Development of Mice with Brain-Specific Deletion of Floxed Glud1 (Glutamate Dehydrogenase 1) Using Cre Recombinase Driven by the Nestin Promoter

In the brain, Glud1-encoded glutamate dehydrogenase plays a major role in the recycling of the neurotransmitter glutamate. We recently reported a new model of brain-specific Glud1 null mice (Cns-Glud1 −/−) lacking glutamate dehydrogenase in the central nervous system. Cns-Glud1 −/− mice exhibit reduced astrocytic glutamate breakdown and redirection of glutamate pathways without altering synaptic transmission. Cns-Glud1 −/− mice were generated using LoxP and Nestin-Cre technology. Nestin-Cre mice are widely used to investigate gene deletion in the central nervous system. However, the Nes-Cre transgene itself was reported to induce a phenotype related to body weight gain. Here, we review the potential side-effects of Nes-Cre and analysed Cns-Glud1 −/− body weight gain. Overall, Nestin-Cre mice may exhibit transient and moderate growth retardation during the few weeks immediately following weaning. Pending appropriate controls and homogenization of the genetic background, Nestin-Cre technology is a valuable tool enabling disruption of genes of interest in the central nervous system

Clinical, Neuroimaging, and Genetic Features of the Patients with L-2-Hydroxyglutaric Aciduria

Aim:L-2-hydroxyglutaric aciduria (L2HGA) is a rare autosomal recessive encephalopathy caused by mutations in the L-2-hydroxyglutarate dehydrogenase gene.Materials and Methods:Here we discuss the clinical and molecular characteristics in patients with L2HGA.Results:There were eight patients with L2HGA. Their median age was 16 (9.5-37) years. Five of them were female and three of them were male. The main symptoms of the patients were psychomotor retardation (8/8), cerebellar ataxia (5/8), extrapyramidal symptoms (7/8) and seizures (4/8). All patients had behavioral problems. Elevated urinary L-2-hydroxy (L-2-OH) glutaric acid was detected and the median level of urine L-2-OH glutaric acid at diagnosis was 146 (60-1460 nmol/mol creat). Characteristic magnetic resonance imaging findings including subcortical cerebral white matter abnormalities with T2 hyperintensities of the dentate nucleus, globus pallidus and putamen were detected. Two patients had homozygous R335X, two patients had homozygous R282Q, two patients had homozygous R302L and one patient had compound heterozygous P302L/A64T mutation in L-2-hydroxyglutarate dehydrogenase (L2HGDH) gene.Conclusion:Because of the slow progression of the disease, the diagnosis of the patients is usually belated. L2HGA must be considered in the differential diagnosis based on clinical findings and specific findings in cranial magnetic resonance imaging. In our study, one of our patients has a novel mutation

Exploring Functional β-Cell Heterogeneity In Vivo Using PSA-NCAM as a Specific Marker

BACKGROUND:The mass of pancreatic beta-cells varies according to increases in insulin demand. It is hypothesized that functionally heterogeneous beta-cell subpopulations take part in this process. Here we characterized two functionally distinct groups of beta-cells and investigated their physiological relevance in increased insulin demand conditions in rats. METHODS:Two rat beta-cell populations were sorted by FACS according to their PSA-NCAM surface expression, i.e. beta(high) and beta(low)-cells. Insulin release, Ca(2+) movements, ATP and cAMP contents in response to various secretagogues were analyzed. Gene expression profiles and exocytosis machinery were also investigated. In a second part, beta(high) and beta(low)-cell distribution and functionality were investigated in animal models with decreased or increased beta-cell function: the Zucker Diabetic Fatty rat and the 48 h glucose-infused rat. RESULTS:We show that beta-cells are heterogeneous for PSA-NCAM in rat pancreas. Unlike beta(low)-cells, beta(high)-cells express functional beta-cell markers and are highly responsive to various insulin secretagogues. Whereas beta(low)-cells represent the main population in diabetic pancreas, an increase in beta(high)-cells is associated with gain of function that follows sustained glucose overload. CONCLUSION:Our data show that a functional heterogeneity of beta-cells, assessed by PSA-NCAM surface expression, exists in vivo. These findings pinpoint new target populations involved in endocrine pancreas plasticity and in beta-cell defects in type 2 diabetes

