Centre d'Information et de documentation du CRA Rhône-Alpes
CRA
Informations pratiques
-
Adresse
Centre d'information et de documentation
du CRA Rhône-Alpes
Centre Hospitalier le Vinatier
bât 211
95, Bd Pinel
69678 Bron CedexHoraires
Lundi au Vendredi
9h00-12h00 13h30-16h00Contact
Tél: +33(0)4 37 91 54 65
Mail
Fax: +33(0)4 37 91 54 37
-
Résultat de la recherche
2 recherche sur le mot-clé 'Electron microscopy'
Affiner la recherche Générer le flux rss de la recherche
Partager le résultat de cette recherche Faire une suggestion
Altered synaptic ultrastructure in the prefrontal cortex of Shank3-deficient rats / Sarah JACOT-DESCOMBES in Molecular Autism, 11 (2020)
[article]
Titre : Altered synaptic ultrastructure in the prefrontal cortex of Shank3-deficient rats Type de document : Texte imprimé et/ou numérique Auteurs : Sarah JACOT-DESCOMBES, Auteur ; Neha U. KESHAV, Auteur ; Dara L. DICKSTEIN, Auteur ; Bridget WICINSKI, Auteur ; William G. M. JANSSEN, Auteur ; Liam L. HIESTER, Auteur ; Edward K. SARFO, Auteur ; Tahia WARDA, Auteur ; Matthew M. FAM, Auteur ; Hala HARONY-NICOLAS, Auteur ; Joseph D. BUXBAUM, Auteur ; Patrick R. HOF, Auteur ; Merina VARGHESE, Auteur Langues : Anglais (eng) Mots-clés : Autism spectrum disorder Electron microscopy Phelan–McDermid syndrome Synapse morphology Index. décimale : PER Périodiques Résumé : BACKGROUND: Deletion or mutations of SHANK3 lead to Phelan-McDermid syndrome and monogenic forms of autism spectrum disorder (ASD). SHANK3 encodes its eponymous scaffolding protein at excitatory glutamatergic synapses. Altered morphology of dendrites and spines in the hippocampus, cerebellum, and striatum have been associated with behavioral impairments in Shank3-deficient animal models. Given the attentional deficit in these animals, our study explored whether deficiency of Shank3 in a rat model alters neuron morphology and synaptic ultrastructure in the medial prefrontal cortex (mPFC). METHODS: We assessed dendrite and spine morphology and spine density in mPFC layer III neurons in Shank3-homozygous knockout (Shank3-KO), heterozygous (Shank3-Het), and wild-type (WT) rats. We used electron microscopy to determine the density of asymmetric synapses in mPFC layer III excitatory neurons in these rats. We measured postsynaptic density (PSD) length, PSD area, and head diameter (HD) of spines at these synapses. RESULTS: Basal dendritic morphology was similar among the three genotypes. Spine density and morphology were comparable, but more thin and mushroom spines had larger head volumes in Shank3-Het compared to WT and Shank3-KO. All three groups had comparable synapse density and PSD length. Spine HD of total and non-perforated synapses in Shank3-Het rats, but not Shank3-KO rats, was significantly larger than in WT rats. The total and non-perforated PSD area was significantly larger in Shank3-Het rats compared to Shank3-KO rats. These findings represent preliminary evidence for synaptic ultrastructural alterations in the mPFC of rats that lack one copy of Shank3 and mimic the heterozygous loss of SHANK3 in Phelan-McDermid syndrome. LIMITATIONS: The Shank3 deletion in the rat model we used does not affect all isoforms of the protein and would only model the effect of mutations resulting in loss of the N-terminus of the protein. Given the higher prevalence of ASD in males, the ultrastructural study focused only on synaptic structure in male Shank3-deficient rats. CONCLUSIONS: We observed increased HD and PSD area in Shank3-Het rats. These observations suggest the occurrence of altered synaptic ultrastructure in this animal model, further pointing to a key role of defective expression of the Shank3 protein in ASD and Phelan-McDermid syndrome. En ligne : http://dx.doi.org/10.1186/s13229-020-00393-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=438
in Molecular Autism > 11 (2020)[article] Altered synaptic ultrastructure in the prefrontal cortex of Shank3-deficient rats [Texte imprimé et/ou numérique] / Sarah JACOT-DESCOMBES, Auteur ; Neha U. KESHAV, Auteur ; Dara L. DICKSTEIN, Auteur ; Bridget WICINSKI, Auteur ; William G. M. JANSSEN, Auteur ; Liam L. HIESTER, Auteur ; Edward K. SARFO, Auteur ; Tahia WARDA, Auteur ; Matthew M. FAM, Auteur ; Hala HARONY-NICOLAS, Auteur ; Joseph D. BUXBAUM, Auteur ; Patrick R. HOF, Auteur ; Merina VARGHESE, Auteur.
