scholarly journals Neuroanatomy and Behaviour in Mice with a Haploinsufficiency of AT-Rich Interactive Domain 1B (ARID1B) Throughout Development

2020 ◽  
Author(s):  
Jacob Ellegood ◽  
Stela P Petkova ◽  
Adrienne Kinman ◽  
Lily R Qiu ◽  
Ayanna Wade ◽  
...  

Abstract Background - One of the causal mechanisms underlying neurodevelopmental disorders (NDDs) is chromatin modification, and the genes that regulate chromatin. AT-Rich Interactive Domain 1B (ARID1B) , a chromatin modifier, has been shown to be reduced in autism spectrum disorder (ASD) and to affect rare and inherited genetic variation in a broad set of NDDs. Methods - A novel preclinical mouse model of Arid1b deficiency was created validated to characterize and define neuroanatomical, behavioural and tran­scriptional phenotypes. Neuroanatomy was assess ex vivo in adult animals and in vivo longitudinally from birth to adulthood. Behavioural testing was also performed throughout development and tested all aspects of motor, learning, sociability, repetitive behaviours, seizure susceptibility and general milestones.Results - Brains of adult Arid1b+/- mice had a smaller cerebellum and a larger hippocampus and corpus callosum. These results stand in contrast to previously reported data highlighting losses in corpus callosum volume. In addition, a striking sex dependence was observed throughout development; males had an early emergence of this neuroanatomical phenotype at postnatal day 7, whereas females had a delayed emergence around postnatal day 40. Behaviourally, during neonatal development, Arid1b+/- mice exhibited robust impairments in ultrasonic vocalizations (USVs) and metrics of developmental growth. As adults, Arid1b+/- mice showed low motor skills in open field exploration and normal three chambered approach. Arid1b+/- mice had learning and memory deficits in novel object recognition but not in visual discrimination and reversal touchscreen tasks. Social interactions in the male-female social dyad with USVs revealed social deficits on some but not all parameters. No repetitive behaviours were observed. Limitations – The behaviour and the neuroimaging analysis were done on separate cohorts of mice, which does not allow a direct correlation between the imaging and behavioural findings. Conclusions – This study represents a full investigation of Arid1b+/- haploinsufficiency throughout development and highlights the importance of examining both sexes throughout development in NDDs.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. Ellegood ◽  
S. P. Petkova ◽  
A. Kinman ◽  
L. R. Qiu ◽  
A. Adhikari ◽  
...  

Abstract Background One of the causal mechanisms underlying neurodevelopmental disorders (NDDs) is chromatin modification and the genes that regulate chromatin. AT-rich interactive domain 1B (ARID1B), a chromatin modifier, has been linked to autism spectrum disorder and to affect rare and inherited genetic variation in a broad set of NDDs. Methods A novel preclinical mouse model of Arid1b deficiency was created and validated to characterize and define neuroanatomical, behavioral and transcriptional phenotypes. Neuroanatomy was assessed ex vivo in adult animals and in vivo longitudinally from birth to adulthood. Behavioral testing was also performed throughout development and tested all aspects of motor, learning, sociability, repetitive behaviors, seizure susceptibility, and general milestones delays. Results We validated decreased Arid1b mRNA and protein in Arid1b+/− mice, with signatures of increased axonal and synaptic gene expression, decreased transcriptional regulator and RNA processing expression in adult Arid1b+/− cerebellum. During neonatal development, Arid1b+/− mice exhibited robust impairments in ultrasonic vocalizations (USVs) and metrics of developmental growth. In addition, a striking sex effect was observed neuroanatomically throughout development. Behaviorally, as adults, Arid1b+/− mice showed low motor skills in open field exploration and normal three-chambered approach. Arid1b+/− mice had learning and memory deficits in novel object recognition but not in visual discrimination and reversal touchscreen tasks. Social interactions in the male–female social dyad with USVs revealed social deficits on some but not all parameters. No repetitive behaviors were observed. Brains of adult Arid1b+/− mice had a smaller cerebellum and a larger hippocampus and corpus callosum. The corpus callosum increase seen here contrasts previous reports which highlight losses in corpus callosum volume in mice and humans. Limitations The behavior and neuroimaging analyses were done on separate cohorts of mice, which did not allow a direct correlation between the imaging and behavioral findings, and the transcriptomic analysis was exploratory, with no validation of altered expression beyond Arid1b. Conclusions This study represents a full validation and investigation of a novel model of Arid1b+/− haploinsufficiency throughout development and highlights the importance of examining both sexes throughout development in NDDs.


