Publications by authors named "Hakmo Lee"

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs.

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Background: Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with an increased risk of other gynecological disorders, such as endometrial hyperplasia (EH). However, substantial factors in the comorbidity of EH and PCOS remain to be investigated. We analyzed trend changes in PCOS and factors related to the comorbidity of PCOS and EH using data from the Korea National Health Insurance (KNHI) claims database.

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Therapeutic applications of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have attracted considerable attention because of their immunomodulatory properties against immune-mediated, inflammatory diseases. Here, we demonstrated enhanced immunomodulatory properties of EVs secreted from endoplasmic reticulum (ER) stress inducer thapsigargin (TSG)-primed human Wharton's jelly-derived MSCs (WJ-MSCs). EVs from TSG-primed WJ-MSCs (TSG-EV) showed increased yield and expression of immunomodulatory factors, such as transforming growth factor-β1 (TGFβ), cyclooxygenase-2 (COX2), and especially indoleamine 2,3-dioxygenase (IDO), compared to control EVs.

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Background: Islet transplantation might be a logical strategy to restore insulin secretion for the treatment of diabetes, however, the scarcity of donors poses an obstacle for such a treatment. As an alternative islet source, differentiation of stem cells into insulin-producing cells (IPCs) has been tried. Many protocols have been developed to improve the efficiency of differentiation of stem cells into IPCs.

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Norcantharidin (NCTD), a demethylated analog of cantharidin isolated from blister beetles, has been used as a promising anticancer agent; however, the underlying function of NCTD against human oral squamous cell carcinoma (OSCC) has not been fully understood. Here, this study was aimed to investigate the apoptotic effect and molecular targets of NCTD in human OSCC in vitro and in vivo. The anticancer effects of NCTD and its related molecular mechanisms were evaluated by trypan blue exclusion assay, live/dead assay, western blotting, 4-6-Diamidino-2-Phenylindole (DAPI) staining, flow cytometric analysis, Terminal Deoxynucleotidyl Transferase dUTP Nick end Labeling (TUNEL) assay, and immunohistochemistry.

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Article Synopsis
  • Researchers are exploring stem cell-derived insulin producing cells (IPCs) as a potential alternative to traditional islet transplantation for treating diabetes.
  • Current methods to differentiate stem cells into IPCs are lengthy and complex, but this study shows that bone marrow nucleated cells (BMNCs) can be converted into IPCs more efficiently using conditioned media from stressed pancreatic β-cells.
  • This method produced IPCs that expressed key insulin-producing markers, improved diabetic conditions in mice, and suggests that differentiating factors are contained within micro particles rather than being released as soluble substances.
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Purpose: ABT-263 is a potent BH3 mimetic that possesses anticancer potential against various types of cancer. In general, this potential is due to its high binding affinity to anti-apoptotic proteins in the Bcl-2 family that disrupt sequestration of pro-apoptotic proteins. In the present study, we sought to identify an alternative regulatory mechanism responsible for ABT-263-mediated anticancer activity in human oral cancer.

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Rodent stem cells demonstrated regenerative effects in diabetic neuropathy via improvement in nerve perfusion. As a pre-clinical step, we explored if human mobilized mononuclear cells (hMNC) would have the same effects in rats. hMNC were injected into Rt.

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PERK is a pancreatic endoplasmic reticulum (ER) kinase. Its complete deletion in pancreatic β cells induces insulin deficiency; however, the effects of partial suppression are unclear. We investigated the effect of partial PERK suppression using the specific PERK inhibitors GSK2606414 and GSK2656157.

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Post-translational modification by bonding of small ubiquitin-like modifier (SUMO) peptides influences various cellular functions, and is regulated by SUMO-specific proteases (SENPs). Several proteins have been suggested to have diverse impact on insulin synthesis and secretion through SUMO modification in β cells. However, the role of SUMO modification in β cell mass has not been established.

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Incretin-based therapy such as GLP-1 receptor agonists and DPP-4 inhibitors for type 2 diabetes mellitus is characterized by glucose-dependent insulin secretion and glucose-inhibited glucagon secretion. Recently, autophagy deficiency in islet β cells has been shown to contribute to the pathogenesis of type 2 diabetes mellitus however, with the role of incretin has not been established. To evaluate the role of autophagy in incretin effects, 8-week-old male β cell-specific Atg7 knockout (Atg7(Δβ cell)) mice and wild-type mice were administered vildagliptin for 12 weeks.

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To understand the cellular mechanism underlying the therapeutic effects exerted by hematopoietic stem cell transplantation in the repair of tissue damage, we investigated the in vivo dynamics of bone marrow (BM) lineage-negative (Lin(-)) cells transplanted into mice with hyper sensitivity dermatitis. Longitudinal in vivo imaging and flow cytometry analyses revealed that Lin(-) cells home directly to inflamed skin within 6 h, where they undergo extensive expansion with the peak on day 14 post-transplantation, and preferential differentiation into CD11b(+)Ly6G(int)Ly6C(+) cells by day 7. Cells with phenotypic profiles of neutrophils, macrophages, and DCs appeared in inflamed skin on day 14.

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Abnormally high levels of circulating free fatty acids can lead to pancreatic islet β-cell dysfunction and apoptosis, contributing to β-cell failure in Type 2 diabetes. The NAD+-dependent protein deacetylase Sirtuin-3 (SIRT3) has been implicated in Type 2 diabetes. In this study, we tested whether SIRT3 overexpression affects palmitate-induced β-cell dysfunction in cells of line NIT1, which are derived from mouse pancreatic β-cells.

