Au cours de cette thèse, nous nous sommes intéressés à l’implication de la kallicréine-12 (KLK12), une protéase à sérine, dans la cancérogenèse pulmonaire. La KLK12 est connue comme étant surexprimée dans les tumeurs pulmonaires non à petites cellules mais son rôle dans la cancérogenèse n’est pas clairement établi. Nos travaux ont permis de lui attribuer un effet proangiogénique vis-à-vis des cellules endothéliales pulmonaires. En effet, la KLK12 peut stimuler la migration des cellules endothéliales pulmonaires en modifiant l’architecture de la matrice extracellulaire. D’autre part, elle est impliquée dans la régulation de la biodisponibilité de facteurs de croissance associés à l’angiogenèse tels que le Platelet-derived growth factor-B. De plus, nos travaux ont permis d’identifier une possible régulation de l’expression de la KLK12 par l’hypoxie, ce qui expliquerait sa surexpression dans les tumeurs pulmonaires et conforterait son implication dans l’angiogenèse. La confirmation in vivo des mécanismes d’action de la KLK12 pourrait permettre d’envisager son utilisation comme cible thérapeutique afin de réguler la néoangiogenèse tumorale. / In this thesis, we studied the involvement of the serine protease kallikrein-12 (KLK12), in lung carcinogenesis. The KLK12 is known to be overexpressed in non-small cell lung cancer but its role in carcinogenesis is not clearly established. Our work shows that it possesses a proangiogenic effect on pulmonary endothelial cells. Indeed, KLK12 stimulates lung endothelial cells migration notably by modulating the extracellular matrix architecture. On the other hand, KLK12 regulates the bioavailability of growth factors associated with angiogenesis such as plateletderived growth factor-B. In addition, our work has identified a possible regulation of the expression of KLK12 by hypoxia, which would explain its overexpression in lung tumors and would reinforce its involvement in angiogenesis. The confirmation in vivo of these mechanisms could help consider KLK12 as a therapeutic target for regulating tumor angiogenesis.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Angiogenesis is the development of new blood vessels from pre-existing capillaries, being an essential step in tumor growth for supplying nutrition and oxygen to cells in proliferation. A cell that may be involved in this process is the mast cell (MC), since besides the defense function, acts in the blood vessels regulation. The MC participation in the induction of angiogenesis has been suggested in various malignant tumors. The purposes of this study was to evaluate angiogenesis and mast cell density in oral epithelial dysplasia and squamous cell carcinoma (SCC). This is an observational, retrospective and quantitative study using the sample selection from the archives of the Department of Legal Medicine and Pathology and Laboratory of Oral Pathology, both from the Federal University of CearÃ. For MC evaluation , the sample was consisted of 73 paraffin blocks, distributed between SCC (n=30), epithelial dysplasia (n=23) and hyperplasias fibroepithelial (HFE) (n = 20), as control, and for angiogenesis the sample was 65 blocks, consisted of 24 SCC, 19 epithelial dysplasias and 22 HFE. Immunohistochemistry was performed using the MC-tryptase, CD31 and CD34 antibodies. For quantification, digital images were captured and then counting was performed using Image J software. The antibody staining percentage was determined using SAMM software. With regard to mast cells, there was a lower density in malignant lesions in relation to HFE and dysplasia (p = 0.0092). Evaluating angiogenesis, CD31 expression showed differences between epithelial dysplasia and SCC and between SCC and HFE, with a greater percentage of vessels in SCC (p <0.0001). However, CD34 expression did not differ between groups. The CD31 antibody was shown to be a better angiogenesis marker in oral mucosa than CD34. Increased vascularity in oral squamous cell carcinoma suggests that angiogenesis is necessary for tumor growth, increasing when the malignant transformation starts. However, no correlation was found between mast cells and angiogenesis. / AngiogÃnese à o surgimento de um novo vaso sanguÃneo a partir de capilares prÃ-existentes, sendo um passo essencial no crescimento tumoral