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1.
Cell Prolif ; 53(1): e12721, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31782850

RESUMO

OBJECTIVES: Secondary bacterial pneumonia is common following influenza infection. However, it remains unclear about the underlying molecular mechanisms. MATERIALS AND METHODS: We established a mouse model of post-influenza S aureus pneumonia using conditional Shp2 knockout mice (LysMCre/+ :Shp2flox/flox ). The survival, bacterial clearance, pulmonary histology, phenotype of macrophages, and expression of type I interferons and chemokines were assessed between SHP2 deletion and control mice (Shp2flox/flox ). We infused additional KC and MIP-2 to examine the reconstitution of antibacterial immune response in LysMCre/+ :Shp2flox/flox mice. The effect of SHP2 on signal molecules including MAPKs (JNK, p38 and Erk1/2), NF-κB p65 and IRF3 was further detected. RESULTS: LysMCre/+ :Shp2flox/flox mice displayed impaired antibacterial immunity and high mortality compared with control mice in post-influenza S aureus pneumonia. The attenuated antibacterial ability was associated with the induction of type I interferon and suppression of chemo-attractants KC and MIP-2, which reduced the infiltration of neutrophils into the lung upon secondary bacterial invasion. In additional, Shp2 knockout mice displayed enhanced polarization to alternatively activated macrophages (M2 phenotype). Further in vitro analyses consistently demonstrated that SHP2-deficient macrophages were skewed towards an M2 phenotype and had a decreased antibacterial capacity. Moreover, SHP2 modulated the inflammatory response to secondary bacterial infection via interfering with NF-κB and IRF3 signalling in macrophages. CONCLUSIONS: Our findings reveal that the SHP2 expression enhances the host immune response and prompts bacterial clearance in post-influenza S aureus pneumonia.


Assuntos
Vírus da Influenza A/imunologia , Macrófagos/imunologia , Infecções por Orthomyxoviridae/imunologia , Pneumonia Estafilocócica/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/deficiência , Staphylococcus aureus/imunologia , Animais , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/imunologia , Macrófagos/patologia , Camundongos , Camundongos Transgênicos , NF-kappa B/genética , NF-kappa B/imunologia , Infecções por Orthomyxoviridae/complicações , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/patologia , Pneumonia Estafilocócica/etiologia , Pneumonia Estafilocócica/genética , Pneumonia Estafilocócica/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/imunologia
2.
J Cell Physiol ; 235(1): 563-572, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31318050

RESUMO

Sepsis is a severe clinical disease, which is resulted from the excessive host inflammation response to the infection. Growing evidence indicates that Staphylococcus aureus pneumonia is a significant cause of sepsis, which can lead to intestinal injury, inflammation, and apoptosis. Studies have shown that miR-182-5p can serve as a tumor oncogene or a tumor suppressive microRNA in various cancers, however, its biological role in sepsis is still uninvestigated. Here, we reported that miR-182-5p was obviously increased in S. aureus pneumonia mice models. Loss of miR-182-5p inhibited intestinal damage and intestinal apoptosis as indicated by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, we observed the lack of miR-182-5p altered the local inflammatory response to pneumonia in the intestine. Elevated tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were observed in intestinal tissue of pneumonia groups compared with the shams. Furthermore, miR-182-5p knockout (KO) pneumonia group demonstrated decreased levels of intestinal TNF-α and IL-6. Primary murine intestinal epithelial cells were isolated and cultured in our investigation. We exhibited downregulation of miR-182-5p repressed intestinal epithelial cells apoptosis and rescued the cell viability. Meanwhile, miR-182-5p caused elevated cell apoptosis and reduced cell proliferation. Moreover, the surfactant protein D (SP-D) binds with the bacterial pathogens and remove the pathogens and apoptotic bodies, which exhibits important roles in modulating immune responses. It was displayed in our study that SP-D was greatly decreased in pneumonia mice models. SP-D was predicted as a downstream target of miR-182-5p. These data concluded that miR-182-5p promoted intestinal injury in S. aureus pneumonia-induced sepsis via targeting SP-D.


Assuntos
Mucosa Intestinal/patologia , MicroRNAs/genética , Pneumonia Estafilocócica/patologia , Proteína D Associada a Surfactante Pulmonar/metabolismo , Animais , Apoptose/genética , Sobrevivência Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Células Epiteliais/patologia , Técnicas de Inativação de Genes , Inflamação/patologia , Interleucina-6/metabolismo , Mucosa Intestinal/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Oncogenes/genética , Pneumonia Estafilocócica/genética , Sepse/patologia , Transdução de Sinais , Staphylococcus aureus/patogenicidade , Fator de Necrose Tumoral alfa/metabolismo
3.
Pak J Pharm Sci ; 32(4): 1621-1630, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31608882

