Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-03-02T20:23:00Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_cristina_resende_camargos.pdf: 3572613 bytes, checksum: ed282931c95236a0305016db8c75f026 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-03-06T11:37:07Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_cristina_resende_camargos.pdf: 3572613 bytes, checksum: ed282931c95236a0305016db8c75f026 (MD5) / Made available in DSpace on 2017-03-06T11:37:08Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ana_cristina_resende_camargos.pdf: 3572613 bytes, checksum: ed282931c95236a0305016db8c75f026 (MD5) Previous issue date: 2016 / A obesidade infantil ? considerada um dos maiores problemas de sa?de p?blica do mundo. Estudos demonstram altera??o do padr?o de secre??o de adipocinas, cortisol e do fator neurotr?fico derivado do c?rebro (BDNF), bem como inflama??o cl?nica cr?nica sublimiar e desequil?brio redox em crian?as com sobrepeso e obesidade na idade escolar. Al?m disso, o excesso de peso tamb?m est? associado a reduzido desenvolvimento cognitivo e motor. Apesar da literatura indicar que os primeiros 24 meses de vida representam um per?odo importante para o desenvolvimento da obesidade infantil, n?o existem evid?ncias se crian?as com sobrepeso e obesidade nesta faixa et?ria j? apresentam altera??es em par?metros neuroend?crino-inflamat?rios, com poss?vel impacto no desenvolvimento infantil. Dessa forma, os objetivos deste estudo foram: 1) analisar as concentra??es plasm?ticas de adipocinas e BDNF, as concentra??es s?ricas de cortisol e o estado redox de crian?as com sobrepeso/obesidade entre seis e 24 meses de idade; 2) avaliar o desenvolvimento cognitivo e motor de crian?as com sobrepeso/obesidade entre seis e 24 meses de idade e; 3) verificar associa??es entre os biomarcadores avaliados com o desenvolvimento cognitivo e motor nessa faixa et?ria. Foi realizado um estudo transversal com crian?as com sobrepeso/obesidade e eutr?ficas entre seis e 24 meses de idade, cadastradas nas Estrat?gias de Sa?de da Fam?lia. As concentra??es plasm?ticas de leptina, adiponectina, resistina, receptores sol?veis do fator de necrose tumoral 1 e 2 (sTNFR1 e sTNFR1), BDNF e as concentra??es s?ricas de cortisol foram mensuradas pelo m?todo ELISA. As quimiocinas foram mensuradas pela t?cnica cytometric bead arrays e o estado redox foi determinado por meio da detec??o das concentra??es de subst?ncias reativas ao ?cido tiobarbit?rico (TBARS), da atividade das enzimas catalase (CAT) e super?xido dismutase (SOD) e da habilidade de redu??o do ferro (FRAP). O desenvolvimento infantil foi avaliado por meio do instrumento Bayley Scales of Infant and Toddler Development, 3? edi??o (Bayley-III). Foi utilizado teste t para amostras independentes para comparar os grupos e correla??o de Pearson ou Spearman para verificar a associa??o entre as vari?veis. Al?m disso, foi utilizado um modelo de regress?o linear m?ltipla stepwise para verificar a associa??o entre os biomarcardores selecionados com o desenvolvimento cognitivo e motor. As concentra??es plasm?ticas de leptina (p=0,0001), adiponectina (p=0,0007), BDNF (p=0,003) e as concentra??es s?ricas de cortisol (p=0,048) foram significativamente superiores no grupo de crian?as com sobrepeso/obesidade. Em contrapartida, as crian?as deste grupo apresentaram menores concentra??es de TBARS (p=0,004) e menor atividade das enzimas antioxidantes CAT (p=0,045) e SOD (p=0,02). N?o foram encontradas diferen?as significativas nas concentra??es de quimiocinas, sTNFR1, sTNFR2, resistina e FRAP entre os grupos (p>0,05). Al?m disso, as crian?as do grupo sobrepeso/obesidade apresentaram menores escores de desenvolvimento cognitivo (p=0,03) e motor (p=0,04). Foi ainda encontrada associa??o significativa entre as concentra??es plasm?ticas de leptina e sTNFR1 com o escore composto cognitivo (p=0,001) e das concentra??es plasm?ticas de sTNFR1 com o escore composto motor (p=0,003). Todos esses resultados apontaram a presen?a de altera??es neuroend?crino-inflamat?rias em crian?as com sobrepeso/obesidade entre seis e 24 meses de idade. Al?m disso, embora a maior parte das crian?as com sobrepeso/obesidade apresentem desenvolvimento infantil dentro dos limites de normalidade, evidencia-se pior desempenho cognitivo e motor. Por fim, foi demonstrado que maiores concentra??es de sTNFR1 e menores concentra??es de leptina foram associadas com melhores desfechos de desenvolvimento infantil nessa faixa et?ria. / Tese (Doutorado) ? Programa Multic?ntrico de P?s-Gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Childhood obesity is one of the world?s most serious public health issues. Studies have demonstrated dysregulated secretion pattern of adipokines, cortisol, brain-derived neurotrophic factor (BDNF), as well as chronic low-grade inflammation and redox imbalance in school-age overweight or obese children. Overweight/obese infants also had lower cognitive and motor development scores. Although the literature points out that the first 24 months of life represent an important period for the development of childhood obesity, it is not known whether overweight/obese infants in this age interval present alterations in neuroendocrine inflammatory parameters, with possible impact on child development. Then, the objectives of this study were: 1) to analyze the plasmatic levels of adipokines and BDNF, serum cortisol and redox status in overweight/obese infants between 6 and 24 months of age; 2) to evaluate the cognitive and motor development in overweight/obese infants between 6 and 24 months of age and; 3) to verify the association of the biomarkers evaluated with cognitive and motor development in this age interval. A cross-sectional study was conducted with infants with overweight/obesity and normal-weight between 6 and 24 months enrolled in Family Health Strategies. Plasma leptin, adiponectin, resistin, BDNF, soluble tumour necrosis factor receptors 1 and 2 (sTNFR1, sTNFR2), and serum cortisol levels were measured using conventional ELISA kits. Plasma chemokines were measured using the cytometric bead arrays kit, and oxidative stress was assessed by thiobarbituric acid reactive substances (TBARS) concentration, enzymes catalase (CAT) and dismutase superoxide (SOD) activity, as well by ferric reducing antioxidant power (FRAP). Infant development was performed using the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III). A t test for independent samples was performed to compare the groups and Pearson and Spearman correlation was used to verify the association between parameters. Multiple linear stepwise regression models were utilized to verify the association between the biomarkers selected and cognitive and motor composite scores. Plasma levels of leptin (p=0.0001), adiponectin (p=0.0007), BDNF (p=0.003) and serum cortisol (p=0.048) were significantly higher in overweight/obese infants. In contrast, concentration of TBARS (p=0.004), CAT (p=0.045) and SOD activity (p=0.02) were lower in overweight/obese infants. There were no differences in the levels of chemokines, sTNFR1, sTNFR2, resistin and FRAP between groups (p>0.05). Moreover, overweight/obese infants had lower cognitive (p=0.03) and motor (p=0.04) development scores than normal-weight infants. A significant association of plasma leptin and sTNFR1 levels with cognitive composite scores (p=0.001) were found and plasma sTNFR1 levels were associated with motor composite scores (p=0.003). All these results point out neuroendocrine inflammatory response changes in overweight/obese infants between 6 and 24 months. Moreover, although most of overweight/obese infants have presented cognitive and motor development within normal limits, there is evidence of worse cognitive and motor performance. Finally, high sTNFR1 and low leptin levels were associated with increase developmental outcomes in infants in this age interval.

