunomodulatory activity. Specifically, the high-molecular weight sub-fraction CSP-AU1 (average of 38.5 kDa) induced NO and cytokine [interleukin (IL)-1α, -1ß, -6, -10, tumor necrosis factor (TNF; designated previously as TNF-α), and granulocyte macrophage-colony stimulating factor (GM-CSF)] production by human peripheral blood mononuclear cells (PBMCs) and monocyte/macrophages. CSP-AU1-induced secretion of TNF was prevented by Toll-like receptor 4 (TLR4) antagonist LPS-RS, indicating a role for TLR4 signaling. Treatment with CSP-AU1 also induced phosphorylation of a number of MAPKs in human PBMC and activated AP-1/NF-κB. In vivo treatment of mice with CSP-AU1 and CSP-NU1 resulted in increased serum IL-6, IL-10, TNF, monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein (MIP)-1α/CCL3, and MIP-1ß/CCL4. CSP-AU1 treatment of mice with EAE (50 mg/kg, i.p., daily, 13 days) resulted in significantly reduced disease severity in this experimental model of multiple sclerosis. Levels of IL-13, TNF, interferon (IFN)-γ, IL-17, and GM-CSF were also significantly decreased, whereas transforming growth factor (TGF)-ß was increased in LN cells from CSP-AU1-treated EAE mice. CONCLUSIONS: Polysaccharide CSP-AU1 is a potent natural innate immunomodulator with a broad spectrum of agonist activity in vitro and immunosupressive properties after chronic administration in vivo.
Assuntos
Clerodendrum/química , Encefalomielite Autoimune Experimental/tratamento farmacológico , Fatores Imunológicos/administração & dosagem , Polissacarídeos/administração & dosagem , Animais , Quimiocina CCL2/genética , Quimiocina CCL2/imunologia , Citocinas/genética , Citocinas/imunologia , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Feminino , Humanos , Fatores Imunológicos/isolamento & purificação , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Polissacarídeos/isolamento & purificação , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologiaRESUMO
Stimulation of innate immunity can protect against infectious insult and could be used in combination with other therapies. Since antibiotic resistance is an increasing concern, strategies to reduce the dose or eliminate the need for these drugs are warranted. Lipo-CRX is a formulation in which the TLR4 agonist CRX-527 is incorporated into lipid membranes in liposomes. Lipo-CRX is less inflammatory than either CRX-527 or LPS, but retains unique capacity to enhance host defense responses. We compared lipo-CRX to other agonists in vitro using mammalian cells and in vivo in mice, and assessed indicators of innate immune responses and protection from bacterial infection. Lipo-CRX is similar to E. coli LPS in its capacity to activate bovine γδ T cells and to recruit neutrophils into mouse lungs, but with less reactivity in the LAL assay. However, lipo-CRX uniquely induced the production of systemic innate immune cytokines. In the mouse model of brucellosis, delivery of lipo-CRX to the lungs reduced the dissemination of B. abortus. While lipo-CRX or the antibiotic ampicillin alone did not alter B. abortus burdens in the lung, the combination had a synergistic beneficial effect. Our data suggest that stimulating the innate immune system with lipo-CRX, either alone or when combined with antibiotics, can enhance bacterial clearance in the mouse model of brucellosis.
Assuntos
Brucella abortus , Brucelose , Animais , Bovinos , Camundongos , Lipossomos , Receptor 4 Toll-Like , Lipopolissacarídeos/farmacologia , Escherichia coli , Imunidade Inata , MamíferosRESUMO
Bats are natural reservoirs for several zoonotic viruses, potentially due to an enhanced capacity to control viral infection. However, the mechanisms of antiviral responses in bats are poorly defined. Here we established a Jamaican fruit bat (JFB, Artibeus jamaicensis) intestinal organoid model of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Upon infection with SARS-CoV-2, increased viral RNA and subgenomic RNA was detected, but no infectious virus was released, indicating that JFB organoids support only limited viral replication but not viral reproduction. SARS-CoV-2 replication was associated with significantly increased gene expression of type I interferons and inflammatory cytokines. Interestingly, SARS-CoV-2 also caused enhanced formation and growth of JFB organoids. Proteomics revealed an increase in inflammatory signaling, cell turnover, cell repair, and SARS-CoV-2 infection pathways. Collectively, our findings suggest that primary JFB intestinal epithelial cells mount successful antiviral interferon responses and that SARS-CoV-2 infection in JFB cells induces protective regenerative pathways.
