scholarly journals Emerging evidence implicating a role for neurexins in neurodegenerative and neuropsychiatric disorders

Open Biology ◽  
2021 ◽  
Vol 11 (10) ◽  
Author(s):  
Katelyn Cuttler ◽  
Maryam Hassan ◽  
Jonathan Carr ◽  
Ruben Cloete ◽  
Soraya Bardien
Keyword(s):  
Cell Adhesion ◽  
Neurodegenerative Disorders ◽  
Neuropsychiatric Disorders ◽  
Autism Spectrum ◽  
Synaptic Proteins ◽  
Brain Disorders ◽  
Binding Partners ◽  
Expression Studies ◽  
And Function ◽  
Cell Adhesion Proteins

Synaptopathies are brain disorders characterized by dysfunctional synapses, which are specialized junctions between neurons that are essential for the transmission of information. Synaptic dysfunction can occur due to mutations that alter the structure and function of synaptic components or abnormal expression levels of a synaptic protein. One class of synaptic proteins that are essential to their biology are cell adhesion proteins that connect the pre- and post-synaptic compartments. Neurexins are one type of synaptic cell adhesion molecule that have, recently, gained more pathological interest. Variants in both neurexins and their common binding partners, neuroligins, have been associated with several neuropsychiatric disorders. In this review, we summarize some of the key physiological functions of the neurexin protein family and the protein networks they are involved in. Furthermore, examination of published literature has implicated neurexins in both neuropsychiatric and neurodegenerative disorders. There is a clear link between neurexins and neuropsychiatric disorders, such as autism spectrum disorder and schizophrenia. However, multiple expression studies have also shown changes in neurexin expression in several neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. Therefore, this review highlights the potential importance of neurexins in brain disorders and the importance of doing more targeted studies on these genes and proteins.

scholarly journals ASTN2 modulates synaptic strength by trafficking and degradation of surface proteins

2018 ◽  
Author(s):  
Hourinaz Behesti ◽  
Taylor Fore ◽  
Peter Wu ◽  
Zachi Horn ◽  
Mary Leppert ◽  
...  
Keyword(s):  
Surface Protein ◽  
Surface Expression ◽  
Autism Spectrum ◽  
Copy Number Variations ◽  
Surface Proteins ◽  
Synaptic Activity ◽  
Synaptic Proteins ◽  
Dynamic Regulation ◽  
Cerebellar Purkinje Cells ◽  
And Function

AbstractSurface protein dynamics dictate synaptic connectivity and function in neuronal circuits. ASTN2, a gene disrupted by copy number variations (CNVs) in neurodevelopmental disorders, including autism spectrum, was previously shown to regulate the surface expression of ASTN1 in glial-guided neuronal migration. Here, we demonstrate that ASTN2 binds to and regulates the surface expression of multiple synaptic proteins in post-migratory neurons by endocytosis, resulting in modulation of synaptic activity. In cerebellar Purkinje cells (PCs), by immuno-gold electron microscopy, ASTN2 localizes primarily to endocytic and autophagocytic vesicles in the cell soma and in subsets of dendritic spines. Overexpression of ASTN2 in PCs, but not of ASTN2 lacking the FNIII-domain commonly disrupted by CNVs in patients including in a family presented here, increases inhibitory and excitatory postsynaptic activity and reduces levels of ASTN2 binding partners. Our data suggest a fundamental role for ASTN2 in dynamic regulation of surface proteins by endocytic trafficking and protein degradation.

scholarly journals Gestational Factors throughout Fetal Neurodevelopment: The Serotonin Link

2020 ◽  
Vol 21 (16) ◽  
pp. 5850 ◽  
Author(s):  
Sabrina I. Hanswijk ◽  
Marcia Spoelder ◽  
Ling Shan ◽  
Michel M. M. Verheij ◽  
Otto G. Muilwijk ◽  
...  
Keyword(s):  
Brain Development ◽  
Animal Studies ◽  
Fetal Brain ◽  
Neuropsychiatric Disorders ◽  
Autism Spectrum ◽  
Hyperactivity Disorder ◽  
Maternal Genotype ◽  
Brain Structure And Function ◽  
And Function ◽  
And Behavior

