Oxidative burst and NO generation as initial response to ischemia in flow-adapted endothelial cells

2001 ◽  
Vol 280 (5) ◽  
pp. H2126-H2135 ◽  
Author(s):  
Yefim Manevich ◽  
Abu Al-Mehdi ◽  
Vladimir Muzykantov ◽  
Aron B. Fisher
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Oxidative Burst ◽  
Initial Response ◽  
Membrane Depolarization ◽  
No Synthase ◽  
Potential Production ◽  
Perfusion Chamber ◽  
Intracellular Ca ◽  
Static Conditions

Shear stress modulates endothelial physiology, yet the effect(s) of flow cessation is poorly understood. The initial metabolic responses of flow-adapted bovine pulmonary artery endothelial cells to the abrupt cessation of flow (simulated ischemia) was evaluated using a perfusion chamber designed for continuous spectroscopy. Plasma membrane potential, production of reactive O2 species (ROS), and intracellular Ca2+ and nitric oxide (NO) levels were measured with fluorescent probes. Within 15 s after flow cessation, flow-adapted cells, but not cells cultured under static conditions, showed plasma membrane depolarization and an oxidative burst with generation of ROS that was inhibited by diphenyleneiodonium. EGTA-inhibitable elevation of intracellular Ca2+ and NO were observed at ∼30 and 60 s after flow cessation, respectively. NO generation was decreased in the presence of inhibitors of NO synthase and calmodulin. Thus flow-adapted endothelial cells sense the altered hemodynamics associated with flow cessation and respond by plasma membrane depolarization, activation of NADPH oxidase, Ca2+ influx, and activation of Ca2+/calmodulin-dependent NO synthase. This signaling response is unrelated to cellular anoxia.

An immediate endothelial cell signaling response to lung ischemia

2001 ◽  
Vol 281 (4) ◽  
pp. L993-L1000 ◽  
Author(s):  
Chun Song ◽  
Abu B. Al-Mehdi ◽  
Aron B. Fisher
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Initial Response ◽  
Membrane Depolarization ◽  
Initial Increase ◽  
Amplex Red ◽  
Vascular Space ◽  
Endothelial Response ◽  
Intracellular Ca

Abrupt cessation of lung perfusion induces a rapid endothelial response that is not associated with anoxia but reflects loss of normal shear stress. This response includes membrane depolarization, H2O2generation, and increased intracellular Ca2+. We evaluated these parameters immediately upon nonhypoxic ischemia using fluorescence videomicroscopy to image in situ endothelial cells in isolated, ventilated rat lungs. Lungs labeled with 4-{2-[6-(dioctylamino)-2-naphthalenyl]ethenyl}1-(3-sulfopropyl)-pyridinium (di-8-ANEPPS; a membrane potential probe), Amplex Red (an extracellular H2O2probe), or fluo 3-AM (a Ca2+indicator) were subjected to control perfusion followed by global ischemia. Endothelial di-8-ANEPPS fluorescence increased significantly within the first second of ischemia and stabilized at 15 s, indicating membrane depolarization by ∼17 mV; depolarization was blocked by preperfusion with the K+channel agonist lemakalim. Increased H2O2, inhibitable by catalase, was detected in the vascular space at 1–2 s after the onset of ischemia. Increased intracellular Ca2+was detected 10–15 s after the onset of ischemia; the initial increase was inhibited by preperfusion with thapsigargin. Thus the temporal sequence of the initial response of endothelial cells in situ to loss of shear stress (i.e., ischemia) is as follows: membrane depolarization, H2O2release, and increased intracellular Ca2+.

scholarly journals Functional Relevance of Golgi- and Plasma Membrane-Localized Endothelial NO Synthase in Reconstituted Endothelial Cells

2006 ◽  
Vol 26 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Qian Zhang ◽  
Jarrod E. Church ◽  
Davin Jagnandan ◽  
John D. Catravas ◽  
William C. Sessa ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
No Synthase ◽  
Endothelial No Synthase ◽  
Functional Relevance

Endostatin uncouples NO and Ca2+response to bradykinin through enhanced O2−· production in the intact coronary endothelium

