Vascular Phenotype is Compromised in Dynamically Stiffening Hydrogel

Cardiovascular diseases are one of the leading causes of death worldwide with age mediated endothelial dysfunction as one of the major risk factors. Endothelial dysfunction is caused by a variety of reasons, such as oxidative stress, DNA damage and senescence. Although, observations in vivo showed a clear correlation between increased extracellular matrix (ECM) stiffness and morphological changes within the vasculature, the identification of underlying signaling pathways in endothelial cells remains challenging, due to the lack of physiological 3D systems. Here we report the use of a fibrillary hydrogel, composed of hyaluronic acid and collagen I, which is capable of dynamically changing its stiffness along cell culture. This hydrogel allows for the increase in stiffness after the development of a mature vascular network, therefore mimicking the natural process of aging ex vivo. Using this system we found that an increase in ECM stiffness leads to a decrease in vessel length, increase in lumen size and the disassembly of adherence junctions. We further observed that an increase in matrix stiffness leads to changes in cell contractility and pFAK signaling, leading to further increase in matrix stiffness and the disassembly of adherence junctions. Inhibition of cell contractility using blebbistatin partially rescues the vascular morphology and the integrity of adherence junctions. Support or Funding Information Maryland Stem Cell Fund (RS is MSCRF Fellow)