Les cellules gliales sont essentielles au fonctionnement du système nerveux. Dans la rétine, les cellules gliales de Müller assurent à la fois l’homéostasie du tissu et la protection des neurones, notamment celle des cellules ganglionnaires de la rétine (CGRs). L’hypothèse principale de la thèse est que les cellules de Müller joueraient un rôle primordial dans la survie neuronale tant au plan de la signalisation des neurotrophines/proneurotrophines par suite d’une blessure que lors des mécanismes d’excitotoxicité. Contrairement au brain-derived neurotrophic factor (BDNF), le nerve growth factor (NGF) n’est pas en mesure d’induire la survie des CGRs après une section du nerf optique. Le premier objectif de la thèse a donc été de localiser les récepteurs p75NTR et TrkA du NGF dans la rétine adulte et d’établir leur fonction respective en utilisant des ligands peptidomimétiques agonistes ou antagonistes spécifiques pour chacun des récepteurs. Nos résultats ont démontré que TrkA est surexprimé par les CGRs après l’axotomie, tandis que p75NTR est spécifiquement exprimé par les cellules de Müller. Alors que NGF n’est pas en mesure d’induire la survie des CGRs, l’activation spécifique de TrkA par des ligands peptidomimétique est nettement neuroprotectrice. De façon surprenante, le blocage sélectif de p75NTR ou l’absence de celui-ci protège les CGRs de la mort induite par l’axotomie. De plus, la combinaison de NGF avec l’antagoniste de p75NTR agit de façon synergique sur la survie des CGRS. Ces résultats révèlent un nouveau mécanisme par lequel le récepteur p75NTR exprimé par les cellules gliales de Müller peut grandement influencer la survie neuronale. Ensuite, nous avons voulu déterminer l’effet des proneurotrophines dans la rétine adulte. Nous avons démontré que l’injection de proNGF induit la mort des CGRs chez le rat et la souris par un mécanisme dépendant de p75NTR. L’expression de p75NTR étant exclusive aux cellules de Müller, nous avons testé l’hypothèse que le proNGF active une signalisation cellulaire non-autonome qui aboutit à la mort des CGRs. En suivant cette idée, nous avons montré que le proNGF induit une forte expression du tumor necrosis factor α (TNFα) dans les cellules de Müller et que l’inhibition du TNF bloque la mort neuronale induite par le proNGF. L’utilisation de souris knock-out pour la protéine p75NTR, son co-récepteur sortiline, ou la protéine adaptatrice NRAGE a permis de montrer que la production de TNF par les cellules gliales était dépendante de ces protéines. Le proNGF semble activer une signalisation cellulaire non-autonome qui cause la mort des neurones de façon dépendante du TNF in vivo. L’hypothèse centrale de l’excitotoxicité est que la stimulation excessive des récepteurs du glutamate sensibles au N-Methyl-D-Aspartate (NMDA) est dommageable pour les neurones et contribue à plusieurs maladies neurodégénératives. Les cellules gliales sont soupçonnées de contribuer à la mort neuronale par excitotoxicité, mais leur rôle précis est encore méconnu. Le dernier objectif de ma thèse était d’établir le rôle des cellules de Müller dans cette mort neuronale. Nos résultats ont démontré que l’injection de NMDA induit une activation du nuclear factor κB (NF-κB) dans les cellules de Müller, mais pas dans les CGRs, et que l’utilisation d’inhibiteurs du NF-κB empêche la mort des CGRs. De plus, nous avons montré que les cellules de Müller en réaction à l’activation du NF-κB produisent la protéine TNFα laquelle semble être directement impliquée dans la mort des CGRs par excitotoxicité. Cette mort cellulaire se produit principalement par l’augmentation à la surface des neurones des récepteurs AMPA perméables au Ca2+, un phénomène dépendant du TNFα. Ces donnés révèlent un nouveau mécanisme cellululaire non-autonome par lequel les cellules gliales peuvent exacerber la mort neuronale lors de la mise en jeu de mécanismes excitotoxiques. / Glial cells are essential for the functioning of the nervous system. In the retina, the Müller glial cells ensure the homeostasis of this tissue as well as the protection of neurons including the retinal ganglion cells (RGCs). The main hypothesis of this thesis is that Müller cells play a predominant role in neuronal survival both at the levels of neurotrophin/proneurotrophin signaling following injury and excitotoxic mechanisms. Unlike the brain-derived neurotrophic factor (BDNF), the nerve growth factor (NGF) is unable to induce RGCs survival following optic nerve transection. The first objective of the thesis was therefore to describe the expression of the two receptors of NGF, p75NTR and TrkA, in the adult retina and to address their functional role by using peptidomimetic agonistic or antagonistic ligands specific for each receptor. Our results showed that TrkA is overexpressed by RGCs following axotomy, whereas p75NTR is specifically expressed by Müller cells. While NGF by itself does not promote RGC survival, selective activation of TrkA receptors using peptidomimetic ligands is markedly neuroprotective. Surprisingly, selective blockers of p75NTR, or the absence of p75NTR, protect RGCs from axotomy-induced death. Moreover, combination of NGF or TrkA agonists with p75NTR antagonists functions synergistically to enhance RGC survival. These results reveal a new mechanism by which p75NTR expression by Müller glia may profoundly influence neuronal survival. Next, we wanted to address the effect of proneurotrophins in the adult retina. We showed that injection of proNGF induces the death of RGCs in rats and mice by a p75NTR-dependent signaling mechanism. Expression of p75NTR in the adult retina being confined to Müller glial cells, we tested the hypothesis that proNGF activates a non-cell autonomous signaling pathway to induce RGC death. Consistent with this notion, we showed that proNGF induced a robust expression of tumor necrosis factor α (TNFα) in Müller cells, and that genetic or biochemical ablation of TNFα blocked proNGF-induced death of retinal neurons. Mice rendered null for p75NTR, its co-receptor sortilin, or the adaptor protein NRAGE were defective in proNGF-induced glial TNFα production and did not undergo proNGF-induced retinal ganglion cell death. We concluded that proNGF activates a non-cell autonomous signaling pathway that causes TNFα-dependent death of retinal neurons in vivo. The central hypothesis of excitotoxicity is that excessive stimulation of neuronal N-Methyl-D-Aspartate (NMDA)-sensitive glutamate receptors is harmful to neurons and contributes to a variety of neurological disorders. Glial cells have been proposed to participate in excitotoxic neuronal loss, but their precise role is poorly defined. In this in vivo study, we showed that NMDA induces a strong NF-κB activation in Müller glia, but not in retinal neurons. Intriguingly, NMDA-induced death of retinal neurons was effectively blocked by inhibitors of NF-κB activity. We demonstrated that TNFα protein produced in Müller glial cells via an NMDA-induced NF-κB dependent pathway plays a crucial role in the excitotoxic loss of retinal neurons. This cell loss occurs mainly through a TNFα-dependent increase in Ca2+-permeable AMPA receptors on susceptible neurons. Thus, our data reveal a novel non-cell-autonomous mechanism by which glial cells can profoundly exacerbate neuronal death following excitotoxic injury.

