[Truncated abstract] Fibrosis is a feature of many pulmonary conditions, including idiopathic pulmonary fibrosis (IPF), which is characterised by the accumulation of fibroblasts/myofibroblasts and excessive deposition of collagen. IPF is a disease of unknown aetiology that is unresponsive to current therapy and is typically fatal. The inflammatory cytokine interleukin (IL)-6 is elevated in patients with IPF and recent studies have shown that IL-6-induced signalling is altered in lung fibroblasts from patients with IPF. IL-6 belongs to the gp130 cytokine family, which is a group of ten structurally related cytokines, that all require the membrane bound glycoprotein gp130 to activate intracellular signalling pathways. Gp130 activates intracellular signalling through the Shp2-ERK1/2 and STAT1/3 pathways to mediate cellular activities. This thesis tests the hypothesis that gp130-mediated signalling is dysregulated in the development and progression of pulmonary fibrosis. To address this hypothesis, I assessed the role of gp130-mediated signalling in a mouse model of bleomycin-induced lung fibrosis. This thesis utilised two novel gp130 mutant mice strains with directed and enhanced gp130-mediated Shp2-ERK1/2 (gp130¿STAT/¿STAT) or STAT1/3 (gp130757F/757F) signalling. I observed complete protection from fibrosis in gp130¿STAT/¿STAT mice up to 60 days after bleomycin treatment and profound fibrosis in gp130757F/757F mice compared to wt controls. The enhanced fibrosis observed in gp130757F/757F mice was diminished by monoallelic deletion of STAT3 (gp130757F/757F;STAT3+/-), identifying gp130-STAT3 signalling as a novel promoter of lung fibrosis. ... In addition, IL-6/11 activation of gp130-mediated signalling modulated transforming growth factor (TGF)-ß-induced effects on adult fibroblast proliferation and myofibroblast differentiation. Interaction between IL-6/11 and TGF-ß1 on fibroblast proliferation was dependent on both the gp130-ERK1/2 and gp130-STAT1/3 pathways. Loss of either pathway abrogated the effects of IL-6 and IL-11 on TGF-ß1- 4 induced fibroblast proliferation. However, it was clear that gp130-STAT3 signalling inhibited TGF-ß1-induced myofibroblast differentiation of primary lung fibroblasts. The inhibition of myofibroblast differentiation was associated with gp130-STAT3 dependent inhibition of TGF-ß1-induced Smad3 phosphorylation. These results indicate that IL-6 and IL-11 promote myofibroblastic differentiation of lung fibroblasts, while gp130-STAT3 signalling inhibits TGF-ß1-induced Smad3 phosphorylation and myofibroblastic differentiation of lung fibroblasts While the pathogenesis of IPF is unknown, it is believed that excessive collagen deposition, aberrant fibroblast behaviour and an inflammatory response are critical to the progression of this disease. It has been shown here that IL-6 family cytokines mediate the development and progression of bleomycin-induced lung fibrosis by increasing collagen synthesis, fibroblast proliferation, myofibroblast differentiation and inflammation through gp130-STAT3 signalling. This thesis has demonstrated that differential activation of cytoplasmic signalling pathways by a membrane bound receptor can have a profound effect on pulmonary responses to injury. Furthermore, this thesis is the first study to identify the gp130-STAT3 pathway as a therapeutic target in the treatment of IPF.

