Background. Toll-like receptors (TLRs) play a role in the pathophysiology of sepsis and multiple organ failure. This study examined the effect of CpG oligodeoxynucleotide (CpG-ODN), the TLR9 ligand, on polymicrobial sepsis-induced cardiac dysfunction.Methods. Male C57BL/6 mice were treated with CpG-ODN, control CpG-ODN (control-ODN), or inhibitory CpG-ODN (iCpG-ODN) 1 hour prior to cecal ligation and puncture (CLP)-induced sepsis. Mice that underwent sham surgery served as sham controls. Cardiac function was examined by echocardiography before and 6 hours after CLP.Results. Cardiac function was significantly decreased 6 hours after CLP. CpG-ODN prevented CLP-induced cardiac dysfunction, as evidenced by maintenance of the ejection fraction and fractional shortening. Control-ODN or iCpG-ODN did not alter CLP-induced cardiac dysfunction. CpG-ODN significantly attenuated CLP-induced myocardial apoptosis and increased myocardial Akt and extracellular-signal-related kinase (ERK) phosphorylation levels following CLP. In vitro experiments demonstrated that CpG-ODN promotes an association between TLR9 and Ras, resulting in Akt and ERK phosphorylation. Inhibition of phosphoinositide 3-kinase (PI3K) by Ly294002 or inhibition of ERK by U0126 in vivo abolished CpG-ODN attenuation of CLP-induced cardiac dysfunction.Conclusions. CpG-ODN prevents CLP-induced cardiac dysfunction, in part through activation of PI3K/Akt and ERK signaling. Modulation of TLR9 could be an effective approach for treatment of cardiovascular dysfunction in patients with sepsis or septic shock.

Background. Toll-like receptors (TLRs) play a role in the pathophysiology of sepsis and multiple organ failure. This study examined the effect of CpG oligodeoxynucleotide (CpG-ODN), the TLR9 ligand, on polymicrobial sepsis-induced cardiac dysfunction.Methods. Male C57BL/6 mice were treated with CpG-ODN, control CpG-ODN (control-ODN), or inhibitory CpG-ODN (iCpG-ODN) 1 hour prior to cecal ligation and puncture (CLP)-induced sepsis. Mice that underwent sham surgery served as sham controls. Cardiac function was examined by echocardiography before and 6 hours after CLP.Results. Cardiac function was significantly decreased 6 hours after CLP. CpG-ODN prevented CLP-induced cardiac dysfunction, as evidenced by maintenance of the ejection fraction and fractional shortening. Control-ODN or iCpG-ODN did not alter CLP-induced cardiac dysfunction. CpG-ODN significantly attenuated CLP-induced myocardial apoptosis and increased myocardial Akt and extracellular-signal-related kinase (ERK) phosphorylation levels following CLP. In vitro experiments demonstrated that CpG-ODN promotes an association between TLR9 and Ras, resulting in Akt and ERK phosphorylation. Inhibition of phosphoinositide 3-kinase (PI3K) by Ly294002 or inhibition of ERK by U0126 in vivo abolished CpG-ODN attenuation of CLP-induced cardiac dysfunction.Conclusions. CpG-ODN prevents CLP-induced cardiac dysfunction, in part through activation of PI3K/Akt and ERK signaling. Modulation of TLR9 could be an effective approach for treatment of cardiovascular dysfunction in patients with sepsis or septic shock.

No description available.

