Neurogenesis is the process by which functionally integrated neurons are generated from progenitor cells. In the adult mammalian brain two sites of high density cell division have been identified that contain neural progenitor cells retaining the ability to generate new neurons: the subgranular zone of the hippocampus (SGZ) and the subventricular zone (SVZ) lining the lateral ventricles in the forebrain. Several studies have suggested that SVZ neural progenitor cells in the adult brain can migrate into regions other than the olfactory bulb after either administration of growth factors, induction of neuronal cell loss or injury. Brain-derived neurotrophic factor (BDNF) and fibroblast growth factor (FGF-2) play major roles in regulating the survival and fate of progenitor cells in the adult mammalian brain. To determine the effect of BDNF or FGF-2 on neurogenesis in the injured adult brain, BDNF or FGF-2 were over-expressed in the subventricular zone (SVZ) via recombinant adeno-associated virus (AAV1/2) delivery and newly generated cells were identified using bromodeoxyuridine (BrdU; 150mg/kg intraperitoneal) labelling. Selective striatal cell loss was induced in a subgroup of rats by unilateral striatal injection of the excitotoxin quinolinic acid (QA) 21 days after AAV1/2 injection and 24 hours prior to BrdU labeling. The results of this thesis demonstrate that BDNF augments the recruitment, neuronal differentiation and survival of progenitor cells in both neurogenic and non-neurogenic regions of the unlesioned or QA lesioned brain. BDNF also appears to contribute to the persistence of newly generated neurons in the QA lesioned striatum. Our results provide the first evidence demonstrating the neurogenic effect of BDNF on compensatory striatal neurogenesis in the injured adult brain and suggest that enhanced BDNF expression may be a viable strategy for inducing or augmenting endogenous neural progenitor cell neurogenesis. Unlike the effect of BDNF, FGF-2 appears to have no effect on proliferation and/or survival of neural progenitor cells in either the normal or damaged brain. FGF-2 appears to be unable to act as a positive mediator of SVZ progenitor cell proliferation and neurogenesis in this study. However, FGF-2 may be having an inhibitory effect on progenitor cell differentiation. The negative result of the FGF-2 study may be of major significance in indicating the potential requirement of additional factors interacting with FGF-2 to influence neurogenesis. The results from the FGF-2 study contribute to the research field in highlighting the complexity of the mammalian neurogenic process. This thesis highlights the need for further investigation into multiple factor interactions, tighter regulation of the transgenic protein expression from the AAV1/2 delivery vector or alternative progenitor cell labelling paradigms. However, it does show that if neurogenesis can be induced or augmented exogenously, neural progenitor cells may provide a substrate for repair in the adult brain and dramatically change therapeutic approaches towards the treatment of neurodegenerative diseases.

