A dieta intermitente (DI) estimula mecanismos de defesa do organismo, tornando-o mais resistente a estímulos tóxicos. A DI parece atuar em vias associadas à resposta inflamatória, autofagia, sobrevivência celular e aumenta a resistência contra estresse oxidativo. No entanto, pouco se sabe sobre o papel dos receptores TLR4 e TLR2 nos efeitos da DI. Este trabalho avaliou a influência do TLR4 e TLR2 nos efeitos da DI sobre a memória e a sinalização associada aos fatores de transcrição NF-κB, NRF2 e FOXO em camundongos nocaute para TLR4 ou TLR2. Os resultados sugerem que o TLR4 e TLR2 participam da modulação pela DI dos níveis de estresse oxidativo, biomarcadores periféricos e do NF-κB, CREB, AP1, NRF2, além das proteínas moduladas por esses fatores de transcrição como o BDNF, HO1, enzimas antioxidantes, chaperonas e citocinas. Esses resultados permitem um maior entendimento dos processos fisiológicos que visam o desenvolvimento de novas intervenções farmacológicas para a promoção da longevidade, envelhecimento saudável e o tratamento de distúrbios neurodegenerativos. / Intermittent fasting (IF) stimulates the body\'s defense mechanisms, making it more resistant to toxic stimuli. IF seems to act by mechanisms associated with cell survival, autophagy, inflammation and enhancing oxidative stress resistance, thereby involving the modulation of transcription factors. However, little is known about the involvement of TLR4 and TLR2 on IF effects. The present work investigated the influence of TLR2 and TLR4 on IF effects on memory and on signaling mechanisms associated with the transcription factors NF-κB, NRF2 and FOXO in TLR2 KO or TLR4 KO mice. The results suggest that TLR4 and TLR2 participate in the effects of IF on oxidative stress levels, peripheral biomarkers, and on NF-κB, CREB, AP1 and NRF2, as well as proteins modulated by these transcription factors such as BDNF, HO1, antioxidant enzymes, chaperones and cytokines. These results allow a better understanding of physiological processes that aim at developing new pharmacological interventions to promote longevity, healthy aging, and the treatment of neurodegenerative disorders.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-03-26T13:52:57Z No. of bitstreams: 2 Tese - Delson Jose da Silva - 2014.pdf: 4417980 bytes, checksum: 09ba5f6cc0d7b39ded36ffee59e305f4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-03-26T15:48:14Z (GMT) No. of bitstreams: 2 Tese - Delson Jose da Silva - 2014.pdf: 4417980 bytes, checksum: 09ba5f6cc0d7b39ded36ffee59e305f4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-26T15:48:14Z (GMT). No. of bitstreams: 2 Tese - Delson Jose da Silva - 2014.pdf: 4417980 bytes, checksum: 09ba5f6cc0d7b39ded36ffee59e305f4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-29 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Parkinson’s disease (PD) is as a neurodegenerative disorder caused by neuron loss in the substantia nigra, which produces dopamine. Evidences suggest that several inflammatory cytokines are enhanced in the brain and blood of patients presenting with PD. These cytokines might be induced by Toll-like receptor (TLR) activation. In peripheral blood, monocytes express TLR and may participate in the immunopathogenicity of neurodegenerative diseases. The objectives of this work were: carry out a literature review about neuroinflammation in PD; assess possible alterations in production of inflammatory cytokines in blood cultures of patients presenting with PD activated by TLR agonists; evaluate the percentages of the two main monocyte subpopulations, as well as TLR2 and TLR4 expression in these subpopulations in peripheral blood of patients presenting with PD. Patients presenting with PD (n = 31) and healthy individuals (n = 31), matched by gender and age, were evaluated and the patients were assessed regarding the severity of their neurological and psychiatric symptoms using the Hoen & Yahr scale (H&Y) and the Unified Parkinson’s Disease Rating Scale (UPDRS). Blood cultures were activated with TLR2 agonists (Pam3Cys), TLR4 (LPS), or TLR7/8 (R848). Cytokines (TNF, IL-1β, IL-6, IL-12p70, and