HIF-1α activation results in actin cytoskeleton reorganization and modulation of Rac-1 signaling in endothelial cells

Cell Communication and Signaling

Research

Iwona Cicha¹  Kai-Uwe Eckardt²  Alexander Weidemann²  Margot Rehm²  Margarete Goppelt-Struebe²  Johannes Breyer³  Christoph Daniel⁴  Klaudia Giehl⁵ 

[1] Department of Cardiology and Angiology, Universitätsklinikum Erlangen, Universität Erlangen-Nürnberg, Schwabachanlage 10, 91054, Erlangen, Germany;Department of Nephrology and Hypertension, Universitätsklinikum Erlangen, Universität Erlangen-Nürnberg, Loschgestrasse 8, 91054, Erlangen, Germany;Department of Nephrology and Hypertension, Universitätsklinikum Erlangen, Universität Erlangen-Nürnberg, Loschgestrasse 8, 91054, Erlangen, Germany;Department of Urology, University of Regensburg, Regensburg, Germany;Department of Nephropathology, Universitätsklinikum Erlangen, Universität Erlangen-Nürnberg, Krankenhausstrasse 8-10, 91054, Erlangen, Germany;Molecular Oncology of Solid Tumors, Internal Medicine IV/V, Justus-Liebig-University Giessen, Schubertstr. 81 – BFS, 35392, Giessen, Germany;

关键词: Hypoxia-inducible transcription factor;    endothelial cell;    cytoskeleton;    migration;    Rho kinase;    Rac-1;    p21-activated kinase;    prolyl hydroxylase inhibitor;    von Hippel-Lindau protein;    oxygen;   

DOI  :  10.1186/1478-811X-11-80

 received in 2013-05-14, accepted in 2013-10-10,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundHypoxia is a major driving force in vascularization and vascular remodeling. Pharmacological inhibition of prolyl hydroxylases (PHDs) leads to an oxygen-independent and long-lasting activation of hypoxia-inducible factors (HIFs). Whereas effects of HIF-stabilization on transcriptional responses have been thoroughly investigated in endothelial cells, the molecular details of cytoskeletal changes elicited by PHD-inhibition remain largely unknown. To investigate this important aspect of PHD-inhibition, we used a spheroid-on-matrix cell culture model.ResultsMicrovascular endothelial cells (glEND.2) were organized into spheroids. Migration of cells from the spheroids was quantified and analyzed by immunocytochemistry. The PHD inhibitor dimethyloxalyl glycine (DMOG) induced F-actin stress fiber formation in migrating cells, but only weakly affected microvascular endothelial cells firmly attached in a monolayer. Compared to control spheroids, the residual spheroids were larger upon PHD inhibition and contained more cells with tight VE-cadherin positive cell-cell contacts. Morphological alterations were dependent on stabilization of HIF-1α and not HIF-2α as shown in cells with stable knockdown of HIF-α isoforms. DMOG-treated endothelial cells exhibited a reduction of immunoreactive Rac-1 at the migrating front, concomitant with a diminished Rac-1 activity, whereas total Rac-1 protein remained unchanged. Two chemically distinct Rac-1 inhibitors mimicked the effects of DMOG in terms of F-actin fiber formation and orientation, as well as stabilization of residual spheroids. Furthermore, phosphorylation of p21-activated kinase PAK downstream of Rac-1 was reduced by DMOG in a HIF-1α-dependent manner. Stabilization of cell-cell contacts associated with decreased Rac-1 activity was also confirmed in human umbilical vein endothelial cells.ConclusionsOur data demonstrates that PHD inhibition induces HIF-1α-dependent cytoskeletal remodeling in endothelial cells, which is mediated essentially by a reduction in Rac-1 signaling.

【 授权许可】

Unknown   
© Weidemann et al.; licensee BioMed Central Ltd. 2013. 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.