Thèse (M.Sc.)--Université Laval, 2004. / Bibliogr.: f. 75-79. Publié aussi en version électronique.

INTRODUÇÃO: O desenvolvimento das glândulas salivares envolve um processo coordenado de interações moleculares complexas, nas quais as integrinas têm papel fundamental. As integrinas são uma família de receptores transmembrânicos, heterodímeros, compostos por duas subunidades: alfa e beta que estão ligadas de forma não covalente e dependentes de cations bivalentes. Estes heterodímeros medeiam sinais intra e extracelulares envolvidos na organização das células em tecidos e órgãos durante seu desenvolvimento. Em particular a integrina beta1 está envolvida na proliferação e diferenciação de células no desenvolvimento dos tecidos epiteliais. OBJETIVOS: Para compreender o papel da integrina beta1 no desenvolvimento das glândulas salivares humanas, estudamos a sua expressão por meio da hibridização in situ em tecido fetal humano em desenvolvimento. MATERIAL E MÉTODOS: A hibridização in situ com o método chromogenic in situ hibridization (CISH) foi utilizada para investigar a expressão genética da integrina beta1 em espécimes de glândulas salivares em desenvolvimento derivados de 30 fetos humanos em vários estágios gestacionais (de 825 semanas de vida intrauterina). Os resultados obtidos com a hibridização in situ foram relacionados com os aspectos morfológicos das glândulas salivares em desenvolvimento em cada fase da evolução da morfogênese glandular, por meio de análise qualitativa. RESULTADOS: Expressão da integrina beta1 foi detectada em raras células na fase prebotão. A expressão dessa molécula foi detectada em mais estruturas com a evolução do desenvolvimento morfogenético das glândulas salivares. CONCLUSÕES: A expressão a integrina beta1 parece ser regulada de forma temporoespacial e é associada ao estabelecimento do fenótipo maduro das glândulas salivares / INTRODUCTION: Salivary gland development entails coordinated processes involving complex molecular interactions in which integrins have a fundamental role. The integrins are a family of heterodimeric transmembrane receptors comprising alpha and beta subunits that mediate intercellular and extracellular signals involved in the organisation of cells in tissues and organs during development. The beta1 integrin in particular have been implicated in proliferation and differentiation of cells involved in the development of epithelial tissues. OBJECTIVE: To understand the role of beta1 integrin in salivary gland development we have studied its expression in human foetal tissues. MATERIAL AND METHODS: In situ hybridisation CISH technique was used to compare the expression and localisation of integrin beta1 with differentiation markers in developing human salivary glands obtained from foetuses of 825 gestational weeks. RESULTS: Integrin beta1 first appeared during bud stage in a few cells and its distribution increased as salivary gland morphogenesis progressed. CONCLUSIONS: The developmentally regulated expression of integrin beta1 in association with the establishment of a mature phenotype of salivary glands is suggestive of its role in salivary gland morphogenesis

INTRODUÇÃO: O desenvolvimento das glândulas salivares envolve um processo coordenado de interações moleculares complexas, nas quais as integrinas têm papel fundamental. As integrinas são uma família de receptores transmembrânicos, heterodímeros, compostos por duas subunidades: alfa e beta que estão ligadas de forma não covalente e dependentes de cations bivalentes. Estes heterodímeros medeiam sinais intra e extracelulares envolvidos na organização das células em tecidos e órgãos durante seu desenvolvimento. Em particular a integrina beta1 está envolvida na proliferação e diferenciação de células no desenvolvimento dos tecidos epiteliais. OBJETIVOS: Para compreender o papel da integrina beta1 no desenvolvimento das glândulas salivares humanas, estudamos a sua expressão por meio da hibridização in situ em tecido fetal humano em desenvolvimento. MATERIAL E MÉTODOS: A hibridização in situ com o método chromogenic in situ hibridization (CISH) foi utilizada para investigar a expressão genética da integrina beta1 em espécimes de glândulas salivares em desenvolvimento derivados de 30 fetos humanos em vários estágios gestacionais (de 825 semanas de vida intrauterina). Os resultados obtidos com a hibridização in situ foram relacionados com os aspectos morfológicos das glândulas salivares em desenvolvimento em cada fase da evolução da morfogênese glandular, por meio de análise qualitativa. RESULTADOS: Expressão da integrina beta1 foi detectada em raras células na fase prebotão. A expressão dessa molécula foi detectada em mais estruturas com a evolução do desenvolvimento morfogenético das glândulas salivares. CONCLUSÕES: A expressão a integrina beta1 parece ser regulada de forma temporoespacial e é associada ao estabelecimento do fenótipo maduro das glândulas salivares / INTRODUCTION: Salivary gland development entails coordinated processes involving complex molecular interactions in which integrins have a fundamental role. The integrins are a family of heterodimeric transmembrane receptors comprising alpha and beta subunits that mediate intercellular and extracellular signals involved in the organisation of cells in tissues and organs during development. The beta1 integrin in particular have been implicated in proliferation and differentiation of cells involved in the development of epithelial tissues. OBJECTIVE: To understand the role of beta1 integrin in salivary gland development we have studied its expression in human foetal tissues. MATERIAL AND METHODS: In situ hybridisation CISH technique was used to compare the expression and localisation of integrin beta1 with differentiation markers in developing human salivary glands obtained from foetuses of 825 gestational weeks. RESULTS: Integrin beta1 first appeared during bud stage in a few cells and its distribution increased as salivary gland morphogenesis progressed. CONCLUSIONS: The developmentally regulated expression of integrin beta1 in association with the establishment of a mature phenotype of salivary glands is suggestive of its role in salivary gland morphogenesis

