Assaying the Action of Secreted Semaphorins on Vascular Permeability

Blood vessels compartmentalize blood flow and irrigate tissues, while allowing bidirectional exchanges. Vascular permeability permits fluids, small molecules and cells to cross the endothelial barrier. This process can be modulated, among others, by the guidance molecules from the semaphorin family. Here, we describe both in vitro and in vivo assays to evaluate the effects of Semaphorin 3A on vascular permeability. We also focused this chapter on methods to preclude semaphorin effects validating its pro-permeability action. These approaches could then be applied to other potential semaphorins and molecules modulating permeability.