The Cx43 CT mimetic peptide, αCT1, originally designed to bind to ZO1 and thereby inhibit Cx43/ZO1 interaction, was used as a tool to probe the role of Cx43/ZO1 association in regulation of epithelial/endothelial barrier function. Using both in vitro and ex vivo methods of barrier function measurement, including Electric Cell-Substrate Impedance Sensing(ECIS), a TRITC-dextran transwell permeability assay, and a FITC-dextran cardiovascular leakage protocol involving Langendorff-perfused mouse hearts, αCT1 was found to protect the endothelium from thrombin-induced breakdown in cell-cell contacts. Barrier protection was accompanied by significant remodeling of the F-actin cytoskeleton, characterized by a redistribution of F-actin away from the cytoplasmic and nuclear regions of the cell, towards the endothelial cell periphery, in association with alterations in cellular orientation distribution. In line with observations of increased cortical F-actin, αCT1 upregulated cell-cell border localization of endothelial VE-cadherin, the Tight Junction protein Zonula Occludens 1 (ZO1) , and the Gap Junction Protein (GJ) Connexin43 (Cx43). A ZO1-binding-incompetent variant of αCT1, αCT1-I, indicated that these effects on barrier function and barrier-associated proteins, were likely associated with Cx43 CT sequences retaining ability to interact with ZO1. These results implicate the Cx43 CT and its interaction with ZO1, in the regulation of endothelial barrier function, while revealing the therapeutic potential of αCT1 in the treatment of vascular edema. / Doctor of Philosophy / Endothelial cells make up blood vessels within the heart and regulate the exchange of fluids between the circulation and heart tissue. In many forms of heart disease, the cardiac endothelium is disrupted, resulting in a damaging leakage and buildup of fluids within the heart. This work explores how a small peptide, derived from a naturally occurring molecule, may help to prevent fluid-associated damage to the heart by stabilizing the blood endothelium.

No description available.

Chez les rongeurs rendus obèses par un régime hyper-lipidique, un changement du microbiote est associé à une altération de la perméabilité intestinale, augmentant le passage d’antigènes alimentaires ou bactériens et contribuant à une inflammation chronique de bas grade et une insulinorésistance. Cependant chez l’homme, les modifications de perméabilité intestinale, son impact sur les altérations métaboliques, inflammatoires systémiques et tissulaires sont peu documentées. L’objectif de ce travail est de caractériser la perméabilité intestinale (i.e. jéjunum) et les mécanismes impliqués dans sa régulation dans l’obésité humaine sévère en conditions de jeûne (basal) et après un apport aigu de lipides selon des approches complémentaires in vivo (biomarqueurs), ex vivo (chambre de Ussing, étude des protéines de jonctions serrées en immunofluorescence) et in vitro (lignée cellulaire Caco-2/TC7). A l’état basal nous avons observé une diminution de la localisation de l’occludine et de la tricelluline dans les jonctions serrées au niveau du jéjunum et des taux circulants en zonuline et LPS binding protéine plus élevés chez les obèses. La perméabilité Jéjunale basale mesurée ex vivo en chambre de Ussing était comparable entre obèses et non obèses avec cependant des liens entre ces mesures et les paramètres de l’inflammation systémique chez les patients obèses (CRP et Haptoglobine). Une charge unique en lipides alimentaires, entrainait une augmentation rapide et significative de la perméabilité aux macromolécules (FITC-Dextran 4 kDa) in vitro et ex vivo, démontrant ainsi l’effet direct des lipides postprandiaux sur la barrière épithéliale. La perméabilité aux macromolécules après exposition aux lipides était plus élevée chez les patients obèses à fortiori diabétiques de type 2 et était associée à l’inflammation systémique (CRP) et intestinale (calprotectine fécale). Ainsi, nos résultats mettent en évidence un défaut de la barrière intestinale dans l'obésité caractérisée par une hyperperméabilité jéjunale démasquée par les lipides alimentaires et associée à l’inflammation et aux troubles métaboliques. / Intestinal barrier damage is associated with low-grade inflammation and metabolic impairment in rodent models of obesity. Whether intestinal permeability is altered in human metabolic disorders remains poorly investigated. Using a large cohort of well-characterized obese subjects and a human enterocyte model, we examined intestinal permeability in the basal state and after a challenge by a lipid load. We showed a reduction of occludin and tricellulin at jejunal tight junctions and increased serum levels of zonulin and LPS-Binding Protein in obese subjects. Jejunal permeability, directly measured in Ussing chambers in the fasting condition, was not significantly increased compared to non-obese subjects. Nevertheless, within the obese cohort, high permeability was associated with systemic inflammation (CRP and haptoglobin). A single lipid load increased permeability both in Caco-2/TC7 cells and ex vivo in human jejunum, demonstrating dietary lipids’ direct effects on the epithelial barrier. Permeability after the lipid load was significantly higher in the jejunum of obese subjects and associated with systemic and intestinal inflammation (CRP and fecal calprotectin) and type 2 diabetes. Thus, our results highlight an intestinal barrier defect in obesity, with a jejunal permeability increased by a lipid challenge and linked to inflammatory and metabolic impairments.

