title: Cholesterol Enrichment Impairs Capacitative Calcium Entry, eNOS Phosphorylation & Shear Stress-Induced NO Production.
abstract: Endothelial dysfunction, characterized by decreased production or availability of nitric oxide (NO), is widely believed to be the hallmark of early-stage atherosclerosis. In addition, hypercholesterolemia is considered a major risk factor for development of atherosclerosis and is associated with impaired flow-induced dilation. However, the mechanism by which elevated cholesterol levels leads to decreased production of NO is unclear. NO is released in response to shear stress and agonist-evoked changes in intracellular calcium. Although calcium signaling is complex, we have previously shown that NO production by endothelial nitric oxide synthase (eNOS) is preferentially activated by calcium influxviastore-operated channels. We hypothesized that cholesterol enrichment altered this signaling pathway (known as capacitive calcium entry; CCE) ultimately leading to decreased NO. Our results show that cholesterol enrichment abolished ATP-induced eNOS phosphorylation and attenuated the calcium response by the preferential inhibition of CCE. Furthermore, cholesterol enrichment also inhibited shear stress-induced NO production and eNOS phosporylation, consistent with our previous results showing a significant role for ATP autocrine stimulation and subsequent activation of CCE in the endothelial flow response.
authors.affiliation: Department of Pathology & Laboratory Medicine, Lewis Katz School of Medicine at Temple University, 3500N. Broad St., Philadelphia, PA 19140, USA.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Andrews
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Market St., Philadelphia, PA 19104, USA.
authors.forename: Tenderano T
authors.initials: TT
authors.lastname: Muzorewa
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Market St., Philadelphia, PA 19104, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Zaccheo
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Market St., Philadelphia, PA 19104, USA.
authors.forename: Donald G
authors.initials: DG
authors.lastname: Buerk
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Market St., Philadelphia, PA 19104, USA.
authors.forename: Dov
authors.initials: D
authors.lastname: Jaron
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, 3141 Market St., Philadelphia, PA 19104, USA.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Barbee
keywords: Atherosclerosis; Capacitative calcium entry; Cholesterol; Endothelial cells; Nitric oxide; Shear stress