Made available in DSpace on 2015-04-14T14:51:18Z (GMT). No. of bitstreams: 1
438527.pdf: 10657738 bytes, checksum: caad3abdc5d9b9863dbe5c3d7120700f (MD5)
Previous issue date: 2012-03-26 / Transplantation of solid organs has emerged as a viable therapeutic modality for the treatment of a variety of disorders. Rejection of solid organ allografts is the result of a complex range of interactions involving coordination between both the innate and adaptive immune system. Therewith, a major goal of clinical organ transplantation is to induce a donor-specific unresponsive state in a mature immune system that is free from long-term immunosuppression and chronic rejection. The limitations in the establishment of immunossupressive stratagies led us to search new methods to the modulation of the homeostatic mechanisms that limit and prevent inflammatory responses in allograft tissue. The heat shock protein 70 (Hsp70) has a protective and antiinflamatory role in several animals models like arthritis, colitis, pulmonary fibrosis and brain injury. This protein can modulates both the innate and adaptative immune system. Our group demonstrated that Mycobacterium tuberculosis Hsp70 (Mt Hsp70) can inhibit bone marrow dendritic cells (BMDCs) maturation; however the mechanisms involved in this process has not been completely elucidated. In the present work, we demonstrated that Mt Hsp70 inhibited the acute rejection in two allograft models (a tumor model and a skin allograft model).In both models, we observed an involvement of Tregs. In addition, s.c. Mt Hsp70 injection leds to an increase in Treg population and IL-10 production in the draining lymph node. We also observed that the inhibition of acute rejection induced by Mt Hsp70 was dependent on the presence of toll-like receptor (TLR) 2 in the allograft, and not in the host. In BMDCs, we demonstrated that IL-10 production induced by Mt Hsp70 is dependent on TLR2. Also, we analyzed the phosphorylation of ERK, p38 and Akt after Mt Hsp70 stimulus. We observed an increase in p-ERK expression, but no difference in p-38 and p-Akt levels. The inhibition of ERK abolished the IL-10 production induced by Mt Hsp70. We propose that Mt Hsp70 effect on DCs can be used as a therapeutic approach in transplantation models. / O transplante de ?rg?os s?lidos emergiu como uma terapia vi?vel para o tratamento de uma variedade de patologias. A rejei??o dos enxertos ? resultado de uma s?rie complexa e coordenada de intera??es envolvendo o sistema imune inato e adaptativo. Com isso, o maior desafio no transplante de ?rg?os s?lidos ? induzir um estado irresponsivo e espec?fico ao doador em um sistema imune maduro sem que haja uma imunossupress?o sist?mica e de longo prazo, tudo isso livre de rejei??o cr?nica. As limita??es no estabelecimento de estrat?gias imunossupressoras nos levaram a buscar novos m?todos para a modula??o dos mecanismos homeost?ticos que previnem e limitam as respostas inflamat?rias nos tecidos enxertados. A prote?na de choque t?rmico (Heat shock protein Hsp) 70 tem um papel antiinflamat?rio e protetor em modelos animais experimentais como artrite, colite, fibrose pulmonar e danos cerebrais. Essa prot?ina pode modular tanto o sistema imune inato quanto o adaptativo. Nosso grupo demonstrou que a Hsp70 de Mycobacterium tuberculosis (Mt Hsp70) pode inibir a matura??o de c?lulas dendr?ticas diferenciadas da medula ?ssea (bone marrow dendritic cells BMDCs), por?m o mecanismo envolvido nesse processo ainda n?o foi totalmente esclarecido. Nesse trabalho, demonstramos que a Mt Hsp70 foi capaz de aumentar a sobrevida do enxerto em dois modelos murinos de transplantes (um modelo tumoral e um modelo de aloenxerto cut?neo).Em ambos os modelos, observamos o envolvimento de Tregs. Demonstramos que a administra??o s.c. da Mt Hsp70 levou a um aumento dessas c?lulas nos linfonodos drenantes, al?m de um aumento na produ??o de IL-10. Tamb?m observamos que a inibi??o da rejei??o aguda induzida pela Mt Hsp70 no modelo de aloenxerto cut?neo ? dependente da presen?a do receptor do tipo toll (toll like receptor TLR) 2 no enxerto, e n?o no receptor. Nas BMDCs, vimos que a indu??o da IL-10 induzida pela Mt Hsp70 ? dependente de TLR2. Ainda nessas c?lulas, analisamos a fosforila??o de mol?culas como a ERK, p38 e Akt ap?s o est?mulo com a Mt Hsp70. Observamos um aumento na express?o de p-ERK e nenhuma altera??o nos n?veis de p-p38 e p-Akt. A inibi??o da ERK aboliu a produ??o de IL-10 induzida pela Mt Hsp70. Propomos que esse efeito da Mt Hsp70 sobre as DCs pode servir como interven??o terap?utica em modelos de transplantes.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5437 |
| Date | 26 March 2012 |
| Creators | Borges, Thiago de Jesus |
| Contributors | Bonorino, Cristina |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
Page generated in 0.002 seconds