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Browsing by Author "Gil, Chang-Hyun"
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Item Biomarkers of Oxidative Stress and Endogenous Antioxidants for Patients with Chronic Subjective Dizziness(Nature Research, 2020-01-30) Fang, Zhigang; Huang, Keer; Gil, Chang-Hyun; Jeong, Jin-Woo; Yoo, Ho-Ryong; Kim, Hyeong-Geug; Biochemistry and Molecular Biology, School of MedicineAs a neurotologic disorder of persistent non-vertiginous dizziness, chronic subjective dizziness (CSD) arises unsteadily by psychological and physiological imbalance. The CSD is hypersensitivity reaction due to exposure to complex motions visual stimuli. However, the pathophysiological features and mechanism of the CSD still remains unclearly. The present study was purposed to establish possible endogenous contributors of the CSD using serum samples from patients with the CSD. A total 199 participants were gathered and divided into two groups; healthy (n = 152, male for 61, and female for 91) and CSD (n = 47, male for 5, female for 42), respectively. Oxidative stress parameters such as, hydrogen peroxide and reactive substances were significantly elevated (p < 0.01 or p < 0.001), whereas endogenous antioxidant components including total glutathione contents, and activities of catalase and superoxide dismutase were significantly deteriorated in the CSD group (p < 0.01 or p < 0.001) as comparing to the healthy group, respectively. Serum levels of tumor necrosis factor -α and interferon-γ were significantly increased in the CSD participants (p < 0.001). Additionally, emotional stress related hormones including cortisol, adrenaline, and serotonin were abnormally observed in the serum levels of the CSD group (p < 0.01 or p < 0.001). Our results confirmed that oxidative stress and antioxidants are a critical contributor of pathophysiology of the CSD, and that is first explored to establish features of redox system in the CSD subjects compared to a healthy population.Item Differentiation, Evaluation, and Application of Human Induced Pluripotent Stem Cell–Derived Endothelial Cells(AHA, 2017-11) Lin, Yang; Gil, Chang-Hyun; Yoder, Mervin C.; Pediatrics, School of MedicineThe emergence of induced pluripotent stem cell (iPSC) technology paves the way to generate large numbers of patient-specific endothelial cells (ECs) that can be potentially delivered for regenerative medicine in patients with cardiovascular disease. In the last decade, numerous protocols that differentiate EC from iPSC have been developed by many groups. In this review, we will discuss several common strategies that have been optimized for human iPSC-EC differentiation and subsequent studies that have evaluated the potential of human iPSC-EC as a cell therapy or as a tool in disease modeling. In addition, we will emphasize the importance of using in vivo vessel-forming ability and in vitro clonogenic colony–forming potential as a gold standard with which to evaluate the quality of human iPSC-EC derived from various protocols.Item iPSC-Derived Vascular Cell Spheroids as Building Blocks for Scaffold-Free Biofabrication(Wiley, 2017) Moldovan, Leni; Barnard, April; Gil, Chang-Hyun; Lin, Y.; Grant, Maria B.; Yoder, Mervin C.; Prasain, Nutan; Moldovan, Nicanor I.; Biomedical Engineering, School of Engineering and TechnologyRecently a protocol is established to obtain large quantities of human induced pluripotent stem cells (iPSC)-derived endothelial progenitors, called endothelial colony forming cells (ECFC), and of candidate smooth-muscle forming cells (SMFC). Here, the suitability for assembling in spheroids, and in larger 3D cell constructs is tested. iPSC-derived ECFC and SMFC are labeled with tdTomato and eGFP, respectively. Spheroids are formed in ultra-low adhesive wells, and their dynamic proprieties are studied by time-lapse microscopy, or by confocal microscopy. Spheroids are also tested for fusion ability either in the wells, or assembled on the Regenova 3D bioprinter which laces them in stainless steel micro-needles (the “Kenzan” method). It is found that both ECFC and SMFC formed spheroids in about 24 h. Fluorescence monitoring indicated a continuous compaction of ECFC spheroids, but stabilization in those prepared from SMFC. In mixed spheroids, the cell distribution changed continuously, with ECFC relocating to the core, and showing pre-vascular organization. All spheroids have the ability of in-well fusion, but only those containing SMFC are robust enough to sustain assembling in tubular structures. In these constructs a layered distribution of alpha smooth muscle actin-positive cells and extracellular matrix deposition is found. In conclusion, iPSC-derived vascular cell spheroids represent a promising new cellular material for scaffold-free biofabrication.Item Origin, prospective identification, and function of circulating