Doenças da córnea estão entre as principais causas de cegueira e os mecanismos de lesão e reparação estão em grande parte concentradas no epitélio, porém os mediadores e alvos para possíveis intervenções terapêuticas são pouco conhecidos.Nas agressões ao epitélio da córnea, a ativação dos receptores vanilóides de potencial transitório 1 (TRPV1) leva a resposta inflamatória e cicatricial. O objetivo desse trabalho é identificar os mecanismos de sinalização e resposta do TRPV1 na córnea de animais experimentais. O cultivo de células epiteliais de córnea de ratos, a identificação de mediadores por western blot, medida do influxo de cálcio, resposta de citocinas medidas por ensaio quantitativo de PCR em tempo real (RNAm) e ELISA (proteína) após estímulos nocioceptivos ou inflamatórios; e a investigação histológica e imunohistoquimica em modelos animais, sejam ratos com diabetes mellitus (DM) por 8 semanas ou expostos a cloreto de benzalcônio a 0,2% (BAC) por 7 dias. Camundongos TRPV1-/- comparados aos controles C57 foram comparados sem estimulo, ou sob estimulo único com CAP a 1µM, BAC 0,2 % por 7 dias ou após queimadura alcalina com NaOH a 1M. Os resultados mostraram a presença de TRPV1 em epitélio de córnea em cultura primária, mostraram que essas células respondem com influxo de cálcio ao estímulo com o agonista Capsaicina a 1µM e aumento de TNF? e IL-1? (sendo máximo nas combinações CAP+CPZ e Win+CAP, respectivamente). Em ratos com DM e BAC ocorre a redução da expressão do RNAm de IL-1? (p=0,0269) na córnea, entre outras alterações. Os camundongos TRPV1-/- tem fenótipo físico e ocular normal, porém reduzida sensibilidade a CAP 1µM. O tratamento com BAC leva a diminuição da secreção lacrimal (p=0,0011) e de IL-1? e TNF? na glândula lacrimal (GL) de TRPV1-/- machos (p=0,0177, p=0,0245, respectivamente). A queimadura alcalina com NaOH 1M resultou em melhor cicatrização e maior espessura epitelial no grupo TRPV1-/-. Em ix conclusão, o TRPV1 está presente na córnea e atua em resposta a agressões externas. Situações adquiridas como DM e toxicidade por BAC, reconhecidas como neuropáticas diminuem a expressão de mediadores inflamatórios. A ausência genética e TRPV1 não altera o fenótipo, mas apresenta menor sensibilidade e melhor restauração da superfície ocular após queimadura alcalina / Corneal diseases are among the leading causes of blindness.Damage and repair mechanisms are largely concentrated in the epithelium, but the mediators and targets for possible therapeutic interventions are poorly understood. The aggressions to the corneal epithelium, the activation of vanilloid receptors transient potential 1 (TRPV1) leads to inflammatory and wound healing. The aim of this study is to identify the signaling mechanisms and TRPV1 response in the cornea of experimental animals.The culture of epithelial cells from rat cornea, to identify mediators by western blot analysis, measurement of calcium influx, cytokine response measured by PCR real time (mRNA) and ELISA (protein) nocioceptivos or after inflammatory stimuli; and the histological and immunohistochemical investigation in animal models are mice with diabetes mellitus (DM) for 8 weeks, and exposed to benzalkonium chloride at 0.2% (BAC) for 7 days. Mice TRPV1-/- compared to control C57 were compared with no stimulus, or under single stimulation with 1 µM Capsaicine (CAP), BAC 0.2% for 7 days or after the alkali burn with NaOH 1 M.The results showed the presence of TRPV1 in corneal epithelium in primary culture, showed that these cells respond to calcium influx the stimulus with capsaicin agonist 1?M and increase of TNF? and IL-1? (being maximum at the CAP + CPZ combinations and Win + CAP, respectively). In rats with DM and BAC occurs reducing the expression of IL-1? mRNA (p = 0.0269) in the cornea, among other changes. The TRPV1-/- mice have physical phenotype and normal ocular but low sensitivity to CAP 1?M. Treatment with BAC leads to decreased tear secretion (p = 0.0011) and IL-1? and TNF? in the lacrimal gland (GL) of TRPV1-/- mice (p = 0.0177, p = 0.0245, respectively) . The alkaline burn with NaOH 1M resulted in better healing and greater epithelial thickness in TRPV1-/- group .In conclusion, TRPV1 is present in the cornea and operates in response to external aggressions. Situations existing as DM and xi toxicity BAC recognized as neuropathic decrease the expression of inflammatory mediators. Genetic absence and TRPV1 does not alter the phenotype, but has lower sensitivity and better restoration of the ocular surface after alkaline burn