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

Indiana University-Purdue University Indianapolis (IUPUI) / Nerve growth factor (NGF) is a neurotrophin upregulated with injury and inflammation. Peripheral administration of NGF causes hyperalgesia and allodynia in animals. Blocking NGF signaling reverses these effects. At the cellular level, chronic exposure of sensory neurons to NGF enhances expression the neurotransmitter, calcitonin gene-related peptide (CGRP). Acute exposure to NGF increases capsaicin-evoked CGRP release from sensory neurons in culture. Thus, NGF increases peptide release from neurons by: (1) increasing expression of peptides, and/or (2) altering their sensitivity. The increase in peptide outflow by either mechanism could contribute to development of hyperalgesia and allodynia. The signaling cascades mediating the actions of NGF in sensory neurons are unclear. Therefore, experiments were designed to determine which pathways regulate changes in iCGRP content and evoked release from primary sensory neurons in culture. The Ras/MEK/ERK cascade was identified as a possible regulator of iCGRP expression in response to NGF. To test this pathway, it was manipulated in neurons by (1) expression of dominant negative or constitutively active isoforms of Ras, (2) farnesyltransferase inhibition, (3) manipulation of the RasGAP, synGAP, and (4) blocking MEK activity. When the pathway was blocked, the NGF-induced increase in iCGRP expression was attenuated. When the Ras pathway was activated, iCGRP expression increased. These data indicate that Ras, and downstream signaling kinases, MEK and ERK, regulate the NGF-induced increases in CGRP in sensory neurons. To determine which pathway(s) regulate the increase in capsaicin-evoked iCGRP release upon brief exposure to NGF, the Ras/MEK/ERK pathway was manipulated as described above, and pharmacological inhibitors of the PI3 kinase, PLC, and Src kinase pathways were used. There were no differences observed in NGF-sensitization when the Ras and PI3 kinase pathways were inhibited, suggesting these two pathways were not involved. However, when the Src kinase inhibitor PP2 was used, the NGF-induced increase in release was completely blocked. Furthermore, the PKC inhibitor, BIM, also inhibited the sensitization by NGF. This data indicate Src and PKC regulate of sensitivity of sensory neurons in response to brief exposure to NGF. Thus, there is differential regulation of iCGRP content and evoked release from sensory neurons in response to NGF.

