title: Endothelial CSN5 impairs NF-κB activation and monocyte adhesion to endothelial cells and is highly expressed in human atherosclerotic lesions.
abstract: The COP9 signalosome (CSN), a multifunctional protein complex involved in the regulation of cullin-RING-E3 ubiquitin ligases (CRLs), has emerged as a regulator of NF-κB signalling. As NF-κB drives the expression of pro-inflammatory and pro-atherosclerotic genes, we probed the yet unknown role of the CSN, in particular CSN5, on NF-κB-mediated atherogenic responses in endothelial cells. Co-immunoprecipitation in human umbilical vein endothelial cells (HUVECs) revealed the presence of a super-complex between IKK and CSN, which dissociates upon TNF-α stimulation. Furthermore, CSN5 silencing enhanced TNF-α-induced IκB-α degradation and NF-κB activity in luciferase reporter assays. This was paralleled by an increased NF-κB-driven upregulation of atherogenic chemokines and adhesion molecules, as measured by qPCR and flow cytometry, and translated into an enhanced arrest of THP-1 monocytes on TNF-α-stimulated, CSN5-depleted HUVECs. Reverse effects on NF-κB activity and THP-1 arrest were seen upon CSN5 overexpression. Finally, double-immunostaining confirmed the expression of CSN subunits in the endothelium of human atherosclerotic lesions, and revealed an increased expression of CSN5 which correlated with atheroprogression. In conclusion, endothelial CSN5 attenuates NF-κB-dependent pro-inflammatory gene expression and monocyte arrest on stimulated endothelial cells in vitro, suggesting that CSN5 might serve as a negative regulator of atherogenesis.
authors: Institute of Biochemistry and Molecular Cell Biology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany.
authors: Yaw
authors: Y
authors: Asare
authors: Erdenechimeg
authors: E
authors: Shagdarsuren
authors: Johannes A
authors: JA
authors: Schmid
authors: Pathricia V
authors: PV
authors: Tilstam
authors: Jochen
authors: J
authors: Grommes
authors: Omar
authors: O
authors: El Bounkari
authors: Anke K
authors: AK
authors: Schütz
authors: Christian
authors: C
authors: Weber
authors: Menno P J
authors: MP
authors: de Winther
authors: Heidi
authors: H
authors: Noels
authors: Jürgen
authors: J
authors: Bernhagen
mesh_terms: D000075686:COP9 Signalosome Complex; D002448:Cell Adhesion; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D058226:Plaque, Atherosclerotic / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D057705:Transendothelial and Transepithelial Migration; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D010447:Peptide Hydrolases; C501488:COPS5 protein, human; D000075686:COP9 Signalosome Complex