IL-10) were Abstract 12 quantified in the serum and supernatant of blood cultures using Cytometer bead array. Monocytes (CD14+CD16– and CD14+CD16+) and TLR2 and TLR4 expression were identified using flow cytometry. Cytokine concentrations in the serum of patients and controls were similar and no significant association was found between cytokine concentrations and UPDRS scores. However, after activation of blood cultures of patients, a significant decreased response to TLR2 (TNF, IL-1β, IL-6, IL-10) and TLR7/8 (IL-6) agonists was observed. No correlation was observed between the concentrations of cytokines induced by TLR2 or TLR7/8 agonists and UPDRS scores. The percentages of monocytes CD14+CD16– and CD14+CD16+ did not significantly differ between patients and controls, and no alterations in TLR2 or TLR4 expressions were detected in these monocyte subpopulations in patients. The results indicate that leukocytes, especially monocytes, of patients presenting with PD show decreased capacity to respond to the activation via TLR2. This decrease may be associated with the previous activation of TLR2 in vivo, making the cells tolerant to new stimuli ex vivo. Assessing the activation of monocytes in peripheral blood, via TLR, may help the evaluation of the neurodegenerative/ neuroinflammatory process in PD, contributing to a better understanding of the pathophysiology of this disease. / A doença de Parkinson (DP) é uma afecção neurodegenerativa que ocorre devido à perda neuronal na substância negra, produtora de dopamina. Evidências sugerem que várias citocinas inflamatórias estão aumentadas no cérebro e no sangue de pacientes com DP. Essas citocinas podem ser induzidas por ativação dos receptores similares a Toll (Toll-like receptors, TLR). No sangue periférico, os monócitos expressam TLR e podem participar na imunopatogenia de doenças neurodegenerativas. Os objetivos deste trabalho foram: realizar uma revisão de literatura sobre neuroinflamação na DP; avaliar possíveis alterações na produção de citocinas inflamatórias em hemoculturas de pacientes com DP ativada por agonistas de TLR; avaliar as porcentagens das duas principais subpopulações de monócitos e a expressão de TLR2 e TLR4 nestas subpopulações no sangue periférico de pacientes com DP. Foram avaliados 31 pacientes com DP e 31 indivíduos sadios, pareados por gênero e idade, sendo os pacientes avaliados quanto à gravidade dos sintomas neurológicos e psiquiátricos utilizando-se as escalas H&Y (Hoen & Yahr scale) e UPDRS (Unified Parkinson’s Disease Rating Scale). As hemoculturas foram ativadas com agonistas de TLR2 (Pam3Cys), TLR4 (LPS) ou TLR7/8 (R848). As citocinas (TNF, IL-1β, IL-6, IL-12p70 e IL-10) foram quantificadas no soro e nos sobrenadantes das culturas utilizando citometria (Cytometer bead array). Os monócitos (CD14+CD16– e CD14+CD16+) e a expressão de TLR2 e TLR4 nestes foram identificados por citometria de fluxo. As concentrações de citocinas nos soros de pacientes e controles foram similares e não houve Resumo 10 associação significativa entre as concentrações das citocinas e os escores da UPDRS. No entanto, após ativação das hemoculturas dos pacientes, foi observada significativa resposta diminuída aos agonistas de TLR2 (TNF, IL- 1β, IL-6, IL-10) e de TLR7/8 (IL-6). Não foi observada correlação entre as concentrações de citocinas induzidas pelos agonistas de TLR2 ou de TLR7/8 e os escores de UPDRS. As porcentagens dos monócitos CD14+CD16– e CD14+CD16+ não diferiram significativamente entre os pacientes e os controles, e não foram detectadas alterações nas expressões de TLR2 ou TLR4 nestas subpopulações de monócitos nos pacientes. Os resultados indicam que os leucócitos, especialmente os monócitos, de pacientes com DP apresentam diminuída capacidade de resposta à ativação via TLR2. Essa diminuição pode estar associada à ativação prévia de TLR2 in vivo, tornando as células tolerantes a novos estímulos ex vivo. Avaliar a ativação de monócitos no sangue periférico, via TLR, pode auxiliar na avaliação do processo neurodegenerativo/neuroinflamatório na DP, contribuindo para a melhor compreensão da patofisiologia desta doença.

