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1.
Artigo em Inglês | MEDLINE | ID: mdl-29133571

RESUMO

The recommended management of inhalational anthrax, a high-priority bioterrorist threat, includes antibiotics and antitoxins. Obiltoxaximab, a chimeric monoclonal antibody against anthrax protective antigen (PA), is licensed under the U.S. Food and Drug Administration's (FDA's) Animal Rule for the treatment of inhalational anthrax. Because of spore latency, disease reemergence after treatment cessation is a concern, and there is a need to understand the development of endogenous protective immune responses following antitoxin-containing anthrax treatment regimens. Here, acquired protective immunity was examined in New Zealand White (NZW) rabbits challenged with a targeted lethal dose of Bacillus anthracis spores and treated with antibiotics, obiltoxaximab, or a combination of both. Survivors of the primary challenge were rechallenged 9 months later and monitored for survival. Survival rates after primary and rechallenge for controls and animals treated with obiltoxaximab, levofloxacin, or a combination of both were 0, 65, 100, and 95%, and 0, 100, 95, and 89%, respectively. All surviving immune animals had circulating antibodies to PA and serum toxin-neutralizing titers prior to rechallenge. Following rechallenge, systemic bacteremia and toxemia were not detected in most animals, and the levels of circulating anti-PA IgG titers increased starting at 5 days postrechallenge. We conclude that treatment with obiltoxaximab, alone or combined with antibiotics, significantly improves the survival of rabbits that received a lethal inhalation B. anthracis spore challenge dose and does not interfere with the development of immunity. Survivors of primary challenge are protected against reexposure, have rare incidents of systemic bacteremia and toxemia, and have evidence of an anamnestic response.


Assuntos
Antraz , Antibacterianos , Anticorpos Monoclonais , Antitoxinas , Bacillus anthracis , Levofloxacino , Infecções Respiratórias , Esporos Bacterianos , Animais , Feminino , Masculino , Coelhos , Antraz/imunologia , Antraz/microbiologia , Antraz/mortalidade , Antraz/prevenção & controle , Antibacterianos/farmacologia , Anticorpos Antibacterianos/biossíntese , Anticorpos Monoclonais/farmacologia , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Antitoxinas/farmacologia , Bacillus anthracis/efeitos dos fármacos , Bacillus anthracis/imunologia , Bacillus anthracis/patogenicidade , Toxinas Bacterianas/antagonistas & inibidores , Toxinas Bacterianas/sangue , Toxinas Bacterianas/imunologia , Quimioterapia Combinada , Imunização Passiva/métodos , Imunoglobulina G/biossíntese , Memória Imunológica/efeitos dos fármacos , Levofloxacino/farmacologia , Distribuição Aleatória , Infecções Respiratórias/imunologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/mortalidade , Infecções Respiratórias/prevenção & controle , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/imunologia , Esporos Bacterianos/patogenicidade , Análise de Sobrevida
2.
Artigo em Inglês | MEDLINE | ID: mdl-28784679

RESUMO

The fluorocycline TP-271 was evaluated in mouse and nonhuman primate (NHP) models of inhalational anthrax. BALB/c mice were exposed by nose-only aerosol to Bacillus anthracis Ames spores at a level of 18 to 88 lethal doses sufficient to kill 50% of exposed individuals (LD50). When 21 days of once-daily dosing was initiated at 24 h postchallenge (the postexposure prophylaxis [PEP] study), the rates of survival for the groups treated with TP-271 at 3, 6, 12, and 18 mg/kg of body weight were 90%, 95%, 95%, and 84%, respectively. When 21 days of dosing was initiated at 48 h postchallenge (the treatment [Tx] study), the rates of survival for the groups treated with TP-271 at 6, 12, and 18 mg/kg TP-271 were 100%, 91%, and 81%, respectively. No deaths of TP-271-treated mice occurred during the 39-day posttreatment observation period. In the NHP model, cynomolgus macaques received an average dose of 197 LD50 of B. anthracis Ames spore equivalents using a head-only inhalation exposure chamber, and once-daily treatment of 1 mg/kg TP-271 lasting for 14 or 21 days was initiated within 3 h of detection of protective antigen (PA) in the blood. No (0/8) animals in the vehicle control-treated group survived, whereas all 8 infected macaques treated for 21 days and 4 of 6 macaques in the 14-day treatment group survived to the end of the study (56 days postchallenge). All survivors developed toxin-neutralizing and anti-PA IgG antibodies, indicating an immunologic response. On the basis of the results obtained with the mouse and NHP models, TP-271 shows promise as a countermeasure for the treatment of inhalational anthrax.