Doenças da córnea estão entre as principais causas de cegueira e os mecanismos de lesão e reparação estão em grande parte concentradas no epitélio, porém os mediadores e alvos para possíveis intervenções terapêuticas são pouco conhecidos.Nas agressões ao epitélio da córnea, a ativação dos receptores vanilóides de potencial transitório 1 (TRPV1) leva a resposta inflamatória e cicatricial. O objetivo desse trabalho é identificar os mecanismos de sinalização e resposta do TRPV1 na córnea de animais experimentais. O cultivo de células epiteliais de córnea de ratos, a identificação de mediadores por western blot, medida do influxo de cálcio, resposta de citocinas medidas por ensaio quantitativo de PCR em tempo real (RNAm) e ELISA (proteína) após estímulos nocioceptivos ou inflamatórios; e a investigação histológica e imunohistoquimica em modelos animais, sejam ratos com diabetes mellitus (DM) por 8 semanas ou expostos a cloreto de benzalcônio a 0,2% (BAC) por 7 dias. Camundongos TRPV1-/- comparados aos controles C57 foram comparados sem estimulo, ou sob estimulo único com CAP a 1µM, BAC 0,2 % por 7 dias ou após queimadura alcalina com NaOH a 1M. Os resultados mostraram a presença de TRPV1 em epitélio de córnea em cultura primária, mostraram que essas células respondem com influxo de cálcio ao estímulo com o agonista Capsaicina a 1µM e aumento de TNF? e IL-1? (sendo máximo nas combinações CAP+CPZ e Win+CAP, respectivamente). Em ratos com DM e BAC ocorre a redução da expressão do RNAm de IL-1? (p=0,0269) na córnea, entre outras alterações. Os camundongos TRPV1-/- tem fenótipo físico e ocular normal, porém reduzida sensibilidade a CAP 1µM. O tratamento com BAC leva a diminuição da secreção lacrimal (p=0,0011) e de IL-1? e TNF? na glândula lacrimal (GL) de TRPV1-/- machos (p=0,0177, p=0,0245, respectivamente). A queimadura alcalina com NaOH 1M resultou em melhor cicatrização e maior espessura epitelial no grupo TRPV1-/-. Em ix conclusão, o TRPV1 está presente na córnea e atua em resposta a agressões externas. Situações adquiridas como DM e toxicidade por BAC, reconhecidas como neuropáticas diminuem a expressão de mediadores inflamatórios. A ausência genética e TRPV1 não altera o fenótipo, mas apresenta menor sensibilidade e melhor restauração da superfície ocular após queimadura alcalina / Corneal diseases are among the leading causes of blindness.Damage and repair mechanisms are largely concentrated in the epithelium, but the mediators and targets for possible therapeutic interventions are poorly understood. The aggressions to the corneal epithelium, the activation of vanilloid receptors transient potential 1 (TRPV1) leads to inflammatory and wound healing. The aim of this study is to identify the signaling mechanisms and TRPV1 response in the cornea of experimental animals.The culture of epithelial cells from rat cornea, to identify mediators by western blot analysis, measurement of calcium influx, cytokine response measured by PCR real time (mRNA) and ELISA (protein) nocioceptivos or after inflammatory stimuli; and the histological and immunohistochemical investigation in animal models are mice with diabetes mellitus (DM) for 8 weeks, and exposed to benzalkonium chloride at 0.2% (BAC) for 7 days. Mice TRPV1-/- compared to control C57 were compared with no stimulus, or under single stimulation with 1 µM Capsaicine (CAP), BAC 0.2% for 7 days or after the alkali burn with NaOH 1 M.The results showed the presence of TRPV1 in corneal epithelium in primary