Role of erythrocyte phosphatidylserine in sickle red cell–endothelial adhesion

Blood ◽  
2002 ◽  
Vol 99 (5) ◽  
pp. 1564-1571 ◽  
Author(s):  
B. N. Yamaja Setty ◽  
Surekha Kulkarni ◽  
Marie J. Stuart
Keyword(s):  
Annexin V ◽  
Inhibitory Effect ◽  
Vascular Pathology ◽  
Membrane Asymmetry ◽  
Adhesion Receptor ◽  
Sickle Erythrocyte ◽  
Erythrocyte Surface ◽  
Erythrocyte Adhesion ◽  
The Individual

Phosphatidlyserine (PS) exposure on the erythrocyte surface endows the cell with the propensity of adhering to vascular endothelium. Because individuals with sickle cell disease (SCD) manifest loss of erythrocyte membrane asymmetry with PS exposure, we have assessed the contribution of this marker to the process of sickle erythrocyte–microendothelial adhesion. Assays for plasma-induced adhesion were conducted on unactivated endothelium, in the absence of immobilized ligands, such that PS was compared to the erythrocyte adhesion receptor CD36. Blocking studies with erythrocytes pretreated with annexin V (to cloak PS) or anti-CD36 or both revealed an inhibitory effect on adhesion of 36% ± 10% and 23% ± 8% with blocking of both sites suggestive of an additive effect. We next evaluated 87 blood samples from patients with SCD and grouped them into 4 categories based on adhesion marker (CD36 and PS) levels. Results revealed a striking correlation between erythrocyte PS positivity and adhesion. Analyses of the individual patient data demonstrated a positive correlation between PS and adhesion (R = 0.52,P < .000 001), whereas none was noted between adhesion and CD36 (R = 0.2, P > .07). The effect of PS on adhesion appears to be related to the quantitative differences in erythrocyte markers in SCD, with PS the predominant marker when compared to CD36 both in the total erythrocyte population, and when the adherence-prone erythrocyte, the CD71+ stress reticulocyte, was evaluated. Our study signals the entrance of an important new contributor to the field of sickle erythrocyte–endothelial adhesion. The implications of erythrocyte PS exposure in relation to the vascular pathology of SCD need to be assessed.

Sphingosine-1 Phosphate (S1P) Is a Myeloma Survival Factor and Protects Myeloma Cells from Thalidomide-Induced Growth Inhibition by Counteracting Ceramide Activity.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3509-3509
Author(s):  
Xin Li ◽  
Angela Pennisi ◽  
Shmuel Yaccoby
Keyword(s):  
Drug Resistance ◽  
Growth Inhibition ◽  
Annexin V ◽  
Myeloma Cell ◽  
Inhibitory Effect ◽  
Tunel Staining ◽  
Serum Starvation ◽  
Myeloma Cells ◽  
Sphingosine 1 Phosphate