2005 ◽  
Vol 288 (2) ◽  
pp. H686-H694 ◽  
Author(s):  
Andrew Y. Zhang ◽  
Eric G. Teggatz ◽  
Ai-Ping Zou ◽  
William B. Campbell ◽  
Pin-Lan Li
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
High Speed ◽  
Imaging Techniques ◽  
No Synthase ◽  
No Production ◽  
Intracellular Ca ◽  
Coronary Endothelial Cells ◽  
Coronary Endothelium ◽  
O2 Production

The present study tested the hypothesis that endostatin stimulates superoxide (O2−·) production through a ceramide-mediating signaling pathway and thereby results in an uncoupling of bradykinin (BK)-induced increases in intracellular Ca2+concentration ([Ca2+]i) from nitric oxide (NO) production in coronary endothelial cells. With the use of high-speed, wavelength-switching, fluorescence-imaging techniques, the [Ca2+]iand NO levels were simultaneously monitored in the intact endothelium of freshly isolated bovine coronary arteries. Under control conditions, BK was found to increase NO production and [Ca2+]iin parallel. When the arteries were pretreated with 100 nM human recombinant endostatin for 1 h, this BK-induced NO production was reduced by 89%, whereas [Ca2+]iwas unchanged. With the conversion rate of l-[3H]arginine to l-[3H]citrulline measured, endostatin had no effect on endothelial NO synthase (NOS) activity, but it stimulated ceramide by activation of sphingomyelinase (SMase), whereby O2−· production was enhanced in endothelial cells. O2−· scavenging by tiron and inhibition of NAD(P)H oxidase by apocynin markedly reversed the effect of endostatin on the NO response to BK. These results indicate that endostatin increases intracellular ceramide levels, which enhances O2−· production through activation of NAD(P)H oxidase. This ceramide-O2−· signaling pathway may contribute importantly to endostatin-induced endothelial dysfunction.

Membrane depolarization and NADPH oxidase activation in aortic endothelium during ischemia reflect altered mechanotransduction

2005 ◽  
Vol 288 (1) ◽  
pp. H336-H343 ◽  
Author(s):  
Ikuo Matsuzaki ◽  
Shampa Chatterjee ◽  
Kris DeBolt ◽  
Yefim Manevich ◽  
Qunwei Zhang ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Membrane Potential ◽  
Nadph Oxidase ◽  
Membrane Depolarization ◽  
Ros Generation ◽  
Similar Response ◽  
Aortic Endothelial Cells ◽  
Aortic Endothelium ◽  
Aortic Endothelial

We previously showed that “ischemia” (abrupt cessation of flow) leads to rapid membrane depolarization and increased generation of reactive oxygen species (ROS) in lung microvascular endothelial cells. This response is not associated with anoxia but, rather, reflects loss of normal shear stress. This study evaluated whether a similar response occurs in aortic endothelium. Plasma membrane potential and production of ROS were determined by fluorescence microscopy and cytochrome c reduction in flow-adapted rat or mouse aorta or monolayer cultures of rat aortic endothelial cells. Within 30 s after flow cessation, endothelial cells that had been flow adapted showed plasma membrane depolarization that was inhibited by pretreatment with cromakalim, an ATP-sensitive K+ (KATP) channel agonist. Flow cessation also led to ROS generation, which was inhibited by cromakalim and the flavoprotein inhibitor diphenyleneiodonium. Aortic endothelium from mice with “knockout” of the KATP channel (KIR6.2) showed a markedly attenuated change in membrane potential and ROS generation with flow cessation. In aortic endothelium from mice with knockout of NADPH oxidase (gp91phox), membrane depolarization was similar to that in wild-type mice but ROS generation was absent. Thus rat and mouse aortic endothelial cells respond to abrupt flow cessation by KATP channel-mediated membrane depolarization followed by NADPH oxidase-mediated ROS generation, possibly representing a cell-signaling response to altered mechanotransduction.

