Convergent depression of activity-dependent bulk endocytosis in rodent models of autism spectrum disorder / Mohammed Sarfaraz NAWAZ ; Peter C. KIND ; Michael A. COUSIN in Molecular Autism, 16 (2025)  

Public ISBD [article]  inMolecular Autism > 16 (2025) . - 26 Titre : Convergent depression of activity-dependent bulk endocytosis in rodent models of autism spectrum disorder Type de document : texte imprimé Auteurs : Mohammed Sarfaraz NAWAZ, Auteur ; Peter C. KIND, Auteur ; Michael A. COUSIN, Auteur Article en page(s) : 26 Langues : Anglais (eng) Mots-clés : Animals  Endocytosis  Disease Models, Animal  Rats  Synaptic Vesicles/metabolism  Autism Spectrum Disorder/metabolism/physiopathology/genetics/pathology  Neurons/metabolism  Cells, Cultured  Exocytosis  Activity  Autism  Hippocampus  Presynapse  Rat  Vesicle  performed in accordance with the UK Animal (Scientific Procedures) Act 1986,  under Project and Personal Licence authority and were approved by the Animal  Welfare and Ethical Review Body at the University of Edinburgh (Home Office  project licence - 7008878). Similarly, procedures were conducted in accordance  with protocols approved by the Institutional Animal Ethics Committee of Institute  for Stem Cell Science and Regenerative Medicine, Bangalore. Consent for  publication: Not applicable. Competing interests: Peter Kind is an Associate  Editor for Molecular Autism. Index. décimale : PER Périodiques Résumé : BACKGROUND: The key pathological mechanisms underlying autism spectrum disorder (ASD) remain relatively undetermined, potentially due to the heterogenous nature of the condition. Targeted studies of a series of monogenic ASDs have revealed postsynaptic dysfunction as a central conserved mechanism. Presynaptic dysfunction is emerging as an additional disease locus in neurodevelopmental disorders; however, it is unclear whether this dysfunction drives ASD or is an adaptation to the altered brain microenvironment. METHODS: To differentiate between these two competing scenarios, we performed a high content analysis of key stages of the synaptic vesicle lifecycle in primary neuronal cultures derived from a series of preclinical rat models of monogenic ASD. These five independent models (Nrxn1(+/-), Nlgn3(-/y), Syngap(+/-), Syngap(+/?-GAP), Pten(+/-)) were specifically selected to have perturbations in a diverse palette of genes that were expressed either at the pre- or post-synapse. Synaptic vesicle exocytosis and cargo trafficking were triggered via two discrete trains of activity and monitored using the genetically-encoded reporter synaptophysin-pHluorin. Activity-dependent bulk endocytosis was assessed during intense neuronal activity using the fluid phase marker tetramethylrhodamine-dextran. RESULTS: Both synaptic vesicle fusion events and cargo trafficking were unaffected in all models investigated under all stimulation protocols. However, a key convergent phenotype across neurons derived from all five models was revealed, a depression in activity-dependent bulk endocytosis. LIMITATIONS: The study is exclusively conducted in primary cultures of hippocampal neurons; therefore, the impact on neurons from other brain regions or altered brain microcircuitry was not assessed. No molecular mechanism has been identified for this depression. CONCLUSION: This suggests that depression of activity-dependent bulk endocytosis is a presynaptic homeostatic mechanism to correct for intrinsic dysfunction in ASD neurons. En ligne : https://dx.doi.org/10.1186/s13229-025-00660-6 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=555 [article] Convergent depression of activity-dependent bulk endocytosis in rodent models of autism spectrum disorder [texte imprimé] / Mohammed Sarfaraz NAWAZ, Auteur ; Peter C. KIND, Auteur ; Michael A. COUSIN, Auteur . - 26. Langues : Anglais (eng) in Molecular Autism > 16 (2025) . - 26 Mots-clés : Animals  Endocytosis  Disease Models, Animal  Rats  Synaptic Vesicles/metabolism  Autism Spectrum Disorder/metabolism/physiopathology/genetics/pathology  Neurons/metabolism  Cells, Cultured  Exocytosis  Activity  Autism  Hippocampus  Presynapse  Rat  Vesicle  performed in accordance with the UK Animal (Scientific Procedures) Act 1986,  under Project and Personal Licence authority and were approved by the Animal  Welfare and Ethical Review Body at the University of Edinburgh (Home Office  project licence - 7008878). Similarly, procedures were conducted in accordance  with protocols approved by the Institutional Animal Ethics Committee of Institute  for Stem Cell Science and Regenerative Medicine, Bangalore. Consent for  publication: Not applicable. Competing