Figure 6
Knockdown of TSG-6 mRNA in hMSCs reduces their anti-inflammatory effects. Mice were treated with LPS and four hours later 5 × 105 hMSCs that were mock transfected (hMSCs/No siRNA), transfected with non-silencing siRNA (hMSCs/NS siRNA), or transfected with TSG-6 siRNA (hMSCs/TSG-6 siRNA) were delivered by OA. Human TSG-6 mRNA levels in the lung, as well as markers of inflammation and injury in BAL fluid were assessed 24 hours later. (a) qRT-PCR analyses demonstrated significantly reduced levels of human TSG-6 mRNA in lungs of mice treated with hMSCs/TSG-6 siRNA compared to those treated with hMSCs/No siRNA or hMSCs/NS siRNA. (b) MIP-2 concentrations (c) total cell counts, and (d) MPO activity and (e) total protein concentration in the BAL fluid was attenuated in animals treated with hMSCs/No siRNA or hMSCs/NS siRNA but not hMSCs/TSG-6 siRNA. (f) The percentage of delivered hMSCs in the lung at the time of human TSG-6 mRNA analysis was determined by measuring human GAPDH mRNA levels and calculating the number of cells from a standard curve as previously described [16]. Data are presented as means ± SEM (n = 6 per group). *P < 0.05 compared with LPS + PBS exposed mice; † P < 0.05 compared with mice treated with hMSCs/No siRNA, and ‡ P < 0.05 versus mice treated with hMSCs/NS siRNA.