culture, showed that these cells respond to calcium influx the stimulus with capsaicin agonist 1?M and increase of TNF? and IL-1? (being maximum at the CAP + CPZ combinations and Win + CAP, respectively). In rats with DM and BAC occurs reducing the expression of IL-1? mRNA (p = 0.0269) in the cornea, among other changes. The TRPV1-/- mice have physical phenotype and normal ocular but low sensitivity to CAP 1?M. Treatment with BAC leads to decreased tear secretion (p = 0.0011) and IL-1? and TNF? in the lacrimal gland (GL) of TRPV1-/- mice (p = 0.0177, p = 0.0245, respectively) . The alkaline burn with NaOH 1M resulted in better healing and greater epithelial thickness in TRPV1-/- group .In conclusion, TRPV1 is present in the cornea and operates in response to external aggressions. Situations existing as DM and xi toxicity BAC recognized as neuropathic decrease the expression of inflammatory mediators. Genetic absence and TRPV1 does not alter the phenotype, but has lower sensitivity and better restoration of the ocular surface after alkaline burn

Wong Hau Yan Connie. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 86-95). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgements --- p.ix / Contents --- p.x / List of Figures --- p.xiii / List of Tables --- p.xv / Abbreviations --- p.xvi / Chapter Chapter 1: --- Introduction / Chapter 1.1 --- Role of extracellular nucleotides in equine sweat gland epithelial cells --- p.1 / Chapter 1.2 --- Subdivision of P1 and P2 purinoceptor --- p.4 / Chapter 1.3 --- General properties of P2 purinoceptor --- p.5 / Chapter 1.3.1 --- P2X purinoceptor family --- p.5 / Chapter 1.3.2 --- P2Y purinoceptor family --- p.8 / Chapter 1.4 --- The diversity of P2Y purinoceptor --- p.10 / Chapter 1.4.1 --- P2Y1 receptor --- p.10 / Chapter 1.4.2 --- P2Y2 receptor --- p.10 / Chapter 1.4.3 --- P2Y4 receptor --- p.10 / Chapter 1.4.4 --- P2Y6 receptor --- p.10 / Chapter 1.4.5 --- P2Y11 receptor --- p.11 / Chapter 1.5 --- The importance of calcium --- p.13 / Chapter 1.6 --- General aspects of calcium signaling --- p.14 / Chapter 1.7 --- Calcium release from the intracellular calcium stores --- p.15 / Chapter 1.7.1 --- Metabolism of inositol phosphates --- p.15 / Chapter 1.7.2 --- Ca2+ release from the internal calcium store --- p.15 / Chapter 1.8 --- Store-operated calcium channels (SOCC) or Capacitative calcium entry (CCE) --- p.18 / Chapter 1.8.1 --- The nature of the signal for CCE --- p.18 / Chapter 1.8.1.1 --- Conformational coupling --- p.18 / Chapter 1.8.1.2 --- Diffusible messenger --- p.21 / Chapter 1.9 --- Mechanism of intracellular calcium measurement --- p.25 / Chapter 1.10 --- Background of E92/3 cell line --- p.28 / Chapter Chapter 2: --- Materials and methods --- p.29 / Chapter 2.1 --- Cell culture --- p.29 / Chapter 2.2 --- Preparation of the simultaneous measurement --- p.31 / Chapter 2.2.1 --- Cell seeding --- p.31 / Chapter 2.2.2 --- Dye loading --- p.33 / Chapter 2.3 --- The setup of simultaneous measurement --- p.36 / Chapter 2.4 --- Statistical analysis --- p.40 / Chapter Chapter 3: --- Results --- p.41 / Chapter 3.1 --- Major domain of Ca2+ influx is from the basolateral side --- p.41 / Chapter 3.1.1 --- Effect of store depletion by apical ATP --- p.41 / Chapter 3.1.2 --- Effect of store depletion by basolateral ATP --- p.43 / Chapter 3.1.3 --- Effect of store depletion by thapsigargin --- p.47 / Chapter 3.2 --- Differential effect of apical and basolateral nucleotides on [Ca2+]i and Isc --- p.51 / Chapter 3.2.1 --- Basolateral ATP activates an increase in [Ca2+]i but not Isc --- p.51 / Chapter 3.2.2 --- Apical and basolateral ATP activated distinct but partially overlapped internal Ca2+ pool --- p.51 / Chapter 3.2.3 --- "Dose-dependent effect of apical or basolateral ATP, UDP and UTP on [Ca2+]i i and Isc" --- p.54 / Chapter 3.3 --- P2Y receptors subtypes on the basolateral membrane --- p.60 / Chapter 3.3.1 --- "Possible involvement of P2X, P2Y1 and P2Y11 purinoceptors on the basolateral membrane" --- p.60 / Chapter 3.3.2 --- "Cross-desensitization of experiments of UTP, ATP and UDP" --- p.60 / Chapter 3.4 --- The ATP-activated Ca2+ pool and thapsigargin-activated Ca2+ pool are partially overlapped --- p.68 / Chapter 3.5 --- Anion secretion activated by Ca2+ -independent pathway --- p.74 / Chapter Chapter 4: --- Discussion --- p.76 / Chapter 4.1 --- The major membrane for the CCE is from the basolateral side --- p.76 / Chapter 4.2 --- Basolateral P2Y receptors --- p.80 / Chapter 4.3 --- Differential effects of apical and basolateral ATP --- p.82 / Chapter 4.3.1 --- Apical and basolateral ATP release Ca2+ from different pools --- p.83 / Chapter 4.3.2 --- Ca2+ -independent mechanism --- p.83 / Chapter 4.3.3 --- Other potential signaling molecules --- p.84 / Chapter Chapter 5: --- Reference --- p.86

by Keung Wing Ying. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 115-128). / Abstract also in Chinese. / Abstract --- p.I / Acknowledgments --- p.IV / Abbreviations --- p.V / List of Tables --- p.VII / List of Figures --- p.VIII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Familial Adenomatous Polyposis (FAP) --- p.1 / Chapter 1.1.1 --- Occurrence and prevalence --- p.1 / Chapter 1.1.2 --- Clinical features --- p.2 / Chapter 1.1.3 --- Laboratory studies --- p.5 / Chapter 1.1.4 --- Diagnosis --- p.6 / Chapter 1.1.5 --- Management --- p.8 / Chapter 1.2 --- Congenital Hypertrophy of the Retinal Pigment Epithelium (CHRPE) --- p.8 / Chapter 1.2.1 --- Clinical features --- p.9 / Chapter 1.2.2 --- Pathogenesis --- p.11 / Chapter 1.2.3 --- Histology --- p.12 / Chapter 1.2.4 --- Differential diagnosis --- p.13 / Chapter 1.2.5 --- CHRPE as an early clinical marker for FAP --- p.14 / Chapter 1.3 --- The Adenomatous Polyposis Coli (APC) Gene --- p.16 / Chapter 1.3.1 --- Discovery --- p.16 / Chapter 1.3.2 --- Structure and function --- p.17 / Chapter 1.3.3 --- Sequence alterations in the APC gene --- p.18 / Chapter 1.3.4 --- APC mutations associated with specific clinical features --- p.21 / Chapter 1.3.5 --- APC gene mutations in Chinese --- p.22 / Chapter 1.3.6 --- Methods for detecting mutation in the APC gene and linkage analysis --- p.23 / Chapter Chapter 2 --- Study Objectives --- p.44 / Chapter Chapter 3 --- Methodology --- p.45 / Chapter 3.1 --- Subjects --- p.45 / Chapter 3.2 --- CHRPE analysis --- p.45 / Chapter 3.2.1 --- Ophthalmoscopic examination --- p.45 / Chapter 3.2.2 --- Diagnostic criteria of CHRPE --- p.45 / Chapter 3.3 --- Materials and Equipment --- p.46 / Chapter 3.3.1 --- Enzymes --- p.46 / Chapter 3.3.2 --- DNA markers --- p.46 / Chapter 3.3.3 --- Reagent kits --- p.46 / Chapter 3.3.4 --- Primers for PCR --- p.46 / Chapter 3.3.5 --- Chemicals and reagents --- p.47 / Chapter 3.3.6 --- Radioisotopes --- p.47 / Chapter 3.3.7 --- Solutions and buffers --- p.47 / Chapter 3.3.8 --- Equipment --- p.48 / Chapter 3.4 --- Methods --- p.49 / Chapter 3.4.1 --- Blood collection --- p.49 / Chapter 3.4.2 --- DNA extraction --- p.49 / Chapter 3.4.3 --- DNA quantitation --- p.50 / Chapter 3.4.4 --- Polymerase Chain Reaction (PCR) --- p.50 / Chapter 3.4.5 --- Agarose gel electrophoresis --- p.51 / Chapter 3.4.6 --- Single Strand Conformation Polymorphism (SSCP) --- p.52 / Chapter 3.4.7 --- Direct DNA sequencing --- p.52 / Chapter 3.4.8 --- Analysis of microsatellite markers --- p.54 / Chapter Chapter 4 --- Results --- p.59 / Chapter 4.1 --- Study subjects --- p.59 / Chapter 4.1.1 --- FAP index patients --- p.59 / Chapter 4.1.2 --- FAP families --- p.59 / Chapter 4.1.3 --- Control subjects with CHRPE only --- p.60 / Chapter 4.1.4 --- Normal control subjects --- p.60 / Chapter 4.2 --- CHRPE analysis --- p.60 / Chapter 4.2.1 --- CHRPE in FAP index patients --- p.60 / Chapter 4.2.2 --- CHRPE in family members --- p.61 / Chapter 4.2.3 --- CHRPE in controls subjects --- p.61 / Chapter 4.2.4 --- Statistical analysis --- p.61 / Chapter 4.3 --- PCR optimization --- p.62 / Chapter 4.4 --- SSCP analysis of the APC gene --- p.62 / Chapter 4.5 --- Direct DNA sequencing analysis --- p.63 / Chapter 4.5.1 --- Nonsense mutations --- p.63 / Chapter 4.5.2 --- Novel silent mutations --- p.64 / Chapter 4.5.3 --- Polymorphisms --- p.65 / Chapter 4.6 --- Haplotype analysis --- p.67 / Chapter 4.7 --- Family studies --- p.67 / Chapter 4.7.1 --- Family A --- p.67 / Chapter 4.7.2 --- Family B --- p.68 / Chapter 4.7.3 --- Family C --- p.68 / Chapter 4.7.4 --- Family D --- p.69 / Chapter 4.7.5 --- Family E --- p.70 / Chapter 4.7.6 --- Family F --- p.70 / Chapter Chapter 5 --- Discussion --- p.104 / Chapter 5.1 --- The predictive value of CHRPE in FAP patients and family members --- p.104 / Chapter 5.2 --- The laboratory techniques in this study --- p.105 / Chapter 5.2.1 --- PCR optimization --- p.105 / Chapter 5.2.2 --- Single Strand Conformation Polymorphism (SSCP) --- p.106 / Chapter 5.2.3 --- Direct DNA sequencing --- p.107 / Chapter 5.3 --- Novel mutation in the APC gene --- p.108 / Chapter 5.4 --- Reported mutations in the APC gene --- p.108 / Chapter 5.4.1 --- 3183del5 --- p.108 / Chapter 5.4.2 --- R216X and R283X --- p.109 / Chapter 5.5 --- Novel silent mutations and polymorphisms in the APC gene --- p.109 / Chapter 5.5.1 --- Novel silent mutations --- p.109 / Chapter 5.5.2 --- Polymorphisms --- p.110 / Chapter 5.6 --- The relationship between APC gene mutations and CHRPE --- p.111 / Chapter 5.7 --- Haplotype analysis --- p.112 / Chapter Chapter 6 --- Conclusion --- p.114 / Chapter Chapter 7 --- References --- p.115

The maintenance of the airway/respiratory epithelium during adult homeostasis and repair and its construction during embryonic development require tightly regulated cell fate decisions. This regulation takes the form of complex transcription factor and signalling cascades, much of which are unknown, particularly in human lung development. Multiciliogenesis describes the process of specification/differentiation of airway epithelial progenitors/stem cells into mature multiciliated cells (MCCs). Here, I have identified 2 novel transcription factors, Fank1 and Jazf1 which form part of the transcription factor cascade regulating multiciliogenesis in adult and embryonic mouse tracheas. Mouse tracheal epithelium is representative of epithelium lining the entire human airway and it is possible that we will also be able to extrapolate these findings to the human airway. It is not until we fully understand the regulation of multiciliogenesis that it will be possible to look at ways of pushing basal cells towards a MCC fate for purposes of cell replacement therapy, for example in patients with mucociliary disease. As well as exploring cell fate decisions in the mouse upper airway epithelium using embryonic tracheal explants and mouse tracheal epithelial cell (MTEC) cultures, I have also explored the regulation of cell fate decisions in distal human lung epithelium at the pseudoglandular stage of development. At this stage SOX9+ distal tip cells are self-renewing and multipotent and give rise to SOX2+ stalk descendents, which differentiate into airway epithelium. The regulation of SOX9+ lung tip cell multipotency and migration of SOX2+ stalk descendents during human lung development is poorly understood. I have compared human tip (SOX9+) versus stalk (SOX2+) transcriptomes using gene ontology (GO), which has highlighted some key signalling pathways enriched in tip cells which could be important in maintaining distal tip cell multipotency. These pathways have been utilised in optimising conditions for propagating self-renewing tip-derived organoids. These organoids have the potential to be differentiated into bronchiolar and alveolar fates and as such are an invaluable research tool for studying human lung epithelial development, whilst minimising the use of human embryos and its associated ethical implications. I have also performed human tip versus mouse tip transcriptome GO analysis which highlights that although there are many similarities, there are also differences between human and mouse lung epithelium development, emphasising the need for research on human tissue.