Assuntos
COVID-19 , Quirópteros , Interferon Tipo I , Vírus , Animais , SARS-CoV-2 , Jamaica , Antivirais , OrganoidesRESUMO
In efforts to identify novel small molecules with anti-inflammatory properties, we discovered a unique series of tetracyclic indenoquinoxaline derivatives that inhibited lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 activation. Compound IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) was found to be a potent, noncytotoxic inhibitor of pro-inflammatory cytokine [interleukin (IL)-1α, IL-1ß, IL-6, IL-10, tumor necrosis factor (TNF)-α, interferon-γ, and granulocyte-macrophage colony-stimulating factor] and nitric oxide production by human and murine monocyte/macrophages. Three additional potent inhibitors of cytokine production were identified through further screening of IQ-1 analogs. The sodium salt of IQ-1 inhibited LPS-induced TNF-α and IL-6 production in MonoMac-6 cells with IC(50) values of 0.25 and 0.61 µM, respectively. Screening of 131 protein kinases revealed that derivative IQ-3 [11H-indeno[1,2-b]quinoxalin-11-one-O-(2-furoyl)oxime]was a specific inhibitor of the c-Jun N-terminal kinase (JNK) family, with preference for JNK3. This compound, as well as IQ-1 and three additional oxime indenoquinoxalines, were found to be high-affinity JNK inhibitors with nanomolar binding affinity and ability to inhibit c-Jun phosphorylation. Furthermore, docking studies showed that hydrogen bonding interactions of the active indenoquinoxalines with Asn152, Gln155, and Met149 of JNK3 played an important role in enzyme binding activity. Finally, we showed that the sodium salt of IQ-1 had favorable pharmacokinetics and inhibited the ovalbumin-induced CD4(+) T-cell immune response in a murine delayed-type hypersensitivity model in vivo. We conclude that compounds with an indenoquinoxaline nucleus can serve as specific small-molecule modulators for mechanistic studies of JNKs as well as a potential leads for the development of anti-inflammatory drugs.
Assuntos
Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Oximas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Quinoxalinas/farmacologia , Animais , Western Blotting , Células Cultivadas , Citocinas/antagonistas & inibidores , Ensaio de Imunoadsorção Enzimática , Humanos , Ligação de Hidrogênio , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , Modelos Moleculares , Oximas/química , Fosforilação , Inibidores de Proteínas Quinases/química , Quinoxalinas/químicaRESUMO
Polymicrobial pneumonias occur frequently in cattle, swine, and sheep, resulting in major economic losses. Individual pathogens comprising these complex infections may be mild on their own but can instead exhibit synergism or increase host susceptibility. Two examples of such pathogens, Mycoplasma ovipneumoniae (M. ovipneumoniae) and influenza D viruses (IDVs), naturally infect domestic sheep. In sheep, the role of M. ovipneumoniae in chronic nonprogressive pneumonia is well-established, but the pathogenesis of IDV infection has not previously been studied. We utilized a specific-pathogen-free sheep flock to study the clinical response to IDV infection in naïve vs. M. ovipneumoniae-exposed lambs. Lambs were inoculated intranasally with M. ovipneumoniae or mock infection, followed after four weeks by infection with IDV. Pathogen shedding was tracked, and immunological responses were evaluated by measuring acute phase response and IDV-neutralizing antibody titers. While lamb health statuses remained subclinical, M. ovipneumoniae-exposed lambs had significantly elevated body temperatures during IDV infection compared to M. ovipneumoniae-naïve, IDV-infected lambs. Moreover, we found a positive correlation between prior M. ovipneumoniae burden, early-infection IDV shedding, and IDV-neutralizing antibody response. Our findings suggest that IDV infection may not induce clinical symptoms in domestic sheep, but previous M. ovipneumoniae exposure may promote mild IDV-associated inflammation.
