L’angiogenèses par bourgeonnement est associée à une réorganisation majeure de la matrice extracellulaire (MEC). Nous avons déjà démontré que la lysyl oxydase-like 2 (LOXL2), une enzyme responsable du crosslinking de la MEC, régule la formation de vaisseaux intersomitiques dans les embryons de poisson zèbre et de capillaires en hydrogels 3D. Dans ce manuscrit, nous avons examiné les mécanismes impliqués dans cette régulation. Nous avons constaté l’association intracellulaire de LOXL2 avec la fibronectine et le collagène IV, avant d’être incorporée dans des structures fibrillaires dès l’exocytose. De plus, l’inhibition de l’expression de LOXL2 entraine des défauts de déposition de la MEC et diminue sa rigidité, inhibant secondairement la maturation des structures d'adhésion cellulaire. Alors que LOXL2 n‘est pas nécessaire pour la formation de capillaires dans un modèle 2D sur MEC de fibroblastes, les défauts de déposition de MEC sont corrélés à l'inhibition de formation des capillaires en hydrogel 3D. Ni l’addition de LOXL2 exogène, ni l’augmentation de la rigidité des hydrogels ne compense la perte d’expression de LOXL2. Enfin, nous avons pu montrer que ni l'activité catalytique ni le domaine catalytique de LOXL2 ne sont essentiels pour la formation de capillaire dans le poisson zèbre et dans les hydrogels et pour l’assemblage du collagène IV par des cellules endothéliales. L’ensemble de ces données suggère donc que les domaines SRCR de LOXL2 exprimés par des cellules endothéliales régulent l’échafaudage de fibronectine et de collagène IV dans la MEC qui est nécessaire à la formation de capillaires. / Sprouting angiogenesis is associated with major extracellular matrix (ECM) remodelling, consisting in both degradation of the microenvironment and generation of a new basement membrane. We have previously reported that lysyl oxidase-like 2 (LOXL2), an enzyme responsible for ECM crosslinking, regulates formation of intersomitic vessels (ISV) of zebrafish embryos and of capillaries in 3D hydrogels. In this manuscript we investigated the mechanisms involved. We found that LOXL2 associates with fibronectin and collagen IV intracellulary before direct incorporation in fibrillar structures of the ECM upon exocytosis. In addition, silencing LOXL2 demonstrated its involvement in ECM deposition as both composition and stiffness of the ECM were affected, which subsequently altered maturation of cell adhesion structures. Whereas LOXL2 is not required for formation of capillaries on top of a fibroblast monolayer, in a 2D assay, ECM defaults were associated with altered formation of capillaries in 3D hydrogels.Neither addition of exogenous LOXL2, nor increasing the stiffness of hydrogels could restore capillary formation. Moreover, we could show that neither the catalytic activity nor the catalytic domain were required for capillary formation in vivo and in 3D hydrogels, and for collagen IV deposition by endothelial cells. Altogether, these data suggest that the SRCR domains of LOXL2 expressed by endothelial cells regulate 3D capillary morphogenesis through scaffolding of fibronectin and collagen IV in the ECM.