Submitted by VÍTOR BONETTI VALENTE null (vitorbvalente89@hotmail.com) on 2016-10-14T20:59:55Z No. of bitstreams: 1 Dissertação - Vitor B. Valente_Versão Definitiva.pdf: 1948563 bytes, checksum: 03b2d1c12fa8b8b2c7b0c39faf9bb490 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-19T19:14:01Z (GMT) No. of bitstreams: 1 valente_vb_me_arafo_par.pdf: 678709 bytes, checksum: 264cdeca2ea5cfd220b36a541cd5ae2c (MD5) / Made available in DSpace on 2016-10-19T19:14:01Z (GMT). No. of bitstreams: 1 valente_vb_me_arafo_par.pdf: 678709 bytes, checksum: 264cdeca2ea5cfd220b36a541cd5ae2c (MD5) Previous issue date: 2016-09-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Evidências mostram que os hormônios relacionados ao estresse podem influenciar a progressão do câncer, mas o papel destes mediadores sobre o processo de carcinogênese no microambiente tecidual, em condições naturais, é pouco compreendido. Neste estudo, nós utilizamos um modelo de carcinogênese bucal em ratos para testar a hipótese de que os níveis de hormônios relacionados ao estresse no microambiente tecidual em condições naturais (sem estresse) pré-indução carcinogênica influenciam a ocorrência e progressão do carcinoma espinocelular (CEC) de língua. Quarenta e oito ratos machos Wistar foram submetidos a uma biópsia de tecido lingual normal previamente à indução carcinogênica e os níveis teciduais de norepinefrina, corticosterona, ACTH e BDNF foram mensurados. Três semanas depois os animais foram tratados com o carcinógeno químico 4-nitroquinolina-1-óxido (4NQO) por 20 semanas e a ocorrência de CEC ou Leucoplasia (lesão precursora do CEC) na língua foi analisada microscopicamente. Níveis basais aumentados pré-carcinogênese de norepinefrina e BDNF e níveis reduzidos de corticosterona foram preditivos para ocorrência de CEC. Níveis basais elevados de norepinefrina foram associados à uma expressão reduzida de RNAm para CDKN2a-p16 nos CECs. Níveis teciduais de corticosterona e BDNF nas leucoplasias e corticosterona no CEC foram significativamente mais elevados em relação a mucosa normal pré-carcinogênese. Níveis elevados de norepinefrina no microambiente dos CECs foram associados a um maior volume e espessura do tumor. Da mesma forma, níveis elevados de norepinefrina, ACTH e BDNF no CEC foram associados a uma menor intensidade do infiltrado linfoplasmocitário subjacente ao tumor. Além disso, maior expressão de RNAm para IL-6 no CEC foi correlacionada à níveis elevados de corticosterona pós-carcinogênese. Este estudo mostra as primeiras evidências in vivo de que os níveis basais de hormônios do estresse no microambiente do tecido normal podem ser preditivos para a incidência do câncer quimicamente induzido. Além disso, a ação do carcinógeno pode modular os níveis hormonais no microambiente tecidual e estes podem estar associados à progressão do tumor. Em suma, estes dados sugerem que a susceptibilidade ao início e progressão do carcinoma quimicamente induzido pode ser diretamente influenciada por diferenças individuais endócrinas no microambiente pré-carcinogênese.

Introdução: Em crianças e adolescentes, o Transtorno de Humor Bipolar (THB) é associado a danos devastadores no desenvolvimento. O Transtorno de Déficit de Atenção/Hiperatividade (TDAH), caracterizado por sintomas de desatenção, hiperatividade e impulsividade também causa prejuízo funcional significativo. O diagnóstico diferencial entre os dois transtornos é puramente clínico e, até o momento, há poucos estudos avaliando diferenças neurobiológicas. Diversas pesquisas sugerem a participação do Fator Neurotrófico Derivado do Cérebro (BDNF), cujo papel não foi elucidado em crianças e adolescentes com THB e com TDAH. Apesar das altas taxas de comorbidade entre o THB e o TDAH, de uma pior resposta ao tratamento e de um pior funcionamento psicossocial quando da comorbidade, apenas dois estudos avaliaram a resposta ao tratamento especificamente neste grupo de pacientes. Objetivos: O objetivo principal deste trabalho é avançar no entendimento do papel do BDNF na psicopatologia do THB e do TDAH, visando sua diferenciação. O tratamento da comorbidade com estimulantes tambem foi estudado. Métodos: A transmissão do alelo Val66 do BDNF foi avaliada em famílias de crianças e adolescentes com THB e TDAH, assim como o efeito do gene no nível sérico da proteína do BDNF entre os grupos. Foi realizada a comparação dos níveis séricos entre pacientes com THB em comorbidade com TDAH e TDAH isolado. Um estudo clínico cruzado com estimulantes foi realizado em crianças e adolescentes com THB e TDAH em comorbidade que tinham apresentado remissão dos sintomas de humor com o uso de aripiprazol, mas persistência dos sintomas de TDAH. Os sintomas de mania, depressão, desatenção e hiperatividade foram acompanhados ao longo de quatro semanas de tratamento, duas com placebo ou metilfenidato e duas com o tratamento inverso. Resultados: Na investigação da transmissão do gene do BDNF em crianças e adolescentes não foi detectada diferença significativa na transmissão do alelo Val66. Tampouco foi observada diferença significativa nos níveis séricos da proteína do BDNF entre os pacientes com THB em comorbidade com TDAH, quando comparados aos pacientes com TDAH e controles. No estudo cruzado com crianças e adolescentes com THB em comorbidade com TDAH, não houve diferenças entre os grupos com placebo ou estimulantes na resposta ao tratamento nos sintomas de TDAH. Os sintomas de humor mantiveram-se estáveis a despeito do uso de metilfenidato. Conclusões: Os achados quanto ao gene do BDNF não sugerem sua participação na neurobiologia do THB ou no TDAH, ou que devido à herança poligênica característica dos transtornos mentais, sua participação seja pequena. O achado de diferença significativa entre os níveis séricos do BDNF de crianças e adolescentes com THB+TDAH e TDAH indica que esse tema deve ser mais estudado, e, caso seja também encontrado de forma consistente por outros grupos, possa vir a ser utilizado como marcador biológico na diferenciação diagnóstica entre essas condições. No estudo de tratamento da comorbidade entre THB e TDAH, a ausência de resposta ao metilfenidato nos sintomas de TDAH em pacientes que apresentam a comorbidade reforça a evidência de que há pior resposta ao tratamento neste grupo, dado o elevado tamanho de efeito do metilfenidato no tratamento do TDAH em isolado O estudo de fatores biológicos para um melhor entendimento da psicopatologia e conseqüente diferenciação dos transtornos mentais tem extrema relevância porque a identificação destes fatores pode auxiliar na elaboração de tratamentos mais precisos, urgentemente necessários devido às graves conseqüências do THB e do TDAH nas vidas dos pacientes e de suas famílias. A criação de um programa específico para Crianças e Adolescentes com Transtorno Bipolar (ProCAB) e de uma linha de pesquisa com foco na etiologia e tratamento possibilitam uma constante geração de conhecimento nesta área, onde poucos estudos estão disponíveis. / Introduction: Bipolar Disorder (BD) in children and adolescents is associated to devastating developmental deficits. Attention-Deficit/Hyperactivity Disorder (ADHD), characterized by inattention, hyperactivity, and impulsivity, also promotes significant impairment. Differential diagnosis between both conditions is purely clinical – currently, there are scarce investigations on neurobiological differences. Several studies suggest the participation of the Brain-Derived Neurotrophic Factor (BDNF) in these disorders, whose role has not been elucidated in BD and ADHD in children and adolescents. Despite high comorbidity rates between BD