Os tecidos periodontais estão em confronto contínuo com microrganismos capazes de disparar mecanismos da resposta imune inata, dando origem ao infiltrado inflamatório neutrofílico. A participação dos receptores tipo Toll (TLRs) na resposta de neutrófilos frente à periodontopatógenos associados à doença periodontal precisam ser determinados. Nesse estudo procuramos caracterizar o infiltrado inflamatório presente no peritônio de animais deficientes de TLR2-/-, avaliar a atividade fagocítica, bem como a produção de óxido nítrico (NO) e a atividade de mieloperoxidase (MPO) no curso da infecção por Aggregatibacter actinomycetemcomitans (Aa). Os resultados revelaram um menor recrutamento de leucócitos para o peritônio de animais deficientes de TLR2 (TLR2-/-), com predomínio de macrófagos no exsudato peritoneal tanto de animais selvagens (WTTLR2-/-) como nos animais nocautes. A análise da atividade fagocítica revelou uma menor taxa de fagocitose pelas células do exsudato de animais TLR2-/- e, ainda, a deficiência do receptor TLR2 inibiu a produção de NO (óxido nítrico) e aatividade de MPO (mieloperoxidase). Adicionalmente, são apresentados os resultados referentes ao protocolo de doença periodontal experimentalmente induzida (DPEI) com Aggregatibacter actinomycetemcomitans (Aa) em camundongos deficientes de TLR2. Os resultados mostraram que 100% dos animais deficientes de TLR2 sobreviveram à infecção durante o período de observação. Em relação à análise de perda óssea os dados revelaram uma maior perda progressiva de osso alveolar na região dos molares de animais deficientes de TLR2. A ausência do receptor interferiu com a disseminação da bactéria, uma vez que se observou um grande número de bacilos no linfonodo e baço dos animais que não expressaram TLR2, diferente do observado para os animais selvagens (WTTLR2-/-). Os resultados indicam a importância da sinalização via TLR2 durante a resposta imune contra Aggregatibacter actinomycetemcomitans. / Polymorphonuclear leukocytes (PMNs) are the first line of defense against bacterial infections. PMNs express a numerous pattern-recognition receptors (PRR) that facilitate identification of invading microorganisms. Toll-like receptors (TLRs) represent the main class of PRR involved to a recognize pathogenic microorganism. However, the role played by TLR-2 in the recognition and killing of Aggregatibacter actinomycentemcomitans by PMNs is unknown. Thus, we investigated the ability of TLR-2 to mediate neutrophil phagocytosis and bactericidal activity. To determine the role of A. actinomycentemcomitans in triggering neutrophil infiltration, TLR2-/- mice were infected intraperitoneally (2x109 bacteria) and sacrificed after 24 hours. Peritoneal inflammatory cells were isolated and analyzed by optical microscopy. Examination of local inflammatory infiltrates revealed that neutrophil influx into peritoneal cavity of TLR2-/- mice was similar than that observed into their littermate controls wild type C57BL/6 mice (WT). A. actinomycentemcomitans was detected in the spleen of the TLR2-/- mice but not in WT. In the phagocytic assays, TLR2-/- presented minor number of ingested inflammatory cells than WT. Peritoneal cells were stimulated with A. actinomycetemcomitans antigens, and NO and myeloperoxidase was measured after 48 hours; results showed that TLR2-/- cells produce less NO and MPO than WT. In addition, TLR2-/- deficient mice presented higher bone loss following oral infection with A. actinomycetemcomitans when compared with WT and higher tissue destruction.

L'organisme est exposé à divers agents infectieux et doit mettre en place une réponse immunitaire adéquate pour se protéger. Mes travaux de thèse m'ont permis d'étudier la réponse innée à l'infection par Listeria monocytogenes (L.m) et l'inflammation pulmonaire induite par la flagelline extraite de Salmonella typhimurium. Mes résultats ont mis en évidence l'association du co-récepteur CD14 avec TLR2 (Toll-like Receptor 2) dans la détection de L.m injectée par voie veineuse. En revanche, CD14 ne semble pas être associé au TLR5 dans la reconnaissance de la flagelline. Par ailleurs, l'activation des TLR par leurs ligands permet la synthèse de cytokines intervenant dans l'inflammation. J'ai ainsi pu étudier plus précisément le TNF (Tumor Necrosis Factor). Cette protéine pro-inflammatoire est un des médiateurs principaux de l'immunité et existe sous une forme membranaire qui a été peu étudiée (Mem-TNF) et sous une forme soluble bien connue (sTNF). Mes études ont montré que ce Mem-TNF active la production de cytokines et de médiateurs chimiques de l'inflammation conférant une protection partielle contre Listéria. L'étude de cette cytokine membranaire nous a permis de tester une nouvelle génération de traitements moins agressifs que les anti-TNF contre l'arthrite rhumatoïde ou la maladie de Crohn.