Langues : Anglais (eng)
in Molecular Autism > 11 (2020)
Mots-clés : Autism spectrum disorder Electron microscopy Phelan–McDermid syndrome Synapse morphology Index. décimale : PER Périodiques Résumé : BACKGROUND: Deletion or mutations of SHANK3 lead to Phelan-McDermid syndrome and monogenic forms of autism spectrum disorder (ASD). SHANK3 encodes its eponymous scaffolding protein at excitatory glutamatergic synapses. Altered morphology of dendrites and spines in the hippocampus, cerebellum, and striatum have been associated with behavioral impairments in Shank3-deficient animal models. Given the attentional deficit in these animals, our study explored whether deficiency of Shank3 in a rat model alters neuron morphology and synaptic ultrastructure in the medial prefrontal cortex (mPFC). METHODS: We assessed dendrite and spine morphology and spine density in mPFC layer III neurons in Shank3-homozygous knockout (Shank3-KO), heterozygous (Shank3-Het), and wild-type (WT) rats. We used electron microscopy to determine the density of asymmetric synapses in mPFC layer III excitatory neurons in these rats. We measured postsynaptic density (PSD) length, PSD area, and head diameter (HD) of spines at these synapses. RESULTS: Basal dendritic morphology was similar among the three genotypes. Spine density and morphology were comparable, but more thin and mushroom spines had larger head volumes in Shank3-Het compared to WT and Shank3-KO. All three groups had comparable synapse density and PSD length. Spine HD of total and non-perforated synapses in Shank3-Het rats, but not Shank3-KO rats, was significantly larger than in WT rats. The total and non-perforated PSD area was significantly larger in Shank3-Het rats compared to Shank3-KO rats. These findings represent preliminary evidence for synaptic ultrastructural alterations in the mPFC of rats that lack one copy of Shank3 and mimic the heterozygous loss of SHANK3 in Phelan-McDermid syndrome. LIMITATIONS: The Shank3 deletion in the rat model we used does not affect all isoforms of the protein and would only model the effect of mutations resulting in loss of the N-terminus of the protein. Given the higher prevalence of ASD in males, the ultrastructural study focused only on synaptic structure in male Shank3-deficient rats. CONCLUSIONS: We observed increased HD and PSD area in Shank3-Het rats. These observations suggest the occurrence of altered synaptic ultrastructure in this animal model, further pointing to a key role of defective expression of the Shank3 protein in ASD and Phelan-McDermid syndrome. En ligne : http://dx.doi.org/10.1186/s13229-020-00393-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=438 Synaptic vesicle dynamic changes in a model of fragile X / Jantine A.C. BROEK in Molecular Autism, 7 (2016)
[article]
Titre : Synaptic vesicle dynamic changes in a model of fragile X Type de document : Texte imprimé et/ou numérique Auteurs : Jantine A.C. BROEK, Auteur ; Z. LIN, Auteur ; H. M. DE GRUITER, Auteur ; H. VAN 'T SPIJKER, Auteur ; E. D. HAASDIJK, Auteur ; David COX, Auteur ; S. OZCAN, Auteur ; G. W. A. VAN CAPPELLEN, Auteur ; A. B. HOUTSMULLER, Auteur ; R. WILLEMSEN, Auteur ; C. I. DE ZEEUW, Auteur ; S. BAHN, Auteur Article en page(s) : 17p. Langues : Anglais (eng) Mots-clés : Animals Animals, Congenic Cells, Cultured Cerebellum/pathology/physiopathology Fluorescent Dyes Fragile X Mental Retardation Protein/genetics/physiology Fragile X Syndrome/genetics/metabolism/physiopathology Hippocampus/pathology/physiopathology Intravital Microscopy Male Mass Spectrometry/methods Mice Mice, Inbred C57BL Mice, Knockout Mice, Neurologic Mutants Microscopy, Electron Models, Animal Nerve Tissue Proteins/analysis Presynaptic Terminals/secretion Proteome Purkinje Cells/physiology/ultrastructure Pyridinium Compounds Quaternary Ammonium Compounds Signal Transduction Synaptic Transmission Synaptic Vesicles/metabolism Synaptosomes/metabolism Electron microscopy Fragile X syndrome (FXS) Mass spectrometry (MS) Quantitative live-cell imaging Index. décimale : PER Périodiques Résumé : BACKGROUND: Fragile X syndrome (FXS) is a single-gene disorder that is the most common heritable cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorders (ASD). FXS is caused by an expansion of trinucleotide repeats in the promoter region of the fragile X mental retardation gene (Fmr1). This leads to a lack of fragile X mental retardation protein (FMRP), which regulates translation of a wide range of messenger RNAs (mRNAs). The extent of expression level alterations of synaptic proteins affected by FMRP loss and their consequences on synaptic dynamics in FXS