Figure 7.

Sprouting capacity of HUVEC spheroids cocultured with HEK-293 cells secreting tenascin-W or tenascin-C in a type I collagen gel. A) HUVEC spheroids were combined in a type I collagen gel with HEK-293 spheroids in the presence of 10 ng/ml VEGF. HUVEC and HEK-293 spheroids were prepared with cells beforehand marked with DiO (green) and DiL (red) dyes, respectively. HEK-293 cells used in these experiments were stably transfected to express an empty plasmid (293), a teneurin-4 construct (Ten4), tenascin-W (TNW), or tenascin-C (TNC). Note that the sprouting capacity of HUVEC spheroids is increased only in the vicinity of 293 cells secreting TNW or TNC. Scale bar = 200 μm. B) HUVEC spheroids were added to type I collagen gels populated with dissociated HEK-293. After 48 h, pictures of 10 randomly chosen spheroids/condition were acquired. CSLs were quantified, measuring the total length of all sprouting processes originating from a single spheroid. Note that inclusion of HEK-293 cells secreting TNW and TNC significantly increased the sprouting capacity of HUVEC spheroids.