RESUMO

Staphylococcus aureus and Pseudomonas aeruginosa are largely the cause of morbidity and mortality in both hospital and community settings. These pathogens remain the important cause of pulmonary infections in patients with cystic fibrosis with a worldwide prevalence. Although, antibiotics are efficient measures of treating bacterial lung infections, the occurrence of antibiotic resistant bacteria has been encouraging the researchers to explore novel therapeutic approaches. It has been discovered that certain lactic acid bacteria possess protective effects against bacterial and viral respiratory infections. The aim of present study was to investigate the capability of orally administered L. acidophilus to ameliorate S. aureus and P. aeruginosa pulmonary infections. Animals were exposed to aerosol of pathogenic suspension. After 24 hours of infection, L. acidophilus treatment was administered orally for 7 consecutive days. Evaluation of tissue bacteriology, histopathology and serum cytokinomics were performed. In parallel, human alveolar A549 cells were utilized to determine possible role of probiotic on pulmonary infections. Oral administration of L. acidophilus significantly (P<0.05) alleviate lung bacterial load and severity of infection as depicted by our histopathological studies. Results obtained from cytokinomics revealed that pro-inflammatory cytokines induced due to lung infection were suppressed in oral probiotic treatment groups. In addition, treatment with L. acidophilus induced murine lung anti inflammatory, IL-10 cytokine level. Current work suggests that orally administered L. acidophilus in mice is able to attenuate S. aureus and P. aeruginosa induced lung cytotoxicity by modulation of host immune response.


Assuntos
Lactobacillus acidophilus , Pneumonia Estafilocócica/terapia , Probióticos/farmacologia , Infecções por Pseudomonas/terapia , Células A549 , Administração Oral , Animais , Citocinas/sangue , Citocinas/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II/metabolismo , Pneumonia Estafilocócica/patologia , Probióticos/administração & dosagem , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa
4.
Ann Pharmacother ; 53(6): 627-638, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30600697

RESUMO

OBJECTIVE: To describe the diagnostic performance characteristics of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening for patients with pneumonia. DATA SOURCES: PubMed and Scopus were searched from 1 January 1990 to 12 December 2018 using terms methicillin-resistant Staphylococcus aureus AND (screening OR active surveillance OR surveillance culture OR targeted surveillance OR chromogenic OR PCR OR polymerase chain reaction OR rapid test) AND (nares OR nasal) AND (pneumonia OR respiratory). STUDY SELECTION AND DATA EXTRACTION: Relevant studies in humans and English were considered. DATA SYNTHESIS: In all, 19 studies, including 21 790 patients, were included. Nasal screening for MRSA had a high negative predictive value (NPV; 76% to 99.4% for relevant studies) across all types of pneumonia. Time from nasal screening to culture varied across studies. Relevance to Patient Care and Clinical Practice: MRSA nasal screening has a high NPV for MRSA involvement in pneumonia. Utilizing this test for antimicrobial stewardship program (ASP) purposes can provide a valuable tool for reducing unwarranted anti-MRSA agents and may provide additional cost benefits. A cutoff of 7 days between nasal swab and culture or infection onset seems most appropriate for use of this test for anti-MRSA agent de-escalation for ASP purposes. CONCLUSIONS: Consideration for the inclusion of the utility of MRSA nasal screening in MRSA pneumonia should be made for future pneumonia and ASP guidelines. Additional studies are warranted to fully evaluate specific pneumonia classifications, culture types, culture timing, and clinical outcomes associated with the use of this test in patients with pneumonia.


Assuntos
Programas de Rastreamento/métodos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Pneumonia Estafilocócica/diagnóstico , Infecções Estafilocócicas/diagnóstico , Feminino , Humanos , Masculino , Meticilina , Pessoa de Meia-Idade , Pneumonia Estafilocócica/patologia , Infecções Estafilocócicas/patologia
5.
Clin Infect Dis ; 68(3): 365-372, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-29893805

RESUMO

Background: Coinfection with influenza virus and methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening necrotizing pneumonia in children. Sporadic incidence precludes evaluation of antimicrobial efficacy. We assessed the clinical characteristics and outcomes of critically ill children with influenza-MRSA pneumonia and evaluated antibiotic use. Methods: We enrolled children (<18 years) with influenza infection and respiratory failure across 34 pediatric intensive care units 11/2008-5/2016. We compared baseline characteristics, clinical courses, and therapies in children with MRSA coinfection, non-MRSA bacterial coinfection, and no bacterial coinfection. Results: We enrolled 170 children (127 influenza A, 43 influenza B). Children with influenza-MRSA pneumonia (N = 30, 87% previously healthy) were older than those with non-MRSA (N = 61) or no (N = 79) bacterial coinfections. Influenza-MRSA was associated with increased leukopenia, acute lung injury, vasopressor use, extracorporeal life support, and mortality than either group (P ≤ .0001). Influenza-related mortality was 40% with MRSA compared to 4.3% without (relative risk [RR], 9.3; 95% confidence interval [CI], 3.8-22.9). Of 29/30 children with MRSA who received vancomycin within the first 24 hours of hospitalization, mortality was 12.5% (N = 2/16) if treatment also included a second anti-MRSA antibiotic compared to 69.2% (N = 9/13) with vancomycin monotherapy (RR, 5.5; 95% CI, 1.4, 21.3; P = .003). Vancomycin dosing did not influence initial trough levels; 78% were <10 µg/mL. Conclusions: Influenza-MRSA coinfection is associated with high fatality in critically ill children. These data support early addition of a second anti-MRSA antibiotic to vancomycin in suspected severe cases.