Chez la souris, la thérapie anti-HER2 est dépendante de la présence de cellules T CD8+IFN-γ+ et des réponses IFN de type I. Ces IFN sont induits par les TLRs suite à la reconnaissance de signaux de danger, appelés PAMPs et DAMPs. Les TLR-3 et TLR-9 sont tous deux de bons inducteurs d’IFN de type I et sont également capable d’agir en synergie afin d’augmenter les niveaux d’IFN-γ, de TNF-α et d’IL-12. Notre hypothèse fut que la stimulation de ces deux TLRs mènerait à l’amélioration de l’activité anti-tumorale du trastuzumab via le recrutement et l’activation des cellules immunitaires. Nos buts furent de confirmer le potentiel thérapeutique de la combinaison de l’anticorps anti-HER2, de l’agoniste de TLR-3, le poly(I:C), et de l’agoniste de TLR-9, le CpG ODN. Des études in vivo et in vitro nous ont permis de découvrir une synergie entre ces agents qui résulte en une cytotoxicité ciblée plus efficace. De plus, cette thérapie s’avéra efficace chez des modèles CD8-dépendants et CD8-indépendents. Les souris purent rejeter leur tumeur et demeurer sains plusieurs semaines après l’arrêt des injections. Ces souris étaient également protégées lors d’un challenge, soulignant ainsi la présence d’une immunité mémoire. Nous avons aussi découvert que l’administration combine de trastuzumab des deux agonistes de TLRs mène à des réponses systémiques. Des études de déplétion confirmèrent que les cellules T CD8+ sont cruciales pour la protection à long terme des animaux, mais que les pDC sont moins impliquées que ce que l’on pourrait croire. Leur absence n’a que modestement affecté les effets de notre thérapie. À l’opposé, les cellules NK sont d’importants médiateurs des effets thérapeutiques. Des expériences d’ADCC ont révélé que le CpG ODN et poly(I:C) ont tous deux la capacité d’améliorer les fonctions des cellules NK, mais que la stimulation simultanée des TLR-3 et TLR-9 permet de maximiser les effets bénéfiques du trastuzumab. De la même manière, l’addition de CpG ODN et de poly(I:C) aux anticorps anti-HER2 a permis d’augmenter les réponses pro-inflammatoires, plus spécifiquement l’IFN-γ, le TNF-α, l’IP-10 et l’IL-12. / In murine models, anti-HER2 therapy has been shown to be dependent on IFN-γ-producing CD8+ T cells and type I IFN responses. These IFN are induced by TLRs following the recognition of danger signals, called PAMPs or DAMPs. Both TLR-3 and TLR-9 are well known inducers of type I IFN and were also shown to act synergistically to enhance the levels of IFN-γ, TNF-α, and IL-12. Our hypothesis thus was that the stimulation of those two TLRs would lead to an enhancement of the activity of trastuzumab against tumor cells by the recruitment and activation of immune cells. Our goals were to assess the potential therapeutic effects of a combination of anti-HER2 mAbs, TLR-3 agonist poly(I:C) and TLR-9 agonist CpG ODN. In vivo and in vitro studies enabled us to discover a synergy between all agents resulting in a more efficient targeted cytotoxicity. Moreover, this therapy was fully effective in a CD8-dependant cell line as well as a CD8-independent one. Mice were able to completely reject their tumor and remain tumor-free weeks after the injections. Those mice were also protected against a rechallenge, thus underlining the presence of an immune memory. We also discovered that the combined administration of trastuzumab and the TLR agonists leads to systemic responses. Depleting studies confirmed that T CD8+ cells are crucial for the animal to remain tumor-free on the long term, but that pDC are far less involved than what we could have thought. Their absence only modestly affected the outcome of our therapy. On the counterpart, NK cells were important mediators of the therapeutic effect. ADCC assays revealed that both CpG ODN and poly(I:C) are able to enhance the functions of NK cells, but that simultaneous stimulation of the TLR-3 and TLR-9 allows to maximize the beneficial effects of trastuzumab. The same way, the addition of both CpG ODN and poly(I:C) to the anti-HER2 mAbs further enhanced pro-inflammatory responses, more specifically IFN-γ, TNF-α, IP-10 and IL-12.