Secondary Intraocular Lens Implantation in Spontaneous Crystalline Lens AbsorptionFollowing Penetrating Eye Injury: Case Report

Özellikle gençlerde travma veya inflamasyon kristalin lenste spontan absorbsiyona neden olabilir. Spontan absorbsiyon gelişmesi için geçen süre olgudan olguya değişiklik gösterir. Spontan lens absorbsiyonuna neden olan mekanizma tam olarak anlaşılamamıştır. Fakat travmatik vaka-- larda lens kapsülünde hasar oluşmasının sorumlu olabileceği düşünülmektedir. Bu olgularda ge-- lişebilecek olan üveitik veya glokomatöz reaksiyonları erken tespit etmek süreç açısından önemlidir. Bu olgu raporunda penetran göz yaralanması sonrası ankapsüle kristalin lensli bir olguda gelişen spontan absorbsiyon sonrası sekonder göziçi lens implantasyonunu sunduk.Trauma or inflammation may be the reason for spontaneous absorption of crystalline lens, especially in young people. the length of time for spontaneous absorption to take place varies. the underlying mechanism for spontaneous lens absorption is not well understood. However, in traumatic cases the injury to the lens capsule, is considered to be responsible for spontaneous lens absorption. Close follow-- up is important to timely recognize uveitis or glaucomatous reactions in regard to process. Herein we report secondary intraocular lens implantation in case with sponta-- neous absorption of the uncapsulated crystalline lens following penetrating eye injury

Hétérogénéité fonctionnelle des cellules b pancréatiques in vivo basée sur l'expression du marqueur de surface PSA-NCAM

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Development of Mice with Brain-Specific Deletion of Floxed Glud1 (Glutamate Dehydrogenase 1) Using Cre Recombinase Driven by the Nestin Promoter

In the brain, Glud1-encoded glutamate dehydrogenase plays a major role in the recycling of the neurotransmitter glutamate. We recently reported a new model of brain-specific Glud1 null mice (Cns-Glud1 (-/-)) lacking glutamate dehydrogenase in the central nervous system. Cns-Glud1 (-/-) mice exhibit reduced astrocytic glutamate breakdown and redirection of glutamate pathways without altering synaptic transmission. Cns-Glud1 (-/-) mice were generated using LoxP and Nestin-Cre technology. Nestin-Cre mice are widely used to investigate gene deletion in the central nervous system. However, the Nes-Cre transgene itself was reported to induce a phenotype related to body weight gain. Here, we review the potential side-effects of Nes-Cre and analysed Cns-Glud1 (-/-) body weight gain. Overall, Nestin-Cre mice may exhibit transient and moderate growth retardation during the few weeks immediately following weaning. Pending appropriate controls and homogenization of the genetic background, Nestin-Cre technology is a valuable tool enabling disruption of genes of interest in the central nervous system

From pancreatic islets to central nervous system, the importance of glutamate dehydrogenase for the control of energy homeostasis

Glutamate dehydrogenase (GDH) is a mitochondrial enzyme linking the Krebs cycle to the multifunctional amino acid glutamate. Thereby, GDH plays a pivotal role between carbohydrate and protein metabolisms, controlling production and consumption of the messenger molecule glutamate in neuroendocrine cells. GDH activity is under the control of several regulators, conferring to this enzyme energy-sensor property. Indeed, GDH directly depends on the provision of the co-factor NADH/NAD(+), rendering the enzyme sensitive to the redox status of the cell. Moreover, GDH is allosterically regulated by GTP and ADP. GDH is also regulated by ADP-ribosylation, mediated by a member of the energy-sensor family sirtuins, namely SIRT4. In the brain, GDH ensures the cycling of the neurotransmitter glutamate between neurons and astrocytes. GDH also controls ammonia metabolism and detoxification, mainly in the liver and kidney. In pancreatic β-cells, the importance of GDH as a key enzyme in the regulation of insulin secretion is now well established. Inhibition of GDH activity decreases insulin release, while activating mutations are associated with a hyperinsulinism syndrome. Although GDH enzyme catalyzes the same reaction in every tissue, its function regarding metabolic homeostasis varies greatly according to specific organs. In this review, we will discuss specificities of GDH regulation in neuroendocrine cells, in particular pancreatic islets and central nervous system