Anti-apoptotic effect of the Shh signaling pathway in cigarette smoke extract induced MLE 12 apoptosis

INTRODUCTION: Many studies have shown that COPD is associated with apoptosis of bronchial or alveolar epithelial cells. Alveolar type II epithelial cells (AECII) play an important role in the pathogenetic process. Cigarette smoke extract (CSE) can induce apoptosis of AECII. The Sonic hedgehog (Shh) pathway is involved in many adult lung diseases. We aimed to verify the anti-apoptotic effect of Shh in the AECII apoptosis induced by CSE. METHODS: Mouse lung epithelial type II cells, MLE 12, were treated by 5% CSE for 24 hours. Apoptosis was measured using flow cytometry and expression of the anti-apoptotic factor BCL-2. The role of the hedgehog pathway in cell apoptosis was assessed by real-time RT-PCT and western blotting to measure the expression of Sonic hedgehog, Patched 1, and Gli1. Recombinant mouse Sonic hedgehog was used to overexpress the Shh pathway. RESULTS: CSE could induce MLE 12 apoptosis. Sonic hedgehog, Patched 1 and the Gli1 were decreased in the CSE induced MLE 12 apoptosis. Overexpression Shh could partially reverse the CSE induced apoptosis. CONCLUSIONS: Activation of the Shh pathway may relieve the CSE induced MLE 12 apoptosis.