Increased expression of angiopoietins and Tie2 in the lungs of chronic asthmatic mice.

Angiopoietin (Ang)1 and Ang2 are ligands for Tie2 tyrosine kinase receptor (Tie2). Elevated levels of Ang1 and Ang2 in induced sputum of patients with asthma have been reported, with a positive correlation of Ang2 levels with the severity of airway occlusion. Although studies have shown Tie2-mediated regulation of nonvascular cells in some pathological conditions, current knowledge on Tie2 signaling in asthma is limited to the vasculature. We examined the expression pattern of Ang1, Ang2, vascular endothelial growth factor (VEGF), and Tie2 and their correlation with the degree of airway remodeling in the lung of ovalbumin (OVA)-sensitized and OVA-challenged mice with airway hyperresponsiveness. Lung tissues were isolated from Balb/c mice after OVA sensitization and challenge. Hematoxylin and eosin, periodic acid-Schiff, and trichrome staining were used to show the lung pathology. The expression of Ang1, Ang2, VEGF, and Tie2 was examined using immunofluorescence, Western blot, ELISA, and real-time PCR. In ...