scholarly journals Connecting the Neurobiology of Developmental Brain Injury: Neuronal Arborisation as a Regulator of Dysfunction and Potential Therapeutic Target

2021 ◽  
Vol 22 (15) ◽  
pp. 8220
Author(s):  
Ane Goikolea-Vives ◽  
Helen B. Stolp
Keyword(s):  
Neurodevelopmental Disorders ◽  
Synapse Formation ◽  
Neurodevelopmental Disorder ◽  
Therapeutic Benefit ◽  
Normal Brain ◽  
Environmental Pressures ◽  
Axon Extension ◽  
Neurodevelopmental Disease ◽  
Normal Brain Function ◽  
Pharmacological Modification

Neurodevelopmental disorders can derive from a complex combination of genetic variation and environmental pressures on key developmental processes. Despite this complex aetiology, and the equally complex array of syndromes and conditions diagnosed under the heading of neurodevelopmental disorder, there are parallels in the neuropathology of these conditions that suggest overlapping mechanisms of cellular injury and dysfunction. Neuronal arborisation is a process of dendrite and axon extension that is essential for the connectivity between neurons that underlies normal brain function. Disrupted arborisation and synapse formation are commonly reported in neurodevelopmental disorders. Here, we summarise the evidence for disrupted neuronal arborisation in these conditions, focusing primarily on the cortex and hippocampus. In addition, we explore the developmentally specific mechanisms by which neuronal arborisation is regulated. Finally, we discuss key regulators of neuronal arborisation that could link to neurodevelopmental disease and the potential for pharmacological modification of arborisation and the formation of synaptic connections that may provide therapeutic benefit in the future.

scholarly journals Early construction of the thalamocortical axon pathway requires JNK signaling within the ventral forebrain

2021 ◽  
Author(s):  
Jessica G Cunningham ◽  
James D Scripter ◽  
Stephany A Nti ◽  
Eric S Tucker
Keyword(s):  
Internal Capsule ◽  
Normal Brain ◽  
Axon Pathfinding ◽  
Long Distance ◽  
Jnk Signaling ◽  
Axon Extension ◽  
Thalamocortical Axons ◽  
Normal Brain Function ◽  
Important Pathway ◽  
Jnk Signaling Pathway

Thalamocortical connectivity is essential for normal brain function. This important pathway is established during development, when thalamic axons extend a long distance through the forebrain before reaching the cerebral cortex. In this study, we identify a novel role for the c-Jun N-terminal Kinase (JNK) signaling pathway in guiding thalamocortical axons through intermediate target territories. Complete genetic removal of JNK signaling from the Distal-less 5/6 (Dlx5/6) domain in mice prevents thalamocortical axons from crossing the diencephalon-telencephalon boundary (DTB) and the internal capsule fails to form. Ventral telencephalic cells critical for thalamocortical axon extension including corridor and guidepost neurons are also disrupted. In addition, corticothalamic, striatonigral, and nigrostriatal axons fail to cross the DTB. Analyses of different JNK mutants demonstrates that thalamocortical axon pathfinding has a non-autonomous requirement for JNK signaling. We conclude that JNK signaling within the Dlx5/6 territory enables the construction of major axonal pathways in the developing forebrain.

scholarly journals No Longer Underappreciated: The Emerging Concept of Astrocyte Heterogeneity in Neuroscience

2020 ◽  
Vol 10 (3) ◽  
pp. 168 ◽  
Author(s):  
Francisco Pestana ◽  
Gabriela Edwards-Faret ◽  
T. Grant Belgard ◽  
Araks Martirosyan ◽  
Matthew G. Holt
Keyword(s):  
Brain Function ◽  
Synapse Formation ◽  
Normal Brain ◽  
Barrier Formation ◽  
Astrocyte Heterogeneity ◽  
Normal Brain Function ◽  
The Central Nervous System ◽  
And Function ◽  
And Control

Astrocytes are ubiquitous in the central nervous system (CNS). These cells possess thousands of individual processes, which extend out into the neuropil, interacting with neurons, other glia and blood vessels. Paralleling the wide diversity of their interactions, astrocytes have been reported to play key roles in supporting CNS structure, metabolism, blood-brain-barrier formation and control of vascular blood flow, axon guidance, synapse formation and modulation of synaptic transmission. Traditionally, astrocytes have been studied as a homogenous group of cells. However, recent studies have uncovered a surprising degree of heterogeneity in their development and function, in both the healthy and diseased brain. A better understanding of astrocyte heterogeneity is urgently needed to understand normal brain function, as well as the role of astrocytes in response to injury and disease.

