Matrix deformations around angiogenic sprouts correlate to sprout dynamics and suggest pulling activity

AbstractAngiogenesis is the formation of new blood vessels from the pre-existing vasculature. It is essential for normal tissue growth and regeneration, and also plays a key role in many diseases [Carmeliet in Nat Med 9:653 –660, 2003]. Cytoskeletal components have been shown to be important for angiogenic sprout initiation and maintenance [Kniazeva and Putnam in Am J Physiol 297:C179–C187, 2009] as well as endothelial cell shape control during invasion [Elliott et al. in Nat Cell Biol 17:137–147, 2015]. The exac t nature of cytoskeleton-mediated forces for sprout initiation and progression, however, remains poorly understood. Questions on the importance of tip cell pulling versus stalk cell pushing are to a large extent unanswered, which among others has to do with the difficulty of quantifying and resolvin g those forces in time and space. We developed methods based on time-lapse confocal microscopy and image processing—further termed 4D displacement microscopy—to acquire detailed, spatially and temporally resolved extracellular matrix (ECM) deformations, indicative of cell-ECM mechanical interact ions around invading sprouts. We demonstrate that matrix deformations dependent on actin-mediated force generation are spatio-temporally correlated with sprout morphological dynamics. Furthermore, sprout tips were found to exert radially pulling forces on the extracellular matrix, which were quantif ied by means of a computational model of collagen ECM mechanics. Protrus...
Source: Angiogenesis - Category: Molecular Biology Source Type: research