Background: Tissue engineering and its contribution to regenerative medicine has advanced through the years. It has proven its efficacy especially in the treatment of advanced full thickness burn wounds. Tissue engineering is the synergy between biology and engineering. This fairly young science has one common goal and that is to regenerate new tissue. Various commercially available products have appeared on the market and this due to the ground-breaking work of many. One such well known product is Integra® which is the brain child of Yannas and Burke. This is a collagen-glycosaminoglycan copolymer which serves as a bioactive regeneration template or extracellular matrix analogue. Advanced wound healing is promoted along with the prevention of scar tissue formation and consequent contractures. Aims:</p This study provides an extensive review on the development of this dermal regeneration matrix and also aims to develop an equivalent product. Attention will be paid to: the biological building blocks and the motivation for their use; the essential production steps; and the final processing required in order to deliver a sterile product. Materials and Methods: A collagen and chondroitin 6-sulphate coprecipitate was prepared and subjected to either controlled or uncontrolled freezing. The frozen slurry was dried under vacuum for 17 hours after which each sample was coated with a thin silicone film. Glutaraldehyde crosslinking followed after which the product was thoroughly rinsed. The packaged products were then subjected to terminal sterilisation via gamma irradiation under various conditions. Various tests were conducted to evaluate the newly formed regeneration matrices and included scanning electron microscopy, enzymatic degradation by collagenase, and a cytotoxicity assay. Scanning electron microscopic analysis was done in order to reveal the adequacy of the scaffold architecture. Collagenase degradation of the scaffolds was used to project the rate of degradation of each template. Integra® served as the gold standard for each test. Quantifiable data was statistically analysed and any comparison made included the calculation of means, standard deviations and p-values (confidence interval of 95%). Results: Results indicated that highly porous bioactive tissue engineering matrices were obtained by either controlled freezing or uncontrolled freezing. The average pore diameter of the most homogenous scaffolds ranged between 52.47 and 136.44 µm with a mean of 87.34 µm. These templates were formed by using a 0.5% collagen concentration and a controlled freeze rate of 0.92 °C/min. Uncontrolled freezing (1.3 °C/min) of a 0.5% collagen concentration resulted in the formation of an irregular scaffold with an average pore diameter of 174.08 µm. It was found that the architecture of the most equivalent scaffold compared well with that of Integra® with p = 0.424. Scaffolds prepared using higher collagen concentrations (1.0%) and controlled freezing resulted in dense sponges with average pore diameters of 56.51 µm. Statistical analysis upon comparison indicated a significant difference p = 0.000 in the micro architecture. The rate of degradation of the most equivalent scaffold was 1.9 times that of Integra®. This implicates that the crosslinking was insufficient and due to one of the following: poor collagen quality; method of crosslinking; and degradation due to terminal sterilization. The rate of scaffold degradation can be extended, either by additional crosslinking or the prevention of degradation induced by irradiation. Temperature vacuum dehydration crosslinking through esterification or amide formation can be used as an initial crosslinking method in further studies. This form of crosslinking will complete the conventional glutaraldehyde crosslinking that reacts with the free amine groups of lysine or hydroxylysine of the protein backbone of collagen. It should be stressed that the determination of an in vivo degradation rate, in the form of an animal study, will aid to confirm the efficacy of the biologically active regeneration matrix. / Dissertation (MSc)--University of Pretoria, 2008. / Anatomy / unrestricted

