Dil-Conjugated Acetylated Low-Density Lipoprotein (Dil-ace-LDL) Uptake and Tube Formation

Dil-ace-LDL uptake and tube formation were evaluated as described previously (Zhang et al., 2014; Su et al., 2018). For DiI-ace-LDL uptake assay, hiPSC-ECs were incubated with DAPI overnight (1:1,000 dilution) and then in EGM supplemented with 10 μg/mL of DiI-ace-LDL (Life Technologies, United States) at 37 °C for 12 h. For tube-formation assay, cells were seeded in 48-well plate that had been coated with Matrigel (Corning, United States) and incubated at 37°C for 24 h. Numbers of node, junction, and branches and total branches length per magnification (10×) were quantified using angiogenesis analyzer of Image J.