Thesis (M.S.)--Miami University, Dept. of Zoology, 2004. / Title from first page of PDF document. Includes bibliographical references (p. 36-47).

OBJETIVO: Confirmar, em uma amostra de jovens provenientes da população geral, achados recentes em relação à fisiopatologia do transtorno bipolar. Foi escopo desta investigação avaliar diferenças em uma neurotrofina, dois marcadores de dano oxidativo, duas citocinas pró-inflamatórias e uma antiinflamatória entre grupos de participantes com transtorno bipolar, depressão maior e também pessoas sem quaisquer episódios de humor. Nominalmente, foram elas o fator neurotrófico derivado do cérebro (brain-derived neurotrophic factor, BDNF), conteúdo de substâncias reativas ao ácido tiobarbitúrico (thiobarbituric acid reactive substances, TBARS), o conteúdo de proteína carbonil (protein carbonyl content, PCC), o fator de necrose tumoral-alfa (tumor necrosis factor-alpha, TNF-α), a interleucina-6 (IL-6) e a interleucina-10 (IL-10). MÉTODO: Indivíduos provenientes da população geral, que haviam participado de um estudo transversal (n=1560), com um rastreamento positivo para o transtorno bipolar foram recrutados, bem como dois grupos de controles. O primeiro tinha apenas episódios depressivos e o segundo não tinha história de episódios de humor. Isso levou a uma amostra de 231 participantes que passou por confirmação diagnóstica com a Entrevista Clínica Estruturada para o DSM-IV. Todas as análises incluíram avaliação de associações bivariadas. Um modelo a priori que incluía sexo, classe social, estado atual de humor, uso de substâncias e grupo diagnóstico como preditores foi utilizado. RESULTADOS: A amostra final foi composta por 55 participantes com transtorno bipolar, 82 com depressão maior e 95 controles. Uma minoria (9,6%) utilizava medicações psiquiátricas quando da entrevista. O transtorno bipolar foi associado a níveis circulantes elevados de PCC e TNF-α quando comparado com o grupo controle. A depressão maior também foi associada a níveis elevados de PCC quando comparada com o grupo sem episódios de humor. O uso de medicações psiquiátricas se associou com níveis mais baixos de TNF-α. As correlações entre os marcadores não foram tão fortes quanto em amostras clínicas anteriores. CONCLUSÕES: Os resultados encontrados apontam para duas conclusões mais amplas. Primeiramente, o transtorno bipolar se associa com um estado pró-oxidante e pró-inflamatório desde fases iniciais. Em segundo lugar, essas alterações parecem mais sutis que as observadas em amostras clínicas compostas por pessoas com doença crônica, o que reforçaria a idéia da ocorrência de algum tipo de progressão da doença. O principal cuidado com esses resultados é que provêm de amostras transversais, não longitudinais. Isso faz com que causalidade não possa ser inferida, e permanece a possibilidade que outros fatores além da doença bipolar sejam responsáveis pela toxicidade sistêmica observada. / OBJECTIVE: The aim of this study was to confirm, in a sample of young adults from the general population, recent findings regarding the pathophysiology of bipolar disorder. The focus of this investigation was finding group differences in one neurotrophin, two markers of oxidative damage, two pro-inflammatory cytokines and one anti-inflammatory cytokine in participants with bipolar disorder, major depression and people without any mood episodes. Markers assessed here were brain-derived neurotrophic factor (BDNF), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10). METHOD: Individuals from the general population, previously included in a cross-sectional study (n=1560), with a positive screen for bipolar disorder were recruited, as well as two groups of controls. One had only depressive episodes and the other had no history of mood episodes. This yielded a sample of 231 participants that further underwent diagnostic confirmation with the Structured Clinical Interview for DSM-IV (SCID). All analyses included a check for bivariate associations as well as an a priori multivariate model with sex, social class, current mood state, use of substances and SCID diagnoses as predictors. RESULTS: The final sample included 55 participants with bipolar disorder, 82 with major depression and 95 healthy controls. Only a minority was using any psychiatric medications (9.6%). Bipolar disorder was associated with higher PCC and TNF-α levels when compared to the control group. Major depression was also associated with higher PCC levels when compared to the control condition. Use of psychiatric medication was associated with lower TNF-α levels. Correlations between the same markers were not as strong as in clinical samples. CONCLUSIONS Two broad conclusions are called for from these results. The first is that early-stage bipolar disorder is already associated with a pro-oxidant, pro-inflammatory state. The second is that these changes appear more subtle than those observed in typical late-stage, chronic patients, supporting the notion that a form of illness progression takes place. The main caveat is that this data is cross-sectional, not longitudinal. This precludes causal inferences as factors other than the bipolar illness can conceivably induce systemic toxicity.

