Combination effects of cigarette smoke extract and ambient ultrafine particles on endothelial cells (original) (raw)
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American Journal of Respiratory Cell and Molecular Biology, 2010
Epidemiologic studies have linked exposure to airborne pollutant particulate matter (PM) with increased cardiopulmonary mortality and morbidity. The mechanisms of PM-mediated lung pathophysiology, however, remain unknown. We tested the hypothesis that PM, via enhanced oxidative stress, disrupts lung endothelial cell (EC) barrier integrity, thereby enhancing organ dysfunction. Using PM collected from Ft. McHenry Tunnel (Baltimore, MD), we assessed PM-mediated changes in transendothelial electrical resistance (TER) (a highly sensitive measure of barrier function), reactive oxygen species (ROS) generation, and p38 mitogen-activated protein kinase (MAPK) activation in human pulmonary artery EC. PM induced significant dose (10-100 mg/ml)and time (0-10 h)-dependent EC barrier disruption reflected by reduced TER values. Exposure of human lung EC to PM resulted in significant ROS generation, which was directly involved in PM-mediated EC barrier dysfunction, as N-acetyl-cysteine (NAC, 5 mM) pretreatment abolished both ROS production and barrier disruption induced by PM. Furthermore, PM induced p38 MAPK activation and HSP27 phosphorylation, events that were both attenuated by NAC. In addition, PM-induced EC barrier disruption was partially prevented by the p38 MAP kinase inhibitor SB203580 (10 mM) as well as by reduced expression of either p38 MAPK b or HSP27 (siRNA). These results demonstrate that PM induces ROS generation in human lung endothelium, resulting in oxidative stress-mediated EC barrier disruption via p38 MAPK-and HSP27-dependent pathways. These findings support a novel mechanism for PM-induced lung dysfunction and adverse cardiopulmonary outcomes.
Arteriosclerosis, Thrombosis, and Vascular Biology, 2004
Objective-Endothelial dysfunction is an early manifestation of cigarette smoke (CS) toxicity. We have previously demonstrated that CS impairs nitric oxide (NO)-mediated endothelial function via increased generation of superoxide anion (O 2 . ). In these studies, we investigated whether stable compounds present in CS activate specific pathways responsible for the increased endothelial O 2 . production.
Particle and Fibre Toxicology, 2010
Background: Epidemiological evidence supports the association between exposure to ambient particulate matter (PM) and cardiovascular diseases. Chronic exposure to ultrafine particles (UFP; D p <100 nm) is reported to promote atherosclerosis in ApoE knockout mice. Atherogenesis-prone factors induce endothelial dysfunction that contributes to the initiation and progression of atherosclerosis. We previously demonstrated that UFP induced oxidative stress via c-Jun N-terminal Kinases (JNK) activation in endothelial cells. In this study, we investigated pro-inflammatory responses of human aortic endothelial cells (HAEC) exposed to UFP emitted from a diesel truck under an idling mode (UFP1) and an urban dynamometer driving schedule (UFP2), respectively. We hypothesize that UFP1 and UFP2 with distinct chemical compositions induce differential pro-inflammatory responses in endothelial cells.
Atherosclerosis, 2005
The association between cigarette smoking and atherogenesis is well established. Inflammatory cells may participate in atherogenesis via activation of the NADPH oxidase and the subsequent production of reactive oxygen species (ROS), which exacerbates endothelial injury. However, little is known about the ability of cigarette smoke (CS) to modulate NADPH oxidase protein function. In this study, we investigated the ability of a CS extract derived from a high tar cigarette to alter human neutrophil ROS production and the translocation of two NADPH oxidase proteins, p47phox and p67phox.
Exposure to PM2.5 has been strongly linked with the endothelial dysfunction. However, the underlying mechanism of PM2.5 on vascular endothelial function is still poorly understood. This study was aimed to explore the toxic effect and underlying mechanism of PM2.5 on human umbilical vein endothelial cells (HUVECs). The decreased of cell viability and increased of LDH activity were observed in PM2.5-treated HUVECs in a dose-dependent manner. The productions of ROS, MDA, and the inhibition of SOD activity were also triggered by PM2.5 in HUVECs. In addition, PM2.5 increased the intracellular levels of proinflammatory cytokines (IL-6, TNF-a, IL-1β, IL-8 and CRP), cell adhesion molecules (ICAM-1, VCAM-1) and tissue factor (TF), resulted in endothelial activation. For in-depth study, the protein levels of IL-6, JAK1 and STAT3 were significantly up-regulated while the expressions of JAK2 and SOCS1 were gradually down-regulated in PM2.5-treated HUVECs with a dose-dependent way. Our results demonstrated that PM2.5 triggered endothelial activation via the upregulation of IL-6 dependent JAK1/STAT3 signaling pathway. It will provide new insights into the toxic effect and mechanisms of cardiovascular diseases triggered by ambient air pollution.