por fornecer nutriÃÃo e oxigÃnio Ãs cÃlulas em proliferaÃÃo. Uma cÃlula que pode estar envolvida nesse processo à o mastÃcito, pois, alÃm da funÃÃo de defesa, atua na regulaÃÃo de vasos sanguÃneos. Sua participaÃÃo na induÃÃo da angiogÃnese tem sido sugerida em vÃrios tumores malignos. Os objetivos deste trabalho foram avaliar a angiogÃnese e a densidade de mastÃcitos em displasias epiteliais e no carcinoma espinocelular (CEC) de boca. Trata-se de um estudo observacional, retrospectivo e quantitativo, realizado atravÃs da seleÃÃo de amostra proveniente dos arquivos do Departamento de Patologia e Medicina Legal e do laboratÃrio de Patologia Bucal do curso de Odontologia, ambos da Universidade Federal do CearÃ. Para a avaliaÃÃo dos mastÃcitos, a amostra foi constituÃda por 73 blocos parafinados, distribuÃdos entre CEC (n=30), displasias epiteliais (n=23) e hiperplasias fibroepiteliais (HFE) (n=20), como controle, e para a angiogÃnese a amostra foi de 65 blocos, sendo 24 de CEC, 19 de displasias epiteliais e 22 de HFE. Foi realizada imunohistoquÃmica utilizando-se os anticorpos anti-triptase, para mastÃcitos e anti-CD31 e anti-CD34, para vasos sanguÃneos. Para quantificaÃÃo, foram capturadas imagens digitais e, em seguida, utilizados softwares para auxiliar na contagem dos mastÃcitos (Image J) e para determinaÃÃo do percentual de marcaÃÃo do anticorpo (SAMM). Com relaÃÃo aos mastÃcitos, houve menor densidade destes nas lesÃes malignas em relaÃÃo Ãs HFE e displasias (p=0,0092). Avaliando angiogÃnese, a expressÃo de CD31 mostrou diferenÃa entre os grupos CEC e displasia epitelial e entre CEC e HFE, havendo um maior percentual de vasos nos CEC (p<0,0001). Contudo, o CD34, nÃo mostrou diferenÃa entre os grupos. O anticorpo CD31 mostrou-se melhor marcador de angiogÃnese em mucosa oral do que CD34. O aumento da vascularizaÃÃo em CEC oral sugere que a angiogÃnese à necessÃria ao crescimento tumoral, aumentando à medida que inicia o processo de malignizaÃÃo. NÃo foi encontrada correlaÃÃo entre mastÃcitos e angiogÃnese.

As proteínas S100A8/A9 são expressas em diferentes tipos celulares e quando sozinhas ou complexadas e em baixas concentrações, promoveram proliferação, migração celular e formação de estruturas capilares. Por outro lado, quando em altas concentrações, esse complexo inibe o crescimento de diversos tipos de células tumorais murinas e humanas. Ainda, tanto a proteína S100A9 humana, quanto um peptídeo sintético idêntico a porção C-terminal da proteína S100A9 murina (pS100A9m) possuem efeitos antinociceptivo e imunorregulatório. Apesar dessas evidencias, até o momento não foi investigado o efeito do pS100A9m sobre a angiogênese e a tumorigênese. Portanto, o objetivo do presente estudo foi investigar, in vitro, o efeito do pS100A9m sobre os eventos fundamentais envolvidos com a angiogênese e o desenvolvimento tumoral. Para tanto, a fim de avaliar o efeito do pS100A9m sobre a angiogênese foi utilizada a linhagem de células endoteliais tímicas murinas (tEnd.1) nos ensaios de proliferação, migração da célula endotelial em meio de cultura, avaliada nos modelos de wound healing e transwell ou migração em meio condicionado, obtido de células tumorais LLC WRC256, avaliada no modelo de transwell, ensaio de adesão (aos componentes de matriz, tais como o colágeno tipo I, fibronectina e laminina) e formação de tubos em matrigel tridimensional (3D). Para os estudos sobre o efeito do pS100A9m sobre as células tumorais, foi utilizada a linhagem de células LLC WRC256 para realização dos ensaios funcionais de proliferação, migração (wound healing) e adesão (sobre os componentes da matriz extracelular). Os resultados obtidos demonstraram que o pS100A9m inibe a proliferação, migração, adesão sobre os componentes de matriz e, consequentemente, a formação de estruturas capilares em matriz 3D. Em relação às células tumorais LLC WRC256, foi observada, novamente, a ação inibitória do pS100A9m sobre os eventos de proliferação e migração. Em relação à adesão, o peptídeo aumentou a capacidade de adesão das células tumorais sobre o colágeno tipo I e fibronectina, porém inibiu a adesão dessas células sobre laminina. Em conclusão, os dados aqui obtidos demonstram que o pS100A9m inibe in vitro os eventos fundamentais envolvidos com a angiogênese e com a