scholarly journals Cranial index of children with normal and abnormal brain development in Sokoto, Nigeria: A comparative study

2014 ◽  
Vol 5 (02) ◽  
pp. 139-143 ◽  
Author(s):  
Muhammad Awwal Musa ◽  
Abdullahi Daudu Zagga ◽  
Mohammed Danfulani ◽  
Aziz Abdo Tadros ◽  
Ahmed Hamid
Keyword(s):  
Comparative Study ◽  
Brain Development ◽  
Neurodevelopmental Disorders ◽  
Neurodevelopmental Disorder ◽  
Head Length ◽  
Head Width ◽  
Normal Brain ◽  
Anatomical Landmarks ◽  
Cranial Index ◽  
Abnormal Brain

ABSTRACT Background: Abnormal brain development due to neurodevelopmental disorders in children has always been an important concern, but yet has to be considered as a significant public health problem, especially in the low- and middle-income countries including Nigeria. Aims: The aim of this study is to determine whether abnormal brain development in the form of neurodevelopmental disorders causes any deviation in the cranial index of affected children. Materials and Methods: This is a comparative study on the head length, head width, and cranial index of 112 children (72 males and 40 females) diagnosed with at least one abnormal problem in brain development, in the form of a neurodevelopmental disorder (NDD), in comparison with that of 218 normal growing children without any form of NDD (121 males and 97 females), aged 0-18 years old seen at the Usmanu Danfodiyo University Teaching Hospital, Sokoto, over a period of six months, June to December, 2012. The head length and head width of the children was measured using standard anatomical landmarks and cranial index calculated. The data obtained was entered into the Microsoft excel worksheet and analyzed using SPSS version 17. Results: The mean Cephalic Index for normal growing children with normal brain development was 79.82 ± 3.35 and that of the children with abnormal brain development was 77.78 ± 2.95 and the difference between the two groups was not statistically significant (P < 0.05). Conclusion: It can be deduced from this present study that the cranial index does not change in children with neurodevelopmental disorders.

scholarly journals Tau and spectraplakins promote synapse formation and maintenance through Jun kinase and neuronal trafficking

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Andre Voelzmann ◽  
Pilar Okenve-Ramos ◽  
Yue Qu ◽  
Monika Chojnowska-Monga ◽  
Manuela del Caño-Espinel ◽  
...  
Keyword(s):  
Brain Function ◽  
Synapse Formation ◽  
Synaptic Proteins ◽  
Normal Brain ◽  
Synapse Loss ◽  
Jun Kinase ◽  
Regulatory Cascade ◽  
Microtubule Stability ◽  
Normal Brain Function ◽  
Synapse Maintenance

The mechanisms regulating synapse numbers during development and ageing are essential for normal brain function and closely linked to brain disorders including dementias. Using Drosophila, we demonstrate roles of the microtubule-associated protein Tau in regulating synapse numbers, thus unravelling an important cellular requirement of normal Tau. In this context, we find that Tau displays a strong functional overlap with microtubule-binding spectraplakins, establishing new links between two different neurodegenerative factors. Tau and the spectraplakin Short Stop act upstream of a three-step regulatory cascade ensuring adequate delivery of synaptic proteins. This cascade involves microtubule stability as the initial trigger, JNK signalling as the central mediator, and kinesin-3 mediated axonal transport as the key effector. This cascade acts during development (synapse formation) and ageing (synapse maintenance) alike. Therefore, our findings suggest novel explanations for intellectual disability in Tau deficient individuals, as well as early synapse loss in dementias including Alzheimer’s disease.

scholarly journals Interferon-ɣ Exposure of Human iPSC-derived Neurons Alters Major Histocompatibility Complex I and Synapsin I Protein Expression

2021 ◽  
Author(s):  
Adam Pavelinek ◽  
Rugile Matuleviciute ◽  
Laura Sichlinger ◽  
Lucia Dutan Polit ◽  
Nikos Armeniakos ◽  
...  
Keyword(s):  
Immune Activation ◽  
Neurodevelopmental Disorders ◽  
Synapse Formation ◽  
Neurodevelopmental Disorder ◽  
Synaptic Proteins ◽  
Synapsin I ◽  
Mrna Levels ◽  
Maternal Immune Activation ◽  
Increased Risk