Orientador: Iscia Lopes Cendes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T07:28:20Z (GMT). No. of bitstreams: 1 Paiva_RejaneScolariRezende_D.pdf: 1128972 bytes, checksum: 7861376a51c6236c8ecffe342b18ce56 (MD5) Previous issue date: 2006 / Resumo: Com o avanço da genética molecular, hoje é possível detectar alterações genéticas específicas responsáveis por várias doenças, até mesmo antes de o indivíduo manifestar qualquer sintoma. Assim, testes genéticos podem ser realizados para a confirmação diagnóstica, o teste diagnóstico (TD) e para a realização de testes pré-sintomáticos ou teste preditivo (TP). Neste trabalho abordamos questões relacionadas ao TP, para dois grupos de doenças neurodegenerativas: a doença de Huntington (DH) e as ataxias espinocerebelares (AEC). Ambas são doenças degenerativas, progressivas, geralmente familiares, cujos sintomas se iniciam em idade variada entre a primeira e a quinta década de vida, progridem lentamente, levando ao óbito após 15 a 20 anos. Nossos objetivos principais foram: a) determinar o perfil psicológico dos usuários do TP, b) conhecer as motivações que levam os indivíduos a realizarem o teste preditivo, c) avaliar psicologicamente estes indivíduos para determinar se os mesmos se encontram preparados para se submeterem ao teste molecular preditivo. Procuraram o serviço para a realização do TP 38 indivíduos que tinham a confirmação molecular de um membro da família afetado pela DH ou AECs. A maioria (n=23) dos indivíduos interessados no TP, estavam em risco para a doença de Huntington e 40% (n=15) para ataxia. Sessenta e seis por cento (n=10) dos indivíduos em risco para ataxia tem história familiar e confirmação molecular para a Doença de Machado-Joseph. Destes 38 indivíduos que procuraram o serviço, apenas 34% (n=13) concluíram o protocolo do TP e 50% (n=19) interromperam o mesmo. Para 16% (n=6) dos indivíduos que requisitaram uma consulta, o interesse foi obter informações referentes ao risco de transmissão, bem como a conduta para a realização do teste. O objetivo dos usuários em realizar o TP foi para 38% (n=5), o planejamento familiar. Para 32% (n=4) receber o resultado do teste foi importante para reduzir a incerteza sobre ser portador da mutação e assim poder planejar o futuro sem a preocupação de desenvolver a doença neurodegenerativa presente em toda sua vida. Já para 23% (n=3) dos usuários do TP, a grande motivação foi querer descartar o risco para a prole e para 7% (n=1) o planejamento profissional foi questão a ser resolvida após o resultado do TP. Com este trabalho pudemos concluir que os indivíduos que realizaram o TP estão com a vida afetiva, profissional e financeira estável. Além disso, não houve diferença nos resultados no que diz respeito às condições físicas e emocionais destes usuários que se submeteram a avaliação depois de conhecerem o resultado / Abstract: Recent advances in molecular genetics have made it possible to detect specific genetic alterations that are responsible for several diseases, even before the individual presents any symptoms. Hence, genetic tests such as the diagnostic test (DT) to confirm diagnosis and the predictive test (PT) or presymptomatic test can be performed. This study deals with the PT aspects of two neurodegenerative diseases: Huntington¿s disease (HD) and spinocerebellar ataxias (SCA). Both are degenerative, progressive, generally familial diseases with onset of symptoms between the first and fifth decade of life, progressing slowly to death after 15 to 20 years. Our main objectives were: a) determine the psychological profile of PT users; b) study the reasons that lead individuals to undergo predictive testing; c) psychological assessment of these individuals to check if they are prepared to undergo molecular testing. Thirty-eight individuals having a family member affected by HD or SCA came to this service for testing. Their ages ranged from 17 to 53 years, their educational levels were middle school, high school and university, 58% (22) were females. More than half of the individuals (n=23) interested in undergoing the PT presented a risk for Huntington¿s disease and 40% (n=15) for ataxia. Sixty percent (n=10) of the individuals with a risk for ataxia had molecular testing confirmation for Machado- Joseph Disease. Only 34% (n=13) of the 38 individuals concluded the PT protocol, while 50% (n=19) did not. Sixteen percent (n=06) of the individuals who requested a consultation were only interested in information about risk of transmission and the test procedure. The test users presented a 38% risk for Huntington¿s disease and 62% (n=8) risk for ataxia. Fifty percent of the ataxia test users presented a risk for type 3 or Machado-Joseph disease. In the case of 38% (n=5) of the users, their main purpose in performing the PT test was family planning. However, one individual already had a child, but wanted to plan a second child if he was not a carrier of the mutation responsible for the disease in his family. The test results were important for 32% (n=4) of these individuals because they cleared doubts about being mutation carriers, which meant they could plan the future without worrying about developing a neurodegenerative disease. In the case of 23% (n=3) PT users, the main reason was to discard any risk in relation to their offspring and in the case of 7% (n=1), their professional planning could be done based on the results. Hence, we can conclude that an organized protocol offering genetic counseling and pre-test services is needed so that individuals who would like to undergo the PT are able to evaluate the consequences of this test and their reasons for performing the test / Doutorado / Genetica Medica / Doutor em Ciências Médicas