progressão tumoral. Desta forma, o peptídeo da porção C-terminal da proteína S100A9 pode ser considerado uma nova ferramenta para o estudo da angiogênese e tumorigênese, além apresentar potencial para uma possível aplicação terapêutica nesses processos / The S100A8/A9 proteins are expressed in different cell types and alone or when complexed, and at low concentrations promoted proliferation, cell migration and formation of capillary structures. On the other hand, at higher concentrations, this compound inhibits the growth of many types of murine and human tumor cells. Moreover, both human S100A9 protein and a synthetic peptide identical to the C-terminal portion of murine S100A9 (mS100A9p) present antinociceptive and immunomodulatory effects. Despite these evidences, the effect of mS100A9p on angiogenesis and tumorigenesis has not been investigated. Therefore, the aim of this study was to investigate the in vitro effect of mS100A9p on crucial events involved in angiogenesis and tumor development. For this, in order to evaluate the effect of mS100A9p on angiogenesis was used the murine endothelial cell line derived from thymus hemangioma (tEnd.1) for proliferation assays, endothelial cell migration in the presence of culture medium (scratch wound healing and chemotaxis assays) or in conditioned medium prevenient from LLC WRC256 tumor cells (chemotaxis assays), adhesion assay (on extracellular matrix components, such as type I collagen, fibronectin and laminin) and tube like-structure formation in 3D matrix. For the analyzes of the effect of mS100A9p on tumor cells, the cell line LLC WRC256 was used to perform functional assays such as proliferation, migration (scratch wound healing model) and adhesion (on components of the extracellular matrix). The results showed that the mS100A9p inhibits the proliferation, migration and adhesion of endothelial cells to the matrix components and consequently the formation of capillary structures in 3D matrix. Regarding LLC WRC256 tumor cells, it was observed again the inhibitory action of the mS100A9p on proliferation and migration events. In relation to cellular adhesion, this peptide increased this parameter of tumor cells on type I collagen and fibronectin. However mS100A9p inhibited the adhesion of these cells on laminin. In conclusion, the data obtained show that the mS100A9p inhibits in vitro crucial events involved in angiogenesis and tumor progression. Thus, the C-terminal portion of murine S100A9 protein may be considered as a new tool for the study of tumorigenesis and angiogenesis besides presenting potential to a possible therapeutic application in these processes

As junções GAP são canais intercelulares responsáveis pela comunicação de células vizinhas, por onde passam pequenas moléculas e íons que mantêm a homeostasia celular. A junção GAP é formada seis proteínas, as conexinas. Na célula endotelial encontram-se as conexinas 37, 40 e 43. Nesse estudo, estimulamos a angiogênese em córnea de camundongos, através da cauterização com cristal de nitrato de prata. Foram utilizados camundongos heterozigotos para o gene da conexina 43 (Cx43+/-) e camundongos selvagens (Cx43+/+). As córneas foram analisadas 2 e 6 dias após a cauterização atravéspor meio da morfologia vascular, detecção das Cx37, Cx40, Cx43, PCNA por meio de Western Blot e avaliação ultraestrutural das células endoteliais. Como resultado obtivemos uma menor área de preenchimento vascular nos animais Cx43+/- em 2 e 6 dias após a lesão corneal, porém, em relação a extensão dos vasos não foi observado diferenças entre os grupos. Uma menor proliferação celular foi verificada através da detecção do PCNA, nos animais heterozigotos, somente após 2 dias da lesão corneal. Não houve alteração da Cx37 e Cx40 entres os grupos. A Cx43 parece ser uma conexina importante para a célula endotelial durante o processo de angiogênese. / The GAP junctions are intercellular streams responsible for the communication between close cells, which allow small molecules and ions to pass through them maintaining the cellular homeostasis. The GAP junction is formed of six proteins, the connexin. In the endothelial cell, there are the connexin 37, 40 and 43. In this study, we stimulated the angiogenesis in the mice\'s cornea through its cauterization using