Every year over 20,000 [3] people die as a result of being in a fire. Although flames have the biggest visual impact, it is usually the smoke produced by the combustion of natural and synthetic materials that causes more damage and claims more lives. The main constituents of smoke, both the particulate matter as well as the hot and toxic gasses, are devastating to the tracheal and lung tissues. The damage caused to the lung and trachea by inhaling this smoke can increase a fire victim's susceptibility to infectious disease significantly [1]. Between 20% and 50% of people who suffer inhalation injury contract pneumonia due to the weakened status of their body's defenses [2] and between 4,800 and 6,400 [1] people die from either pneumonia or other complications. Despite the importance of the inner-lining of the trachea to a burn victim's health and survival, current treatments consist of keeping the patient in a clean environment, supplying fresh oxygen, keeping the airways open, and letting the patient's body heal itself [1]. This treatment is not so much an active healing mechanism; rather it is a passive means of allowing the body to repair itself. The main goal of this work is to develop a minimally invasive technique that will replace lost cells on the inside surface of the trachea as efficiently as possible, actively healing the patient's injury. Ideally, the patient would receive a single treatment and then make a complete recovery on his or her own. The main challenge lies in delivering an even layer of intact cells to the inner-surface of the trachea in such a manner that they will stay in place and will replace the damaged or missing tissue. The overall approach is to spray a suspension, composed of epithelial cells in an aqueous solution of Pluronic F-127 polymer, onto the trachea using a jet atomizer. Because Pluronic F-127 solutions can be liquids at room temperature but gels at body temperature, the role of the polymer will be to immobilize the cells onto the tracheal surface long enough for them to attach and grow.

La polarité apico-basale des cellules épithéliales est requise pour le développement de l’épithélium, le maintien de son intégrité et sa fonction. Elle est définie par les relations dynamiques d’un réseau de protéines de polarité qui se localisent asymétriquement et s’excluent mutuellement pour déterminer les différents domaines corticaux. Le complexe Crumbs (Crb) est un déterminant clé du domaine apical, essentiel et suffisant pour sa définition. Patj, une protéine contenant un domaine L27 et 4 domaines PDZ, a été identifiée comme faisant partie biochimiquement du complexe Crb (via Stardust), mais sa fonction reste à préciser. Au cours de ma thèse j’ai analysé la fonction Patj chez la drosophile. La mutation Patj est létale et induit une perte de Crb de la membrane apicale dans l’épithélium folliculaire, mais pas dans l’embryon. La fonction de Patj est donc tissu spécifique. J’ai pu mettre en évidence que Patj régule positivement Crb et que les domaines PDZ1 ou PDZ4 associés au domaine L27 sont suffisants pour la fonction de Patj. J’ai de plus tenté de déterminer comment Patj régule Crb à l’échelle moléculaire. Tout d’abord, l’analyse fonctionnelle in vivo suggère que Patj régulerait la stabilité de Crb indirectement en favorisant le recrutement d’autres déterminants du domaine apical au sein du complexe. Ensuite, des approches biochimiques et génétiques ont permis de montrer qu’en plus d’interagir indirectement avec Crb, Patj interagit aussi directement via ces domaines PDZ1 et PDZ4. Ces données permettent de proposer un modèle mécanistique dans lequel Patj en liant à la fois Sdt et Crb formerait des dimères de Crb, qui en association avec sa dimèrisation extracellulaire déjà connue permettrait la formation d’oligomères de Crb à la membrane apicale. L’oligomérisation de Crb favoriserait son activité de déterminant apical. De plus, j’ai observé une redondance entre Patj et Lin-7, un autre membre du complexe Crb, dans la polarité apico-basale, une telle fonction pour Lin-7 n’ayant pas encore été reportée. Ainsi, mes travaux apportent de nouveaux éléments pour la compréhension de la polarité épithéliale. / Apico-basal polarity is required for epithelium development, function and integrity. Polarization is defined by a network of polarity proteins that are localized asymmetrically and the dynamic interplay between them. Crb is a key determinant of the apical domain, necessary and sufficient for its identity. Patj, a protein containing a L27 domain and four PDZs domains, has been identified as a core component of the Crb complex, as it interacts with Crb through Sdt. But its function remains elusive. During my thesis I investigated Patj function in Drosophila. Patj mutation is lethal and induces a decrease of Crb from the apical domain in the follicular epithelium, but not in embryonic epithelium. Thus, Patj function is tissue-specific. Patj positively regulates Crb, and the PDZ1 or PDZ4 together with the L27 domain of Patj are sufficient for its function. Then, I focused on the molecular mechanism underlying Crb regulation. In vivo analysis suggests that Patj regulates Crb stability indirectly by modulating its ability to recruit apical proteins. Biochemical and genetics analyses allow showing that in addition of its indirect interaction through Sdt, Patj interacts directly with Crb through its PDZ1 and PDZ4. Extra-cellular dimerisation of Crb is involved in a feedback promoting its apical localization. Patj with Crb direct interaction could participate to this feedback via an intra- cellular dimerisation, allowing Crumbs oligomerisation at the apical membrane. In addition, I have seen that Patj is redundant with Lin-7, another core component of Crb complex, for apico- basal polarity. In conclusion my thesis work provides new clues for the understanding of epithelial polarity regulation.

