No description available.

Objective: The purpose of this study was to investigate the effects of noise exposure on the cervical vestibular evoked myogenic potential (cVEMP) in individuals with asymmetric noise-induced sensorineural hearing loss (NIHL). Design: A cross-sectional observational study was used to compare cVEMP characteristics in 43 individuals with a history of noise exposure greater in one ear (e.g., the left ear of a right-handed rifle shooter) and asymmetric sensorineural hearing loss consistent with the history of noise exposure and in 14 age-matched controls. The characteristics of hearing loss were examined further for the noise-exposed participants with abnormal cVEMPs and the noise-exposed participants with normal cVEMPs. Results: Thirty-three percent of the noise-exposed participants had abnormal cVEMPs, whereas cVEMPs were present and symmetrical in 100% of the age-matched controls, and cVEMP threshold was greater in the noise-exposed group than in the control group. Abnormal cVEMPs occurred most often in the ears with poorer hearing (or greater NIHL), and the noise-exposed participants who had abnormal cVEMPs had poorer high-frequency pure-tone thresholds (greater NIHL) and greater interaural high-frequency pure-tone threshold differences than the noise-exposed participants with normal cVEMPs. Conclusions: These findings are consistent with previous studies that suggest that the sacculocollic pathway may be susceptible to noise-related damage. There is emerging evidence that the severity of NIHL is associated with the presence or absence of cVEMPs.

Cervical vestibular-evoked myogenic potentials (cVEMPs) are recorded from the sternocleidomastoid muscle using air conduction or bone conduction acoustic stimuli, skull taps, or transmastoid current. The diagnostic usefulness of the cVEMP has been examined for various peripheral and central vestibulopathies. Recent reports indicate that it is possible to record short-latency ocular vestibular-evoked myogenic potentials (oVEMPs) from surface electrodes below the eyes in response to air conduction and bone conduction stimuli. Both methods provide diagnostic information about otolith function. This article provides an overview of each method and highlights the similarities and differences. Several cases are presented to illustrate the relation between the results for cVEMPs and oVEMPs in patients with well-defined audiovestibular disorders.

No description available.

No description available.

L’atteinte de la fonction endothéliale représente une phase précoce de l’athérosclérose, un stade où les patients sont généralement asymptomatiques. Il existe donc un intérêt certain à détecter la dysfonction endothéliale. Nous avons développé une technique de mesure des variations de flot artériel au niveau des membres supérieurs, basée sur la spectroscopie proche infrarouge (NIRS). Cette approche permettrait d’étudier le niveau d’atteinte vasculaire et probablement de quantifier le degré de dysfonction endothéliale périphérique lors d’une hyperémie réactive. L'expérience a été exécutée sur deux cohortes de 13 et de 15 patients et a été comparée à la pléthysmographie par jauge de contrainte (SGP) qui est considérée comme une méthode de référence. Par la suite, nous avons caractérisé la réponse endothéliale par modélisation de la courbe hyperémique du flot artériel. Des études préliminaires avaient démontré que la réponse hyperémique adoptait majoritairement une forme bi-modale. Nous avons tenté de séparer les composantes endothéliales-dépendantes et endothéliales-indépendantes de l’hyperémie. La quantification des deux composantes de la réaction hyperémique permet de calculer un indice de la ‘santé’ du système endothélial local. Cet indice est nommé le ηfactor. Les résultats montrent une forte corrélation des mesures de flots entre la technique développée et la méthode de référence (r=0.91). Nous avons conclu que NIRS est une approche précise pour la mesure non-invasive du flot artériel. Nous avons obtenu une bonne répétabilité (ICC = 0.9313) pour le ηfactor indiquant sa robustesse. Cependant des études supplémentaires sont nécessaires pour valider la valeur de diagnostic du facteur défini. Mots clés: hyperémie réactive, réponse myogénique, oxyde nitrique, athérosclérose, spectroscopie proche infrarouge / Atherosclerotic diseases are mainly caused by coronary and peripheral blood vessel disorders. Endothelial dysfunction represents an early phase in these diseases, when patients are generally asymptomatic. We developed a technique, based on near infrared spectroscopy (NIRS), for measurement of arterial blood flow variations in limbs during reactive hyperemia. The technique allows the study of the level of vascular impairment and probably quantifying the level of endothelial