rhHMGB1-mediated induction of MAP kinases in endothelial cells.

Western blots of HMEC-1 cells treated with rhHMGB1 50 ng/mL for the indicated times were probed with antibodies against the phosphorylated (upper row) and common (lower row) forms of ERK1/2, JNK, and p38. Phospho-ERK 1/2 was mildly expressed at baseline and was strongly induced by rhHMGB1 at 15, 30, and 60 minutes. Phospho-JNK was detected within 5 minutes, reached a peak at 30 minutes, and returned to baseline levels by 90 minutes. Phospho-p38 was detected within 5 minutes, rose to maximum activity at 15 minutes, and remained detectable at 60 minutes. Summary data represents mean ± SEM of densitometry from 5 separate experiments.