Semaphorin 3E Inhibits House Dust Mite-Induced Angiogenesis in a Mouse Model of Allergic Asthma

Increased angiogenesis is a characteristic feature of remodeling in asthmatic airways and stems from the imbalance between pro-angiogenic and anti-angiogenic factors. Surprisingly, the factors regulating this process in allergic asthma are poorly defined. Previously, we showed an important role of semaphorins 3E (Sema3E) in growth factor induced airway smooth muscle proliferation and migration in vitro, and in down-regulating airway inflammation, T helper 2/T helper 17 cytokine response, mucus cell hyperplasia, and airway hyperresponsiveness in vivo. However, the role of Sema3E in airway angiogenesis is not fully understood. Here, we investigated the role of Sema3E in airway angiogenesis using a house dust mite (HDM) murine model of allergic asthma. Intranasal treatment with recombinant Sema3E significantly reduced the expression of angiogenesis markers within the airways of HDM-challenged mice compared with untreated mice. HDM-induced expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 protein were diminished substantially on Sema3E treatment. Interestingly, Sema3E-treated mice showed an enhanced expression of the negative regulator of angiogenesis, soluble VEGF receptor 1, compared with the untreated mice. These events were reversed in Sema3E-deficient mice at baseline or on HDM challenge. Taken together, this study provides the first evidence that Sema3E modulates angiogenesis in allergic asthmatic airways via modulating pro- and anti-angiogenic factors.