OBJETIVO: Confirmar, em uma amostra de jovens provenientes da população geral, achados recentes em relação à fisiopatologia do transtorno bipolar. Foi escopo desta investigação avaliar diferenças em uma neurotrofina, dois marcadores de dano oxidativo, duas citocinas pró-inflamatórias e uma antiinflamatória entre grupos de participantes com transtorno bipolar, depressão maior e também pessoas sem quaisquer episódios de humor. Nominalmente, foram elas o fator neurotrófico derivado do cérebro (brain-derived neurotrophic factor, BDNF), conteúdo de substâncias reativas ao ácido tiobarbitúrico (thiobarbituric acid reactive substances, TBARS), o conteúdo de proteína carbonil (protein carbonyl content, PCC), o fator de necrose tumoral-alfa (tumor necrosis factor-alpha, TNF-α), a interleucina-6 (IL-6) e a interleucina-10 (IL-10). MÉTODO: Indivíduos provenientes da população geral, que haviam participado de um estudo transversal (n=1560), com um rastreamento positivo para o transtorno bipolar foram recrutados, bem como dois grupos de controles. O primeiro tinha apenas episódios depressivos e o segundo não tinha história de episódios de humor. Isso levou a uma amostra de 231 participantes que passou por confirmação diagnóstica com a Entrevista Clínica Estruturada para o DSM-IV. Todas as análises incluíram avaliação de associações bivariadas. Um modelo a priori que incluía sexo, classe social, estado atual de humor, uso de substâncias e grupo diagnóstico como preditores foi utilizado. RESULTADOS: A amostra final foi composta por 55 participantes com transtorno bipolar, 82 com depressão maior e 95 controles. Uma minoria (9,6%) utilizava medicações psiquiátricas quando da entrevista. O transtorno bipolar foi associado a níveis circulantes elevados de PCC e TNF-α quando comparado com o grupo controle. A depressão maior também foi associada a níveis elevados de PCC quando comparada com o grupo sem episódios de humor. O uso de medicações psiquiátricas se associou com níveis mais baixos de TNF-α. As correlações entre os marcadores não foram tão fortes quanto em amostras clínicas anteriores. CONCLUSÕES: Os resultados encontrados apontam para duas conclusões mais amplas. Primeiramente, o transtorno bipolar se associa com um estado pró-oxidante e pró-inflamatório desde fases iniciais. Em segundo lugar, essas alterações parecem mais sutis que as observadas em amostras clínicas compostas por pessoas com doença crônica, o que reforçaria a idéia da ocorrência de algum tipo de progressão da doença. O principal cuidado com esses resultados é que provêm de amostras transversais, não longitudinais. Isso faz com que causalidade não possa ser inferida, e permanece a possibilidade que outros fatores além da doença bipolar sejam responsáveis pela toxicidade sistêmica observada. / OBJECTIVE: The aim of this study was to confirm, in a sample of young adults from the general population, recent findings regarding the pathophysiology of bipolar disorder. The focus of this investigation was finding group differences in one neurotrophin, two markers of oxidative damage, two pro-inflammatory cytokines and one anti-inflammatory cytokine in participants with bipolar disorder, major depression and people without any mood episodes. Markers assessed here were brain-derived neurotrophic factor (BDNF), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10). METHOD: Individuals from the general population, previously included in a cross-sectional study (n=1560), with a positive screen for bipolar disorder were recruited, as well as two groups of controls. One had only depressive episodes and the other had no history of mood episodes. This yielded a sample of 231 participants that further underwent diagnostic confirmation with the Structured Clinical Interview for DSM-IV (SCID). All analyses included a check for bivariate associations as well as an a priori multivariate model with sex, social class, current mood state, use of substances and SCID diagnoses as predictors. RESULTS: The final sample included 55 participants with bipolar disorder, 82 with major depression and 95 healthy controls. Only a minority was using any psychiatric medications (9.6%). Bipolar disorder was associated with higher PCC and TNF-α levels when compared to the control group. Major depression was also associated with higher PCC levels when