No description available.

Els trastorns de la conducta alimentària (TCA) tenen una etiologia complexa en la que hi intervenen factors de predisposició socioculturals, ambientals i genètics. S'ha aprofundit en les bases moleculars dels TCA mitjançant estudis en pacients i en models murins. S'ha descrit una alteració en la concentració de BDNF en plasma de pacients, una correlació d'aquests nivells amb trets psicopatològics, i una associació de determinats polimorfismes a bulímia nerviosa i als nivells de BDNF en plasma. Un estudi d'associació en vàries poblacions ha demostrat una forta associació de variants del gen NTRK3, amb epistasi amb NGF, a TCA. Un model de sobreexpressió de BDNF confirma el seu paper en la regulació del pes corporal i estableix un possible vincle entre BDNF i la fisiopatologia de les tremolors. La caracterització del ratolí anx/anx suggereix que pot ser un model de la síndrome caquètica que acompanya malalties com el càncer, la SIDA o les malalties autoimmunitàries. / Eating disorders (ED) are complex disorders were environmental, sociocultural and genetic factors are involved. We have improved the knowledge of the genetic basis of ED through studies involving ED patients and murine models. Altered BDNF blood levels have been linked to ED and its related psychopathological traits. In addition several polymorphisms in the BDNF gene have been associated to bulimia nervosa and BDNF plasma levels. A family based association study has shown a strong association of NTRK3 variants to ED which show epistasis with NGF. The generation of an overexpression mouse model for BDNF confirms its role in body weight regulation and establishes a possible link between BDNF and the pathophysiology of tremors. The characterization of the anx/anx mouse model suggests that it may be a good model for the cachexia syndrome that accompanies certain chronic or inflammatory diseases such as cancer, AIDS or autoimmune diseases.

No description available.

Dor pélvica crônica (DPC) afeta grande númerode mulheres e seu manejo ainda permanece complexo e insatisfatório. Estudos têm demonstrado um envolvimento do fator de crescimento neuronal (FCN) no processo de cronificação da dor. Participação hormonal neste processo também tem sido aventada, visto autores terem demonstrado influência estro/progestacional sobre nociceptores tanto direta quanto indiretamente através da influência exercida sobre os fatores neurotróficos. Foi objetivo deste estudo, verificar a associação entre a expressão do fator de crescimento neuronal (FCN), seu receptor (trk A) e os receptores de estrogênio e progesterona no peritôneo pélvico com a presença de dor pélvica crônica. Para tal foi realizado um estudo transversal incluindo um grupo de 22 mulheres com DPC, 8 com DPC e usuárias de anticoncepcional oral (DPC/ACO) e 7 sem dor. A dor foi analisada pela escala analógica visual (EAV) e questionário de McGill. Foi realizado imunohistoquímica para avaliar FCN e seu receptor trk A, receptores de estrogênio (RE) e progesterona (RP). A expressão de FCN teve media de 5, variando de 0 a 8, no grupo DPC, 5,5 no grupo DPC/ACO variando 3 a 8, e no grupo sem dor de 5 variando de 3 a 8 (p>0,05). A expressão de trk A apresentou media de 6, variandode 3 a 8, no grupo DPC, 6 no grupo DPC/ACO, variando de 4 a 8, e 6 no grupo sem dor variando de 4 a 6 (p>0,05). A expressão do RE apresentou média 4 no grupo DPC, variando de 0 a 8, 3,5 no grupo DPC/ACO variando de 0 a 8, e 7 no grupo sem dor, variando de 6 a 8 (p<0,05). A expressão do RP teve média 6,5 no grupo DPC, variando de 0 a 8, 5 no grupo DPC/ACO, variando de 0 a 7, e 7 no grupo sem dor, variando de 5 a 8 (p>0,05). Nossos resultados sugerem um papel anti-nociceptivo do estrogênio no peritôneo pélvico de mulheres no menacme, não mediado por expressão de FCN ou trk A. / Chronic pelvic pain (CPP) affects a great number of women and its management still remains complex and unsatisfactory. Studies have shown an involvement of the neuronal growing factor (NGF) in the process of permanence of pain. Hormonal participation in this process has also been put forward, as some authors have demonstrated estro/progestational influence under nociceptors direct or indirectly through their influence on neurotrofic factors. This study aimed to verify the association among the expression of neuronal growing factor (NGF), its receptor (TrKA) and the estrogen and progesterone receptors in the pelvic peritoneum with the presence of chronic pelvic pain. A transversal study was carried out including a group of 22 women with CPP, 8 with CPP and users of oral anticonceptional (CPP/OAC) and 7 without pain. The pain was analized by the visual analogic scale (VAS) and McGill\'s questionnaire. Imunehistochemical was performed to evaluate the NGF and its receptor TrKA, estrogen (ER) and progesteron (PR) receptors. The expression of NGF was an average of 5, varying from 0 to 8, in group CPP, 5,5 in group CPP/ OAC varying from 3 to 8, and in the group without pain varying from 3 to 8 (p>0,05). The expression of TrKA presented an average of 6, varying from 3 to 8, in the group CPP, 6 in the group CPP/OAC, varying from 4 to 8, and 6 in the group without pain varying from 4 to 6 (p>0,05). The expression of ER presented an average of 4 in the group CPP, varying from 0 to 8, 3,5 in group CPP/OAC varying from 0 to 8, and 7 in group without pain, varying from 6 to 8 (p<0,05). The expression of PR had an average 6,5 in the group CPP, varying from 0 to 8,5 in the group CPP/OAC, varying from 0 to 7, and 7 in the group without pain, varying from 5 to 8 (p>0,05). Our studies suggest an anti- nociceptive rule of estrogen in the pelvic peritoneum of women in menacme, not mediated by expression of NGF or TrKA.