Assuntos
Antraz/tratamento farmacológico , Antibacterianos/uso terapêutico , Bacillus anthracis/efeitos dos fármacos , Infecções Respiratórias/tratamento farmacológico , Tetraciclinas/uso terapêutico , Animais , Antraz/microbiologia , Antraz/mortalidade , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Antígenos de Bactérias/imunologia , Bacillus anthracis/imunologia , Toxinas Bacterianas/imunologia , Modelos Animais de Doenças , Feminino , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Macaca fascicularis , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Profilaxia Pós-Exposição/métodos , Infecções Respiratórias/microbiologia , Infecções Respiratórias/mortalidade , Esporos Bacterianos , Taxa de Sobrevida , Tetraciclinas/farmacocinética
3.
Artigo em Inglês | MEDLINE | ID: mdl-28559261

RESUMO

TP-271 is a novel, fully synthetic fluorocycline in development for complicated bacterial respiratory infections. TP-271 was active in vitro against a panel of 29 Francisella tularensis isolates, showing MICs against 50% and 90% of isolates of 0.25 and 0.5 µg/ml, respectively. In a mouse model of inhalational tularemia, animals were exposed by aerosol to 91 to 283 50% lethal doses (LD50)/mouse of F. tularensis SCHU S4. Following 21 days of once-daily intraperitoneal dosing with TP-271 at 3, 6, 12, and 18 mg/kg of body weight/day, initiating at 24 h postchallenge, survival was 80%, 100%, 100%, and 100%, respectively. When treatment was initiated at 72 h postchallenge, survival was 89%, 100%, 100%, and 100% in the 3-, 6-, 12-, and 18-mg/kg/day TP-271 groups, respectively. No mice treated with the vehicle control survived. Surviving mice treated with TP-271 showed little to no relapse during 14 days posttreatment. In a nonhuman primate model of inhalational tularemia, cynomolgus macaques received an average aerosol exposure of 1,144 CFU of F. tularensis SCHU S4. Once-daily intravenous infusion with 1 or 3 mg/kg TP-271, or vehicle control, for 21 days was initiated within 6 h of confirmed fever. All animals treated with TP-271 survived to the end of the study, with no relapse during 14 days after the last treatment, whereas no vehicle control-treated animals survived. The protection and low relapse afforded by TP-271 treatment in these studies support continued investigation of TP-271 for use in the event of aerosolized exposure to F. tularensis.


Assuntos
Antibacterianos/uso terapêutico , Francisella tularensis/efeitos dos fármacos , Infecções Respiratórias/tratamento farmacológico , Tetraciclinas/uso terapêutico , Tularemia/tratamento farmacológico , Animais , Modelos Animais de Doenças , Feminino , Macaca fascicularis , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Infecções Respiratórias/microbiologia , Tularemia/microbiologia
4.
Antimicrob Agents Chemother ; 60(10): 5796-805, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27431219