compared to the control condition. Use of psychiatric medication was associated with lower TNF-α levels. Correlations between the same markers were not as strong as in clinical samples. CONCLUSIONS Two broad conclusions are called for from these results. The first is that early-stage bipolar disorder is already associated with a pro-oxidant, pro-inflammatory state. The second is that these changes appear more subtle than those observed in typical late-stage, chronic patients, supporting the notion that a form of illness progression takes place. The main caveat is that this data is cross-sectional, not longitudinal. This precludes causal inferences as factors other than the bipolar illness can conceivably induce systemic toxicity.

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A forma digestiva decorrente da doença de Chagas é uma das principais causas de morbidade e mortalidade na fase crônica da doença. Pacientes portadores da forma digestiva apresentam uma série de sintomas relacionados à obstrução do órgão. No megacólon, os órgãos exibem grande aumento do lúmen e hipertrofia da camada muscular. Análises histológicas dos órgãos afetados têm demonstrado lesões inflamatórias do sistema nervoso entérico (SNE), associadas com uma grande redução no número de neurônios. Embora o mecanismo de lesão neuronal continue obscuro, a frequente observação de ganglionite e periganglionite em pacientes com megacólon aponta para a participação de células do sistema imune nesse processo. Indivíduos não portadores de megacólon também apresentaram processos de denervação e inflamação, porém menos intensas em relação aos portadores de megacólon. Conhecendo que a inter-relação entre o SNE e o sistema imune é muito rica, é de extrema importância compreender os mecanismos que atuam em comum entre estes dois sistemas, o que pode elucidar e mostrar novos caminhos para o controle efetivo de doenças que afligem o trato gastrintestinal. Dados preliminares de nossos estudos utilizando a proteína GAP-43, marcador de regeneração neuronal, sugerem que esse processo de plasticidade neuronal esteja ocorrendo no cólon de pacientes portadores da infecção crônica. A hipótese é que o desenvolvimento do megacólon chagásico esteja intimamente relacionado com a expressão de neurotrofinas, substâncias capazes de estimular o processo de regeneração neuronal. A partir desses dados uma nova linha investigativa abriu-se no estudo da patologia do megacólon chagásico. Para a compreensão do desenvolvimento dessa patologia, avaliamos o grau de destruição das diferentes classes neuronais, a taxa de regeneração e as substâncias envolvidas com as mesmas, sendo essa a hipótese norteadora da dissertação aqui apresentada. / Patients with the digestive form of Chagas' disease exhibit a number of symptoms related to obstruction of the organ. Histological analysis of affected organs have demonstrated inflammatory lesions of the enteric nervous system (ENS), associated with a large reduction in the number of neurons caused, mainly, by inflammatory process. However, previous studies presented that some substances, like neurotrophins, may restrict neuronal destruction levels. The objective of this study is to characterize the neurotrophins expression in tissues from chagasic patients with chagasic megacolon and verify its involvement in megacolon development. For this, we used samples from chagasic patients with megacolon (n=8) and non-infected individuals (n=8) that, after preparation, were submitted to confocal fluorescence immunohistochemistry. To identify the sources and expression level of neurotrophins (NGF, GDNF and NT3), we performed a co-localization with Peripherin (neuronal marker) and S-100 (glial cell marker). Our results presented that, in the colon, the glial cells are the main sources of neurotrophins in all analyzed groups. Besides, chagasic patients with megacolon presented high expression of all investigated neurotrophins when compared with non-infected individuals. Our data point that neurotrophins might perform a protective role in the enteric nervous system and that prevent the megacolon installation. By the other side, chagasic patients that do not express an adequate level of neurotrophins may progress to megacolon form. We believe that this data can suggest new treatment protocols, like drugs administration qualified to elevate neurotrophins levels, what could prevent the megacolon installation and maintain the normal function of the gastrointestinal tract. / Dissertação (Mestrado)