dysfunction at peripheral arteries. The experiment was performed on two cohorts of 13 and 15 patients and was compared to strain gauge plethysmography (SGP) which is considered as gold standard. Afterward, we characterized endothelial reaction during reactive hyperemia through blood flow variations by modeling the hyperemic curve. Preliminary studies have shown that the hyperemic response generally adopts a bimodal form. The first peak was attributed to myogenic reaction that is endothelial independent and the second one to local endothelial cells reaction. The quantification of the two hyperemic response components makes it possible to calculate an index of ‘health’ for local endothelial cells, named ηfactor. The results showed a strong correlation (r = 0.91) of blood flow measurements between the developed method and the gold standard. We concluded that NIRS is a precise technique for non-invasive measurement of blood flow. Moreover, we found a high repeatability (ICC = 0.9313) of the ηfactor in repeated measurements indicating its robustness. Nonetheless, more studies are required to validate the diagnosis value of the defined factor. Key words: reactive hyperemia, myogenic response, endothelial dependent vasodilatation, nitric oxide, atherosclerosis, near infrared spectroscopy (NIRS)

Tese(doutorado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2011. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-06-23T16:27:42Z No. of bitstreams: 1 tese corrigida marcio figueiredo.pdf: 4782449 bytes, checksum: df5bb424fe5c9736a80fdc4a63db03a1 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-07-27T20:22:46Z (GMT) No. of bitstreams: 1 tese corrigida marcio figueiredo.pdf: 4782449 bytes, checksum: df5bb424fe5c9736a80fdc4a63db03a1 (MD5) / Made available in DSpace on 2012-07-27T20:22:46Z (GMT). No. of bitstreams: 1 tese corrigida marcio figueiredo.pdf: 4782449 bytes, checksum: df5bb424fe5c9736a80fdc4a63db03a1 (MD5) Previous issue date: 2011 / A aquicultura tem crescido significativamente nas últimas décadas devido ao aumento da demanda de pescado no mundo e à estagnação do setor pesqueiro. Porém, este crescimento depende do desenvolvimento de novos pacotes tecnológicos que visem o aumento da produtividade. Uma alternativa é a manipulação genética (transgenia), sendo que o hormônio do crescimento (GH) tem sido o principal alvo das pesquisas com peixes transgênicos. Entretanto, está comprovado que o excesso de GH acarreta uma série de efeitos adversos devido a sua ação pleiotrópica. A ativação do eixo somatotrófico de forma tecido-específica e independente do excesso de hormônio circulante pode contornar estes problemas. Neste contexto, o objetivo desta tese foi superexpressar o gene do receptor do GH (GHR) no tecido muscular esquelético do zebrafish (Danio rerio) e estudar os efeitos desta manipulação sobre os mecanismos envolvidos na regulação gênica do crescimento muscular. A linhagem transgênica estável obtida expressa o GHR especificamente no tecido muscular 100 vezes mais do que os não transgênicos. Estes transgênicos não apresentaram aumento significativo no crescimento, provavelmente devido à queda na expressão do fator de crescimento tipo insulina I (IGF-I). Esta queda foi, provavelmente, relacionada à ação dos principais moduladores da sinalização do GH (SOCS1 e 3), os quais apresentaram-se aumentados nos transgênicos. Ainda, foi observada uma queda na expressão das principais proteínas musculares estruturais (Acta1, myhc4 e mylz2), o que explica a ausência de hipertrofia nos transgênicos. Por outro lado, o aumento na expressão dos principais fatores reguladores miogênicos (myod, myf5 e myog) explica a hiperplasia observada nas análises histológicas. Para verificar como a superexpressão do GHR ativou a transcrição dos fatores reguladores miogênicos (MRFs) e, por consequência a hiperplasia, foram estudados os possíveis mecanismos envolvidos neste processo. Dentre estes, tanto a via proliferativa (MEK/ERK) quanto à via relacionada com a síntese protéica (PI3K/Akt), não tiveram alteração na expressão de seus genes. Entretanto, foi observado aumento na expressão das proteínas de transporte para o núcleo (importinas 1, 3 e 1), podendo-se concluir que a ativação dos MRFs está relacionada ao transporte do GHR para o núcleo das células musculares. Desta forma, pode se concluir que hiperplasia e hipertrofia seguem duas vias de sinalização intracelular distintas, ambas desencadeadas pelo GH, mas reguladas por mecanismos diferentes. / Aquiculture practice has been significantly increasing during the last decades due to the fish rising demand and to fishery activity stagnation. However, such increase depends on new technological packages development aiming to productivity rises. Genetic manipulation is an alternative, once growth