Dor pélvica crônica (DPC) afeta grande númerode mulheres e seu manejo ainda permanece complexo e insatisfatório. Estudos têm demonstrado um envolvimento do fator de crescimento neuronal (FCN) no processo de cronificação da dor. Participação hormonal neste processo também tem sido aventada, visto autores terem demonstrado influência estro/progestacional sobre nociceptores tanto direta quanto indiretamente através da influência exercida sobre os fatores neurotróficos. Foi objetivo deste estudo, verificar a associação entre a expressão do fator de crescimento neuronal (FCN), seu receptor (trk A) e os receptores de estrogênio e progesterona no peritôneo pélvico com a presença de dor pélvica crônica. Para tal foi realizado um estudo transversal incluindo um grupo de 22 mulheres com DPC, 8 com DPC e usuárias de anticoncepcional oral (DPC/ACO) e 7 sem dor. A dor foi analisada pela escala analógica visual (EAV) e questionário de McGill. Foi realizado imunohistoquímica para avaliar FCN e seu receptor trk A, receptores de estrogênio (RE) e progesterona (RP). A expressão de FCN teve media de 5, variando de 0 a 8, no grupo DPC, 5,5 no grupo DPC/ACO variando 3 a 8, e no grupo sem dor de 5 variando de 3 a 8 (p>0,05). A expressão de trk A apresentou media de 6, variandode 3 a 8, no grupo DPC, 6 no grupo DPC/ACO, variando de 4 a 8, e 6 no grupo sem dor variando de 4 a 6 (p>0,05). A expressão do RE apresentou média 4 no grupo DPC, variando de 0 a 8, 3,5 no grupo DPC/ACO variando de 0 a 8, e 7 no grupo sem dor, variando de 6 a 8 (p<0,05). A expressão do RP teve média 6,5 no grupo DPC, variando de 0 a 8, 5 no grupo DPC/ACO, variando de 0 a 7, e 7 no grupo sem dor, variando de 5 a 8 (p>0,05). Nossos resultados sugerem um papel anti-nociceptivo do estrogênio no peritôneo pélvico de mulheres no menacme, não mediado por expressão de FCN ou trk A. / Chronic pelvic pain (CPP) affects a great number of women and its management still remains complex and unsatisfactory. Studies have shown an involvement of the neuronal growing factor (NGF) in the process of permanence of pain. Hormonal participation in this process has also been put forward, as some authors have demonstrated estro/progestational influence under nociceptors direct or indirectly through their influence on neurotrofic factors. This study aimed to verify the association among the expression of neuronal growing factor (NGF), its receptor (TrKA) and the estrogen and progesterone receptors in the pelvic peritoneum with the presence of chronic pelvic pain. A transversal study was carried out including a group of 22 women with CPP, 8 with CPP and users of oral anticonceptional (CPP/OAC) and 7 without pain. The pain was analized by the visual analogic scale (VAS) and McGill\'s questionnaire. Imunehistochemical was performed to evaluate the NGF and its receptor TrKA, estrogen (ER) and progesteron (PR) receptors. The expression of NGF was an average of 5, varying from 0 to 8, in group CPP, 5,5 in group CPP/ OAC varying from 3 to 8, and in the group without pain varying from 3 to 8 (p>0,05). The expression of TrKA presented an average of 6, varying from 3 to 8, in the group CPP, 6 in the group CPP/OAC, varying from 4 to 8, and 6 in the group without pain varying from 4 to 6 (p>0,05). The expression of ER presented an average of 4 in the group CPP, varying from 0 to 8, 3,5 in group CPP/OAC varying from 0 to 8, and 7 in group without pain, varying from 6 to 8 (p<0,05). The expression of PR had an average 6,5 in the group CPP, varying from 0 to 8,5 in the group CPP/OAC, varying from 0 to 7, and 7 in the group without pain, varying from 5 to 8 (p>0,05). Our studies suggest an anti- nociceptive rule of estrogen in the pelvic peritoneum of women in menacme, not mediated by expression of NGF or TrKA.

