Genome-wide analysis of microRNA-22 responsive gene expression in lung antigen presenting cells in response to chronic nanoparticulate carbon black exposure

Analysis of lung CD11c+ antigen presenting cells (APCs) isolated from wildtype or Mir22-/- mice exposed to nanoparticulate carbon black (nCB) for one month. MiR-22 plays important roles in nCB induced experimental emphysema through regulating APC activation. Results provide insight into the biological role and target genes of miR-22. Smoking-related emphysema is a chronic inflammatory disease driven by T helper 17 (TH17) cells through molecular mechanisms that remain obscure. Here we have explored the role of microRNA-22 (miR-22) in emphysema. MiR-22 was upregulated in lung myeloid dendritic cells (mDCs) of smokers with emphysema and antigen-presenting cells (APCs) of mice exposed to smoke or nanoparticulate carbon black (nCB) through a mechanism involving NF-kappaB. MiR-22-deficient mice, but not wild-type, showed attenuated TH17 responses and failed to develop emphysema after exposure to either smoke or nCB. We further show that miR-22 controls APC activation and TH17 responses through activation of AP-1 transcription factor complexes and histone deacetylase (HDAC) 4. Thus, miR-22 is a critical regulator of both emphysema and TH17 responses. Lung APCs were isolated from PBS (reference groups) or nCB exposed wildtype or Mir22-/- mice, total four groups. There were three replicates in each group.