hormone (GH) has been the main target on transgenic fish researches. Nevertheless, it has been proved that GH excess leads to many adverse effects due to its pleiotropic action. The somatotropic axis activation in a tissue-specific manner and independent on the circulating hormone excess may bypass these problems. Following these ideas, the present thesis objective was overexpressing GH receptor’s gene (GHR), in zebrafish (Danio rerio) skeletal muscular tissue, and studying such manipulation effects over the mechanisms involved in muscular growth gene regulation. The stable transgenic lineage obtained expresses GHR, specifically in muscular tissue, 100 times more than non-transgenic. These transgenic did not present significant growth, possibly due to a gene expression fall in insulin-like growth factor I (IGF-I). The mentioned fall is, probably, related to GH main signaling modulators (SOCS1 and 3) action, which were increased in transgenic. Also, a gene expression fall from the main structural muscle proteins (Acta1, myhc4 and mylz2) was observed, explaining the transgenic hypertrophy absence. However, the main myogenic regulatory factors (myod, myf5 and myog) expression rising explains the observed hyperplasia in histological analysis. Intending to verify how GHR overexpression has activated the myogenic regulatory factors (MRFs) transcription and, consequently, the hyperplasia, the mechanisms possibly involved in this process were studied. Among these, even the proliferative pathway (MEK/ERK) or the pathway related to protein synthesis (PI3K/Akt), did not presented gene expression altering. However, a gene expression rise in transporting proteins into nucleus (importins 1, 3 and 1) was observed, which may be understood as a correlation between MRFs activation and GHR transport into muscular cell’s nucleus. Therefore, it may be understood that hyperplasia and hypertrophy follow two distinct intracellular signaling pathways, both triggered by GH, but regulated by different mechanisms. These data may be important for aquiculture new transgenic lineages development.

Dissertação(mestrado)- Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2009. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-08-10T13:50:16Z No. of bitstreams: 1 Rafael.pdf: 548290 bytes, checksum: 93681ab1550a68d8844eefffd0bf0b49 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-09-18T02:09:25Z (GMT) No. of bitstreams: 1 Rafael.pdf: 548290 bytes, checksum: 93681ab1550a68d8844eefffd0bf0b49 (MD5) / Made available in DSpace on 2012-09-18T02:09:25Z (GMT). No. of bitstreams: 1 Rafael.pdf: 548290 bytes, checksum: 93681ab1550a68d8844eefffd0bf0b49 (MD5) Previous issue date: 2009 / O hormônio do crescimento (GH) é produzido e secretado pela adeno-hipófise tendo como efeito principal promover o crescimento somático em vertebrados. No presente estudo foi analisada a morfometria do crescimento, estrutura do tecido muscular e expressão de fatores miogênicos em indivíduos machos e fêmeas da linhagem F0104 de zebrafish transgênico para o GH. Os índices morfométricos sugerem que o excesso de GH circulante está promovendo uma antecipação na idade de maturação sexual. Também, foi observado um menor fator de condição nos transgênicos de ambos os sexos (P<0,05) e uma alteração nos padrões morfométricos ao longo do tempo evidente nos machos transgênicos. As análises multivariadas demonstraram dois fenótipos distintos de machos transgênicos. O primeiro assemelha-se às fêmeas transgênicas (tamanho grande e baixo fator de condição), e o segundo aos machos não transgênicos (menor tamanho e baixo fator de condição). Este padrão de crescimento heterogêneo nos machos transgênicos pode ser explicado pela alteração do perfil de secreção do GH associado à variabilidade genética individual na resposta ao excesso de GH circulante. As análises histológicas demostraram que os transgênicos apresentam uma hipertrofia muscular acentuada quando comparados com os não transgênicos, sendo as fêmeas transgênicas mais hipertróficas do que os machos transgênicos. A expressão dos genes relacionados com o crescimento muscular mostrou que a hipertrofia muscular observada nos transgênicos é independente do fator de crescimento tipo insulina I (IGF-I). Adicionalmente, nos machos transgênicos foi observada uma indução significativa na expressão da miogenina, indicando que esta proteína pode estar mediando, pelo menos em parte, o crescimento hipertrófico neste grupo. A expressão gênica também mostrou uma indução da a-actina somente em machos, independentemente da transgenia. Entretanto, não foi observada alteração no teor de proteínas totais de músculo. Dentro do contexto dos resultados obtidos no presente estudo, ficou evidente que o excesso de GH nos peixes transgênicos da linhagem F0104 provavelmente