10 results on '"Jackson, Adam D."'
Search Results
2. Imbalance of flight–freeze responses and their cellular correlates in the Nlgn3−/y rat model of autism
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Anstey, Natasha J., Kapgal, Vijayakumar, Tiwari, Shashank, Watson, Thomas C., Toft, Anna K. H., Dando, Owen R., Inkpen, Felicity H., Baxter, Paul S., Kozić, Zrinko, Jackson, Adam D., He, Xin, Nawaz, Mohammad Sarfaraz, Kayenaat, Aiman, Bhattacharya, Aditi, Wyllie, David J. A., Chattarji, Sumantra, Wood, Emma R., Hardt, Oliver, and Kind, Peter C.
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- 2022
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3. Altered dendritic spine function and integration in a mouse model of fragile X syndrome
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Booker, Sam A., Domanski, Aleksander P. F., Dando, Owen R., Jackson, Adam D., Isaac, John T. R., Hardingham, Giles E., Wyllie, David J. A., and Kind, Peter C.
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- 2019
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4. Conserved hippocampal cellular pathophysiology but distinct behavioural deficits in a new rat model of FXS
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Till, Sally M., Asiminas, Antonis, Jackson, Adam D., Katsanevaki, Danai, Barnes, Stephanie A., Osterweil, Emily K., Bear, Mark F., Chattarji, Sumantra, Wood, Emma R., Wyllie, David J.A., and Kind, Peter C.
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- 2015
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5. Imbalance of flight–freeze responses and their cellular correlates in the Nlgn3−/y rat model of autism.
- Author
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Anstey, Natasha J., Kapgal, Vijayakumar, Tiwari, Shashank, Watson, Thomas C., Toft, Anna K. H., Dando, Owen R., Inkpen, Felicity H., Baxter, Paul S., Kozić, Zrinko, Jackson, Adam D., He, Xin, Nawaz, Mohammad Sarfaraz, Kayenaat, Aiman, Bhattacharya, Aditi, Wyllie, David J. A., Chattarji, Sumantra, Wood, Emma R., Hardt, Oliver, and Kind, Peter C.
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ANIMAL disease models ,AUTISM spectrum disorders ,NEURAL transmission ,AUTISM ,ELECTRIC stimulation ,INTELLECTUAL disabilities - Abstract
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. [ABSTRACT FROM AUTHOR]- Published
- 2022
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6. Conserved hippocampal cellular pathophysiology but distinct behavioural deficits in a rat model of Fragile X Syndrome
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Till, Sally M, Asiminas, Antonis, Jackson, Adam D, Katsanevaki, Danai, Barnes, Stephanie A, Osterweil, Emily K, Bear, Mark F, Chattarji, Sumantra, Wood, Emma R, Wyllie, David J A, and Kind, Peter C
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congenital, hereditary, and neonatal diseases and abnormalities - Abstract
Recent advances in techniques for manipulating genomes have allowed thegeneration of transgenic animals other than mice. These new models enable crossmammalian comparison of neurological disease from core cellular pathophysiology to circuit and behavioural endophenotypes. Moreover they will enable us to directly test whether common cellular dysfunction or behavioural outcomes of a genetic mutation are more conserved across species. Using a new rat model of Fragile X Syndrome (FXS), we report that Fmr1 knockout (KO) rats exhibit elevated basal protein synthesis and an increase in mGluR-dependent long-term depression (LTD) in CA1 of the hippocampus that is independent of new protein synthesis. These defects in plasticity are accompanied by an increase in dendritic spine density selectively in apical dendrites and subtle changes in dendritic spine morphology of CA1 pyramidal neurons. Behaviourally, Fmr1 KO rats show deficits in hippocampal-dependent, but not hippocampal-independent, forms of associative recognition memory indicating that the loss of FMRP causes defects in episodic-like memory. In contrast to previous reports from mice, Fmr1 KO rats show no deficits in spatial reference memory reversal learning. One-trial spatial learning in a delayed matching to place water maze task was also not affected by the loss of FMRP in rats. This is the first evidence for conservation across mammalian species of cellular and physiological hippocampal phenotypes associated with the loss of FMRP. Furthermore, while key cellular phenotypes are conserved they manifest in distinct behavioural dysfunction. Finally, our data reveal novel information about the selective role of FMRP in hippocampus-dependent associative memory.
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- 2015
7. Sustained correction of associative learning deficits after brief, early treatment in a rat model of Fragile X Syndrome.
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Asiminas, Antonis, Jackson, Adam D., Louros, Susana R., Till, Sally M., Spano, Teresa, Dando, Owen, Bear, Mark F., Chattarji, Sumantra, Hardingham, Giles E., Osterweil, Emily K., Wyllie, David J. A., Wood, Emma R., and Kind, Peter C.