A hanseníase causada pelo Mycobacterium leprae é a infecção que mais gera danos ao sistema nervoso periférico. Este microrganismo tem como alvo a célula de Schwann, o qual se liga à laminina, um dos constituintes da lâmina basal. Através desta ligação o Mycobacterium leprae penetra nas células de Schwann onde se multiplica, infectando o sistema nervoso periférico e desse modo comprometendo sua estrutura e funções. Provavelmente tal como ocorre em outras neuropatias degenerativas, inflamatórias ou neoplásicas, no processo de agressão nervosa na hanseníase, participam outras moléculas como a integrina beta1 e a proteína S-100. O presente trabalho estudou 44 doentes de hanseníase, classificados de acordo com Ridley e Jopling, distribuídos em: 12 doentes indeterminados, 7 doentes tuberculóides, 17 doentes dimorfo-tuberculóides, 2 doentes dimorfo-dimorfos, 2 doentes dimorfo virchowianos e 4 doentes virchowianos. Os propósitos foram estudar o dano nervoso nas terminações nervosas da pele por meio da expressão da integrina beta1 e da proteína S100; e ainda a análise da relação entre as manifestações dermatológica, neurológica, reação de Mitsuda, bacterioscopia e os achados imunohistoquímicos. A alteração da expressão da integrina beta1 nas terminações nervosas da pele foi variável, precoce e constante em 100% dos doentes. A alteração da proteína S-100 nas terminações nervosas da pele nos doentes foi de 88,6%. Apesar da significativa correlação entre elas, a sensibilidade da integrina beta1 foi maior. Encontrou-se correlação entre a clínica dermatológica e neurológica, bem como com a bacteriscopia e a reação intradérmica de Mitsuda. Não houve correlação das reações imunohistoquímicas com os dados clínicos, provavelmente em decorrência das alterações moleculares ocorrerem antes das manifestações clínicas / Leprosy caused by Mycobacterium Leprae is the infection that most causes damage to the peripheral nervous system. This microorganism has its principal target in the Schwann cells, which bind themselves to laminin, one of the constituints of the basic lamina. The Mycobacterium Leprae, by way of this link, penetrates the Schwann cells, where they multiply, infecting the peripheral nervous system and thus compromising its structure and functions. Probably, as happens in other degenerative neuropathies, inflammatory or neoplastic, other molecules participate in the process of nervous aggression of leprosy, such as beta1 integrin and S-100 protein. This paper studied 44 patients with leprosy, classified according to Ridley and Jopling, distributed as: 12 indetermined patients, 7 tuberculoid patients, 17 borderline-tuberculoid patients, 2 mid-borderline patients, 2 borderline-lepromatous patients and 4 lepromatous patients. The aims were to study the damage to the skin nerve endings by way of the levels of beta1-integrin and S-100 protein; and also the analysis of relation between dermatological, neurological clinical manifestations, the Mitsuda reactions, bacterioscopical and the immunohistochemical findings. The alterations in the amounts of beta1 integrin in the skin nerve endings were variable, premature and constant in 100 % of the patients. The alteration in the S-100 level in the skin nerve endings in the patients was 88,6 %. In spite of the correlation between them, the sensibility of the beta1 integrin was greater. There was found to be correlation between dermatological and neurological clinical manifestations as well as with the bacterioscopy and the Mitsuda intradermal reactions. There was no correlation between immunohistochemical reactions with the clinical data, probably because of the molecular alterations that occur before the clinical manifestations