silver\'s crystal glass. It was used heterozygote mice to the gene of connexin 43 (Cx43+/-) and wild mice (Cx43+/+). The corneas were analyzed 2 and 6 days after the cauterization through the vascular morphology, detection of Cx37, Cx40, Cx43, PCNA through Western Blot and ultrastructural evaluation of the endothelial cells. As a result, we obtained a smaller area of vascular fillness in the animals Cx43+/- with 2 and 6 days of corneal injury, however, in regard to the extensions of the vessels, it wasn\'t observed any changes between the groups. A smaller proliferation of cells was verified, through the detection of PCNA, in the heterozygote animals only 2 days after the corneal injury. There wasn\'t any modification of the Cx37 and Cx40 between groups. The Cx43 seems to be an important connexin to the endothelial cell during the process of angiogenesis.

Stroke is a leading cause of death and disability worldwide. Although rapid recognition and prompt treatment have dropped mortality rates, most stroke survivors are left with permanent disability. Approximately 87% of all strokes result from the thromboembolic occlusion of the cerebrovasculature (ischemic strokes). Potential stroke therapeutics have included anti-inflammatory drugs, as well as many other targets with the goal of mitigating the acute and chronic inflammatory responses typically seen in an ischemic stroke. While these approaches have had great success in preclinical studies, their clinical translation has been less successful. Master inflammatory cytokines, such as IL-1, are of particular interest. IL-1’s isoforms, IL-1α and IL-1β, were long thought to have similar function. While IL-1β has been extensively studied in stroke, the role of IL-1α during post stroke inflammation has been overlooked. Because IL-1 inhibitors have been unsuccessful in clinical application, we reasoned that IL-1α may provide previously unknown benefits to the brain after injury. We hypothesized that IL-1α could be protective or even accelerate reparative processes in the brain such as producing new blood vessels (angiogenesis) or neurons (neurogenesis). To test that IL-1α is protective after stroke, we tested IL-1α’s protective effects on primary cortical neurons in in vitro models of stroke. We showed that IL-1α was directly protective on primary cortical neurons in a dose-dependent fashion. We then performed mouse middle cerebral artery occlusion stroke studies to determine the safety of giving IL-1α in vivo. These studies showed that administering IL-1α acutely was neuroprotective. However, intravenous (IV) administration of IL-1α resulted in transient, hemodynamic changes following drug delivery. To minimize these systemic effects, we administered IL-1α intra-arterially (IA) directly into the stroke affected brain tissue, allowing us to significantly lower the concentration of administered IL-1α. In comparison to IV, IA IL-1α showed greater histological protection from ischemic injury as well as improved functional recovery following stroke, all without systemic side effects. To test that IL-1α could aid in neurorepair following stroke, we tested IL-1α’s ability to help damaged blood vessels repair in vitro. We found that IL-1α significantly increased brain endothelial cell activation, proliferation, migration, and capillary formation. We tested IL-1α’s proangiogenic properties in vivo by administering IL-1α three days following stroke. Delayed administration allowed us to separate IL-1α’s acute neuroprotective effects from potential subacute angiogenic effects. We found that mice receiving IL-1α performed significantly better on behavioral tests and also showed greater vascularization within the penumbra two weeks following stroke. We also found that IL-1α treated animals showed more endothelial activation than vehicle treated animals. Finally, our studies showed that IL-1α treated animals showed increased early-phase neurogenesis with evidence of increased proliferation at the subventricular zone suggesting that IL-1α’s beneficial effects are even more far-reaching than previously thought. In conclusion, our experiments suggest that the inflammatory cytokine IL-1α is neuroprotective and neuroreparative in experimental ischemic stroke and worthy of further study as a novel stroke therapy.