2020 ◽  
Author(s):  
J. Ellegood ◽  
S.P. Petkova ◽  
A. Kinman ◽  
L.R. Qiu ◽  
A. Wade ◽  
...  

AbstractOne of the causal mechanisms underlying neurodevelopmental disorders (NDDs) is chromatin modification, and genes that regulate chromatin modify and control events regulating the formation of neural connections. AT-Rich Interactive Domain 1B (ARID1B), a chromatin modifier, has been shown to be reduced in autism spectrum disorder (ASD) and to affect rare and inherited genetic variation in a broad set of NDDs. For this work, a novel preclinical mouse model of Arid1b deficiency was created and molecularly validated to characterize and define neuroanatomical, behavioural and transcriptional phenotypes. Brains of adult Arid1b+/- mice had a smaller cerebellum along with a larger hippocampus and corpus callosum. In addition, a notable sex dependence was observed throughout development; males had an early emergence of the neuroanatomical phenotype around postnatal day 7, whereas females had a delayed emergence of the phenotype around postnatal day 40. Behavioural assays relevant to NDD were conducted during neonatal development and adulthood to evaluate general health, anxiety-like, motor, cognitive, and social behaviours in Arid1b+/- mice. During neonatal development, Arid1b+/- mice exhibited robust impairments in ultrasonic vocalizations (USVs) and metrics of developmental growth. As adults, Arid1b+/- mice showed low motor skills in open field exploration and normal three chambered approach. Arid1b+/- mice had learning and memory deficits in novel object recognition but surprisingly not in visual discrimination and reversal touchscreen tasks. Social interactions in the male-female social dyad with USVs revealed social deficits on some but not all parameters. No repetitive behaviours were observed. This study represents a full investigation of Arid1b+/- haploinsufficiency throughout development and highlights the importance of examining both sexes throughout development in NDDs.


2021 ◽  
Author(s):  
Stamatina Tzanoulinou ◽  
Stefano Musardo ◽  
Alessandro Contestabile ◽  
Sebastiano Bariselli ◽  
Giulia Casarotto ◽  
...  

Autism spectrum disorder is a neurodevelopmental disease characterized by social deficits and repetitive behaviors. The high heterogeneity of the disease may be explained by gene and environmental interactions and potential risk factors include immune dysfunctions and immune-mediated co-morbidities. Mutations in the SHANK3 gene have been recognized as a genetic risk factor for ASD. While heterozygous SHANK3 mutations are usually the types of mutations associated with idiopathic autism in patients, heterozygous deletion of Shank3 gene in mice does not commonly induce ASD-related behavioural deficit. Here, we used in-vivo and ex-vivo approaches to demonstrate that region-specific neonatal downregulation of Shank3 in the NAc promotes D1R-MSN hyperexcitability and upregulates Trpv4 to impair social behaviour. Interestingly, genetically vulnerable Shank3+/- mice, when challenged with Lipopolysaccharide to induce inflammatory response, showed similar circuit and behavioural alterations that were rescued by acute Trpv4 inhibition. Altogether our data demonstrate shared molecular and circuit mechanisms between ASD-relevant genetic alterations and environmental insults, which ultimately lead to sociability dysfunctions.


2020 ◽  
Author(s):  
Natasha J Anstey ◽  
Vijayakumar Kapgal ◽  
Shashank Tiwari ◽  
Thomas C Watson ◽  
Anna KH Toft ◽  
...  

SummaryMutations 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. Whilst examining fear in a rat model of ASD/ID lacking Nlgn3, we observed that they display a greater propensity to exhibit flight responses in contrast to classic freezing seen in wildtypes during fearful situations. Consequently, we examined the physiological underpinnings of this in neurons of the periaqueductal grey (PAG), a midbrain area involved in flight-or-freeze responses. In ex vivo slices from Nlgn3-/y, rats, dorsal PAG (dPAG) neurons showed intrinsic hyperexcitability. Further analysis of this revealed lower magnitude in vivo dPAG stimulation evoked flight behaviour in Nlgn3-/y, rats, indicating the functional impact of the increased cellular excitability. This study provides new insight into potential pathophysiologies leading to emotional disorders in individuals with ASD.