OBJETIVO: Confirmar, em uma amostra de jovens provenientes da população geral, achados recentes em relação à fisiopatologia do transtorno bipolar. Foi escopo desta investigação avaliar diferenças em uma neurotrofina, dois marcadores de dano oxidativo, duas citocinas pró-inflamatórias e uma antiinflamatória entre grupos de participantes com transtorno bipolar, depressão maior e também pessoas sem quaisquer episódios de humor. Nominalmente, foram elas o fator neurotrófico derivado do cérebro (brain-derived neurotrophic factor, BDNF), conteúdo de substâncias reativas ao ácido tiobarbitúrico (thiobarbituric acid reactive substances, TBARS), o conteúdo de proteína carbonil (protein carbonyl content, PCC), o fator de necrose tumoral-alfa (tumor necrosis factor-alpha, TNF-α), a interleucina-6 (IL-6) e a interleucina-10 (IL-10). MÉTODO: Indivíduos provenientes da população geral, que haviam participado de um estudo transversal (n=1560), com um rastreamento positivo para o transtorno bipolar foram recrutados, bem como dois grupos de controles. O primeiro tinha apenas episódios depressivos e o segundo não tinha história de episódios de humor. Isso levou a uma amostra de 231 participantes que passou por confirmação diagnóstica com a Entrevista Clínica Estruturada para o DSM-IV. Todas as análises incluíram avaliação de associações bivariadas. Um modelo a priori que incluía sexo, classe social, estado atual de humor, uso de substâncias e grupo diagnóstico como preditores foi utilizado. RESULTADOS: A amostra final foi composta por 55 participantes com transtorno bipolar, 82 com depressão maior e 95 controles. Uma minoria (9,6%) utilizava medicações psiquiátricas quando da entrevista. O transtorno bipolar foi associado a níveis circulantes elevados de PCC e TNF-α quando comparado com o grupo controle. A depressão maior também foi associada a níveis elevados de PCC quando comparada com o grupo sem episódios de humor. O uso de medicações psiquiátricas se associou com níveis mais baixos de TNF-α. As correlações entre os marcadores não foram tão fortes quanto em amostras clínicas anteriores. CONCLUSÕES: Os resultados encontrados apontam para duas conclusões mais amplas. Primeiramente, o transtorno bipolar se associa com um estado pró-oxidante e pró-inflamatório desde fases iniciais. Em segundo lugar, essas alterações parecem mais sutis que as observadas em amostras clínicas compostas por pessoas com doença crônica, o que reforçaria a idéia da ocorrência de algum tipo de progressão da doença. O principal cuidado com esses resultados é que provêm de amostras transversais, não longitudinais. Isso faz com que causalidade não possa ser inferida, e permanece a possibilidade que outros fatores além da doença bipolar sejam responsáveis pela toxicidade sistêmica observada. / OBJECTIVE: The aim of this study was to confirm, in a sample of young adults from the general population, recent findings regarding the pathophysiology of bipolar disorder. The focus of this investigation was finding group differences in one neurotrophin, two markers of oxidative damage, two pro-inflammatory cytokines and one anti-inflammatory cytokine in participants with bipolar disorder, major depression and people without any mood episodes. Markers assessed here were brain-derived neurotrophic factor (BDNF), thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10). METHOD: Individuals from the general population, previously included in a cross-sectional study (n=1560), with a positive screen for bipolar disorder were recruited, as well as two groups of controls. One had only depressive episodes and the other had no history of mood episodes. This yielded a sample of 231 participants that further underwent diagnostic confirmation with the Structured Clinical Interview for DSM-IV (SCID). All analyses included a check for bivariate associations as well as an a priori multivariate model with sex, social class, current mood state, use of substances and SCID diagnoses as predictors. RESULTS: The final sample included 55 participants with bipolar disorder, 82 with major depression and 95 healthy controls. Only a minority was using any psychiatric