Human epidemiological data links maternal immune activation during gestation with increased risk for neurodevelopmental disorders including schizophrenia. Animal models of maternal immune activation (MIA) provide causal evidence for this association and strongly suggest that inflammatory cytokines act is a critical link between maternal infection and aberrant offspring brain and behavior development. This includes evidence for reduced synapse formation, consistent with post-mortem and in vivo evidence of reduced synaptic density in schizophrenia. However, to what extent specific cytokines are necessary and sufficient for these effects remains unclear. Using a human cellular model, we recently demonstrated that acute exposure to interferon-ɣ (IFNɣ) recapitulates molecular and cellular phenotypes associated with neurodevelopmental disorders. Here, we extend this work to test whether IFNɣ affects synapse formation in an induced neuron model that generates forebrain glutamatergic neurons. Using immunocytochemistry and quantitative PCR, we demonstrate that acute IFNɣ exposure results in significantly increased MHCI expression at the mRNA and protein level. Furthermore, acute IFNɣ exposure decreases synapsin I protein in neurons but does not affect synaptic gene mRNA levels. Interestingly, complement component 4A (C4A) mRNA is also significantly increased following acute IFNɣ exposure. This study builds on our previous work by showing that IFNɣ-mediated disruption of relevant synaptic proteins can occur at early stages of synapse formation, potentially contributing to neurodevelopmental disorder phenotypes such as schizophrenia.

scholarly journals New Players Tip the Scales in the Balance between Excitatory and Inhibitory Synapses

2005 ◽  
Vol 1 ◽  
pp. 1744-8069-1-12 ◽  
Author(s):  
Joshua N Levinson ◽  
Alaa El-Husseini
Keyword(s):  
Brain Function ◽  
Single Neuron ◽  
Neuronal Excitability ◽  
Synapse Formation ◽  
Inhibitory Synapses ◽  
Normal Brain ◽  
Signaling Proteins ◽  
Tight Control ◽  
Normal Brain Function

Synaptogenesis is a highly controlled process, involving a vast array of players which include cell adhesion molecules, scaffolding and signaling proteins, neurotransmitter receptors and proteins associated with the synaptic vesicle machinery. These molecules cooperate in an intricate manner on both the pre- and postsynaptic sides to orchestrate the precise assembly of neuronal contacts. This is an amazing feat considering that a single neuron receives tens of thousands of synaptic inputs but virtually no mismatch between pre- and postsynaptic components occur in vivo. One crucial aspect of synapse formation is whether a nascent synapse will develop into an excitatory or inhibitory contact. The tight control of a balance between the types of synapses formed regulates the overall neuronal excitability, and is thus critical for normal brain function and plasticity. However, little is known about how this balance is achieved. This review discusses recent findings which provide clues to how neurons may control excitatory and inhibitory synapse formation, with focus on the involvement of the neuroligin family and PSD-95 in this process.

A Survey on Detection and Classification of Brain Tumor Using Image Processing Techniques

2020 ◽  
pp. 967-973
Author(s):  
V. Deepika ◽  
T. Rajasenbagam
Keyword(s):  
Image Processing ◽  
Brain Tumor ◽  
Soft Tissues ◽  
Tumor Detection ◽  
Tumor Classification ◽  
Normal Brain ◽  
Image Processing Techniques ◽  
Normal Brain Function ◽  
Processing Techniques ◽  
The Brain

A brain tumor is an uncontrolled growth of abnormal brain tissue that can interfere with normal brain function. Although various methods have been developed for brain tumor classification, tumor detection and multiclass classification remain challenging due to the complex characteristics of the brain tumor. Brain tumor detection and classification are one of the most challenging and time-consuming tasks in the processing of medical images. MRI (Magnetic Resonance Imaging) is a visual imaging technique, which provides a information about the soft tissues of the human body, which helps identify the brain tumor. Proper diagnosis can prevent a patient's health to some extent. This paper presents a review of various detection and classification methods for brain tumor classification using image processing techniques.

Possibility that the Onset of Autism Spectrum Disorder is Induced by Failure of the Glutamine-Glutamate Cycle

2020 ◽  
Vol 14 (2) ◽  
pp. 170-174
Author(s):  
Koichi Kawada ◽  
Nobuyuki Kuramoto ◽  
Seisuke Mimori
Keyword(s):  
Autism Spectrum Disorder ◽  
Endoplasmic Reticulum ◽  
Environmental Factors ◽  
Endoplasmic Reticulum Stress ◽  
Synapse Formation ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Neurodevelopmental Disease ◽  
Number Of Patients ◽  
The Brain