La matrice extracellulaire (MEC) constitue une source de balises moléculaires qui guident les axones moteurs en direction de leur cible musculaire. Le collagène XV (COLXV) est un collagène associé aux lames basales qui est codé par deux paralogues chez le poisson zèbre, col15a1a et col15a1b. Au cours de ma thèse, nous avons déterminé le patron d’expression du second paralogue col15a1b et caractérisé sa fonction in vivo au cours du développement du poisson zèbre. Dans le tronc, col15a1b est spécifiquement exprimé par les précurseurs du muscle lent qui sont la source d’un grand nombre de molécules de la MEC constituant le chemin des axones moteurs en croissance. Grâce à des anticorps spécifiquement dirigés contre COLXV-B nouvellement générés, nous avons montré que COLXV-B balise la trajectoire des axones moteurs. Des expériences de perte et de gain de fonction ont montré que l’expression et l’organisation extracellulaire de col15a1b dépend des voies de signalisation Hedgehog et unplugged/MuSK respectivement. L’inhibition de l’expression de col15a1b provoque principalement un arrêt de croissance ou des erreurs de trajectoire des axones des motoneurones primaires et secondaires au niveau du point de sélection des trajectoires. Ce défaut d’innervation s’accompagne d’une atrophie musculaire et d’un comportement de nage anormal des embryons en réponse à une stimulation. La conservation de la synthénie, la similarité du patron d’expression de col15a1b et COL15A1 pourrait avoir une fonction identique chez l’humain et représenter un gène candidat pour les maladies neuromusculaires / The extracellular matrix (ECM) provides positional information to guide motoneuron axons toward their muscle target. Collagen XV is a basement membrane component encoded by two paralogs in zebrafish, col15a1a and col15a1b. My PhD project consisted in the characterization of the expression pattern of the col15a1b paralog during development and in the analysis of the in vivo function of this paralog in developing zebrafish embryos. Interestingly, we showed that col15a1b paralog is expressed by slow muscle precursors that represent an important source of the ECM path. Using newly generated antibodies to collagen XV-B (COLXV-B), we found that COLXV-B paves the trajectory of motor axons. Loss and gain of function experiments showed that col15a1b expression and extracellular organization depends respectively on Hedgehog and unplugged/MuSK signaling. Col15a1b knockdown weakly affected slow muscle differentiation but provoked primary and secondary motoneuron axons truncation or pathfinding errors at the choice point where pathway selection takes place. This resulted in muscle atrophy and compromised swimming behavior. Our data identified an unexpected role for COLXV-B as an unplugged/MuSK-dependent cue that paves the axonal motor path to guide the decision of axons at the choice point. The conserved syntheny, the broad expression pattern of col15a1b similar to COL15A1 ortholog and the conservation of the primary sequence of COLXV-B with the mammalian counterparts suggested that the human protein COLXV could display similar function and represent a gene candidate for neuromuscular disorders

Les muscles sont des structures très organisées qui nous permettent d’effectuer un grand nombre de fonctions. Ils sont constitués de cellules musculaires mais aussi de tissus conjonctifs qui comprennent à la fois des cellules et la matrice extracellulaire. Les interactions entre les cellules musculaires et le tissu conjonctif sont cruciales pour la physiologie du muscle. Le collagène VI (COLVI) est une molécule hétérotrimérique ubiquitaire située dans les tissus conjonctifs, qui est impliquée dans un grand nombre de processus biologiques. Les trimères de COLVI sont composés de 2 chaines dites “courtes” et d’une chaine “longue”. Chez les mammifères, il existe à ce jour, 6 chaines COLVI (deux courtes (α1-2(VI) et 4 chaines longues (α3-6(VI)). Peu de choses sont encore connues à propos de l’assemblage des chaines les plus récemment décrites α4-6(VI) avec les chaines courtes ainsi qu’une la potentielle compensation entre les différentes chaines longues. De plus, chez l’homme, un déficit en α1-3(VI) du fait de mutations dans les gènes correspondants COL6A1-3 conduit à un spectre de maladies neuromusculaires appelées myopathies liées au COLVI. Pendant ma thèse, je me suis intéressée au COLVI durant le développement du poisson-zèbre, un modèle pertinent pour l’étude de maladies neuromusculaires. Dans la première partie de mon travail, j’ai identifié 2 orthologues des chaines α4-6(VI) chez le poisson-zèbre grâce à des études bio-informatiques. Du fait de leur plus grande homologie avec la chaine α4(VI) murine, nous les avons nommés col6a4a et col6a4b. Pour mieux comprendre les rôles des protéines correspondantes, j’ai créé des embryons de poissons-zèbres déficients en COLVI en utilisant l’approche transitoire par oligo morpholino antisens (MOs). Nous avons dessiné des MOs ciblant des sites d’épissage des pré-messagers col6a2, col6a4a et col6a4b, provoquant un saut d’exon et conduisant à un stop prématuré (PTC). J’ai observé une forte diminution des transcrits ciblés. Tous les embryons injectés (morphants) ont présenté des phénotypes morphologiques