and ADHD, worse psychosocial functioning, and worse response to treatment, only two studies addressed treatment response specifically in this group of patients. Objectives: promote advances in understanding the role of BDNF in the psychopathology of BD and ADHD. The treatment of the comorbidity was also studied. Methods: Transmission of the Val66 allele at the BDNF was assessed in children and adolescents with BD and ADHD, as well as the effect of the gene on the serum levels of BDNF protein in both conditions. BDNF serum levels were compared between patients with BD comorbid with ADHD, and ADHD. A crossover clinical trial with stimulants and placebo was performed with children and adolescents preseting BD and comorbid ADHD. Manic, depressive, inatention and hyperactivity symptoms were assessed along a 4-week treatment, 2 weeks in each treatment arm (placebo or stimulants). Results: There was no significant transmission of the Val66 allele at the BDNF gene in children and adolescents with BD or ADHD. A significant difference in BDNF protein serum levels between BD+ADHD when compared to ADHD alone and controls. In the crossover trial with children and adolescents with BD and comorbid ADHD, we did not observe differences between the placebo and stimulant treatment groups in the response of ADHD symptoms. Mood symptoms remained stable despite the use of methylphenidate. Conclusions: our results regarding the BDNF gene do not suggest its participation in the neurobiology of BD or ADHD, or that due to the polygenic characteristic of mental disorders, that this gene confers a only a small risk, undetectable in our sample. The finding of a significant difference in BDNF serum levels between BD comorbid with ADHD, and ADHD alone warrants further investigation, and in case replication studies with larger samples from other groups are positive, BDNF serum levels might be used as a biological marker in the diagnostic difference between these conditions. In the investigation of the treatment of the comorbidity between BD and ADHD, the absence of different responses between placebo and methylphenidate in ADHD symptoms strengthens the evidence that there is a worse response to treatment in this group, given the large effect size of methylphenidate response in the treatment of ADHD alone. The quest for biological markers for a better understanding of the psychopathology and subsequent differentiation of mental disorders is extremely relevant. The identification of these factors may facilitate the creation of more accurate treatment regimens, urgently needed due to the severe developmental consequences of BD and ADHD in the patients’ and families’ lives. In this sense, the creation of a specific outpatient program for children and adolescent BD (ProCAB), a research line with focus on risk factors and treatment, will enable a Constant generation of knowledge in this área, where scarce data is available.

Made available in DSpace on 2015-07-22T20:50:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-30. Added 1 bitstream(s) on 2015-08-11T03:26:08Z : No. of bitstreams: 1 Publico-12662a.pdf: 1757646 bytes, checksum: 6d16ce4a1b202b49620fcd389bf661cb (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:08Z : No. of bitstreams: 2 Publico-12662a.pdf: 1757646 bytes, checksum: 6d16ce4a1b202b49620fcd389bf661cb (MD5) Publico-12662b.pdf: 1556068 bytes, checksum: 9e7692a17342eb563d00b00cb4170335 (MD5) / As evidências científicas que se acumulam ao longo do tempo mostram o impacto positivo do exercício físico para a saúde humana, em especial para a saúde cerebral. Os efeitos como o aumento da atividade neurotrófica do BDNF e do IGF-1, devido ao exercício físico aeróbio, parecem influenciar os neurônios do hipocampo, e estão associados com a melhora do aprendizado e da memória espacial. No entanto, nada se sabe sobre a influência do exercício físico resistido na memória hipocampo-dependente, nem se as vias celulares associadas a essa melhora, pelo exercício físico aeróbio, seriam também ativadas pelo treinamento resistido. Objetivo: Verificar os efeitos dos exercícios físicos aeróbio e resistido na aprendizagem, na memória espacial e nas vias de sinalizações celulares BDNF/ TrKB e do IGF-1/ IGF-1R no hipocampo de ratos. Material e Métodos: ratos Wistar machos adultos foram distribuídos em quatro grupos (controle, CTRL; sham, SHAM; aeróbio, AERO; e resistido, RES), submetidos a oito semanas de treinamento aeróbio (esteira motorizada) ou treinamento resistido (escalada em escada com sobrecarga). Após a intervenção, observou-se que houve, em ambos os grupos AERO e RES, uma melhora da aprendizagem e da memória espacial (hipocampo-dependente), avaliada por meio do labirinto aquático de Morris. Além disto, o grupo AERO ativou mais a via BDNF/ TrKB/ CaMKII do que o RES. No entanto, este grupo ativou mais a via IGF-1/ IGF-1R/ AKT do que o grupo AERO. Apesar de os dois grupos terem aumentado a expressão da sinapsina e da sinaptofisina de forma semelhante. Conclusões: o treinamento aeróbio ou o resistido por oito semanas aumentou, de maneira similar, a aprendizagem e a memória espacial dos ratos. Embora os mecanismos moleculares pelo qual isso ocorreu, até certo ponto tenham sido divergentes. Isso porque, o exercício físico aeróbio ativou a via BDNF/TrKB/CaMKII e, o resistido a via IGF-1/IGF-1R/AKT, embora ambos, de maneira similar, tenham aumentado, no hipocampo, a expressão da sinapsina e da sinaptofisina. / A growing body of scientific evidence indicates that exercise has a positive impact on human health and on neurological health in particular. Effects such as increased BDNF and IGF-1 neurotrophic activity are induced by aerobic exercise and appear to influence hippocampal neurons, leading to improved spatial learning and memory. However, nothing is known about the effect of resistance exercise on hippocampus-dependent memory or whether the cellular pathways associated with aerobic exercise are also activated by resistance training. Objective: we therefore tested whether spatial learning and memory in rats is similarly enhanced by aerobic or resistance exercise and whether the cellular signals involved are similar, focusing on the BDNF/ TrKB and IGF-1/ IGF-1R pathways. Material and Methods: Adult male Wistar rats underwent eight weeks of aerobic training on a treadmill (AERO group) or resistance training on a vertical ladder (RES group); control and sham groups were also included. After the training period, both the AERO and RES groups showed improved learning and spatial memory. In addition, the BDNF/TrkB/CaMKII pathway had a higher activity in the AERO group than in the RES group. In contrast, the RES group showed greater activation of the IGF-1/IGF-1R/AKT pathway. Moreover, the two exercise groups had similar increases in synapsin and synaptophysin expression. Conclusions: We therefore conclude that, in rats, both aerobic and resistance training for eight weeks increases learning and spatial memory in a similar manner. However, the two forms of exercise seem to employ at least partially divergent mechanisms. Specifically, aerobic exercise modulates neuroplasticity selectively via the BDNF/TrkB pathway by activating CaMKII and stimulating the synthesis of synapsin and synaptophysin. In contrast, resistance training appears to increase synapsin and synaptophysin expression via the IGF-1/IGF-1R pathway. / TEDE / BV UNIFESP: Teses e dissertações