Assuntos
Antibacterianos/uso terapêutico , Coinfecção/tratamento farmacológico , Estado Terminal , Influenza Humana/complicações , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Pneumonia Estafilocócica/tratamento farmacológico , Vancomicina/uso terapêutico , Adolescente , Criança , Pré-Escolar , Coinfecção/microbiologia , Coinfecção/mortalidade , Coinfecção/patologia , Feminino , Humanos , Lactente , Recém-Nascido , Influenza Humana/mortalidade , Influenza Humana/patologia , Masculino , Pneumonia Estafilocócica/microbiologia , Pneumonia Estafilocócica/mortalidade , Pneumonia Estafilocócica/patologia , Estudos Prospectivos , Análise de Sobrevida , Resultado do Tratamento
6.
Acta Cir Bras ; 33(11): 983-990, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30517325

RESUMO

PURPOSE: To investigate the efficacy and mechanisms of root tuber of Polygonum ciliinerve (Nakai) ohwi (rPC) which has been used to treat bacterial infection in traditional Chinese medicine. METHODS: With the mouse model of Staphylococcus aureus (S. aureus) pneumonia, the phenotype of rPC treated mice, including body weight, mortality, lung slices and bacterial burden were evaluated. Furthermore, inflammatory factors in bronchoalveolar lavage (BAL) were determined by ELISA and the distribution of T cells in lung was assessed by immunofluorescence assay. RESULTS: rPC treatment could dose-dependently reduce weight loss and mortality in S. aureus-infected mice. Upon 10 mg/ml rPC treatment, S. aureus-infected mice showed about 8 grams increase in body weight (P<0.001) and 50% enhancement in mortality. The integrity of lung tissue and bacterial burden were also improved by rPC treatment. Moreover, rPC was found to modulate the immune response in infection. CONCLUSION: rPC has therapeutic potential for S. aureus infections and pneumonia with immunomodulatory functions.


Assuntos
Antibacterianos/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Imunomodulação/efeitos dos fármacos , Pneumonia Estafilocócica/prevenção & controle , Polygonum/química , Substâncias Protetoras/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Líquido da Lavagem Broncoalveolar/química , Quimiocina CCL2/análise , Contagem de Colônia Microbiana , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Interleucina-6/análise , Pulmão/efeitos dos fármacos , Pulmão/patologia , Camundongos Endogâmicos C57BL , Pneumonia Estafilocócica/tratamento farmacológico , Pneumonia Estafilocócica/patologia , Reprodutibilidade dos Testes , Fatores de Tempo , Resultado do Tratamento , Fator de Necrose Tumoral alfa/análise
7.
Acta cir. bras ; 33(11): 983-990, Nov. 2018. graf
Artigo em Inglês | LILACS | ID: biblio-973479

RESUMO

Abstract Purpose: To investigate the efficacy and mechanisms of root tuber of Polygonum ciliinerve (Nakai) ohwi (rPC) which has been used to treat bacterial infection in traditional Chinese medicine. Methods: With the mouse model of Staphylococcus aureus (S. aureus) pneumonia, the phenotype of rPC treated mice, including body weight, mortality, lung slices and bacterial burden were evaluated. Furthermore, inflammatory factors in bronchoalveolar lavage (BAL) were determined by ELISA and the distribution of T cells in lung was assessed by immunofluorescence assay. Results: rPC treatment could dose-dependently reduce weight loss and mortality in S. aureus-infected mice. Upon 10 mg/ml rPC treatment, S. aureus-infected mice showed about 8 grams increase in body weight (P<0.001) and 50% enhancement in mortality. The integrity of lung tissue and bacterial burden were also improved by rPC treatment. Moreover, rPC was found to modulate the immune response in infection. Conclusion: rPC has therapeutic potential for S. aureus infections and pneumonia with immunomodulatory functions.


Assuntos
Animais , Pneumonia Estafilocócica/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Substâncias Protetoras/farmacologia , Polygonum/química , Imunomodulação/efeitos dos fármacos , Antibacterianos/farmacologia , Pneumonia Estafilocócica/patologia , Pneumonia Estafilocócica/tratamento farmacológico , Fatores de Tempo , Ensaio de Imunoadsorção Enzimática , Líquido da Lavagem Broncoalveolar/química , Imuno-Histoquímica , Contagem de Colônia Microbiana , Reprodutibilidade dos Testes , Interleucina-6/análise , Fator de Necrose Tumoral alfa/análise , Resultado do Tratamento , Quimiocina CCL2/análise , Pulmão/efeitos dos fármacos , Pulmão/patologia , Camundongos Endogâmicos C57BL
8.
Cell Host Microbe ; 23(5): 594-606.e7, 2018 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-29706505

RESUMO

Staphylococcus aureus is a commensal bacterium that can asymptomatically colonize its host but also causes invasive infections. Quorum sensing regulates S. aureus virulence and the transition from a commensal to a pathogenic organism. However, little is known about how host innate immunity affects interbacterial communication. We show that nitric oxide suppresses staphylococcal virulence by targeting the Agr quorum sensing system. Nitric oxide-mediated inhibition occurs through direct modification of cysteine residues C55, C123, and C199 of the AgrA transcription factor. Cysteine modification decreases AgrA promoter occupancy as well as transcription of the agr operon and quorum sensing-activated toxin genes. In a staphylococcal pneumonia model, mice lacking inducible nitric oxide synthase develop more severe disease with heightened mortality and proinflammatory cytokine responses. In addition, staphylococcal α-toxin production increases in the absence of nitric oxide or nitric oxide-sensitive AgrA cysteine residues. Our findings demonstrate an anti-virulence mechanism for nitric oxide in innate immunity.