macroscopiques qui ont conduit à des défauts fonctionnels. Ces phénotypes ont été confirmés au niveau ultra-structural par microscopie électronique. Toutefois, l’analyse de la croissance des motoneurones a permis de mettre en évidence des différences entre ces morphants. Par la suite, j’ai voulu créer deux types de lignées transgéniques, pour pouvoir à la fois étudier le déficit en COLVI à plus long terme (grâce à l’utilisation de Zinc Finger Nucleases) et tester des approches de cribles pharmacologiques (lignée transgénique col6a2 contenant un PTC, fusionné à la GFP). J’ai effectué les clonages nécessaires à l’obtention des différentes constructions, et ces dernières ont été testées in vitro pour validation, lorsque cela était possible. Malheureusement, du fait des forts taux de mortalité in vivo dans les deux cas, nous avons dû nous résoudre à arrêter ces projets. En parallèle, ma connaissance du modèle poisson-zèbre m’a donné l’opportunité, dans le cadre d’une collaboration avec l’équipe de Denis Furling, d’aborder une autre problématique. Ce groupe, qui travaille sur la Dystrophie Myotonique de type 1 (DM1), s’est intéressé à la réexpression d’une isoforme fœtale de la dystrophine retrouvée chez les patients DM1 et à sa possible implication dans la pathologie. L’isoforme fœtale diffère de la forme adulte notamment par l’exclusion de l’exon 78, conduisant à un changement de cadre de lecture et un changement dans la partie 3’ de l’ARN de la dystrophine. Nous avons montré que le maintien de l’isoforme fœtale de la dystrophine était délétère pendant le développement du poisson-zèbre, puisque ces embryons ont présenté un phénotype macroscopique dépendant de la dose de MO injectée ainsi que des troubles de la mobilité. / Muscles are highly organized structures that allow us to perform many functions. They are made from muscular cells but also surrounding tissues that comprise both cells and extracellular matrix. The interactions between them are crucial for the muscle physiology. Collagen VI (COLVI) is a heterotrimeric protein, ubiquitously expressed in connective tissues. It plays multiple biological roles in the maintenance of structural integrity, cellular adhesion, migration and survival. COLVI trimers are formed by the assembly of 2 “short” chains and 1 “long” chain. To date, six COLVI chains are recognized in mammalians with 2 short (α1-2(VI)) and 3 long (α3-6(VI)) chains. Little is known regarding the possible assembly of the newly characterized α4-6(VI) polypeptides with the short chains, and a putative functional compensation between the different long chains. Furthermore, in humans, deficiency in α1-3(VI) due to mutations in the COL6A1-3 genes causes a heterogeneous group of neuromuscular disorders collectively termed COLVI-myopathies. During my Ph.D, I got interested in COLVI during the development of zebrafish, a relevant model of neuromuscular disorders. In the first part of my work, I identified 2 orthologs of the α4-6(VI) chains in zebrafish thanks to bio-informatics studies. In light of their stronger homology with the mammalian α4(VI) chain, we named the genes encoding the novel chains col6a4a and col6a4b. To further unveil the roles of the corresponding proteins, we created COLVI deficient zebrafish embryos using a morpholino antisense oligonucleotides approach (MO) . We chose to design MOs that block splicing of col6a2, col6a4a and col6a4b, thereby creating premature termination codons. As expected, the targeted transcripts levels were drastically reduced, likely due to degradation by the nonsense mediated RNA decay. All morphant embryos presented macroscopic and morphologic phenotypes that overall resulted in functional muscle defects: altered muscle structure detected by birefringence analysis and impaired motility upon touch-evoked escape test. These alterations were confirmed at the ultra-structural level by electron microscopy. Nevertheless, some phenotypical specificities were uncovered between the different col6a2, col6a4a and col6a4b morphants, with the discovery of axon outgrowth defects. In a second part, we wanted to create stable zebrafish lines to study COLVI deficiency at later stages using Zinc Finger Nucleases (ZFN) and to be able to carry out pharmacological screenings with a transgenic line containing col6a2 with a premature codon (PTC) fused to the GFP. I performed clonings to obtain the different constructs. When possible, constructs were tested in vitro. Unfortunately, due to high mortality in vivo in both cases, we had to interrupt these projects. In parallel, my knowledge of the zebrafish model gave me the opportunity to be part of another project, in collaboration with the team of Denis Furling...