L’épithélium intestinal est un exemple de tissu qui a évolué pour former une barrière. Cette barrière limite le passage de produits toxiques d’agents pathogènes à partir de la lumière vers les tissus, tout en absorbant les nutriments, électrolytes et l'eau nécessaire à l'hôte. Les jonctions serrées sont des structures qui limitent le passage de la matière à travers l'espace intercellulaire. La capacité de mesurer le transport à travers cette barrière est d'une importance capitale car elle fournit des renseignements sur l’état de celle-ci, révélatrice de certains états pathologiques, puisque la perturbation ou dysfonctionnement des jonctions serrées est souvent due à ou est un indicatif de toxicité ou de maladie. En outre, le degré d'intégrité de la barrière est un indicateur clé de la pertinence d'un modèle in vitro particulier pour une utilisation en toxicologie et screening de médicaments. L'avènement de l'électronique organique a créé une occasion unique pour connecter les mondes de l'électronique et de la biologie, à l'aide des dispositifs tels que le transistor électrochimique organique (OECT), qui fournisse un moyen très sensible pour détecter des courants ioniques. Ces dispositifs ont une sensibilité sans précédent, dans un format qui peut être produit en masse à faible coût.Le but de cette étude était d'intégrer une couche de cellules représentative de la barrière gastro intestinale avec des OECTs, pour créer des dispositifs qui permettent de détecter les perturbations de cette barrière d’une manière rapide et sensible. Cette technique a était démontrée pour être au minimum aussi sensible mais d’une rapidité supérieure que les techniques actuelles sur le marché. / In biological systems, different tissues have evolved to form a barrier. An example is the intestinal epithelium, consisting of a single layer of cells lining the wall of the stomach and colon. It restricts the passage of harmful chemicals or pathogens from the light into the tissue, while selectively absorbing the most nutrients, electrolytes and water are necessary for the host. Tight junctions are structures which limit the passage of the material through the space between the cells. The ability to measure the paracellular and transcellular transport is of vital importance because it provides a wealth of information on the state of the barrier, indicative of certain disease states , since the disruption or malfunction of the structures involved in the transport through the tissue barrier is often caused or is indicative of toxicity or disease. In addition, the degree of integrity of the barrier is a key indicator of the relevance of a particular model in vitro for use in toxicology and drug screening. The advent of organic electronics has created a unique opportunity to connect the worlds of electronics and biology, using devices such as organic electrochemical transistor (OECT), which provides a very sensitive way to detect ionic currents. These devices have unprecedented sensitivity in a format that can be mass produced at low cost.The purpose of this study was to integrate a monolayer of cells representative of the gastro intestinal barrier with OECTs , to create devices that detect disruptions of the barrier in a timely and sensitive manner. This technique was demonstrated to be at least as sensitive, but a higher speed than current techniques on the market

