KDR and pulmonary emphysema: It has been shown that inhibition of vascular endothelial growth factor (VEGF) signaling by genetic disruption of Vegf (Tang et al., 2004), pharmacological blockade of VEGFR signaling (Kasahara et al., 2000), or small interfering RNA (siRNA)-mediated knockdown of Vegfr2 in ECs (Dahlman et al., 2014) induces emphysema, a disease characterized by decreased pulmonary surface area.