Effects of F/G-actin ratio and actin turn-over rate on NADPH oxidase activity in microglia

BMC Immunology

Research Article

Hideki Sumimoto¹  Luise Byg²  Line H Pedersen²  Frederik Vilhardt²  Izabela Rasmussen²  Kazuhiro Suzuki³ 

[1] Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 812-8582, Fukuoka, Japan;Dept. of Cellular and Molecular Medicine, The Panum Institute, Copenhagen University, 2200N, Copenhagen, Denmark;The Division of Biosignaling, National Institute of Health Sciences, 18-1 Kamiyoga 1-Chome, Tokyo, Japan;

关键词: NADPH Oxidase;    Actin Cytoskeleton;    Superoxide Production;    Fluorescence Recovery After Photobleaching;    NADPH Oxidase Activity;   

DOI  :  10.1186/1471-2172-11-44

 received in 2010-06-16, accepted in 2010-09-08,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundMost in vivo studies that have addressed the role of actin dynamics in NADPH oxidase function in phagocytes have used toxins to modulate the polymerization state of actin and mostly effects on actin has been evaluated by end point measurements of filamentous actin, which says little about actin dynamics, and without consideration for the subcellular distribution of the perturbed actin cytoskeleton.ResultsHere, we in addition to toxins use conditional expression of the major actin regulatory protein LIM kinase-1 (LIMK1), and shRNA knock-down of cofilin to modulate the cellular F/G-actin ratio in the Ra2 microglia cell line, and we use Fluorescence Recovery after Photobleaching (FRAP) in β-actin-YFP-transduced cells to obtain a dynamic measure of actin recovery rates (actin turn-over rates) in different F/G-actin states of the actin cytoskeleton. Our data demonstrate that stimulated NADPH oxidase function was severely impaired only at extreme actin recovery rates and F/G-actin ratios, and surprisingly, that any moderate changes of these parameters of the actin cytoskeleton invariably resulted in an increased NADPH oxidase activity.Conclusionmoderate actin polymerization and depolymerization both increase the FMLP and PMA-stimulated NADPH oxidase activity of microglia, which is directly correlated with neither actin recovery rate nor F/G- actin ratio. Our results indicate that NADPH oxidase functions in an enhanced state of activity in stimulated phagocytes despite widely different states of the actin cytoskeleton.

【 授权许可】

Unknown   
© Rasmussen et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.