scholarly journals Selective impact of MeCP2 and associated histone deacetylases on the dynamics of evoked excitatory neurotransmission

2011 ◽  
Vol 106 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Erika D. Nelson ◽  
Manjot Bal ◽  
Ege T. Kavalali ◽  
Lisa M. Monteggia
Keyword(s):  
Histone Deacetylases ◽  
Hippocampal Neurons ◽  
Autism Spectrum ◽  
Synaptic Activity ◽  
Short Term ◽  
Histone Deacetylase 1 ◽  
Inhibitory Neurotransmission ◽  
Presynaptic Release ◽  
Excitatory Neurotransmission ◽  
Excitatory Drive

An imbalance between the strengths of excitatory and inhibitory synaptic inputs has been proposed as the cellular basis of autism and related neurodevelopmental disorders. Previous studies examining spontaneous levels of excitatory and inhibitory neurotransmission in the forebrain regions of methyl-CpG-binding protein 2 ( Mecp2) mutant mice, models of the autism spectrum disorder Rett syndrome, have identified a decrease in excitatory drive, in some cases coupled with an increase in inhibitory synaptic strength, as a major source of this imbalance. Here, we reevaluated this question by examining the short-term dynamics of evoked neurotransmission between hippocampal neurons cultured from MeCP2 knockout mice and found a marked increase in evoked excitatory neurotransmission that is consistent with an increase in presynaptic release probability. This increase in evoked excitatory drive was not matched with alterations in evoked inhibitory neurotransmission. Moreover, we observed similar excitatory drive specific changes after the loss of key histone deacetylases (histone deacetylase 1 and 2) that form a complex with MeCP2 and mediate transcriptional regulation. These findings suggest a distinct role for MeCP2 and its cofactors in the regulation of evoked excitatory neurotransmission compared with their essential role in basal synaptic activity.

A Simple Depletion Model of the Readily Releasable Pool of Synaptic Vesicles Cannot Account for Paired-Pulse Depression

2007 ◽  
Vol 97 (1) ◽  
pp. 948-950 ◽  
Author(s):  
Jane M. Sullivan
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Synaptic Activity ◽  
Excitatory Synapses ◽  
Short Term ◽  
Paired Pulse ◽  
Short Term Plasticity ◽  
Releasable Pool ◽  
Readily Releasable Pool ◽  
Paired Pulse Depression

Paired-pulse depression (PPD) is a form of short-term plasticity that plays a central role in processing of synaptic activity and is manifest as a decrease in the size of the response to the second of two closely timed stimuli. Despite mounting evidence to the contrary, PPD is still commonly thought to reflect depletion of the pool of synaptic vesicles available for release in response to the second stimulus. Here it is shown that PPD cannot be accounted for by depletion at excitatory synapses made by hippocampal neurons because PPD is unaffected by changes in the fraction of the readily releasable pool (RRP) released by the first of a pair of pulses.

scholarly journals RIM-binding protein 2 regulates release probability by fine-tuning calcium channel localization at murine hippocampal synapses

2016 ◽  
Vol 113 (41) ◽  
pp. 11615-11620 ◽  
Author(s):  
M. Katharina Grauel ◽  
Marta Maglione ◽  
Suneel Reddy-Alla ◽  
Claudia G. Willmes ◽  
Marisa M. Brockmann ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Autism Spectrum ◽  
Fine Tuning ◽  
Model Systems ◽  
Short Term ◽  
Superresolution Microscopy ◽  
Release Probability ◽  
Spatial Coupling ◽  
Hippocampal Synapses ◽  
Initial Release

The tight spatial coupling of synaptic vesicles and voltage-gated Ca2+ channels (CaVs) ensures efficient action potential-triggered neurotransmitter release from presynaptic active zones (AZs). Rab-interacting molecule-binding proteins (RIM-BPs) interact with Ca2+ channels and via RIM with other components of the release machinery. Although human RIM-BPs have been implicated in autism spectrum disorders, little is known about the role of mammalian RIM-BPs in synaptic transmission. We investigated RIM-BP2–deficient murine hippocampal neurons in cultures and slices. Short-term facilitation is significantly enhanced in both model systems. Detailed analysis in culture revealed a reduction in initial release probability, which presumably underlies the increased short-term facilitation. Superresolution microscopy revealed an impairment in CaV2.1 clustering at AZs, which likely alters Ca2+ nanodomains at release sites and thereby affects release probability. Additional deletion of RIM-BP1 does not exacerbate the phenotype, indicating that RIM-BP2 is the dominating RIM-BP isoform at these synapses.