A hanseníase causada pelo Mycobacterium leprae é a infecção que mais gera danos ao sistema nervoso periférico. Este microrganismo tem como alvo a célula de Schwann, o qual se liga à laminina, um dos constituintes da lâmina basal. Através desta ligação o Mycobacterium leprae penetra nas células de Schwann onde se multiplica, infectando o sistema nervoso periférico e desse modo comprometendo sua estrutura e funções. Provavelmente tal como ocorre em outras neuropatias degenerativas, inflamatórias ou neoplásicas, no processo de agressão nervosa na hanseníase, participam outras moléculas como a integrina beta1 e a proteína S-100. O presente trabalho estudou 44 doentes de hanseníase, classificados de acordo com Ridley e Jopling, distribuídos em: 12 doentes indeterminados, 7 doentes tuberculóides, 17 doentes dimorfo-tuberculóides, 2 doentes dimorfo-dimorfos, 2 doentes dimorfo virchowianos e 4 doentes virchowianos. Os propósitos foram estudar o dano nervoso nas terminações nervosas da pele por meio da expressão da integrina beta1 e da proteína S100; e ainda a análise da relação entre as manifestações dermatológica, neurológica, reação de Mitsuda, bacterioscopia e os achados imunohistoquímicos. A alteração da expressão da integrina beta1 nas terminações nervosas da pele foi variável, precoce e constante em 100% dos doentes. A alteração da proteína S-100 nas terminações nervosas da pele nos doentes foi de 88,6%. Apesar da significativa correlação entre elas, a sensibilidade da integrina beta1 foi maior. Encontrou-se correlação entre a clínica dermatológica e neurológica, bem como com a bacteriscopia e a reação intradérmica de Mitsuda. Não houve correlação das reações imunohistoquímicas com os dados clínicos, provavelmente em decorrência das alterações moleculares ocorrerem antes das manifestações clínicas / Leprosy caused by Mycobacterium Leprae is the infection that most causes damage to the peripheral nervous system. This microorganism has its principal target in the Schwann cells, which bind themselves to laminin, one of the constituints of the basic lamina. The Mycobacterium Leprae, by way of this link, penetrates the Schwann cells, where they multiply, infecting the peripheral nervous system and thus compromising its structure and functions. Probably, as happens in other degenerative neuropathies, inflammatory or neoplastic, other molecules participate in the process of nervous aggression of leprosy, such as beta1 integrin and S-100 protein. This paper studied 44 patients with leprosy, classified according to Ridley and Jopling, distributed as: 12 indetermined patients, 7 tuberculoid patients, 17 borderline-tuberculoid patients, 2 mid-borderline patients, 2 borderline-lepromatous patients and 4 lepromatous patients. The aims were to study the damage to the skin nerve endings by way of the levels of beta1-integrin and S-100 protein; and also the analysis of relation between dermatological, neurological clinical manifestations, the Mitsuda reactions, bacterioscopical and the immunohistochemical findings. The alterations in the amounts of beta1 integrin in the skin nerve endings were variable, premature and constant in 100 % of the patients. The alteration in the S-100 level in the skin nerve endings in the patients was 88,6 %. In spite of the correlation between them, the sensibility of the beta1 integrin was greater. There was found to be correlation between dermatological and neurological clinical manifestations as well as with the bacterioscopy and the Mitsuda intradermal reactions. There was no correlation between immunohistochemical reactions with the clinical data, probably because of the molecular alterations that occur before the clinical manifestations

Centrosomes are major microtubule organizing centres that set up an internal microtubule (MT) network contributing to cell shape and to the formation of the mitotic spindle during cell division. Rearrangement of this MT array can be dictated by the centrosome and occurs during cell adhesion, polarization and migration. However, little is known about what regulates centrosome assembly and maintenance. beta1-integrins are common cell surface receptors and we show that beta1-integrin signalling is necessary for modulation of centrosome dynamics. In an attempt to identify the downstream components of beta1-integrin signalling involved, we also discovered that the activation of focal adhesion kinase or integrin linked kinase are not required in maintaining centrosome integrity. This would indicate that a non-canonical signalling beta1-integrin pathway might be involved in controlling centrosomal dynamics. This gives us greater insight into the mechanisms that control centrosomal stability and may lead to the better understanding of diseases like cancer and diseases, i.e. lissencephaly, which involve defects in cell polarization and asymmetric cell division, where the centrosome seems to have an important role.

No description available.