Assuntos
Comunicação Celular/imunologia , Comunicação Celular/fisiologia , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/fisiologia , Óxido Nítrico/antagonistas & inibidores , Staphylococcus/efeitos dos fármacos , Staphylococcus/patogenicidade , Animais , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Cisteína , Citocinas/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas Hemolisinas/metabolismo , Imunidade Inata , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase Tipo II/genética , Óperon , Pneumonia Estafilocócica/metabolismo , Pneumonia Estafilocócica/patologia , Regiões Promotoras Genéticas/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Percepção de Quorum/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Transativadores/metabolismo , Fatores de Transcrição/efeitos dos fármacos , Virulência/efeitos dos fármacos
9.
World J Microbiol Biotechnol ; 34(5): 64, 2018 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-29671126

RESUMO

Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that causes various diseases in both humans and animals. With the increased prevalence of methicillin-resistant S. aureus, the therapeutic effects of commonly used antibiotics are limited against S. aureus infection. Novel treatment strategies and new antibiotics are needed urgently to address this concern. Many studies have shown that virulence factors secreted from S. aureus play vital roles in their pathogenic processes. Alpha-hemolysin (Hla), an important exotoxin in S. aureus, is one such virulence factor that increases sensitivity of multiple host cells to S. aureus resulting in various diseases. Eriodictyol is a flavonoid compound that exists in many fruits and vegetables. In this study, eriodictyol was demonstrated to inhibit the expression of Hla by hemolysis assays, western blotting, and RT-qPCR at the sub-minimal inhibitory concentration. In live/dead and cytotoxicity assays, the results showed that eriodictyol protected A549 cells against Hla-induced injury in a dose-dependent manner. The minimal inhibitory concentration of eriodictyol against S. aureus was 512 µg/mL. Eriodictyol can downregulate S. aureus Hla at both the expressional and transcriptional levels without affecting S. aureus growth. In addition, cell assays had proved that eriodictyol could protect A549 cells against Hla damage. Eriodictyol could therefore have the potential to treat S. aureus infection targeting Hla.


Assuntos
Antibacterianos/farmacologia , Toxinas Bacterianas/toxicidade , Flavanonas/farmacologia , Proteínas Hemolisinas/efeitos dos fármacos , Proteínas Hemolisinas/toxicidade , Lesão Pulmonar/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Células A549/efeitos dos fármacos , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Regulação para Baixo/efeitos dos fármacos , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Hemólise , Humanos , Lesão Pulmonar/microbiologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/metabolismo , Testes de Sensibilidade Microbiana , Pneumonia Estafilocócica/microbiologia , Pneumonia Estafilocócica/patologia , Pneumonia Estafilocócica/prevenção & controle , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/metabolismo , Staphylococcus aureus/patogenicidade , Fatores de Virulência/metabolismo
10.
Cell Death Dis ; 9(3): 362, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29500427

RESUMO

Given its high resistance, enhanced virulence, and high transmissibility, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) pneumonia is highly associated with high morbidity and mortality. Anti-virulence therapy is a promising strategy that bypasses the evolutionary pressure on the bacterium to develop resistance. RNAIII-inhibiting peptide (RIP), as an accessory gene regulator (agr)-specific inhibitor, significantly restricts the virulence of S. aureus and protects infected mice from death by blocking the agr quorum sensing system. The protective effects of RIP on the neutropenic mice completely disappeared in a neutrophil-deleted mouse infection model, but not in the macrophage-deleted mice. This result confirmed that the in vivo antibacterial activity of RIP is highly associated with neutrophil function. Phenol-soluble modulins (PSMs), as major leukocyte lysis toxins of CA-MRSA, are directly regulated by the agr system. In this experiment, PSMα1, 2, and 3 significantly induced neutrophil necroptosis by activating mixed lineage kinase-like protein (MLKL) phosphorylation and increasing lactate dehydrogenase release. The S. aureus supernatants harvested from the agr or psmα mutant strains both decreased the phosphorylation level of MLKL and cell lysis. PSMα1-mediated neutrophil lysis was significantly inhibited by necrosulfonamide, necrostatin-1, TNFα antibody, and WRW4. These results showed PSMα1 induced necroptosis depends on formylpeptide receptor 2 (FPR2)-mediated autocrine TNFα. Moreover, the neutrophil necroptosis induced by S. aureus was significantly suppressed and pneumonia was effectively prevented by the blockage of agrA and psmα expression levels. These findings indicate that PSMα-induced necroptosis is a major cause of lung pathology in S. aureus pneumonia and suggest that interfering with the agr quorum sensing signaling pathway is a potential therapeutic strategy.


