Interleukin (IL)-13 is a key cytokine in asthma pathogenesis. We used constitutive and inducible overexpression transgenic mice to characterize the mechanisms by which IL-13 causes phenotypic alterations in the lung. These studies demonstrated that chemokine receptor-2, transforming growth factor-β1, and IL-11 play an important role in the regulation of inflammation and remodeling in the IL-13-treated lung. The study results also demonstrated that IL-13 induces vascular endothelial growth factor, which causes bronchial circulation neovascularization in the murine airway. Last, it was demonstrated that IL-13 induces adenosine accumulation and that adenosine in turn stimulates IL-13 elaboration. These approaches validated in vivo genetic targets against which therapies can be directed to selectively regulate aspects of the IL-13 phenotype.