L’obésité maternelle, dont la prévalence ne cesse d’augmenter, est associée à de nombreux troubles de l’accouchement, tels que des dépassements de terme à l’origine d’une augmentation du taux de césariennes. Ces troubles pourraient, en partie, s’expliquer par une concentration plasmatique de leptine plus élevée chez les femmes enceintes obèses ainsi que par les effets inhibiteurs, démontrés in vitro, de cette adipokine sur la contractilité myométriale. Au moment de l’accouchement, la transition phénotypique du myomètre d’un état de quiescence utérine à un état contractile est une étape clé indispensable à la mise en route du travail. Elle est associée à une activation de l’apoptose des cellules myométriales ainsi qu’à un remodelage de la matrice extracellulaire utérine. Le but de notre travail était d’étudier la capacité de la leptine à moduler l’apoptose et le remodelage myométriaux induits par le lipopolysaccharide (LPS).Les échantillons de myomètre ont été prélevés lors de césariennes réalisées avant la mise en route du travail, à la maternité du CHU de Dijon. Les effets de la leptine ont été évalués après incubation des explants myométriaux pendant 48 heures avec du LPS (10 µg/ml) avec ou sans leptine (de 10-10 à 10-8 M).Nos résultats ont démontré la capacité de la leptine à inhiber, de façon concentration-dépendante, l’apoptose induite par le LPS en diminuant l’expression des protéines pro-apoptotiques (caspase-3 clivée, BAX) et en augmentant celle du médiateur anti-apoptotique BCL2. Cet effet anti-apoptotique de la leptine dans le myomètre gestant était associé à l’activation de la voie de signalisation ERK1/2. De plus, nos résultats ont montré que la leptine était également capable de s’opposer, de façon concentration-dépendante, à la dégradation du collagène de la matrice extracellulaire myométriale induite par le LPS. Cet effet était associé à l’inhibition de l’activation et de la surexpression des métalloprotéinases MMP2 et MMP9 induites par le LPS.Ce travail a permis d’approfondir les connaissances sur le rôle de la leptine dans la régulation de l'activité du myomètre. Nos résultats suggèrent que les troubles de l’accouchement observés chez les femmes obèses résulteraient de l’inhibition de l’apoptose et du remodelage myométriaux par la leptine, en plus de l’inhibition de la contractilité utérine déjà décrite. / Maternal obesity is associated with a wide spectrum of delivery disorders, such as delayed or post-term delivery, that might be explained partly by the increase in plasma leptin levels in obese women, as leptin inhibits in vitro myometrial contractility. Delivery involves uterine apoptosis and remodelling of the extracellular matrix, via the activation of matrix metalloproteinases (MMP). This study was aimed to assess the role of leptin on human myometrium, by studying the interaction of leptin with lipopolysaccharide (LPS)-induced apoptosis and degradation of myometrial collagen.Myometrial biopsies were obtained from women undergoing caesarean delivery before labour onset. The effects of leptin on myometrial apoptosis and remodelling were assessed by incubating the strips for 48h with LPS (10 µg/ml) alone or with leptin (from 10-10 to 10-8 M).Leptin prevented LPS-induced apoptosis, in a concentration-dependent manner, by down-regulating cleaved caspase-3, BAX and up-regulating BCL2 expression. This effect was specifically mediated through leptin receptors stimulation followed by ERK1/2 signalling pathway activation. Leptin prevented, in a concentration-dependent manner, an LPS-induced decrease in myometrial collagen content, and this effect was associated with a decrease in MMP2 and MMP9 activity and overexpression. These effects of leptin were abolished by pre-treatment with a selective leptin receptor antagonist. These results suggest new potential pathways involved in delivery disorders of obese women and propose a role for leptin-induced inhibition of myometrial apoptosis and extracellular matrix remodelling in the development of such disorders.

Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve graft is still the first choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. Among adult stem cells, adipose-derived stem cells (ASC) are a useful tool in regenerative medicine as they can be induced towards multiple mesodermal and nonmesodermal lineages, being recently differentiated into cells showing Schwann cell-like morphology, glial cell markers and increased neurotrophic potential. The first two chapters of this work describe in vivo applications of Schwann cell-like differentiated ASC (dASC), seeded into biodegradable nerve guides made of fibrin, investigating both brief (2 weeks) and long (4 months) term effects on the regenerating nerves. Comparison was carried out with similarly differentiated bone marrow mesenchymal stem cells (dMSC), Schwann cells (SC)and empty fibrin conduits, as well as with autologous nerve grafts. Regeneration was evaluated in a 1cm gap total axotomy sciatic nerve injury model on rats. Results showed that dASC could improve regeneration distance in a similar manner to other regenerative cells inthe brief term. This effect was maintained and strengthened in the long term, where nerve morphology, spinal motoneurons regeneration, protection from muscle atrophy and electrophysiological performances of regenerated nerves were analysed. dASC positive effects lasted in the long term with functional results comparable to the autologous nerve grafts, which served as controls. The third chapter focuses on the possibility to further improve dASC regenerative performances using fibronectin and laminin, two key extracellular matrix (ECM) molecules involved in nerve regeneration, with the future aim to optimize cell host, directional cues and neurotrophism of tissue engineered conduits. Fibronectin and laminin protected dASC from stress-induced cell death in vitro, significantly increasing cell adhesion and viability. Laminin significantly improved neurotrophic properties of dASC enhancing neurite outgrowth of both primary sensory neurons and NG108-15 neurons co-cultured with dASC, suggesting a further activation of the neurotrophic effect of dASC by ECM molecules. These improved effects were increased when a direct contact was established between the laminin substrate, dASC and neurons, suggesting a primary role of laminin in contact signalling, finally boosting the neurotrophic potential of dASC. Further studies will be needed to clarify the interactions between dASC and the complexniche of peripheral nerve regeneration, including the ECM molecules. However, the neurotrophic potential of dASC expressed in both in vitro and in vivo experiments opens wide perspectives in tissue engineering applications among new methods to enhance peripheral nerve repair.