Serotonin (5-HT) is a critical player in brain development and neuropsychiatric disorders. Fetal 5-HT levels can be influenced by several gestational factors, such as maternal genotype, diet, stress, medication, and immune activation. In this review, addressing both human and animal studies, we discuss how these gestational factors affect placental and fetal brain 5-HT levels, leading to changes in brain structure and function and behavior. We conclude that gestational factors are able to interact and thereby amplify or counteract each other’s impact on the fetal 5-HT-ergic system. We, therefore, argue that beyond the understanding of how single gestational factors affect 5-HT-ergic brain development and behavior in offspring, it is critical to elucidate the consequences of interacting factors. Moreover, we describe how each gestational factor is able to alter the 5-HT-ergic influence on the thalamocortical- and prefrontal-limbic circuitry and the hypothalamo-pituitary-adrenocortical-axis. These alterations have been associated with risks to develop attention deficit hyperactivity disorder, autism spectrum disorders, depression, and/or anxiety. Consequently, the manipulation of gestational factors may be used to combat pregnancy-related risks for neuropsychiatric disorders.

Cell adhesion proteins and the pathogenesis of autism spectrum disorders

2015 ◽  
Vol 113 (5) ◽  
pp. 1283-1286 ◽  
Author(s):  
Luke T. Stewart
Keyword(s):  
Autism Spectrum Disorders ◽  
Cell Adhesion ◽  
Hippocampal Slices ◽  
Autism Spectrum ◽  
Adhesion Proteins ◽  
Brain Circuits ◽  
Alternatively Spliced ◽  
Spectrum Disorders ◽  
Acute Hippocampal Slices ◽  
Cell Adhesion Proteins

Current theories on the pathogenesis of autism spectrum disorders (ASD) maintain that the associated cognitive and behavioral symptoms are caused by aberrant synaptic transmission affecting specific brain circuits. Transgenic mouse models have implicated the involvement of cell adhesion proteins in synaptic dysfunction and ASD pathogenesis. Recently, Aoto et al. ( Cell 154: 75–88, 2013) has shown that alternatively spliced neurexin proteins affect the efficacy of AMPA receptor-mediated excitatory currents in both cultured neuronal networks and acute hippocampal slices constituting a potential ASD-related electrophysiological phenotype.

scholarly journals Structure, Expression, and Function of ICAM-5

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Heping Yang
Keyword(s):  
Nervous System ◽  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Synapse Formation ◽  
The Other ◽  
Intercellular Adhesion Molecule ◽  
Cellular Functions ◽  
Binding Partners ◽  
The Central Nervous System ◽  
And Function

Cell adhesion is of utmost importance in normal development and cellular functions. ICAM-5 (intercellular adhesion molecule-5, telencephalin, TLN) is a member of the ICAM family of adhesion proteins. As a novel cell adhesion molecule, ICAM-5 shares many structural similarities with the other members of IgSF, especially the ICAM subgroup; however, ICAM-5 has several unique properties compared to the other ICAMs. With its nine extracellular Ig domains, ICAM-5 is the largest member of ICAM subgroup identified so far. Therefore, it is much more complex than the other ICAMs. The expression of ICAM-5 is confined to the telencephalic neurons of the central nervous system whereas all the other ICAM members are expressed mostly by cells in the immune and blood systems. The developmental appearance of ICAM-5 parallels the time of dendritic elongation and branching, and synapse formation in the telencephalon. As a somatodendrite-specific adhesion molecule, ICAM-5 not only participates in immune-nervous system interactions, it could also participate in neuronal activity, Dendrites’ targeting signals, and cognition. It would not be surprising if future investigations reveal more binding partners and other related functions of ICAM-5.

scholarly journals Liprin-α-Mediated Assemblies and Their Roles in Synapse Formation

2021 ◽  
Vol 9 ◽  
Author(s):  
Xingqiao Xie ◽  
Mingfu Liang ◽  
Cong Yu ◽  
Zhiyi Wei
Keyword(s):  
Synapse Formation ◽  
Protein Complexes ◽  
Synaptic Proteins ◽  
Model Systems ◽  
Genetic Studies ◽  
Binding Partners ◽  
Assembly Mechanism ◽  
Cellular Junctions ◽  
Organized Assemblies ◽  
And Function

