Physiological levels of shear stress alter the genetic program cultured endothelial cells and are associated with reduced cellular turnover rates formation atherosclerotic lesions in vivo. To test hypothesis that (15 dynes/cm2) interferes programmed cell death, apoptosis was induced human umbilical venous (HUVEC) by tumor necrosis factor-alpha (TNF-alpha). Apoptosis quantified ELISA specific for histone-associated DNA-fragments confirmed demonstrating pattern internucleosomal...

The nicotinamide adenine dinucleotide (NAD + )-dependent histone deacetylase Sir2 regulates life-span in various species. Mammalian homologs of are called sirtuins (SIRT1–SIRT7). In an effort to define the role vascular homeostasis, we found that among SIRT family, SIRT1 uniquely angiogenesis signaling. We show is highly expressed vasculature during blood vessel growth, where it controls angiogenic activity endothelial cells. Loss function blocks sprouting and branching morphogenesis cells...

In cultured human endothelial cells, physiological levels of NO prevent apoptosis and interfere with the activation caspase cascade. vitro data have demonstrated that inhibits activity caspase-3 by S-nitrosation enzyme. Here we present evidence for in vivo occurrence functional relevance this novel antiapoptotic mechanism. To demonstrate cysteine residue Cys-163 is S-nitrosated, cells were transfected Myc-tagged p17 subunit caspase-3. After incubation different donors, was immunoprecipitated...

Abstract —Fluid shear stress alters the morphology and function of endothelium by activating several kinases. Furthermore, potently inhibits apoptosis endothelial cells. Since activation Akt kinase has been shown to prevent cell death, we investigated effects on phosphorylation. To test hypothesis that interacts with pathway, human umbilical venous cells were exposed laminar (15 dyne/cm 2 ). Western blotting specific antibodies against phosphorylated demonstrated a time-dependent stimulation...

Endothelial progenitor cells (EPCs) play an important role in postnatal neovascularization of ischemic tissue. Ex vivo expansion EPCs might be useful for potential clinical cell therapy myocardial ischemia. However, cultivation primary leads to cellular aging (senescence), thereby severely limiting the proliferative capacity. Therefore, we investigated whether statins able prevent senescence EPCs. were isolated from peripheral blood and characterized. After ex cultivation, became senescent...

Aging is associated with a rise in intracellular reactive oxygen species (ROS) and loss of telomerase reverse transcriptase activity. Incubation H 2 O induced the nuclear export (TERT) into cytosol Src-family kinase–dependent manner. Therefore, we investigated hypothesis that age-related increase may induce TERT contribute to endothelial cell senescence. Continuous cultivation cells resulted an increased endogenous formation ROS starting after 29 population doublings (PDL). This was...

Background— The underlying molecular mechanisms of the vasculoprotective effects physical exercise are incompletely understood. Telomere erosion is a central component aging, and telomere-associated proteins regulate cellular senescence survival. This study examines exercising on vascular telomere biology endothelial apoptosis in mice long-term endurance training humans. Methods Results— C57/Bl6 were randomized to voluntary running or no wheel conditions for 3 weeks. Exercise upregulated...

Objective— The enzyme telomerase and its catalytic subunit the reverse transcriptase (TERT) are important for maintenance of telomere length in nucleus. Recent studies provided evidence a mitochondrial localization TERT. Therefore, we investigated exact TERT within mitochondria function. Methods Results— Here, demonstrate that is localized matrix mitochondria. binds to DNA at coding regions ND1 ND2. Binding protects against ethidium bromide–induced damage. increases overall respiratory chain...

Abstract —Reactive oxygen species have been implicated in the pathogenesis of atherosclerosis, hypertension, and restenosis, part by promoting vascular smooth muscle cell (VSMC) growth. Many VSMC growth factors are secreted act an autocrine manner. Here we demonstrate that cyclophilin A (CyPA), a member immunophilin family, is VSMCs response to oxidative stress mediates extracellular signal–regulated kinase (ERK1/2) activation reactive species. Human recombinant CyPA can mimic effects...

Background Oxidized LDL (oxLDL) is believed to play a key role as triggering molecule that causes injury the endothelium an early event in atherogenesis. However, mechanisms by which oxLDL injures endothelial cells are entirely unknown. We speculate may activate cellular suicide pathway leads apoptosis. Methods and Results Human umbilical venous (HUVEC) were incubated with increasing doses of native or for 18 hours. Apoptosis HUVEC was measured ELISA specific histone-associated DNA fragments...