Innate immune and inflammatory responses contribute to myocardial and cerebral ischemia/reperfusion (I/R) injury. Toll-like receptors (TLRs) play a critical role in the induction of innate immune and inflammatory responses via activation of nuclear factor kappa B (NF-κB). We have shown that activation of NF-κB contributes to myocardial and cerebral I/R injury. Indeed, inhibition of TLR4-mediated NF-κB activation significantly decreased myocardial and cerebral I/R injury via activation of PI3K/Akt signaling. PI3K/Akt signaling is an important pathway in regulating cellular survival and inflammatory responses. Therefore, an important question is how to differentially modulate PI3K/Akt signaling and TLR/NF-κB-mediated signaling pathway during I/R injury? We demonstrated that pretreatment of mice with Pam3CSK4, a specific TLR2 ligand, significantly decreased cerebral I/R injury and improved neuronal functional recovery. Importantly, therapeutic administration of Pam3CSK4 also markedly decreased cerebral I/R injury. The mechanisms involved suppression of NF-κB binding activity and activation of PI3K/Akt signaling. We also demonstrated that CpG-ODN, a specific TLR9 ligand, induced protection against cerebral I/R injury via activation of PI3K/Akt signaling. Our findings were consistent with our previous reports showing that administration of Pam3CSK4 or CpG-ODN protected against myocardial I/R injury via a PI3K/Akt-dependent mechanism. In addition, we demonstrated for the first time that TLR3 located in endosomes played a deleterious role in myocardial I/R injury via activation of NF-κB. To investigate how to activate PI3K/Akt signaling during I/R injury, we examined the role of microRNA (miRs) in regulating PI3K/Akt signaling during myocardial ischemic injury. We discovered that Pam3CSK4 or CpG-ODN treatment significantly increased the expression of miR-130a in the myocardium, while myocardial infarction markedly decreased the levels of miR-130a in the myocardium. The data indicated that miR-130a served a protective role in myocardial ischemic injury. Indeed, we demonstrated for the first time that increased expression of miR-130a significantly attenuated cardiac dysfunction and promoted angiogenesis after myocardial infarction. The mechanisms involved activation of PI3K/Akt signaling via targeting PTEN expression by microRNA-130a. This dissertation discovers novel mechanisms of cerebral and myocardial ischemic injury and provides solid basis for developing new approaches for the treatment and management of stroke and heart attack patients.

Submitted by Anderson Silva (avargas@icict.fiocruz.br) on 2012-07-03T13:19:38Z No. of bitstreams: 1 gentil_albm_vasconcelos_ioc_bp_0030_2010.pdf: 9991419 bytes, checksum: ff93bb9ddf2ae74880f704154a095f8a (MD5) / Made available in DSpace on 2012-07-03T13:19:38Z (GMT). No. of bitstreams: 1 gentil_albm_vasconcelos_ioc_bp_0030_2010.pdf: 9991419 bytes, checksum: ff93bb9ddf2ae74880f704154a095f8a (MD5) Previous issue date: 2010 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / O interesse da literatura científica pela imunoglobulina Y (IgY) é crescente devido a várias vantagens tais como: fácil obtenção, baixo custo, produção em larga escala e método mais adequado quanto ao aspecto bioético. A IgY esta presente em aves e répteis, sendo transferida do soro para a gema dos ovos desses animais através de processo secretório. A produção de imunoglobulina IgY específica contra o vírus da hepatite A se justifica na detecção do vírus da Hepatite A (HAV) em tecido hepático em casos de hepatite fulminante sem diagnóstico definido, em ensaios experimentais para preparação de novas vacinas para hepatite A e a possibilidade de emprego como imunoterapia na prevenção da hepatite aguda pós-exposição ao vírus. Cabe ressaltar que anticorpos anti-HAV atualmente comercializados têm baixa afinidade e têm custo elevado. Nosso estudo consistiu em produzir anticorpos específicos anti-HAV em frangas ISA Brown imunizadas e avaliar seu uso no diagnóstico da hepatite A em tecido. METODOLOGIA: Vinte galinhas divididas em cinco grupos (I-V) foram imunizadas com os seguintes inóculos: Grupo I – Vacina comercial contra hepatite A e Oligodesoxinucleotídeos contendo C-fosfato- guanosina (CpG-ODN); Grupo II – Vacina comercial contra hepatite A; Grupo III – Vírus da Hepatite A, adjuvante incompleto de Freund (IFA) e CpG-ODN; Grupo IV – Vírus da Hepatite A e IFA; Grupo V – IFA (controle). Os ovos foram coletados e purificados pelo método de precipitação em polietileno glicol (PEG). A IgY foi caracterizada e quantificada pelos métodos de ELISA, neutralização in vitro, eletroforese e “Western Blotting”. A detecção do HAV em fígado foi realizada pelo método de imunofluorescência indireta (IIF) com a IgY anti-HAV sendo utilizada como anticorpo primário e IgG de cabra anti-IgY marcada com Alexa Fluor® 488 como anticorpo secundário. Para isto utilizamos amostras de fígado de primatas não-humanos (macacos cynomolgus) infectados e não infectados com HAV, uma amostra humana com hepatite fulminante de etiologia viral por hepatite A e uma amostra humana com hepatite fulminante de etiologia não viral (controle). Os anticorpos primários (IgY) utilizados foram purificados dos ovos dos grupos I e III, e o anticorpo do Grupo V foi utilizado como controle. RESULTADOS E DISCUSSÃO: Todas as aves imunizadas com antígeno HAV soro-converteram, e os anticorpos IgY anti-HAV foram efetivamente transferidos para a gema dos ovos tendo a associação dos adjuvantes IFA mais CPG-ODN se mostrado mais efetiva. Os métodos de caracterização da IgY demonstraram especificidade ao antígeno HAV, contudo o diagnóstico tecidual pela técnica da IIF apresentou excessiva marcação inespecífica, necessitando de aprimoramento na técnica de purificação da imunoglobulina para uso nesta finalidade. / Immunoglobulin Y (IgY) is found in birds and reptiles, currently used by the advantage of being transported from serum to the yolk of eggs of these animals. This protein is purified from egg yolk of immunized birds with a specific antigen, and the IgY easily accessible and has bioethical character, because the animals do not suffer any injury. Besides low cost, the amount of immunoglobulin produced by animals is very high, accounting for five to ten times the average annual production of IgG in rabbits. Moreover, the conserved mammalian proteins are often more immunogenic in birds than in mammals. Detection of Hepatitis A Virus (HAV) in liver tissue is important in cases of acute liver failure to precisely diagnose the cause of liver failure, in clinical trials to test a new vaccine for hepatitis A, and the possibility of employment as immunotherapy in the prevention of acute hepatitis after exposure to the virus. The anti-HAV antibodies currently marketed have low affinity and have high cost. Our study aims to produce specific anti-HAV in laying hens immunized for detection of HAV in liver. METHODS: Twenty chickens divided into five groups (I-V) were immunized with the following schedule: Group I - commercial vaccine against hepatitis A and C-phosphate-guanosine-oligodeoxynucleotide (CpG-ODN); Group II - commercial vaccine against hepatitis A; Group III - HAV, Freund's incomplete adjuvant (IFA) and CpG-ODN; Group IV - HAV and IFA; Group V - IFA (control). The eggs were collected and purified by the method of precipitation in polyethylene glycol (PEG). The IgY was characterized and quantified by ELISA, neutralization, electrophoresis and Western blotting. The detection of HAV in liver were analyzed by indirect immunofluorescence (IIF) with IgY anti-HAV was used as primary antibody and goat IgG anti-IgY labeled with Alexa Fluor® 488 as secondary antibody. We used samples of liver non-human primates (cynomolgus monkeys) infected and not infected with HAV, a human sample with fulminant hepatitis of viral hepatitis A and a human sample with fulminant hepatitis without viral etiology (control). The primary antibodies (IgY) used were purified from eggs of groups I and III, and the antibody of the Group V was used as control. RESULTS AND DISCUSSION: All immunized chickens were seroconvert, except the birds in the control group, and the protein purified from egg yolk IgY was the anti-HAV. All tissue sections showed staining with IgY anti-HAV independent of the liver is infected or not, while control IgY did not show labeling. In all immunofluorescence was background. The IgY group I had better results than group III, having less unspecific binding. These results demonstrate that the antibody produced is really specific for hepatitis A virus and after that the technique can be standardized, it can be used for the immunofluorescence detection of the virus in sections of liver.