Hyaline cartilage is a highly specialized tissue, which plays an important role in the articulating joints of an individual. It provides the joints with a nearly frictionless, impact resisting surface to protect the ends of the articulating bones. Articular cartilage has a poor self-repair capacity and, therefore, it rarely heals back to normal after an injury. Overweight, injuries, overloading and genetic factors may initiate a degenerative disease of the joint called osteoarthritis. Osteoarthiritis is a major global public health issue. Currently, the most used treatment for large articular cartilage defects is joint replacement surgery. However, possibilities to replace this highly invasive operation with strategies based on tissue engineering are currently investigated. The idea of the tissue engineering is to optimize the use of the cells, biomaterials and culture conditions to regenerate a new functional tissue for the defect site. The goal of this thesis was to manufacture cartilage tissue in cell culture conditions in vitro. Bovine primary chondrocytes isolated from the femoral condyles were used in all the experiments for neocartilage production. The samples were collected for histology, gene expression level quantifications, and analyses of proteoglycan (PG) content and quality. The histological sections were stained for type II collagen and PGs, the quantitative RT-PCR was used to observe the relative expressions of aggrecan, Sox9, procollagen α2(I) and procollagen α1(II) genes. The PGs were quantified using a spectrophotometric method, and agarose gel electrophoresis was used to separate the PGs according to their size. In the two first studies, we optimized the culture conditions of in vitro scaffold-free culture technique to produce the native-type hyaline cartilage of a good quality. We found out that high glucose concentration and hypertonic medium at 20% oxygen tension promoted the best hyaline-like neocartilage tissue production. Glucosamine sulfate supplementation, low oxygen tension, 5 mM glucose concentration and a transient TGF-β3 supplementation were not beneficial for the neocartilage formation in the scaffold-free cell culture system. In the third study, we used these newly defined, optimized culture conditions to produce the neocartilage tissues in the HyStem™ and the HydroMatrix™ scaffold materials and we compared these tissues to the ones grown as scaffold-free control cultures. We noticed that there was no difference between the controls and the scaffolds, and occasionally the scaffold-free controls had produced better quality cartilage than the ones with the scaffolds. Overall, the neocartilage tissues were of good hyaline-like quality in the third study. Their extracellular matrix contents were close to the native cartilage, although the neotissues lacked the zonal organization typical to the normal articular cartilage. The tissues had the right components, but their ultrastructure differed from the native cartilage. In conclusion, we were able to optimize our in vitro neocartilage culture method further, and discovered a good combination of the culture conditions to produce hyaline-like cartilage of good quality. Surprisingly, the scaffold materials were not beneficial for the cartilage formation. / Lasi- eli hyaliinirusto on pitkälle erikoistunutta kudosta, jolla on erittäin tärkeä rooli yksilön nivelten toiminnassa. Kudos suojaa ruston alapuolista luuta muodostamalla lähes kitkattoman ja joustavan liikkumista helpottavan pinnan. Lasiruston oma uusiutumiskyky on hyvin heikko, ja näin ollen kudos vain harvoin paranee alkuperäisen kaltaiseksi vaurion jälkeen. Ylipaino, vammat, liiallinen kuormitus tai geneettiset tekijät voivat käynnistää rustokudoksen rappeutumisen. Tätä tilaa kutsutaan nivelrikoksi. Nivelrikko on valtava kansanterveydellinen ongelma. Keinonivelleikkaus on nykyisellään ainoa hoitokeino pinta-alaltaan laajojen nivelruston vaurioiden hoitoon. Vaihtoehtoja tämän suuren ja invasiivisen kirurgisen operaation korvaamiseksi tutkitaan kuitenkin koko ajan ympäri maailmaa. Kudosteknologian ajatuksena on optimoida solujen, biomateriaalien ja erilaisten kasvatusolosuhteiden käyttö uuden, alkuperäisen kaltaisen toiminnallisen kudoksen luomiseksi vauriokohtaan. Väitöskirjan kaikissa kolmessa osatutkimuksessa uudisrustokudoksia