Brain’s functions, such as memory and learning, rely on synapses that are highly specialized cellular junctions connecting neurons. Functional synapses orchestrate the assembly of ion channels, receptors, enzymes, and scaffold proteins in both pre- and post-synapse. Liprin-α proteins are master scaffolds in synapses and coordinate various synaptic proteins to assemble large protein complexes. The functions of liprin-αs in synapse formation have been largely uncovered by genetic studies in diverse model systems. Recently, emerging structural and biochemical studies on liprin-α proteins and their binding partners begin to unveil the molecular basis of the synaptic assembly. This review summarizes the recent structural findings on liprin-αs, proposes the assembly mechanism of liprin-α-mediated complexes, and discusses the liprin-α-organized assemblies in the regulation of synapse formation and function.

scholarly journals Molecular Mechanisms of Environmental Metal Neurotoxicity: A Focus on the Interactions of Metals with Synapse Structure and Function

Toxics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 198
Author(s):  
Asuncion Carmona ◽  
Stéphane Roudeau ◽  
Richard Ortega
Keyword(s):  
Environmental Exposure ◽  
Molecular Mechanisms ◽  
Neurological Diseases ◽  
Autism Spectrum ◽  
Structure And Function ◽  
Synaptic Proteins ◽  
Health Concern ◽  
Synaptic Structure ◽  
Cadmium Lead ◽  
And Function

Environmental exposure to neurotoxic metals and metalloids such as arsenic, cadmium, lead, mercury, or manganese is a global health concern affecting millions of people worldwide. Depending on the period of exposure over a lifetime, environmental metals can alter neurodevelopment, neurobehavior, and cognition and cause neurodegeneration. There is increasing evidence linking environmental exposure to metal contaminants to the etiology of neurological diseases in early life (e.g., autism spectrum disorder) or late life (e.g., Alzheimer’s disease). The known main molecular mechanisms of metal-induced toxicity in cells are the generation of reactive oxygen species, the interaction with sulfhydryl chemical groups in proteins (e.g., cysteine), and the competition of toxic metals with binding sites of essential metals (e.g., Fe, Cu, Zn). In neurons, these molecular interactions can alter the functions of neurotransmitter receptors, the cytoskeleton and scaffolding synaptic proteins, thereby disrupting synaptic structure and function. Loss of synaptic connectivity may precede more drastic alterations such as neurodegeneration. In this article, we will review the molecular mechanisms of metal-induced synaptic neurotoxicity.

Development of Neural Structure and Function in Autism Spectrum Disorder: Potential Implications for Learning Language

2020 ◽  
Vol 29 (4) ◽  
pp. 1783-1797
Author(s):  
Kelly L. Coburn ◽  
Diane L. Williams
Keyword(s):  
Autism Spectrum Disorder ◽  
Language Development ◽  
Diffusion Tensor ◽  
Autism Spectrum ◽  
Language Intervention ◽  
Spectrum Disorder ◽  
Autistic Children ◽  
Neural Structure ◽  
Complex Information ◽  
And Function

Purpose Neurodevelopmental processes that begin during gestation and continue throughout childhood typically support language development. Understanding these processes can help us to understand the disruptions to language that occur in neurodevelopmental conditions, such as autism spectrum disorder (ASD). Method For this tutorial, we conducted a focused literature review on typical postnatal brain development and structural and functional magnetic resonance imaging, diffusion tensor imaging, magnetoencephalography, and electroencephalography studies of the neurodevelopmental differences that occur in ASD. We then integrated this knowledge with the literature on evidence-based speech-language intervention practices for autistic children. Results In ASD, structural differences include altered patterns of cortical growth and myelination. Functional differences occur at all brain levels, from lateralization of cortical functions to the rhythmic activations of single neurons. Neuronal oscillations, in particular, could help explain disrupted language development by elucidating the timing differences that contribute to altered functional connectivity, complex information processing, and speech parsing. Findings related to implicit statistical learning, explicit task learning, multisensory integration, and reinforcement in ASD are also discussed. Conclusions Consideration of the neural differences in autistic children provides additional scientific support for current recommended language intervention practices. Recommendations consistent with these neurological findings include the use of short, simple utterances; repetition of syntactic structures using varied vocabulary; pause time; visual supports; and individualized sensory modifications.

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