Submitted by Tatiana Oliveira (tsilva@icict.fiocruz.br) on 2012-06-06T12:07:05Z No. of bitstreams: 1 rosane_b_oliveira_ioc_bp_0007_2003.pdf: 28903576 bytes, checksum: 4167a22455a36ea7147bd41b4dc7b566 (MD5) / Made available in DSpace on 2012-06-06T12:07:05Z (GMT). No. of bitstreams: 1 rosane_b_oliveira_ioc_bp_0007_2003.pdf: 28903576 bytes, checksum: 4167a22455a36ea7147bd41b4dc7b566 (MD5) Previous issue date: 2003 / Fundação Oswaldo Cruz.Instituto Oswaldo Cruz. Rio de janeiro, RJ, Brasil / A principal complicação na hanseníase é o desenvolvimento de deformidades ao longo do curso crônico da doença. Neste estudo, nós utilizamos uma linhagem humana maligna de células de Schwann (ST88-14) para caracterizar a indução do fenômeno de morte celular e a produção de citocinas em células de Schwann (CS) in vivo e in vitro. Têm sido demonstrado que CS tornam-se ativadas e podem produzir citocinas durante injúria experimental e em algumas neuropatias. As funções fisiológicas das células de Schwann e a compreensão de como citocinas, M. leprae e seus componentes causam danos a estas células foram investigados. As células infetadas estimulam a formação do granuloma e subsequentes destruição bacilar e o dano no nervo. A recente descrição dos mecanismos de entrada da bactéria nesta célula e, conseqüentemente, o estudo da interação do M. leprae e da CS no que se refere à resposta imune inata (expressão de receptores Toll - TLR) são essenciais para tentar esclarecer os mecanismos envolvidos no desenvolvimento de lesões do nervo. Assim a expressão do receptor Toll foi avaliado na linhagem ST88-14, em células de Schwann primárias e em biópsias de pele. Investigamos também a possibilidade de células de Schwann humanas serem susceptíveis a morte pela ativação do TLR2. Foi observado a expressão de TLR2 em células de Schwann e a ativaçao destas células com um agonista TLR2, um lipopeptídeo sintético que abrange a porção N-terminal putativa da lipoproteína 19kD de M. leprae induziu a relativa secreção de citocinas IL-6 e IL-8, bem como induziu um aumento no número de células com características de células apoptóticas. A apoptose induzida pelo lipopeptídeo e a produção de citocinas nas CS foi bloqueada com anticorpo monoclonal anti-TLR2. Foi também observado que as CS em lesões de pele de pacientes com hanseníase expressam TLR2 bem como a presença de apoptose in vivo. A capacidade de ligantes de M. leprae induzirem apoptose de CS através de TLR2 proporciona um mecanismo pelo qual a ativação da resposta imune inata contribui para a lesão de nervo na hanseníase. Neste projeto, a capacidade e efeitos de TNFa/TGFb e do M. leprae nas células ST88-14 foram investigados. Neste estudo nós mostramos que as células de Schwann expressam constitutivamente ambos os receptores de TNF. Os resultados demonstraram um índice aumentado de apoptose nas culturas das células na presença de TNFa /TGFb em comparação com controle. Finalmente, um índice aumentado de apoptose também foi observado quando na ST88-14 foi mantida em cultura na presença de M. leprae vivo ou morto. Os dados indicam que TNF-Rs bem como uma resposta específica para TNFa e o efeito sinergístico com TGFb, assim como a infecção pelo M. leprae podem estar implicados na patogênese da lesão do nervo na hanseníase / A major complication in leprosy is the development of deformities along the chronic course of disease. In the present study, a malignant human Schwann cell line (ST88-14) was used to characterize the induction of cell death and the production of cytokines in these in vivo and in vitro SCs. It had previously been shown that, in some neuropathies, SC became activated and produced cytokines during experimental injury. Here, the physiological functions of SC and how cytokines, M. leprae, and M. leprae components possibly cause damage to these cells were investigated. The recent description of the mechanisms utilized by M. leprae to enter SCs and, consequently, the study of M. leprae-SC interaction in the innate immune response (Toll-like receptors - TLR) are essential to understanding what is involved in the development of nerve damage. In this connection, an evaluation was made of TLR expression in skin biopsies and the ST88-14 cell line and whether these cells were susceptible to cell death through TLR2 activation. It was found that TLR2 expression on SCs and their activation by a TLR2 agonist - a synthetic lipopeptide comprising the N-terminal portion of the putative M. leprae 19kD lipoprotein – simultaneously induced IL-6 and IL-8 secretion and triggered increased production of apoptotic cells, which, along with