tuotettiin käyttäen naudan polven rustosta eristettyjä primäärisiä rustosoluja. Näytteet kerättiin histologisia analyysejä, geenin ilmentymistutkimuksia ja proteoglykaanisisällön ja -jakauman (PG) analyyseja varten. Histologisista leikkeistä värjättiin tyypin II kollageeni ja PG:t, ja kvantitatiivista RT-PCR -menetelmää käytettiin aggrekaani-, Sox9-, prokollageeni α2(I)- ja prokollageeni α1(II)-geenien suhteellisten ilmentymistasojen määrittämiseen. Proteoglykaanisisältö analysoitiin käyttäen spektrofotometristä menetelmää, ja PG:t eroteltiin kokonsa perusteella agaroosigeelielektroforeesia käyttäen. Kahdessa ensimmäisessä osatutkimuksessa optimoitiin tukirakenteetta kasvattujen uudisrustojen kasvatusolosuhteita natiivin kaltaisen lasiruston tuottamiseksi. Havaitsimme, että korkea glukoosipitoisuus ja hypertoninen elatusaine yhdistettynä 20 % happiosapaineeseen tuotti parhaimman laatuista uudisrustokudosta tutkituista yhdistelmistä. Glukosamiinisulfaatin lisäys, matala happiosapaine, 5 mM glukoosi konsentraatio tai TGF-β3:n lisääminen alkuvaiheessa eivät edesauttaneet uudisrustokudosten muodostumisessa. Kolmannessa osatutkimuksessa otettiin käyttöön uudet, hyväksi havaitut kasvatusolosuhteet yhdistettynä HyStem™ and HydroMatrix™ -tukimateriaaleihin, ja niitä verrattiin tukirakenteettomaan kasvatusmenetelmään. Tutkimuksessa havaittiin, ettei tukirakenteettoman kontrollin tai tukimateriaalien välillä ollut mitään eroa, ja että kontrollikasvatukset tuottivat ajoittain jopa parempaa rustoa kuin tukimateriaalein kasvatetut. Kaiken kaikkiaan kaikki tuotetut uudiskudokset muistuttivat laadullisesti lasiruston kaltaista kudosta. Molekyylisisältö lähenteli natiivia rustoa, vaikkakin uudiskudoksista puuttui normaalille nivelrustolle tyypillinen vyöhykkeinen järjestäytyminen. Kudoksissa oli parhaimmillaan oikea määrä oikeita komponentteja, mutta ne eivät vain olleet järjestäytyneet oikealla tavalla. Onnistuimme optimoimaan uudisrustokudosten kasvatusmenetelmäämme. Löysimme hyvän kasvatusolosuhteiden yhdistelmän, jonka avulla kykenimme tuottamaan lasiruston kaltaista uudisrustokudosta. Hivenen yllättäenkin, tukimateriaalit eivät olleet avuksi tutkimuksessamme uudisrustokudoksia muodostettaessa.

Submitted by CAMILA LEONEL DA SILVA null (camilaleonels_1@hotmail.com) on 2016-05-02T19:33:26Z No. of bitstreams: 1 TESE - Camila Leonel da Silva.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-04T19:19:33Z (GMT) No. of bitstreams: 1 silva_cl_dr_sjrp.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) / Made available in DSpace on 2016-05-04T19:19:33Z (GMT). No. of bitstreams: 1 silva_cl_dr_sjrp.pdf: 12839463 bytes, checksum: a432431aa8b8009a0183a4c0896c3e34 (MD5) Previous issue date: 2016-04-23 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A transição epitélio-mesenquimal (EMT) é o processo pelo qual as células cancerosas a partir de tumores primários passam por uma conversão fenotípica para invadir e migrar, gerar metástases em tecidos ou órgãos distantes. Este processo pode ser induzido por fatores de crescimento, tais como Fator de Crescimento Transformante beta (TGF-β) e sua alta expressão tem sido implicada na angiogênese tumoral, na migração e invasão celular em muitos tipos de tumores. A expressão de ROCK-1 está associada com a malignidade dos tumores, enquanto a inibição desta molécula resulta em uma supressão significativa de metástases tumorais. A metformina, um fármaco utilizado no tratamento da diabetes, demonstrou inicialmente inibir a EMT e impedir o fenótipo mesenquimal pela repressão transcricional de pontos chave da regulação da EMT (ZEB1, TWIST1, SNAIL2, TGF-β) em células de câncer de mama. Os objetivos foram avaliar a expressão gênica e proteica de marcadores relacionados a metástase, em um estudo in vitro e in vivo, em linhagens de câncer de mama, após o tratamento com metformina, além do silenciamento gênico do TGF-β1 para inibição da transição epitélio-mesenquimal. Foi realizado a transfecção da linhagem celular metastática de tumor mamário canino CF41 de forma estável após a construção de um pequeno RNA de interferência para desenvolver derivados clonais que expressam níveis reduzidos de TGF-β1 (células TGF-β1sh). Este foi subsequentemente combinado com o tratamento com metformina, para analisar os efeitos sobre a migração de células, assim como a