Magister Pharmaceuticae - MPharm / Neurodegenerative diseases are multifactorial in nature, and taking the complex nature of these disorders into consideration, multi-target directed ligands may present as better options to treat these disorders than the classic ‘one molecule, one target’ approach. Neurotransmitter amines are catabolized by monoamine oxidase A and B (MAO-A and MAO-B), therefore they have been targeted for the treatment of neuropsychiatric and neurodegenerative diseases. Besides offering a potential antidepressant action in PD, MAO-A inhibitors may also provide a symptomatic benefit by reducing MAO-A-catalysed oxidation of dopamine. The oxidative deamination reaction catalyzed by MAO-B is one of the major catabolic pathways of dopamine in the brain. Inhibition of this enzyme leads to enhanced dopaminergic neurotransmission and are currently used in the symptomatic treatment of PD. Furthermore, MAO-B inhibitors may also exert neuroprotective effects by reducing the concentration of potentially hazardous by-products produced by MAO-B-catalysed dopamine oxidation. Apoptosis or programmed cell death occurs in a number of neurodegenerative disorders and it has been proven that inhibition of the executing enzyme, caspases-3, slows down or even stops apoptosis. Having this in mind we focused on the propargylamine function of selegiline and the fluorophenyl function of safinamide, because of their inherent monoamine oxidase inhibitory activities; and isatin as a non-peptide inhibitor of caspase-3. Therefore we attempted to design and synthesize multifunctional hybrid molecules acting simultaneously to halt the apoptotic neuronal breakdown process and eliminate the signs and symptoms of diseases such as PD. Seven novel compounds were successfully synthesized utilizing multistep processes. The synthesis of 5 chlorosulfonyl isatin was accomplished starting from the commercially available isatin in two steps, which were, sulfonation using tetramethylene sulfone and chlorination with POCl₃. Next 5-chlorosulfonyl isatin was conjugated to the fluorophenylamine derivative with the fluoro-function at either the ortho, meta or para position through a nucleophilic substitution reaction on the chlorosulfonyl position. The resultant compounds were coupled on the N position of the isatin function with propargyl bromide, using a microwave synthesis procedure, in a nucleophilic substitution reaction. The structures and purity were confirmed by nuclear magnetic resonance (NMR) and mass spectrometry (MS). In the biological evaluations recombinant human MAO-A, MAO-B and caspase 3 enzymatic assays were performed to determine the activity of the novel compounds at an enzymatic level. The inhibition percentages for these compounds were calculated and plotted against the logarithm 8 of the inhibitor concentrations to obtain a sigmoidal dose-response curve and consequently the IC50 value. The synthesized compounds showed inhibition of the MAO-A, MAO-B and caspase-3 enzymes at low to high micro molar concentrations. The role of the fluorophenylamine moiety in the synthesized compounds was significant for their multifunctional activity as shown by compounds 3 and 4 having good inhibitory activity towards MAO-A, MAO-B and also excellent inhibitory activity against caspase 3, making those ideal candidates for further lead compound development and multifunctional drug design. The introduction of the propargylamine moiety only increased the MAO-A inhibitory activity; this was shown by compounds 7, 8 and 9 which exhibit good MAO-A selectivity with low MAO-B and caspase-3 inhibitory activities.

No description available.

Thesis (Ph. D.)--University of Virginia, 1999. / Spine title: Mitochondria in AD & PD models. Includes bibliographical references (p. 146-159). Also available online through Digital Dissertations.

L'âge, les facteurs de risque vasculaire, l'inactivité physique sont connus comme facteurs de risque des syndromes démentiels.Le sommeil joue un rôle majeur dans la physiologie cérébrale. Le syndrome d'apnée du sommeil (SAS) est une pathologie fréquente chez les sujets âgés, surtout chez ceux souffrant de pathologie démentielle. Les études chez les patients atteints d'hypertension, et/ou de fibrillation atriale montrent une prévalence 2 à 3 fois plus élevée de SAS. Le cerveau et sa vascularisation forment un ensemble avec le coeur et les poumons qui fournissent l'apport en énergie et en oxygène. Une dynamique harmonieuse entre ces trois organes est nécessaire au fonctionnement physiologique du cerveau et un dysfonctionnement de cet ensemble pourrait engendrer une altération cognitive. Ce travail a pour but d'analyser les liens entre l'altération du débit vasculaire de la macro-circulation témoin de l'activité cardiaque, la pulsatilité du liquide céphalospinal reflétant l'hydrodynamique cérébrale, les paramètres respiratoires en lien avec les apnées du sommeil, et le statut cognitif du sujet âgé. En nous basant sur les résultats des bilans clinique, biologique, neuropsychologique, de l'imagerie par résonnance magnétique (morphologie et flux), des holters tensionnel et rythmique dans une population de 95 patients âgés cognitivement altérés, nous avons analysé les relations entre les paramètres concernant le cerveau, le coeur et les poumons. Cette approche révèle une relation entre ces trois systèmes et la cognition. La découverte d'une prévalence de plus de 70% de SAS dans cette population associée à d’autres résultats inattendus devrait faire l'objet de travaux ultérieurs / Age, vascular disorders, and lack of physical activity are known risk factors for dementia syndromes. Sleep has an important role in cerebral physiology. Sleep apnea syndrome (SAS) is common in elderly patients, especially in those with dementia. It was reported that the prevalence of SAS is 2 to 3 times higher in patients with arterial hypertension and/or atrial fibrillation. The brain and its vascular system cannot be considered separately from the heart and the lungs, which provide energy and oxygen supply. Cognitive alterations do not reflect the function of the brain only, and balanced dynamics between all these organs is necessary to maintain neurological functions. Therefore, the aim of this dissertation was to analyze the impact of altered cerebral blood flow in macrocirculation reflecting cardiac activity, pulsatility of the cerebrospinal fluid reflecting cerebral hydrodynamics, and SAS reflecting respiratory function on the cognitive status of elderly patients. Based on a clinical examination, geriatric and neuropsychological assessment, blood tests, structural magnetic resonance imaging, phase-contrast magnetic resonance imaging, 24-hour ambulatory blood pressure measurement, and 24-hour electrocardiogram in the population of 95 elderly patients aged 75 years and older, and suffering from neurodegenerative diseases, we analyzed the correlations between the neurological, cardiac, and respiratory parameters. This approach allowed an identification of associations between the abnormalities in these 3 systems and cognitive function. An unexpected finding, among some other abnormalities, was the prevalence of SAS exceeding 70%, which will be the subject of future research