BDNF/TrkB são descritos em diversas neoplasias onde iniciam sinais mitogênicos, facilitam o crescimento tumoral, previnem apoptose e regulam angiogênese e metástase. Outros fatores de crescimento também são importantes para tumorigênese, como GRP/GRPR e EGF/EGFR. O objetivo geral deste trabalho foi investigar o papel de BDNF/TrkB em câncer colorretal avaliando possíveis interações com GRPR e EGFR. Verificamos que BDNF e seu receptor, TrkB, estão presentes em amostras de pacientes com câncer colorretal esporádico, e os níveis de BDNF encontram-se mais elevados no tecido neoplásico que no tecido adjacente ao tumor. O tratamento com RC- 3095, um antagonista de GRPR, na linhagem celular de câncer colorretal humana, HT-29, causa diminuição nos níveis de NGF secretados pelas células e aumento de BDNF em relação ao controle não tratado. RC-3095 inibe a proliferação e viabilidade celular das linhagens HT-29 (EGFR positiva) e SW-620 (EGFR negativa), embora apenas em HT-29 ocorra um aumento significativo na expressão de mRNA de BDNF. Por isso, um anticorpo monoclonal anti-EGFR, cetuximabe, foi combinado a RC-3095, nas células HT-29, sendo capaz de prevenir tal aumento, sugerindo que este efeito seja mediado por EGFR. Os tratamentos com um inibidor de Trks, K252a (1000 nM) ou com cetuximabe (10 nM) também inibem a proliferação celular. Entretanto, a combinação de BDNF a cetuximabe previne este efeito, enquanto que a combinação de doses não efetivas de K252a (10 nM) à cetuximabe (1 nM) inibe a proliferação celular de HT- 29. Além disso, cetuximabe também causa aumento na expressão de mRNA de TrkB e BDNF, após 600 minutos de tratamento. Nossos resultados sugerem que a inibição da proliferação celular in vitro ou do crescimento tumoral in vivo devem acontecer através do bloqueio combinado entre GRPR e TrkB em células de câncer colorretal EGFR positivas, e que BDNF também esteja envolvido em mecanismos de resistência a fármacos. Por isso, o bloqueio de BDNF / TrkB pode emergir como potencial alvo antitumoral. / BDNF / TrkB are described in various cancers where they participate in tumor growth, apoptosis, angiogenesis and metastasis. Furthermore, other growth factors are also important to tumorigenesis as GRP/GRPR and EGF/EGFR. Therefore, the aim of this study was to investigate the role of BDNF/TrkB in colorectal cancer evaluating the interactions with GRPR and EGFR. We found that BDNF and its receptor, TrkB, are present in samples from patients diagnosed with sporadic colorectal cancer, and BDNF levels were higher in tumor tissue compared to adjacent tumor tissue. Treatment with RC-3095, GRPR antagonist, in human colorectal cancer cell line, HT-29 caused a decrease in NGF levels secreted by cells, and generated increase of BDNF when compared to untreated control. RC-3095 inhibited the proliferation and cell viability in HT-29 (EGFR positive) and SW-620 (EGFR negative), but only HT-29 cells showed a significant increase in BDNF mRNA expression. Therefore, a monoclonal anti-EGFR antibody, cetuximab was combined with RC-3095 in HT-29 cells, and was able to prevent such an increase, suggesting that this effect is mediated by EGFR. The treatment with a Trk inhibitor, K252a (1000 nM) or cetuximab (10 nM), inhibited cell proliferation. However, the combination of BDNF with cetuximab prevented this effect, whereas the combination of ineffective doses of K252a (10 nM) with cetuximab (1 nM) still inhibited cell proliferation of HT-29. Furthermore, cetuximab also caused an increase in BDNF and TrkB mRNA expression, 600 minutes after treatment. In summary, our results suggest that inhibition of cell proliferation in vitro or tumor growth in vivo must occur between the combination of GRPR and TrkB in EGFR positive colorectal cancer cells, and that BDNF is also involved in drug resistance mechanisms. Therefore, blockage of BDNF / TrkB may emerge as potential antitumor target.

BDNF/TrkB são descritos em diversas neoplasias onde iniciam sinais mitogênicos, facilitam o crescimento tumoral, previnem apoptose e regulam angiogênese e metástase. Outros fatores de crescimento também são importantes para tumorigênese, como GRP/GRPR e EGF/EGFR. O objetivo geral deste trabalho foi investigar o papel de BDNF/TrkB em câncer colorretal avaliando possíveis interações com GRPR e EGFR. Verificamos que BDNF e seu receptor, TrkB, estão presentes em amostras de pacientes com câncer colorretal esporádico, e os níveis de BDNF encontram-se mais elevados no tecido neoplásico que no tecido adjacente ao tumor. O tratamento com RC- 3095, um antagonista de GRPR, na linhagem celular de câncer colorretal humana, HT-29, causa diminuição nos níveis de NGF secretados pelas células e aumento de BDNF em relação ao controle não tratado. RC-3095 inibe a proliferação e viabilidade celular das linhagens HT-29 (EGFR positiva) e SW-620 (EGFR negativa), embora apenas em HT-29 ocorra um aumento significativo na expressão de mRNA de BDNF. Por isso, um anticorpo monoclonal anti-EGFR, cetuximabe, foi combinado a RC-3095, nas células HT-29, sendo capaz de prevenir tal aumento, sugerindo que este efeito seja mediado por EGFR. Os tratamentos com um inibidor de Trks, K252a (1000 nM) ou com cetuximabe (10 nM) também inibem a proliferação celular. Entretanto, a combinação de BDNF a cetuximabe previne este efeito, enquanto que a combinação de doses não efetivas de K252a (10 nM) à cetuximabe (1 nM) inibe a proliferação celular de HT- 29. Além disso, cetuximabe também causa aumento na expressão de mRNA de TrkB e BDNF, após 600 minutos de tratamento. Nossos resultados sugerem que a inibição da proliferação celular in vitro ou do crescimento tumoral in vivo devem acontecer através do bloqueio combinado entre GRPR e TrkB em células de câncer colorretal EGFR positivas, e que BDNF também esteja envolvido em mecanismos de resistência a fármacos. Por isso, o bloqueio de BDNF / TrkB pode emergir como potencial alvo antitumoral. / BDNF / TrkB are described in various cancers where they participate in tumor growth, apoptosis, angiogenesis and metastasis. Furthermore, other growth factors are also important to tumorigenesis as GRP/GRPR and EGF/EGFR. Therefore, the aim of this study was to investigate the role of BDNF/TrkB in colorectal cancer evaluating the interactions with GRPR and EGFR. We found that BDNF and its receptor, TrkB, are present in samples from patients diagnosed with sporadic colorectal cancer, and BDNF levels were higher in tumor tissue compared to adjacent tumor tissue. Treatment with RC-3095, GRPR antagonist, in human colorectal cancer cell line, HT-29 caused a decrease in NGF levels secreted by cells, and generated increase of BDNF when compared to untreated control. RC-3095 inhibited the proliferation and cell viability in HT-29 (EGFR positive) and SW-620 (EGFR negative), but only HT-29 cells showed a significant increase in BDNF mRNA expression. Therefore, a monoclonal anti-EGFR antibody, cetuximab was combined with RC-3095 in HT-29 cells, and was able to prevent such an increase, suggesting that this effect is mediated by EGFR. The treatment with a Trk inhibitor, K252a (1000 nM) or cetuximab (10 nM), inhibited cell proliferation. However, the combination of BDNF with cetuximab prevented this effect, whereas the combination of ineffective doses of K252a (10 nM) with cetuximab (1 nM) still inhibited cell proliferation of HT-29. Furthermore, cetuximab also caused an increase in BDNF and TrkB mRNA expression, 600 minutes after treatment. In summary, our results suggest that inhibition of cell proliferation in vitro or tumor growth in vivo must occur between the combination of GRPR and TrkB in EGFR positive colorectal cancer cells, and that BDNF is also involved in drug resistance mechanisms. Therefore, blockage of BDNF / TrkB may emerge as potential antitumor target.