Intracellular and plasma membrane-initiated pathways involved in the [Ca2+]i elevations induced by iodothyronines (T3 and T2) in pituitary GH3 cells

2012 ◽  
Vol 302 (11) ◽  
pp. E1419-E1430 ◽  
Author(s):  
Adelaide Del Viscovo ◽  
Agnese Secondo ◽  
Alba Esposito ◽  
Fernando Goglia ◽  
Maria Moreno ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
No Synthase ◽  
Dominant Negative ◽  
Gh3 Cells ◽  
Phosphatidylinositol 3 Kinase ◽  
Atp Binding Site ◽  
Carbonyl Cyanide ◽  
Intracellular Ca ◽  
Endogenous Nitric Oxide ◽  
Phosphatidylinositol 3

The role of 3,5,3′-triiodo-l-thyronine (T3) and its metabolite 3,5-diiodo-l-thyronine (T2) in modulating the intracellular Ca2+ concentration ([Ca2+]i) and endogenous nitric oxide (NO) synthesis was evaluated in pituitary GH3 cells in the absence or presence of extracellular Ca2+. When applied in Ca2+-free solution, T2 and T3 increased [Ca2+]i, in a dose-dependent way, and NO levels. Inhibition of neuronal NO synthase by NG-nitro-l-arginine methyl ester and l- n5-(1-iminoethyl)ornithine hydrochloride significantly reduced the [Ca2+]i increase induced by T2 and T3. However, while depletion of inositol trisphosphate-dependent Ca2+ stores did not interfere with the T2- and T3-induced [Ca2+]i increases, the inhibition of phosphatidylinositol 3-kinase by LY-294002 and the dominant negative form of Akt mutated at the ATP binding site prevented these effects. Furthermore, the mitochondrial protonophore carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone prevented the increases in both [Ca2+]i and NO elicited by T2 or T3. Interestingly, rotenone blocked the early [Ca2+]i increases elicited by T2 and T3, while antimycin prevented only that elicited by T3. Inhibition of mitochondrial Na+/Ca2+ exchanger by CGP37157 significantly reduced the [Ca2+]i increases induced by T2 and T3. In the presence of extracellular calcium (1.2 mM), under carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, T2 and T3 increased both [Ca2+]i and intracellular Na+ concentration; nimodipine reduced the [Ca2+]i increases elicited by T2 and T3, but inhibition of NO synthase and blockade of the Na+/H+ pump by 5-( N-ethyl- N-isopropyl)amiloride prevented only that elicited by T3; and CB-DMB, bisindolylmaleimide, and LY-294002 (inhibitors of the Na+/Ca2+ exchanger, PKC, and phosphatidylinositol 3-kinase, respectively) failed to modify the T2- and T3-induced effects. Collectively, the present results suggest that T2 and T3 exert short-term nongenomic effects on intracellular calcium and NO by modulating plasma membrane and mitochondrial pathways that differ between these iodothyronines.

scholarly journals Superoxide Flux in Endothelial Cells via the Chloride Channel-3 Mediates Intracellular Signaling

2007 ◽  
Vol 18 (6) ◽  
pp. 2002-2012 ◽  
Author(s):  
Brian J. Hawkins ◽  
Muniswamy Madesh ◽  
C. J. Kirkpatrick ◽  
Aron B. Fisher
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Chloride Channel ◽  
Intracellular Signaling ◽  
Anion Channel ◽  
Transmembrane Flux ◽  
Cell Plasma ◽  
Intracellular Ca ◽  
Cellular Apoptosis ◽  
Extracellular Side

Reactive oxygen species (ROS) have been implicated in both cell signaling and pathology. A major source of ROS in endothelial cells is NADPH oxidase, which generates superoxide (O2.−) on the extracellular side of the plasma membrane but can result in intracellular signaling. To study possible transmembrane flux of O2.−, pulmonary microvascular endothelial cells were preloaded with the O2.−-sensitive fluorophore hydroethidine (HE). Application of an extracellular bolus of O2.−resulted in rapid and concentration-dependent transient HE oxidation that was followed by a progressive and nonreversible increase in nuclear HE fluorescence. These fluorescence changes were inhibited by superoxide dismutase (SOD), the anion channel blocker DIDS, and selective silencing of the chloride channel-3 (ClC-3) by treatment with siRNA. Extracellular O2.−triggered Ca2+release in turn triggered mitochondrial membrane potential alterations that were followed by mitochondrial O2.−production and cellular apoptosis. These “signaling” effects of O2.−were prevented by DIDS treatment, by depletion of intracellular Ca2+stores with thapsigargin and by chelation of intracellular Ca2+. This study demonstrates that O2.−flux across the endothelial cell plasma membrane occurs through ClC-3 channels and induces intracellular Ca2+release, which activates mitochondrial O2.−generation.