Abstract Sphingosine 1-phosphate (S1P) and ceramide are sphingolipid metabolites and their intracellular balance impacts fate of normal and cancer cells; whereas S1P stimulates tumor cell migration, survival, proliferation and drug resistance, ceramide acts as endogenous pro-apototic factor. The role of S1P/ceramide pathway in myeloma has not been reported. Recent study demonstrated that thalidomide’s antiangiogenic activity involves increased production of ceramide in microvessels (Yabu et al., Blood 2005). In this study we tested the effect of S1P and ceramide on myeloma growth and determined the protective role of S1P against the inhibitory effect of thalidomide on myeloma cells. S1P (0.1–10 μM) stimulated growth of several human myeloma cell lines in serum-free media in time and dose dependent manners, reaching maximum response (>25%, p<0.001) at approximately 5 μM. Annexin V/PI flow analysis and TUNEL staining for detection of apoptosis revealed reduced percent of apoptotic myeloma cells following S1P treatment. S1P also consistently and significantly protected primary CD138-selected myeloma cells (n=5) from serum starvation-induced apoptosis as shown by MTT assay (p<0.01) and annexin V/PI flow cytometry (p<0.05). In contrast, synthetic ceramide (3–10 μM) inhibited growth of myeloma cells, an effect that was completely counteracted by S1P. We have previously demonstrated that osteoclasts and megakaryocytes support primary myeloma cell survival. Autotaxin, a key exo-enzyme involved in extracellular production of S1P and lysophosphatidic acid (LPA), was consistently upregulated in primary myeloma cells by 11±3 folds over baseline levels after co-culture with osteoclasts (n=17, p<0.01) and by 4±1 folds after co-culture with megakaryocytes (n=5, p<0.04), as assessed by microarray and confirmed by qRT-PCR. Furthermore, in co-cultures the S1P receptors antagonist, FTY720, at concentrations that have no direct anti-tumor response (≤1 μM), inhibited the stimulatory effects of osteoclasts and megakaryocytes on survival of our BN-stroma dependent myeloma cell line by 30% to 50% (p<0.001) suggesting that S1P is an important microenvironmental factor in myelomatous bone. Since metabolic activation of thalidomide is required for its anti-tumor activity, thalidomide (10–100 μM) was incubated with active human microsomes while control non-metabolized thalidomide was similarly prepared using inactivated microsomes. Metabolized but not non-metabolized thalidomide effectively inhibited growth of myeloma cells by >40% (p<0.001). Addition of S1P (1 μM) completely abrogated the inhibitory effect of metabolized thalidomide in all tested doses. We conclude that S1P is a myeloma survival and growth factor and protects myeloma cells from thalidomide-induced growth inhibition, presumably through counteracting increased ceramide activity by thalidomide. Pharmacological modulation of enzymes involved in regulation of the ceramide to S1P ratio and blocking S1P activity could constitute novel therapeutic approaches for treating and overcoming drug resistance in myeloma.

The p55 TNF receptor mediates TNF inhibition of osteoblast differentiation independently of apoptosis

2005 ◽  
Vol 288 (5) ◽  
pp. E1011-E1018 ◽  
Author(s):  
Linda C. Gilbert ◽  
Janet Rubin ◽  
Mark S. Nanes
Keyword(s):  
Cell Viability ◽  
Caspase 3 ◽  
Annexin V ◽  
Inhibitory Effect ◽  
Tnf Receptor ◽  
Trypan Blue Exclusion ◽  
Total Dna ◽  
Factor Α ◽  
Tnf Inhibition

After menopause, increased tumor necrosis factor-α (TNF-α) stimulates bone resorption while inhibiting differentiation of new bone-forming osteoblasts (OB). TNF receptors, p55 and p75, signal similar intracellular pathways, but only p55 activates apoptosis. To evaluate the relationship between the TNF receptor mediating inhibition of OB differentiation and the role of apoptosis, marrow stromal cells (MSC) were cultured from mice deficient in either or both receptors. Cells grown in ascorbate and β-glycerophosphate produce alkaline phosphatase and osteocalcin and mineralize matrix. Treatment of wild-type or p55+/+/p75−/− MSC with murine TNF (binds p55 and p75) or human TNF (binds only p55) inhibited OB differentiation. TNF did not inhibit OB differentiation in p55−/− MSC. Expression of p75 modestly attenuated sensitivity to TNF. To determine the role of apoptosis, changes in total DNA, cell viability, caspase 3, and percentage of annexin V-positive cells were measured in MSC and preosteoblastic MC3T3 cells. TNF treatment that reduced differentiation by 50% did not decrease cell viability or increase apoptosis, as determined by alamar blue reduction, trypan blue exclusion, and percentage of annexin V-positive cells. TNF increased caspase 3 activity 1.5-fold in MC3T3 and insignificantly in MSC cells compared with >4-fold after 4 h actinomycin D. Treatment of MSC or MC3T3 cells with three caspase inhibitors failed to reverse the inhibitory effect of TNF on OB differentiation despite inhibition of caspase activity. These results suggest that the p55 receptor is essential, and p75 dispensable, for TNF inhibition of OB differentiation through a mechanism that does not require apoptosis.

