Generation of HA-iPSCs and HA-iECs from HA patients. (A) Schematic overview of epithelial cell isolation from patient urine (HA-UECs), reprogramming to HA-iPSCs through the episomal expression of reprogramming factors (OCT4, SOX2, KLF4, L-MYC, and LIN-28), and differentiation to HA-iECs using modified RNA encoding ETV2. (B) Phase-contrast imaging of the initial appearance (left) and expansion (right) of cells during the reprogramming of HA-UECs (top) to HA-iPSCs (middle), and subsequent differentiation into HA-iECs (bottom). (C) Immunofluorescence staining of HA-iPSCs for stem cell markers OCT4, SOX2, and NANOG, and endothelial cell marker CD31. Cell nuclei stained by 4′,6-diamidino-2-phenylindole (DAPI). (D) Flow cytometry analysis of HA-iPSCs for stem cell surface marker SSEA4 . Solid gray isotype-matched control is overlaid on the histogram. (E) Differentiation efficiency of HA-iPSCs into CD31⁺/VE-Cadherin⁺ HA-iECs (top right box) quantified by flow cytometry and compared with the efficiency in nonhemophilic human iPSC clones (Control-iPSCs). Bars represent mean ± standard deviation (SD). (F) Flow cytometry analysis of HA-iECs for endothelial cell surface markers CD31 and VE-Cadherin, and stem cell surface markers SSEA4 and Tra-1-81. Solid gray isotype-matched controls are overlaid on each histogram. (G) Immunofluorescent staining of HA-iECs for endothelial cell markers CD31, VE-Cadherin, and VWF, and stem cell marker OCT4. Cell nuclei stained by DAPI. Scale bars, 100 μm (G), 200 μm (C), and 500 μm (B). n.s., no statistical differences.