has not been fully investigated. METHODS: Here, we used an Fmr1 knockout (KO) mouse model to investigate the molecular mechanisms underlying FXS by monitoring protein expression changes using shotgun label-free liquid-chromatography mass spectrometry (LC-MS(E)) in brain tissue and synaptosome fractions. FXS-associated candidate proteins were validated using selected reaction monitoring (SRM) in synaptosome fractions for targeted protein quantification. Furthermore, functional alterations in synaptic release and dynamics were evaluated using live-cell imaging, and interpretation of synaptic dynamics differences was investigated using electron microscopy. RESULTS: Key findings relate to altered levels of proteins involved in GABA-signalling, especially in the cerebellum. Further exploration using microscopy studies found reduced synaptic vesicle unloading of hippocampal neurons and increased vesicle unloading in cerebellar neurons, which suggests a general decrease of synaptic transmission. CONCLUSIONS: Our findings suggest that FMRP is a regulator of synaptic vesicle dynamics, which supports the role of FMRP in presynaptic functions. Taken together, these studies provide novel insights into the molecular changes associated with FXS. En ligne : http://dx.doi.org/10.1186/s13229-016-0080-1 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=328
in Molecular Autism > 7 (2016) . - 17p.[article] Synaptic vesicle dynamic changes in a model of fragile X [Texte imprimé et/ou numérique] / Jantine A.C. BROEK, Auteur ; Z. LIN, Auteur ; H. M. DE GRUITER, Auteur ; H. VAN 'T SPIJKER, Auteur ; E. D. HAASDIJK, Auteur ; David COX, Auteur ; S. OZCAN, Auteur ; G. W. A. VAN CAPPELLEN, Auteur ; A. B. HOUTSMULLER, Auteur ; R. WILLEMSEN, Auteur ; C. I. DE ZEEUW, Auteur ; S. BAHN, Auteur . - 17p.
Langues : Anglais (eng)
in Molecular Autism > 7 (2016) . - 17p.
Mots-clés : Animals Animals, Congenic Cells, Cultured Cerebellum/pathology/physiopathology Fluorescent Dyes Fragile X Mental Retardation Protein/genetics/physiology Fragile X Syndrome/genetics/metabolism/physiopathology Hippocampus/pathology/physiopathology Intravital Microscopy Male Mass Spectrometry/methods Mice Mice, Inbred C57BL Mice, Knockout Mice, Neurologic Mutants Microscopy, Electron Models, Animal Nerve Tissue Proteins/analysis Presynaptic Terminals/secretion Proteome Purkinje Cells/physiology/ultrastructure Pyridinium Compounds Quaternary Ammonium Compounds Signal Transduction Synaptic Transmission Synaptic Vesicles/metabolism Synaptosomes/metabolism Electron microscopy Fragile X syndrome (FXS) Mass spectrometry (MS) Quantitative live-cell imaging Index. décimale : PER Périodiques Résumé : BACKGROUND: Fragile X syndrome (FXS) is a single-gene disorder that is the most common heritable cause of intellectual disability and the most frequent monogenic cause of autism spectrum disorders (ASD). FXS is caused by an expansion of trinucleotide repeats in the promoter region of the fragile X mental retardation gene (Fmr1). This leads to a lack of fragile X mental retardation protein (FMRP), which regulates translation of a wide range of messenger RNAs (mRNAs). The extent of expression level alterations of synaptic proteins affected by FMRP loss and their consequences on synaptic dynamics in FXS has not been fully investigated. METHODS: Here, we used an Fmr1 knockout (KO) mouse model to investigate the molecular mechanisms underlying FXS by monitoring protein expression changes using shotgun label-free liquid-chromatography mass spectrometry (LC-MS(E)) in brain tissue and synaptosome fractions. FXS-associated candidate proteins were validated using selected reaction monitoring (SRM) in synaptosome fractions for targeted protein quantification. Furthermore, functional alterations in synaptic release and dynamics were evaluated using live-cell imaging, and interpretation of synaptic dynamics differences was investigated using electron microscopy. RESULTS: Key findings relate to altered levels of proteins involved in GABA-signalling, especially in the cerebellum. Further exploration using microscopy studies found reduced synaptic vesicle unloading of hippocampal neurons and increased vesicle unloading in cerebellar neurons, which suggests a general decrease of synaptic transmission. CONCLUSIONS: Our findings suggest that FMRP is a regulator of synaptic vesicle dynamics, which supports the role of FMRP in presynaptic functions. Taken together, these studies provide novel insights into the molecular changes associated with FXS. En ligne : http://dx.doi.org/10.1186/s13229-016-0080-1 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=328