RESUMO

The Centers for Disease Control and Prevention recommend adjunctive antitoxins when systemic anthrax is suspected. Obiltoxaximab, a monoclonal antibody against protective antigen (PA), is approved for treatment of inhalational anthrax in combination with antibiotics and for prophylaxis when alternative therapies are not available. The impact of toxin neutralization with obiltoxaximab during pre- and postexposure prophylaxis was explored, and efficacy results that supported the prophylaxis indication are presented here. New Zealand White rabbits and cynomolgus macaques received obiltoxaximab as a single intramuscular or intravenous dose of 2 to 16 mg/kg of body weight at various times relative to Bacillus anthracis aerosol spore challenge. The primary endpoint was survival, and effect of treatment timing was explored. In rabbits, obiltoxaximab administration 9 h postchallenge singly or combined with a 5-day levofloxacin regimen protected 89% to 100% of animals compared to 33% with levofloxacin monotherapy. In cynomolgus macaques, a single intramuscular dose of 16 mg/kg obiltoxaximab led to 100% survival when given 1 to 3 days preexposure and 83% to 100% survival when given 18 to 24 h postexposure and prior to systemic bacteremia onset. Obiltoxaximab administration after bacteremia onset resulted in lower (25% to 50%) survival rates reflective of treatment setting. Prophylactic administration of obiltoxaximab before spore challenge or to spore-challenged animals before systemic bacterial dissemination is efficacious in promoting survival, ameliorating toxemia, and inhibiting bacterial spread to the periphery.


Assuntos
Antraz/mortalidade , Antraz/prevenção & controle , Anticorpos Monoclonais/farmacologia , Antitoxinas/farmacologia , Bacillus anthracis/patogenicidade , Infecções Respiratórias/mortalidade , Infecções Respiratórias/prevenção & controle , Animais , Antraz/tratamento farmacológico , Antibacterianos/administração & dosagem , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/farmacocinética , Antitoxinas/administração & dosagem , Bacillus anthracis/efeitos dos fármacos , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Modelos Animais de Doenças , Feminino , Injeções Intramusculares , Injeções Intravenosas , Macaca fascicularis , Masculino , Profilaxia Pós-Exposição , Profilaxia Pré-Exposição , Coelhos , Infecções Respiratórias/tratamento farmacológico , Taxa de Sobrevida
5.
Antimicrob Agents Chemother ; 60(10): 5787-95, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27431222

RESUMO

Inhalational anthrax has high mortality even with antibiotic treatment, and antitoxins are now recommended as an adjunct to standard antimicrobial regimens. The efficacy of obiltoxaximab, a monoclonal antibody against anthrax protective antigen (PA), was examined in multiple studies conducted in two animal models of inhalational anthrax. A single intravenous bolus of 1 to 32 mg/kg of body weight obiltoxaximab or placebo was administered to New Zealand White rabbits (two studies) and cynomolgus macaques (4 studies) at disease onset (significant body temperature increase or detection of serum PA) following lethal challenge with aerosolized Bacillus anthracis spores. The primary endpoint was survival. The relationship between efficacy and disease severity, defined by pretreatment bacteremia and toxemia levels, was explored. In rabbits, single doses of 1 to 16 mg/kg obiltoxaximab led to 17 to 93% survival. In two studies, survival following 16 mg/kg obiltoxaximab was 93% and 62% compared to 0% and 0% for placebo (P = 0.0010 and P = 0.0013, respectively). Across four macaque studies, survival was 6.3% to 78.6% following 4 to 32 mg/kg obiltoxaximab. In two macaque studies, 16 mg/kg obiltoxaximab reduced toxemia and led to survival rates of 31%, 35%, and 47% versus 0%, 0%, and 6.3% with placebo (P = 0.0085, P = 0.0053, P = 0.0068). Pretreatment bacteremia and toxemia levels inversely correlated with survival. Overall, obiltoxaximab monotherapy neutralized PA and increased survival across the range of disease severity, indicating clinical benefit of toxin neutralization with obiltoxaximab in both early and late stages of inhalational anthrax.