Infants born prematurely are a vulnerable population with diverse nutritional needs to battle their increased risk of gastrointestinal (GI) diseases. Human milk is considered the 'gold standard' of infant nutrition. Human milk not only provides nutrition for newborn growth, but contains bioactive components which contribute to GI maturation, immune protection and neurological development. Among these bioactive components are extracellular vesicles known as exosomes. Exosomes are double-lipid membrane vesicles containing mRNA, microRNA and proteins, secreted by cells as a form of cell-to-cell communication. Human milk exosomes contain immune-related microRNA and proteins that withstand in vitro simulated human digestion, suggesting that signals are being delivered to the cells residing in the GI tract of a newborn. In premature birth, disruption of GI tract maturation predisposes the infant to increased susceptibility of GI inflammatory diseases. To prevent inflammation, immune tolerance in the GI tract of premature infants should be promoted and I hypothesized that exosomes differ between preterm and term milk, and may contribute to the anti-inflammatory effects of human milk. Human milk exosomes from mothers who gave birth to term or preterm infants were characterized based on size, surface protein markers and total protein. Preterm milk exosomes contained a more diverse protein profile. The effects of milk exosomes on intestinal epithelial cells were observed in an in vitro model using Caco-2/15 cells. Milk exosomes were able to attenuate the inflammatory response induced by heat-killed bacteria as measured by the transcription of pro-inflammatory cytokines.

Age-Related Macular Degeneration (AMD) is a retinal eye disease that is the leading cause of blindness in those over 50 years of age throughout the developed world. Oxidative and metabolic dysfunction of the retinal pigment epithelium (RPE) has been shown to play an important role in AMD. However, the mechanism of dysfunction in the RPE is poorly understood. The peroxisome proliferator-activated receptor-gamma coactivator 1α and β (PGC1A and PGC1B) are coactivators that interact with transcription factors to regulate mitochondria metabolism. In a previous study, it was demonstrated that one of the isoforms, PGC1A, protects RPE cells from oxidative stress through the upregulation of transcription factors that regulate important antioxidant enzymes. There is experimental and clinical evidence that demonstrates that PGC1B may play a deleterious role in the RPE cell. The objective of this study is to characterize the pathological effect of PGC1B on the RPE cell. PGC1B was overexpressed in the human retinal pigment epithelium cell line (ARPE-19) and expression of the PGC1 isoforms and their main gene targets was evaluated using quantitative polymerase chain reaction (qPCR). Cell death was evaluated under basal and pro-oxidant conditions by quantification of lactate dehydrogenase (LDH) release from the RPE cell. The effect of PGC1B gain of function on the RPE pro-angiogenic function was evaluated using the choroid explant sprouting assay and by testing the proliferative, migratory, and tube formation potential of RPE-derived conditioned media on the rhesus monkey chorioretinal cell line (RF/6A). Quantitative PCR analysis showed that overexpression of PGC1B in ARPE-19 cells leads to increased mitochondrial metabolism and decreased antioxidant enzyme expression, causing oxidative stress. After treatment with H2O2, PGC1B overexpression caused ARPE-19 cells to become more susceptible to cytotoxicity. The ex vivo choroid sprouting assay demonstrated that PGC1B overexpression in RPE is pro-angiogenic. However, cell proliferation as measured by MTT and the cell migration assay provided conflicting results on the pro-angiogenic effect of PGC1B. Previous research has demonstrated that oxidative stress in the RPE cell plays a role in AMD progression. It has been demonstrated in this study that PGC1B expression leads to increased mitochondrial metabolism and repression of antioxidant enzymes needed to prevent oxidative stress and dysfunction in the RPE cell. While experiments to test the effect of PGC1B on angiogenesis provided conflicting results, a different endothelial cell model may be better suited in demonstrating the pro-angiogenic effect of PGC1B. The hope is that the information provided from this study may be used to further our understanding of AMD and lead to the development of therapeutic targets to combat the effects of AMD.