INTRODUÇÃO: O carcinoma escamoso (CEC) de vulva é um tumor ginecológico de baixa frequência, cuja incidência aumenta com o passar dos anos. Entre as vias patogenéticas, destaca-se a neoplasia intraepitelial vulvar (NIV) diferenciada, que está relacionada com o líquen escleroso (LE). A maioria dos estudos publicados comparou o CEC vulvar com LE no âmbito morfológico apenas. Poucos avaliaram estas afecções em relação à biologia molecular, e nenhum avaliou o papel da junção intercelular (TJ). Nosso objetivo foi analisar a expressão de claudinas (proteínas atuantes na TJ) e do p53 nestas doenças. CASUÍSTICA E MÉTODOS: avaliamos o produto do oncogene TP53 e a expressão das claudinas 1, 2, 3, 4, 5, 7 e 11 em amostras de tecido vulvar humano de três grupos de pacientes: LE, CEC isolado (ICEC) e grupo controle. RESULTADOS: As claudinas 1, 2, 3 e 4 foram expressas igualmente nos três grupos. As claudinas 5, 7 e 11 não foram expressas nos grupos LE e ICEC, estando presentes apenas no grupo controle. Esta diferença foi significativa apenas para as claudinas 7 (p=0,013) e 11 (p=0,001). A proteína p53 foi mais expressa no grupo ICEC, seguida pelo LE e pelo grupo controle (p=0,017). CONCLUSÕES: As claudinas 5, 7 e 11 não se expressaram nos casos de LE e/ou ICEC. As claudinas 7 e 11 foram expressas apenas no grupo controle. Houve perda da expressão das claudinas 7 e 11 nos grupos com doença (LE e ICEC), em comparação ao grupo controle. Não houve diferença na expressão de claudinas entre os grupos LE e ICEC. Observou-se presença de p53 nos grupos estudados, cuja distribuição variou conforme o grupo analisado. Esta expressão foi maior no grupo ICEC, seguido pelo LE e, menor, no grupo controle / AIMS: Vulvar squamous cell carcinoma (SCC) is a rare gynaecologic cancer. Vulvar SCC has been shown to develop from vulvar intraepithelial neoplasias (VINs), which are related to lichen sclerosus (LS). Most studies to date have compared vulvar SCC to LS only morphologically, but no detailed molecular analysis has been performed. Our objective was to compare claudin and p53 expression in these diseases and determine if there was an association with expression and vulvar SCC progression. METHODS: Immunohistochemical analysis was performed in order to determine expression of p53 and claudin 1, 2, 3, 4, 5, 7, and 11 in human vulvar tissue samples from LS, SCC, and control patients. RESULTS: Claudin 1, 2, 3, 4, and 5 were expressed comparably in the three groups. Claudin 7 and 11 expression was significantly decreased in LS and SCC samples (p=0,013 and 0,001, respectively) compared with the control group. Expression of p53 was significantly increased in SCC and LS patient samples compared with the control group (p=0,017). CONCLUSIONS: Claudins 7 and 11 were expressed only in control group. There was loss of expression of claudins 7 and 11 in the disease groups (LS and/or SCC), comparing to control group. However, there was no significant difference in expression of any of the claudins between the LS and SCC samples. Furthermore, p53 expression is higher in SCC patients and lower in control group. However, expression of p53 did not vary between samples from isolated LS (ILS) and LS associated with SCC (ALSSCC) patients

INTRODUÇÃO: O carcinoma escamoso (CEC) de vulva é um tumor ginecológico de baixa frequência, cuja incidência aumenta com o passar dos anos. Entre as vias patogenéticas, destaca-se a neoplasia intraepitelial vulvar (NIV) diferenciada, que está relacionada com o líquen escleroso (LE). A maioria dos estudos publicados comparou o CEC vulvar com LE no âmbito morfológico apenas. Poucos avaliaram estas afecções em relação à biologia molecular, e nenhum avaliou o papel da junção intercelular (TJ). Nosso objetivo foi analisar a expressão de claudinas (proteínas atuantes na TJ) e do p53 nestas doenças. CASUÍSTICA E MÉTODOS: avaliamos o produto do oncogene TP53 e a expressão das claudinas 1, 2, 3, 4, 5, 7 e 11 em amostras de tecido vulvar humano de três grupos de pacientes: LE, CEC isolado (ICEC) e grupo controle. RESULTADOS: As claudinas 1, 2, 3 e 4 foram expressas igualmente nos três grupos. As claudinas 5, 7 e 11 não foram expressas nos grupos LE e ICEC, estando presentes apenas no grupo controle. Esta diferença foi significativa apenas para as claudinas 7 (p=0,013) e 11 (p=0,001). A proteína p53 foi mais expressa no grupo ICEC, seguida pelo LE e pelo grupo controle (p=0,017). CONCLUSÕES: As claudinas 5, 7 e 11 não se expressaram nos casos de LE e/ou ICEC. As claudinas 7 e 11 foram expressas apenas no grupo controle. Houve perda da expressão das claudinas 7 e 11 nos grupos com doença (LE e ICEC), em comparação ao grupo controle. Não houve diferença na expressão de claudinas entre os grupos LE e ICEC. Observou-se presença de p53 nos grupos estudados, cuja distribuição variou conforme o grupo analisado. Esta expressão foi maior no grupo ICEC, seguido pelo LE e, menor, no grupo controle / AIMS: Vulvar squamous cell carcinoma (SCC) is a rare gynaecologic cancer. Vulvar SCC has been shown to develop from vulvar intraepithelial neoplasias (VINs), which are related to lichen sclerosus (LS). Most studies to date have compared vulvar SCC to LS only morphologically, but no detailed molecular analysis has been performed. Our objective was to compare claudin and p53 expression in these diseases and determine if there was an association with expression and vulvar SCC progression. METHODS: Immunohistochemical analysis was performed in order to determine expression of p53 and claudin 1, 2, 3, 4, 5, 7, and 11 in human vulvar tissue samples from LS, SCC, and control patients. RESULTS: Claudin 1, 2, 3, 4, and 5 were expressed comparably in the three groups. Claudin 7 and 11 expression was significantly decreased in LS and SCC samples (p=0,013 and 0,001, respectively) compared with the control group. Expression of p53 was significantly increased in SCC and LS patient samples compared with the control group (p=0,017). CONCLUSIONS: Claudins 7 and 11 were expressed only in control group. There was loss of expression of claudins 7 and 11 in the disease groups (LS and/or SCC), comparing to control group. However, there was no significant difference in expression of any of the claudins between the LS and SCC samples. Furthermore, p53 expression is higher in SCC patients and lower in control group. However, expression of p53 did not vary between samples from isolated LS (ILS) and LS associated with SCC (ALSSCC) patients