Orientador: Edson Rosa Pimentel / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-26T15:25:06Z (GMT). No. of bitstreams: 1 Vieira_CristianoPedrozo_D.pdf: 3245048 bytes, checksum: 0556c35183a4503cef8427390d086781 (MD5) Previous issue date: 2015 / Resumo: Nutrição terapêutica é a administração de alguns nutrientes, em doses maiores que as necessidades alimentares diárias que podem prevenir deficiências orgânicas e atuar como agentes farmacológicos. A glicina apresenta amplos efeitos benéficos em processos inflamatórios e tumorais. O Chá verde feito de folhas e brotos da planta Camellia sinensis, é a segunda bebida mais consumida em todo mundo. O interesse econômico e social tem ganhado espaço no mercado e atualmente seu consumo faz parte da rotina diária de muitas pessoas que utilizam essa bebida como uma finalidade terapêutica. O Chá verde possui propriedades antimutagênicas, antidiabéticos, antiinflamatórias, antioxidante, antimicrobial e hipocolesterolêmica. A tendinite é reconhecidamente um problema clínico que motiva a comunidade científica a buscar tratamentos que auxiliem no restabelecimento das propriedades funcionais dos tendões. O presente estudo investigou o efeito do chá verde e ou da ração rica em glicina após 7 e 21 dias da indução da tendinite com colagenase. Ensaios bioquímicos, moleculares, morfológicos e biomecânicos foram desenvolvidos. Além disso, tenócitos em cultura foram tratados com glicina após inflamação induzida por TNF-?. Nossos ensaios in vivo mostraram altas concentrações de hidroxiprolina e glicosaminoglicanos no grupo glicina e chá em 21 dias de tratamento. Nos ensaios biomecânicos os grupos chá verde e dieta de glicina em 21 dias suportaram maiores cargas biomecânicas antes da ruptura. Além disso, uma melhor organização das fibras de colágeno foi observada no grupo chá verde em 7 dias. Análises bioquímicas e moleculares da junção miotendínosa mostraram que a inflamação instalada na região osteotendinea pode provocar alterações significativas nesse local. Marcantes alterações foram notadas nas metaloproteínases (MMP) tais como MMP-2, MMP-8 e MMP-9 em animais com tendinite tratados ou não com chá verde e glicina. No estudo in vitro, tenócitos extraídos a partir de tendão de Aquiles foram tratados com TNF-?, seguindo ou não de tratamento com glicina em meio de cultura. Antes e após 24 horas da inflamação foi adicionado glicina. Tenócitos inflamados e tratados com glicina mostraram expressão de colágeno tipo I próxima aos grupos tratados com glicina previamente e depois da inflamação quando comparado ao grupo controle. Todos os grupos tratados com glicina mostraram menor expressão de MMP-2. A atividade da MMP-9 foi alta apenas no grupo tratado com glicina em 48 horas. A concentração de ácido urônico foi menor no grupo tratado com glicina 24 horas após a inflamação. No ensaio de migração celular, resultados em 24 horas de tratamento foram similares ao grupo controle. Em geral, tanto a glicina quanto o chá verde influenciam na síntese dos componentes do tendão, melhoram a organizaçao das fibras colagênicas, aumentam a resistência a cargas do tendão inflamado e consequentemente aceleram o processo de remodelamento após indução da tendinite. Além disso, o tratamento com glicina em cultura de tenócitos mostrou uma reorganização eficiente da matriz extracelular, corroborando com os resultados encontrados in vivo / Abstract: Therapeutic nutrition is the administration of some nutrients, in higher doses than those recommended for the daily food needs that can prevent dysfunctions and act as pharmacological agents. Glycine has large beneficial effects in inflammatory and tumor processes. Green tea made from leaves and buds of the Camellia sinensis plant, is the second most consumed beverage in the world. The economic and social interest has gained space in the market and currently its consumption is part of the daily routine of many people who use this drink as a therapeutic purpose. Green tea has antimutagenic, antidiabetic, anti-inflammatory, antioxidant, antimicrobial and hypocholesterolemic properties. Tendinitis is recognized as a clinical problem that motivates the scientific community to investigate treatments that help in restoring the functional properties of tendons. The