Publications by authors named "Myung-Kyu Lee"

Article Synopsis
  • - The study examines ACL reconstruction using tendon grafts, noting that healing leads to weaker scar tissue (type III collagen) rather than stronger, normal ACL tissue.
  • - Researchers tested the effect of compressive forces on ACL-derived cells reseeded into tendon grafts, finding that compression improved cell survival, integration, and gene expression of type I collagen.
  • - The results suggest that applying mechanical compression during the healing process may enhance the quality of tendon graft integration, potentially due to the role of Yes-associated protein (YAP) in promoting collagen production.
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Perilla meal hydrolysates (PMHs) were prepared by proteases; volatile profiles from heated mixtures of PMH and coconut oil (CO) were evaluated for their application as odor providers. Amino acids composition and degree of hydrolysis, and antioxidant activity in O/W emulsion of PMHs were assessed. PMHs were heated with different concentration of CO or with CO, xylose, and cysteine, which were non-Maillard and Maillard system, respectively.

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Purpose: Total kidney volume (TKV) measurement is crucial for selecting treatment candidates in autosomal dominant polycystic kidney disease (ADPKD). We developed and investigated the performance of fully-automated 3D-volumetry model and applied it to software as a service (SaaS) for clinical support on tolvaptan prescription in ADPKD patients.

Materials And Methods: Computed tomography scans of ADPKD patients taken between January 2000 and June 2022 were acquired from seven institutions.

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Aims: To test the hypothesis that reseeded anterior cruciate ligament (ACL)-derived cells have a better ability to survive and integrate into tendon extracellular matrix (ECM) and accelerate the ligamentization process, compared to adipose-derived mesenchymal stem cells (ADMSCs).

Methods: Acellularized tibialis allograft tendons were used. Tendons were randomly reseeded with ACL-derived cells or ADMSCs.

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The matrix protein 2 of influenza A virus (IFAV) has a relatively conserved ectodomain (M2e) composed of 23 amino acids, and M2e-based vaccines have been suggested to induce broad protective immunity in mice. In this study, we investigated whether N-terminal sequence of M2e (nM2e)-based vaccines with more conserved nM2e could induce influenza viral neutralizing activity. We constructed linear peptide vaccines with an nM2e sequence for PR8 virus (nM2Pr) connected to a probable 17-mer IFAV-derived helper T-cell epitope (ThE: T1, T2, or T3) at its N- or C-terminus.

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Hypoxia-inducible factor 1 (HIF-1) is a key player in cellular response to hypoxia. The stability and transcriptional activity of this protein are oxygen-dependently regulated by the prolyl hydroxylases PHD1-3 and the asparaginyl hydroxylase FIH. Recently, ferritin heavy chain (FTH1) has been characterized to reinforce the HIF-1 signaling pathway in an indirect way through the inhibition of PHD activity by depleting the free iron pool in the cytoplasm.

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Previously a scalable and extrusion-free method has been developed for efficient liposomal encapsulation of DNA by twice stepwise mixing of lipids in ethanol and DNA solution using T-shape mixing chamber. In this study, we prepared nanoliposomes encapsulating siRNA by simply discontinuous mixing of lipids in ethanol/ether/water mixture and acidic siRNA solution without use of special equipment. The simple mixing siRNA/liposomal particles (siRNA/SMLs) prepared using ethanol/ether/water (3:1:1) mixture showed 120.

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Agarose gel can be used for three dimensional (3D) cell culture because it prevents cell attachment. The dried agarose film coated on a culture plate also protected cell attachment and allowed 3D growth of cancer cells. We developed an efficient method for agarose film coating on an oxygen-plasma treated micropost polystyrene chip prepared by an injection molding process.

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Fc-specific antibody binding proteins (FcBPs) with the minimal domain of protein G are widely used for immobilization of well-oriented antibodies onto solid surfaces, but the noncovalently bound antibodies to FcBPs are unstable in sera containing large amounts of antibodies. Here we report novel photoactivatable FcBPs with photomethionine (pMet) expressed in E. coli, which induce Fc-specific photo-cross-linking with antibodies upon UV irradiation.

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This work demonstrates successful delivery of a gene to EGFR-overexpressed cancer cells by using a rationally designed branched GE11 peptide as a targeting ligand. In addition, we exploited the effect of the divalent structure of the branched GE11 peptide on the gene delivery and tumor targeting efficiency, compared to the monovalent GE11 peptide. The GE11 or branched GE11-tethered polymers were successfully synthesized.

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Myoglobin is an early biomarker for acute myocardial infarction. Recently, we isolated the antibody IgG-Myo2-7ds, which exhibits unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid dissociation kinetics are thought to be premature IgG forms that are produced during the early stage of in vivo immunization.

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Myoglobin is one of the early biomarkers for acute myocardial infarction. Recently, we have screened an antibody with unique rapid reaction kinetics toward human myoglobin antigen. Antibodies with rapid reaction kinetics are thought to be an early IgG form produced during early stage of in vivo immunization.

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Despite significant improvement in separation efficiency using nanostructure-based platforms, the mechanism underlying the high efficiency of rare cell capture remains elusive. Here we report on the first mechanistic study by developing highly controlled nanostructures to investigate cell surface nanomorphology to better understand the cellular response of CD4(+) T-lymphocytes in contact with nanostructured surfaces and to elucidate key mechanisms for enhancing separation efficiency. Our results showed that actin-rich filopodia protruded from T-cells in the early stage of cell capture (<20 min), demonstrate the different morphologies in response to various quartz nanopillar (QNP) arrays functionalized with streptavidin and the generation of sufficient adhesion sites for rendering more stable binding through three-dimensional local nanotopographic interactions between filopodia-QNPs and cell-substrate, leading to synergistic effects for enhancing cell-capture efficiency.