Assuntos
Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Pulmão/patologia , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Neutrófilos/metabolismo , Pneumonia Estafilocócica/patologia , Transativadores/metabolismo , Animais , Anticorpos/metabolismo , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Camundongos , Camundongos Endogâmicos BALB C , Necrose , Fosforilação , Proteínas Quinases/metabolismo , Fator de Necrose Tumoral alfa/imunologia , Virulência
11.
J Infect Dis ; 218(4): 659-668, 2018 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-29378030

RESUMO

Staphylococcus aureus is a major cause of both community- and healthcare-acquired pneumonias. Inducible costimulator (ICOS) is part of the CD28 family of proteins and is a target for immune checkpoint therapy. We found ICOS highly expressed on activated CD4 cells in response to S. aureus. In the absence of ICOS, mice had improved survival in a pneumonia model with the methicillin-resistant Staphylococcus aureus (MRSA) strain USA300 and significant reductions in bacterial burden in a nonlethal acute pneumonia model. Infected Icos-/- mice had major reductions in several proinflammatory cytokines, neutrophils, inflammatory monocytes, and eosinophils compared to infected wild-type mice, while there was improved expression of CD11c and macrophage receptor with collagenous structure on the surface of alveolar macrophages. Early during infection infected Icos-/- mice had increased numbers of alveolar macrophages and expression of several surface markers on alveolar macrophages and neutrophils. ICOS signaling also contributed to the pathogenesis of the airway pathogens Klebsiella pneumoniae, Pseudomonas aeruginosa, and Streptococcus pneumoniae, and neutralizing antibody to ICOS led to improved clearance of S. aureus from the airway. Our results indicate that ICOS plays a significant role in orchestrating the innate immune response to S. aureus and other airway pathogens, and could be a potential immunomodulatory target to attenuate S. aureus-related immunopathology.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Interações Hospedeiro-Patógeno , Imunidade Inata , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Pneumonia Estafilocócica/patologia , Animais , Carga Bacteriana , Modelos Animais de Doenças , Fatores Imunológicos/análise , Proteína Coestimuladora de Linfócitos T Induzíveis/deficiência , Infecções por Klebsiella/patologia , Pulmão/patologia , Macrófagos Alveolares/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções Pneumocócicas/patologia , Pneumonia Estafilocócica/microbiologia , Infecções por Pseudomonas/patologia , Análise de Sobrevida
12.
Physiol Rep ; 5(21)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29142002

RESUMO

Staphylococcus aureus is an important cause of acute bacterial pneumonia. Toll-like receptor 2 (TLR2) recognizes multiple components of the bacterial cell wall and activates innate immune responses to gram-positive bacteria. We hypothesized that TLR2 would have an important role in pulmonary host defense against S. aureus TLR null (TLR2-/-) mice and wild type (WT) C57BL/6 controls were challenged with aerosolized S. aureus at a range of inocula for kinetic studies of cytokine and antimicrobial peptide expression, lung inflammation, bacterial killing by alveolar macrophages, and bacterial clearance. Survival was measured after intranasal infection. Pulmonary induction of most pro-inflammatory cytokines was significantly blunted in TLR2-/- mice 4 and 24 h after infection in comparison with WT controls. Bronchoalveolar concentrations of cathelicidin-related antimicrobial peptide also were reduced in TLR2-/- mice. Lung inflammation, measured by enumeration of bronchoalveolar neutrophils and scoring of histological sections, was significantly blunted in TLR2-/- mice. Phagocytosis of S. aureus by alveolar macrophages in vivo after low-dose infection was unimpaired, but viability of ingested bacteria was significantly greater in TLR2-/- mice. Bacterial clearance from the lungs was slightly impaired in TLR2-/- mice after low-dose infection only; bacterial elimination from the lungs was slightly accelerated in the TLR2-/- mice after high-dose infection. Survival after high-dose intranasal challenge was 50-60% in both groups. TLR2 has a significant role in early innate immune responses to S. aureus in the lungs but is not required for bacterial clearance and survival from S. aureus pneumonia.


Assuntos
Pneumonia Estafilocócica/imunologia , Staphylococcus aureus , Receptor 2 Toll-Like/imunologia , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Carga Bacteriana , Líquido da Lavagem Broncoalveolar/imunologia , Contagem de Colônia Microbiana , Citocinas/biossíntese , Feminino , Imunidade Inata , Pulmão/microbiologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/microbiologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fagocitose/imunologia , Pneumonia Estafilocócica/microbiologia , Pneumonia Estafilocócica/patologia , Staphylococcus aureus/crescimento & desenvolvimento , Receptor 2 Toll-Like/deficiência
13.
Infect Immun ; 85(12)2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28893917

RESUMO

Influenza A virus (IAV) infection is often followed by secondary bacterial lung infection, which is a major reason for severe, often fatal pneumonia. Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains such as USA300 cause particularly severe and difficult-to-treat cases of IAV-associated pneumonia. CA-MRSA strains are known to produce extraordinarily large amounts of phenol-soluble modulin (PSM) peptides, which are important cytotoxins and proinflammatory molecules that contribute to several types of S. aureus infection. However, their potential role in pneumonia has remained elusive. We determined the impact of PSMs on human lung epithelial cells and found that PSMs are cytotoxic and induce the secretion of the proinflammatory cytokine interleukin-8 (IL-8) in these cells. Both effects were boosted by previous infection with the 2009 swine flu pandemic IAV H1N1 strain, suggesting that PSMs may contribute to lung inflammation and damage in IAV-associated S. aureus pneumonia. Notably, the PSM-producing USA300 strain caused a higher mortality rate than did an isogenic PSM-deficient mutant in a mouse IAV-S. aureus pneumonia coinfection model, indicating that PSMs are major virulence factors in IAV-associated S. aureus pneumonia and may represent important targets for future anti-infective therapies.


