Engineering Professor Makes Cell Behavior Discovery

Pictured are endothelial cells forming precursors of blood vessel networks. Individual endothelial cells were fluorescently tagged and tracked during tissue formation (left). According to their behavior, three clusters of cells could be identified (shown on the right as purple, light blue and dark blue, and unclustered cells colored in gray). The behavioral patterns of most cells were not reflected in the bulk average behavior, and some of these patterns correlated to their final structural role within the microvascular plexus. Biologists tend to look at cells in bulk, observing them as a group and taking the average behavior as the norm — the assumption is that genetically identical cells all behave the same way. In a paper to be published in the online Early Edition of Proceedings of the National Academy of Sciences this week, Sam Sia , assistant professor of biomedical engineering at Columbia Engineering, presents the results of his four-year tissue-engineering study that show a surprising range of variation in how individual cells behave during formation of a blood vessel. Sia and his team used a new method to painstakingly observe and track individual behaviors, characterizing, for the first time, what happens when human endothelial cells move from an initial dispersed state to the formation of capillary-like structures.