cytokine production, was blocked by an anti-TLR2 monoclonal antibody. Besides demonstrating the presence of TLR2 expression in the SCs of skin lesions of leprosy patients, SCs were also identified in lesions that had undergone apoptosis in vivo. The ability of M. leprae ligands to induce apoptosis of schwann cells through TLR2 provides a mechanism by which activation of the innate immune response contributes to nerve injury in leprosy. Thus, by investigating the capacity and effects of TNFa/TGFb and M. leprae within the human ST88-14 cell line, this study showed that SCs constituitively expressed both TNF receptors and that, in comparison to the controls, their presence triggered increased apoptosis in culture, also observed when ST88-14 was maintained in culture in the presence of live and/or dead M. leprae.. It would, therefore, seem apparent that these observations are clear indications that the TNF-Rs, in conjunction with a specific TNFa response, the synergistic effect with TGFb, and M. leprae infection are all implicated in the pathogenesis of nerve damage

Os tecidos periodontais estão em confronto contínuo com microrganismos capazes de disparar mecanismos da resposta imune inata, dando origem ao infiltrado inflamatório neutrofílico. A participação dos receptores tipo Toll (TLRs) na resposta de neutrófilos frente à periodontopatógenos associados à doença periodontal precisam ser determinados. Nesse estudo procuramos caracterizar o infiltrado inflamatório presente no peritônio de animais deficientes de TLR2-/-, avaliar a atividade fagocítica, bem como a produção de óxido nítrico (NO) e a atividade de mieloperoxidase (MPO) no curso da infecção por Aggregatibacter actinomycetemcomitans (Aa). Os resultados revelaram um menor recrutamento de leucócitos para o peritônio de animais deficientes de TLR2 (TLR2-/-), com predomínio de macrófagos no exsudato peritoneal tanto de animais selvagens (WTTLR2-/-) como nos animais nocautes. A análise da atividade fagocítica revelou uma menor taxa de fagocitose pelas células do exsudato de animais TLR2-/- e, ainda, a deficiência do receptor TLR2 inibiu a produção de NO (óxido nítrico) e aatividade de MPO (mieloperoxidase). Adicionalmente, são apresentados os resultados referentes ao protocolo de doença periodontal experimentalmente induzida (DPEI) com Aggregatibacter actinomycetemcomitans (Aa) em camundongos deficientes de TLR2. Os resultados mostraram que 100% dos animais deficientes de TLR2 sobreviveram à infecção durante o período de observação. Em relação à análise de perda óssea os dados revelaram uma maior perda progressiva de osso alveolar na região dos molares de animais deficientes de TLR2. A ausência do receptor interferiu com a disseminação da bactéria, uma vez que se observou um grande número de bacilos no linfonodo e baço dos animais que não expressaram TLR2, diferente do observado para os animais selvagens (WTTLR2-/-). Os resultados indicam a importância da sinalização via TLR2 durante a resposta imune contra Aggregatibacter actinomycetemcomitans. / Polymorphonuclear leukocytes (PMNs) are the first line of defense against bacterial infections. PMNs express a numerous pattern-recognition receptors (PRR) that facilitate identification of invading microorganisms. Toll-like receptors (TLRs) represent the main class of PRR involved to a recognize pathogenic microorganism. However, the role played by TLR-2 in the recognition and killing of Aggregatibacter actinomycentemcomitans by PMNs is unknown. Thus, we investigated the ability of TLR-2 to mediate neutrophil phagocytosis and bactericidal activity. To determine the role of A. actinomycentemcomitans in triggering neutrophil infiltration, TLR2-/- mice were infected intraperitoneally (2x109 bacteria) and sacrificed after 24 hours. Peritoneal inflammatory cells were isolated and analyzed by optical microscopy. Examination of local inflammatory infiltrates revealed that neutrophil influx into peritoneal cavity of TLR2-/- mice was similar than that observed into their littermate controls wild type C57BL/6 mice (WT). A. actinomycentemcomitans was detected in the spleen of the TLR2-/- mice but not in WT. In the phagocytic assays, TLR2-/- presented minor number of ingested inflammatory cells than WT. Peritoneal cells were stimulated with A. actinomycetemcomitans antigens, and NO and myeloperoxidase was measured after 48 hours; results showed that TLR2-/- cells produce less NO and MPO than WT. In addition, TLR2-/- deficient mice presented higher bone loss following oral infection with A. actinomycetemcomitans when compared with WT and higher tissue destruction.