scholarly journals Altered Expression of Cadherin-8 and Cadherin-11 in Neural Circuit Development: Implications for Autism

2020 ◽  
Author(s):  
Jeannine A. Frei ◽  
Robert F. Niescier ◽  
Morgan S. Bridi ◽  
Madel Durens ◽  
Jonathan E. Nestor ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Hippocampal Neurons ◽  
Neural Circuit ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Autism Spectrum ◽  
Synaptic Activity ◽  
Classical Type ◽  
Altered Expression ◽  
Expression Levels

AbstractAutism spectrum disorder (ASD) is a neurological condition characterized by difficulties in social interaction, communication, and behavior. The classical type II cadherins cadherin-8 (Cdh8, CDH8) and cadherin-11 (Cdh11, CDH11) have been implicated as autism risk gene candidates. To explore the role of cadherins in the etiology of autism, we investigated their expression patterns during mouse brain development and analyzed their functions using Cdh11 knockout mice. Expression of cadherin-8 and cadherin-11 was developmentally regulated and enriched in cortex, hippocampus, and thalamus/striatum during the peak of dendrite formation and synaptogenesis. Cadherin-8 preferentially localized to excitatory synapses where it interacted with neuroligin-1. Levels of cadherin-8, neuroligin-1, and PSD-95 were all significantly increased in Cdh11 knockout brains. Additionally, Cdh11-/- hippocampal neurons exhibited increased dendritic complexity along with altered neuronal and synaptic activity. Similar to the expression profiles in Cdh11 knockout mice, induced pluripotent stem cell (iPSC)-derived cortical neural precursor cells (NPCs) and cortical organoids generated from individuals with autism showed elevated CDH8 expression levels while CDH11 expression levels were decreased. Together, these results strongly suggest that cadherin-8 and cadherin-11 are involved in regulating the development of neuronal circuitry and that alterations in the expression levels of cadherin-8 and cadherin-11 may contribute to the etiology of autism.

scholarly journals EFFECTS OF ARTIFICIAL HYPOINSULINEMIA ON SYNAPTIC ACTIVITY AND PLASTICITY OF GLUTAMATERGIC NEUROTRANSMISSION IN CULTURE OF HIPPOCAMPAL NEURONS

2021 ◽  
Vol 67 (4) ◽  
pp. 3-11
Author(s):  
M.S. Shypshyna ◽  
◽  
K.I. Kuznetsov ◽  
S.A. Fedulova ◽  
M.S. Veselovsky ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Glutamate Release ◽  
Synaptic Activity ◽  
Short Term ◽  
Short Term Plasticity ◽  
Whole Cell Patch Clamp ◽  
Pulse Ratio ◽  
Coefficients Of Variation ◽  
Cultured Hippocampal Neurons

We investigated the effect of chronic hypoinsulinemia on the level of synaptic activity and short-term plasticity in cultured hippocampal neurons. Hypoinsulinemia was induced by culturing mature (16-20 days in vitro) rat’s hippocampal neurons without insulin for 1, 2, and 4 days. The control insulin concentration was 100 nM. Spontaneous and evoked glutamatergic excitatory postsynaptic currents (sEPSC and eEPSC, respectively) in these neurons were analyzed using the whole-cell patch-clamp method and the method of local electrical stimulation of individual axon. Hypoinsulinemia during the 1st, 2nd and 4th days led to significantly reduction of the mean sEPSC’s frequency to 49.9 ± 15.8% (n = 6), 8.5 ± 7.7% (n = 6) and 16.6 ± 5.2% (n = 8) respectively, relative to control. Also, there was a decrease of the average sEPSC’s amplitudes to 52.6 ± 5.5% (n = 6), 36.6 ± 5.8% (n = 6) and 43.9 ± 8.4% (n = 8), respectively, relative to control. Quantal analysis of the sEPSC’s amplitudes showed a decrease of multivesicular glutamate release at the synapses under such conditions. Hypoinsulinemia caused a shift in the direction of short-term plasticity in glutamatergic hippocampal synapses from potentiation to depression. The paired-pulse ratio decreased from 1.83 ± 0.25 in the control to 0.59 ± 0.07, 0.77 ± 0.07, and 0.80 ± 0.06 after the 1st, 2nd, and 4th days under cultivation without insulin. Accordingly, the ratio of the coefficients of variation of eEPSC’s amplitudes (CV2/ CV1) increased from 0.82 ± 0.07 to 1.30 ± 0.28, 1.52 ± 0.27, and 1.61 ± 0.24. The presented results indicate a significant reduction of synaptic activity and decrease in the probability of multivesicular release of glutamate at the synapses of cultured hippocampal neurons under hypoinsulinemia.

