Induction of ATP Release, PPIX Transport, and Cholesterol Uptake by Human Red Blood Cells Using a New Family of TSPO Ligands

Two main isoforms of the Translocator Protein (TSPO) have been identified. TSPO1 is ubiquitous and is mainly present at the outer mitochondrial membrane of most eukaryotic cells, whereas, TSPO2 is specific to the erythroid lineage, located at the plasma membrane, the nucleus, and the endoplasmic reticulum. The design of specific tools is necessary to determine the molecular associations and functions of TSPO, which remain controversial nowadays. We recently demonstrated that TSPO2 is involved in a supramolecular complex of the erythrocyte membrane, where micromolar doses of the classical TSPO ligands induce ATP release and zinc protoporphyrin (ZnPPIX) transport. In this work, three newly-designed ligands (NCS1016, NCS1018, and NCS1026) were assessed for their ability to modulate the functions of various erythrocyte’s and compare them to the TSPO classical ligands. The three new ligands were effective in reducing intraerythrocytic Plasmodium growth, without compromising erythrocyte survival. While NCS1016 and NCS1018 were the most effective ligands in delaying sorbitol-induced hemolysis, NCS1016 induced the highest uptake of ZnPPIX and NCS1026 was the only ligand inhibiting the cholesterol uptake. Differential effects of ligands are probably due, not only, to ligand features, but also to the dynamic interaction of TSPO with various partners at the cell membrane. Further studies are necessary to fully understand the mechanisms of the TSPO’s complex activation.

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Inhibition of Rho Kinase by Y27632 Increases Low Oxygen Tension‐Induced ATP Release from Human Red Blood Cells (RBCs)

The FASEB Journal ◽

10.1096/fasebj.24.1_supplement.974.3 ◽

2010 ◽

Vol 24 (S1) ◽

Author(s):

Kelly Thuet ◽

Elizabeth Bowles ◽

Meera Sridharan ◽

Shaquria Adderley ◽

Randy Sprague ◽

...

Keyword(s):

Red Blood Cells ◽

Oxygen Tension ◽

Blood Cells ◽

Atp Release ◽

Rho Kinase ◽

Low Oxygen ◽

Human Red Blood Cells ◽

Low Oxygen Tension

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ATP Release from Red Blood Cells Is Regulated by a Negative Feedback Pathway where ADP Acts on P2Y13 Receptors.

Blood ◽

10.1182/blood.v104.11.1576.1576 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1576-1576

Author(s):

Martin L. Olsson ◽

Lingwei Wang ◽

Goran Olivecrona ◽

Matthias Gotberg ◽

Stefan Amisten ◽

...

Keyword(s):