Introdução: Em crianças e adolescentes, o Transtorno de Humor Bipolar (THB) é associado a danos devastadores no desenvolvimento. O Transtorno de Déficit de Atenção/Hiperatividade (TDAH), caracterizado por sintomas de desatenção, hiperatividade e impulsividade também causa prejuízo funcional significativo. O diagnóstico diferencial entre os dois transtornos é puramente clínico e, até o momento, há poucos estudos avaliando diferenças neurobiológicas. Diversas pesquisas sugerem a participação do Fator Neurotrófico Derivado do Cérebro (BDNF), cujo papel não foi elucidado em crianças e adolescentes com THB e com TDAH. Apesar das altas taxas de comorbidade entre o THB e o TDAH, de uma pior resposta ao tratamento e de um pior funcionamento psicossocial quando da comorbidade, apenas dois estudos avaliaram a resposta ao tratamento especificamente neste grupo de pacientes. Objetivos: O objetivo principal deste trabalho é avançar no entendimento do papel do BDNF na psicopatologia do THB e do TDAH, visando sua diferenciação. O tratamento da comorbidade com estimulantes tambem foi estudado. Métodos: A transmissão do alelo Val66 do BDNF foi avaliada em famílias de crianças e adolescentes com THB e TDAH, assim como o efeito do gene no nível sérico da proteína do BDNF entre os grupos. Foi realizada a comparação dos níveis séricos entre pacientes com THB em comorbidade com TDAH e TDAH isolado. Um estudo clínico cruzado com estimulantes foi realizado em crianças e adolescentes com THB e TDAH em comorbidade que tinham apresentado remissão dos sintomas de humor com o uso de aripiprazol, mas persistência dos sintomas de TDAH. Os sintomas de mania, depressão, desatenção e hiperatividade foram acompanhados ao longo de quatro semanas de tratamento, duas com placebo ou metilfenidato e duas com o tratamento inverso. Resultados: Na investigação da transmissão do gene do BDNF em crianças e adolescentes não foi detectada diferença significativa na transmissão do alelo Val66. Tampouco foi observada diferença significativa nos níveis séricos da proteína do BDNF entre os pacientes com THB em comorbidade com TDAH, quando comparados aos pacientes com TDAH e controles. No estudo cruzado com crianças e adolescentes com THB em comorbidade com TDAH, não houve diferenças entre os grupos com placebo ou estimulantes na resposta ao tratamento nos sintomas de TDAH. Os sintomas de humor mantiveram-se estáveis a despeito do uso de metilfenidato. Conclusões: Os achados quanto ao gene do BDNF não sugerem sua participação na neurobiologia do THB ou no TDAH, ou que devido à herança poligênica característica dos transtornos mentais, sua participação seja pequena. O achado de diferença significativa entre os níveis séricos do BDNF de crianças e adolescentes com THB+TDAH e TDAH indica que esse tema deve ser mais estudado, e, caso seja também encontrado de forma consistente por outros grupos, possa vir a ser utilizado como marcador biológico na diferenciação diagnóstica entre essas condições. No estudo de tratamento da comorbidade entre THB e TDAH, a ausência de resposta ao metilfenidato nos sintomas de TDAH em pacientes que apresentam a comorbidade reforça a evidência de que há pior resposta ao tratamento neste grupo, dado o elevado tamanho de efeito do metilfenidato no tratamento do TDAH em isolado O estudo de fatores biológicos para um melhor entendimento da psicopatologia e conseqüente diferenciação dos transtornos mentais tem extrema relevância porque a identificação destes fatores pode auxiliar na elaboração de tratamentos mais precisos, urgentemente necessários devido às graves conseqüências do THB e do TDAH nas vidas dos pacientes e de suas famílias. A criação de um programa específico para Crianças e Adolescentes com Transtorno Bipolar (ProCAB) e de uma linha de pesquisa com foco na etiologia e tratamento possibilitam uma constante geração de conhecimento nesta área, onde poucos estudos estão disponíveis. / Introduction: Bipolar Disorder (BD) in children and adolescents is associated to devastating developmental deficits. Attention-Deficit/Hyperactivity Disorder (ADHD), characterized by inattention, hyperactivity, and impulsivity, also promotes significant impairment. Differential diagnosis between both conditions is purely clinical – currently, there are scarce investigations on neurobiological differences. Several studies suggest the participation of the Brain-Derived Neurotrophic Factor (BDNF) in these disorders, whose role has not been elucidated in BD and ADHD in children and adolescents. Despite high comorbidity rates between BD and ADHD, worse psychosocial functioning, and worse response to treatment, only two studies addressed treatment response specifically in this group of patients. Objectives: promote advances in understanding the role of BDNF in the psychopathology of BD and ADHD. The treatment of the comorbidity was also studied. Methods: Transmission of the Val66 allele at the BDNF was assessed in children and adolescents with BD and ADHD, as well as the effect of the gene on the serum levels of BDNF protein in both conditions. BDNF serum levels were compared between patients with BD comorbid with ADHD, and ADHD. A crossover clinical trial with stimulants and placebo was performed with children and adolescents preseting BD and comorbid ADHD. Manic, depressive, inatention and hyperactivity symptoms were assessed along a 4-week treatment, 2 weeks in each treatment arm (placebo or stimulants). Results: There was no significant transmission of the Val66 allele at the BDNF gene in children and adolescents with BD or ADHD. A significant difference in BDNF protein serum levels between BD+ADHD when compared to ADHD alone and controls. In the crossover trial with children and adolescents with BD and comorbid ADHD, we did not observe differences between the placebo and stimulant treatment groups in the response of ADHD symptoms. Mood symptoms remained stable despite the use of methylphenidate. Conclusions: our results regarding the BDNF gene do not suggest its participation in the neurobiology of BD or ADHD, or that due to the polygenic characteristic of mental disorders, that this gene confers a only a small risk, undetectable in our sample. The finding of a significant difference in BDNF serum levels between BD comorbid with ADHD, and ADHD alone warrants further investigation, and in case replication studies with larger samples from other groups are positive, BDNF serum levels might be used as a biological marker in the diagnostic difference between these conditions. In the investigation of the treatment of the comorbidity between BD and ADHD, the absence of different responses between placebo and methylphenidate in ADHD symptoms strengthens the evidence that there is a worse response to treatment in this group, given the large effect size of methylphenidate response in the treatment of ADHD alone. The quest for biological markers for a better understanding of the psychopathology and subsequent differentiation of mental disorders is extremely relevant. The identification of these factors may facilitate the creation of more accurate treatment regimens, urgently needed due to the severe developmental consequences of BD and ADHD in the patients’ and families’ lives. In this sense, the creation of a specific outpatient program for children and adolescent BD (ProCAB), a research line with focus on risk factors and treatment, will enable a Constant generation of knowledge in this área, where scarce data is available.