interests: Peter Kind is an Associate  Editor for Molecular Autism. Index. décimale : PER Périodiques Résumé : BACKGROUND: The key pathological mechanisms underlying autism spectrum disorder (ASD) remain relatively undetermined, potentially due to the heterogenous nature of the condition. Targeted studies of a series of monogenic ASDs have revealed postsynaptic dysfunction as a central conserved mechanism. Presynaptic dysfunction is emerging as an additional disease locus in neurodevelopmental disorders; however, it is unclear whether this dysfunction drives ASD or is an adaptation to the altered brain microenvironment. METHODS: To differentiate between these two competing scenarios, we performed a high content analysis of key stages of the synaptic vesicle lifecycle in primary neuronal cultures derived from a series of preclinical rat models of monogenic ASD. These five independent models (Nrxn1(+/-), Nlgn3(-/y), Syngap(+/-), Syngap(+/?-GAP), Pten(+/-)) were specifically selected to have perturbations in a diverse palette of genes that were expressed either at the pre- or post-synapse. Synaptic vesicle exocytosis and cargo trafficking were triggered via two discrete trains of activity and monitored using the genetically-encoded reporter synaptophysin-pHluorin. Activity-dependent bulk endocytosis was assessed during intense neuronal activity using the fluid phase marker tetramethylrhodamine-dextran. RESULTS: Both synaptic vesicle fusion events and cargo trafficking were unaffected in all models investigated under all stimulation protocols. However, a key convergent phenotype across neurons derived from all five models was revealed, a depression in activity-dependent bulk endocytosis. LIMITATIONS: The study is exclusively conducted in primary cultures of hippocampal neurons; therefore, the impact on neurons from other brain regions or altered brain microcircuitry was not assessed. No molecular mechanism has been identified for this depression. CONCLUSION: This suggests that depression of activity-dependent bulk endocytosis is a presynaptic homeostatic mechanism to correct for intrinsic dysfunction in ASD neurons. En ligne : https://dx.doi.org/10.1186/s13229-025-00660-6 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=555

Imbalance of flight-freeze responses and their cellular correlates in the Nlgn3(-/y) rat model of autism / Natasha J. ANSTEY in Molecular Autism, 13 (2022)  

Public ISBD [article]  inMolecular Autism > 13 (2022) . - 34 p. Titre : Imbalance of flight-freeze responses and their cellular correlates in the Nlgn3(-/y) rat model of autism Type de document : texte imprimé Auteurs : Natasha J. ANSTEY, Auteur ; Vijayakumar KAPGAL, Auteur ; Shashank TIWARI, Auteur ; Thomas C. WATSON, Auteur ; Anna K.H. TOFT, Auteur ; Owen R. DANDO, Auteur ; Felicity H. INKPEN, Auteur ; Paul S. BAXTER, Auteur ; Zrinko KOZIĆ, Auteur ; Adam D. JACKSON, Auteur ; Xin HE, Auteur ; Mohammed Sarfaraz NAWAZ, Auteur ; Aiman KAYENAAT, Auteur ; Aditi BHATTACHARYA, Auteur ; David J.A. WYLLIE, Auteur ; Sumantra CHATTARJI, Auteur ; Emma R. WOOD, Auteur ; Oliver HARDT, Auteur ; Peter C. KIND, Auteur Article en page(s) : 34 p. Langues : Anglais (eng) Mots-clés : Animals  Autistic Disorder/metabolism  Fear/physiology  Freezing  Humans  Neurons/physiology  Periaqueductal Gray/metabolism  Rats  Autism  Fear  Flight  Intellectual disability  Neuroligin-3  Periaqueductal grey Index. décimale : PER Périodiques Résumé : BACKGROUND: Mutations in the postsynaptic transmembrane protein neuroligin-3 are highly correlative with autism spectrum disorders (ASDs) and intellectual disabilities (IDs). Fear learning is well studied in models of these disorders, however differences in fear response behaviours are often overlooked. We aim to examine fear behaviour and its cellular underpinnings in a rat model of ASD/ID lacking Nlgn3. METHODS: This study uses a range of behavioural tests to understand differences in fear response behaviour in Nlgn3(-/y) rats. Following this, we examined the physiological underpinnings of this in neurons of the periaqueductal grey (PAG), a midbrain area involved in flight-or-freeze responses. We used whole-cell patch-clamp recordings from ex vivo PAG slices, in addition to in vivo local-field potential recordings and electrical stimulation of the PAG in wildtype and Nlgn3(-/y) rats. We analysed behavioural data with two- and three-way ANOVAS and electrophysiological data with generalised linear mixed modelling (GLMM). RESULTS: We observed that, unlike the wildtype, Nlgn3(-/y) rats are more likely to response with flight rather than freezing in threatening situations. Electrophysiological