Activation of Myeloid Dendritic Cells by Up-Regulating RAGE/JAK/STAT Pathway Induced by Cigarette Smoke Exposure in Mice With Emphysema.

Abstract

Objective: To explore the potential role of the RAGE/JAK/STAT pathway along with the activation of myeloid dendritic cells (mDCs) and B cells induced by cigarette smoke exposure in mice. Methods: 57BL/6J mice and RAGEfl/flCD11c-Cre mice were subjected to cigarette smoke for 24 weeks and mated with room air controls. Mice bone marrow-derived dendritic cells (BMDCs) were treated with cigarette smoke extracts (CSEs), CSE with the RAGE inhibitor FPS-ZM1 or CSE with the JAK2 inhibitor AG490. The extent of emphysema in these mice was assessed using the average alveolar lining distance (Lm). Real-time PCR was employed to quantify the mRNA expression levels of RAGE, JAK2, STAT1, STAT3 and STAT5 in lung tissue samples. The levels of IL-6 and IL-1β in mouse serum and BMDC supernatant were quantified using ELISA. Flow cytometry was employed to measure the expression of CD40, CD86, RAGE, p-JAK2, p-STAT1, p-STAT3 and p-STAT5 of lung mDCs and BMDCs in mice. Flow cytometry was employed to identify markers CD69, CD86 and CD138 on pulmonary B cells. Results: Exposing mice to cigarette smoke triggered an exaggerated pulmonary mDCs response and elevated the RAGE/JAK/STAT pathway in both pulmonary mDCs and lung tissue, correlating with enhanced B cells response in lungs. Conditional knockdown of RAGE on dendritic cells (DCs) resulted in a reduction of activity within JAK/STAT pathway, impeded the exaggerated mDCs and B cells responses induced by smoking, down-regulated the serum inflammatory response and mitigated emphysema in cigarette smoke-exposed mice. Within a regulated laboratory setting, BMDCs were activated, leading to the amplification of the RAGE/JAK/STAT pathway in these cells after CSE exposure. FPS-ZM1 and AG490 reduced inflammatory factors in the supernatant and activation of BMDC. Conclusion: In mice, prolonged exposure to cigarette smoke triggers the activation of mDCs by enhancing the RAGE/JAK/STAT pathway. Conditional knockdown of RAGE on DCs can prevent the activation of mDCs and B cells triggered by cigarette smoke, indicating that RAGE could be a potential target for treating smoking-induced emphysema.