Einleitung: Bei der Dystonie handelt es sich um eine Erkrankung des zentralen Nervensystems. Sie ist charakterisiert durch ungewollte, dauerhafte oder wiederkehrende Muskelkontraktionen, die zu abnormalen Bewegungsabläufen und Haltungen führen. Sie ist die dritthäufigste Bewe-gungsstörung beim Menschen. Bisherige Befunde beim Menschen und Untersuchungen an Tier-modellen weisen u.a. auf eine besondere Bedeutung der Basalganglien-Thalamus-Schleife hin, die an der Kontrolle von willkürlichen und unwillkürlichen Bewegungen beteiligt ist. So konnten bei unterschiedlichen Tiermodellen Veränderungen im Striatum (STR), der Eingangsstruktur der Basalganglien, nachgewiesen werden. Beim dtsz Hamster, einem gut etablierten Tiermodell für die paroxysmale Dystonie, konnte neben vielen striatalen Veränderungen eine Reduktion der GABAergen Interneurone (IN), wie Parvalbumin-positive (PV+) IN, zum Zeitpunkt der maximalen Ausprägung der Dystonie gezeigt werden. Ziele der Untersuchung: Die Gründe für den Mangel an striatalen GABAergen IN bei der dtsz Hamstermutante sollten weiter untersucht werden, indem der Frage nachzugehen war, ob beim dtsz Hamster eine Migrations- oder Ausreifungsstörung der IN vorliegt. Dazu wurde das Homöodomänprotein Nkx 2.1, als Marker für aus dem medialen Ganglienhügel eingewanderte IN, im STR der dtsz Hamstermutante untersucht. Die Expression des Brain-derived neurotrophic factors (BDNF), des Kalium-Chlorid-Kotransporters 2 (KCC2) und die zytosolische Carboanhydrase vom Isotyp 7 (CAH7) wurden als Indikatoren für die Ausreifung von GABAergen IN herangezogen. Tiere, Material und Methoden: Die Untersuchungen wurden vergleichend an dtsz Hamstern und Kontrollhamstern durchgeführt. Beim dtsz Hamster zeigt die Dystonie einen altersabhängigen Verlauf (Beginn: ca. 16. Lebenstag (LT); Maximum: 30.-42. LT; Remission: 70. LT). Deshalb wurden als Untersuchungszeitpunkte der 18. LT und der 33. LT gewählt. Um die Migration der striatalen IN zu untersuchen, wurde im STR bei 33 Tage alten Hamsterns die Dichte der immun-histochemisch markierten Nkx 2.1-positiven Zellen stereologisch ermittelt. Der mRNA-Gehalt wurde relativ mittels „quantitativer Echtzeit-PCR“ (qPCR) bestimmt. Zusätzlich wurde die mRNA-Expression von Nkx 2.1 bei 18 Tage alten Tieren untersucht. Von KCC2 und CAH7 wurde die mRNA mittels qPCR bei 18 und 33 Tage alten Hamstern im STR untersucht. Die Expression von BDNF wurde mittels ELISA-System im Kortex (Cx), STR und im restlichen Gehirngewebe („R“) bei 33 und 18 Tage alten Tieren bestimmt. Der BDNF-mRNA Gehalt wurde im Cx (18. und 33. LT) und im STR (33. LT) untersucht. Des Weiteren sollte BDNF bei 33 Tage alten Hamstern mittels immunhistochemischer Markierung im Cx und STR untersucht werden. Die Untersuchung von BDNF im Cx ist deshalb wichtig, weil BDNF vom Cx in das STR trans-portiert wird. Zusätzlich wurde Parvalbumin (PV) zusammen mit Nkx 2.1 immunhistochemisch markiert und die mRNA-Expression von PV bei 18 und 33 Tage alten Tieren bestimmt. Ergebnisse: Für Nkx 2.1 konnte kein Unterschied in der Zelldichte zwischen dtsz- und Kontroll-hamstern gefunden werden. Ebenfalls gab es weder bei 18 noch bei 33 Tage alten Tieren einen Unterschied in der Nkx 2.1-mRNA-Expression. Unterschiede in der mRNA-Expression von KCC2 und CAH7 im STR (18. und 33. LT) lagen auch nicht vor. Die Expression der PV-mRNA im STR bei 33 Tage alten Tieren war jedoch erwartungsgemäß vermindert. Auf mRNA-Ebene konnte im Cx für BDNF kein Unterschied zwischen dtsz- und Kontrolltiergruppe gefunden wer-den. Bei beiden Tiergruppen wurde mittels ELISA im STR mehr BDNF nachgewiesen als im Cx und im R (18. und 33. LT) nachweisbar. Entgegen der Hypothese war nach Analyse der Daten mittels Zwei-Wege ANOVA eine geringe Erhöhung der BDNF-Expression im Cx und STR bei 33 Tage alten dtsz Hamstern nachweisbar. Dies lag daran, dass die BDNF-Expression nur bei den Kontrolltieren am 33. LT im Vergleich zum 18. LT herunterreguliert war. Die Ergebnisse der BDNF-Immunhistologie waren in Hinblick auf die Spezifität zweifelhaft. Schlussfolgerung: Die Nkx 2.1 Daten lassen auf eine ungestörte Migration striataler IN bei der dtsz Mutante schließen. Wahrscheinlich ist eine Ausreifungsstörung für den Mangel an GABAer-gen IN verantwortlich. Die Ergebnisse von KCC2 und CAH7 zeigen, dass keine generelle Ausreifungsstörung von GABAergen Neuronen vorliegt, wobei dies für kleinere Subpopulationen nicht ausgeschlossen werden kann. Entgegen der Arbeitshypothese konnte keine Verringerung sondern eine leichte Erhöhung von BDNF zum 33. LT bei der dtsz Hamstermutante festgestellt werden. Eine mögliche Erklärung könnte sein, dass BDNF auf Grund der verzögert einsetzenden Entwicklung der IN nicht herunterreguliert wird. Die Gründe für diese Erhöhung wie auch weitere Marker für die neuronale Ausreifung werden durch weiterführende Studien untersucht.

This research delves into idiopathic autism spectrum disorder (ASD), investigating the role of TrkB signaling pathways and BDNF regulation in the cortex. Additionally, it explores offering insights into maternal influences on mouse models. / Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by challenges in social interactions and repetitive behaviors. Prevalence of ASD is estimated to be 1 in 54 globally and is rising recently in many countries including Canada. ASD affects individuals differently, making diagnosis challenging. At present, no molecular diagnosis of ASD is available. Further, available medications only manage some symptoms of the disease and have adverse side effects in children. Therefore, there is a need for accurate molecular diagnostic tools to aid in molecular detection and treatment of ASD. To this end, a better understanding of the underlying molecular mechanisms that link ASD etiology to ASD-related behavior is crucial. While genetic factors contribute to syndromic ASD, most cases of ASD are idiopathic with unknown causes, influenced by a combination of epigenetic and environmental factors. TrkB and its downstream signaling pathways, such as Akt and Erk, are hyper-activated in syndromic ASD and hypo-activated in idiopathic cases. Therefore, drugs like rapamycin that inhibit the mTOR pathway downstream of TrkB are beneficial for syndromic ASD but not idiopathic cases. Additionally, insulin-like growth factor 1 (IGF-1), which mitigates ASD-related synaptic disruptions via Akt and Erk signaling, shows unchanged mRNA and protein levels along with its receptor in the idiopathic ASD fusiform gyrus. In ASD with either genetic or epigenetic/environmental causes, disruptions in synaptic connectivity are observed. Synaptic function is regulated by signaling pathways involving brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), as well as their downstream signaling cascades such as MAPK and Akt. The existing literature suggests that there is an association between BDNF and TrkB signaling pathways and ASD. However, a serious gap in knowledge about the precise molecular role of TrkB in ASD pathology is that our current understanding is correlational in nature and based on observational studies that lack causal experiments. This underscores the importance of further research to understand the causative role of TrkB and its related molecular events in idiopathic ASD. The present work aims to provide a deeper understanding about the causative role of molecular mechanisms underlying TrkB signaling in ASD. ASD mouse models exhibit behaviors and molecular features resembling those observed in human ASD. Therefore, these mouse models are helpful tools for studying ASD. However, understudied physiological confounding factors, such as maternal age and parity, can introduce biases and add to data variability, thus negatively impacting the reproducibility and translational value of ASD mouse models. To achieve a reliable mouse model of ASD, we conducted our first study that examines the impact of maternal age and parity on pregnancy complications, neurodevelopment, and social behavior in mice. Results demonstrate that older maternal age and prior motherhood interact to ensure a normal, steady developmental rate and provide protective effects against anxiety, social impairment, and olfactory deficits. Given the current lack of clarity regarding the causative impact of TrkB on ASD pathology, our subsequent investigation sought to establish a causal relationship between TrkB signaling and ASD. We used the TrkB agonist, LM22A-4 treatment in a validated ASD mouse model. Our results demonstrate that treatment with LM22A-4 effectively rescues the core symptoms associated with ASD (social impairment and repetitive behavior). These findings indicate that impaired TrkB signaling is responsible for ASD-like behavior of valproic acid (VPA)-exposed mice. However, unlike TrkB-related molecular events occurring in the fusiform gyrus of idiopathic ASD, TrkB isoform protein levels, BDNF species, Akt, and Erk total