title: Nitro-linoleic acid inhibits vascular smooth muscle cell proliferation via the Keap1/Nrf2 signaling pathway.
abstract: Nitroalkenes, the nitration products of unsaturated fatty acids formed via NO-dependent oxidative reactions, have been demonstrated to exert strong biological actions in endothelial cells and monocytes/macrophages; however, little is known about their effects on vascular smooth muscle cells (VSMCs). The present study examined the role of nitro-linoleic acid (LNO(2)) in the regulation of VSMC proliferation. We observed that LNO(2) inhibited VSMC proliferation in a dose-dependent manner. In addition, LNO(2) induced growth arrest of VSMCs in the G(1)/S phase of the cell cycle with an upregulation of the cyclin-dependent kinase inhibitor p27(kip1). Furthermore, LNO(2) triggered nuclear factor-erythroid 2-related factor 2 (Nrf2) nuclear translocation and activation of the antioxidant-responsive element-driven transcriptional activity via impairing Kelch-like ECH-associating protein 1 (Keap1)-mediated negative control of Nrf2 activity in VSMCs. LNO(2) upregulated the expression of Nrf2 protein levels, but not mRNA levels, in VSMCs. A forced activation of Nrf2 led to an upregulation of p27(kip1) and growth inhibition of VSMCs. In contrast, knock down of Nrf2 using an Nrf2 siRNA approach reversed the LNO(2)-induced upregulation of p27(kip1) and inhibition of cellular proliferation in VSMCs. These studies provide the first evidence that nitroalkene LNO(2) inhibits VSMC proliferation through activation of the Keap1/Nrf2 signaling pathway, suggesting an important role of nitroalkenes in vascular biology.
authors.affiliation: Department of Internal Medicine, Cardiovascular Center, University of Michigan Medical Center, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Luis
authors.initials: L
authors.lastname: Villacorta
authors.forename: Jifeng
authors.initials: J
authors.lastname: Zhang
authors.forename: Minerva T
authors.initials: MT
authors.lastname: Garcia-Barrio
authors.forename: Xi-lin
authors.initials: XL
authors.lastname: Chen
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Freeman
authors.forename: Yuqing E
authors.initials: YE
authors.lastname: Chen
authors.forename: Taixing
authors.initials: T
authors.lastname: Cui
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D047908:Intracellular Signaling Peptides and Proteins; D000072019:Kelch-Like ECH-Associated Protein 1; D008041:Linoleic Acids / Q000008:administration & dosage*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D009574:Nitro Compounds / Q000008:administration & dosage*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: C501855:10-nitro-9,12-octadecadienoic acid; D047908:Intracellular Signaling Peptides and Proteins; C486610:KEAP1 protein, rat; D000072019:Kelch-Like ECH-Associated Protein 1; D008041:Linoleic Acids; D051267:NF-E2-Related Factor 2; D009574:Nitro Compounds; D011506:Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27