medications (9.6%). Bipolar disorder was associated with higher PCC and TNF-α levels when compared to the control group. Major depression was also associated with higher PCC levels when compared to the control condition. Use of psychiatric medication was associated with lower TNF-α levels. Correlations between the same markers were not as strong as in clinical samples. CONCLUSIONS Two broad conclusions are called for from these results. The first is that early-stage bipolar disorder is already associated with a pro-oxidant, pro-inflammatory state. The second is that these changes appear more subtle than those observed in typical late-stage, chronic patients, supporting the notion that a form of illness progression takes place. The main caveat is that this data is cross-sectional, not longitudinal. This precludes causal inferences as factors other than the bipolar illness can conceivably induce systemic toxicity.

Made available in DSpace on 2016-03-15T19:40:17Z (GMT). No. of bitstreams: 1 Felipe Rodrigues Pinto.pdf: 488990 bytes, checksum: 8735cc0097d83b1a36638c054be80716 (MD5) Previous issue date: 2014-08-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The prevalence and incidence of obesity has increased in the western society and can be partially explained by the consumption of a high fat and sugar diet combined with a sedentary lifestyle. Obesity can lead to a condition known as Metabolic Syndrome, characterized by hyperglycemia, dyslipidemia, hypertension and insulin resistance. Furthermore, studies show that mice born from obese mothers have deficits in learning and memory. Those deficits may be caused by alteration in the production of neurotrophins, essential in the formation of the long term potentiation which is the base of the consolidation of long term memory. Hypothyroidism also affects the development of the Central Nervous System in the offspring and reduces cognitive performance in adults. Serum levels of thyroid hormones are constant and its availability for cells is dependent on the activity of deiodinases which may activate (D2) or inactivate (D3) the T4 into T3 or T3r, respectively. Moreover, neurotrophins that are kwon to be decreased in the brain of obese mothers also are positively regulated by the T3. This study tested the hypothesis that the maternal obesity leads to alteration in the expression of D3 in the offspring hippocampus. Even though the test used in this study has shown no prejudice in memory and learning in the offspring of obese mothers, a lower expression of D3 in the hippocampus was observed. Thus, is possible to conclude that the maternal obesity alters the thyroid hormone signaling in the offspring hippocampus. / A prevalência e a incidência da obesidade têm aumentado na sociedade ocidental e pode ser explicada em parte pelo consumo de uma dieta rica em gordura e carboidratos aliado à vida sedentária. A obesidade pode levar a uma condição conhecida como Síndrome Metabólica, que se caracteriza pela hiperglicemia, dislipidemia, hipertensão e resistência à insulina. Além disso, estudos mostram que camundongos nascidos de mães obesas apresentam déficits de aprendizado e memória. Esses déficits podem ser causados por alterações na produção de neurotrofinas, essenciais para a formação da potenciação de longa duração que é à base da consolidação da memória de longo prazo. O hipotireoidismo também afeta o desenvolvimento do SNC dos filhotes e piora o desempenho cognitivo de indivíduos adultos. Os níveis séricos de hormônio tiroidiano permanecem constantes e a sua disponibilidade para as células depende da atividade das desiodases que ativam, por meio da desiodase 2 (D2) ou inativam, por meio da desiodase 3 (D3) o T4 a T3 ou a T3r, respectivamente. Além disso, as neurotrofinas, que reconhecidamente estão diminuídas no cérebro de filhotes de mães obesas, também são positivamente reguladas pelo T3. O presente estudo testou a hipótese de que a obesidade materna leva à alteração na expressão da D3 em hipocampo dos filhotes. Nossos estudos mostraram que, embora os testes empregados não tenham evidenciado prejuízos na memória e aprendizado dos filhotes de mães obesas, observamos menor expressão da D3 no hipocampo. Assim, é possível concluir que a obesidade materna altera a sinalização do hormônio tireoidiano no hipocampo dos filhotes.

