Τα αγγειακά λεία μυικά κύτταρα (ΑΛΜΚ) αποτελούν το κυρίαρχο στοιχείο του μέσου χιτώνα των αιμοφόρων αγγείων, ενώ συμμετέχουν ενεργά και στο σχηματισμό και την ωρίμανση του καρδιαγγειακού συστήματος. Η δομή τους εξυπηρετεί την εκτέλεση της σημαντικότερης λειτουργίας τους, που είναι η συστολή. Αξιοσημείωτο χαρακτηριστικό των αγγειακών λείων μυικών κυττάρων αποτελεί η φαινοτυπική τους πλαστικότητα, δηλαδή η ικανότητα στροφής από το συσταλτικό σε έναν περισσότερο συνθετικό φαινότυπο, που λαμβάνει χώρα υπό προϋποθέσεις. Οι αλληλεπιδράσεις με τα υπόλοιπα κυτταρικά στοιχεία του τοιχώματος των αρτηριών και των έμμορφων συστατικών του αίματος, αλλά και η φαινοτυπική πλαστικότητα καθιστούν καθοριστικό το ρόλο των αγγειακών λείων μυικών κυττάρων στην παθογένεια της αθηροσκλήρωσης. / Vascular smooth muscle cells (VSMCs) comprise the main element of the tunica media of blood vessels, while they actively participate in the formation and maturation of the cardiovascular system. Their structure serves their basic function, which is contraction. An interesting feature of vascular smooth muscle cells is their phenotypic plasticity, the ability to shift from a contractile to a more synthetic phenotype, under certain conditions. The interaction with other cellular elements within the vascular wall or in the bloodstream, as well as their phenotypic plasticity, give vascular smooth muscle cells a decisive role in the pathogenesis of atherosclerosis.

Thesis (Ph. D.)--University of Sydney, 2009. / Title from title screen (viewed Aug. 11, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Discipline of Pharmacology, Faculty of Medicine. Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.

Phosphatidylinositol 5-phosphate (PtdIns5P) is the least well-characterised member of the phosphoinositide family of essential regulatory phospholipids. PtdIns5P levels are altered within cells in response to a number of stimuli and evidence is accumulating to suggest that it possesses important functions in cellular signalling. However, the physiological role of this lipid remains imperfectly understood. Previous studies have shown that PtdIns5P is elevated in adipocytes in response to insulin, and microinjection of PtdIns5P into these cells promotes plasma membrane insertion of the insulin-regulated glucose transporter GLUT4 (Sbrissa et al., 2004). This finding suggests a potential role of PtdIns5P as a mediator in insulin-stimulated glucose uptake, a process essential for efficient glucose homeostasis. As approximately 75% of postprandial glucose disposal is carried out by skeletal muscle, it is important to investigate the role of PtdIns5P in the response of this tissue to insulin. Therefore, this work has used differentiated myotubes of the rat muscle cell line, L6, to explore the effects of altered PtdIns5P levels on insulin-stimulated glucose uptake. This cell model had not been previously used in the laboratory so it first required characterisation. Here insulin is shown to stimulate a transient increase of PtdIns5P in L6 myotubes, indicative of a signalling role in response to insulin. This project developed several tools to further investigate this potential role for PtdIns5P in the insulin response of myotubes. One such development was the successful overexpression of the PtdIns5P 4-kinase PIP4KIIalpha in these cells, which was able to abolish the insulin-stimulated PtdIns5P rise. This correlated with a loss of insulin-stimulated glucose uptake (upon PIP4KIIalpha expression). Interestingly, artificial elevation of PtdIns5P in L6 myotubes increases glucose uptake in the absence of stimulation. This phenomenon appears to result from the activation of PI3-kinase signalling, as it is abolished by the PI3-kinase inhibitor wortmannin, and involves activation of the PI3-kinase effector Akt. These results are consistent with the idea that insulin-stimulated PtdIns5P production contributes to the robust PI3-kinase/Akt activation necessary for insulin-stimulated glucose uptake in muscle.

