BACKGROUND: Stem cell engineering is appealing consideration for regenerating damaged endothelial cells (ECs) because stem cells can differentiate into EC-like cells. In this study, we demonstrate that tonsil-derived mesenchymal stem cells (TMSCs) can differentiate into EC-like cells under optimal physiochemical microenvironments.METHODS: TMSCs were preconditioned with Dulbecco's Modified Eagle Medium (DMEM) or EC growth medium (EGM) for 4 days and then replating them on Matrigel to observe the formation of a capillary-like network under light microscope. Microarray, quantitative real time polymerase chain reaction, Western blotting and immunofluorescence analyses were used to evaluate the expression of gene and protein of EC-related markers.RESULTS: Preconditioning TMSCs in EGM for 4 days and then replating them on Matrigel induced the formation of a capillary-like network in 3 h, but TMSCs preconditioned with DMEM did not form such a network. Genome analyses confirmed that EGM preconditioning significantly affected the expression of genes related to angiogenesis, blood vessel morphogenesis and development, and vascular development. Western blot analyses revealed that EGM preconditioning with gelatin coating induced the expression of endothelial nitric oxide synthase (eNOS), a mature EC-specific marker, as well as phosphorylated Akt at serine 473, a signaling molecule related to eNOS activation. Gelatin-coating during EGM preconditioning further enhanced the stability of the capillary-like network, and also resulted in the network more closely resembled to those observed in human umbilical vein endothelial cells.CONCLUSION: This study suggests that under specific conditions, i.e., EGM preconditioning with gelatin coating for 4 days followed by Matrigel, TMSCs could be a source of generating endothelial cells for treating vascular dysfunction.
Blood Vessels ; Blotting, Western ; Eagles ; Endothelial Cells ; Fluorescent Antibody Technique ; Gelatin ; Genome ; Human Umbilical Vein Endothelial Cells ; Mesenchymal Stromal Cells ; Morphogenesis ; Nitric Oxide Synthase Type III ; Palatine Tonsil ; Real-Time Polymerase Chain Reaction ; Serine ; Stem Cells

Differentiation of mesenchymal stem cells (MSC) into a variety of cell lineages such as adipocytes, osteocytes, and chondrocytes is often accompanied up-regulation of autophagy. In our study, we demonstrated that the expression of autophagy-associated proteins (p-Beclin 1, LC3A, LC3B, p-AMPK, p-mTOR and ATG3, ATG7, and ATG12-5) over a period of time was hardly distinguishable from control tonsil-derived MSC (TMSC). Despite the unnoticeable difference in autophagy activation between differentiated TMSC (dTMSC) and the control (cTMSC), we reported significant changes in intracellular compositions in differentiated TMSC into functional parathyroid-like cells secreting parathyroid hormone (PTH). By using transmission electron microscopy (TEM), we observed accumulation of multivesicular bodies (MVB) comprising small, degraded compartments densely accumulated as dark granular or amorphous clumps, multilamellar bodies and lipid droplets in dTMSC. However, no such structures were found in cTMSC. These results suggest that differentiation of TMSC into parathyroid-like cells producing PTH hormone is hardly dependent on autophagy activation in the beginning of our conditions. Furthermore, our results of intracellular remodeling and accumulated endo-lysosomal storage bodies in the later stages of TMSC differentiation present a possible role of the structures in PTH secretion.
Adipocytes ; Autophagy ; Cell Lineage ; Chondrocytes ; Lipid Droplets ; Lysosomes* ; Mesenchymal Stromal Cells* ; Microscopy, Electron, Transmission ; Multivesicular Bodies ; Osteocytes ; Parathyroid Hormone ; Up-Regulation

Immune thrombocytopenia (ITP) is an autoimmune condition characterized by platelet destruction through antibody-mediated mechanism. ITP is one of the manifestations of a coronavirus disease, as well as an adverse event occurring after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several cases of ITP have been described after vaccination with two mRNA-based vaccines—BTN162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)—against SARS-CoV-2. Herein, we report a case of ITP occurring after vaccination with ChAdOx1 adenovirus vector nCoV-19 (AstraZeneca) vaccine in Korea. A 66-year-old woman presented with multiple ecchymoses on both upper and lower extremities and gingival bleeding, appearing 3 days after receiving the first dose of ChAdOx1 nCoV-19. Her laboratory results showed isolated severe thrombocytopenia without evidence of combined coagulopathy. She was diagnosed with ITP and successfully treated with high-dose dexamethasone and intravenous immunoglobulin. Clinical suspicion to identify vaccinerelated ITP is important to promptly initiate appropriate treatment.