Many neurodegenerative disorders are characterised by protein misfolding and subsequent amyloid fibrillisation and deposition. Amyloid-beta peptide (Aβ) was found to be the main constituent of the extracellular amyloid plaques of Alzheimer’s disease (AD) in the 1980s. What triggers amyloid formation or inhibits it are of particular interest. This thesis focuses on the effect of endogenous proteins and molecules on amyloid fibrillisation. In Chapter 3, I show that at physiological micromolar levels found in the cerebrospinal fluid, human serum albumin inhibits the rate of Aβ fibrillisation. Indeed in vitro the amount of amyloid fibres generated directly correlates to the proportion of Aβ not competitively bound to albumin. Albumin binds cholesterol and fatty acids in vivo, both of which have been linked with an increased risk of developing AD. In Chapter 4, I show Aβ competes with these molecules for albumin binding, so disrupting albumin’s ability to inhibit Aβ fibrillisation. My observations suggest a significant role for albumin regulating Aβ fibril growth. Albumin also binds Cu2+ in vivo with a tight picomolar affinity. Animal models suggest disrupted Cu2+ homeostasis potentiate AD phenotype. In Chapter 5, I show that regardless of Aβ alloform or fibrillisation stage, the affinity for Cu2+ is in the ~20 picomolar range but weaker than albumin. Circular Dichroism spectroscopy in the visible region (Vis-CD) is a powerful technique to study metal-protein interactions. In Chapter 6, I develop a set of empirical rules that relates the appearance of particular Vis-CD spectral features to the conformation of the complex. These rules are used to gain insight into Cu2+-protein complexes in Prion disease and Parkinson’s disease. I show the N-terminal amino group of cellular prion protein (PrPC) has a tighter affinity for Cu2+ than the individual octa-repeat binding sites present within PrPC and show for the first time that Cu2+ loads on to the N-terminal amino group before the single octa-repeat binding sites. I determine the affinity of Cu2+ for model N-terminal peptides of alpha-synuclein of Parkinson’s disease and show that side- chain coordination stabilises the complex and increases the affinity for copper compared to main-chain coordination only. This thesis highlights the importance of overlapping interactions with endogenous proteins and molecules in the development of neurodegenerative disease. Indeed, the amyloid protein binding partners studied here are all co-localised at the synapse thus future in vitro studies of neurodegenerative disease should consider the complex nature of interactions possible in situ.

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases. It is characterized by the presence of intracellular inclusions termed Lewy bodies (LBs) and Lewy neuritis (LNs) in the brain, in which α-Syn aggregates constitute the main component. Therefore, α-Syn aggregation was implicated in the pathogenesis of PD. Structurally α-Syn is a disordered protein with little ordered structure under physiological conditions. However, research of α-Syn has provided substantial information about its structural properties. The precise function of α-Syn is still under investigation. Research has also shown that metals, such as copper and iron, accelerate α-Syn aggregation and fibrillation in vitro and are proposed to play an important role in vitro. In this study, isothermal titration calorimetry was used to determine iron binding properties to α-Syn revealing the presence of two binding sites for iron with an affinity of 1.06 x 105 M-1 and a dissociation constant of ~ 10μM which is physiologically relevant to iron content in the brain. In addition, α-Syn was found to reduce iron in the presence of copper. This property was demonstrated via ferrozine based assay. In vitro, thoflavin-T fluorescence assay was used to investigate the mechanism by which metals induce α-Syn aggregation and whether it is related to metal binding. Metals, mainly copper and iron, caused 2-fold increase in the aggregation rate of WT α-Syn and its metal binding mutants. Linking that to the increased metal content in the brain, α-Syn aggregation can cause changes in tissue composition, thus altering the normal functional environment in the brain. Moreover, western blotting analysis showed that copper increases the aggregate formation in mammalian dopaminergic cells over-expressing α-Syn.

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / "May 1998." Typescript. Vita. Includes bibliographical references (leaves 176-210). Also available on the Internet.

Thesis (Ph.D.)--University of Florida, 2005. / Typescript. Title from title page of source document. Document formatted into pages; contains 142 pages. Includes Vita. Includes bibliographical references.