The blood and lymphatic vascular systems coordinate to play critical roles in tissue fluid homeostasis and immune function and are fundamentally associated with diseases including inflammation, wound healing, edema, and tumor progression and metastasis. Their coordination during vascular growth and remodeling represents an under-investigated area of research in which a better understanding will provide insights into future therapeutic approaches. Angiogenesis and lymphangiogenesis are the growth of new blood or lymphatic vessels, respectively, from pre-existing vessels. The comprehensive goal of this work was to provide a new perspective on the relationships between angiogenesis and lymphangiogenesis in microvascular networks and develop tools needed to probe the mechanisms involved in lymphatic/blood vessel patterning and identity. The first aim of this study was to characterize the spatiotemporal relationships between lymphatic and blood vessel growth in response to an inflammatory stimulus. We found that lymphangiogenesis temporally lagged angiogenesis during inflammation and that the presence of lymphatic vessels attenuated angiogenesis. We also identified increased lymphatic/blood endothelial cells connections and a novel lymphatic marker. These results motivated the need for a system to probe the multicellular and multisystem interactions suggested by these findings. Our lab recently developed the rat mesentery culture model as an ex vivo model for investigating angiogenesis in the context of intact microvascular networks. The second aim was to determine whether this model can be used to study lymphangiogenesis. We found that vascular endothelial growth factor C stimulated lymphatic sprout formation in the rat mesentery culture model and confirmed the ability to observe angiogenesis and lymphangiogenesis simultaneously in an ex vivo environment. This suggests the rat mesentery culture model can be used to investigate the dynamics of lymphatic/blood vessel patterning and plasticity motivated by our in vivo work. The final aim of this work was to investigate the ability to induce phenotypic plasticity in intact vasculature by using lysophosphatidic acid, an agonist suggested to cause blood-to-lymphatic endothelial cell transition. We demonstrated that while lysophosphatidic acid stimulated angiogenesis, it was not sufficient to reprogram blood vessels to acquire a lymphatic phenotype. These results underscore the necessity of investigating these multisystem relationships in the context of intact microvascular networks. These studies as a whole demonstrate the coordination that exists between blood and lymphatic vessels and reinforce the need for novel models that incorporate the complexities of the entire microvasculature. / acase@tulane.edu

Understanding angiogenesis increases comprehension of pathological conditions such as tumor growth and peripheral artery disease. Angiogenesis is the growth of new vessels from pre-existing vessels and commonly associated with two modes: capillary sprouting and capillary splitting. Past observations in our laboratory provide evidence of vascular islands in the adult microcirculation. Vascular islands are defined as endothelial cell segments disconnected from nearby networks. The two objectives of this specific aim were to (1) determine if vascular islands are involved in angiogenesis during microvascular network growth, and (2) determine whether vascular islands associated with microvascular regression are involved in microvascular remodeling. Mesenteric tissues were harvested from adult male Wistar rats according to the experimental groups: unstimulated, post stimulation (3, 10 and 70 days), and 70 days post stimulation + restimulation (3 and 10 days). Stimulation was induced by mast cell degranulation via intraperitoneal injections of compound 48/80. Tissues were immunolabeled for PECAM (endothelial cells), NG2 (pericytes), collagen IV (basement membrane), and BrdU (proliferation). On day 3, the percentage of islands with at least one BrdU-positive cell increased compared to the unstimulated level and was equal to the percentage of capillary sprouts with at least one BrdU-positive cell. At day 10, the number of vascular islands per vascular area dramatically decreased compared to unstimulated and day 3 levels. Data collected independently for both aims showed that percent vascular area per tissue area and length density increased by day 10 post stimulation compared to the unstimulated group. At day 70, vascular area and length density were then decreased, indicating vascular regression compared