In biological systems, different tissues have evolved to form a barrier. An example is the intestinal epithelium, consisting of a single layer of cells lining the wall of the stomach and colon. It restricts the passage of harmful chemicals or pathogens from the light into the tissue, while selectively absorbing the most nutrients, electrolytes and water are necessary for the host. Tight junctions are structures which limit the passage of the material through the space between the cells. The ability to measure the paracellular and transcellular transport is of vital importance because it provides a wealth of information on the state of the barrier, indicative of certain disease states , since the disruption or malfunction of the structures involved in the transport through the tissue barrier is often caused or is indicative of toxicity or disease. In addition, the degree of integrity of the barrier is a key indicator of the relevance of a particular model in vitro for use in toxicology and drug screening. The advent of organic electronics has created a unique opportunity to connect the worlds of electronics and biology, using devices such as organic electrochemical transistor (OECT), which provides a very sensitive way to detect ionic currents. These devices have unprecedented sensitivity in a format that can be mass produced at low cost.The purpose of this study was to integrate a monolayer of cells representative of the gastro intestinal barrier with OECTs , to create devices that detect disruptions of the barrier in a timely and sensitive manner. This technique was demonstrated to be at least as sensitive, but a higher speed than current techniques on the market

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 164-183.

Trinta e oito vacas leiteiras, 19 da raça Holandês e 19 da raça Girolando (½ e ¾), foram submetidas à elevadas temperaturas por restrição à sombra durante o período entre a ordenha da manhã e da tarde. Mensurações de temperatura retal, frequências respiratória e cardíaca e escore de ofegação, além de coletas de sangue, foram realizadas nos períodos pré ordenha. Produção de leite e características físico-químicas do mesmo foram acessadas. Durante os períodos de coleta se avaliou características ambientais com vistas a calcular um índice de temperatura e umidade (ITU). Primeiramente se buscou estabelecer diferenças em parâmetros fisiológicos, de leite e sangue de vacas com diferentes porcentagens de alelos oriundos da raça Holandesa no genoma (100, 75 e 50%) em função de aumentos no ITU. Animais puros Holandês apresentaram características que condizem com menor tolerância ao calor do que animais Girolando. Em um segundo momento se analisou o efeito do estresse térmico sobre a permeabilidade das junções firmes das células epiteliais da glândula mamária de vacas Holandês. Além disso, buscou-se perceber alterações na estabilidade do leite ao teste do álcool decorrentes de um possível aumento na permeabilidade de tais estruturas celulares. O parâmetro utilizado para aferir tal efeito foi o nível sanguíneo de lactose no plasma. Alterações lácteas foram percebidas em função de aumentos de ITU e se devem principalmente à reduções em produção de leite. Aumento nos parâmetros fisiológicos não influenciou a estabilidade do leite. Leite instável apresentou maior teor de lactose. Maior número de dias em lactação pode ser o responsável pela redução na estabilidade do leite. Percebeu-se relação inversamente proporcional entre permeabilidade das junções firmes e estabilidade do leite, porém o estado de estresse térmico, ao contrário do esperado, não apresentou influência nas células da glândula mamária. / Thirty-eight dairy cows, 19 Holstein and 19 Girolando (½ e ¾), were submitted to elevated temperatures due to shade deprivation between morning and evening milkings. Rectal temperature, heart and respiratory rates and panting score measurements, besides blood samples collection, were performed before each milking. Milk production and its physical-chemical characteristics were studied. Climatic variables were measured during data collection to calculate a temperature-humidity index (THI). Firstly, the study evaluated changes in physiological, blood and milk parameters according to the percentage of alleles derived from the Holstein breed (100, 75 and 50%) due to increases in THI. Pure Holstein cows presented characteristics that indicate lower heat tolerance than Girolando cows. Secondly, heat stress effects on mammary gland cells tight junctions permeability were evaluated in Holstein cows. Alterations in milk stability due to changes in permeability were also assessed. Plasma lactose was the parameter used to detect changes in tight junctions permeability. Modifications in milk characteristics were probably due to reduction in milk production. Increase in physiological parameters did not affect milk stability. Unstable milk samples presented higher lactose levels. Higher days in milk might be the main responsible for reductions in milk stability. There was an inversely proportional relation between tight junctions permeability and milk stability to the ethanol test, although heat stress, contradicting the expected, did not influenced mammary gland cells.