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FRAGILE X syndrome ,ASSOCIATIVE learning ,TERMINATION of treatment ,COGNITIVE development ,ANTICHOLESTEREMIC agents ,COGNITION in children ,LEARNING strategies - Abstract
Optimizing therapeutic intervention for Fragile X Syndrome: Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by mutations in the FMR1 gene. Pharmacological intervention using the cholesterol-lowering drug lovastatin had therapeutic effect on behavior in patients. Selecting the time of intervention and the therapeutic protocol is critical for maximizing the therapeutic effects. Now, Asiminas et al. tested the effect of temporary early treatment with lovastatin in a rat model of FXS. The authors showed that 5-week treatment initiated before complete development of cognitive abilities rescued cognitive development. The therapeutic effect persisted for more than 3 months after treatment termination. The results suggest that lovastatin treatment initiated early during development might have disease-modifying effect in FXS. Fragile X Syndrome (FXS) is one of the most common monogenic forms of autism and intellectual disability. Preclinical studies in animal models have highlighted the potential of pharmaceutical intervention strategies for alleviating the symptoms of FXS. However, whether treatment strategies can be tailored to developmental time windows that define the emergence of particular phenotypes is unknown. Similarly, whether a brief, early intervention can have long-lasting beneficial effects, even after treatment cessation, is also unknown. To address these questions, we first examined the developmental profile for the acquisition of associative learning in a rat model of FXS. Associative memory was tested using a range of behavioral paradigms that rely on an animal's innate tendency to explore novelty. Fmr1 knockout (KO) rats showed a developmental delay in their acquisition of object-place recognition and did not demonstrate object-place-context recognition paradigm at any age tested (up to 23 weeks of age). Treatment of Fmr1 KO rats with lovastatin between 5 and 9 weeks of age, during the normal developmental period that this associative memory capability is established, prevents the emergence of deficits but has no effect in wild-type animals. Moreover, we observe no regression of cognitive performance in the FXS rats over several months after treatment. This restoration of the normal developmental trajectory of cognitive function is associated with the sustained rescue of both synaptic plasticity and altered protein synthesis. The findings provide proof of concept that the impaired emergence of the cognitive repertoire in neurodevelopmental disorders may be prevented by brief, early pharmacological intervention. [ABSTRACT FROM AUTHOR]
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- 2019
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8. Convergence of Hippocampal Pathophysiology in Syngap+/- and Fmr1-/y Mice.
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Barnes, Stephanie A., Wijetunge, Lasani S., Jackson, Adam D., Katsanevaki, Danai, Osterweil, Emily K., Komiyama, Noboru H., Grant, Seth G. N., Bear, Mark F., Nägerl, U. Valentin, Kind, Peter C., and Wyllie, David J. A.
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HIPPOCAMPUS diseases ,INTELLECTUAL disabilities ,AUTISM spectrum disorders ,PHENOTYPES ,DELETION mutation ,GLUTAMATE receptors ,DENDRITIC spines - Abstract
Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap
+/- and Fmr1-/y mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap+/- hippocampal slices. Super-resolution microscopy reveals that Syngap+/- and Fmr1-/y mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras-ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency. [ABSTRACT FROM AUTHOR]- Published
- 2015
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9. Input-Output Relationship of CA1 Pyramidal Neurons Reveals Intact Homeostatic Mechanisms in a Mouse Model of Fragile X Syndrome.
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Booker SA, Simões de Oliveira L, Anstey NJ, Kozic Z, Dando OR, Jackson AD, Baxter PS, Isom LL, Sherman DL, Hardingham GE, Brophy PJ, Wyllie DJA, and Kind PC
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- Animals, Disease Models, Animal, Homeostasis, Mice, Fragile X Syndrome genetics, Pyramidal Cells metabolism
- Abstract
Cellular hyperexcitability is a salient feature of fragile X syndrome animal models. The cellular basis of hyperexcitability and how it responds to changing activity states is not fully understood. Here, we show increased axon initial segment length in CA1 of the Fmr1
-/y mouse hippocampus, with increased cellular excitability. This change in length does not result from reduced AIS plasticity, as prolonged depolarization induces changes in AIS length independent of genotype. However, depolarization does reduce cellular excitability, the magnitude of which is greater in Fmr1-/y neurons. Finally, we observe reduced functional inputs from the entorhinal cortex, with no genotypic difference in the firing rates of CA1 pyramidal neurons. This suggests that AIS-dependent hyperexcitability in Fmr1-/y mice may result from adaptive or homeostatic regulation induced by reduced functional synaptic connectivity. Thus, while AIS length and intrinsic excitability contribute to cellular hyperexcitability, they may reflect a homeostatic mechanism for reduced synaptic input onto CA1 neurons., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2020
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10. Convergence of Hippocampal Pathophysiology in Syngap+/- and Fmr1-/y Mice.
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Barnes SA, Wijetunge LS, Jackson AD, Katsanevaki D, Osterweil EK, Komiyama NH, Grant SG, Bear MF, Nägerl UV, Kind PC, and Wyllie DJ
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- Animals, Dendritic Spines metabolism, Dendritic Spines pathology, Excitatory Postsynaptic Potentials physiology, Fragile X Mental Retardation Protein genetics, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, Organ Culture Techniques, ras GTPase-Activating Proteins genetics, Fragile X Mental Retardation Protein biosynthesis, Hippocampus metabolism, Hippocampus physiopathology, ras GTPase-Activating Proteins biosynthesis
- Abstract
Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap(+/-) and Fmr1(-/y) mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap(+/-) hippocampal slices. Super-resolution microscopy reveals that Syngap(+/-) and Fmr1(-/y) mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras-ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency., Significance Statement: As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically divergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap(+/-) mice phenocopy Fmr1(-/y) mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu5 receptor-ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1(-/y) mice. Our findings support the hypothesis that phenotypes associated with genetically diverse forms of ID/ASDs result from alterations in common cellular/biochemical pathways., (Copyright © 2015 Barnes et al.)
- Published
- 2015
- Full Text
- View/download PDF
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