to the day 10 levels. During regression at day 70, the number of islands increased. The disconnected endothelial cells were commonly bridged to surrounding networks by collagen IV labeling. NG2-positive pericytes were observed both along the islands and the collagen IV tracks. At 3 days post restimulation, vascular islands contained BrdU-positive cells. By day 10 post restimulation, when vascular area and length density were again increased, and the number of vascular islands was dramatically reduced. The result of this study suggest that (i) segment proliferation correlates with sprouting and network remodeling, (ii) blood vessel segments could provide a novel mode of endothelial cell presence in angiogenesis, (iii) blood vessel segments may be a reserve to connect with existing vasculature, and (iv) vascular islands originating during microvascular regression are capable of undergoing proliferation and incorporation into nearby networks during network regrowth. / acase@tulane.edu

acase@tulane.edu

Solid cancer tumors must recruit new blood vessels for growth and maintenance. Discovering drugs that block this tumor-induced development of new blood vessels (angiogenesis) is an important approach in cancer treatment. However, the complexity of angiogenesis and the difficulty in implementing and evaluating medical changes prevent the discovery of novel and effective new therapies. This paper presents a massively parallel computational search-based approach for the discovery of novel potential cancer treatments, using a high fidelity simulation of angiogenesis. Discovering new therapies is viewed as multi-objective combinatorial optimization over two competing objectives: minimizing the medical cost of the intervention while minimizing the oxygen provided to the cancer tumor by angiogenesis. Results show the effectiveness of the search process in finding simple interventions that are currently in use and more interestingly, discovering some new approaches that are counterintuitive yet effective. Distributed systems are becoming more prevalent as the demand for connectivity increases. Developers are faced with the challenge of creating software systems that meet these demands and adhere to good software practices. Technologies of today aid developers in this, but they may cause applications to suffer performance problems and require developers to abandon basic software concepts, such as modularization, performance, and maintainability. This work presents the Vitruvian framework that provides solutions to common distribution goals, and distributes applications using replication and transparency at varying stages of application development.

Tumor angiogenesis, the ability of tumor cells to stimulate blood vessel growth, is one the most critical steps of tumor progression. To support the growth of the expanding tumor, the “angiogenic switch” is turned on, which is often triggered by hypoxia (i.e., low oxygen)-mediated events such as expression of vascular endothelial growth factor (VEGF), causing normally quiescent endothelial cells to proliferate and sprout. An emerging picture of angiogenesis suggests that while governed by complex mechanisms, cell adhesion molecules (CAMs) plays a pivotal role in the regulation of angiogenesis. Our laboratory recently identified multiple previously unknown proteins including, transmembrane and immunoglobulin domain containing 1 (TMIGD1) and immunoglobulin-containing and proline-rich receptor 1 (IGPR1). Immunoglobulin-containing and cysteine-rich receptor 1 (IGCR1) represents the third remember of IGPR-1 family proteins. To investigate the expression and function of IGCR1, we have developed a rabbit polyclonal anti-IGCR1 antibody and demonstrated that IGCR1 is expressed in the endothelial cells of human blood vessels. To examine possible function of IGCR1, we have generated porcine aortic endothelial (PAE) cells over-expressing IGCR1. We demonstrate that IGCR1 expression in PAE cells inhibited cell proliferation and capillary tube formation as measured by colorimetric MTT and matrigel tube formation assays, respectively. In contrast, over-expression of IGCR1 in PAE cells inhibited cell migration as measured by wounding assay. Taken together, this study identifies IGCR1 as a novel regulator of angiogenesis. Given, angiogenesis is a highly coordinated cellular processes controlled spatially and temporally by a myriad of cell surface receptors and ligands, IGCR1 by modulating the rate of endothelial cell proliferation and migration, plays a significant role in the formation of blood vessels. / 2018-07-11T00:00:00Z