scholarly journals Application of Skeleton Data and Long Short-Term Memory in Action Recognition of Children with Autism Spectrum Disorder

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 411
Author(s):  
Yunkai Zhang ◽  
Yinghong Tian ◽  
Pingyi Wu ◽  
Dongfan Chen
Keyword(s):  
Autism Spectrum Disorder ◽  
Action Recognition ◽  
Short Term Memory ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Short Term ◽  
Term Memory ◽  
Clinical Observations ◽  
The Neural Network ◽  
Long Short Term Memory

The recognition of stereotyped action is one of the core diagnostic criteria of Autism Spectrum Disorder (ASD). However, it mainly relies on parent interviews and clinical observations, which lead to a long diagnosis cycle and prevents the ASD children from timely treatment. To speed up the recognition process of stereotyped actions, a method based on skeleton data and Long Short-Term Memory (LSTM) is proposed in this paper. In the first stage of our method, the OpenPose algorithm is used to obtain the initial skeleton data from the video of ASD children. Furthermore, four denoising methods are proposed to eliminate the noise of the initial skeleton data. In the second stage, we track multiple ASD children in the same scene by matching distance between current skeletons and previous skeletons. In the last stage, the neural network based on LSTM is proposed to classify the ASD children’s actions. The performed experiments show that our proposed method is effective for ASD children’s action recognition. Compared to the previous traditional schemes, our scheme has higher accuracy and is almost non-invasive for ASD children.

scholarly journals Neuroprotection by Histone Deacetylase-Related Protein

2006 ◽  
Vol 26 (9) ◽  
pp. 3550-3564 ◽  
Author(s):  
Brad E. Morrison ◽  
Nazanin Majdzadeh ◽  
Xiaoguang Zhang ◽  
Aaron Lyles ◽  
Rhonda Bassel-Duby ◽  
...  
Keyword(s):  
Cell Death ◽  
Histone Deacetylase ◽  
Neuronal Death ◽  
Histone Deacetylases ◽  
Essential Feature ◽  
Gene Promoter ◽  
Related Protein ◽  
Phosphatidylinositol 3 Kinase ◽  
Histone Deacetylase 1 ◽  
H3 Acetylation

ABSTRACT The expression of histone deacetylase-related protein (HDRP) is reduced in neurons undergoing apoptosis. Forced reduction of HDRP expression in healthy neurons by treatment with antisense oligonucleotides also induces cell death. Likewise, neurons cultured from mice lacking HDRP are more vulnerable to cell death. Adenovirally mediated expression of HDRP prevents neuronal death, showing that HDRP is a neuroprotective protein. Neuroprotection by forced expression of HDRP is not accompanied by activation of the phosphatidylinositol 3-kinase-Akt or Raf-MEK-ERK signaling pathway, and treatment with pharmacological inhibitors of these pathways fails to inhibit the neuroprotection by HDRP. Stimulation of c-Jun phosphorylation and expression, an essential feature of neuronal death, is prevented by HDRP. We found that HDRP associates with c-Jun N-terminal kinase (JNK) and inhibits its activity, thus explaining the inhibition of c-Jun phosphorylation by HDRP. HDRP also interacts with histone deacetylase 1 (HDAC1) and recruits it to the c-Jun gene promoter, resulting in an inhibition of histone H3 acetylation at the c-Jun promoter. Although HDRP lacks intrinsic deacetylase activity, treatment with pharmacological inhibitors of histone deacetylases induces apoptosis even in the presence of ectopically expressed HDRP, underscoring the importance of c-Jun promoter deacetylation by HDRP-HDAC1 in HDRP-mediated neuroprotection. Our results suggest that neuroprotection by HDRP is mediated by the inhibition of c-Jun through its interaction with JNK and HDAC1.

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