CD151 reinforces vascular stability and regulates vascular permeability. (A) Loss of CD151 expression disrupted EC capillary-like structures on Matrigel. HMEC-MOCK and -CD151 KD (top) or MLEC-WT and -CD151 KO (bottom) cells were plated on Matrigel and photographed with an Olympus CK2 inverted microscope under a 4×/0.10 NA objective equipped with a microscope digital camera (DCM500) at the indicated time points. The cable-enclosed regions were counted and compared. Bar represents 250 μm. *P < .01. (B) CD151 ablation results in increased vascular permeability in mice. Evans blue dye (30 mg/kg in PBS) was injected intravenously through the retro-orbital sinus into 12-week-old male mice. Mustard oil in mineral oil (5% volume/volume) or mineral oil alone was applied to the dorsal and ventral surfaces of the ears twice, at 0 minutes and 15 minutes later. After 30 minutes of circulation, the dye leakage area at the ventral surface of the ear was imaged with a Nikon SMZ1500 dissecting microscope equipped with a Nikon DXM1200 digital camera and the content of dye in ears was determined after the extraction with formamide overnight at 55°C. Shown are representative images (top) and quantitative results from WT and CD151 KO mice from the Miles assay. n = 15. Bar represents 1 mm. **P < .05.