Figure 1. SMAD4 participates in endotoxin tolerance development.

A. THP1 cells were treated with 100ng/ml or 10-100ng/ml of LPS for 0, 1, 3, 6 and 24 hours. After a specified period, cells were harvested for Western blot analysis and culture supernatants assessed for TNF-α concentration. Each treatment was executed in triplicates. Results are shown as mean ± SD. B. Cytosolic and nuclear proteins were isolated from the above treated cells and subjected to Western blot analysis with indicated antibodies. All blots were reprobed with anti-β-Actin to show equal loading. All results are representative of three separate experiments. C. THP1 cells were treated with 100ng/ml or 10-100ng/ml of LPS for 0, 2 and 10 min. After a specified period, cells were harvested for Western blot analysis against p-SMAD2, SMAD2 or -β-Actin.