Assuntos
Antraz/tratamento farmacológico , Antibacterianos/farmacologia , Anticorpos Monoclonais/farmacologia , Antitoxinas/farmacologia , Infecções Respiratórias/tratamento farmacológico , Animais , Antraz/etiologia , Antraz/mortalidade , Antibacterianos/farmacocinética , Anticorpos Monoclonais/farmacocinética , Feminino , Macaca fascicularis , Masculino , Coelhos , Infecções Respiratórias/etiologia , Infecções Respiratórias/mortalidade , Taxa de Sobrevida , Resultado do Tratamento
6.
Sci Rep ; 13(1): 4047, 2023 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-36899021

RESUMO

Melioidosis is an endemic disease in numerous tropical regions. Additionally, the bacterium that causes melioidosis, Burkholderia pseudomallei, has potential to be used as a biological weapon. Therefore, development of effective and affordable medical countermeasures to serve regions affected by the disease and to have medical countermeasures available in the event of a bioterrorism attack remains critical. The current study evaluated the efficacy of eight distinct acute phase ceftazidime treatment regimens administered therapeutically in the murine model. At the conclusion of the treatment period, survival rates were significantly greater in several of the treated groups when compared to the control group. Pharmacokinetics of a single dose of ceftazidime were examined at 150 mg/kg, 300 mg/kg, and 600 mg/kg and were compared to an intravenous clinical dose administered at 2000 mg every eight hours. The clinical dose has an estimated 100% fT > 4*MIC which exceeded the highest murine dose of 300 mg/kg every six hours at 87.2% fT > 4*MIC. Based upon survival at the end of the treatment regimen and supplemented by pharmacokinetic modeling, a daily dose of 1200 mg/kg of ceftazidime, administered every 6 h at 300 mg/kg, provides protection in the acute phase of inhalation melioidosis in the murine model.


Assuntos
Burkholderia pseudomallei , Melioidose , Animais , Camundongos , Ceftazidima/farmacologia , Melioidose/microbiologia , Modelos Animais de Doenças , Aerossóis/farmacologia , Antibacterianos/farmacologia
7.
Antibiotics (Basel) ; 12(8)2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37627757

RESUMO

Francisella tularensis subspecies tularensis is a category-A biothreat agent that can cause lethal tularemia. Ceftobiprole medocaril is being explored as a medical countermeasure for the treatment of pneumonic tularemia. The efficacy of ceftobiprole medocaril against inhalational tularemia was evaluated in the Fischer 344 rat model of infection. The dose was expected to be effective against F. tularensis isolates with ceftobiprole minimum inhibitory concentrations ≤0.5 µg/mL. Animals treated with ceftobiprole medocaril exhibited a 92% survival rate 31 days post-challenge, identical to the survival of levofloxacin-treated rats. By comparison, rats receiving placebo experienced 100% mortality. Terminally collected blood, liver, lung, and spleen samples confirmed disseminated F. tularensis infections in most animals that died prior to completing treatments (placebo animals and a rat treated with ceftobiprole medocaril), although levels of bacteria detected in the placebo samples were significantly elevated compared to the ceftobiprole-medocaril-treated group geometric mean. Furthermore, no evidence of infection was detected in any rat that completed ceftobiprole medocaril or levofloxacin treatment and survived to the end of the post-treatment observation period. Overall, survival rates, body weights, and bacterial burdens consistently demonstrated that treatment with ceftobiprole medocaril is efficacious against otherwise fatal cases of pneumonic tularemia in the rat model.

8.
Infect Immun ; 80(1): 298-310, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22064715

RESUMO

The objective of this study was to characterize the rhesus macaque (RM) as a model for inhalational brucellosis in support of the U.S. Food and Drug Administration's (FDA) Animal Rule. The pathophysiology of chronic Brucella melitensis aerosol infection was monitored in two phases that each occurred over an 8-week time period; dose escalation (8 RMs; targeted doses of 5.0E+03, 5.0E+04, or 5.0E+05 CFU/animal or the unchallenged control) and natural history (12 RMs; targeted dose of 2.50E+05 CFU/animal or the unchallenged control). RMs given an aerosol challenge with B. melitensis developed undulating fevers (6/6 phase I; 8/9 phase II), positive enriched blood cultures (5/10; phase II), and bacterial burdens in tissues starting 14 to 21 days postchallenge (6/6 phase I; 10/10 phase II). In addition, 80% (8/10; phase II) of infected RMs seroconverted 14 to 21 days postchallenge. RMs developed elevations in certain liver enzymes and had an increased inflammatory response by 3 weeks postchallenge as shown by increases in C-reactive protein (6/8) and neopterin (4/8), which correlated with the onset of a fever. As early as 14 days postchallenge, positive liver biopsy specimens were detected (2/8), and ultrasound imaging showed the development of splenomegaly. Finally, histopathologic examination found lesions attributed to Brucella infection in the liver, kidney, lung, and/or spleen of all animals. The disease progression observed with the RMs in this study is analogous to human brucellosis pathophysiology. Thus, the results from this study support the use of the RM as an animal model for inhalational brucellosis to evaluate the efficacy of novel vaccines and therapeutics against B. melitensis.