2020 ◽  
Author(s):  
Mo Xian Chen ◽  
Shu Cheng ◽  
Lei Lei ◽  
Chloe U Wallis ◽  
Qiang Liu ◽  
...  

Abstract Background Prenatal exposure to selective serotonin reuptake inhibitor (SSRI), such as fluoxetine (FLX) may increase susceptibility to autism spectrum disorder (ASD). However, findings from published studies on SSRI and ASD are inconsistent. The use of a rodent model can provide a clear indication as to whether prenatal exposure to SSRIs, independent of maternal psychiatric disorders or genetic syndromes, can cause long-term behavioral and ASD-related neurobiological abnormalities in offspring. Methods FLX or normal saline (NS) was administered to pregnant Sprague-Dawley (SD) rats (FLX=30, NS=27) on gestation day 11 till birth. The resulting offspring were assessed in terms of their physical development and behavior, and underwent in vivo magnetic resonance spectroscopy ( MRS) to quantify biochemical alterations in the prefrontal cortex (PFC). Ex vivo measurements of brain serotonin level and a proteomic analysis were also undertaken. Results The offspring (male offspring in particular) of fluoxetine exposed mothers showed delayed physical development, increased anxiety and impaired social interaction. Moreover, down-regulation of 5-HT or SERT expression and up-regulation of TPH levels was observed in the PFC. We also found that prenatal FLX exposure significantly decreased NAA/tCr with 1 H-MRS in the PFC. Finally, a proteomic study revealed sex-dependent differential protein expression. ConclusionsThese findings may have translational importance suggesting that the use of SSRI medication alone in pregnant mothers may result in developmental delay and autistic-like behavior in their offspring. Our results also help to guide the choice of outcome measures in the identification of molecular and developmental mechanisms that may confer vulnerability in ASD.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Faye McKenna ◽  
Laura Miles ◽  
Jeffrey Donaldson ◽  
F. Xavier Castellanos ◽  
Mariana Lazar

AbstractPrior ex vivo histological postmortem studies of autism spectrum disorder (ASD) have shown gray matter microstructural abnormalities, however, in vivo examination of gray matter microstructure in ASD has remained scarce due to the relative lack of non-invasive methods to assess it. The aim of this work was to evaluate the feasibility of employing diffusional kurtosis imaging (DKI) to describe gray matter abnormalities in ASD in vivo. DKI data were examined for 16 male participants with a diagnosis of ASD and IQ>80 and 17 age- and IQ-matched male typically developing (TD) young adults 18–25 years old. Mean (MK), axial (AK), radial (RK) kurtosis and mean diffusivity (MD) metrics were calculated for lobar and sub-lobar regions of interest. Significantly decreased MK, RK, and MD were found in ASD compared to TD participants in the frontal and temporal lobes and several sub-lobar regions previously associated with ASD pathology. In ASD participants, decreased kurtosis in gray matter ROIs correlated with increased repetitive and restricted behaviors and poor social interaction symptoms. Decreased kurtosis in ASD may reflect a pathology associated with a less restrictive microstructural environment such as decreased neuronal density and size, atypically sized cortical columns, or limited dendritic arborizations.


2011 ◽  
Vol 67 (3) ◽  
pp. 750-759 ◽  
Author(s):  
Jiangyang Zhang ◽  
Melina V. Jones ◽  
Michael T. McMahon ◽  
Susumu Mori ◽  
Peter A. Calabresi

2020 ◽  
Author(s):  
Benjamin m Aertker ◽  
Akshita Kumar ◽  
Henry W Caplan ◽  
Fanni B Cardenas ◽  
Charles S Cox ◽  
...  