Orientador: Hernandes Faustino de Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T10:22:10Z (GMT). No. of bitstreams: 1 Victorio_SheilaCristinadaSilva_M.pdf: 1499738 bytes, checksum: 1208b4b617e591a974a869b7fa20a388 (MD5) Previous issue date: 2007 / Resumo: O crescimento e função prostática dependem da estimulação androgênica e interação epitélio-estroma. Além dos andrógenos, outros fatores interagem com a próstata e são igualmente importantes para sua fisiologia. Sabe-se que os estrógenos exercem um importante papel no desenvolvimento prostático e que, combinados com andrógenos, podem contribuir para o aparecimento de patologias. A insulina é outro hormônio que afeta a atividade destes hormônios sexuais nos tecidos, inclusive na próstata. Os níveis séricos de esteróides sexuais estão intimamente relacionados com a sensibilidade a insulina, embora esta relação ainda seja pouco esclarecida. No estroma prostático, as células musculares lisas são o tipo celular predominante, influenciando a atividade do epitélio por mecanismos parácrinos e modificando a matriz extracelular em situações de remodelação, como no crescimento, na regressão e na invasão tumoral. Sabe-se que estas células apresentam receptores de andrógeno (AR) e que respondem à privação androgênica, alterando sua morfologia. O presente estudo buscou verificar a influência da testosterona, estradiol e insulina sobre a expressão e localização do AR em células musculares lisas da próstata ventral de ratos Wistar cultivadas in vitro. Os resultados mostraram que o estradiol causou alterações nos níveis protéicos, os níveis de RNAm do AR foram pouco afetados e a localização do AR foi predominantemente nuclear independente da dose de estradiol. Os tratamentos feitos com insulina mostraram que a sua presença causou uma queda da expressão da proteína e uma localização predominante nuclear do AR na situação em que os dois hormônios, insulina e testosterona, foram administrados juntamente. Os resultados permitem sugerir que a expressão do AR pode ser modulada por outros fatores como estrógeno e insulina / Abstract: The prostate function and growth depends on the androgenic stimulation and epitheliumstroma interaction. Besides androgens, other factors interact with the prostate and are also important for its physiology. It is known that estrogens exert an important role in prostate development, and combined with androgens they can contribute for the appearance of pathologies. The insulin is another hormone that interacts with these sexual hormones in tissues, and also in the prostate. The serum levels of sexual steroids are closely related with the sensitivity to the insulin, even though this relation is not yet clear. In prostatic stroma, smooth muscle cells are the predominant cell type. They influence the activity of the epithelium through paracrine mechanisms and modify the extracellular matrix in remodeling situations, such as gland growth and regression, and during tumor invasion. It is known that these cells express androgen receptor (AR) and respond to androgen deprivation by modifying its phenotype. The present study was undertaken to verify the influence of testosterone, estradiol and insulin on the expression and localization of the AR in the smooth muscle cells from the Wistar rat ventral prostate cultured in vitro. The results showed that estradiol caused alterations in the AR protein levels, the mRNA level was less affected and AR localization was predominantly nuclear irrespective of the estradiol dose. Insulin treatments caused a decrease in the expression of the protein and a predominant nuclear localization of AR in the presence of testosterone. The results suggest that AR expression and regulation might be modulated by others factors such as estrogen and insulin / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Orientador: Hernandes Faustino de Carvalho / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T18:51:36Z (GMT). No. of bitstreams: 1 Antonioli_Eliane_D.pdf: 2188815 bytes, checksum: f2d0da35f06c89ebb912a05bcce1dc39 (MD5) Previous issue date: 2007 / resumo: As células musculares lisas (CML) são o principal componente do estroma prostático e desempenham um importante papel na manutenção da fisiologia do órgão, atuando na contração durante a ejaculação, na sua remodelação frente a neoplasias e/ou privação androgênica, na produção de fatores parácrinos e na síntese/degradação/reorganização da matriz extracelular, segundo um intrincado mecanismo de comunicação com as células epiteliais. Além disso, tem sido também proposto que a invasão