Assuntos
Brucella melitensis/patogenicidade , Brucelose/patologia , Brucelose/fisiopatologia , Exposição por Inalação , Doenças dos Primatas/patologia , Doenças dos Primatas/fisiopatologia , Estruturas Animais/microbiologia , Estruturas Animais/patologia , Animais , Carga Bacteriana , Proteína C-Reativa/análise , Modelos Animais de Doenças , Enzimas/sangue , Feminino , Febre/microbiologia , Histocitoquímica , Fígado/enzimologia , Fígado/patologia , Testes de Função Hepática , Macaca mulatta , Masculino , Esplenomegalia/diagnóstico , Fatores de Tempo , Estados Unidos , United States Food and Drug Administration
9.
Am J Respir Cell Mol Biol ; 41(2): 226-36, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19131640

RESUMO

The etiology of acute lung injury is complex and associated with numerous, chemically diverse precipitating factors. During acute lung injury in mice, one key event is epithelial cell injury that leads to reduced surfactant biosynthesis. We have previously reported that transgenic mice that express transforming growth factor alpha (TGFA) in the lung were protected during nickel-induced lung injury. Here, we find that the mechanism by which TGFA imparts protection includes maintenance of surfactant-associated protein B (SFTPB) transcript levels and epidermal growth factor receptor-dependent signaling in distal pulmonary epithelial cells. This protection is complex and not accompanied by a diminution in inflammatory mediator transcripts or additional stimulation of antioxidant transcripts. In mouse lung epithelial (MLE-15) cells, microarray analysis demonstrated that nickel increased transcripts of genes enriched in MTF1, E2F-1, and AP-2 transcription factor-binding sites and decreased transcripts of genes enriched in AP-1-binding sites. Nickel also increased Jun transcript and DNA-binding activity, but decreased SFTPB transcript. Expression of SFTPB under the control of a doxycycline-sensitive promoter increased survival during nickel-induced injury as compared with control mice. Together, these findings support the idea that maintenance of SFTPB expression is critical to survival during acute lung injury.


Assuntos
Lesão Pulmonar Aguda/induzido quimicamente , Níquel/toxicidade , Proteína B Associada a Surfactante Pulmonar/metabolismo , Administração por Inalação , Aerossóis , Animais , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Proteína B Associada a Surfactante Pulmonar/genética , Mucosa Respiratória/citologia , Taxa de Sobrevida , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Fator de Crescimento Transformador alfa/genética , Fator de Crescimento Transformador alfa/metabolismo
10.
Clin Vaccine Immunol ; 19(9): 1517-25, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22837095

RESUMO

The development of an appropriate animal therapeutic model is essential to assess the potential efficacy of therapeutics for use in the event of a Bacillus anthracis exposure. We conducted a natural history study that showed New Zealand White rabbits exhibited a significant increase in body temperature (SIBT), changes in hematologic parameters, and increases in C-reactive protein and succumbed to disease with an average time to death of approximately 73 h following aerosol challenge with B. anthracis Ames spores. The SIBT was used as a trigger to treat with a fully human monoclonal antibody directed at protective antigen (PA). Ninety percent (9/10) of the treated rabbits survived the lethal inhalational challenge of B. anthracis. Further characterization investigated the protective window of opportunity for anti-PA antibody administration up to 12 h post-onset of SIBT. Eighty-three percent (5/6) of the rabbits treated at SIBT and 100% (6/6) of those treated at 6 h after SIBT survived challenge. Only 67% (4/6) of the rabbits treated at 12 h after SIBT survived. The increase in body temperature corresponded with both bacteremia and antigenemia (PA in the blood), indicating that SIBT is a suitable trigger to initiate treatment in a therapeutic model of inhalational anthrax.