Dans les tissus périphériques, les lymphocytes T interagissent, grâce aux intégrines de la famille βi, avec les constituants de la matrice extracellulaire dont la plus abondante est le collagène. Cependant, la régulation des fonctions effectrices des lymphocytes T par ces intégrines reste peu connue. Les intégrines liant le collagène peuvent être des régulateurs importants pour la survie et pour les fonctions ostéoclastogéniques des lymphocytes T menant à la dégradation osseuse associée à l'arthrite rhumatoïde. Nos travaux ont démontré que l'interaction des lymphocytes T leucémiques avec le collagène de type I (Coll I) via l'intégrine a2β1 inhibe l'apoptose de ces cellules induite par la doxorubicine : une drogue utilisée en chimiothérapie. Nous avons montré que le Coli I protège les lymphocytes T leucémiques des effets cytotoxiques dé la doxorubicine en inhibant l'expression de RANKL. Ces résultats suggèrent fortement que l'intégrine a2β1 peut contribuer à la résistance des lymphocytes T leucémiques face aux traitements chimiothérapeutiques. Nous avons également montré que cette intégrine inhibe l'expression de RANKL et augmente celle de l'IFNγ par les lymphocytes T effecteurs activés par le TCR. Puisque RANKL est une cytokine importante pour le développement des ostéoclastes qui sont impliquées dans la dégradation osseuse inflammatoire et que l'IFNγ inhibe l'effet de RANKL, nos résultats suggèrent que l'intégrine a2β1 pourrait protéger les tissus osseux de la dégradation osseuse et pourrait représenter un mécanisme homéostatique. Par contre, nous avons montré que l'activation de l'intégrine alpl par le Coli IV augmente la production de RANKL sans affecter celle de l'lFNγ par les lymphocytes T effecteurs. De plus, le Coli IV synergise avec l'IL-7 pour augmenter la production de RANKL par ces cellules. Ainsi, les lymphocytes T activés par le Coli IV et l'IL-7 ont la capacité d'induire le développement des ostéoclastes à partir de monocytes et leurs effets sont également additifs. Le Coli IV augmente également la capacité de l'IL-7 à protéger les lymphocytes T contre l'apoptose induite par la privation en IL-2. Ces résultats montrent que l'intégrine aipi peut contribuer à la pathogénécité des lymphocytes T arthritiques en augmentant

No description available.

Articular cartilage is an avascular and flexible connective tissue found in joints. It produces a cushioning effect at the joints and provides low friction to protect the ends of the bones from wear and tear/damage. It has poor repair capacity and any injury can result pain and loss of mobility. One of the common forms of articular cartilage disease which has a huge impact on patient's life is arthritis. Research on cartilage cell/tissue engineering will help patients to improve their physical activity by replacing or treating the diseased/damaged cartilage tissue. Cartilage cell, called chondrocyte is embedded in the matrix (Lacunae) and has round shape in vivo. The in vitro monolayer culture of primary chondrocyte causes morphological change characterized as dedifferentiation. Transforming growth factor-beta (TGF-β), a cytokine superfamily, regulates cell function, including differentiation and proliferation. The effect of TGF-β1, 2, 3, and their manipulated forms in biological regulation of primary chondrocyte was investigated in this work. A novel method was developed to isolate and purify the primary chondrocytes from knee joint of neonate Sprague-Dawley rat, and the effect of some supplementations such as hyaluronic acid and antibiotics were also investigated to provide the most appropriate condition for in vitro culture of chondrocyte cells. Addition of 0.1mg/ml hyaluronic acid in chondrocyte culture media resulted an increase in primary chondrocyte proliferation and helped the cells to maintain chondrocytic morphology. TGF-β1, 2 and 3 caused chondrocytes to obtain fibroblastic phenotype, alongside an increase in apoptosis. The healing process of the wound closure assay of chondrocyte monolayers were slowed down by all three isoforms of TGF-β. All three types of TGF-β negatively affected the strength of chondrocyte adhesion. TGF-β1, 2 and 3 up regulated the expression of collagen type-II, but decreased synthesis of collagen type-I, Chondroitin sulfate glycoprotein, and laminin. They did not show any significant change in production of S-100 protein and fibronectin. TGF-β2, and 3 did not change expression of integrin-β1 (CD29), but TGF-β1 decreased the secretion of this adhesion protein. Manipulated TGF-β showed huge impact on formation of fibroblast like morphology of chondrocytes with chondrocytic phenotype. These isoforms also decreased the expression of laminin, chondroitin sulfate glycoprotein, and collagen type-I, but they increased production of collagen type-II and did not induce synthesis of fibronectin and S-100 protein. In addition, the strength of cell adhesion on solid surface was reduced by manipulated TGF-β. Only manipulated form of TGF-β1 and 2 could increase the proliferation rate. Manipulation of TGF-β did not up regulate the expression of integrin-β1 in planar culture system. The implications of this R&D work are that the manipulation of TGF-β by combination of TGF-β1, 2, and 3 can be utilized in production of superficial zone of cartilage and perichondrium. The collagen, fibronectin and hyaluronic acid could be recruited for the fabrication of a biodegradable scaffold that promotes chondrocyte growth for autologous chondrocyte implantation or for formation of cartilage.