Red Blood Cells ◽

Negative Feedback ◽

Blood Cells ◽

Atp Release ◽

Pig Model ◽

Coronary Vein ◽

Human Red Blood Cells ◽

Adp Receptor ◽

Tissue Circulation ◽

Feedback Pathway

Abstract Background: Red blood cells regulate tissue circulation and O2 delivery by releasing the vasodilator adenosine triphosphate (ATP) in response to hypoxia. When released extracellularly, ATP is rapidly degraded to adenosine diphosphate (ADP) in the circulation by ectonucleotidases. ATP and ADP activate subtypes of the large P2 receptor family (15 subtypes). Here we show that ADP acting on P2Y13 receptors on red blood cells serves as a negative feedback pathway for the inhibition of ATP release. Methods: mRNA was quantified with real-time PCR. Western blot was used to detect P2 receptors with available antibodies. cAMP levels were determined with an enzyme immunoassay. ATP release was measured in incubated red blood cells using microdialysis and a luciferase assay. In a pig model, catheters were inserted through the carotid artery to place a catheter in the left coronary artery, and through the jugular vein to place a microdialysis probe in the coronary vein. 2-MeSADP was injected in the artery and ATP levels were measured in the coronary vein. Results: mRNA of the ADP receptor P2Y13 was highly expressed in human red blood cells and reticulocytes, whilst other ADP receptors were not (Fig.1). Figure Figure The stable ADP analogue 2-MeSADP decreased ATP release from red blood cells by inhibition of cAMP. The P2Y12 and P2Y13 receptor antagonist AR-C67085 (30 mM), but not the P2Y1 blocker MRS2179, inhibited the effects of 2-MeSADP. At doses where AR-C67085 only blocks P2Y12 (100 nM), it had no effect. AR-C67085 and the nucleotidase apyrase increased cAMP per se, indicating a constant cAMP inhibitory effect of endogenous extracellular ADP. 2-MeSADP reduced plasma ATP concentrations in an in vivo pig model. Furthermore, a missense polymorphism in the coding region of P2Y13 has been found that is in total disequilibrium with 5 polymorphisms in P2Y12 (the important ADP receptor in platelets) forming a haplotype that could contribute to vascular disease. Conclusion: Our results show that P2Y13 is selectively expressed in human red blood cells. The ATP degradation product ADP inhibited ATP release by acting on this receptor. This negative feedback system could be important in the control of plasma ATP levels and tissue circulation. Because blood consists of approximately 40% red blood cells, containing a 1000-fold higher ATP concentration than plasma (mM vs. uM), even a minor release of ATP from the high intracellular concentrations could have major circulatory effects. A negative system may therefore be of great physiological importance to mitigate ATP release. In addition, this finding could be of interest for efforts to preserve intracellular ATP in red blood cells during storage.

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Deformation-induced ATP release from red blood cells requires CFTR activity

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.275.5.h1726 ◽

1998 ◽

Vol 275 (5) ◽

pp. H1726-H1732 ◽

Cited By ~ 94

Author(s):

Randy S. Sprague ◽

Mary L. Ellsworth ◽

Alan H. Stephenson ◽

Mary E. Kleinhenz ◽

Andrew J. Lonigro

Keyword(s):

Cystic Fibrosis ◽

Red Blood Cells ◽

Blood Cells ◽

Atp Release ◽

Chronic Obstructive Lung Disease ◽

Mechanical Deformation ◽

Chronic Obstructive ◽

Healthy Humans ◽

Human Red Blood Cells ◽

Human Rbcs

Recently, it was reported that rabbit and human red blood cells (RBCs) release ATP in response to mechanical deformation. Here we investigate the hypothesis that the activity of the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP binding cassette, is required for deformation-induced ATP release from RBCs. Incubation of rabbit RBCs with either of two inhibitors of CFTR activity, glibenclamide (10 μM) or niflumic acid (20 μM), resulted in inhibition of deformation-induced ATP release. To demonstrate the contribution of CFTR to deformation-induced ATP release from human RBCs, cells from healthy humans, patients with cystic fibrosis (CF), or patients with chronic obstructive lung disease (COPD) unrelated to CF were studied. RBCs of healthy humans and COPD patients released ATP in response to mechanical deformation. In contrast, deformation of RBCs from patients with CF did not result in ATP release. We conclude that deformation-induced ATP release from rabbit and human RBCs requires CFTR activity, suggesting a previously unrecognized role for CFTR in the regulation of vascular resistance.

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TSPO as a target for glioblastoma therapeutics

Biochemical Society Transactions ◽

10.1042/bst20150015 ◽

2015 ◽

Vol 43 (4) ◽

pp. 531-536 ◽

Cited By ~ 16

Author(s):

Eryn L. Werry ◽

Melissa L. Barron ◽

Michael Kassiou

Keyword(s):