endothelial colony-forming cells in mice and humans(The American Society for Clinical Investigation, 2023-03-08) Lin, Yang; Banno, Kimihiko; Gil, Chang-Hyun; Myslinski, Jered; Hato, Takashi; Shelley, William C.; Gao, Hongyu; Xuei, Xiaoling; Basile, David P.; Yoshimoto, Momoko; Prasain, Nutan; Tarnawsky, Stefan P.; Adams, Ralf H.; Naruse, Katsuhiko; Yoshida, Junko; Murphy, Michael P.; Horie, Kyoji; Yoder, Mervin C.; Pediatrics, School of MedicineMost circulating endothelial cells are apoptotic, but rare circulating endothelial colony-forming cells (C-ECFCs), also known as blood outgrowth endothelial cells, with proliferative and vasculogenic activity can be cultured; however, the origin and naive function of these C-ECFCs remains obscure. Herein, detailed lineage tracing revealed murine C-ECFCs emerged in the early postnatal period, displayed high vasculogenic potential with enriched frequency of clonal proliferative cells compared with tissue-resident ECFCs, and were not committed to or derived from the BM hematopoietic system but from tissue-resident ECFCs. In humans, C-ECFCs were present in the CD34bright cord blood mononuclear subset, possessed proliferative potential and in vivo vasculogenic function in a naive or cultured state, and displayed a single cell transcriptome sharing some umbilical venous endothelial cell features, such as a higher protein C receptor and extracellular matrix gene expression. This study provides an advance for the field by identifying the origin, naive function, and antigens to prospectively isolate C-ECFCs for translational studies.Item Physioxia enhances T-cell development ex vivo from human hematopoietic stem and progenitor cells(Nova Science, 2020-11) Shin, Dong-Yeop; Huang, Xinxin; Gil, Chang-Hyun; Aljoufi, Arafat; Ropa, James; Broxmeyer, Hal E.; Microbiology and Immunology, School of MedicineUnderstanding physiologic T-cell development from hematopoietic stem (HSCs) and progenitor cells (HPCs) is essential for development of improved hematopoietic cell transplantation (HCT) and emerging T-cell therapies. Factors in the thymic niche, including Notch 1 receptor ligand, guide HSCs and HPCs through T-cell development in vitro. We report that physiologically relevant oxygen concentration (5% O2,physioxia), an important environmental thymic factor, promotes differentiation of cord blood CD34+ cells into progenitor T (proT) cells in serum-free and feeder-free culture system. This effect is enhanced by a potent reducing and antioxidant agent, ascorbic acid. Human CD34+ cell-derived proT cells in suspension cultures maturate into CD3+ T cells in an artificial thymic organoid (ATO) culture system more efficiently when maintained under physioxia, compared to ambient air. Low oxygen tension acts as a positive regulator of HSC commitment and HPC differentiation toward proT cells in the feeder-free culture system and for further maturation into T cells in the ATO. Culturing HSCs/HPCs in physioxia is an enhanced method of effective progenitor T and mature T-cell production ex vivo and may be of future use for HCT and T-cell immunotherapies.Item Specific mesoderm subset derived from human pluripotent stem cells ameliorates microvascular pathology in type 2 diabetic mice(American Association for the Advancement of Science, 2022) Gil, Chang-Hyun; Chakraborty, Dibyendu; Vieira, Cristiano P.; Prasain, Nutan; Calzi, Sergio Li; Fortmann, Seth D.; Hu, Ping; Banno, Kimihiko; Jamal, Mohamed; Huang, Chao; Sielski, Micheli S.; Lin, Yang; Huang, Xinxin; Dupont, Mariana D.; Floyd, Jason L.; Prasad, Ram; Longhini, Ana Leda F.; McGill, Trevor J.; Chung, Hyung-Min; Murphy, Michael P.; Kotton, Darrell N.; Boulton, Michael E.; Yoder, Mervin C.; Grant, Maria B.; Pediatrics, School of MedicineHuman induced pluripotent stem cells (hiPSCs) were differentiated into a specific mesoderm subset characterized by KDR+CD56+APLNR+ (KNA+) expression. KNA+ cells had high clonal proliferative potential and specification into endothelial colony-forming cell (ECFCs) phenotype. KNA+ cells differentiated into perfused blood vessels when implanted subcutaneously into the flank of nonobese diabetic/severe combined immunodeficient mice and when injected into the vitreous of type 2 diabetic mice (db/db mice). Transcriptomic analysis showed that differentiation of hiPSCs derived from diabetics into KNA+ cells was sufficient to change baseline differences in gene expression caused by the diabetic status and reprogram diabetic cells to a pattern similar to KNA+ cells derived from nondiabetic hiPSCs. Proteomic array studies performed on retinas of db/db mice injected with either control or diabetic donor-derived KNA+ cells showed correction of aberrant signaling in db/db retinas toward normal healthy retina. These data provide "proof of principle" that KNA+ cells restore perfusion and correct vascular dysfunction in db/db mice.