esteja promovendo uma maturação sexual precoce, uma hipertrofia muscular independente de IGF-I, e um crescimento heterogêneo em machos transgênicos devido à alteração do padrão de secreção do hormônio como efeito da expressão constitutiva do transgene. Este modelo é uma ferramenta interessante para o estudo de peixes com crescimento limitado. / Growth hormone (GH) is produced and released by the adenohypohysis being its main role to promote vertebrate somatic growth. The present study analyzed growth morphometrics, muscular tissue structure and myogenic factors expression in males and females from F0104 transgenic zebrafish lineage for GH. Morphometric indexes suggest that systemic GH excess is promoting an early sexual maturation. It was also observed a minor conditional factor in both sexes of transgenic group (P<0.05), and an evident time-course male altering in morphometric patterns. The first is similar to transgenic females (big size and low condiction factor) and the second to non-transgenic males (smaller size and low condiction factor). This heterogeneous male growth pattern may be explained by the altering of the GH secretion profile associated to individual genetic variability in answer to systemic GH excess. Histological analysis demonstrated that transgenic presented an enhanced muscle hypertrophy when compared to non-transgenic, being transgenic females more hypertrophic than transgenic males. Gene expression related to muscle growth revealed that transgenic hypertrophy observed is independent from insulin-like growth factor I (IGF-I). In addition, transgenic males had a significantly myogenin gene expression induction indicating that, at least partially, this protein may be mediating hypertrophic growth in this group. It was also shown an induction in males of the a-actin gene independently from transgenesis. However, there were no diferences in total protein content from the muscle. According the data presented in this study, it was evident that GH excess in F0104 transgenic fish lineage is probably promoting an early sexual maturation, a muscle hypertrophy independent from IGFI, and a heterogeneous transgenic males growth due to hormone secretion pattern altering as an effect of the transgene constitutive expression. This model is an interesting tool for the study of fishes with limited growth.

Orientador: Maeli Dal Pai Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T01:12:18Z (GMT). No. of bitstreams: 1 Souza_RodrigoWagnerAlves_M.pdf: 2186081 bytes, checksum: 2a1578159471f249151f3b90ca0b76fb (MD5) Previous issue date: 2010 / Resumo: O treinamento físico pode promover adaptações benéficas ao músculo esquelético. Entretanto, o treinamento de alta intensidade associado com um tempo insuficiente de recuperação, similar às condições de sobretreinamento, pode ocasionar efeitos prejudiciais. Os fatores reguladores miogênicos (MRFs) e o fator de crescimento IGF-1 são importantes reguladores da massa muscular no treinamento físico. Neste contexto, testamos a hipótese que o treinamento de alta intensidade com curto tempo de recuperação, poderia influenciar a morfologia, as isoformas da cadeia pesada de miosina (MHC), e a expressão dos MRFs MyoD e Miogenina e do IGF-1, no músculo esquelético de ratos. Ratos Wistar machos (200-250g) foram divididos em 4 grupos: treinado 8 semanas (T8), controle 8 semanas (C8), treinado 12 semanas (T12) e controle 12 semanas (C12). Os grupos T8 e T12 realizaram um programa de treinamento resistido de alta intensidade (5 dias/semana), envolvendo sessões de saltos em uma cuba contendo água. Ao término de cada período, os animais foram sacrificados e o músculo plantar retirado e submetido às análises morfológica e histoquímica, análises das MHCs e expressão gênica da MyoD, Miogenina e IGF-1. Do início ao final do experimento todos os grupos aumentaram o peso corporal, no entanto, o grupo T12 foi estatisticamente menor em relação ao C12. Com relação à área de secção transversal, observou-se uma redução das fibras IIC e IIAD no grupo T8 e IIA e IID no grupo T12 em relação aos seus controles. O grupo treinado por 12 semanas apresentou um aumento da frequência das fibras IIBD e redução nas frequências das fibras I, IIA e IID, em relação ao grupo controle; esses dados ainda foram corroborados pela redução das isoformas MHCI e MHCIIa e aumento da MHCIIb. A MHCIId não mostrou diferença significativa. A expressão gênica do grupo T12 apontou uma diminuição da MyoD e um aumento do IGF-1 comparado com o grupo C12; já, a expressão da Miogenina foi semelhante entre os grupos. Estes dados mostram que o modelo utilizado, semelhante às condições do sobretreinamento, promoveu a atrofia muscular e a transição das fibras musculares para uma atividade contrátil mais rápida. Estes fatos podem estar associados