findings were in agreement with these behavioural outcomes. We found in ex vivo slices from Nlgn3(-/y) rats that neurons in dorsal PAG (dPAG) showed intrinsic hyperexcitability compared to wildtype. Similarly, stimulating dPAG in vivo revealed that lower magnitudes sufficed to evoke flight behaviour in Nlgn3(-/y) than wildtype rats, indicating the functional impact of the increased cellular excitability. LIMITATIONS: Our findings do not examine what specific cell type in the PAG is likely responsible for these phenotypes. Furthermore, we have focussed on phenotypes in young adult animals, whilst the human condition associated with NLGN3 mutations appears during the first few years of life. CONCLUSIONS: We describe altered fear responses in Nlgn3(-/y) rats and provide evidence that this is the result of a circuit bias that predisposes flight over freeze responses. Additionally, we demonstrate the first link between PAG dysfunction and ASD/ID. This study provides new insight into potential pathophysiologies leading to anxiety disorders and changes to fear responses in individuals with ASD. En ligne : http://dx.doi.org/10.1186/s13229-022-00511-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=491 [article] Imbalance of flight-freeze responses and their cellular correlates in the Nlgn3(-/y) rat model of autism [texte imprimé] / Natasha J. ANSTEY, Auteur ; Vijayakumar KAPGAL, Auteur ; Shashank TIWARI, Auteur ; Thomas C. WATSON, Auteur ; Anna K.H. TOFT, Auteur ; Owen R. DANDO, Auteur ; Felicity H. INKPEN, Auteur ; Paul S. BAXTER, Auteur ; Zrinko KOZIĆ, Auteur ; Adam D. JACKSON, Auteur ; Xin HE, Auteur ; Mohammed Sarfaraz NAWAZ, Auteur ; Aiman KAYENAAT, Auteur ; Aditi BHATTACHARYA, Auteur ; David J.A. WYLLIE, Auteur ; Sumantra CHATTARJI, Auteur ; Emma R. WOOD, Auteur ; Oliver HARDT, Auteur ; Peter C. KIND, Auteur . - 34 p. Langues : Anglais (eng) in Molecular Autism > 13 (2022) . - 34 p. Mots-clés : Animals  Autistic Disorder/metabolism  Fear/physiology  Freezing  Humans  Neurons/physiology  Periaqueductal Gray/metabolism  Rats  Autism  Fear  Flight  Intellectual disability  Neuroligin-3  Periaqueductal grey Index. décimale : PER Périodiques Résumé : BACKGROUND: Mutations in the postsynaptic transmembrane protein neuroligin-3 are highly correlative with autism spectrum disorders (ASDs) and intellectual disabilities (IDs). Fear learning is well studied in models of these disorders, however differences in fear response behaviours are often overlooked. We aim to examine fear behaviour and its cellular underpinnings in a rat model of ASD/ID lacking Nlgn3. METHODS: This study uses a range of behavioural tests to understand differences in fear response behaviour in Nlgn3(-/y) rats. Following this, we examined the physiological underpinnings of this in neurons of the periaqueductal grey (PAG), a midbrain area involved in flight-or-freeze responses. We used whole-cell patch-clamp recordings from ex vivo PAG slices, in addition to in vivo local-field potential recordings and electrical stimulation of the PAG in wildtype and Nlgn3(-/y) rats. We analysed behavioural data with two- and three-way ANOVAS and electrophysiological data with generalised linear mixed modelling (GLMM). RESULTS: We observed that, unlike the wildtype, Nlgn3(-/y) rats are more likely to response with flight rather than freezing in threatening situations. Electrophysiological findings were in agreement with these behavioural outcomes. We found in ex vivo slices from Nlgn3(-/y) rats that neurons in dorsal PAG (dPAG) showed intrinsic hyperexcitability compared to wildtype. Similarly, stimulating dPAG in vivo revealed that lower magnitudes sufficed to evoke flight behaviour in Nlgn3(-/y) than wildtype rats, indicating the functional impact of the increased cellular excitability. LIMITATIONS: Our findings do not examine what specific cell type in the PAG is likely responsible for these phenotypes. Furthermore, we have focussed on phenotypes in young adult animals, whilst the human condition associated with NLGN3 mutations appears during the first few years of life. CONCLUSIONS: We describe altered fear responses in Nlgn3(-/y) rats and provide evidence that this is the result of a circuit bias that predisposes flight over freeze responses. Additionally, we demonstrate the first link between PAG dysfunction and ASD/ID. This study provides new insight into potential pathophysiologies leading to anxiety disorders and changes to fear responses in individuals with ASD. En ligne : http://dx.doi.org/10.1186/s13229-022-00511-8 Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=491

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