期刊
BIOCHEMICAL PHARMACOLOGY
卷 64, 期 5-6, 页码 971-977出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0006-2952(02)01162-0
关键词
transcription factors; NF-kappa B; TNF-alpha; Rho proteins; clostridial toxin; endothelium
Degradation of inhibitor kappa-B (Ikappa-B) followed by translocation of nuclear factor-kappaB (NF-kappaB) into the nucleus and activation of gene expression is essential in tumor necrosis factor-alpha (TNF-alpha)-signaling. In order to analyze the role of Rho proteins in TNF-alpha-induced NF-kappaB-activation in human umbilical cord vein endothelial cells (HUVEC) we used Clostridium difficile toxin B-10463 (TcdB-10463) which inactivates RhoA/Rac1/Cdc42 by glucosylation and Clostridium botulinum C3-toxin which inhibits RhoA/B/C by ADP-ribosylation. Exposure of HUVEC to 10 ng/mLTcdB-10463 or 2.5 mug/mL C3-toxin inhibited TNF-alpha (100 ng/mL)-induced expression of a NF-kappaB-dependent reporter gene. Moreover, preincubation of HUVEC with 10 ng/mLTcdB-10463 reduced TNF-alpha-related expression of interleukin-8 (IL-8), TNF-receptor associated factor-2 (TRAF2), and human inhibitor of apoptosis protein 1 (hIAPI)-mRNA. Blocking of Rho reduced NF-kappaB DNA-binding as shown by electrophoretic mobility shift assays. TcdB-10463 and C3-toxin blocked TNF-alpha-related nuclear translocation of NF-kappaB although IK-Balpha/beta was still degraded. In contrast, TcdB-10463 had no effect on IL-1beta-related NF-kappaB translocation and activation in HUVEC. Neither 1 muM Rho kinase inhibitor Y-27632 nor microfilament depolymerization by 50 ng/mL C. botulinum C2-toxin blocked TNF-alpha-induced degradation of Ikappa-B, nuclear NF-kappaB translocation or expression of a NF-kappaB-dependent reporter gene. Therefore, TNF-alpha-related Ikappa-B-degradation is Rho-independent in HUVEC, whereas a Rho protein-dependent signal is necessary to induce nuclear transport of NF-kappaB in these cells pointing to a novel and unique role of Rho in NF-kappaB-translocation. (C) 2002 Elsevier Science Inc. All rights reserved.
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