Dynamic adhesion of eryptotic erythrocytes to immobilized platelets via platelet phosphatidylserine receptors

2014 ◽  
Vol 306 (3) ◽  
pp. C291-C297 ◽  
Author(s):  
Britta Walker ◽  
Syeda T. Towhid ◽  
Evi Schmid ◽  
Sascha M. Hoffmann ◽  
Majed Abed ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Annexin V ◽  
Vascular Occlusion ◽  
Adenosine Diphosphate ◽  
Flow Chamber ◽  
Adhesive Properties ◽  
Glucose Depletion ◽  
Phosphatidylserine Exposure ◽  
Erythrocyte Surface ◽  
Erythrocyte Adhesion

Glucose depletion of erythrocytes triggers suicidal erythrocyte death or eryptosis, which leads to cell membrane scrambling with phosphatidylserine exposure at the cell surface. Eryptotic erythrocytes adhere to endothelial cells by a mechanism involving phosphatidylserine at the erythrocyte surface and CXCL16 as well as CD36 at the endothelial cell membrane. Nothing has hitherto been known about an interaction between eryptotic erythrocytes and platelets, the decisive cells in primary hemostasis and major players in thrombotic vascular occlusion. The present study thus explored whether and how glucose-depleted erythrocytes adhere to platelets. To this end, adhesion of phosphatidylserine-exposing erythrocytes to platelets under flow conditions was examined in a flow chamber model at arterial shear rates. Platelets were immobilized on collagen and further stimulated with adenosine diphosphate (ADP, 10 μM) or thrombin (0.1 U/ml). As a result, a 48-h glucose depletion triggered phosphatidylserine translocation to the erythrocyte surface and augmented the adhesion of erythrocytes to immobilized platelets, an effect significantly increased upon platelet stimulation. Adherence of erythrocytes to platelets was blunted by coating of erythrocytic phosphatidylserine with annexin V or by neutralization of platelet phosphatidylserine receptors CXCL16 and CD36 with respective antibodies. In conclusion, glucose-depleted erythrocytes adhere to platelets. The adhesive properties of platelets are augmented by platelet activation. Erythrocyte adhesion to immobilized platelets requires phosphatidylserine at the erythrocyte surface and CXCL16 as well as CD36 expression on platelets. Thus platelet-mediated erythrocyte adhesion may foster thromboocclusive complications in diseases with stimulated phosphatidylserine exposure of erythrocytes.

scholarly journals Effect of Lactobacillus sp. isolates supernatant on Escherichia coli O157:H7 enhances the role of organic acids production as a factor for pathogen control

2015 ◽  
Vol 35 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Larissa B. Poppi ◽  
Javier D. Rivaldi ◽  
Thais S. Coutinho ◽  
Claudete S. Astolfi-Ferreira ◽  
Antonio J. Piantino Ferreira ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Lactic Acid ◽  
Foodborne Pathogens ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Antagonistic Effect ◽  
Pure Cultures ◽  
Pathogen Control ◽  
The Individual

Many attempts have been made to establish the control of foodborne pathogens through Lactobacillus isolates and their metabolism products with success being obtained in several situations. The aim of this study was to investigate the antagonistic effect of eight Lactobacillusisolates, including L. caseisubsp. pseudoplantarum,L. plantarum, L. reuteri and L. delbrueckii subsp. delbrueckii, on the pathogenic Escherichia colistrain O157:H7. The inhibitory effect of pure cultures and two pooled cultures supernatants of Lactobacillus on the growth of pathogenic bacteria was evaluated by the spot agar method and by monitoring turbidity. Antimicrobial activity was confirmed for L. reuteri and L. delbrueckii subsp. delbrueckii and for a pool of lactic acid bacteria. The neutralized supernatant of the pool exerted a higher antimicrobial activity than that of the individual strains. Furthermore, D-lactic acid and acetic acid were produced during growth of the Lactobacillus isolates studied.