expressão dos marcadores de EMT E-caderina e N-caderina, quantificados através de imunofluorescência e do qRT-PCR. As linhagens mamárias humanas MCF-7 (não-metastática) e MDA-MB-231 (metastática) foram tratadas com metformina e inibidor Y27632, após a indução da EMT por TGF-β1 para examinar os efeitos sobre a migração destas células, bem como a expressão proteica dos marcadores ROCK-1, vimentina, E-caderina, CD44 e CD24 por imunocitoquímica. Em um estudo in vivo, as células não modificadas CF41 ou que expressam TGF-β1 shRNA foram injetadas na região inguinal de camundongos fêmea nude atímicos tratados com metformina. Os camundongos foram eutanasiados após o tratamento e os pulmões foram recolhidos para avaliação do número de metástases. As regiões metastáticas foram subsequentemente avaliadas pela expressão de N-caderina, E-caderina, vimentina e claudina-7 através da imuno-histoquímica. Foi possível avaliar que a taxa de migração e invasão foi menor em células TGF-β1sh, em comparação com as células parentais CF41 e esta inibição foi significativa quando combinado com o tratamento com metformina. As análises in vitro demonstraram que o tratamento com metformina reduziu a expressão de N-caderina e aumentou a expressão de E-caderina nas células CF41 e TGF-β1sh. Os resultados demonstram também que após a indução do TGF-β1 nas linhagens MCF-7 e MDA-MB-231 houve menor expressão das proteínas ROCK-1, vimentina, CD44 e CD24 em ambas as linhagens após tratamento com metformina e Y27632. Nas células MDA-MB-231 a expressão de E-caderina foi maior em todos os grupos de tratamento. O tratamento da linhagems MDA-MB-231 com metformina e Y27632 reduziu significativamente a invasão destas células. O estudo in vivo demonstrou que o tratamento com metformina reduziu o número de metástases pulmonares em animais portadores de tumores induzidos com as células TGF-β1sh. Houve diminuição da expressão de marcadores mesenquimais N-caderina e vimentina, e aumento da expressão de marcadores epiteliais E-caderina e claudina-7 nas metástases pulmonares. Assim, concluimos que este estudo confirma os benefícios do silenciamento do TGF-β1, além do tratamento com metformina e Y27632 como potenciais agentes terapêuticos em tumores de mama, bloqueando o processo de EMT e seu potencial metastático. / Epithelial mesenchymal transition (EMT) is the process by which cancer cells from primary tumors pass through a phenotypic conversion to invade and migrate, generating metastases in organs or tissues distant. This process can be induced by growth factors such as transforming growth factor beta (TGF-β) and its overexpression has been implicated in tumor angiogenesis, cell migration and invasion in many cancers. ROCK-1 expression is associated with the malignant character of tumors, while inhibiting this molecule results in a significant suppression of tumor metastasis. Metformin, a drug use for the treatment of diabetes, was previously shown to inhibit EMT by suppressing expression of key transcription factors in breast cancer cells. The aims were to evaluate the gene expression and protein expression of related markers metastasis, in a study in vitro and in vivo in breast cancer cell lines after treatment with metformin in addition to the gene silencing of TGF-β1 for inhibiting epithelial-mesenquimal transition. These aims were contemplated performing transfected of canine metastatic mammary tumor cell line CF41 with small interfering RNA constructs to develop clonal derivatives expressing reduced levels of TGF-β1 (TGF-β1sh cells). This was subsequently combined with metformin treatment, to look at effects on cell migration, as well as the expression of the EMT markers E-cadherin and N-cadherin, which were quantified by immunofluorescence and qRT-PCR. MCF-7 and MDA-MB-231 cell lines were treated with metformin and Y27632, after induction of EMT by TGF-β1, to examine the effects on cell migration as well as the protein expression of the ROCK-1 markers, vimentin, E-cadherin, CD44 and CD24 by immunocitochemistry. In an in vivo study, unmodified or TGF-β1 shRNA-expressing CF41 cells were injected in the inguinal region of nude athymic female mice that were treated with metformin. Mice were sacrificed after treatment and the lungs were collected to assess the number of metastases. Metastatic nodules were subsequently