Assuntos
Toxinas Bacterianas/metabolismo , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Influenza Humana/complicações , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Pneumonia Estafilocócica/patologia , Fatores de Virulência/metabolismo , Animais , Linhagem Celular , Modelos Animais de Doenças , Células Epiteliais/microbiologia , Células Epiteliais/fisiologia , Humanos , Influenza Humana/virologia , Staphylococcus aureus Resistente à Meticilina/metabolismo , Camundongos , Análise de Sobrevida , Suínos
14.
Am J Physiol Lung Cell Mol Physiol ; 313(4): L699-L709, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28663335

RESUMO

Mitochondrial damage is often overlooked in acute lung injury (ALI), yet most of the lung's physiological processes, such as airway tone, mucociliary clearance, ventilation-perfusion (Va/Q) matching, and immune surveillance require aerobic energy provision. Because the cell's mitochondrial quality control (QC) process regulates the elimination and replacement of damaged mitochondria to maintain cell survival, we serially evaluated mitochondrial biogenesis and mitophagy in the alveolar regions of mice in a validated Staphylococcus aureus pneumonia model. We report that apart from cell lysis by direct contact with microbes, modest epithelial cell death was detected despite significant mitochondrial damage. Cell death by TdT-mediated dUTP nick-end labeling staining occurred on days 1 and 2 postinoculation: apoptosis shown by caspase-3 cleavage was present on days 1 and 2, while necroptosis shown by increased levels of phospho- mixed lineage kinase domain-like protein (MLKL) and receptor-interacting serine/threonine-protein kinase 1 (RIPK1) was present on day 1 Cell death in alveolar type I (AT1) cells assessed by bronchoalveolar lavage fluid receptor for advanced glycation end points (RAGE) levels was high, yet AT2 cell death was limited while both mitochondrial biogenesis and mitophagy were induced. These mitochondrial QC mechanisms were evaluated mainly in AT2 cells by localizing increases in citrate synthase content, increases in nuclear mitochondrial biogenesis regulators nuclear respiratory factor-1 (NRF-1) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), and increases in light chain 3B protein (LC3-I)/LC3II ratios. Concomitant changes in p62, Pink 1, and Parkin protein levels indicated activation of mitophagy. By confocal microscopy, mitochondrial biogenesis and mitophagy were often observed on day 1 within the same AT2 cells. These findings imply that mitochondrial QC activation in pneumonia-damaged AT2 cells promotes cell survival in support of alveolar function.


Assuntos
Células Epiteliais Alveolares/patologia , Mitocôndrias/patologia , Pneumonia Estafilocócica/etiologia , Pneumonia Estafilocócica/patologia , Infecções Estafilocócicas/complicações , Staphylococcus aureus/patogenicidade , Células Epiteliais Alveolares/metabolismo , Animais , Apoptose , Biomarcadores/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Pneumonia Estafilocócica/metabolismo , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/patologia
15.
Infect Immun ; 85(5)2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28289144

RESUMO

Staphylococcus aureus plays an important role in sepsis, pneumonia, wound infections, and cystic fibrosis (CF), which is caused by mutations of the cystic fibrosis transmembrane conductance regulator (Cftr). Pulmonary S. aureus infections in CF often occur very early and prior to colonization with other pathogens, in particular Pseudomonas aeruginosa Here, we demonstrate that CF mice are highly susceptible to pulmonary infections with S. aureus and fail to clear the pathogen during infection. S. aureus is internalized by Cftr-deficient macrophages in the lung, but these macrophages are unable to kill intracellular bacteria. This failure might be caused by a defect in the fusion of phagosomes with lysosomes, while this process occurs rapidly in wild-type macrophages and serves to kill intracellular pathogens. Transplantation of infected Cftr-deficient alveolar macrophages into the lungs of noninfected CF mice is sufficient to induce pneumonia. This suggests that intracellular survival of S. aureus in macrophages may allow the pathogen to chronically infect CF lungs.