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Motivation: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging.

Results: We present an improved version of EVpedia, a public database for EVs research.

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Background: Damaged mitochondria are removed by autophagy. Therefore, impairment of autophagy induces the accumulation of damaged mitochondria and mitochondrial dysfunction in most mammalian cells. Here, we investigated mitochondrial function and the expression of mitochondrial complexes in autophagy-related 7 (Atg7)-deficient β-cells.

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Various investigators have attempted to overcome the shortage of available hematopoietic stem/progenitor cells (HSPCs) by facilitating their engraftment after transplantation. Preconditioning of HSPCs with the granulocyte-derived cationic peptide LL-37 has been suggested as a useful strategy to facilitate engraftment of transplanted cells by enhancing their responsiveness to CXCL12. In this study, we evaluated whether LL-37 preconditioning is acceptable for clinical application.

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Graft-versus-host disease (GVHD) is a fatal complication that occurs after allogeneic hematopoietic stem cell transplantation. To understand the dynamics of CD4 and CD8 T cell production of IFN-γ and IL-17 during GVHD progression, we established a GVHD model by transplanting T cell-depleted bone marrow (TCD-BM) and purified T cells from B6 mice into irradiated BALB.B, creating an MHC-matched but minor histocompatibility (H) antigen-mismatched transplantation (B6 → BALB.

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Bone marrow (BM) has been considered as a reservoir of stem/progenitor cells which are able to differentiate into ectodermal, endodermal, and mesodermal origins in vitro as well as in vivo. Following adequate stimulation, such as granulocyte stimulating factor (G-CSF) or AMD3100, BM resident stem/progenitor cells (BMSPCs) can be mobilized to peripheral blood. Several host-related factors are known to participate in this mobilization process.

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Mithramycin A (Mith) is an aureolic acid-type polyketide produced by various soil bacteria of the genus Streptomyces. Mith inhibits myeloid cell leukemia-1 (Mcl-1) to induce apoptosis in prostate cancer, but the molecular mechanism underlying this process has not been fully elucidated. The aim of this study was therefore to investigate the detailed molecular mechanism related to Mith-induced apoptosis in prostate cancer cells.

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The successful islet transplantation, for the treatment of type 1 diabetes, depends on the quantity and the quality of transplanted islets. Previously, it has reported that the significant loss of isolated islet mass could be prevented by sphingolipid metabolite, sphinogosine 1-phophate (S1P). This study was performed to elucidate whether the beneficial effects of S1P maintaining isolated pancreatic islets ex vivo are mimicked by modulation of intracellular S1P.

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Early graft loss in islet transplantation means that a large amount of donor islets is required. Endothelial cells and endothelial colony-forming cells (ECFCs) have been reported to improve instant blood-mediated inflammatory reaction (IBMIR) in vitro. In this study, we examined if ECFC-coated porcine islets would prevent early graft loss in vivo.

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Current strategies to accelerate hematopoietic reconstitution after transplantation include transplantation of greater numbers of hematopoietic stem/progenitor cells (HSPCs) or ex vivo expansion of harvested HSPCs before transplant. However, the number of cells available for transplantation is usually low, and strategies to expand HSPCs and maintain equivalent engraftment capability ex vivo are limited. We noted that activated granulocyte-derived cationic peptides positively primed responsiveness of HSPCs to a CXCL12 gradient.

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Background And Objectives: Hyperacute rejection (HAR) is a major obstacle to successful xenotransplantation of vascularized organs. This study was conducted to observe the effect of hemolysis of perfused human whole blood on pig heart function, and determine the major risk factors for preservation of xenoperfused cardiac function using ex-vivo pig to human xenogeneic cardiac perfusion model.

Materials And Methods: Harvested pig hearts were perfused with normal human whole blood (group 1), two different types of pre-treated human whole blood (group 2: immunoglobulins were depleted by plasmapheresis, group 3: pre-treated with plasmapheresis, GAS914, cobra venom factor (CVF) and steroid), and normal porcine whole blood as control (group 4) for 3 hours.

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Objective: Having previously demonstrated that the complement system modulates mobilization of hematopoietic stem/progenitor cells (HSPC) in mice, we investigated the involvement of C5 cleavage fragments (C5a/(desArg)C5a) in human HSPC mobilization.

Materials And Methods: C5 cleavage fragments in the plasma were evaluated by enzyme-linked immunosorbent assay using human anti-(desArg)C5a antibody, and expression of the C5a/(desArg)C5a receptor (CD88) in hematopoietic cells by flow cytometry. We also examined the chemotactic responses of hematopoietic cells to C5 cleavage fragments and expression of stromal cell-derived factor-1 (SDF-1)-degrading proteases that perturb retention of HSPC in bone marrow, namely matrix metalloproteinase (MMP)-9, membrane type (MT) 1-MMP, and carboxypeptidase M.

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The mobilization of hematopoietic stem/progenitor cells (HSPCs) from bone marrow into peripheral blood (PB) is still not fully understood. Different chemokines, cytokines, growth factors, and neurotransmitters have been described that facilitate this process. However, mounting evidence suggests that mobilization of HSPCs is a part of the immune response and is mediated by innate immunity.

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