assessed for, N-cadherin, E-cadherin, vimentin and claudin-7 expression via immunohistochemistry. With the obtained results it was possible to assess the migration and invasion rate was lower in TGF-β1sh cells as compared to parental CF41 cells and this inhibition was significant when combined with metformin treatment. In vitro analyses demonstrated that metformin treatment reduced n-cadherin expression and increased E-cadherin expression in both CF41 and TGF-β1sh cells. After TGF-β1 induction in MDA-MB231 and MCF-7 cell lines, there was a lower protein expression of ROCK-1, vimentin, CD44 and CD24 in both cell lines after treatment with metformin and Y27632. In MDA-MB-231 cells, E-cadherin expression was increased in all treatment groups. Treatment of MDA-MB-231 cell line with metformin and Y27632 significantly reduced the invasion of these cells. In vivo studies demonstrated that metformin treatment reduced the number of lung metastases in animals bearing TGF-β1sh tumors. This paralleled a decreased expression of mesenchymal markers N-cadherin and vimentin, and increased expression of epithelial markers E-cadherin and claudin-7 in lung metastases.This study confirms the benefits of TGF-β1 silencing in addition to metformin and Y27632 as potential therapeutic agents in mammary tumors, by blocking EMT process and metastatic potential. / FAPESP: 2012/09778-1

Platelet-rich plasma (PRP) is an autogenous product obtained from whole blood, through one or two centrifugations process. The resulting small volume of plasma contains a high platelets numbers and their growth factors. The aim of this study was to evaluate different protocols to obtain PRP using the manual method according to their capacity to concentrate platelets, leukocytes and erythrocytes contamination and the correlation between platelet count and growth factor TGF-β1 levels in the PRP samples. Ten healthy horses with mean age of 7 years (± 2.39), weighing on average 500 kg (± 67.1) were used to evaluate seven protocols to obtain PRP. The protocols tested varied according to speed and time used on both centrifugations. The variables analyzed on the PRP samples were: platelet concentration, leukocytes and erythrocytes, TGF-β1 levels quantified by ELISA. No significant differences between protocols were observed regarding the ability to concentrate platelet and the levels of TGF-β1. However, protocol PI showed significantly more erythrocyte and leukocyte contamination in PRP samples than the other protocols, being considered an inadequate protocol for the volume of blood used in this experiment. The remaining protocols are suitable for extracting PRP. Although the PRP is an option of therapy in equine medicine, many gaps regarding their compliance must still be met. / O plasma rico em plaquetas (PRP) é obtido a partir do sangue total, através de uma ou duas centrifugações, resultando em um pequeno volume de plasma com elevado número de plaquetas contendo fatores de crescimento. O objetivo do presente estudo foi avaliar diferentes protocolos para obtenção de PRP através do método manual quanto à capacidade de concentração das plaquetas, contaminação com leucócitos e hemácias, e correlacionar a concentração plaquetária com os níveis do fator de crescimento TGF-β1 nas amostras de PRP. Dez equinos, sadios, com idade média de 7 anos (±2,39), pesando em média 500kg (± 67,1) foram usados para avaliar sete protocolos de obtenção de PRP. Os protocolos testados variaram quanto à velocidade e tempo nas duas centrifugações. As variáveis analisadas nas amostras de PRP foram: concentração de plaquetas, presença de leucócitos e hemácias, e níveis de TGF-β1 quantificados pelo teste ELISA. Os resultados deste estudo não demonstraram diferenças significativas entre os protocolos testados quanto à capacidade de concentração plaquetária e quanto aos níveis de TGF- β1. Entretanto, foram observadas diferenças significavas entre o protocolo I aos demais protocolos devido a este apresentar maior número de hemácias e leucócitos nas amostras de PRP, sendo por isto considerado inadequado para o volume de sangue utilizado. Os demais protocolos podem ser utilizados para obtenção de PRP de sangue eqüino. Apesar do PRP ser uma opção de terapia na medicina equina, muitas lacunas relativas ao seu respeito ainda devem ser preenchidas.