Assuntos
Fibrose Cística/complicações , Macrófagos Alveolares/microbiologia , Pneumonia Estafilocócica/patologia , Staphylococcus aureus/fisiologia , Adulto , Animais , Doença Crônica , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Humanos , Pulmão/microbiologia , Pulmão/patologia , Camundongos Endogâmicos C57BL , Viabilidade Microbiana , Pessoa de Meia-Idade , Análise de Sobrevida , Adulto Jovem
16.
Diagn Microbiol Infect Dis ; 86(3): 300-302, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27608537

RESUMO

Telavancin is approved in the United States and Europe for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia caused by Staphylococcus aureus. This study provides a current in vitro activity analysis for telavancin and comparators against 1353 United States S. aureus causing pneumonia in hospitalized patients during 2013-2014. Telavancin was found to exhibit potent activity (MIC90, 0.06µg/mL; 16-fold more active than vancomycin or linezolid) against all S. aureus isolates, including the HABP subset, multidrug-resistant isolates, and those less susceptible to vancomycin.


Assuntos
Aminoglicosídeos/farmacologia , Antibacterianos/farmacologia , Pneumonia Estafilocócica/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Hospitalização , Humanos , Lipoglicopeptídeos , Testes de Sensibilidade Microbiana , Pneumonia Estafilocócica/patologia , Estados Unidos
17.
PLoS One ; 11(7): e0158799, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27391952

RESUMO

Ventilator-associated pneumonia (VAP) is common during mechanical ventilation (MV). Beside obvious deleterious effects on muco-ciliary clearance, MV could adversely shift the host immune response towards a pro-inflammatory pattern through toll-like receptor (TLRs) up-regulation. We tested this hypothesis in a rabbit model of Staphylococcus aureus VAP. Pneumonia was caused by airway challenge with S. aureus, in either spontaneously breathing (SB) or MV rabbits (n = 13 and 17, respectively). Pneumonia assessment regarding pulmonary and systemic bacterial burden, as well as inflammatory response was done 8 and 24 hours after S. aureus challenge. In addition, ex vivo stimulations of whole blood taken from SB or MV rabbits (n = 7 and 5, respectively) with TLR2 agonist or heat-killed S. aureus were performed. Data were expressed as mean±standard deviation. After 8 hours of infection, lung injury was more severe in MV animals (1.40±0.33 versus [vs] 2.40±0.55, p = 0.007), along with greater bacterial concentrations (6.13±0.63 vs. 4.96±1.31 colony forming units/gram, p = 0.002). Interleukin (IL)-8 and tumor necrosis factor (TNF)-αserum concentrations reached higher levels in MV animals (p = 0.010). Whole blood obtained from MV animals released larger amounts of cytokines if stimulated with TLR2 agonist or heat-killed S. aureus (e.g., TNF-α: 1656±166 vs. 1005±89; p = 0.014). Moreover, MV induced TLR2 overexpression in both lung and spleen tissue. MV hastened tissue injury, impaired lung bacterial clearance, and promoted a systemic inflammatory response, maybe through TLR2 overexpression.


Assuntos
Pneumonia Estafilocócica/imunologia , Pneumonia Associada à Ventilação Mecânica/imunologia , Respiração Artificial , Staphylococcus aureus/imunologia , Animais , Interleucina-8/imunologia , Pneumonia Estafilocócica/patologia , Pneumonia Associada à Ventilação Mecânica/microbiologia , Pneumonia Associada à Ventilação Mecânica/patologia , Coelhos , Receptor 2 Toll-Like/imunologia , Fator de Necrose Tumoral alfa/imunologia
18.
Sci Signal ; 9(418): ra26, 2016 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-26956485

RESUMO

In phagocytes, pathogen recognition is followed by Ca(2+) mobilization and NADPH oxidase 2 (NOX2)-mediated "oxidative burst," which involves the rapid production of large amounts of reactive oxygen species (ROS). We showed that ORAI Ca(2+) channels control store-operated Ca(2+) entry, ROS production, and bacterial killing in primary human monocytes. ROS inactivate ORAI channels that lack an ORAI3 subunit. Staphylococcal infection of mice reduced the expression of the gene encoding the redox-sensitive Orai1 and increased the expression of the gene encoding the redox-insensitive Orai3 in the lungs or in bronchoalveolar lavages. A similar switch from ORAI1 to ORAI3 occurred in primary human monocytes exposed to bacterial peptides in culture. These alterations in ORAI1 and ORAI3 abundance shifted the channel assembly toward a more redox-insensitive configuration. Accordingly, silencing ORAI3 increased the redox sensitivity of the channel and enhanced oxidation-induced inhibition of NOX2. We generated a mathematical model that predicted additional features of the Ca(2+)-redox interplay. Our results identified the ORAI-NOX2 feedback loop as a determinant of monocyte immune responses.


Assuntos
Canais de Cálcio Ativados pela Liberação de Cálcio/imunologia , Cálcio/imunologia , Modelos Biológicos , Monócitos/imunologia , Pneumonia Estafilocócica/imunologia , Espécies Reativas de Oxigênio/imunologia , Staphylococcus aureus/imunologia , Animais , Cálcio/metabolismo , Canais de Cálcio Ativados pela Liberação de Cálcio/genética , Canais de Cálcio Ativados pela Liberação de Cálcio/metabolismo , Feminino , Humanos , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Glicoproteínas de Membrana/metabolismo , Camundongos , Monócitos/metabolismo , Monócitos/patologia , NADPH Oxidase 2 , NADPH Oxidases/genética , NADPH Oxidases/imunologia , NADPH Oxidases/metabolismo , Oxirredução , Pneumonia Estafilocócica/genética , Pneumonia Estafilocócica/metabolismo , Pneumonia Estafilocócica/patologia , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/metabolismo
19.
PLoS One ; 11(3): e0149233, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26974438

