Airway
inflammation and remodeling are important pathophysiologic features of chronic
asthma. Previously, we have developed a mouse model of prolonged
allergen challenge which exhibits many characteristics of chronic
asthma such as goblet cell
hyperplasia and subepithelial
collagen deposition, in association with an increase in lung expression of the profibrotic mediator,
TGF-beta. The aim of this study was to determine the effects of blockade of
TGF-beta on the development of airway
inflammation and remodeling using our murine model of prolonged
allergen challenge. Importantly anti-
TGF-beta Ab was administered therapeutically, with dosing starting after the onset of established eosinophilic airway
inflammation. Therapeutic treatment of mice with anti-
TGF-beta Ab significantly reduced peribronchiolar extracellular matrix deposition, airway smooth muscle cell proliferation, and mucus production in the lung without affecting established airway
inflammation and Th2
cytokine production. Thus, our data suggest that it might be possible to uncouple airway
inflammation and remodeling during prolonged
allergen challenge. In addition, anti-
TGF-beta Ab treatment was shown to regulate active
TGF-beta signaling in situ with a reduction in the expression of phospho-Smad 2 and the concomitant up-regulation of Smad 7 in lung sections. Therefore, this is the first report to suggest that anti-
TGF-beta Ab treatment prevents the progression of
airway remodeling following
allergen challenge even when given in a therapeutic mode. Moreover, the molecular mechanism behind this effect may involve regulation of active
TGF-beta signaling.