A leishmaniose visceral causada por Leishmania infantum chagasi à caracterizada pela perda da habilidade do hospedeiro gerar uma resposta imunolÃgica eficaz. Neste estudo, foi investigado o papel da quimiocina CXCL10 no controle da infecÃÃo por L. infantum chagasi in vivo. Grupos de camundongos BALB/c foram tratados ou nÃo com CXCL10 (5 μg/kg) com 1, 3 e 7 dias de infecÃÃo e apÃs 1, 7 e 23 dias do tratamento, alguns parÃmetros foram avaliados: a carga parasitÃria, os nÃveis de IFN-, IL-4, TGF-β e IL-10, e as alteraÃÃes histopatolÃgicas no fÃgado. ApÃs 23 dias de tratamento, CXCL10 induziu, no baÃo, uma reduÃÃo expressiva no nÃmero de parasitos, quando comparado ao grupo controle. No fÃgado, a carga parasitÃria mostrou uma queda no grupo tratado, entre o 7 e 23 dia apÃs o tratamento. Entretanto, o efeito leishmanicida de CXCL10, neste trabalho, nÃo parece ser mediado por NO, uma vez que nÃo houve diferenÃa na produÃÃo de NO entre os grupos. IFN-γ foi induzida de maneira mais significativa no grupo tratado do que nos controles, e atingiu sua produÃÃo mÃxima (100 pg/mL) no 23 dia apÃs o tratamento, correlacionando-se com a queda da carga parasitÃria nos ÃrgÃos-alvo. IL-4 foi produzida em baixas concentraÃÃes, em ambos os grupos, embora os animais tratados com CXCL10 tenham mostrado nÃveis mais elevados do que os controles. Em relaÃÃo Ãs citocinas antiinflamatÃrias, apÃs 23 dias do tratamento, os nÃveis de IL-10 nos animais tratados foram menores do que os do controle. A produÃÃo de TGF-β apÃs 7 dias do tratamento foi 2 vezes menor no grupo tratado quando comparado ao controle, e apÃs 23 dias do tratamento, essa citocina continuou com nÃveis mais baixos do que aqueles observados no controle. Na anÃlise histopatolÃgica do fÃgado apÃs o 1 dia do tratamento, foram encontrados, em ambos os grupos, mais granulomas imaturos (GI), do que infiltrados nÃo granulomatosos (NG) e alguns poucos granulomas maduros (GM) apenas no grupo tratado. ApÃs 7 dias do tratamento, a quantidade de infiltrados NG estava menor e os GI ainda foram os mais encontrados, em ambos os grupos, alÃm disso, foi observado um pequeno aumento de GM no grupo tratado. Em resumo, diante dos resultados encontrados, à possÃvel sugerir um importante papel leishmanicida de CXCL10 em camundongos BALB/c infectados por L. infantum chagasi, que parece ser mediado por uma expressiva produÃÃo de IFN-g e supressÃo das citocinas imunorreguladoras, IL-10 e TGF-β, abrindo a hipÃtese se isto nÃo estaria associado a uma diminuiÃÃo na frequÃncia de cÃlulas T regulatÃrias, induzida por CXCL10, nesses animais. / Visceral leishmaniasis caused by Leishmania infantum chagasi is characterized by the loss of the ability of host to generate an effective immune response. In this study it was investigated the role of CXCL10 chemokine in controlling L. infantum chagasi infection in vivo. Groups of BALB/c mice were treated or not with recombinant CXCL10 chemokine (5 μg/kg) with 1, 3 and 7 days of infection and after 1, 7 and 23 days of treatment, some parameters were evaluated: parasite load, levels of IFN-g, IL-4, TGF-β and IL-10, and the histopathological alterations in the liver. After 23 days of treatment, CXCL10 induced in the spleen a significant reduction on the number of parasites as compared to control group. In the liver, parasite load decreased in treated group between the 7th and 23th day post treatment. However, the antileishmanial effect of CXCL10, in this work, does not seem to be mediated by NO, since there was no difference in the NO production among the groups. IFN-γ was induced most significantly in treated group than in controls, and reached its maximum production (100 pg/mL) on day 23 after treatment, correlating with the reduction in parasite burden in target organs. IL-4 was produced in low doses, in both groups, although treated animals had shown higher levels than control group. Regarding to anti-inflammatory cytokines, after the 23th day of treatment, IL-10 levels in treated animals were smaller than in control group. Production of TGF-β after 7 days of treatment was 2 times lower in treated group when compared to control, and after the 23th day of treatment, this cytokine remained with lower levels than those observed in control. In the histopathological analysis of the liver after the 1st day of treatment, were found in both groups more immature granulomas (GI) than non-granulomatous infiltrate (NG), and some few mature granulomas (GM) were only observed in treated group. After 7 days of treatment, the amount of NG infiltrates was lower, and GI were still the most frequent in both groups, besides a slight increase of GM was observed in treated group. In summary, at the light of the found results, it is possible to suggest an important leishmanicidal role to CXCL10 in BALB/c mice infected by L. infantum chagasi, which seems to be mediated by a significant IFN-g production, and suppression of immunoregulatory cytokines, IL-10 and TGF-β, opening the hypothesis that this would be associated to a decrease in the frequency of regulatory T cells induced by CXCL10 in these animals.

