Publications by authors named "Ji-Yoen Kim"

Accumulation of α-Synuclein (α-Syn) causes Parkinson's disease (PD) as well as other synucleopathies. α-Syn is the major component of Lewy bodies and Lewy neurites, the proteinaceous aggregates that are a hallmark of sporadic PD. In familial forms of PD, mutations or copy number variations in (the α-Syn gene) result in a net increase of its protein levels.

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  • Alzheimer's and Parkinson's diseases involve harmful proteins like tau and α-synuclein, requiring long-term treatments to manage their effects.
  • Research has indicated that TRIM28 plays a role in controlling the levels and toxicity of these proteins, but its mechanisms and safety of long-term inhibition were unclear.
  • The study found that reducing TRIM28 in adult mice does not cause negative behavioral or health issues and actually lowers the levels of α-Syn and tau, suggesting that inhibiting TRIM28 in adults could be a promising strategy to manage these neurodegenerative diseases.
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Previous studies suggested that MeCP2 competes with linker histone H1, but this hypothesis has never been tested in vivo. Here, we performed chromatin immunoprecipitation followed by sequencing (ChIP-seq) of Flag-tagged-H1.0 in mouse forebrain excitatory neurons.

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  • Gain-of-function mutations in certain genes can lead to neurodegenerative diseases, while loss-of-function mutations in the same genes create different effects; ATXN1 protein involvement is a key example.
  • The study reveals that the ATXN1-CIC complex is crucial for survival and brain development, as its absence can lead to hyperactivity, learning difficulties, and abnormal neuron development.
  • Researchers identified individuals with specific mutations in CIC showing patterns of intellectual disability, ADHD, and autism, indicating that the loss of ATXN1-CIC complexes results in a range of neurobehavioral issues.
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Four mutations in the VAMP/synaptobrevin-associated protein B (VAPB) gene have been linked to amyotrophic lateral sclerosis (ALS) type 8. The mechanism by which VAPB mutations cause motor neuron disease is unclear, but studies of the most common P56S variant suggest both loss of function and dominant-negative sequestration of wild-type protein. Diminished levels of VAPB and its proteolytic cleavage fragment have also been reported in sporadic ALS cases, suggesting that VAPB loss of function may be a common mechanism of disease.

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The rapid pace of neuroscience research demands equally efficient and flexible methods for genetically manipulating and visualizing selected neurons within the rodent brain. The use of viral vectors for gene delivery saves the time and cost of traditional germline transgenesis and offers the versatility of readily available reagents that can be easily customized to meet individual experimental needs. Here, we present a protocol for widespread neuronal transduction based on intraventricular viral injection of the neonatal mouse brain.

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Spinocerebellar ataxia type 1 (SCA1) is a paradigmatic neurodegenerative proteinopathy, in which a mutant protein (in this case, ATAXIN1) accumulates in neurons and exerts toxicity; in SCA1, this process causes progressive deterioration of motor coordination. Seeking to understand how post-translational modification of ATAXIN1 levels influences disease, we discovered that the RNA-binding protein PUMILIO1 (PUM1) not only directly regulates ATAXIN1 but also plays an unexpectedly important role in neuronal function. Loss of Pum1 caused progressive motor dysfunction and SCA1-like neurodegeneration with motor impairment, primarily by increasing Ataxin1 levels.

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With the pace of scientific advancement accelerating rapidly, new methods are needed for experimental neuroscience to quickly and easily manipulate gene expression in the mouse brain. Here we describe a technique first introduced by Passini and Wolfe for direct intracranial delivery of virally-encoded transgenes into the neonatal mouse brain. In its most basic form, the procedure requires only an ice bucket and a microliter syringe.

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Alzheimer's disease (AD) is associated with an elevated risk for seizures that may be fundamentally connected to cognitive dysfunction. Supporting this link, many mouse models for AD exhibit abnormal electroencephalogram (EEG) activity in addition to the expected neuropathology and cognitive deficits. Here, we used a controllable transgenic system to investigate how network changes develop and are maintained in a model characterized by amyloid β (Aβ) overproduction and progressive amyloid pathology.

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Article Synopsis
  • AAV-mediated gene expression is effective for gene therapy, but specific analysis in neonatal rodents is lacking.
  • Research shows that the timing of AAV injection significantly affects the distribution and type of cell transduced; injections on the first day produce mainly neuronal transduction, while later injections lead to more non-neuronal transduction.
  • AAV2/8 and AAV2/9 provide the broadest distribution in the brain, and AAV2/5 consistently targets astrocytes, underlining the importance of selecting the right capsid serotype and timing for effective gene therapy.
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Background: Various biologic mediators, including matrix metalloproteinases (MMPs), that are implicated in periodontal tissue breakdown can be induced by cytokines. MMPs are known to degrade periodontal ligament attachment, and bone matrix proteins and tissue inhibitors of metalloproteinase (TIMPs) inhibit the activity of MMPs. The aim of this study is to investigate the effect of tumor necrosis factor (TNF)-α on the expression of MMPs in human periodontal ligament (PDL) cells in vitro and establish which MMPs are expressed specifically in response to that stimulus.

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Introduction: The purpose of this study was to investigate whether in vitro stimulation of pulp cells leads to increased secretion of matrix metalloproteinases (MMPs) and, if so, to identify which MMPs are affected.

Methods: Cells cultured from dental pulp were stimulated with tumor necrosis factor-α (TNF-α) (10 ng/mL) for 24 hours, and lysates were analyzed with an antibody array (Bio-Rad Laboratories, Hercules, CA). The mRNA and protein levels of MMP-3, -10, and -13 were measured by real-time polymerase chain reaction (real-time PCR), enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and zymography.

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The neonatal intraventricular injection of adeno-associated virus has been shown to transduce neurons widely throughout the brain, but its full potential for experimental neuroscience has not been adequately explored. We report a detailed analysis of the method's versatility with an emphasis on experimental applications where tools for genetic manipulation are currently lacking. Viral injection into the neonatal mouse brain is fast, easy, and accesses regions of the brain including the cerebellum and brainstem that have been difficult to target with other techniques such as electroporation.

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The phosphorylation state of large-conductance calcium-activated potassium (BK(Ca)) channels regulates their activity and is dynamically regulated by protein phosphatases and kinases, including protein kinase C (PKC). In this study, we showed that PKC activators up-regulate the activity of the BK(Ca) channel alpha (alpha)-subunit, Slo1, in cell-attached patches of transfected COS7 cells. In an immune complex kinase assay, BK(Ca) channels isolated from rat brain were phosphorylated in the presence of PKC activators, without the addition of exogenous PKC, which suggests that PKC and BK(Ca) channels functionally interact in vivo.

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A 13-yr-old female was admitted to our hospital with fever, seizure, and cervical lymphadenopathy. Laboratory data showed pancytopenia, elevation of serum transaminase, lactate dehydrogenase, triglyceride, and ferritin levels. Lymph node biopsy revealed features of Kikuchi's disease and there were signs of histiocytosis and hemophagocytic phenomenon in bone marrow.

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