present study investigated the effect of green tea and/or diet rich in glycine after 7 and 21 days of tendinitis collagenase-induced. Biochemical, molecular, morphological and biomechanical tests were developed. Furthermore, tenocytes in culture were treated with glycine after inflammation induced by TNF-?. Our tests in vivo showed high concentrations of hydroxyproline and glycosaminoglycans in glycine and green tea group in 21 days of treatment. In biomechanical assay, green tea and glycine diet groups in 21 days showed a high biomechanical loads bore before rupture. In addition, better organization of collagen fibers was observed in green tea group in 7 days. Biochemical and molecular analyzes of myotendinous junction showed that the inflammation installed in osteotendinious region can cause significant change in that region. Remarkable changes were noted in metalloproteinases (MMP) such as MMP-2, MMP-8 and MMP-9 in animals with tendinitis treated with or without glycine and green tea. In the in vitro study, tenocytes from Achilles tendon were treated with TNF-?, or not following treatment with glycine in the culture medium. Before and 24 hours after inflammation was added glycine. Tenocytes inflamed and treated with glycine showed expression of collagen type I close to the treated groups with glycine previously and after the inflammation when compared to the control group. All treated groups showed less glycine MMP-2 expression. The activity of MMP-9 was high only in the group treated with glycine for 48 hours. In the cell migration assay results in 24 hours of treatment were similar to the control group. In general, both glycine and green tea influenced the synthesis of the tendon components, improve the organization of the collagenous fibers, increase the load resistance of the inflamed tendon and consequently accelerate the remodeling process after inducing tendinitis. In addition, the treatment with glycine in tenocytes culture showed efficient reorganization of the extracellular matrix, confirming the results found in vivo / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

O câncer de mama representa importante problema de saúde pública. O microambiente tumoral tem participação no câncer. Peptídeos derivados da laminina estão envolvidos com progressão tumoral. O peptídeo C16 (KAFDITYVRLKF), da cadeia gama-1 da laminina, estimula adesão, migração e invasão celular, metástase e angiogênese. Para avaliar o efeito deste peptídeo na expressão gênica de células de câncer de mama (MDA-MB-231), células foram tratadas com C16 ou peptídeo controle (FKLRVYTIDFAK) por 24 horas. Após tratamento, a expressão gênica foi avaliada por microarray. C16 regulou a expressão de 80 genes em células MDA-MB-231, incluindo genes associados ao câncer. Os genes FGFR3, GPNMB e SPOCK1 tiveram suas expressões aumentadas após tratamento com C16, como confirmado por PCR quantitativo. Ensaios de invasão em câmaras de Boyden também indicam que C16 estimula invasão de células MDA-MB-231, porém C16 não mostrou efeito sobre proliferação e apoptose. Nossos dados sugerem que o peptídeo C16 regula expressão gênica e estimula invasão de células de câncer de mama MDA-MB-231. / Human breast cancer constitutes a worldwide health care problem. During cancer progression, tumor cells are engaged in an interplay with their microenvironment. Studies have shown that peptides derived from laminin are involved in tumor progression. Among them, C16 (KAFDITYVRLKF), derived from laminin gamma-1 chain, is a cell-adhesive peptide that increases cell migration, invasion, metastasis and angiogenesis. This prompted us to analyze whether C16 would regulate gene expression in human breast cancer cells (MDA-MB-231). Cells were treated with C16 or scrambled peptide control (FKLRVYTIDFAK) for 24 hours and gene expression was analyzed by microarray. Eighty genes were regulated by C16, including genes associated with cancer. Among them, FGFR3, GPNMB and SPOCK1 expression was increased by C16, as confirmed by qPCR. C16 also increased MDA-MB-231 cell invasion. However, no effect on cell proliferation and apoptosis was observed. Concluding, our data suggest that C16 regulates gene expression and enhances invasion of metastatic MDA-MB-231 breast cancer cells.