Les neurotrophines sont des facteurs de croissance initialement découverts dans le système nerveux et ayant pour rôle de contrôler la croissance, la prolifération et la survie des cellules neuronales et astrocytaires, mais aussi dans de nombreux autres tissus. Les neurotrophines peuvent interagir avec leurs récepteurs de haute affinité Trks. Les travaux précédemment réalisés au sein de notre équipe ont mis en évidence une boucle de régulation autocrine, en réponse à un stress cellulaire, et ce de façon dépendante des neurotrophines, notamment du BDNF, dans plusieurs lignées lymphocytaires B humaines, à différents stades de différenciation. Les cellules produisent du BDNF qui agit de manière autocrine sur son récepteur spécifique, TrkB. Le transport du BDNF est assuré par la sortiline, une protéine à domaine Vps10. Les neurotrophines sont également synthétisées sous forme de progéniteurs biologiquement actifs, les pro-neurotrophines. Le pro-BDNF interagit avec le récepteur aux neurotrophines à domaine de mort p75NTR, l’interaction du pro-BDNF avec le récepteur p75NTR et de son co-récepteur, la sortiline, induit l’apoptose des lymphocytes B. La sortiline est exprimée dans les lymphocytes B humains, les lignées de lymphocytaires B. La sortiline, également appelée NTSR3, peut lier un autre neuropeptide, la neurotensine (NTS). Identifiée, dans le système nerveux, où elle joue un rôle de neurotransmetteur, impliqué dans l’analgésie et la thermorégulation. Elle est également présente dans le tube digestif, où elle est impliquée dans la régulation de la digestion et le contrôle et de la glycémie. La fonction de la neurotensine est associée à l’activation de la sortiline mais aussi de ses deux récepteurs à protéine G, le récepteur de haute affinité, NTSR1 et le récepteur de faible affinité, NTSR2. La NTS est impliquée dans l’oncogenèse de nombreux cancers solides via sa liaison au récepteur NTSR1 principalement mais également au récepteur NTSR2, notamment dans un modèle de cancer prostatique. Nous avons démontré pour la première fois l’expression de la neurotensine et de ses récepteurs NTSR1 et NTSR2 dans les lymphocytes B humains. Le stress pro-apoptotique induit par la privation sérique favorise une relocalisation des récepteurs NTSR1 et sortiline à la membrane plasmique. Au sein de ces cellules, la neurotensine induit une augmentation de la prolifération et une diminution de l’apoptose. Ces effets de la NTS sont bloqués par l’inhibiteur de NTSR1, le SR48692/Meclinertant®. Les analyses transcriptionnelles ont détecté une surexpression du récepteur NTSR2 au sein des lymphocytes B purifiés de patients ayant une LLC et au niveau des ganglions de patients atteints de lymphomes B en revanche, l’expression de la neurotensine est réduite. La surexpression de NTSR2 induit l’activation transcriptionnelle de TrkB, autre récepteur exprimé par ces lignées comme par les cellules de LLC de patients. La co-localisation de ces 2 récepteurs a été démontrée. Ce complexe protéique induit l’activation des voies de signalisation ERK, p38MAPK et JNK, après traitement par le BDNF, le ligand de TrkB. Ces données suggèrent un phénomène de transactivation entre ces 2 récepteurs, dépendant des métalloprotéases. Le blocage de l’internalisation de ce complexe protéique, induit une augmentation de l’activation des voies de signalisation. Le trafic intra-cellulaire endosomal de ce complexe apparaît perturbé dans les cellules surexprimant NTSR2, ce qui pourrait conduire à son accumulation comme cela est détecté dans les cellules de LLC. Ces cellules