scholarly journals Endothelial pannexin 1 channels control inflammation by regulating intracellular calcium

2019 ◽  
Author(s):  
Yang Yang ◽  
Leon Delalio ◽  
Angela K Best ◽  
Edgar Macal ◽  
Jenna Milstein ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Endothelial Cells ◽  
Plasma Membrane ◽  
Intracellular Calcium ◽  
Tumor Necrosis ◽  
Purinergic Signaling ◽  
Flow Cytometric Analysis ◽  
Atp Release ◽  
Pannexin 1 ◽  
Intracellular Ca

In BriefInterleukine-1 beta (IL-1β) has been identified as a critical factor that contributes to the inflammatory response in cardiovascular disease (e.g., atherosclerosis). Pannexin 1 (Panx1) channel activity in endothelial cells regulates localized inflammatory cell recruitment. In response to prolonged tumor necrosis factor alpha (TNF) treatment, Yang et al. found that the Panx1 channel is targeted to the plasma membrane, where it facilitates an increase in intracellular calcium to control the production and release of cytokines including IL-1β.GRAPHICAL ABSTRACTAbstractThe proinflammatory cytokine IL-1β is a significant risk factor in cardiovascular disease that can be targeted to reduce major cardiovascular events. IL-1β expression and release are tightly controlled by changes in intracellular Ca2+. In addition, purinergic signaling through ATP release has also been reported to promote IL-1β production. Despite this, the mechanisms that control IL-1β synthesis and expression have not been identified. The pannexin 1 (Panx1) channel has canonically been implicated in ATP release, especially during inflammation. However, resolution of purinergic signaling occurs quickly due to blood flow and the presence of ectonucleotidases. We examined Panx1 in human endothelial cells following treatment with the pro-inflammatory cytokine tumor necrosis alpha (TNF). In response to long-term TNF treatment, we identified a dramatic increase in Panx1 protein expression at the plasma membrane. Analysis by whole transcriptome sequencing (RNA-seq), qPCR, and treatment with specific kinase inhibitors, revealed that TNF signaling induced NFκβ-associated Panx1 transcription. Genetic inhibition of Panx1 reduced the expression and secretion of IL-1β. We initially hypothesized that increased Panx1-mediated ATP release acted in a paracrine fashion to control cytokine expression. However, our data demonstrate that IL1-β expression was not altered after direct ATP stimulation, following degradation of ATP by apyrase, or after pharmacological blockade of P2 receptors. These data suggest that non-purinergic pathways, involving Panx1, control IL-1β production. Because Panx1 forms a large pore channel, we hypothesized it may act to passively diffuse Ca2+ into the cell upon opening to regulate IL-1β. High-throughput flow cytometric analysis demonstrated that TNF treatments lead to elevated intracellular Ca2+. Genetic or pharmacological inhibition of Panx1 reduced TNF-associated increases in intracellular Ca2+, and IL-1β transcription. Furthermore, we found that the Ca2+-sensitive NFκβ-p65 protein failed to localize to the nucleus after genetic or pharmacological block of Panx1. Taken together, our study provides the first evidence that intracellular Ca2+ regulation via the Panx1 channel induces a feed-forward effect on NFκβ to regulate IL-1β synthesis and release in endothelium during inflammation.