Assuntos
Antraz/patologia , Antraz/terapia , Bacillus anthracis/patogenicidade , Biomarcadores , Febre/diagnóstico , Animais , Anticorpos Antibacterianos/administração & dosagem , Anticorpos Monoclonais/administração & dosagem , Antígenos de Bactérias , Toxinas Bacterianas/antagonistas & inibidores , Células Sanguíneas/fisiologia , Proteína C-Reativa/análise , Modelos Animais de Doenças , Feminino , Imunoterapia/métodos , Masculino , Coelhos , Análise de Sobrevida , Fatores de Tempo
11.
Clin Vaccine Immunol ; 19(11): 1765-75, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22956657

RESUMO

Appropriate animal models are required to test medical countermeasures to bioterrorist threats. To that end, we characterized a nonhuman primate (NHP) inhalational anthrax therapeutic model for use in testing anthrax therapeutic medical countermeasures according to the U.S. Food and Drug Administration Animal Rule. A clinical profile was recorded for each NHP exposed to a lethal dose of Bacillus anthracis Ames spores. Specific diagnostic parameters were detected relatively early in disease progression, i.e., by blood culture (∼37 h postchallenge) and the presence of circulating protective antigen (PA) detected by electrochemiluminescence (ECL) ∼38 h postchallenge, whereas nonspecific clinical signs of disease, i.e., changes in body temperature, hematologic parameters (ca. 52 to 66 h), and clinical observations, were delayed. To determine whether the presentation of antigenemia (PA in the blood) was an appropriate trigger for therapeutic intervention, a monoclonal antibody specific for PA was administered to 12 additional animals after the circulating levels of PA were detected by ECL. Seventy-five percent of the monoclonal antibody-treated animals survived compared to 17% of the untreated controls, suggesting that intervention at the onset of antigenemia is an appropriate treatment trigger for this model. Moreover, the onset of antigenemia correlated with bacteremia, and NHPs were treated in a therapeutic manner. Interestingly, brain lesions were observed by histopathology in the treated nonsurviving animals, whereas this observation was absent from 90% of the nonsurviving untreated animals. Our results support the use of the cynomolgus macaque as an appropriate therapeutic animal model for assessing the efficacy of medical countermeasures developed against anthrax when administered after a confirmation of infection.


Assuntos
Antraz/patologia , Antraz/terapia , Modelos Animais de Doenças , Doenças dos Primatas/patologia , Doenças dos Primatas/terapia , Infecções Respiratórias/patologia , Infecções Respiratórias/terapia , Animais , Antraz/diagnóstico , Anticorpos Antibacterianos/administração & dosagem , Anticorpos Monoclonais/administração & dosagem , Antígenos de Bactérias/sangue , Toxinas Bacterianas/sangue , Biomarcadores/sangue , Encéfalo/patologia , Feminino , Fidelidade a Diretrizes , Macaca fascicularis , Masculino , Doenças dos Primatas/diagnóstico , Infecções Respiratórias/diagnóstico , Análise de Sobrevida , Fatores de Tempo , Estados Unidos , United States Food and Drug Administration
12.
Sci Rep ; 2: 495, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22773944

RESUMO

To characterize the clinical presentation and pathophysiology of inhalational brucellosis, Balb/c mice were challenged with Brucella melitensis 16M in a nose-only aerosol exposure chamber. A low dose of 1000 cfu/animal of B. melitensis resulted in 45% of mice with tissue burdens eight weeks post-challenge. The natural history of brucellosis in mice challenged by higher aerosol doses was examined by serial euthanizing mice over an eight week period. Higher challenge doses of 1.00E+05 and 5.00E+05 cfu resulted in positive blood cultures 14 days post-challenge and bacterial burdens were observed in the lung, liver and/or spleens 14 days post-challenge. In addition, the progression of brucellosis was similar between mice challenged by the intranasal and aerosol routes. The results from this study support the use of the Balb/c aerosol nose-only brucellosis mouse model for the evaluation of therapeutics against inhalational brucellosis.