a uma menor atividade das células satélites. Em adição, o aumento da expressão do IGF-1, decorrente do treinamento, pode ter ocorrido na tentativa de prevenir o processo atrófico. / Abstract: Physical training can promote beneficial changes in skeletal muscle. However, the high-intensity resistance training associated with insufficient recovery time may cause harmful effects. Myogenic regulatory factors (MRFs) and the growth factor IGF-1 are important mediators of muscle mass during physical training. In this context, we tested the hypothesis that high-intensity resistance training with short recovery time, similar to overtraining conditions, could influence the morphology, the myosin heavy chain (MHC) isoforms and the expression of MRFs MyoD and myogenin, and IGF-1 in skeletal muscle of rats. Male Wistar rats (200-250 g) were divided into 4 groups: trained 8 weeks (T8), control 8 weeks (C8), trained 12 weeks (T12) and control 12 weeks (C12). T8 and T12 groups were subjected to a high-intesnsity resistance training program (5 days/week), involving jumps sessions into water, carrying progressive overload equivalent to percentage of body weight. At the end of each period the animals were sacrificed and the plantaris muscles were removed and submited to morphological and histochemical analysis, myosin heavy chain (MHC) analysis and the gene expression of MyoD, Myogenin and IGF-1. From beginning to end of the experiment all groups increased body weight, however, in T12 body weight was lower compared to the C12. Regarding the cross-sectional area, there was a significant reduction of the IIC fibers and IIAD in T8 group and IIA and IID in T12 compared to their controls. The group trained by 12 weeks showed an increase in the IIBD, accompanied by a reduction in the I, IIA and IID muscle fibers frequency, compared to control group; these data have been corroborated by the reduction of MHCI and MHCIIa isoforms and increased of MHCIIb isoform. The MHCIId showed no significant differences. The gene expression of the T12 group showed a decrease in MyoD and an increase in IGF-1 compared with the C12 group; already, the expression of Myogenin was similar between groups. These data show that the model used, similar to the conditions of overtraining, promoted muscular atrophy and muscle fiber transition to a faster contractile activity. These facts may be associated with a lower activity of satellite cells. In addition, increased expression of IGF-1, due to training, may have occurred in an attempt to prevent the atrophic process. / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

Le gène Notch3 code pour un récepteur transmembranaire hétérodimérique exprimé principalement dans les cellules musculaires lisses des petites artères. Les travaux de ces dernières années ont montré que le récepteur Notch3 joue un rôle clé dans la physiologie et la pathologie des petites artères. Chez la souris, Notch3 est requis pour l’intégrité structurale et fonctionnelle des artères de résistance en contrôlant l’identité artérielle, la maturation postnatale des cellules musculaires lisses et le tonus myogénique des artères de résistance. Chez l’Homme, les maladies des petites artères cérébrales (MPAC) regroupent un ensemble hétérogène de maladies parmi lesquelles un petit pourcentage, probablement encore sous-estimée, est héréditaire. A ce jour, très peu de gènes responsables de formes familiales de MPAC ont été identifiés. CADASIL est la forme familiale la plus fréquente de MPAC causée par des mutations du gène NOTCH3. Il s’agit de mutations extrêmement stéréotypées siégeant dans les répétitions EGF qui constituent le domaine extracellulaire de Notch3. Les résultats du laboratoire suggèrent fortement que l’effet pathogène de ces mutations résulte de l’acquisition par le récepteur muté d’une nouvelle fonction. Les deux objectifs de ce travail ont été : 1°) Tester l’hypothèse qu’il existe des maladies des petites artères cérébrales causées directement par une modification de l’activité du récepteur Notch3 2°) Identifier les effecteurs du récepteur Notch3 dans le contexte du développement et de la maturation des artères cérébrales Nous avons identifié chez une patiente présentant une MPAC distincte de CADASIL une nouvelle mutation siégeant dans le domaine d’hétérodimérisation du récepteur Notch3. In vitro, la mutation L1515P induit une activation ligand indépendante du récepteur Notch3. L’analyse biochimique suggère que cette activation est causée par une déstabilisation du domaine d’hétérodimérisation de Notch3.Nous avons réalisé une analyse du transcriptome des artères caudales de souris Notch3-/- et Notch3+/+. Cette analyse a permis d’identifier un groupe de 17 gènes régulés par Notch3 dans l’artère caudale ou les artères cérébrales. L’invalidation du facteur