Abstract Angiotensin II (Ang II) importantly contributes to the pathobiology of atherosclerosis. Since endothelial injury is a key event early in pathogenesis atherosclerosis, we tested hypothesis that Ang may injure cells by activation cellular suicide pathways leading apoptosis. Human umbilical venous (HUVECs) were incubated with increasing doses for 18 hours. Apoptosis HUVECs was measured ELISA specific histone-associated DNA fragments and confirmed laddering nuclear staining....

Advanced aging leads to impaired endothelial NO synthesis and enhanced cell apoptosis; therefore, we investigated the sensitivity of aged cells toward apoptotic stimuli determined role NO. Human umbilical vein (HUVECs) were cultured until 14th passage. In cells, oxLDL tumor necrosis factor-alpha-induced apoptosis caspase-3-like activity significantly more than 3-fold compared with young (passage 3). Because contributes protection against death via S-nitrosylation caspases, synthase (eNOS)...

Transplantation of bone marrow cells as well circulating endothelial progenitor (EPC) enhances neovascularization after ischemia. The chemokine receptor CXCR4 is essential for migration and homing hematopoietic stem cells. Therefore, we investigated the role its downstream signaling cascade angiogenic capacity cultured human EPC. Ex vivo, differentiated EPC derived from peripheral blood abundantly expressed CXCR4. Incubation healthy volunteers with neutralizing antibodies against profoundly...

Physiological levels of shear stress alter the genetic program cultured endothelial cells and reduce cell turnover in vivo. To test hypothesis that interferes with programmed death, apoptosis was induced human umbilical venous by growth factor withdrawal or incubation tumor necrosis alpha (TNFalpha) for 18 h. Apoptosis quantified ELISA specific histone-associated DNA fragments confirmed demonstrating pattern internucleosomal fragmentation detected electrophoresis immunohistochemical...

The ratio of proapoptotic versus antiapoptotic Bcl-2 members is a critical determinant that plays significant role in altering susceptibility to apoptosis. Therefore, reduction protein levels response proximal signal transduction events may switch on the apoptotic pathway. In endothelial cells, tumor necrosis factor alpha (TNF-α) induces dephosphorylation and subsequent ubiquitin-dependent degradation Bcl-2. Here, we investigate different putative phosphorylation sites facilitate...

Injury of the endothelial cells by induction apoptotic cell death may play an important role in pathophysiology atherosclerosis and progression inflammatory diseases. Here, we demonstrate essential for ubiquitin-dependent proteasome complex stimulus-induced degradation antiapoptotic protein Bcl-2. Bcl-2 is specifically degraded after stimulation human with tumor necrosis factor (TNF)-α a process that inhibited specific inhibitors. In addition, mutation potential ubiquitin-acceptor amino...

The regeneration of new myocardium by stem or progenitor cells is an important therapeutic option. Cellular nuclear fusion considered as alternative to cell reprogramming transdifferentiation. However, the generation hybrid may also be a consequence transient transmembrane exchange proteins and organelles between cells. Therefore, we investigated formation intercellular connections, which allow transport macromolecular structures labeled adult human endothelial (EPC) GFP-expressing neonatal...

c-Jun NH2-terminal kinase (JNK) is activated by a number of cellular stimuli such as inflammatory cytokines and environmental stresses. Reactive oxygen species also cause activation JNK; however, the signaling cascade that leads to JNK remains be elucidated. Because recent reports showed expression Cas, putative Src substrate, stimulates activation, we hypothesized family Cas would involved in reactive species. An essential role for both was demonstrated. First, specific tyrosine inhibitor,...

AbstractThe regulation of telomerase reverse transcriptase (TERT) plays an important role in the proliferative capacity and survival cells. Here, we report that exogenously as well endogenously induced oxidative stress leads to translocation endogenous overexpressed human TERT from nucleus into cytosol. is transported through nuclear pores a leptomycin-sensitive Ran GTPase-dependent process. H2O2-induced export preceded by tyrosine phosphorylation at position 707 prevented Src kinase family...

Background— Cultivation of endothelial progenitor cells (EPCs) leads to premature replicative senescence, limiting ex vivo expansion for potential clinical cell therapy. Recent studies have linked senescence the dysfunction telomeres, “ends” chromosomes, via so-called mitotic clock or culture-induced stress. The purpose this study was elucidate a possible role telomere biology in functional augmentation EPCs by statins. Methods and Results— Human were isolated from peripheral blood. Using...