Study on the expression of IkappaB-alpha protein in TNF-alpha induced apoptosis of U937 cells.

Weihua Chen; Guangjie Peng; Aiping Tang; Kaiyan Wang; Muxiang Zhou; Lingyi Wang

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Study on the expression of IkappaB-alpha protein in TNF-alpha induced apoptosis of U937 cells.

Author: Weihua CHEN ¹ ; Guangjie PENG ; Aiping TANG ; Kaiyan WANG ; Muxiang ZHOU ; Lingyi WANG
Author Information

1. Department of Pediatrics, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
Publication Type:Journal Article
MeSH: Apoptosis; drug effects; Down-Regulation; Humans; NF-kappa B; metabolism; Tumor Necrosis Factor-alpha; metabolism; U937 Cells
From: Chinese Journal of Hematology 2002;23(7):353-355
CountryChina
Language:English
Abstract:
OBJECTIVETo investigate the TNF-alpha induced apoptosis of U937 cells, the expression, degradation and subcellular localization of IkappaB-alpha, and its degradation mechanism.
METHODChanges and subcellular loca-lization of IkappaB-alpha were observed by fluorescence microscopy, expression and degradation of IkappaB-alpha protein with N-tosyl-L-phenylalanylchloromethyl ketone (TPCK protease inhibitor) blocking test and apoptosis of U937 cell by flow cytometry.
RESULTS(1) immunolfluorescence assay showed that IkappaB-alpha localized in cytoplasm only. (2) The level of IkappaB-alpha protein was downregulated after TNF-alpha stimulation, flow cytometry also confirmed the downregulation. (3) The downregulation of IkappaB-alpha protein levels in TNF-alpha induced apoptosis was partially inhibited by TPCK. (4) The apoptosis rate of U937 cells induced by TNF-alpha was (60.73 +/- 1.61)%.
CONCLUSION(1) Degradation of IkappaB-alpha protein during TNF-alpha induced apoptosis of U937 cells suggested the activation of NF-kappaB. (2) TPCK sensitive protease plays an important role in the degradation of IkappaB-alpha protein. (3) TPCK sensitive protease also involved in the apoptosis of U937 cells induced by TNF-alpha.