Assuntos
Brucella melitensis , Brucelose/microbiologia , Brucelose/patologia , Administração por Inalação , Administração Intranasal , Animais , Temperatura Corporal , Brucella melitensis/patogenicidade , Modelos Animais de Doenças , Feminino , Testes Hematológicos , Fígado/microbiologia , Fígado/patologia , Pulmão/microbiologia , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Baço/microbiologia , Baço/patologia
13.
J Immunol ; 180(12): 7847-58, 2008 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-18523248

RESUMO

The pulmonary innate immune system responds to various airborne microbes. Although its specificity is broad and based on the recognition of pathogen-associated molecular patterns, it is uniquely regulated to limit inflammation and thereby prevent damage to the gas-exchanging alveoli. Macrophages, critical cell determinants of this system, recognize microbes through pattern recognition receptors such as TLRs, which typically mediate proinflammatory responses. The lung collectin, surfactant protein A (SP-A), has emerged as an important innate immune determinant that regulates microbe-macrophage interactions in this environment. In this study, we report the basal and SP-A-induced transcriptional and posttranslational regulation of TLR2 and TLR4 expression during the differentiation of primary human monocytes into macrophages. Despite SP-A's ability to up-regulate TLR2 expression on human macrophages, it dampens TLR2 and TLR4 signaling in these cells. SP-A decreases the phosphorylation of IkappaBalpha, a key regulator of NF-kappaB activity, and nuclear translocation of p65 which result in diminished TNF-alpha secretion in response to TLR ligands. SP-A also reduces the phosphorylation of TLR signaling proteins upstream of NF-kappaB, including members of the MAPK family. Finally, we report for the first time that SP-A decreases the phosphorylation of Akt, a major cell regulator of NF-kappaB and potentially MAPKs. These data identify a critical role for SP-A in modulating the lung inflammatory response by regulating macrophage TLR activity.


Assuntos
Macrófagos Alveolares/imunologia , Macrófagos Alveolares/metabolismo , Proteína A Associada a Surfactante Pulmonar/fisiologia , Receptores Toll-Like/biossíntese , Receptores Toll-Like/genética , Adulto , Diferenciação Celular/imunologia , Membrana Celular/imunologia , Membrana Celular/metabolismo , Células Cultivadas , Humanos , Líquido Intracelular/imunologia , Líquido Intracelular/metabolismo , Macrófagos Alveolares/citologia , Modelos Imunológicos , Monócitos/citologia , Monócitos/imunologia , Monócitos/metabolismo , Ligação Proteica/imunologia , Proteína A Associada a Surfactante Pulmonar/biossíntese , Proteína A Associada a Surfactante Pulmonar/genética , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/biossíntese , Receptor 2 Toll-Like/antagonistas & inibidores , Receptor 2 Toll-Like/biossíntese , Receptor 2 Toll-Like/metabolismo , Receptor 2 Toll-Like/fisiologia , Receptor 4 Toll-Like/biossíntese , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , Receptor 4 Toll-Like/fisiologia , Receptores Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima/imunologia
14.
Am J Respir Cell Mol Biol ; 34(1): 73-82, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16166738

