Isolation and Characterization of Primary Mouse Lung Endothelial Cells

The primary mouse lung endothelial cells (MLEC) were isolated from a 10-week-old, female, Balb/c mice and were cultured as described elsewhere^{29 (link)}. Briefly, freshly isolated mouse lung was minced using autoclaved scissors, digested by collagenase I, and filtered through a 70-μm cell strainer. The cell suspension was incubated with anti-rat Dynabeads (Thermo Fisher Scientific, MA, USA, 11035) conjugated with anti-mouse CD31 antibody (BD Biosciences, NJ, USA, 557355). Pooled cells were seeded in a 12-well-plate pre-coated with 0.1% gelatin. Upon reaching confluence, the cells were trypsinized and then incubated with anti-mouse ICAM-2 antibody (BD Biosciences, NJ, USA, 553326) conjugated Dynabeads. Pooled cells were seeded in 12-well-plates pre-coated with 0.1% gelatin. Harvested cells were assessed using tube formation assay, 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl-indocarbocyanine perchlorate Low Density Lipoprotein (DiI-Ac-LDL) uptake, and CD31 gene expression (Fig. S4).