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Nanostructured surfaces emerge as a new class of material for capture and separation of cell populations including primary immune cells and disseminating rare tumor cells, but the underlying mechanism remains elusive. Although it has been speculated that nanoscale topological structures on cell surface are involved in the cell capture process, there are no studies that systematically analyze the relation between cell surface structures and the capture efficiency. Here we report on the first mechanistic study by quantifying the morphological parameters of cell surface nanoprotrusions, including filopodia, lamellipodia, and microvilli in the early stage of cell capture (< 20 min) in correlation to the efficiency of separating primary T lymphocytes.

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TMPRSS4 is a novel type II transmembrane serine protease that is highly expressed on the cell surface in pancreatic, thyroid, colon, and other cancer tissues. Previously, we demonstrated that TMPRSS4 mediates cancer cell invasion, epithelial-mesenchymal transition, and metastasis and that increased TMPRSS4 expression correlates with colorectal cancer progression. We also demonstrated that TMPRSS4 upregulates urokinase-type plasminogen activator (uPA) gene expression to induce cancer cell invasion.

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TMPRSS4 is a novel type II transmembrane serine protease that is highly expressed in pancreatic, thyroid, colon, and other cancer tissues. Previously, we demonstrated that TMPRSS4 mediates tumor cell invasion, migration, and metastasis. However, the mechanisms by which TMPRSS4 contributes to invasion are not fully understood.

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The hypoxia inducible factor (HIF) system is central to the signaling of low oxygen (hypoxia) in animals. The levels of HIF-α isoforms are regulated in an oxygen-dependent manner by the activity of the HIF prolyl-hydroxylases (PHD or EGLN enzymes), which are Fe(II) and 2-oxoglutarate (2OG) dependent oxygenases. Here, we describe biochemical, crystallographic, cellular profiling, and animal studies on PHD inhibitors including selectivity studies using a representative set of human 2OG oxygenases.

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Background: siRNA is a new tool for treatment of diseases such as cancer. However, it cannot be used directly due to rapid degradation in body fluid and blood stream; therefore, vectors are necessary for protection of siRNA against RNases and also for its precise delivery to the target cells. Since viral vector causes cancer and immune response in the host, liposomes are more preferable vectors.

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Cell penetrating peptides (CPPs) have been used to transport macromolecules into cells. Most CPPs have properties such as a strong polycationic charge, amphipathic basic, and hydrophobicity. In this study, we designed the peptides with multiple motifs composed of RGD and its analogs to induce integrin-mediated endocytosis as well as endosomal escape by forming an amphipathic helix in acidic endosomes.

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Inhibition of the hypoxia-inducible factor (HIF) prolyl hydroxylases (PHD or EGLN enzymes) is of interest for the treatment of anemia and ischemia-related diseases. Most PHD inhibitors work by binding to the single ferrous ion and competing with 2-oxoglutarate (2OG) co-substrate for binding at the PHD active site. Non-specific iron chelators also inhibit the PHDs, both in vitro and in cells.

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Hypoxia inducible factor 1α (HIF-1α), an essential transcriptional factor, is negatively regulated by two different types of oxygen and Fe(2+) -dependent HIF hydroxylases, proline hydroxylase (PHD) and factor inhibiting HIF (FIH), under normoxia. Iron chelators have therefore been used for inducing HIF-1α expression by inhibiting the hydroxylases. In this study, the iron chelators displayed differential effects for PHD and FIH in cells depending on their iron specificity and membrane permeability rather than their in vitro potencies.

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The discovery of siRNA has been an important step in gene therapy, but the problem of delivering siRNA to a target organ limits its use as a therapeutic drug. Liposomes can be used as a nonviral vector to deliver siRNA to target cells. In this study we developed a novel method of producing asymmetric liposome particles (ALPs) with highly efficient siRNA encapsulation.

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Hypoxia inducible factor (HIF) is regulated by dual pathways involving oxygen-dependent prolyl and asparaginyl hydroxylation of its α-subunits. Prolyl hydroxylation at two sites within a central degradation domain promotes association of HIF-α with the von Hippel-Lindau ubiquitin E3 ligase and destruction by the ubiquitin-proteasome pathways. Asparaginyl hydroxylation blocks the recruitment of p300/CBP co-activators to a C-terminal activation domain in HIF-α.

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Hypoxia-inducible factor HIF-1 is responsible for radiation resistance and poor prognosis in cancer therapy. As part of our drug discovery program, a novel HIF inhibitor, LW6, was identified as a small compound that inhibits the accumulation of HIF-1alpha. We found that LW6 decreased HIF-1alpha protein expression without affecting HIF-1beta expression.

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The inhibitors of factor-inhibiting HIF-1 (FIH1) have been shown to be useful as therapeutics for the treatment of anemia. We have been able to identify eight novel FIH1 inhibitors with IC(50) values ranging from 30 to 80microM by means of the virtual screening with docking simulations under consideration of the effects of ligand solvation in the scoring function. The newly identified inhibitors are structurally diverse and have various chelating groups for the active-site ferrous ion including sulfonamide, carboxylate, N-benzo[1,2,5]oxadiazol-4-yl amide, and 2-[1,2,4]triazolo[3,4-b]][1,3,4]thiadiazol-3-yl-quinoline moieties.

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