Figure 4

TLR gene expression of MSCs at basal state and under osteogenic differentiation with and without LPS exposure. (A) Quantitative PCR revealed that TLR4 expression was significantly higher after 12 days of incubation in osteogenesis-induction medium than after shorter periods, and higher than after 12 days of constitutive expression. (B) Quantitative PCR revealed that TLR2 expression in MSCs was significantly higher after 12 days of incubation in osteogenesis-induction medium than after shorter periods, and higher than after 12 days of constitutive expression. (C) TLR4 expression in MSCs cultured under osteogenic conditions was lower on Day 12 after exposure to LPS (1 μg/mL) for 3 or 12 days. (D) TLR2 expression in MSCs cultured under osteogenic conditions was lower on Day 12 after exposure to LPS (1 μg/mL) for 12 days, but not after 3-day LPS exposure. The data are pooled from three experiments, each done in duplicates, and expressed as mean ± SEM. * P < 0.05; ** P < 0.01; *** P < 0.001.