TNF-α-induced ICAM-1 expression is mediated via the formation of a TNFR1/TRAF2 complex.

<p>(A) Human RPECs were pretreated with a TNFR neutralizing antibody, and then incubated with TNF-α for 6 h. The protein expression of ICAM-1 was determined by Western blot. (B) RPECs were pretreated with the neutralizing antibody of TNFR for 1 h, and then incubated with TNF-α for 6 h. The THP-1 cells adherence was measured. (C) Cells were transfected with siRNA of scrambled, TNFR1, or TRAF2, and then incubated with TNF-α for 6 h. The protein levels of TNFR1, TRAF2, and ICAM-1 were determined by Western blot. (D) Cells were incubated with TNF-α (15 ng/ml) for various time intervals. The cell lysates were subjected to immunoprecipitation using an anti-TRAF2 antibody, and then the immunoprecipitates were analyzed by Western blot using an anti-TRAF2 or anti-TNFR1 antibody. (E) Cells were treated without or with TNF-α for 6 h. The expression of TNFR1 was determined. Data are expressed as mean±S.E.M. of three independent experiments. ^<i>*</i><i>P</i><0.05; ^#<i>P</i><0.01, as compared with the cells exposed to TNF-α alone.