Flow shear stress and atherosclerosis: a matter of site specificity.
It is well accepted that atherosclerosis occurs in a site-specific manner especially at branch points where disturbed blood flow (d-flow) predisposes to the development of plaques. Investigations both in vivo and in vitro have shown that d-flow is pro-atherogenic by promoting oxidative and inflammatory states in the artery wall. In contrast, steady laminar blood flow (s-flow) is atheroprotective by inhibition of oxidative stress and inflammation in the vessel wall. The mechanism for inflammation in endothelial cells (ECs) exposed to d-flow has been well studied and includes redox-dependent activation of apoptosis signal-regulating kinase 1 (ASK1) and Jun NH2-terminal kinase (JNK) that ultimately lead to the expression of adhesive molecules. In contrast, s-flow leads to the activation of the mitogen extracellular-signal-regulated kinase kinase 5/extracellular signal-regulated kinase-5 (MEK5/ERK5) pathway that prevents pro-inflammatory signaling. Important transcriptional events that reflect the pro-oxidant and pro-inflammatory condition of ECs in d-flow include the activation of activator protein 1 (AP-1) and nuclear factor kappaB (NFκB), whereas in s-flow, activation of Krüppel-like factor 2 (KLF2) and nuclear factor erythroid 2-like 2 (Nrf2) are dominant. Recent studies have shown that protein kinase c zeta (PKCζ) is highly activated under d-flow conditions and may represent a molecular switch for EC signaling and gene expression. The targeted modulation of proteins activated in a site-specific manner holds the promise for a new approach to limit atherosclerosis.
Department of Medicine, Aab Cardiovascular Research Institute, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA..
Patrizia
P
Nigro
Jun-Ichi
J
Abe
Bradford C
BC
Berk
D000818:Animals; D050197:Atherosclerosis / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D010641:Phenotype; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D033081:Shear Strength; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical; D000099221:Protein Kinase C zeta
D011493:Protein Kinase C; D017382:Reactive Oxygen Species; D000099221:Protein Kinase C zeta