Receptors for advanced glycation end-products (RAGE) are multi-ligand cell surface receptors of the immunoglobin family expressed by epithelium and macrophages. RAGE expression increases following ligand binding and when diverse cells are exposed to a variety of insults including cigarette smoke extract (CSE). The current research sought to characterize the pro-inflammatory contributions of RAGE expressed by alveolar macrophages (AMs) following CSE exposure. Acute exposure of mice to CSE via nasal instillation revealed diminished bronchoalveolar lavage (BAL) cellularity and fewer AMs in RAGE null mice compared to controls. Primary AMs were obtained from BAL, exposed to CSE in vitro, and RNA, DNA, and protein were analyzed. CSE significantly increased RAGE expression by wild type AMs. Employing ELISAs, wild type AMs exposed to CSE had increased levels of active Ras, a small GTPase that perpetuates pro-inflammatory signaling. Conversely, RAGE null AMs had less Ras activation compared to wild type AMs after exposure to CSE. In RAGE null AMs, assessment of p38 MAPK and NF-κB, important intracellular signaling intermediates induced during an inflammatory response, revealed CSE-induced inflammation occurs at least in part via RAGE signaling. For example, activated p38 was diminished in RAGE null AMs compared to controls and assessment of phosphorylated NF-κB in CSE exposed RAGE null AMs suggest lessened nuclear translocation of NF-κB compared to wild type AMs exposed to CSE. Importantly, quantitative RT-PCR revealed that mRNA expression of pro-inflammatory cytokines including TNF-α and IL-1β were detectably decreased and analysis of secreted proteins by ELISA displayed diminished IL-1β in RAGE null AMs exposed to CSE compared to CSE-exposed wild type AMs. These results reveal that primary AMs orchestrate CSE-induced inflammation, at least in part, via RAGE-mediated mechanisms.



College and Department

Life Sciences; Physiology and Developmental Biology



Date Submitted


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RAGE, lung, macrophages, tobacco smoke