Background: Different types of cardiomyopathies are associated with variable hypertrophic response. <p>A number of growth factors are thought to play a role in pathologic cardiac remodeling. <p>Aims: We compared the modulation of the TGF-ƒÒ superfamily and IGF-1 signaling pathways and their target genes, the cell cycle regulatory proteins in tachycardia-induced dilated cardiomyopathy, a model with no detectable hypertrophy and in ischemic cardiomyopathy, a model with a marked hypertrophic reaction. <p>Methods: In the first study, endomyocardial biopsies were obtained weekly in 15 dogs, during the development of tachycardiomyopaty. Genes involved in the myostatin-TGF-ƒÒ-Activin-A/Smad signaling pathway, p21 and cyclin D were quantified and correlated to echocardiographic measures of hypertrophy. In the second study, myocardial tissue samples were obtained in 8 dogs with a healed myocardial infarction, in 8 dogs with heart failure induced by overpacing and in 7 healthy dogs. We measured gene expression of IGF-1, its receptor (IGF-1R) and cyclins A, B, D1, D2, D3 and E and correlated them to the level of hypertrophy. <p>Results: Tachycardiomyopathy was characterized by chambers dilation with no identifiable hypertrophy. Ischemic cardiomyopathy was characterized by eccentric hypertrophy. In tachycardiomyopathy, Activin-A mRNA was 4-fold higher than at baseline. Smad7 was overexpressed in severe heart failure; p21, a direct target gene of the Smad pathway was upregulated 8-fold and cyclin D1 was down-regulated. In that model, IGF-1 was overexpressed but neither IGF-1R nor any of the cyclins studied.<p> In ischemic cardiomyopathy, IGF-1, IGF-R, and cyclins B, D1, D3 and E gene expression were upregulated.<p> In tachycardiomyopathy, Activin-A and p21 were inversely correlated to the thickness of the interventricular septum. In normal dogs and in the both models of cardiomyopathy, IGF-1R was correlated to the thickness of the interventricular septum and to cyclins. <p>Conclusions: Taken together, these results agree with the notion that Activin-A, IGF and cyclins are involved in the modulation of hypertrophic response observed in cardiomyopathies. <p> / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished

Transforming growth factor β (TGF-β) and bone morphogenetic protein (BMP) signaling pathways are involved in many physiological processes during embryonic and adult life. TGF-β promotes epithelial to mesenchymal transition (EMT). We identified a gene target of TGF-β signaling, encoding the salt-inducible kinase 1 (SIK1). A potential substrate of this kinase, the polarity protein Par3, is an established regulator of tight junction assembly. SIK1 associates with Par3, can potentially phosphorylate Par3 and leads to its degradation, contributing to tight junction disassembly. Glioblastoma multiforme (GBM) is a common malignancy in the central nervous system, characterized by high heterogeneity, invasiveness, and resistance to therapy. One of the causes of heterogeneity and therapy-resistance is the existence of glioblastoma stem cells (GSCs). TGF-β signaling promotes self-renewal while BMP signaling induces differentiation of GSCs. Snail is a potent inducer of the EMT in carcinomas. However, in the context of GBM, Snail induces BMP signaling and represses TGF-β signaling through interaction with SMADs, the signaling mediators of TGF-β and BMP. In conclusion, Snail differentially regulates the activity of the opposing BMP and TGF-β pathways, thus promoting an astrocytic fate switch and repressing stemness in GSCs. Although profound changes in cell polarity is a hallmark of invasive malignancies, little is known about the role of the polarity machinery in tumor suppression. Patient transcriptomic data suggested low Par3 expression, correlating with poor survival of the GBM patients. Par3 silencing decreased the GSC self-renewal capacity and enhanced their invasiveness. Transcriptomic analysis indicates that loss of Par3 leads to downregulation of genes encoding mitochondrial enzymes that generate ATP. These results support a novel role of Par3 in GBM, beyond its contribution to junctional contacts between cells. Another regulator of TGF-β and BMP signaling is the liver kinase B1 (LKB1). According to GBM patient mRNA analysis, high levels of LKB1 correlate with poor prognosis. Silencing of LKB1 in GSCs impairs invasion and self-renewal capacity due to downregulation of genes involved in these processes. Moreover, loss of LKB1 induces mitochondrial dysfunction, leading to decreased ATP levels. Collectively, this thesis has delivered a group of novel regulatory pathways that control critical aspects of cancer cell polarity, invasion and stemness.