• Molecules and Cells
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• v.39 no.10
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• pp.762-767
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• 2016

Fasciclin II (FasII), the Drosophila ortholog of neural cell adhesion molecule (NCAM), plays a critical role in synaptic stabilization and plasticity. Although this molecule undergoes constitutive cycling at the synaptic membrane, how its membrane trafficking is regulated to ensure proper synaptic development remains poorly understood. In a genetic screen, we recovered a mutation in Drosophila mical-like that displays an increase in bouton numbers and a decrease in FasII levels at the neuromuscular junction (NMJ). Similar phenotypes were induced by presynaptic, but not postsynaptic, knockdown of mical-like expression. FasII trafficking assays revealed that the recycling of internalized FasII molecules to the cell surface was significantly impaired in mical-like-knockdown cells. Importantly, this defect correlated with an enhancement of endosomal sorting of FasII to the lysosomal degradation pathway. Similarly, synaptic vesicle exocytosis was also impaired in mical-like mutants. Together, our results identify Mical-like as a novel regulator of synaptic growth and FasII endocytic recycling.

• Journal of Ginseng Research
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• v.48 no.2
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• pp.163-170
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• 2024

Background: Mechanisms of synaptic plasticity in retinal ganglion cells (RGCs) are complex and the current knowledge cannot explain. Growth and regeneration of dendrites together with synaptic formation are the most important parameters for evaluating the cellular protective effects of various molecules. The effect of ginsenoside Rg1 (Rg1) on the growth of retinal ganglion cell processes has been poorly understood. Therefore, we investigated the effect of ginsenoside Rg1 on the neurite growth of RGCs. Methods: Expression of proteins and mRNA were detected by Western blot and qPCR. cAMP levels were determined by ELISA. In vivo effects of Rg1 on RGCs were evaluated by hematoxylin and eosin, and immunohistochemistry staining. Results: This study found that Rg1 promoted the growth and synaptic plasticity of RGCs neurite by activating the cAMP/PKA/CREB pathways. Meanwhile, Rg1 upregulated the expression of GAP43, Rac1 and PAX6, which are closely related to the growth of neurons. Meantime, H89, an antagonist of PKA, could block this effect of Rg1. In addition, we preliminarily explored the effect of Rg1 on enhancing the glycolysis of RGCs, which could be one of the mechanisms for its neuroprotective effects. Conclusion: Rg1 promoted neurite growth of RGCs through cAMP/PKA/CREB pathways. This study may lay a foundation for its clinical use of optic nerve diseases in the future.

• PNF and Movement
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• v.6 no.2
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• pp.31-38
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• 2008

Purpose: The purpose of this study were to overview the effect of exercise on neural plasticity and the proteins related to neural plasticity. Results: Exercise increased levels of BDNF(brain-derived neurotrophic factor), Insulin-like growth factor-I (IGF-I), Synapsin, Synaptophysin, VEGF(vascular endothelial growth factor) and other growth factors, stimulate neurogenesis, increase resistance to brain insult and improve learning and mental performance. These proteins improved synaptic plasticity by directly affecting synaptic structure and potentiating synaptic strength, and by strengthening the underlying systems that support plasticity including neurogenesis, metabolism and vascular function. Conclusion: Exercise-induced structural and functional change by these proteins can effect on functional movement, cognition in healthy and brain injured people and animals.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.2
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• pp.117-125
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• 1997

The N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic neurotransmission is involved in synaptic plasticity, developmental processes, learning and memory and many neuropathological disorders including age-related diseases. In the present study, regulation of the NMDA receptor properties by various ligands was investigated using $[^3H]MK-801$ binding studies in the synaptic membranes of young and aged rat forebrains. The binding in the presence of glutamate and glycine increased dramatically with growth between 1 and 6 weeks old, and thereafter declined gradually with aging. Glutamate, glycine or spermine respectively increased the binding with growth. Glutamate maintained the binding during aging, while glycine or spermine significantly decreased the binding in the aged brain. The maximum stimulation by glycine varied depending on the ages of brains. Greater sensitivity to glycine was observed at 1 week and 3 months and the sensitivity was significantly reduced in the aged brain. In contrast, spermine showed similar stimulation patterns in young and aged rats. These results indicated that the functional properties of the NMDA receptor-ion channel complex in young and aged rat forebrains are differentially regulated by agonists, and the reduction of the receptor function with normal aging may be, in some degree, due to the reduction of the receptor sensitivity to glycine.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.77-81
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• 2004

The loss of neurons and synaptic contacts following cerebral ischemia may lead to a synaptic plastic modification, which may contribute to the functional recovery after a brain lesion. Using synapsin I and GAP-43 as markers, we investigated the neuronal cell death and the synaptic plastic modification in the rat hippocampus of a middle cerebral artery occlusion (MCAO) model. Cresyl violet staining revealed that neuronal cell damage occurred after 2 h of MCAO, which progressed during reperfusion for 2 weeks. The immunoreactivity of synapsin I and GAP-43 was increased in the stratum lucidum in the CA3 subfield as well as in the inner and outer molecular layers of dentate gyrus in the hippocampus at reperfusion for 2 weeks. The immunoreactivity of phosphosynapsin was increased in the stratum lucidum in the CA3 subfield during reperfusion for 1 week. Our data suggest that the increase in the synapsin I and GAP-43 immunoreactivity probably mediates either the functional adaptation of the neurons through reactive synaptogenesis from the pre-existing presynaptic nerve terminals or the structural remodeling of their axonal connections in the areas with ischemic loss of target cells. Furthermore, phosphosynapsin may play some role in the synaptic plastic adaptations before or during reactive synaptogenesis after the MCAO.

