As malformações craniofaciais (MCFs) compreendem uma vasta e heterogênea gama de doenças que envolvem o acometimento de tecidos do crânio e da face, sendo que indivíduos afetados enfrentam morbidade e deficiências funcionais relevantes. O entendimento da etiologia das MCFs é de extrema importância, pois poderá levar ao desenvolvimento ou melhoria de estratégias preventivas e terapêuticas. As MCFs são oriundas principalmente de distúrbios no desenvolvimento da crista neural cranial e seus derivados mesenquimais. Neste contexto, modelos baseados em células derivadas de crista neural são de grande potencial para o entendimento das MCFs, já que estudos funcionais podem ser realizados nestas células para averiguar fenótipos diretamente relacionados às doenças. Neste trabalho, nós empregamos esta estratégia na investigação de três tipos de MCFs: fissuras labiopalatinas não sindrômicas (FLP NS), síndrome de Richieri-Costa-Pereira (SRCP) e síndrome de Treacher Collins (STC). As FLP NS foram investigadas por meio de ensaios transcriptômicos e funcionais em células-tronco de polpa de dente decíduo, que são células mesenquimais adultas derivadas de crista neural cranial. Identificamos uma assinatura de expressão gênica específica às FLP NS, com desregulação de uma rede gênica responsável pelo reparo de quebras duplas no DNA, resultando no acúmulo deste tipo de lesão em células de indivíduos afetados pela doença. Estes achados revelam um novo mecanismo patogênico para as FLP NS e corroboram observações prévias que sugeriam sobreposição de etiologias entre esta doença e o câncer. A SRCP e a STC foram investigadas com o uso de uma nova metodologia para a geração de células de crista neural a partir de células-tronco pluripotentes induzidas (induced pluripotent stem cells; iPSCs) para recapitular o desenvolvimento craniofacial. Realizamos triagem de fenótipos celulares e identificamos desregulação de diferenciação osteogênica em células mesenquimais derivadas de crista neural de pacientes com SRCP, o que foi corroborado por ensaios de RNA de interferência. Além disso, mostramos que células mesenquimais de crista neural de pacientes com STC apresentam apoptose elevada aliada a alterações durante diferenciação osteogênica e condrogênica. Estes resultados revelam que células mesenquimais de crista neural estão alteradas na SRCP e STC, colaborando para o esclarecimento dos mecanismos patogênicos responsáveis por estas síndromes. Assim sendo, nós evidenciamos a aplicabilidade da modelagem de MCFs por meio de células oriundas da crista neural, e esses achados inéditos contribuirão para um melhor entendimento da etiologia das MCFs, e servem de base para futuras estratégias de pesquisa na área de doenças craniofaciais / Craniofacial malformations (CFMs) comprise a large and heterogeneous group of disorders in which tissues of the skull and face are affected. Affected subjects suffer from significant functional impairment and morbidity, and understanding the aetiology of these disorders is of great importance, as it may lead to the development or improvement of preventive and therapeutic strategies in the future. CFMs are largely considered to arise from developmental disturbances in the cranial neural crest and its cranioskeletal and cartilaginous mesenchymal derivatives. Neural crest-derived cell models have the potential to provide invaluable insight into the pathogenesis of CFMs, as functional studies can be to assess phenotypes in disease-relevant cell lineages. In this work, we applied this strategy to investigate three craniofacial disorders: non-syndromic cleft lip/palate (NSCL/P), Richieri-Costa-Pereira syndrome (RCPS), and Treacher Collins syndrome (TCS). NSCL/P was investigated through transcriptomic and functional assays on stem cells from human exfoliated deciduous teeth, which are neural crest-derived, adult mesenchymal cells. We identified a NSCL/P-specific dysregulated transcriptional signature involving a gene network responsible for DNA double-strand break repair that results in accumulation of DNA damage in patients\' cells. These findings revealed a novel pathogenetic mechanism for NSCL/P and support previous observations pointing towards an aetiological overlap between this disease and cancer. RCPS and TCS were investigated with the use of a novel approach to generate neural crest cells from patient-specific induced pluripotent stem cells (iPSCs) as a means to recapitulate craniofacial development. We demonstrated that RCPS and TCS somatic cells can be successfully used to generate iPSCs and iPSC-derived neural crest cells and their mesenchymal derivatives. Phenotype screening showed that RCPS neural crest-derived mesenchymal cells display dysregulation of osteogenic differentiation, which was supported by confirmatory knockdown assays. Further, we report elevated apoptosis in TCS neural crest-derived mesenchymal cells, which was allied to alterations in chondrogenic and osteogenic differentiation. These results will aid in clarifying the pathogenic mechanism determining RCPS and TCS, revealing that neural crest mesenchymal cells are altered in these syndromes. In conclusion, we attested the applicability of NC-derived cell types to provide clues regarding the pathogenetic mechanisms leading to CFMs, and these novel findings will aid in dissecting the aetiology of CFMs by providing grounds to direct future efforts in craniofacial research