: Autism spectrum disorder (ASD) is a neurodevelopmental disease, and the number of patients has increased rapidly in recent years. The causes of ASD involve both genetic and environmental factors, but the details of causation have not yet been fully elucidated. Many reports have investigated genetic factors related to synapse formation, and alcohol and tobacco have been reported as environmental factors. This review focuses on endoplasmic reticulum stress and amino acid cycle abnormalities (particularly glutamine and glutamate) induced by many environmental factors. In the ASD model, since endoplasmic reticulum stress is high in the brain from before birth, it is clear that endoplasmic reticulum stress is involved in the development of ASD. On the other hand, one report states that excessive excitation of neurons is caused by the onset of ASD. The glutamine-glutamate cycle is performed between neurons and glial cells and controls the concentration of glutamate and GABA in the brain. These neurotransmitters are also known to control synapse formation and are important in constructing neural circuits. Theanine is a derivative of glutamine and a natural component of green tea. Theanine inhibits glutamine uptake in the glutamine-glutamate cycle via slc38a1 without affecting glutamate; therefore, we believe that theanine may prevent the onset of ASD by changing the balance of glutamine and glutamate in the brain.

scholarly journals LSD1 enzyme inhibitor TAK-418 unlocks aberrant epigenetic machinery and improves autism symptoms in neurodevelopmental disorder models

2021 ◽  
Vol 7 (11) ◽  
pp. eaba1187
Author(s):  
Rina Baba ◽  
Satoru Matsuda ◽  
Yuuichi Arakawa ◽  
Ryuji Yamada ◽  
Noriko Suzuki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Neurodevelopmental Disorders ◽  
Neurodevelopmental Disorder ◽  
Specific Inhibitor ◽  
Autism Spectrum ◽  
Poly I:C ◽  
Control Of Gene Expression ◽  
Epigenetic Machinery ◽  
The Brain

Persistent epigenetic dysregulation may underlie the pathophysiology of neurodevelopmental disorders, such as autism spectrum disorder (ASD). Here, we show that the inhibition of lysine-specific demethylase 1 (LSD1) enzyme activity normalizes aberrant epigenetic control of gene expression in neurodevelopmental disorders. Maternal exposure to valproate or poly I:C caused sustained dysregulation of gene expression in the brain and ASD-like social and cognitive deficits after birth in rodents. Unexpectedly, a specific inhibitor of LSD1 enzyme activity, 5-((1R,2R)-2-((cyclopropylmethyl)amino)cyclopropyl)-N-(tetrahydro-2H-pyran-4-yl)thiophene-3-carboxamide hydrochloride (TAK-418), almost completely normalized the dysregulated gene expression in the brain and ameliorated some ASD-like behaviors in these models. The genes modulated by TAK-418 were almost completely different across the models and their ages. These results suggest that LSD1 enzyme activity may stabilize the aberrant epigenetic machinery in neurodevelopmental disorders, and the inhibition of LSD1 enzyme activity may be the master key to recover gene expression homeostasis. TAK-418 may benefit patients with neurodevelopmental disorders.

scholarly journals Type IIa RPTPs and Glycans: Roles in Axon Regeneration and Synaptogenesis

2021 ◽  
Vol 22 (11) ◽  
pp. 5524
Author(s):  
Kazuma Sakamoto ◽  
Tomoya Ozaki ◽  
Yuji Suzuki ◽  
Kenji Kadomatsu
Keyword(s):  
Heparan Sulfate ◽  
Network Formation ◽  
Synapse Formation ◽  
Axon Regeneration ◽  
Transmembrane Protein ◽  
Inhibitory Synapses ◽  
Dependent Manner ◽  
Axon Terminals ◽  
Axon Extension ◽  
Receptor Tyrosine Phosphatases

Type IIa receptor tyrosine phosphatases (RPTPs) play pivotal roles in neuronal network formation. It is emerging that the interactions of RPTPs with glycans, i.e., chondroitin sulfate (CS) and heparan sulfate (HS), are critical for their functions. We highlight here the significance of these interactions in axon regeneration and synaptogenesis. For example, PTPσ, a member of type IIa RPTPs, on axon terminals is monomerized and activated by the extracellular CS deposited in neural injuries, dephosphorylates cortactin, disrupts autophagy flux, and consequently inhibits axon regeneration. In contrast, HS induces PTPσ oligomerization, suppresses PTPσ phosphatase activity, and promotes axon regeneration. PTPσ also serves as an organizer of excitatory synapses. PTPσ and neurexin bind one another on presynapses and further bind to postsynaptic leucine-rich repeat transmembrane protein 4 (LRRTM4). Neurexin is now known as a heparan sulfate proteoglycan (HSPG), and its HS is essential for the binding between these three molecules. Another HSPG, glypican 4, binds to presynaptic PTPσ and postsynaptic LRRTM4 in an HS-dependent manner. Type IIa RPTPs are also involved in the formation of excitatory and inhibitory synapses by heterophilic binding to a variety of postsynaptic partners. We also discuss the important issue of possible mechanisms coordinating axon extension and synapse formation.

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