Membrane perturbation by mastoparan 7 elicits a broad alteration in lipid composition of L1210 cells

Park, Heung Soon; Lee, Sang Yoon; Kim, Young Hwan; Kim, Jin Young; Lee, Soo Jae; Choi, Myung-Un

doi:10.1016/s1388-1981(00)00002-0

Cited by 17 publications

(10 citation statements)

References 38 publications

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“…MST7, synthesized by substituting alanine for the positively charged lysine in position 12, acts as a potent analog of MST in human rbcs and other cell systems [14,15]. Both MST and MST7 are known to activate ATP efflux of human rbcs [15].…”

Section: Introductionmentioning

confidence: 99%

Kinetics of extracellular ATP in mastoparan 7-activated human erythrocytes

Denis

Incicco

Espelt

et al. 2013

Biochimica et Biophysica Acta (BBA) - General Subjects

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SUMMARY Background The peptide mastoparan 7 (MST7) stimulated ATP release in human erythrocytes. We explored intra- and extracellular processes governing the time-dependent accumulation of extracellular ATP (i.e., ATPe kinetics). Methods Human erythrocytes were treated with MST7 in the presence or absence of two blockers of pannexin 1. ATPe concentration was monitored by luciferin-luciferase based real-time luminometry. Results Exposure of human erythrocytes to MST7 led to an acute increase in [ATPe], followed by a slower increase phase. ATPe kinetics reflected a strong activation of ATP efflux and a low rate of ATPe hydrolysis by ectoATPase activity. Enhancement of [ATPe] by MST7 required adhesion of erythrocytes to poly-D-lysin-coated coverslips, and correlated with a 31% increase of cAMP and 10% cell swelling. However, when MST7 was dissolved in a hyperosmotic medium to block cell swelling, ATPe accumulation was inhibited by 49%. Erythrocytes pre-exposure to 10 μM of either carbenoxolone or probenecid, two blockers of pannexin 1, exhibited a partial reduction of ATP efflux. Erythrocytes from pannexin 1 knockout mice exhibited similar ATPe kinetics as those of wild type mice erythrocytes exposed to pannexin 1 blockers. Conclusions MST7 induced release of ATP required either cell adhesion or strong activation of cAMP synthesis. Part of this release required cell swelling. Kinetic analysis and a data driven model suggested that ATP efflux is mediated by two ATP conduits displaying different kinetics, with one conduit being fully blocked by pannexin 1 blockers. General Significance Kinetic analysis of extracellular ATP accumulation from human erythrocytes and potential effects on microcirculation.

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Section: Introductionmentioning

confidence: 99%

Kinetics of extracellular ATP in mastoparan 7-activated human erythrocytes

Denis

Incicco

Espelt

et al. 2013

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…At the same time, they serve as enhancers of the lightscattering response (23,24). In addition, modifications of the solvent system proposed by Becart et al (25) with ammonium hydroxide in the mobile phase are widely used (26)(27)(28).…”

Section: Resultsmentioning

confidence: 99%

Light‐scattering detection of phospholipids resolved by HPLC

Descalzo

Insani

Pensel

2003

Lipids

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An improved method for the analysis of phospholipids by normal-phase HPLC is described. Addition of methanol and acetonitrile to a gradient based on 2-propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids (PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration curves were linear within the range of 5-40 microg with detection limits below 1 microg for PE and PC, and CV ranged from 0.6 to 9.6%. PL present in surfactant homogenates were separated by a solid-phase extraction (SPE) procedure before HPLC analysis. This methodology gave a recovery of 95% and combined SPE-HPLC and quantification of biological PL within a 30-min run. The use of ELSD detection of the eluted compounds was precise, linear, and sensitive.

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“…Cells grown on polystyrene plates were treated with 50 μM Mas-7 (Sigma-Aldrich), a G protein activator and a highly potent analog of mastoparan [37, 38] for 30 min at 37 °C in PBS containing 1μM 59 Fe-Ft and then washed three times with ice-cold PBS to remove any loosely bound radioactivity. Exofacially bound Ft was removed by a brief acid wash (0.15 M NaCl, pH 3.0 for 30 s, on ice) and cellular radioactivity was quantified in the gamma counter.…”

Section: Methodsmentioning

confidence: 99%

Receptor-mediated uptake of ferritin-bound iron by human intestinal Caco-2 cells

Kalgaonkar

Lönnerdal

2009

The Journal of Nutritional Biochemistry

100

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Ferritin (Ft) is a large iron-binding protein (~450 kDa) that is found in plant and animal cells and can sequester up to 4,500 iron (Fe) atoms per Ft molecule. Our previous studies on intestinal Caco-2 cells have shown that dietary factors affect the uptake of Fe from ferritin in a manner different from that of Fe from FeSO 4 , suggesting a different mechanism for cellular uptake. The objective of this study was to determine the mechanism for Ft-Fe uptake using Caco-2 cells. Binding of 59 Fe-labeled Ft at 4° C showed saturable kinetics and Scatchard analysis resulted in a K D of 1.6 μM, strongly indicating a receptor-mediated process. Competitive binding studies with excess unlabelled Ft significantly reduced binding and uptake studies at 37° C showed saturation after 4 h. Enhancing and blocking endocytosis using Mas-7 (a G-protein activator) and hypertonic medium (0.5 M sucrose), respectively, demonstrated that Ft-Fe uptake by Mas-7 treated cells was 140% of control cells, whereas sucrose treatment resulted in a statistically significant reduction in Ft-Fe uptake by 70% as compared to controls. Inhibition of macropinocytosis with 5-(N,N-dimethyl)-amiloride (Na + /H + antiport blocker) resulted in a decrease (by ~20%) in Ft-Fe uptake at high concentrations of Ft, suggesting that enterocytes can use more than one Ft-uptake mechanism in a concentration dependent manner. These results suggest that Ft uptake by enterocytes is carried out via endocytosis when Ft levels are within a physiological range, whereas Ft at higher concentrations may be absorbed using the additional mechanism of macropinocytosis.

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Membrane perturbation by mastoparan 7 elicits a broad alteration in lipid composition of L1210 cells

Cited by 17 publications

References 38 publications

Kinetics of extracellular ATP in mastoparan 7-activated human erythrocytes

Kinetics of extracellular ATP in mastoparan 7-activated human erythrocytes

Light‐scattering detection of phospholipids resolved by HPLC

Receptor-mediated uptake of ferritin-bound iron by human intestinal Caco-2 cells

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