The honor comes with a cash prize of 5,000 Euros and a travel award to encourage the graduates to expand their horizons with a postdoctoral stint abroad. The researchers will receive 2,000 Euros per month for half a year to visit another institute; if they have left the Association, they can use the award to visit any of the Helmholtz Institutes to pursue a topic that interests them.
Véronique’s thesis introduced a new model for the way cells build blood vessels during the formation of the circulatory system, in a process called angiogenesis. To provide nutrients for growing tissues, the endothelial cells that make blood vessels begin to sprout and push their way outward. Different sprouts have to connect in arc-like structures, and in the process they form the passage through which blood will flow.
Véronique began her work while Holger’s group was still located at the Cancer Research UK London Research Institute (now the Francis Crick Institute). At the time the predominant hypothesis held that small compartments called vacuoles in the endothelial cells fused together to form larger compartments, eventually opening to the membrane to create a channel between the cells.
“When we tried to observe such fusion events in the cells, we couldn’t see them. We started wondering whether the previous studies could have missed something, because of the low resolution of the imaging,” she says. “So I turned to a different type of microscope, a spinning disc confocal system that could image whole fields at a much higher spatial and temporal resolution.”
The work revealed a new mechanism to explain lumen formation: pressure from the bloodstream pushed at the surfaces of endothelial cells at the edge of the vessel, like a finger pushing into a balloon. Most of these deformations, termed “inverse blebs,” would eventually be eliminated by contractions of the cytoskeleton, a system of fibers under the cell surface. But some would remain, carving out a passage for the lumen. The dissertation worked out some of the molecular mechanisms responsible for the behavior of the cytoskeleton.
The hardest part about writing the dissertation, Véronique says, is the vast amount of background reading that was necessary. Angiogenesis has been the subject of a huge number of studies due to the roles of this process in development and disease. In both embryogenesis and cancer, blood vessels form at an accelerated rate to supply rapidly growing tissue.
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