leucémiques se caractérisent également par une production d’exosomes contenant le complexe TrkB/NTSR2, sécrété en extra-cellulaire et retrouvé en excès dans le plasma des patients en comparaison à des témoins volontaires sains. / Neurotrophins are growth factors, initially discovered in the nervous system and whose functions are implicated in the growth, proliferation and survival of neuronal cells and astrocytes, and also in many other tissues. Neurotrophins can interact with their high-affinity receptors Trks. Previous work in our team showed a neurotrophin-dependent survival autocrine loop in response to cellular stress, including BDNF in several human B cell lines at various stages of B lymphocytes differentiation. These cells produce BDNF which acts in an autocrine manner on its specific tyrosine kinase receptor, TrkB. BDNF transport is provided by a Vps10 domain protein named, sortilin. Neurotrophins are synthesized as biologically active precursors, pro-neurotrophins. The proBDNF may interact with a death domain neurotrophins receptor p75NTR. The interaction of proBDNF with the p75NTR receptor and its co-receptor sortilin, induces B cell apoptosis. Sortilin is expressed in human lymphocytic lines B. Sortilin can bind another neuropeptide, neurotensin (NTS) and also called NTSR3 (Neurotensin Receptor 3). Identified in the nervous system, where it acts as a neurotransmitter involved in analgesia and thermoregulation, NTS is also present in the digestive tract, and involved in the digestion and glucose regulations. Neurotensin functions are associated to the sortilin activation but also its two G-protein coupled receptors, the high and the low affinity receptors, NTSR1 and NTSR2 respectively. NTS is involved in the oncogenesis of many solid cancers, especialy by its binding to the receptor NTSR1 mainly, but also NTSR2 notably in a prostate cancer model. We have demonstrated for the first time the expression of neurotensin and its receptors NTSR1 and NTSR2 in human B lymphocytes. The pro-apoptotic stress induced by serum deprivation promotes relocation NTSR1 receptor sortilin and to the plasma membrane. Within these cells, neurotensin induces increased proliferation and decreased apoptosis. These effects are blocked by the NTSR1 antagonist, SR48692/Meclinertant®. Transcriptional analyzes have detected overexpression of the receptor NTSR2 in purified B cells from patients with CLL and in lymph nodes of B-cell lymphomas patients, in contrast, the expression neurotensin is reduced. Overexpression NTSR2 induced transcriptional activation of TrkB. This receptor is expressed by B cell lines and B cells of CLL patients. The co-localization of these 2 receptors was demonstrated. This protein complex induces the activation of signaling pathways ERK, JNK and p38MAPK, after treatment with BDNF, the TrkB ligand. These data suggest a transactivation between these two receptors, depending to the metalloproteas activation. The internalization blocking of this protein complex, induces its plasma membrane sequestration and induces an increase of the signaling pathways activation. The intracellular endosomal trafficking in cells overexpressing NTSR2 cells, as detected in CLL cells, appears disrupted, which might lead to the NTSR2/TrkB complex accumulation, and releasing to the extracellular environnement. These leukemic cells are also characterized by a production of exosomes containing the TrkB/NTSR2 complex, secreted to the extracellular environement and found in excess in the plasma of patients in comparison to healthy volunteers.