Assuntos
Doenças Transmissíveis , Mycoplasma ovipneumoniae , Infecções por Orthomyxoviridae , Orthomyxoviridae , Pneumonia , Doenças dos Ovinos , Thogotovirus , Animais , Anticorpos Neutralizantes , Bovinos , Infecções por Orthomyxoviridae/veterinária , Ovinos , SuínosRESUMO
Mycoplasma ovipneumoniae (M. ovipneumoniae) is a respiratory pathogen associated with mild to moderate respiratory disease in domestic lambs and severe pneumonia outbreaks in wild ruminants such as bighorn sheep. However, whether M. ovipneumoniae by itself causes clinical respiratory disease in domestic sheep in the absence of secondary bacterial pathogens is still unclear. The goal of our study was to better understand the role of M. ovipneumoniae as a respiratory pathogen in domestic sheep and to explore potential antibiotic treatment approaches. Therefore, we inoculated four 4-month-old, specific-pathogen-free lambs with fresh nasal wash fluids from M. ovipneumoniae-infected sheep. The lambs were monitored for M. ovipneumoniae colonization, M. ovipneumoniae-specific antibodies, clinical signs, and cellular and molecular correlates of lung inflammation for eight weeks. All lambs then were treated with gamithromycin and observed for an additional four weeks. M. ovipneumoniae inoculation resulted in stable colonization of the upper respiratory tract in all M. ovipneumoniae-inoculated, but in none of the four mock-infected control lambs. All M. ovipneumoniae-infected lambs developed a robust antibody response to M. ovipneumoniae within 2 weeks. However, we did not observe significant signs of respiratory disease, evidence of lung damage or inflammation in any of the infected lambs. Interestingly, treatment with gamithromycin, which blocked growth of the M. ovipneumoniae in vitro, failed to reduce M. ovipneumoniae colonization. These observations indicate that, in the absence of co-infections, M. ovipneumoniae caused asymptomatic colonization of the upper respiratory tract that was resistant to clearance by the host immune response and by gamithromycin treatment.
Assuntos
Mycoplasma ovipneumoniae , Doenças dos Ovinos , Carneiro da Montanha , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Assintomáticas , Ovinos , Doenças dos Ovinos/epidemiologiaRESUMO
Angiotensin Converting Enzyme 2 (ACE2) is the primary cell entry receptor for SARS-CoV and SARS-CoV-2 viruses. A disintegrin and metalloproteinase 17 (ADAM17) is a protease that cleaves ectodomains of transmembrane proteins, including that of ACE2 and the proinflammatory cytokine TNF-α, from cell surfaces upon cellular activation. We hypothesized that blockade of ADAM17 activity would alter COVID-19 pathogenesis. To assess this pathway, we blocked the function of ADAM17 using the monoclonal antibody MEDI3622 in the K18-hACE2 transgenic mouse model of COVID-19. Antibody-treated mice were healthier, less moribund, and had significantly lower lung pathology than saline-treated mice. However, the viral burden in the lungs of MEDI3622-treated mice was significantly increased. Thus, ADAM17 appears to have a critical anti-viral role, but also may promote inflammatory damage. Since the inflammatory cascade is ultimately the reason for adverse outcomes in COVID-19 patients, there may be a therapeutic application for the MEDI3622 antibody.
Assuntos
Proteína ADAM17 , Anticorpos Neutralizantes , COVID-19 , SARS-CoV-2 , Proteína ADAM17/antagonistas & inibidores , Proteína ADAM17/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , COVID-19/imunologia , COVID-19/terapia , COVID-19/virologia , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Transgênicos , Peptidil Dipeptidase A/metabolismo , SARS-CoV-2/imunologia , Carga ViralRESUMO
Bats are natural reservoirs for several zoonotic viruses, potentially due to an enhanced capacity to control viral infection. However, the mechanisms of antiviral responses in bats are poorly defined. Here we established a Jamaican fruit bat (JFB) intestinal organoid model of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. JFB organoids were susceptible to SARS-CoV-2 infection, with increased viral RNA and subgenomic RNA detected in cell lysates and supernatants. Gene expression of type I interferons and inflammatory cytokines was induced in response to SARS-CoV-2 but not in response to TLR agonists. Interestingly, SARS-CoV-2 did not lead to cytopathic effects in JFB organoids but caused enhanced organoid growth. Proteomic analyses revealed an increase in inflammatory signaling, cell turnover, cell repair, and SARS-CoV-2 infection pathways. Collectively, our findings suggest that primary JFB intestinal epithelial cells can mount a successful antiviral interferon response and that SARS-CoV-2 infection in JFB cells induces protective regenerative pathways.