protein levels and activation remained unchanged in VPA-exposed cortices compared to healthy control mice. Since our VPA mouse model does not replicate human idiopathic ASD, our study cannot draw a conclusion on how disruptions in these signaling pathways may contribute to the development and manifestation of ASD symptoms. Cortex is responsible for various aspects of social behavior that are impaired in ASD. However, regulatory mechanisms that are involved in ASD upstream of cortical TrkB and BDNF are not well known. BDNF expression is highly cell-and tissue-specific and is regulated by different sets of transcription factors in specific tissues. While NURR1, the BDNF regulator in midbrain neurons, is associated with ASD pathology, its specific role in regulation of cortical BDNF is not yet well-established. Our third study aimed to understand the role of NURR1 in regulating BDNF specifically in the cortex. We showed that in resting and depolarized neurons, when NURR1 is knocked down, BDNF mRNA levels remained unchanged, suggesting that NURR1 does not regulate BDNF in cortical neurons and highlighting the tissue-specificity of BDNF regulation. In summary, we address the understudied effects of maternal factors on mouse models, which enhances the reliability of ASD research. Further, our studies significantly enhance the understanding of ASD by elucidating the role of TrkB and its downstream signaling pathways in the behavioral aspects of the disorder. We also contribute to the knowledge of BDNF regulation in the cortex, a brain tissue with crucial roles in various aspects of social behavior. In a forward-looking approach, the results of our studies provide valuable insights into mouse modeling of idiopathic ASD and the potential role of TrkB in ASD behavioral symptoms. / Thesis / Candidate in Philosophy / Autism spectrum disorder (ASD) is a condition that is accompanied by challenges in social interaction and repetitive behaviors. ASD is a complicated condition because we do not fully understand all the details of how it works in the body. Studying ASD is important as it is the most challenging condition in children and it is becoming more common, especially in the last two decades. While scientists are developing molecular tools to improve ASD diagnosis and understand its biology, these tools are not widely used in clinics for ASD diagnosis yet. Also, the approved medications available can only help with managing some of the behavioral symptoms like self-harming behavior. Despite the pressing need to find a solution, our recent advancements have not yet brought us closer to a cure for ASD, mainly because of the complexity of the disorder. Therefore, identifying the specific ASD-related mechanisms at the molecular level that contribute to ASD-related behaviors is crucial for gaining a deeper understanding of the disease. In ASD, there are problems with how brain cells communicate with each other. This communication is controlled by certain molecules in the brain, such as brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), along with other molecules. There is evidence suggesting a link between these molecules and ASD, but we have not fully understood their precise roles because most of the current knowledge is based on observations and correlations, rather than on establishing cause-and-effect relationships. To bridge this gap, our research focused on understanding TrkB's role in ASD. We required reliable mouse models. Since we aimed to induce ASD-like behaviors in mice using an ASD-causing chemical, it was crucial to ensure they were healthy beforehand. We needed to confirm that any social deficits or repetitive behaviors were not due to other factors, such as adverse infancy experiences or impaired interactions between mother and infant. We discovered that sexually mature dams aged between 3 to 6 months, with a history of previous pregnancies and motherhood, give birth to healthier litters. These litters can serve as a more dependable source for our animal behavioral studies. Many cases of ASD in humans are caused by non-genetic factors such as environmental influences like pesticides, air pollution, and the use of certain drugs during pregnancy. In cases of human ASD triggered by non-genetic factors, there is an increase in proBDNF, the precursor of BDNF. However, this proBDNF does not efficiently convert to BDNF. With insufficient BDNF and TrkB receptors, molecules like Akt (protein kinase B, also PKB) and Erk (Extracellular Signal-Regulated Kinase), which are crucial for neuron communication, are also less active downstream. This imbalance disrupts neuron connections, leading to ASD behaviors. In our research, the ASD-causing chemical which we used is valproic acid. It is originally an anti-seizure medication. When pregnant women took valproic acid, the chance of their child having ASD increased. Scientists used this information to inject pregnant mice with valproic acid, and as a result, all the offspring showed ASD-like behaviors. We anticipated that by isolating the brains of these offspring and measuring protein levels of BDNF, TrkB, Akt, and Erk, we would observe a similar pattern to that seen in humans with non-genetic ASD cases. We focused on studying the cortex, a region of the brain responsible for regulating social behaviors in both mice and humans. Since ASD is associated with challenges in social behaviors, we isolated the cortex from mouse brains to analyze protein levels. A chemical known as LM22A-4 with a structure resembling BDNF can bind to TrkB and activate it. We expected that the offspring of pregnant dams injected with valproic acid, which led to reduced TrkB axis activation in their brains, would show improvement in ASD behavior. This anticipation stems from the understanding that LM22A-4 activates the TrkB axis, thus compensating for its reduction, which is thought to be causing ASD-like behaviors. The offspring of mothers injected with valproic acid exhibited ASD-like behaviors, unlike the control mice. Control mice were offspring of pregnant dams injected with a solution containing only the substances used to dissolve valproic acid, typically water and salt (saline). Mice prenatally exposed to valproic acid (VPA) exhibited ASD-like behaviors, but treatment with LM22A-4 helped alleviate these behaviors, promoting more typical behavior patterns. LM22A-4, by activating TrkB receptors, helped to protect the brain from harm caused by exposure to valproic acid before birth. This could mean that valproic acid-induced changes in TrkB-related molecular mechanisms are involved in social behavior difficulties and increased repetitive behaviors seen in autism. Nevertheless, the levels of TrkB, BDNF, proBDNF, Akt, and Erk in the cortex of offspring from mothers injected with valproic acid were like those in the offspring from mothers injected with the saline solution. Therefore, the BDNF and TrkB signaling pathways remained unchanged in the cortex of our valproic acid model in this study, and they differ from those observed in human idiopathic ASD. We also speculated that a protein, called NURR1 acting upstream of BDNF and TrkB might be involved in the process. NURR1 acts as a regulatory protein that binds to the BDNF, increasing the production of copies from the BDNF. We also used a small RNA that targets a specific region in the Nurr1 and inhibits its protein production We anticipated a reduction in Nurr1 levels. As NURR1 acts as an upregulator of BDNF, lower levels of Nurr1 would result in decreased BDNF production. Activating NURR1 resulted in increased BDNF mRNA levels. However, when NURR1 was reduced, BDNF mRNA levels remained unaffected. This led us to conclude that if NURR1 levels decrease, other proteins may step in to maintain BDNF mRNA levels. Therefore, in the cortex, unlike in some other brain regions, the presence of NURR1 is not essential for regulating Bdnf. In summary, before inducing ASD-like behavior in mice using valproic acid, it is crucial to ensure the health of the mice. We used sexually mature mothers with prior pregnancy experience to provide a healthy baseline. We showed valproic acid induced ASD-like behaviors in mice offspring. We also observed that LM22A-4 treatment alleviated ASD-like behaviors of offspring. In our study, we demonstrated that the levels of BDNF, TrkB, Erk, and Akt proteins in the cortex of mice exposed to valproic acid were not affected. For this reason, our mouse model does not resemble human non-genetic ASD. Finally, NURR1's role in BDNF regulation varies by brain region. Lowering NURR1 did not affect BDNF mRNA levels, suggesting compensatory mechanisms. Our findings suggest new directions for further research to better understand the roles of TrkB and BDNF in non-genetic ASD. Overall, this study provides valuable knowledge that can contribute to advancing our understanding of idiopathic ASD-related molecular mechanisms.