Stress can enhance or suppress immune functions depending on a variety of factors. Our previous studies observed that Toll-like receptor 2 (TLR2) participates in chronic restraint stress-induced immune dysfunction. However, the mechanism by which TLR2 prevents immune suppression remains elusive. Our investigation found that stimulation of TLR2 by peptidoglycan (PGN) significantly attenuates splenocyte apoptosis and markedly blocks alterations of anti-apoptotic and apoptotic proteins. Activation of TLR2 inhibits chronic stress-reduced phosphorylation of c-Jun N-terminal kinase (JNK) and diminishes chronic stress-induced up-regulation of corticosterone production. Additionally, our data show that chronic stress causes a dramatic decrease of cytokine IL-2 level but an increase of IL-4 and IL-17 in CD4+ T cells. Interestingly, PGN could block these alterations of cytokine levels. Collectively, our studies demonstrate that stimulation of TLR2 attenuates chronic stress-induced immune suppression by modulating apoptosis-related proteins and immunoregulatory agents.

Stress can enhance or suppress immune functions depending on a variety of factors. Our previous studies observed that Toll-like receptor 2 (TLR2) participates in chronic restraint stress-induced immune dysfunction. However, the mechanism by which TLR2 prevents immune suppression remains elusive. Our investigation found that stimulation of TLR2 by peptidoglycan (PGN) significantly attenuates splenocyte apoptosis and markedly blocks alterations of anti-apoptotic and apoptotic proteins. Activation of TLR2 inhibits chronic stress-reduced phosphorylation of c-Jun N-terminal kinase (JNK) and diminishes chronic stress-induced up-regulation of corticosterone production. Additionally, our data show that chronic stress causes a dramatic decrease of cytokine IL-2 level but an increase of IL-4 and IL-17 in CD4+ T cells. Interestingly, PGN could block these alterations of cytokine levels. Collectively, our studies demonstrate that stimulation of TLR2 attenuates chronic stress-induced immune suppression by modulating apoptosis-related proteins and immunoregulatory agents.

Physical and psychological stress can alter the immune system in both humans and animals. Stress is a known risk factor for numerous human diseases, such as infectious and autoimmune diseases, and cancer. Toll-like receptors (TLRs) play a pivotal role in the induction of innate and adaptive immune response. Our previous studies have shown that TLR4 deficiency prevents stress-induced splenocyte reduction. However, the role of TLR2 in stress-mediated lymphocyte reduction is unknown. In this study, we investigated the effects of TLR2 ligands on stress-induced lymphocyte reduction. We also defined whether the phosphoinositide 3-kinases (PI3Ks)/Akt pathway contributes to TLR2-mediated lymphocyte numbers altered by stress. Our data have shown that stimulation of TLR2 by TLR2 ligands peptidoglycan (PGN) or Pam3CSK4 (Pam3) attenuates stress-induced reduction in lymphocyte numbers. However, TLR2 ligand-induced protection from stress-induced lymphocyte reduction is lost in TLR2 deficiency in mice. Furthermore, stimulation of TLR2 by PGN induces protection from stress-induced reduction in the number of splenocytes through PI3K. Moreover, PGN dramatically increases the level of phosphorylation of Akt through a PI3K-dependent manner. Moreover, we found that stimulation of TLR2 by PGN induced protection from stress-induced reduction in splenocyte numbers is abolished in β-arrestin 2 deficient mice. In addition, PGN-induced immune protection in stress-induced changes of cytokine levels appears to require -arrestin 2, a multifunctional adaptor and signal transducer. Collectively, our study thus demonstrates that stimulation of TLR2-mediated PI3K signaling attenuates splenocyte reduction induced by stress, and that β-arrestin 2 modulates TLR2-mediated immune response following stress.

No description available.