RESUMO
Background and Aims: Recent evidence suggests that the gut is an additional target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, whether SARS-CoV-2 spreads via gastrointestinal secretions remains unclear. To determine the prevalence of gastrointestinal SARS-CoV-2 infection in asymptomatic subjects, we analyzed gastrointestinal biopsy and liquid samples from endoscopy patients for the presence of SARS-CoV-2. Methods: We enrolled 100 endoscopic patients without known SARS-CoV-2 infection (cohort A) and 12 patients with a previous COVID-19 diagnosis (cohort B) in a cohort study performed at a regional hospital. Gastrointestinal biopsies and fluids were screened for SARS-CoV-2 by polymerase chain reaction (PCR), immunohistochemistry, and virus isolation assay, and the stability of SARS-CoV-2 in gastrointestinal liquids in vitro was analyzed. Results: SARS-CoV-2 ribonucleic acid was detected by PCR in the colonic tissue of 1/100 patients in cohort A. In cohort B, 3 colonic liquid samples tested positive for SARS-CoV-2 by PCR and viral nucleocapsid protein was detected in the epithelium of the respective biopsy samples. However, no infectious virions were recovered from any samples. In vitro exposure of SARS-CoV-2 to colonic liquid led to a 4-log-fold reduction of infectious SARS-CoV-2 within 1 hour (P ≤ .05). Conclusion: Overall, the persistent detection of SARS-CoV-2 in endoscopy samples after resolution of COVID-19 points to the gut as a long-term reservoir for SARS-CoV-2. Since no infectious virions were recovered and SARS-CoV-2 was rapidly inactivated in the presence of colon liquids, it is unlikely that performing endoscopic procedures is associated with a significant infection risk due to undiagnosed asymptomatic or persistent gastrointestinal SARS-CoV-2 infections.
RESUMO
N-Formyl peptide receptors (FPRs) are G protein-coupled receptors (GPCRs) involved in host defense and sensing cellular dysfunction. Thus, FPRs represent important therapeutic targets. In the present studies, we screened 32 ligands (agonists and antagonists) of unrelated GPCRs for their ability to induce intracellular Ca²+ mobilization in human neutrophils and HL-60 cells transfected with human FPR1, FPR2, or FPR3. Screening of these compounds demonstrated that antagonists of gastrin-releasing peptide/neuromedin B receptors (BB1/BB2) PD168368 [(S)-a-methyl-a-[[[(4-nitrophenyl)amino]carbonyl]amino]-N-[[1-(2-pyridinyl) cyclohexyl]methyl]-1H-indole-3-propanamide] and PD176252 [(S)-N-[[1-(5-methoxy-2-pyridinyl)cyclohexyl]methyl]-a-methyl-a-[[-(4-nitrophenyl)amino]carbonyl]amino-1H-indole-3-propanamide] were potent mixed FPR1/FPR2 agonists, with nanomolar EC50 values. Cholecystokinin-1 receptor agonist A-71623 [Boc-Trp-Lys(ε-N-2-methylphenylaminocarbonyl)-Asp-(N-methyl)-Phe-NH2] was also a mixed FPR1/FPR2 agonist, but with a micromolar EC50. Screening of 56 Trp- and Phe-based PD176252/PD168368 analogs and 41 related nonpeptide/nonpeptoid analogs revealed 22 additional FPR agonists. Most were potent mixed FPR1/FPR2/FPR3 agonists with nanomolar EC50 values for FPR2, making them among the most potent nonpeptide FPR2 agonists reported to date. In addition, these agonists were also potent chemoattractants for murine and human neutrophils and activated reactive oxygen species production in human neutrophils. Molecular modeling of the selected agonists using field point methods allowed us to modify our previously reported pharmacophore model for the FPR2 ligand binding site. This model suggests the existence of three hydrophobic/aromatic subpockets and several binding poses of FPR2 agonists in the transmembrane region of this receptor. These studies demonstrate that FPR agonists could include ligands of unrelated GPCR and that analysis of such compounds can enhance our understanding of pharmacological effects of these ligands.
Assuntos
Indóis/farmacologia , Piridinas/farmacologia , Receptores da Bombesina/antagonistas & inibidores , Receptores de Formil Peptídeo/agonistas , Receptores de Lipoxinas/agonistas , Animais , Peptídeo Liberador de Gastrina/antagonistas & inibidores , Peptídeo Liberador de Gastrina/fisiologia , Células HL-60 , Humanos , Indóis/química , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos/efeitos dos fármacos , Neutrófilos/fisiologia , Piridinas/química , Receptores da Bombesina/fisiologia , Receptores de Formil Peptídeo/fisiologia , Receptores de Lipoxinas/fisiologiaRESUMO
Epilobium angustifolium has been traditionally used to treat of a number of diseases; however, not much is known regarding its effect on innate immune cells. In this study, we report that extracts of E. angustifolium activated functional responses in neutrophils and monocyte/macrophages. Activity-guided fractionation, followed by mass spectroscopy and NMR analysis, resulted in the identification of oenothein B as the primary component responsible for phagocyte activation. Oenothein B, a dimeric hydrolysable tannin, dose-dependently induced a number of phagocyte functions in vitro, including intracellular Ca(2+) flux, production of reactive oxygen species, chemotaxis, NF-kappaB activation, and proinflammatory cytokine production. Furthermore, oenothein B was active in vivo, inducing keratinocyte chemoattractant production and neutrophil recruitment to the peritoneum after intraperitoneal administration. Biological activity required the full oenothein B structure, as substructures of oenothein B (pyrocatechol, gallic acid, pyrogallol, 3,4-dihydroxybenzoic acid) were all inactive. The ability of oenothein B to modulate phagocyte functions in vitro and in vivo suggests that this compound is responsible for at least part of the therapeutic properties of E. angustifolium extracts.