Calcium release from Synechocystis cells induced by depolarization of the plasma membrane: MscL as an outward Ca2+ channel

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1147-1153 ◽  
Author(s):  
Lyudmila V. Nazarenko ◽  
Igor M. Andreev ◽  
Alexander A. Lyukevich ◽  
Tatiana V. Pisareva ◽  
Dmitry A. Los
Keyword(s):  
Plasma Membrane ◽  
Calcium Release ◽  
Channel Blocker ◽  
Membrane Depolarization ◽  
Wild Type ◽  
Exact Function ◽  
Intracellular Ca ◽  
In The Wild ◽  
Mechanosensitive Ion Channel ◽  
Mutant Cells

Cells of the cyanobacterium Synechocystis sp. PCC 6803 are equipped with a mechanosensitive ion channel MscL that is located in their plasma membrane. However, the exact function of the channel in this freshwater cyanobacterium is unknown. This study shows that cells of Synechocystis are capable of releasing Ca2+ in response to depolarization of the plasma membrane by the K+ ionophore valinomycin in the presence of K+ or by tetraphenylphosphonium (TPP+). A fluorescent dye, diS-C3-(5), sensitive to membrane potential and the metallochromic Ca2+ indicator arsenazo III were used to follow the plasma membrane depolarization and the Ca2+ release, respectively. The Ca2+ release from wild-type cells was temperature-dependent and it was strongly inhibited by the Ca2+ channel blocker verapamil and by the mechanosensitive channel blocker amiloride. In MscL-deficient cells, Ca2+ release was about 50 % of that from the wild-type cells. The mutant cells had lost temperature sensitivity of Ca2+ release completely. However, verapamil and amiloride inhibited Ca2+ release from these cells in same manner as in the wild-type cells. This suggests the existence of additional Ca2+ transporters in Synechocystis, probably of a mechanosensitive nature. Evidence for the putative presence of intracellular Ca2+ stores in the cells was obtained by following the increase in fluorescence intensity of the Ca2+ indicator chlortetracycline. These results suggest that the MscL of Synechocystis might operate as a verapamil/amiloride-sensitive outward Ca2+ channel that is involved in the plasma-membrane depolarization-induced Ca2+ release from the cells under temperature stress conditions.

scholarly journals P-selectin must extend a sufficient length from the plasma membrane to mediate rolling of neutrophils.

1995 ◽  
Vol 131 (6) ◽  
pp. 1893-1902 ◽  
Author(s):  
K D Patel ◽  
M U Nollert ◽  
R P McEver
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Plasma Membrane ◽  
Cho Cells ◽  
Transmembrane Domain ◽  
Wild Type ◽  
Shear Forces ◽  
Lectin Domain ◽  
Egf Domain ◽  
Static Conditions

Under physiological shear stress, neutrophils roll on P-selectin on activated endothelial cells or platelets through interactions with P-selectin glycoprotein ligand-1 (PSGL-1). Both P-selectin and PSGL-1 are extended molecules. Human P-selectin contains an NH2-terminal lectin domain, an EGF domain, nine consensus repeats (CRs), a transmembrane domain, and a cytoplasmic tail. To determine whether the length of P-selectin affected its interactions with PSGL-1, we examined the adhesion of neutrophils to CHO cells expressing membrane-anchored P-selectin constructs in which various numbers of CRs were deleted. Under static conditions, neutrophils attached equivalently to wild-type P-selectin and to constructs containing from 2-6 CRs. Under shear stress, neutrophils attached equivalently to wild-type and 6 CR P-selectin and nearly as well to 5 CR P-selectin. However, fewer neutrophils attached to the 4 CR construct, and those that did attach rolled faster and were more readily detached by increasing shear stress. Flowing neutrophils failed to attach to the 3 CR and 2 CR constructs. Neutrophils attached and rolled more efficiently on 4 CR P-selectin expressed on glycosylation-defective Lec8 CHO cells, which have less glycocalyx. We conclude that P-selectin must project its lectin domain well above the membrane to mediate optimal attachment of neutrophils under shear forces. The length of P-selectin may: (a) facilitate interactions with PSGL-1 on flowing neutrophils, and (b) increase the intermembrane distance where specific bonds form, minimizing contacts between the glycocalyces that result in cell-cell repulsion.

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