School Success and School Engagement of Immigrant Children and Adolescents

2013 ◽  
Vol 18 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Frosso Motti-Stefanidi ◽  
Ann S. Masten
Keyword(s):  
Academic Achievement ◽  
Academic Success ◽  
Children And Adolescents ◽  
School Engagement ◽  
School Success ◽  
Immigrant Children ◽  
Integrative Model ◽  
High Stakes ◽  
The Individual

Academic achievement in immigrant children and adolescents is an indicator of current and future adaptive success. Since the future of immigrant youths is inextricably linked to that of the receiving society, the success of their trajectory through school becomes a high stakes issue both for the individual and society. The present article focuses on school success in immigrant children and adolescents, and the role of school engagement in accounting for individual and group differences in academic achievement from the perspective of a multilevel integrative model of immigrant youths’ adaptation ( Motti-Stefanidi, Berry, Chryssochoou, Sam, & Phinney, 2012 ). Drawing on this conceptual framework, school success is examined in developmental and acculturative context, taking into account multiple levels of analysis. Findings suggest that for both immigrant and nonimmigrant youths the relationship between school engagement and school success is bidirectional, each influencing over time the other. Evidence regarding potential moderating and mediating roles of school engagement for the academic success of immigrant youths also is evaluated.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Purification and Characterization of Lupus Anticoagulant Like Protein from Agkistrodon Halys Brevicaudus Venom

1996 ◽  
Vol 76 (06) ◽  
pp. 0993-0997
Author(s):  
Zhao-Yan Li ◽  
Xiao-Wei Wu ◽  
Tie-Fu Yu ◽  
Eric C-Y Lian
Keyword(s):  
Amino Acid ◽  
Lupus Anticoagulant ◽  
Inhibitory Effect ◽  
Clotting Factor ◽  
Acid Oxidase ◽  
Crude Venom ◽  
Amino Acid Oxidase ◽  
Sds Page ◽  
The Individual ◽  
Reducing Condition

SummaryBy means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)Q(Q/K). It was devoid of phospho-lipaseA, fibrino(geno)lytic, 5′-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell’s viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.

The Effects of Heparin and Annexin V on Fibrin Accretion after Injury in the Jugular Veins of Rabbits

1993 ◽  
Vol 69 (03) ◽  
pp. 227-230 ◽  
Author(s):  
J Van Ryn-McKenna ◽  
H Merk ◽  
T H Müller ◽  
M R Buchanan ◽  
W G Eisert
Keyword(s):  
Vessel Wall ◽  
Thrombin Generation ◽  
Antithrombin Iii ◽  
Specific Effect ◽  
Annexin V ◽  
Inhibitory Effect ◽  
Jugular Veins ◽  
Prothrombinase Complex ◽  
Wall Injury

SummaryWe compared the relative abilities of unfractionated heparin and annexin V to prevent fibrin accretion onto injured jugular veins in vivo. Heparin was used to accelerate the inhibition of thrombin by antithrombin III, and annexin V was used to inhibit the assembly of the prothrombinase complex on phospholipid surfaces, thereby blocking thrombin generation. Rabbit jugular veins were isolated in situ, a 2 cm segment was injured by perfusing it with air, and then blood flow was re-established. Five minutes later, each rabbit was injected with heparin (20 U/kg) or annexin V (0.3 mg/kg) and then with 125I-fibrinogen. The amount of 125I-fibrin accumulation onto each injured vessel wall segment was measured 4 h later. Each injured vessel was completely deendothelialized as a result of the air perfusion as demonstrated by electron microscopy. 125I-fibrin accretion onto the injured jugular veins was enhanced 2.4-fold as compared to the uninjured veins in sham-operated animals. Heparin treatment did not reduce fibrin accretion, whereas, annexin V treatment decreased fibrin accretion by 60%, p <0.05. This latter effect was achieved without sustained circulating anticoagulation. Additional experiments confirmed that the inhibitory effect of annexin V on fibrin accretion was associated with a surface specific effect, since more annexin V bound to the injured jugular vein segments as compared to the non-injured jugular veins. We conclude that, i) mild vessel wall injury (selective de-endothelialization) in veins results in a thrombogenic vessel wall; ii) the thrombogenecity of which is not inhibited by prophylactic doses of heparin; but iii) is inhibited by annexin V, which binds to injured vessel wall surface, and inhibits thrombin generation independently of antithrombin III.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