Assuntos
Taninos Hidrolisáveis/farmacologia , Fatores Imunológicos/farmacologia , Ativação de Macrófagos , Macrófagos/efeitos dos fármacos , NF-kappa B/imunologia , Animais , Cálcio/agonistas , Cálcio/imunologia , Cálcio/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Quimiotaxia/efeitos dos fármacos , Quimiotaxia/imunologia , Citocinas/efeitos dos fármacos , Citocinas/imunologia , Citocinas/metabolismo , Epilobium/química , Feminino , Humanos , Taninos Hidrolisáveis/isolamento & purificação , Fatores Imunológicos/isolamento & purificação , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/agonistas , NF-kappa B/metabolismo , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/agonistas , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
Information concerning the development of neutralizing antibodies and their duration will be critical to establishing herd immunity for COVID-19. We sought to evaluate SARS-CoV-2 spike protein receptor-binding domain (RBD)-specific antibodies, their duration, and capacity for SARS-CoV-2 neutralization in volunteers while the pandemic spread within our community starting in March 2020. Those participants with the highest starting titers had the longest-lasting response, up to 12 months post-diagnosis. SARS-CoV-2 neutralization capacity was correlated with anti-RBD antibody levels. The majority of our participants with confirmed COVID-19 diagnosis had very mild or asymptomatic infections. We also detected low and largely non-neutralizing anti-RBD IgG titers in a few participants with no known COVID-19 diagnosis. Finally, we found that antibody responses induced by vaccination were significantly higher than those induced by natural infection. Thus, our study suggests that vaccination is still critical even for those naturally infected or diagnosed with COVID-19.
RESUMO
Over 950,000 whole-genome sequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been determined for viruses isolated from around the world. These sequences are critical for understanding the spread and evolution of SARS-CoV-2. Using global phylogenomics, we show that mutations frequently occur in the C-terminal end of ORF7a. We isolate one of these mutant viruses from a patient sample and use viral challenge experiments to link this isolate (ORF7aΔ115) to a growth defect. ORF7a is implicated in immune modulation, and we show that the C-terminal truncation negates anti-immune activities of the protein, which results in elevated type I interferon response to the viral infection. Collectively, this work indicates that ORF7a mutations occur frequently, and that these changes affect viral mechanisms responsible for suppressing the immune response.
Assuntos
COVID-19/imunologia , COVID-19/virologia , Imunidade , SARS-CoV-2/genética , Proteínas Virais/genética , Proteínas Virais/imunologia , Animais , Chlorocebus aethiops , Genoma Viral , Células HEK293 , Humanos , Interferon Tipo I/imunologia , Mutação , Filogenia , SARS-CoV-2/patogenicidade , Células Vero , Proteínas Virais Reguladoras e Acessórias/genéticaRESUMO
The risk posed by Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) dictates that live-virus research is conducted in a biosafety level 3 (BSL3) facility. Working with SARS-CoV-2 at lower biosafety levels can expedite research yet requires the virus to be fully inactivated. In this study, we validated and compared two protocols for inactivating SARS-CoV-2: heat treatment and ultraviolet irradiation. The two methods were optimized to render the virus completely incapable of infection while limiting the destructive effects of inactivation. We observed that 15 min of incubation at 65 °C completely inactivates high titer viral stocks. Complete inactivation was also achieved with minimal amounts of UV power (70,000 µJ/cm2), which is 100-fold less power than comparable studies. Once validated, the two methods were then compared for viral RNA quantification, virion purification, and antibody detection assays. We observed that UV irradiation resulted in a 2-log reduction of detectable genomes compared to heat inactivation. Protein yield following virion enrichment was equivalent for all inactivation conditions, but the quality of resulting viral proteins and virions were differentially impacted depending on inactivation method and time. Here, we outline the strengths and weaknesses of each method so that investigators might choose the one which best meets their research goals.