Fig. 3.
MSC Toll-like receptor 3 (TLR3) activation is mediated through MAPK signaling pathways. A: qRT-PCR analysis of MSC TLR3 expression in response to poly(I:C) treatment. Representative qRT-PCR products were fractionated by agarose gel electrophoresis (left) and relative expression levels derived from CT are illustrated (right, n = 4). B: MSC were treated with 4 μg/ml poly(I:C) for 2–24 h, following which cells were harvested and processed for SDS-PAGE and Western blot analysis. Proteins (45 μg) were loaded in each lane. Representative Western blots of three independent experiments examining p38 MAPK, JNK/SAPK, and ERK1/2 are illustrated. C: digital quantification of the three signaling pathways. Phosphorylation levels represent the ratios of each phosphorylated kinase to the respective total kinase at the time points illustrated. n = 3; *P < 0.05, **P < 0.01, and ***P < 0.001 vs. no poly(I:C) control.