Glioblastoma Multiforme ◽

Clinical Outcome ◽

Diagnostic Imaging ◽

Mitochondrial Membrane ◽

Recent Progress ◽

Transmembrane Protein ◽

Translocator Protein ◽

Outer Mitochondrial Membrane ◽

Cancer Treatments ◽

Anti Cancer

The translocator protein (TSPO) is an 18-kDa five-transmembrane protein, which is primarily found in the outer mitochondrial membrane. Levels of this protein are up-regulated in the most aggressive and common glioma, glioblastoma multiforme (GM). Levels of TSPO also correlate with GM clinical outcome, suggesting that TSPO may be a novel GM diagnostic imaging agent. Therapeutically, targeting the TSPO may provide a mechanism to abrogate the apoptotic-resistant, invasive and aggressive nature of GM and may also provide a way of targeting other anti-cancer treatments to GM sites. This review highlights recent progress in research on TSPO-based diagnostic imaging and therapeutics for GM.

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Bioluminescent Monitoring of ATP Release from Human Red Blood Cells Treated with Nonionic Detergent

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm.1988.26.10.599 ◽

1988 ◽

Vol 26 (10) ◽

Author(s):

Tamás Köszegi ◽

Miklós Kellermayer ◽

Ferenc Kövecs ◽

Kázmér Jobst

Keyword(s):

Red Blood Cells ◽

Blood Cells ◽

Atp Release ◽

Human Red Blood Cells ◽

Nonionic Detergent ◽

Bioluminescent Monitoring

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Fluorescent Thienothiophene-Containing Squaraine Dyes and Threaded Supramolecular Complexes with Tunable Wavelengths between 600–800 nm

Molecules ◽

10.3390/molecules23092229 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2229 ◽

Cited By ~ 5

Author(s):

Wenqi Liu ◽

Hannah McGarraugh ◽

Bradley Smith

Keyword(s):

Near Infrared ◽

Fluorescence Emission ◽

Supramolecular Complex ◽

Spectral Studies ◽

Practical Applications ◽

Squaraine Dyes ◽

Guided Surgery ◽

New Family ◽

Fluorescence Guided Surgery ◽

Purification Methods

A new family of fluorescent thiophene and thienothiophene-containing squaraine dyes is described with tunable wavelengths that cover the absorption/emission range of 600–800 nm. The deep-red and near-infrared fluorescent compounds were easily prepared by simple synthesis and purification methods. Spectral studies showed that each squaraine was rapidly encapsulated by a tetralactam macrocycle, with nanomolar affinity in water, to produce a threaded supramolecular complex with high chemical stability, increased fluorescence quantum yield, and decreased fluorescence quenching upon dye self-aggregation. Energy transfer within the supramolecular complex permitted multiplex emission. That is, two separate dyes with fluorescence emission bands that match the popular Cy5 and Cy7 channels, could be simultaneously excited with a beam of 375 nm light. A broad range of practical applications is envisioned in healthcare diagnostics, microscopy, molecular imaging, and fluorescence-guided surgery.

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New classes of monohedral spherical tilings by non-convex spherical hexagons and non-convex spherical Pentagons with GeoGebra

10.29007/qk2k ◽

2019 ◽

Author(s):

Ana Maria D'Azevedo Breda ◽

José Manuel Dos Santos Dos Santos

Keyword(s):

Dynamic Interaction ◽

Local Action ◽

Construction Process ◽

New Class ◽

New Family ◽

The Family

In previous works we have ilustrate a procedure to obtain spherical tiling with GeoGebra. We have found new classes of monohedral spherical tiling by four spherical pentagons, and new class of dihedral spherical tiling by twelve spherical pentagons. One again, we would make use of GeoGebra to show how we can do generate new classes of monohedral non-convex hexagonal spherical tilings, H(C,τ), changing the side gluing rules of the regular spherical octahedral tiling, by local action of particular subgroups of spherical isometries.In relation to one of the new classes, by hexagonal tiles, we describe some of its properties. We also show the existence of a a new family of monohedral pentagonal tiling which arises as a degenarated case associated to the family H(C ,0) . All these classes of spherical tilings have emerged as a result of an interactive construction process, only possible by the use of newly produced GeoGebra tools and the dynamic interaction capabilities of this software.

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