title: HDL counterbalance the proinflammatory effect of oxidized LDL by inhibiting intracellular reactive oxygen species rise, proteasome activation, and subsequent NF-kappaB activation in smooth muscle cells.
abstract: Oxidized low-density lipoproteins (oxLDL) exhibit proinflammatory properties and play a role in atherosclerosis plaque formation, rupture, and subsequent thrombosis. OxLDL alter the activity of the transcription factor NF-kappaB that is involved in the expression of immune and inflammatory genes. In contrast, high-density lipoproteins (HDL) are anti-atherogenic and exhibit anti-inflammatory properties. This work aimed to investigate how oxLDL activate NF-kappaB and whether and how HDL may prevent NF-kappaB activation. In cultured rabbit smooth muscle cells, mitogenic concentrations of mildly oxLDL trigger a rapid and transient NF-kappaB activation, which is strongly inhibited by HDL. Growth factors, phosphatidylinositol 3-kinase/Akt, and sphingosine kinase pathways are not implicated in the oxLDL-induced NF-kappaB activation and are not targets of HDL. OxLDL induce reactive oxygen species (ROS) generation and proteasome activation, which are implicated in NF-kappaB activation, as suggested by the inhibitory effect of the antioxidants N-acetyl-L-cysteine and pyrrolidinedithiocarbamate and the proteasome inhibitor PSI. HDL were able to prevent the intracellular ROS rise triggered by oxLDL or H2O2, thereby inhibiting the subsequent proteasome activation, IkappaB degradation, and NF-kappaB activation. In conclusion, the oxLDL-induced NF-kappaB activation involves ROS generation and proteasome activation, both events being inhibited by HDL. This 'antioxidant' and potentially anti-inflammatory effect of HDL may participate in their general anti-atherogenic properties.
authors.affiliation: INSERM U-466, Institut Louis Bugnard, CHU Rangueil, Toulouse, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Robbesyn
authors.forename: Virginie
authors.initials: V
authors.lastname: Garcia
authors.forename: Nathalie
authors.initials: N
authors.lastname: Auge
authors.forename: Otilia
authors.initials: O
authors.lastname: Vieira
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Frisach
authors.forename: Robert
authors.initials: R
authors.lastname: Salvayre
authors.forename: Anne
authors.initials: A
authors.lastname: Negre-Salvayre
mesh_terms: D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D020672:I-kappa B Proteins / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000099157:Sphingosine Kinase
chemical_list: D003546:Cysteine Endopeptidases; D020672:I-kappa B Proteins; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D009097:Multienzyme Complexes; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D046988:Proteasome Endopeptidase Complex; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species; D020794:Receptor Protein-Tyrosine Kinases; D000099157:Sphingosine Kinase; C099252:oxidized low density lipoprotein