tumoral depende de uma participação ativa das células estromais, inclusas as CML, na produção de metaloproteinases de matriz (MMPs) e/ou seus inibidores dentre outros fatores. O presente estudo investigou a expressão dos marcadores de músculo liso na próstata ventral de ratos após longo período de castração. Em outra frente de investigação foi analisado o efeito do estiramento mecânico no comportamento das CML in vitro. Os resultados obtidos demonstraram que as CML são afetadas pela privação androgênica. Embora demonstrem mudanças morfológicas, estas células expressam marcadores de músculo liso em nível de proteína (a-actina e cadeia pesada da miosina de músculo liso) e de RNAm (smoothelin, sm22 e calponina). Estes resultados suportam a idéia de que CML prostática pode modular o seu fenótipo (contrátil vs. sintético) sem alterar o estado de diferenciação. Sabe-se que a função primária das CML prostáticas está relacionada à contração do órgão e que isto impõe uma deformação mecânica sobre estas células. Por esta razão, resolveu-se investigar se haveria modulação do seu comportamento frente ao estiramento in vitro, sob condições controladas. Foi demonstrado que as CML diminuem a atividade proliferativa em resposta ao estiramento cíclico da mesma forma que ao estiramento estático. Em relação à expressão de proteínas relacionadas à atividade contrátil (a-actina e cadeia pesada da miosina de músculo liso), os resultados obtidos indicam que as CML respondem ao estiramento cíclico com um aumento na concentração destas proteínas o que poderia indicar hipertrofia celular, o que foi confirmado pela quantificação do conteúdo de F-actina por citometria de fluxo. Este efeito não foi observado frente ao estiramento estático. Os dois conjuntos de dados confirmam que as CML apresentam grande versatilidade fenotípica, respondendo de formas diferentes não somente a estímulos hormonais, mas também a variação na demanda funcional / Abstract: Smooth muscle cells (SMC) are the main component of the prostatic stroma and play important roles in the organ physiology, acting on the contraction associated with ejaculation and on the remodeling related to neoplasias or androgen deprivation, on the production of paracrine factors and the synthesis/degradation/reorganization of extracellular matrix components, after an intricate mechanism of intercommunication with epithelial cells. Besides, it has been proposed that tumor invasion depends on the active participation of stromal cells, including SMC, on the production of MMPs and/or their inhibitors among other factors. The present study investigated the expression of smooth muscle markers on the rat ventral prostate after long term androgen deprivation. Another set of experiments were designed to study the effect of mechanical stretching on SMC behavior in culture. The results demonstrated that SMC are affected by androgen deprivation. Even though the SMC exhibited morphological changes, they kept the expression of smooth muscle markers at the protein (SM a-actin and SM-MHC) and mRNA levels (smoothelin, sm22 and calponin). These results reinforce the idea that prostatic SMC modulate their phenotype (contractile vs. synthetic) without compromise the differentiation state. It is well known that the primary function of the SMC is the organ contraction and that it subjects the cells to mechanical deformation. For this reason, it was decided to test whether SMC modulate their behavior in response to mechanical stretching in vitro under controlled conditions. It was demonstrated that both cyclic and static mechanical stretches decrease SMC proliferation. On the other hand, cyclic stretching increased the concentration in SM-MHC and SM a-actin that could be associated with cell hypertrophy. To confirm this hypothesis, the F-actin content was measured through the intensity of FITC-phalloidin labeling by flow cytometry at the single cell level. The results confirmed that cyclic stretching caused a significant increase in cytoskeleton mass, what is compatible with cell hypertrophy. This effect was not observed after static stretching. The two sets of results confirm that SMC exhibit great phenotypical versatility, responding not only to hormonal stimuli, but also to functional demands / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23380号 / 医博第4749号 / 京都大学大学院医学研究科医学専攻 / (主査)教授 山下 潤, 教授 木村 剛, 教授 YOUSSEFIAN Shohab / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