• BMB Reports
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• v.42 no.5
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• pp.239-244
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• 2009

New neurons are continually generated in the subgranular zone of the dentate gyrus and in the subventricular zone of the lateral ventricles of the adult brain. These neurons proliferate, differentiate, and become integrated into neuronal circuits, but how they are involved in brain function remains unknown. A deficit of adult hippocampal neurogenesis leads to defective spatial learning and memory, and the hippocampi in neuropsychiatric diseases show altered neurogenic patterns. Adult hippocampal neurogenesis is not only affected by external stimuli but also regulated by internal growth factors including BDNF, VEGF and IGF-1. These factors are implicated in a broad spectrum of pathophysiological changes in the human brain. Elucidation of the roles of such neurotropic factors should provide insight into how adult hippocampal neurogenesis is related to psychiatric disease and synaptic plasticity.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.131-137
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• 1999

Neurotrophic factors control the survival and differentiation in developing neurons, Furthermore, nut evidence suggests that neurotrophic factors promote the axonal growth and synaptic plasticity In the CNS. Research is currently being undertaken in order to determine whether members of the neurotrophic factor family have potential therapeutic roles in preventing and/or reducing the neuronal cell death and atrophy. This review summarizes the current knowledge of characterized neurotrophic factors including NGF, BDNF, NT-3, and NT-4/5.

• Clinical and Experimental Pediatrics
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• v.54 no.6
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• pp.241-245
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• 2011

Tuberous sclerosis complex (TSC) is a genetic multisystem disorder that results from mutations in the TSC1 or TSC2 genes, and is associated with hamartomas in several organs, including subependymal giant cell tumors. The neurological manifestations of TSC are particularly challenging and include infantile spasms, intractable epilepsy, cognitive disabilities, and autism. The TSC1- and TSC2-encoded proteins modulate cell function via the mammalian target of rapamycin (mTOR) signaling cascade, and are key factors in the regulation of cell growth and proliferation. The mTOR pathway provides an intersection for an intricate network of protein cascades that respond to cellular nutrition, energy levels, and growth factor stimulation. In the brain, TSC1 and TSC2 have been implicated in cell body size, dendritic arborization, axonal outgrowth and targeting, neuronal migration, cortical lamination, and spine formation. The mTOR pathway represents a logical candidate for drug targeting, because mTOR regulates multiple cellular functions that may contribute to epileptogenesis, including protein synthesis, cell growth and proliferation, and synaptic plasticity. Antagonism of the mTOR pathway with rapamycin and related compounds may provide new therapeutic options for TSC patients.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4137-4142
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• 2015

The zinc finger transcription factor EGR 1 has a role in controlling synaptic plasticity, wound repair, female reproductive capacity, inflammation, growth control, apoptosis and tumor progression. Recent studies mainly focused on its role in growth control and apoptosis, however, little is known about its role in epithelial-mesenchymal transition (EMT). Here, we aim to explore whether EGR 1 is involved in TGF-${\beta}1$-induced EMT in non-smallcell lung cancer cells. Transforming growth factor (TGF)-${\beta}1$ was utilized to induce EMT in this study. Western blotting, RT-PCR, and transwell chambers were used to identify phenotype changes. Western blotting was also used to observe changes of the expression of EGR 1. The lentivirus-mediated EGR 1 vector was used to increase EGR 1 expression. We investigated the change of migration to evaluate the effect of EGR 1 on non-small-cell lung cancer cells migration by transwell chambers. After stimulating with TGF-${\beta}1$, almost all A549 cells and Luca 1 cells (Non-small-cell lung cancer primary cells) changed to mesenchymal phenotype and acquired more migration capabilities. These cells also had lower EGR 1 protein expression. Overexpression of EGR 1 gene with EGR 1 vector could decrease tumor cell migration capabilities significantly after adding TGF-${\beta}1$. These data s howed an important role of EGR 1 in the EMT of non-small-cell lung cancer cells, as well as migration.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.19 no.2
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• pp.61-71
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• 2008

Attention-deficit hyperactivity disorder (ADHD) is characterized by inattention, hyperactivity, impulsiveness and problems in other higher cognitive processes such as executive function deficits. Currently, there are many treatment modalities, of which pharmacotherapy is the most strongly supported by scientific and clinical evidence. Stimulants, which are first choice in the pharmacological treatment of ADHD, block dopamine reuptake by binding the dopamine transporter and so increasing the concentration of dopamine in synaptic clefts. Stimulants are effective in improving core ADHD symptoms, as well as the nonspecific symptoms, such as aggressiveness and oppositional behavior. Frequently reported short-term adverse effects are decreased appetite, sleep disturbance, headache, dizziness and irritability. Although questions have been raised about the long-term side effects of stimulants, including growth suppression, cardiovascular events, and abuse potential, there is no clear evidence to support these concerns.