Orientador: Eliane Morielle Versute / Banca: Luciana Bolsoni Lourenço Morandini / Banca: Mary Massumi Itoyama / Resumo: A ordem Chiroptera constitui a segunda maior ordem de mamíferos e está classicamente dividida em duas subordens: Megachiroptera e Microchiroptera. A primeira é encontrada exclusivamente no Velho Mundo e compreende uma única família (Pteropodidae) com 42 gêneros e 185 espécies, enquanto que a segunda está amplamente distribuída por todo o globo, envolvendo 17 famílias, 157 gêneros e 928 espécies. Apesar dos morcegos serem extraordinariamente bem sucedidos, eles permanecem como um dos grupos menos conhecidos em relação a aspectos como: processos evolutivos, mecanismos reprodutivos e características nucleolares. Embora o processo de espermatogênese tenha sido objeto de estudo em muitos mamíferos, pouca atenção tem sido dada a esse estudo em morcegos, apesar dessa ser uma grande e diversa classe de organismos, que apresenta diferentes estratégias reprodutivas para ajustar esses animais às várias condições ecológicas e comportamentais as quais estão submetidos. Da mesma forma, em geral todas as observações sobre regiões organizadoras nucleolares (RONs) e nucléolos em morcegos foram feitas a partir da análise de células somáticas. Assim, devido à escassez de informações referentes à espermatogênese e a nucleologênese em Chiroptera e ao interessante e vasto campo de conhecimento que esses aspectos representam, o intuito do presente estudo foi analisar as células dos túbulos seminíferos das espécies de morcegos, Resumo 136 Artibeus lituratus, Artibeus planirostris, Carollia perspicillata, Platyrrhinus lineatus (Phyllostomidae) e Myotis nigricans (Vespertilionidae), por diferentes técnicas histológicas, citoquímicas e moleculares. Três tipos de espermatogônias foram reconhecidos baseado no grau de condensação da cromatina e morfologia nuclear, espermatogônias Ad, Ap e B. Essas ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The order Chiroptera is the second largest order of mammals and is classically divided into two suborders: Megachiroptera and Microchiroptera. The first is found exclusively in the Old World, and contains a single family (Pteropodidae) with 42 genera and 185 species, while the second is widely distributed around the world, concerning 17 families, 157 genera and 928 species. Despite of the bats are extraordinarily successful, they remain as one of the least recognized groups on aspects such as: evolutionary processes, reproductive patterns and nucleolar characteristics. Although the process of spermatogenesis has been the subject of study in many mammals, little attention has been given to this study in bats, a large and diverse class of organisms, which presents different reproductive strategies to adjust these animals to different ecological and behavioral conditions that they are submitted. In the same way, in general all studies concerning nucleolar organizer regions (NORs) and nucleoli in bats were made from the analysis of somatic cells. Thus, due to the scarcity of information regarding spermatogenesis and nucleologenesis in Chiroptera and the interesting and vast field of knowledge that these things represent, the purpose of this study was to analyze the cells of the seminiferous tubules of the species of bats, Artibeus lituratus, Artibeus planirostris, Carollia perspicillata, Platyrrhinus lineatus (Phyllostomidae) and Myotis nigricans (Vespertilionidae), by different histological, molecular and citochemical techniques. Three types of spermatogonia were recognized Abstract 140 based on the chromatin condensation and nuclear morphology, type Ad, type Ap and B. These, undergo meiosis, passing through the two cellular divisions and forming haploid spermatids, which undergo differentiation, condensing its DNA, elongating its nuclei and forming the flagellum and acrossomo,...(Complete abstract click electronic access below) / Mestre