Les glioblastomes (GBM) sont des tumeurs astrocytaires au pronostic défavorable. L’échec des thérapies actuelles (chimio et radiothérapies) est principalement lié à la résistance des cellules souches cancéreuses (CSCs). Ces cellules ont besoin de communiquer en permanence avec leur microenvironnement pour leur survie et pour maintenir une niche favorable à leur développement. Le transfert de matériel entre les CSC, les cellules tumorales et le microenvironnement contribue à l’échappement thérapeutique. Des travaux récents révèlent l’importance des récepteurs aux neurotrophines TrkB et TrkC dans la survie et la croissance des CSC de GBM. Nos travaux préliminaires dans le cancer bronchique démontrent que les récepteurs aux neurotrophines sont transférés aux cellules du microenvironnement via les exosomes afin de les contrôler. Cependant, le mécanisme de diffusion de récepteurs oncogéniques à partir de CSC n’a jamais été étudié. Notre objectif principal était donc de déterminer l’implication des récepteurs des neurotrophines dans le transfert du phénotype agressif des CSC vers les cellules du microenvironnement afin de favoriser la résistance thérapeutique du glioblastome. Nos résultats ont permis d’établir un lien entre le stade de différenciation des cellules tumorales, l’expression des neurotrophines et leur interaction avec le microenvironnement tumoral via les exosomes. Le transfert de TrkB au sein des exosomes joue un rôle clé dans la progression tumorale du GBM et dans l’agressivité cellulaire. Néanmoins, le transfert des récepteurs aux neurotrophines via les exosomes pourrait également être impliqué dans les mécanismes de radiorésistance. Des études menées sur des cellules de GBM humain irradiées et traitées par des exosomes démontrent l’implication de ces derniers dans l’échappement thérapeutique. Parmi les cellules du microenvironnement ciblées par les exosomes, les CSM sont celles qui ont été les moins étudiées bien qu’elles possèdent un tropisme spécifique pour le GBM. Nos travaux démontrent que les exosomes de GBM modifient le phénotype des CSM et augmentent leurs capacités prolifératives et migratoires. La fonction exacte du transfert des récepteurs des neurotrophines devra être analysée dans ces différents modèles afin de préciser son importance dans la physiopathologie du glioblastome et sa progression. L’expression des récepteurs aux neurotrophines dans ces exosomes permet d’envisager leur utilisation en tant que biomarqueurs diagnostiques et/ou pronostiques dans le GBM. Mots clés : Glioblastomes, cellules souches cancéreuses, neurotrophines, TrkB, radiothérapie, cellules souches mésenchymateuses, exosomes. / Glioblastoma are tumors derived from astrocytes with a dark prognosis. Current therapies fail to inhibit relapses due to radioresistant properties of cancer stem cells (CSC). Communication between CSC and their microenvironment is required for maintain “stem cells niche” and cell survival . The transfer of materials between CSC, tumor cells and microenvironment contributes to therapeutic resistance. In glioma, recent studies reveal the major role of TrkB and TrkC in survival of CSC. Our previous work, in lung cancer, have shown that neurotrophin receptors exhibits a control on microenvironment cells and angiogenesis through exosome transfer. However, similar mechanism of oncogenic receptor transfer from CSC has never been studied. Our main goal was to determine the involvement of neurotrophin receptors in the transfer of biological aggressiveness to microenvironment cells in order to promote therapeutic resistance in glioblastoma. Our findings suggest a relationship between cell differentiation status, expression of neurotrophin receptors and their interaction with the microenvironment through exosomes. TrkB-containing exosomes play a key role in the control of glioblastoma progression and cell aggressiveness. Mechanisms of radioresistance might also be dependent of the transfer of neurotrophin receptors through exosomes. Indeed, our results on irradiated human GBM cells and treated by exosomes demonstrate the involvement of exosome in radioresistance mechanisms. Although mesenchymal stem cells (MSCs) are considered as stromal components of glioblastoma, their communication with CSC, particularly through exosomes, remain largely undefined. Our results show that GBM-derived exosomes modify the phenotype of MSCs and increase their proliferative and migratory abilities. The putative function of neurotrophin receptors transfer should be analyzed in these models to determine their prime role in glioblastoma pathogenesis and progression. This finding suggest that the neurotrophin receptor expression in exosomes could be used as diagnostis and prognosis biomarkers of GBM.

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