Les glandes salivaires sont des glandes mixtes : la salive (produit exocrine) estimpliquée dans le maintien de l'homéostasie buccale alors que les secrétions endocrines (ex :facteurs de croissance) ont un rôle physiologique (gamétogénèse, ostéogenèse,hypertension...) Chez les mammifères, elles affichent un dimorphisme sexuel qui laisseentrevoir une sensibilité éventuelle à des xeno-hormones.Ce mémoire présente l'action de la génistéine (phyto-oestrogène) et/ou de la vinclozoline(anti-androgène) sur la glande submandibulaire (SM) de rat lors d'une exposition précoce viala mère (gestation-lactation) et lors d'une exposition pendant la période de croissance (dusevrage à l'âge adulte). Les glandes SM, prélevées au stade immature et jeune adulte, ont faitl'objet d'une analyse histologique et d'une étude de marqueurs moléculaire des fonctionsendocrines et exocrines associées aux processus gustatifs. L'exposition précoce ralenti ledéveloppement de la glande SM et augmente sélectivement la préférence au sucré des malesimmatures mais pas des adultes ; l'analyse moléculaire révèle une action sélective sur lesfonctions exocrines corrélée à celle sur les préférences, ainsi qu'une action sur les fonctionsendocrines (facteurs de croissances) qui s'inverse avec l'âge. L'exposition à partir du sevrageperturbe seulement les mâles qui présentent des altérations des structures sécrétrices coupléesà des modifications d'expression des récepteurs hormonaux et facteurs de croissance, maisaussi au taux sérique de l'EGF.Cette étude identifie la glande submandibulaire comme cible de perturbateurs endocriniens etpose la question des conséquences physiologiques à terme

The thesis entitled “Syntheses and Characterization of Novel Materials for Efficacious Anticancer Drug Delivery and Selective Sensing of Bioanalytes” encompasses the syntheses and characterization of various novel materials those are primarily used for efficacious pH-targeted chemotherapy, selective sensing and quantification of ATP inside a single living cell and also for specific sensing of female sex pheromone of certain agriculturally important pests. In recent era of cancer research, pH guided anticancer drug delivery is an emerging field by which not only the drug-sensitive, but also the drug-resistant cancer cell lines can be targeted efficiently. Scientists have paid lot of attentions to this area of research to design biocompatible, pH-responsive drug delivery vehicles, where most of the literatures are end up with complex, elaborated synthetic procedures and use of expensive chemicals. There are only a few reports in the literature on small molecule based drug delivery vehicles, which is not well explored. Herein some of the biocompatible, pH-sensitive lipid and short peptide sequences are synthesized in easy and short synthetic procedures and successfully tested for their efficacious anticancer drug delivery properties by various biophysical and biological techniques. A pH and reduction dual bio-responsive short peptide sequences are also generated in simple steps for the same cause. The formation of different nanostructures from the self-assembly of these short peptides is probed from high level of theoretical calculations and ultimately a well known chemotherapeutic drug, doxorubicin, has been delivered efficiently both to the drug-sensitive and drug-resistant cancer cell lines. In a particular case, in vivo study has also been performed to establish the drug delivery efficacy of those serum-stable vehicles that led to proficient reduction of tumour volume as compared to the free drug. On the other hand, a few of the molecules are synthesized and characterized by various analytical means for the selective sensing and quantification of adenosine 5’-triphosphate (ATP) inside a single living cell. Unique surface functionalized templates are also fabricated over MEMS devices for specific sensing of female sex pheromone of Helicoverpa armigera and Bactocera oleae pest in an agricultural field to detect the early pest infestation. Toward this end, an extensive study on the design, syntheses and characterization of different novel materials is presented below.