Dexamethasone-conjugated polyethylenimine/MIF siRNA complex regulation of particulate matter-induced airway inflammation

Abstract Inhalation of airborne particulate matter (PM), such as silicon dioxide (SiO 2 ) and titanium dioxide (TiO 2 ), induces acute lung inflammation. siRNA therapy has been proposed as a method to repair acute lung inflammation. To determine whether DEXA-PEI/MIF siRNA contributes to SiO 2 -induced acute lung inflammation repair, we administered Dexa-PEI/MIF siRNA in SiO 2 -treated Beas-2b cells and instilled DEXA-PEI-MIF siRNA intratracheally in mice with SiO 2 -induced acute lung inflammation. Using genetic (MIF mRNA RT-PCR), histological (HE in contrast, the decrease of MIF mRNA using DEXA-PEI/MIF siRNA effectively lowered Muc5ac in SiO 2 -treated cells and mice. These results suggest that DEXA-PEI plays a role in delivering siRNA to the nucleus as a carrier and limits the extent of acute lung inflammation. MIF siRNA also contributed to the reparative lung response in SiO 2 -induced pulmonary inflammation.