Publications by authors named "Hey-Jin Lee"

Article Synopsis
  • Axonal degeneration from optic nerve damage can lead to the death of retinal ganglion cells (RGCs) and permanent vision loss; two methods, optic nerve compression (ONCo) and optic nerve crush (ONCr), were compared for their effectiveness in studying this damage.
  • Both ONCo and ONCr successfully induced optic nerve damage as indicated by increased ischemia and changes in genes associated with neuronal regeneration, with neural progenitor cell (NPC) treatments showing more recovery in ONCo.
  • Proteomic analysis identified important genes related to mitochondrial function and inflammation in R28 cells; NPCs promoted neuroprotection and managed inflammation, suggesting that cell-based therapies like NPCs could help treat optic neuropathies caused by ischemic or
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Background: Graves' ophthalmopathy (GO) is a disorder, in which orbital connective tissues get in inflammation and increase in volume. Stimulants such as thyroid-stimulating hormone (TSH), insulin-like growth factor 1(IGF-1), IL-1, interferon γ, and platelet-derived growth factor cause differentiation into adipocytes of orbital fibroblasts (OFs) in the orbital fat and extraocular muscles. Human placental mesenchymal stem cells (hPMSCs) are known to have immune modulation effects on disease pathogenesis.

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The anticancer effects of Shinan (Shinan-South Korea) sea salts on azoxymethane (AOM)/dextran sodium sulfate (DSS) with high fat diet (HFD)-induced colon cancer and obesity in C57BL/6N mice were studied. We prepared three types of sea salt: generally manufactured sea salt (GS), generally manufactured after filtering seawater (FS), and manufactured with only new seawater (NS). Sea salt intake increased colon length and reduced colon length/weight ratio, tumor number, and progression of colon cancer in colon tissue.

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14-3-3 is a family of highly conserved protein that is involved in a number of cellular processes. In this study, we identified that the high expression of 14-3-3γ in various cancer cell lines correlates with the invasiveness of the cancer cells. Overexpression of 14-3-3γ causes changes to the morphologic characteristics of cell transformation, and promotes cell migration and invasion.

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Isolation of induced pluripotent stem cells (iPSCs) from fully differentiated somatic cells has revolutionized existing concepts of cell differentiation and stem cells. Importantly, iPSCs generated from somatic cells of patients can be used to model different types of human diseases. They may also serve as autologous cell sources that can be used in transplantation therapy.

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In general, the formation of embryoid bodies (EBs) is a commonly known method for initial induction of human embryonic stem cells (hESCs) into their derivatives in vitro. Despite the ability of EBs to mimic developmental processing, the specification and classifications of EBs are not yet well known. Because EBs show various differentiation potentials depending on the size and morphology of the aggregated cells, specification is difficult to attain.

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SDS3 is a key component of the histone deacetylase (HDAC)-dependent Sin3A co-repressor complex, serving to maintain its HDAC activity. Here, we report both exogenous and endogenous functional interaction between deubiquitinating enzyme USP17 and human SDS3 by MALDI-TOF-MS, co-immunoprecipitation assay, and GST pull-down assay. In this study, we demonstrated that SDS3 readily undergoes endogenous polyubiquitination, which is associated specifically with Lys-63-branched polyubiquitin chains and not with Lys-48-branched polyubiquitin chains.

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Translational studies have explored the therapeutic effects of stem cells, raising hopes for the treatment of numerous diseases. Here, we evaluated the therapeutic effect of chorionic plate-derived mesenchymal stem cells (CP-MSCs) isolated from human placenta and transplanted into rats with carbon tetrachloride (CCl(4))-injured livers. CP-MSCs were analyzed for hepatocyte-specific gene expression, indocyanine green (ICG) uptake, glycogen storage, and urea production following hepatogenic differentiation.

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Cell-cell interactions between muscle precursors are required for myogenic differentiation; however, underlying mechanisms are largely unknown. Promyogenic cell surface protein Cdo functions as a component of multiprotein complexes containing other cell adhesion molecules, Boc, Neogenin and N-cadherin, and mediates some of signals triggered by cell-cell interactions between muscle precursors. Cdo activates p38MAPK via interaction with two scaffold proteins JLP and Bnip-2 to promote myogenesis.

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In regulation of the developmental process, the balance between cellular proliferation and cell death is critical. Placental development tightly controls this mechanism, and increased apoptosis of placental trophoblasts can cause a variety of gynecological diseases. Members of the immortalization-upregulated protein (IMUP) family are nuclear proteins implicated in SV40-mediated immortalization and cellular proliferation; however, the mechanisms by which their expression is regulated in placental development are still unknown.

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Ubiquitination and deubiquitination have a critical role in protein homoeostasis in the cell. Here, we have characterized a novel USP44 (ubiquitin-specific protease 44), which has a ZnF-UBP (zinc-finger ubiquitin-specific protease) domain and conserved cysteine, histidine and asparagine/aspartic acid residues characteristic of deubiquitinating enzymes. The biochemical assay revealed that USP44 can cleave ubiquitin from ubiquitinated substrates both in vitro and in vivo.

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The establishment of new technology for genetic modification in human embryonic stem (ES) cell lines has raised great hopes for achieving new ground in basic and clinical research. Recently, lentiviral vector technology has been shown to be highly effective and therefore could emerge as a popular tool for human ES cell genetic modification. The objectives of this study were to evaluate the efficiency of promoters in lentiviral gene delivery systems in mammalian ES cells, including mouse, monkey, and human, and to construct efficient and optimized conditions for lentivirus-mediated transfection systems.

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Mouse Usp42, a novel ubiquitin specific protease gene, was isolated from mouse embryonic stem cells. It consists of 1,324 amino acids with a predicted molecular weight of 146kDa and contains the conserved Cys, Asp (I), His and Asn/Asp (II) domains defined as one of characteristics for deubiquitinating enzymes. RT-PCR analysis showed that the Usp42 transcript is expressed in NIH3T3 cells, B- and T-lymphocytes, and L1210 cells.

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Deubiquitinating enzymes regulate a number of cellular mechanisms including pre-implantation, growth and differentiation, oncogenesis, cell cycle progression, transcriptional activation, and signal transduction. In this study, we have identified a novel human deubiquitinating enzyme gene, USP22, and its mouse homologue, Usp22. They encode 525 amino acids (approximate MW: 60kDa) and contains Cys, Asp (I), His and Asp/Asn (II), the highly conserved domains of the UBP family of deubiquitinating enzymes.

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Platelet-derived growth factor (PDGF) has multiple functions including inhibition of apoptosis and promotion of cell proliferation. In this study, we show that Na(+)/H(+) exchanger regulatory factor 2 (NHERF2) binds to the carboxyl-terminal PDZ domain-binding motif of the PDGF receptor through a PDZ domain-mediated interaction, and evaluate the consequence on PDGF-induced proliferation. Stable transfection with NHERF2 increased the PDGF-induced phosphorylation of ERK and Akt in Rat1 embryonic fibroblasts.

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