Embryonic Overexpression of Receptors for Advanced Glycation End-Products by Alveolar Epithelium Induces an Imbalance between Proliferation and Apoptosis

作者：Stogsdill Jeffrey A; Stogsdill Megan P; Porter Jason L; Hancock Joshua M; Robinson Adam B; Reynolds Paul R^*

来源：American Journal of Respiratory Cell and Molecular Biology, 2012, 47(1): 60-66.

DOI：10.1165/rcmb.2011-0385OC

• RAGE
• apoptosis
• lung
• transgenic

Receptors for advanced glycation end-products (RAGEs) are multi-ligand cell surface receptors highly expressed in the lung that contribute to alveolar epithelial cell differentiation during embryogenesis and the modulation of pulmonary inflammation during disease. When RAGEs are overexpressed throughout embryogenesis, severe lung hypoplasia ensues, culminating in perinatal lethality. However, the possible mechanisms that lead to the disappearance of pulmonary tissue remain unclear. A time course of lung organogenesis, commencing on Embryonic Day (E) 12.5, demonstrated that increased RAGE expression primarily alters lung morphogenesis beginning on E16.5. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) immuno-histochemistry and immunoblotting for active caspase-3 confirmed a shift toward apoptosis in lungs from RAGE-overexpressing mice, compared with wild-type control mice. This observation supports previous work where electron microscopy identified the cellular blebbing of alveolar epithelium in embryonic RAGE-overexpressing mice. Assaying for NF-kappa B also revealed elevated nuclear translocation in lungs from transgenic mice compared with control mice. An RT-PCR assessment of genes regulated by NF-kappa B demonstrated the elevated expression of Fas ligand, suggesting increased activity of the Fas-mediated signal transduction pathway in which ligand-receptor interactions trigger cell death. These data provide evidence that the expression of RAGEs must be tightly regulated during homeostatic organogenesis. Further elucidations of the RAGE signaling potentially involved in cell-cycle abnormalities may provide insights into the progression of RAGE-mediated lung diseases.

• 出版日期2012-7