Neste estudo avaliou-se os efeitos do diabetes mellitus (DM) sobre dois sistemas: glândula parótida de ratos e células cultivadas in vitro. Foram avaliados respectivamente a composição da matriz extracelular e a migração de células expostas a elevada concentração de glicose. Na parótida observou-se aumento de colágenos III, IV e V, laminina e fibronectina, mediado por TGFb2. Em células isoladas observou-se que a glicose dificultou a polarização celular, reduziu a velocidade e direcionalidade de migração, reduziu a persistência e estabilidade das protrusões celulares e a maturação de adesões. Estas alterações estão relacionadas à ativação da GTPase Rac1, dependente de estresse oxidativo. Este estudo sugere, pela primeira vez, que: 1) a hipofunção salivar pode envolver um espessamento da lâmina basal de capilares e parênquima por mecanismos previamente observados em outros orgãos-alvo de complicações diabéticas e 2) que a glicose exerce um efeito direto sobre a migração celular, fator que pode contribuir para a cicatrização deficiente em indivíduos diabéticos. / In this study we evaluated the effects of DM on two different systems: the rat parotid gland and in vitro cultured cells. Extracellular matrix composition and the migratory behavior of cells exposed to a high glucose concentration (HG) were evaluated, respectively. In the parotid, DM led to an increase in collagens III, IV and V, laminin and fibronectin, through a TGFb2-dependent mechanism. In cultured cells, HG impaired cell polarization, reduced migration velocity and directionality, reduced the persistence and stability of protrusive cellular processes, as well as adhesion maturation. These effects were related to Rac1 GTPase activation, dependent on the oxidative stress promoted by HG. This study suggests, for the first time, that: 1) salivary hypofunction in DM might involve the thickening of capillary and parenchyma basal lamina, through mechanisms already described in other target organs for diabetic complications and 2) that glucose directly impairs cell migration, and this effect may contribute to the chronic wound healing observed in diabetic patients.

O câncer de mama é no Brasil o segundo maior causador de morte entre mulheres. Os hormônios sexuais estão dentre os vários fatores indutores ou promotores da carcinogênese. ADAMTS (uma desintegrina e metaloproteinase com domínios trombospondina) é uma enzima Zn2+/Ca2+dependente. Avaliamos a influência dos hormônios na expressão e localização da ADAMTS-1 em 3 linhagens de mama. qPCR demonstrou que a progesterona estimulou o aumento de mRNA de ADAMTS-1 na MCF-10A e na MDA-MB-231, o tratamento com estrógeno e progesterona estimulou a diminuição. No Western blot observamos nas linhagens MCF-10A e MCF-7 que os hormônios tendem a aumentar os níveis de ADAMTS-1, e o estrógeno estimulou uma acentuada secreção em MCF-7. Na linhagem MDA-MB-231, os tratamentos demonstraram uma tendência a diminuir os níveis de ADAMTS-1 intracelular. Na imunofluorescência e Western blot observamos a predominância de ADAMTS-1 nuclear. Os resultados sugerem que os hormônios regulam a expressão de ADAMTS-1 nas células normais e tumorais, e que está predominantemente presente no núcleo celular. / Breast cancer is the second largest cause of death among women in Brazil. Sex hormones are one of the several inducers factors or cancer promoters. ADAMTS (a disintegrin and metaloproteinase with thrombospondin motifs) are dependent on Zn2+/Ca2+ enzymes. We evaluated influence of hormones on ADAMTS-1 levels and localization in three different breast cell lines. qPCR showed that progesterone stimulated an increase of ADAMTS-1 mRNA in MCF-10A, however, in MDA-MB-231, the treatment by estrogen and progesterone decreased levels. Western blot analysis showed a tendency to increased ADAMTS-1 levels in MCF-10A and MCF-7 due to the hormone treatment. Treatment by estrogen led to a marked secretion in MCF-7. In MDA-MB-231 the treatment showed a tendency to decreased intracellular ADAMTS-1 protein levels. Immunofluorescence and Western Blot we observed ADAMTS-1 predominant in the nucleus. Results suggest that sex hormones regulate the ADAMTS-1 expression in normal and tumoral breast cells, ADAMTS-1 is predominant in the cellular nucleus.