de transcription CSL/RBPJK dans les cellules musculaires lisses, pendant la période postnatale immédiate, phénocopie les altérations structurales et moléculaires observées chez les souris Notch3-/-. L’administration chez la souris d’un inhibiteur pharmacologique de la voie Notch a permis d’identifier 6 gènes (Grip2, Nrip2, Kv1.5, Pgam2, Susd5, Xirp1), en plus de Notch3, dont l’expression dans les artères cérébrales est rapidement diminuée par ce traitement. Nous avons ensuite concentré nos efforts sur le gène Grip2 dont l’expression était la plus fortement diminuée dans les différents modèles d’inactivation de la voie Notch. Grip2 était jusqu’alors connu pour son interaction avec les récepteurs au glutamate dans les neurones. Nous avons montré que Grip2 était également exprimé dans les cellules musculaires lisses vasculaires et identifié une isoforme vasculaire régulée spécifiquement par Notch3/CSL/RBPJK. L’analyse des souris Grip2neo/neo, exprimant une protéine Grip2 tronquée dans sa partie N-terminale, a révélé une atteinte sélective du tonus myogénique des artères cérébrales.En conclusion, nous avons démontré l’existence d’une mutation activatrice de NOTCH3 associée à une MPAC chez l’Homme. Nos résultats indiquent que dans le contexte de la maturation des artères cérébrales, la fonction de Notch3 est médiée par le facteur de transcription CSL/RBPJK dans les cellules musculaires lisses durant la période postnatale immédiate. Nous avons identifié plusieurs nouveaux effecteurs potentiels de Notch3 et validé l’un d’entre eux, Grip2, pour son implication dans les réponses myogéniques des artères cérébrales. Nous proposons que des mutations dans les gènes codant pour ces effecteurs puissent rendre compte de certaines formes monogéniques de MPAC. / Notch3 encodes a transmembrane receptor primarily expressed in arterial smooth muscle cells. Human and mouse genetics studies demonstrated that Notch3 is a key player in physiology and diseases of small vessels. Studies in mice revealed that Notch3 is required to generate functional arteries in regulating arterial differentiation, maturation of vascular smooth muscle cells and myogenic tone. Cerebral Autosomal Dominant Arteriopathy with Subcortical infarcts and Leukoencephalopathy (CADASIL) is the most frequent hereditary small vessels disease in human adults caused by NOTCH3 mutations. Pathogenic mutations lead to an odd number of cysteine residues within the NOTCH3 extracellular domain. Data from the laboratory suggest a model that invokes novel pathogenic roles from the mutant NOTCH3 protein. The main goals of this work are: 1°) To determine if there is small vessels disease caused by modification of Notch3 activity 2°) To identify Notch3 effectors involved in development and maturation of cerebral arteries We identified a novel heterozygous missense mutation (L1515P) in the heterodimerization domain of NOTCH3 in a patient with cerebral small vessel distinct from CADASIL. In vitro analysis showed that the L1515P mutant exhibits increased canonical NOTCH3 signaling in a ligand-independent manner. Biochemical analysis suggests that the mutation renders NOTCH3 hyperactive through destabilization of the heterodimer. Transcriptome analysis using tail arteries of Notch3-/- and Notch3+/+ mice identified a core set of 17 novel Notch3-regulated genes confirmed in tail or brain arteries. Postnatal deletion of RBP-Jκ in smooth muscle cells recapitulated the structural, functional, and molecular defects of brain arteries induced by Notch3 deficiency. Transient in vivo blockade of the Notch pathway with γ-secretase inhibitors uncovered, in addition to Notch3, 6 immediate responders, including the voltage-gated potassium channel Kv1.5, which opposes to myogenic constriction of brain arteries, and the glutamate receptor-interacting protein-2, with no previously established role in the cerebrovasculature. We identified a vascular smooth muscle cell isoform of Grip2. We showed that Notch3-RBP-Jκ specifically regulates this isoform. Finally, we found that cerebral arteries of glutamate receptor-interacting protein-2 mutant mice, which express an N-terminally truncated glutamate receptor-interacting protein-2, exhibited selective attenuation of pressure-induced contraction. In conclusion, we have demonstrated the existence of a NOTCH3 activating mutation associated with small vessels disease in human. Our results show that, in the context of cerebral arteries maturation, Notch3 functions are mediated by CSL/RBPJK transcription factor. We have identified several new Notch3 effectors and validated Grip2 as a novel regulator of myogenic tone in cerebral arteries. One can expect that mutations in these Notch3-regulated genes could be responsible of some monogenic form of small vessel diseases of the brain.