Abstract Background: Traumatic brain injury (TBI) disrupts the complex arrangement of neuronal and glial cells. As a result of TBI there is activation of microglia. Activated microglia after injury can be measured in vivo by using positron emission topography (PET) ligand peripheral benzodiazepine receptor (PBR28) and their phenotypes (activated vs resting) can be assessed (ex vivo) using morphology. This study aims to utilize in vivo (PET) and ex vivo (morphology) to assess the changes in microglia after a controlled cortical impact (CCI), a rodent model for TBI.Methods: Male Sprague Dawley rats underwent a sham injury or severe CCI. Microglia activation was assessed 120 hours after the injury by PET/CT imaging using the radioligand [11C] PBR-28. Standardized uptake values (PBR28suv) were calculated over the duration of the scan and mean values were compared. In order to verify in vivo results, ex vivo morphological analysis [ramified (resting) or amoeboid-shaped (activated)] was performed (dentate gyrus, corpus callosum and thalamus) with the antibody IBA-1. To further conclude that PBR is a marker for activated microglia after CCI, we examined co-staining of PBR with microglia and astrocytes.Results: In vivo and ex vivo results were complementary. Injured animals displayed greater PBR28suv when compared to sham animals. Immunohistochemistry demonstrated elevated numbers of activated microglia in the ipsilateral dentate gyrus, corpus callosum and thalami of injured animals compared to sham animals. Additionally, PBR co-stained with microglia and not astrocytes.Conclusion: CCI, a rodent model of TBI resulted in a significant increase in PBR28suv due to injury. Similarly, morphological analysis demonstrated a significant increase in amoeboid-shaped (activated) microglia. These results serve as a surrogate marker for increased neuroinflammation in the brains of severely injured animals. PBR28suv can serve as an in vivo tracking system for monitoring neuroinflammation following TBI and cellular therapies.


Author(s):  
Stamatina Tzanoulinou ◽  
Stefano Musardo ◽  
Alessandro Contestabile ◽  
Sebastiano Bariselli ◽  
Giulia Casarotto ◽  
...  

AbstractMutations in the SHANK3 gene have been recognized as a genetic risk factor for Autism Spectrum Disorder (ASD), a neurodevelopmental disease characterized by social deficits and repetitive behaviors. While heterozygous SHANK3 mutations are usually the types of mutations associated with idiopathic autism in patients, heterozygous deletion of Shank3 gene in mice does not commonly induce ASD-related behavioral deficit. Here, we used in-vivo and ex-vivo approaches to demonstrate that region-specific neonatal downregulation of Shank3 in the Nucleus Accumbens promotes D1R-medium spiny neurons (D1R-MSNs) hyperexcitability and upregulates Transient Receptor Potential Vanilloid 4 (Trpv4) to impair social behavior. Interestingly, genetically vulnerable Shank3+/− mice, when challenged with Lipopolysaccharide to induce an acute inflammatory response, showed similar circuit and behavioral alterations that were rescued by acute Trpv4 inhibition. Altogether our data demonstrate shared molecular and circuit mechanisms between ASD-relevant genetic alterations and environmental insults, which ultimately lead to sociability dysfunctions.


2021 ◽  
Vol 15 ◽  
Author(s):  
Jianbo Liu ◽  
Yujie Liang ◽  
Xing Jiang ◽  
Jianchang Xu ◽  
Yumeng Sun ◽  
...  

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by impaired skills in social interaction and communication in addition to restricted and repetitive behaviors. Many different factors may contribute to ASD development; in particular, oxytocin receptor (OXTR) deficiency has been reported to be associated with ASD, although the detailed mechanism has remained largely unknown. Epidemiological study has shown that maternal diabetes is associated with ASD development. In this study, we aim to investigate the potential role of OXTR on maternal diabetes-mediated social deficits in offspring. Our in vitro study of human neuron progenitor cells showed that hyperglycemia induces OXTR suppression and that this suppression remains during subsequent normoglycemia. Further investigation showed that OXTR suppression is due to hyperglycemia-induced persistent oxidative stress and epigenetic methylation in addition to the subsequent dissociation of estrogen receptor β (ERβ) from the OXTR promoter. Furthermore, our in vivo mouse study showed that maternal diabetes induces OXTR suppression; prenatal OXTR deficiency mimics and potentiates maternal diabetes-mediated anxiety-like behaviors, while there is less of an effect on autism-like behaviors. Additionally, postnatal infusion of OXTR partly, while infusion of ERβ completely, reverses maternal diabetes-induced social deficits. We conclude that OXTR may be an important factor for ASD development and that maternal diabetes-induced suppression of oxytocin receptor contributes to social deficits in offspring.


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