RESUMO

The spread of methicillin-resistant Staphylococcus aureus (MRSA) is a critical health issue that has drawn greater attention to the potential use of immunotherapy. Toll-like receptor 2 (TLR2), a pattern recognition receptor, is an essential component in host innate defense system against S. aureus infection. However, little is known about the innate immune response, specifically TLR2 activation, against MRSA infection. Here, we evaluate the protective effect and the mechanism of MRSA murine pneumonia after pretreatment with Pam3CSK4, a TLR2 agonist. We found that the MRSA-pneumonia mouse model, pretreated with Pam3CSK4, had reduced bacteria and mortality in comparison to control mice. As well, lower protein and mRNA levels of TNF-α, IL-1ß and IL-6 were observed in lungs and bronchus of the Pam3CSK4 pretreatment group. Conversely, expression of anti-inflammatory cytokine IL-10, but not TGF-ß, increased in Pam3CSK4-pretreated mice. Our additional studies showed that CXCL-2 and CXCL1, which are necessary for neutrophil recruitment, were less evident in the Pam3CSK4-pretreated group compared to control group, whereas the expression of Fcγ receptors (FcγⅠ/Ⅲ) and complement receptors (CR1/3) increased in murine lungs. Furthermore, we found that increased survival and improved bacterial clearance were not a result of higher levels of neutrophil infiltration, but rather a result of enhanced phagocytosis and bactericidal activity of neutrophils in vitro and in vivo as well as increased robust oxidative activity and release of lactoferrin. Our cumulative findings suggest that Pam3CSK4 could be a novel immunotherapeutic candidate against MRSA pneumonia.


Assuntos
Lipopeptídeos/farmacologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Pneumonia Estafilocócica/tratamento farmacológico , Receptor 2 Toll-Like/agonistas , Animais , Citocinas/imunologia , Antígeno de Macrófago 1/imunologia , Camundongos , Pneumonia Estafilocócica/imunologia , Pneumonia Estafilocócica/patologia , Receptores de Complemento 3b/imunologia , Receptores de IgG/imunologia , Receptor 2 Toll-Like/imunologia
20.
Shock ; 46(2): 164-72, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26849628

RESUMO

UNLABELLED: Staphylococcus aureus pneumonia is an important cause of sepsis which causes gut injury, inflammation, and apoptosis. The surfactant proteins surfactant protein A (SP-A) and surfactant protein D (SP-D) bind bacterial pathogens and facilitate clearance of pathogens, apoptotic bodies, and modulate immune responses. SP-A and SP-D are expressed in both lung and gut epithelia. We hypothesize SP-A and SP-D regulate pneumonia severity and gut injury during pneumonia. METHODS: Wild-type (WT) and SP-A and SP-D double knockout (SP-A/D KO) mice were subjected to S. aureus or sham pneumonia. Bronchoalveolar lavage and tissue harvest were performed 24 h later. Pneumonia severity, gut mucosal injury, inflammation, and apoptosis were measured using a combination of histology, immunohistochemistry, cytokine assay, TUNEL assay, quantitative real-time polymerase chain reaction, and Western blot analyses. RESULTS: Pneumonia increased gut inflammation, apoptosis, and mucosal injury in both groups. Pneumonia histology and bacterial growth in bronchoalveolar lavage fluid demonstrate more severe infection in SP-A/D KO mice compared with WT controls. SP-A/D KO mice with pneumonia also demonstrate more severe histologic gut mucosal injury, increased gut apoptosis, elevated caspase-3 levels, and Bax/Bcl-2 mRNA expression compared with WT pneumonia mice. Nuclear factor κB (NF-κB) p65 expression and its nuclear translocation, gut levels of tumor necrosis factor α and interleukin-1ß were all increased in SP-A/D KO mice with pneumonia compared with WT controls. CONCLUSIONS: These data provide evidence SP-A and SP-D attenuate S. aureus pneumonia severity resulting in decreased intestinal mucosal injury, apoptosis, and inflammation. Improved pulmonary clearance of S. aureus decreased caspase-3 and Bax/Bcl-2 expressions and decreased activation of the NF-κB signaling pathway in intestine represent potential mechanisms for the effects of SP-A and SP-D on gut injury during pneumonia.


Assuntos
Pneumonia Estafilocócica/imunologia , Pneumonia Estafilocócica/patologia , Proteína A Associada a Surfactante Pulmonar/metabolismo , Proteína D Associada a Surfactante Pulmonar/metabolismo , Animais , Apoptose/fisiologia , Líquido da Lavagem Broncoalveolar/microbiologia , Caspase 3/genética , Caspase 3/metabolismo , Modelos Animais de Doenças , Feminino , Intestinos/citologia , Intestinos/imunologia , Pulmão/citologia , Pulmão/imunologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pneumonia Estafilocócica/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína A Associada a Surfactante Pulmonar/genética , Proteína D Associada a Surfactante Pulmonar/genética , Transdução de Sinais , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
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