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Morphogens are secreted signalling molecules that are expressed in restricted groups of cells within the developing tissue. From there, they are secreted and travel throughout the target field and form concentration gradients. These concentration profiles endow receiving cells with positional information. A number of experiments in Drosophila demonstrated that the morphogen Decapentaplegic (Dpp) forms activity gradients by inducing the expression of several target genes above distinct concentration thresholds at different distances from the source. This way, Dpp contributes to developmental fates in the target field such as the Drosophila wing disc. Although the tissue distribution as well as the actual shape and size of the Dpp morphogen concentration gradient has been visualized, the cell biological mechanisms through which the morphogen forms and maintains a gradient are still a subject of debate. Two hypotheses as to the dominant mechanism of movement have been proposed that can account for Dpp spreading throughout the Drosophila wing imaginal target tissue: extracellular diffusion and planar transcytosis, i. e. endocytosis and resecretion of the ligand that is thereby transported through the cells. Here, I present data indicating that implications of a theoreticalanalysis of Dpp spreading, where Dpp transport through the target tissue is solely based on extracellular diffusion taking into account receptor binding and subsequent internalization, are inconsistent with experimental results. By performing Fluorescence Recovery After Photobleaching (FRAP) experiments, I demonstrate a key role of Dynamin-mediated endocytosis for Dpp gradient formation. In addition, I show that most of GFP-Dpp traffics through endocytic compartments at the receiving epithelial cells, probably recycled through apical recycling endosomes (ARE). Finally, a Dpp recycling assay based on subcellular photouncage of ligand is presented to address specifically the Dpp recycling event at the receiving cells.

During cell communication, cells produce secreted signals termed morphogens, which traffic through the tissue until they are received by target, responding cells. Using the fruit fly Drosophila melanogaster as a model organism, I have studied transforming growth factor-beta (TGF-beta) signal from the secreting to the receiving cells in the developing wing epithelial cells and at the neuromuscular junctions. Cell culture studies have suggested that cells modulate morphogenetic signaling by expressing the receptors and secreting the ligand in spatially defined areas of the cell. Indeed, I have found that TGF-beta ligands, receptors and R-Smads show a polarized distribution both in the epithelial cells and at the synapses. My results indicate that the cellular junctions define a signaling domain within the plasma membrane, to which TGF-beta signaling machinery is targeted. In the context of epithelial cells, the junctions play a role in TGF-beta signaling regulation through their component beta-cat. A complex forms between beta-cat and the R-Smad Mad, but the mechanism by which beta-cat modulates signaling is not yet understood. At the synapse, the sub-cellular localization of TGF-beta pathway components indicates the occurrence of an anterograde signal. Moreover, my results suggest a scenario in which TGF-beta signaling is coupled with synaptic activity: quanta of growth factor, released upon neurostimulation together with neurotransmitter quanta, could modulate therefore the development and the function of the synapse.