As malformações craniofaciais (MCFs) compreendem uma vasta e heterogênea gama de doenças que envolvem o acometimento de tecidos do crânio e da face, sendo que indivíduos afetados enfrentam morbidade e deficiências funcionais relevantes. O entendimento da etiologia das MCFs é de extrema importância, pois poderá levar ao desenvolvimento ou melhoria de estratégias preventivas e terapêuticas. As MCFs são oriundas principalmente de distúrbios no desenvolvimento da crista neural cranial e seus derivados mesenquimais. Neste contexto, modelos baseados em células derivadas de crista neural são de grande potencial para o entendimento das MCFs, já que estudos funcionais podem ser realizados nestas células para averiguar fenótipos diretamente relacionados às doenças. Neste trabalho, nós empregamos esta estratégia na investigação de três tipos de MCFs: fissuras labiopalatinas não sindrômicas (FLP NS), síndrome de Richieri-Costa-Pereira (SRCP) e síndrome de Treacher Collins (STC). As FLP NS foram investigadas por meio de ensaios transcriptômicos e funcionais em células-tronco de polpa de dente decíduo, que são células mesenquimais adultas derivadas de crista neural cranial. Identificamos uma assinatura de expressão gênica específica às FLP NS, com desregulação de uma rede gênica responsável pelo reparo de quebras duplas no DNA, resultando no acúmulo deste tipo de lesão em células de indivíduos afetados pela doença. Estes achados revelam um novo mecanismo patogênico para as FLP NS e corroboram observações prévias que sugeriam sobreposição de etiologias entre esta doença e o câncer. A SRCP e a STC foram investigadas com o uso de uma nova metodologia para a geração de células de crista neural a partir de células-tronco pluripotentes induzidas (induced pluripotent stem cells; iPSCs) para recapitular o desenvolvimento craniofacial. Realizamos triagem de fenótipos celulares e identificamos desregulação de diferenciação osteogênica em células mesenquimais derivadas de crista neural de pacientes com SRCP, o que foi corroborado por ensaios de RNA de interferência. Além disso, mostramos que células mesenquimais de crista neural de pacientes com STC apresentam apoptose elevada aliada a alterações durante diferenciação osteogênica e condrogênica. Estes resultados revelam que células mesenquimais de crista neural estão alteradas na SRCP e STC, colaborando para o esclarecimento dos mecanismos patogênicos responsáveis por estas síndromes. Assim sendo, nós evidenciamos a aplicabilidade da modelagem de MCFs por meio de células oriundas da crista neural, e esses achados inéditos contribuirão para um melhor entendimento da etiologia das MCFs, e servem de base para futuras estratégias de pesquisa na área de doenças craniofaciais / Craniofacial malformations (CFMs) comprise a large and heterogeneous group of disorders in which tissues of the skull and face are affected. Affected subjects suffer from significant functional impairment and morbidity, and understanding the aetiology of these disorders is of great importance, as it may lead to the development or improvement of preventive and therapeutic strategies in the future. CFMs are largely considered to arise from developmental disturbances in the cranial neural crest and its cranioskeletal and cartilaginous mesenchymal derivatives. Neural crest-derived cell models have the potential to provide invaluable insight into the pathogenesis of CFMs, as functional studies can be to assess phenotypes in disease-relevant cell lineages. In this work, we applied this strategy to investigate three craniofacial disorders: non-syndromic cleft lip/palate (NSCL/P), Richieri-Costa-Pereira syndrome (RCPS), and Treacher Collins syndrome (TCS). NSCL/P was investigated through transcriptomic and functional assays on stem cells from human exfoliated deciduous teeth, which are neural crest-derived, adult mesenchymal cells. We identified a NSCL/P-specific dysregulated transcriptional signature involving a gene network responsible for DNA double-strand break repair that results in accumulation of DNA damage in patients\' cells. These findings revealed a novel pathogenetic mechanism for NSCL/P and support previous observations pointing towards an aetiological overlap between this disease and cancer. RCPS and TCS were investigated with the use of a novel approach to generate neural crest cells from patient-specific induced pluripotent stem cells (iPSCs) as a means to recapitulate craniofacial development. We demonstrated that RCPS and TCS somatic cells can be successfully used to generate iPSCs and iPSC-derived neural crest cells and their mesenchymal derivatives. Phenotype screening showed that RCPS neural crest-derived mesenchymal cells display dysregulation of osteogenic differentiation, which was supported by confirmatory knockdown assays. Further, we report elevated apoptosis in TCS neural crest-derived mesenchymal cells, which was allied to alterations in chondrogenic and osteogenic differentiation. These results will aid in clarifying the pathogenic mechanism determining RCPS and TCS, revealing that neural crest mesenchymal cells are altered in these syndromes. In conclusion, we attested the applicability of NC-derived cell types to provide clues regarding the pathogenetic mechanisms leading to CFMs, and these novel findings will aid in dissecting the aetiology of CFMs by providing grounds to direct future efforts in craniofacial research

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.