УКРАЇНОЗНАВЧИЙ ОСВІТНІЙ ЧИННИК В УМОВАХ СУЧАСНОЇ УКРАЇНСЬКОЇ МАСОВОЇ КУЛЬТУРИ

2019 ◽  
pp. 22-29
Author(s):  
Н. В. Фрадкіна
Keyword(s):  
Mass Culture ◽  
Personal Development ◽  
Negative Impact ◽  
Educational Process ◽  
Point Of View ◽  
Character Trait ◽  
Main Task ◽  
Leading Role ◽  
The Individual

The purpose and tasks of the work are to analyze the contemporary Ukrainian mass culture in terms of its value and humanistic components, as well as the importance of cultural studies and Ukrainian studies in educational disciplines for the formation of a holistic worldview of modern youth.Analysis of research and publications. Scientists repeatedly turned to the problems of the role of spirituality in the formation of society and its culture. This problem is highlighted in the publications by O. Losev, V. Lytvyn, D. Likhachev, S. Avierintsev, M. Zakovych, I. Stepanenko and E. Kostyshyn.Experts see the main negative impact of mass culture on the quality approach, which determines mass culture through the market, because mass culture, from our point of view, is everything that is sold and used in mass demand.One of the most interesting studies on this issue was the work by the representatives of Frankfurt School M. Horkheimer and T. Adorno «Dialectics of Enlightenment» (1947), devoted to a detailed analysis of mass culture. Propaganda at all socio-cultural levels in the form is similar in both totalitarian and democratic countries. It is connected, according to the authors, with the direction of European enlightenment. The tendency to unify people is a manifestation of the influence of mass culture, from cinema to pop. Mass culture is a phenomenon whose existence is associated with commerce (accumulation in any form – this is the main feature of education), in general, the fact that it exists in this form is related to the direction of the history of civilization.Modern mass culture, with its externally attractive and easily assimilated ideas and symbols, appealing to the trends of modern fashion, becomes a standard of prestigious consumption, does not require intense reflection, allows you to relax, distract, not teach, but entertains, preaches hedonism as the main spiritual value. And as a consequence, there are socio-cultural risks: an active rejection of other people, which leads to the formation of indifference; cruelty as a character trait; increase of violent and mercenary crime; increase in the number of alcohol and drug addicts; anti-patriotism; indifference to the values of the family and as a result of social orphanhood and prostitution.Conclusions, perspectives of research. Thus, we can conclude that modern Ukrainian education is predominantly formed by the values of mass culture. Namely, according to the «Dialectic» by Horkheimer and Adorno, «semi-enlightenment becomes an objective spirit» of our modern society.It is concluded that only high-quality education can create the opposite of the onset of mass culture and the destruction of spirituality in our society. It is proved that only by realizing the importance of cultivating disciplines in the educational process and the spiritual upbringing of the nation, through educational reforms, humanitarian knowledge will gradually return to student audiences.Formation of youth occurs under the influence of social environment, culture, education and self-education. The optimal combination of these factors determines both the process of socialization itself and how successful it will be. In this context, one can see the leading role of education and upbringing. It turns out that the main task of modern education is to spread its influence on the development of spiritual culture of the individual, which eventually becomes a solid foundation for the formation of the individual. Such a subject requires both philosophical and humanitarian approaches in further integrated interdisciplinary research, since the availability of such research will provide the theoretical foundation for truly modern educational and personal development.

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