RESUMO

Often fatal, acute lung injury has a complicated etiology. Previous studies from our laboratory in mice have demonstrated that survival during acute lung injury is a complex trait governed by multiple loci. We also found that the increase in metallothionein (MT) is one of the greatest noted in transcriptome-wide analyses of gene expression. To assess the role of MT in nickel-induced acute lung injury, the survival of Mt-transgenic, Mt1/2(+/+), and Mt1/2(-/-) mice was compared. Pulmonary inflammation and global gene expression were compared in Mt1/2(+/+) and Mt1/2(-/-) mice. Gene-targeted Mt1/2(-/-) mice were more susceptible than Mt1/2(+/+) mice to nickel-induced inflammation, surfactant-associated protein B transcript loss, and lethality. Similarly, Mt-transgenic mice exhibited increased survival. MAPPFinder analyses also noted significant decreases in genes involved in protein processing (e.g., ubiquitination, folding), which were greater in Mt1/2(-/-) mice as compared with Mt1/2(+/+) mice early in the progression of acute lung injury, possibly due to a zinc-mediated transcript destabilization. In contrast, transcript levels of genes associated with the inflammatory response, extracellular matrix regulation, and coagulation/fibrinolysis were increased more in Mt1/2(-/-) mice as compared with Mt1/2(+/+) mice late in the development of acute lung injury. Thus, MT ultimately improves survival in the progression of acute lung injury in mice. Transcriptome-wide analysis suggests that this survival may be mediated through changes in the destabilization of transcripts associated with protein processing, the subsequent augmentation of transcripts controlling inflammation, extracellular matrix regulation, coagulation/fibrinolysis, and disruption of surfactant homeostasis.


Assuntos
Metalotioneína/metabolismo , Síndrome do Desconforto Respiratório/genética , Síndrome do Desconforto Respiratório/fisiopatologia , Animais , Progressão da Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Metalotioneína/genética , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Níquel/toxicidade , Análise de Sequência com Séries de Oligonucleotídeos , Síndrome do Desconforto Respiratório/induzido quimicamente , Síndrome do Desconforto Respiratório/metabolismo , Taxa de Sobrevida
15.
Am J Respir Crit Care Med ; 172(11): 1399-411, 2005 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-16100012

RESUMO

RATIONALE: Acute lung injury can occur from multiple causes, resulting in high mortality. The pathophysiology of nickel-induced acute lung injury in mice is remarkably complex, and the molecular mechanisms are uncertain. OBJECTIVES: To integrate molecular pathways and investigate the role of transforming growth factor beta (TGF-beta) in acute lung injury in mice. METHODS: cDNA microarray analyses were used to identify lung gene expression changes after nickel exposure. MAPPFinder analysis of the microarray data was used to determine significantly altered molecular pathways. TGF-beta1 protein in bronchoalveolar lavage fluid, as well as the effect of inhibition of TGF-beta, was assessed in nickel-exposed mice. The effect of TGF-beta on surfactant-associated protein B (Sftpb) promoter activity was measured in mouse lung epithelial cells. MEASUREMENTS AND MAIN RESULTS: Genes that decreased the most after nickel exposure play important roles in lung fluid absorption or surfactant and phospholipid synthesis, and genes that increased the most were involved in TGF-beta signaling. MAPPFinder analysis further established TGF-beta signaling to be significantly altered. TGF-beta-inducible genes involved in the regulation of extracellular matrix function and fibrinolysis were significantly increased after nickel exposure, and TGF-beta1 protein was also increased in the lavage fluid. Pharmacologic inhibition of TGF-beta attenuated nickel-induced protein in bronchoalveolar lavage. In addition, treatment with TGF-beta1 dose-dependently repressed Sftpb promoter activity in vitro, and a novel TGF-beta-responsive region in the Sftpb promoter was identified. CONCLUSIONS: These data suggest that TGF-beta acts as a central mediator of acute lung injury through the alteration of several different molecular pathways.


Assuntos
Expressão Gênica , Proteína B Associada a Surfactante Pulmonar/genética , RNA/genética , Síndrome do Desconforto Respiratório/genética , Fator de Crescimento Transformador beta/metabolismo , Animais , Líquido da Lavagem Broncoalveolar/química , Células Cultivadas , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Fibrinólise/efeitos dos fármacos , Fibrinólise/genética , Camundongos , Níquel/toxicidade , Análise de Sequência com Séries de Oligonucleotídeos , Proteína B Associada a Surfactante Pulmonar/metabolismo , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/metabolismo , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fator de Crescimento Transformador beta/antagonistas & inibidores , Fator de Crescimento Transformador beta/uso terapêutico , Fator de Crescimento Transformador beta1
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