2011
Chronic exposure to ambient airborne particulate matter of <2.5 m (PM 2.5) increases cardiovascular risk. The mechanisms by which inhaled ambient particles are sensed and how these effects are systemically transduced remain elusive. Objective: To investigate the molecular mechanisms by which PM 2.5 mediates inflammatory responses in a mouse model of chronic exposure. Methods and Results: Here, we show that chronic exposure to ambient PM 2.5 promotes Ly6C high inflammatory monocyte egress from bone-marrow and mediates their entry into tissue niches where they generate reactive oxygen species via NADPH oxidase. Toll-like receptor (TLR)4 and Nox2 (gp91 phox) deficiency prevented monocyte NADPH oxidase activation in response to PM 2.5 and was associated with restoration of systemic vascular dysfunction. TLR4 activation appeared to be a prerequisite for NAPDH oxidase activation as evidenced by reduced p47 phox phosphorylation in TLR4 deficient animals. PM 2.5 exposure markedly increased oxidized phospholipid derivatives of 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphorylcholine (oxPAPC) in bronchioalveolar lavage fluid. Correspondingly, exposure of bone marrow-derived macrophages to oxPAPC but not PAPC recapitulated effects of chronic PM 2.5 exposure, whereas TLR4 deficiency attenuated this response. Conclusions: Taken together, our findings suggest that PM 2.5 triggers an increase in oxidized phospholipids in lungs that then mediates a systemic cellular inflammatory response through TLR4/NADPH oxidase-dependent mechanisms. (Circ Res. 2011;108:716-726.
Cardiovascular Research, 2011
Time for primary review: 35 days Aims Cigarette smoking engenders inflammation and endothelial dysfunction, processes implicated in atherothrombotic disease. We hypothesized that an interaction between inflammatory cytokines in smokers' blood and circulating components of cigarette smoke is necessary to induce reactive oxygen species (ROS) and cyclooxygenase-2 (COX-2) in endothelium. We then explored the molecular mechanisms involved in these effects. Methods and results Serum from nine healthy active smokers (AS) compared with serum from nine non-smokers (NS) showed higher levels of interleukin-1beta (IL-1b) and tumour necrosis factor-alpha (TNF-a) and a greater ability to induce ROS production, p47phox translocation to the plasma membrane, and COX-2 mRNA and protein expression in endothelial cells (ECs). Similar results were obtained in vivo and in vitro after treatment with aqueous extracts of cigarette smoke plus IL-1b and TNF-a(TS/IL-1b/TNF-a). In ECs increased ROS production and COX-2 mRNA induced by serum from AS correlated positively with their serum levels of IL-1b and TNF-a. Moreover, a positive correlation was observed between ROS generation and COX-2 mRNA. Simultaneous immuno-neutralization of IL-1b and TNF-a prevented endothelial dysfunction induced by serum from AS. Inhibitors of NADPH oxidase and/or p47phox siRNA diminished ROS production and COX-2 expression as well as phosphorylation of p38 mitogen-activated protein kinase (p38MAPK) and Akt mediated either by AS serum or by TS/IL-1b/TNF-a. Finally, direct inhibition of p38MAPK and Akt activity also abolished COX-2 expression mediated by both types of stimuli. Our results suggest a crucial role played by interactions between inflammatory cytokines and tobacco smoke in the induction of endothelial dysfunction.
Circulation Research, 2011
Rationale: Chronic exposure to ambient air-borne particulate matter of <2.5 μm (PM 2.5 ) increases cardiovascular risk. The mechanisms by which inhaled ambient particles are sensed and how these effects are systemically transduced remain elusive. Objective: To investigate the molecular mechanisms by which PM 2.5 mediates inflammatory responses in a mouse model of chronic exposure. Methods and Results: Here, we show that chronic exposure to ambient PM 2.5 promotes Ly6C high inflammatory monocyte egress from bone-marrow and mediates their entry into tissue niches where they generate reactive oxygen species via NADPH oxidase. Toll-like receptor (TLR)4 and Nox2 (gp91 phox ) deficiency prevented monocyte NADPH oxidase activation in response to PM 2.5 and was associated with restoration of systemic vascular dysfunction. TLR4 activation appeared to be a prerequisite for NAPDH oxidase activation as evidenced by reduced p47 phox phosphorylation in TLR4 deficient animals. PM 2.5 exposure m...
Antioxidants & redox signaling, 2003
Reactive oxygen species (ROS)-mediated compromise of endothelial barrier integrity has been implicated in a number of pulmonary disorders, including adult respiratory distress syndrome, pulmonary edema, and vasculitis. The mechanisms by which ROS increase endothelial permeability are unclear. We hypothesized that ROS-induced changes in cellular redox status (thiols) may contribute to endothelial barrier dysfunction. To test this hypothesis, we used N-acetylcysteine (NAC) and diamide to modulate intracellular levels of cellular glutathione (GSH) and investigated hydrogen peroxide (H(2)O(2))-mediated mitogen-activated protein kinase (MAPK) activation and transendothelial electrical resistance (TER). Exposure of bovine lung microvascular endothelial cells (BLMVECs) to H(2)O(2), in a dose- and time-dependent fashion, increased endothelial permeability. Pretreatment of BLMVECs with NAC (5 mM) for 1 h resulted in partial attenuation of H(2)O(2)-induced TER (a measure of increase in permea...
Analytical and Bioanalytical Chemistry, 2009
In vitro systems are frequently used to study mechanisms of mainstream cigarette smoke (MS)induced lung injury. Traditional methods of exposure involve the capture of MS particulate phase with filter pads or bubbling MS through phosphate buffered saline (PBS) or cell culture medium. Although useful for in vitro experiments, these exposure methods may fail to capture potential interactions between the gas and particulate phases. To better understand the effect of MS on the human airway, in vitro whole smoke exposure systems that utilize freshly generated whole smoke are needed. Here we report the characterization of a new in vitro whole smoke exposure system (Burghart Mimic Smoker-01 (MSB-01)). This system uses a smoke distribution manifold to simultaneously deliver MS to each well of a 96-well plate. Intraday and interday variations for particulate matter deposition were less than 5% and 13% respectively.