Trinta e oito vacas leiteiras, 19 da raça Holandês e 19 da raça Girolando (½ e ¾), foram submetidas à elevadas temperaturas por restrição à sombra durante o período entre a ordenha da manhã e da tarde. Mensurações de temperatura retal, frequências respiratória e cardíaca e escore de ofegação, além de coletas de sangue, foram realizadas nos períodos pré ordenha. Produção de leite e características físico-químicas do mesmo foram acessadas. Durante os períodos de coleta se avaliou características ambientais com vistas a calcular um índice de temperatura e umidade (ITU). Primeiramente se buscou estabelecer diferenças em parâmetros fisiológicos, de leite e sangue de vacas com diferentes porcentagens de alelos oriundos da raça Holandesa no genoma (100, 75 e 50%) em função de aumentos no ITU. Animais puros Holandês apresentaram características que condizem com menor tolerância ao calor do que animais Girolando. Em um segundo momento se analisou o efeito do estresse térmico sobre a permeabilidade das junções firmes das células epiteliais da glândula mamária de vacas Holandês. Além disso, buscou-se perceber alterações na estabilidade do leite ao teste do álcool decorrentes de um possível aumento na permeabilidade de tais estruturas celulares. O parâmetro utilizado para aferir tal efeito foi o nível sanguíneo de lactose no plasma. Alterações lácteas foram percebidas em função de aumentos de ITU e se devem principalmente à reduções em produção de leite. Aumento nos parâmetros fisiológicos não influenciou a estabilidade do leite. Leite instável apresentou maior teor de lactose. Maior número de dias em lactação pode ser o responsável pela redução na estabilidade do leite. Percebeu-se relação inversamente proporcional entre permeabilidade das junções firmes e estabilidade do leite, porém o estado de estresse térmico, ao contrário do esperado, não apresentou influência nas células da glândula mamária. / Thirty-eight dairy cows, 19 Holstein and 19 Girolando (½ e ¾), were submitted to elevated temperatures due to shade deprivation between morning and evening milkings. Rectal temperature, heart and respiratory rates and panting score measurements, besides blood samples collection, were performed before each milking. Milk production and its physical-chemical characteristics were studied. Climatic variables were measured during data collection to calculate a temperature-humidity index (THI). Firstly, the study evaluated changes in physiological, blood and milk parameters according to the percentage of alleles derived from the Holstein breed (100, 75 and 50%) due to increases in THI. Pure Holstein cows presented characteristics that indicate lower heat tolerance than Girolando cows. Secondly, heat stress effects on mammary gland cells tight junctions permeability were evaluated in Holstein cows. Alterations in milk stability due to changes in permeability were also assessed. Plasma lactose was the parameter used to detect changes in tight junctions permeability. Modifications in milk characteristics were probably due to reduction in milk production. Increase in physiological parameters did not affect milk stability. Unstable milk samples presented higher lactose levels. Higher days in milk might be the main responsible for reductions in milk stability. There was an inversely proportional relation between tight junctions permeability and milk stability to the ethanol test, although heat stress, contradicting the expected, did not influenced mammary gland cells.