To successfully develop a functional tissue-engineered vascular patch, recapitulating the hierarchical structure of vessel is critical to mimic mechanical properties. Here, we use a cell sheet engineering strategy with micropatterning technique to control structural organization of bovine aortic vascular smooth muscle cell (VSMC) sheets. Actin filament staining and image analysis showed clear cellular alignment of VSMC sheets cultured on patterned substrates. Viability of harvested VSMC sheets was confirmed by Live/Dead® cell viability assay after 24 and 48 hours of transfer. VSMC sheets stacked to generate bilayer VSMC patches exhibited strong inter-layer bonding as shown by lap shear test. Uniaxial tensile testing of monolayer VSMC sheets and bilayer VSMC patches displayed nonlinear, anisotropic stress-stretch response similar to the biomechanical characteristic of a native arterial wall. Collagen content and structure were characterized to determine the effects of patterning and stacking on extracellular matrix of VSMC sheets. Using finite-element modeling to simulate uniaxial tensile testing of bilayer VSMC patches, we found the stress-stretch response of bilayer patterned VSMC patches under uniaxial tension to be predicted using an anisotropic hyperelastic constitutive model. Thus, our cell sheet harvesting system combined with biomechanical modeling is a promising approach to generate building blocks for tissue-engineered vascular patches with structure and mechanical behavior mimicking native tissue.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20801号 / 医博第4301号 / 新制||医||1025(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 松田 道行, 教授 山下 潤, 教授 宮本 享 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

no / Cardiovascular disease is the principal cause of death in patients with type 2 diabetes (T2DM). Exposure of the vasculature to metabolic disturbances leaves a persistent imprint on vascular walls, and specifically on smooth muscle cells (SMC) that favours their dysfunction and potentially underlies macrovascular complications of T2DM. Current diabetes therapies and continued development of newer treatments has led to the ability to achieve more efficient glycaemic control. There is also some evidence to suggest that some of these treatments may exert favourable pleiotropic effects, some of which may be at the level of SMC. However, emerging interest in epigenetic markers as determinants of vascular disease, and a putative link with diabetes, opens the possibility for new avenues to develop robust and specific new therapies. These will likely need to target cell-specific epigenetic changes such as effectors of DNA histone modifications that promote or inhibit gene transcription, and/or microRNAs capable of regulating entire cellular pathways through target gene repression. The growing epidemic of T2DM worldwide, and its attendant cardiovascular mortality, dictates a need for novel therapies and personalised approaches to ameliorate vascular complications in this vulnerable population.

yes / Type 2 diabetes (T2DM) promotes premature atherosclerosis and inferior prognosis after arterial reconstruction. Vascular smooth muscle cells (SMC) respond to patho/physiological stimuli, switching between quiescent contractile and activated synthetic phenotypes under the control of microRNAs (miRs) that regulate multiple genes critical to SMC plasticity. The importance of miRs to SMC function specifically in T2DM is unknown. This study was performed to evaluate phenotype and function in SMC cultured from non-diabetic and T2DM patients, to explore any aberrancies and investigate underlying mechanisms. Saphenous vein SMC cultured from T2DM patients (T2DM-SMC) exhibited increased spread cell area, disorganised cytoskeleton and impaired proliferation relative to cells from non-diabetic patients (ND-SMC), accompanied by a persistent, selective up-regulation of miR-143 and miR-145. Transfection of premiR-143/145 into ND-SMC induced morphological and functional characteristics similar to native T2DM-SMC; modulating miR-143/145 targets Kruppel-like factor 4, alpha smooth muscle actin and myosin VI. Conversely, transfection of antimiR-143/145 into T2DM-SMC conferred characteristics of the ND phenotype. Exposure of ND-SMC to transforming growth factor beta (TGFβ) induced a diabetes-like phenotype; elevated miR-143/145, increased cell area and reduced proliferation. Furthermore, these effects were dependent on miR-143/145. In conclusion, aberrant expression of miR-143/145 induces a distinct saphenous vein SMC phenotype that may contribute to vascular complications in patients with T2DM, and is potentially amenable to therapeutic manipulation.