Le glaucome est la deuxième cause de cécité irréversible dans le monde. La perte de vision qui se produit lors du glaucome s’explique par une dégénérescence du nerf optique et une mort progressive et sélective des cellules ganglionnaires de la rétine (CRG). L'hypertension oculaire est un facteur de risque majeur dans le glaucome, mais des défauts du champ visuel continuent à se développer chez un contingent de patients malgré l'administration de médicaments qui abaissent la pression intraoculaire (PIO). Par conséquent, bien que la PIO représente le seul facteur de risque modifiable dans le développement du glaucome, son contrôle ne suffit pas à protéger les CRGs et préserver la fonction visuelle chez de nombreux patients. Dans ce contexte, j'ai avancé l'hypothèse centrale voulant que les stratégies de traitement du glaucome visant à promouvoir la protection structurale et fonctionnelle des CRGs doivent agir sur les mécanismes moléculaires qui conduisent à la mort des ces neurones. Dans la première partie de ma thèse, j'ai caractérisé l'effet neuroprotecteur de la galantamine, un inhibiteur de l'acétylcholinestérase qui est utilisé cliniquement dans le traitement de la maladie d'Alzheimer. Cette étude s’est basée sur l'hypothèse que la galantamine, en modulant l'activité du récepteur de l'acétylcholine, puisse améliorer la survie des CRGs lors du glaucome. Nous avons utilisé un modèle expérimental bien caractérisé d'hypertension oculaire induite par l’administration d'une solution saline hypertonique dans une veine épisclérale de rats Brown Norway. Les résultats de cette étude (Almasieh et al. Cell Death and Disease, 2010) ont démontré que l'administration quotidienne de galantamine améliore de manière significative la survie des corps cellulaires et des axones CRGs. La protection structurelle des CRGs s’accompagne d’une préservation remarquable de la fonction visuelle, évaluée par l'enregistrement des potentiels évoqués visuels (PEV) dans le collicule supérieur, la cible principale des CRGs chez le rongeur. Une autre constatation intéressante de cette étude est la perte substantielle de capillaires rétiniens et la réduction du débit sanguin associé à la perte des CRGs dans le glaucome expérimental. Il est très intéressant que la galantamine ait également favorisé la protection de la microvascularisation et amélioré le débit sanguin rétinien des animaux glaucomateux (Almasieh et al. en préparation). J'ai notamment démontré que les neuro-et vasoprotections médiées par la galantamine se produisent par iv l'activation des récepteurs muscariniques de l'acétylcholine. Dans la deuxième partie de ma thèse, j'ai étudié le rôle du stress oxydatif ainsi que l'utilisation de composés réducteurs pour tester l'hypothèse que le blocage d'une augmentation de superoxyde puisse retarder la mort des CRG lors du glaucome expérimental. J'ai profité d'un composé novateur, un antioxydant à base de phosphineborane (PB1), pour tester sur son effet neuroprotecteur et examiner son mécanisme d'action dans le glaucome expérimental. Les données démontrent que l'administration intraoculaire de PB1 entraîne une protection significative des corps cellulaire et axones des CRGs. Les voies moléculaires conduisant à la survie neuronale médiée par PB1 ont été explorées en déterminant la cascade de signalisation apoptotique en cause. Les résultats démontrent que la survie des CRGs médiée par PB1 ne dépend pas d’une inhibition de signalisation de protéines kinases activées par le stress, y compris ASK1, JNK ou p38. Par contre, PB1 induit une augmentation marquée des niveaux rétiniens de BDNF et une activation en aval de la voie de survie des ERK1 / 2 (Almasieh et al. Journal of Neurochemistry, 2011). En conclusion, les résultats présentés dans cette thèse contribuent à une meilleure compréhension des mécanismes pathologiques qui conduisent à la perte de CRGs dans le glaucome et pourraient fournir des pistes pour la conception de nouvelles stratégies neuroprotectrices et vasoprotectrices pour le traitement et la gestion de cette maladie. / Glaucoma is the second cause of irreversible blindness worldwide. Loss of vision in glaucoma is accompanied by progressive optic nerve degeneration and selective loss of retinal ganglion cells (RGCs). Ocular hypertension is a major risk factor in glaucoma, but visual field defects continue to progress in a large group of patients despite the use of drugs that lower intraocular pressure (IOP). Therefore, although IOP is the sole modifiable risk factor in the development of glaucoma, its regulation is not sufficient to protect RGCs and preserve visual function in many affected patients. To address this issue, I put forward the central hypothesis that effective therapeutic strategies for glaucoma must interfere with molecular mechanisms that lead to RGC death to successfully promote structural and functional protection of these neurons. In the first part of my thesis, I characterized the neuroprotective effect of galantamine, an acetylcholinesterase inhibitor that is clinically used for the treatment of Alzheimer’s disease. The specific hypothesis of this study was that galantamine, by modulating acetylcholine receptor activity, can improve the survival of injured RGCs in glaucoma. A well characterized experimental model of ocular hypertension induced by administration of a hypertonic saline into an episcleral vein of Brown Norway rats was used. The results of this study (Almasieh et al. Cell Death and Disease, 2010) demonstrated that daily administration of galantamine significantly improved the survival of RGC soma and axons in this model. Structural protection of RGCs correlated with substantial preservation of visual function, assessed by recording visual evoked potentials (VEPs) from the superior colliculus, the primary target of RGCs in the rodent brain. An interesting finding during the course of my thesis was that there is a substantial loss of retinal capillaries and a reduction in retinal blood that correlates with RGC loss in experimental glaucoma. Interestingly, galantamine also promoted the protection of the microvasculature and improved retinal blood flow in ocular hypertensive animals (Almasieh et al. in preparation). Importantly, I demonstrated that galantamine-mediated neuro- and vasoprotection occur through activation of muscarinic acetylcholine receptors. In the second part of my thesis, I investigated the role of oxidative stress and the use of reducing compounds to test the hypothesis that blockade of a superoxide burst may delay RGC death in experimental glaucoma. I took advantage of a novel phosphinevi borane based antioxidant compound available to us (PB1) to investigate its neuroprotective effect and mechanism of action in experimental glaucoma. The data demonstrate that intraocular administration of PB1 resulted in significant protection of RGC soma and axons. I also explored the molecular pathways leading to PB1-mediated neuronal survival by analyzing the components of survival and apoptotic signaling pathways involved in this response. My results show that PB1-mediated RGC survival did not correlate with inhibition of stress-activated protein kinase signaling, including ASK1, JNK or p38. Instead, PB1 led to a striking increase in retinal BDNF levels and downstream activation of the pro-survival ERK1/2 pathway (Almasieh et al. Journal of Neurochemistry, 2011). In conclusion, the findings presented in this thesis contribute to a better understanding of the pathological mechanisms underlying RGC loss in glaucoma and might provide insights into the design of novel neuroprotective and vasoprotective strategies for the treatment and management of this disease.