Inhibition of platelet aggregation by acyl-CoA thioesters

Lin, Chu Yuan; Lubin, Bertram H.; Smith, Stuart

doi:10.1016/0304-4165(76)90107-0

Cited by 8 publications

(6 citation statements)

References 20 publications

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“…One of the unexpected findings was the presence of the fatty acid acyl-CoA molecule in the 12-LOX tetramer that co-purified with our enzyme from Expi293 cells. Fatty acid acyl-CoA derivatives have long been known to inhibit platelet aggregation 48,49 in a chain, length, and saturation-dependent manner. Specifically, the medium-chain acyl-CoA (palmitoyl, stearoyl, oleoyl and linoleoyl) inhibit lipoxygenase activity in platelets at concentrations ranging from 10 to 50 μ M 50 .…”

Section: Discussionmentioning

confidence: 99%

Cryo-EM structures of human arachidonate 12S-Lipoxygenase (12-LOX) bound to endogenous and exogenous inhibitors

Mobbs

Black

Tran

et al. 2023

Preprint

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Human 12-lipoxygenase (12-LOX) is an enzyme involved in platelet activation and is a promising target for antiplatelet therapies. Despite the clinical importance of 12-LOX, the exact mechanisms of how it affects platelet activation are unclear, and the lack of structural information has limited drug discovery efforts. In this study, we used single-particle cryo-electron microscopy to determine the high-resolution structures (1.7 Å- 2.8 Å) of human 12-LOX for the first time. Our results showed that 12-LOX can exist in multiple oligomeric states, from monomer to hexamer, which may impact its catalytic activity and membrane association. We also identified different conformations within a 12-LOX dimer, likely representing different time points in its catalytic cycle. Furthermore, we were able to identify small molecules bound to the 12-LOX structures. The active site of the 12-LOX tetramer is occupied by an endogenous 12-LOX inhibitor, a long-chain acyl-Coenzyme A. Additionally, we found that the 12-LOX hexamer can simultaneously bind to arachidonic acid and ML355, a selective 12-LOX inhibitor that has passed a phase I clinical trial for treating heparin-induced thrombocytopenia and has received fast-track designation by the FDA. Overall, our findings provide novel insights into the assembly of 12-LOX oligomers, its catalytic mechanism, and small molecule binding, paving the way for further drug development targeting the 12-LOX enzyme.

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Section: Discussionmentioning

confidence: 99%

Cryo-EM structures of human arachidonate 12S-Lipoxygenase (12-LOX) bound to endogenous and exogenous inhibitors

Mobbs

Black

Tran

et al. 2023

Preprint

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“…Both P2Y 1 and P2Y 12 are necessary for full‐scale ADP‐induced platelet aggregation [33,34]. Other derivatives of ADP, coenzyme A and acetyl‐coenzyme A, also inhibit ADP‐induced platelet aggregation [35], and inhibit both P2Y 1 and P2Y 12 , albeit with micromolar activities [36], leading to the proposal that agents that act at both of these receptors may provide more protection against the effects of ADP than agents acting at only one of these receptors [36]. Synergism from inhibition of both platelet ADP receptors was previously suggested by the combined use of antagonists with individual selectivity for either P2Y 1 or P2Y 12 : MRS2179 or A3P5P for P2Y 1 , and AR‐C69931MX for P2Y 12 [12,13].…”

Section: Discussionmentioning

confidence: 99%

Modified diadenosine tetraphosphates with dual specificity for P2Y1 and P2Y12 are potent antagonists of ADP‐induced platelet activation

Chang

Yanachkov

Dix

et al. 2012

Journal of Thrombosis and Haemostasis

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Summary Background Diadenosine 5′,5‴-P1,P4-tetraphosphate (Ap4A), a natural compound stored in platelet dense granules, inhibits ADP-induced platelet aggregation. Ap4A inhibits the platelet ADP receptors P2Y1 and P2Y12, is a partial agonist of P2Y12, and is a full agonist of the platelet ATP-gated ion channel P2X1. Modification of the Ap4A tetraphosphate backbone enhances inhibition of ADP-induced platelet aggregation. However, the effects of these Ap4A analogs on human platelet P2Y1, P2Y12 and P2X1 are unclear. Objective To determine the agonist and antagonist activities of diadenosine tetraphosphate analogs towards P2Y1, P2Y12, and P2X1. Methods We synthesized the following Ap4A analogs: P1,P4-dithiotetraphosphate; P2,P3-chloromethylenetetraphosphate; P1-thio-P2,P3-chloromethylenetetraphosphate; and P1,P4-dithio-P2,P3-chloromethylenetetraphosphate. We then measured the effects of these analogs on: (i) ADP-induced platelet aggregation; (ii) P2Y1-mediated changes in cytosolic Ca2+; (iii) P2Y12-mediated changes in vasodilator-stimulated phosphoprotein phosphorylation; and (iv) P2X1-mediated entry of extracellular Ca2+. Results Ap4A analogs with modifications in the phosphate backbone inhibited both P2Y1 and P2Y12, and showed no agonist activity towards these receptors. The dithio modification increased inhibition of P2Y1, P2Y12, and platelet aggregation, whereas the chloromethylene modification increased inhibition of P2Y12 and platelet aggregation, but decreased P2Y1 inhibition. Combining the dithio and chloromethylene modifications increased P2Y1 and P2Y12 inhibition. As compared with Ap4A, each modification decreased agonist activity towards P2X1, and the dual modification completely eliminated P2X1 agonist activity. Conclusions As compared with Ap4A, tetraphosphate backbone analogs of Ap4A have diminished activity towards P2X1 but inhibit both P2Y1 and P2Y12 and, with greater potency, inhibit ADP-induced platelet aggregation. Thus, diadenosine tetraphosphate analogs with dual receptor selectivity may have potential as antiplatelet drugs.

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“…Barton (1975) found that very low concentrations of Brij 58 (5 X 10"7 M) had no effect on shape change or primary ADPinduced platelet aggregation although the release reaction and secondary phase of aggregation was inhibited. Lin et al (1976) found that deoxycolate (2 X 10'4 M) had no effect on ADP-induced aggregation of human PRP. An examination of the effect of a wider concentration range of these and other detergents on platelet behaviour might help to clarify the role of hydrophobic interactions in initiating platelet responses or in interfering with platelet activation by various agonists.…”

Section: Discussionmentioning

confidence: 91%

The Effect of Small Organic Anions on Aggregation and Shape Change of Rabbit Platelets

Anderson

Foulks

1978

Thromb Haemost

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SummarySufficient concentrations of small organic anions inhibited ADP- or 5-HT-induced shape change and aggregation in rabbit PRP diluted with isotonic salt solutions. Both effects were concentration-dependent and varied with the size of the hydrocarbon chain. Carboxylate and sulfonate anions of corresponding size produced a similar degree of interference with aggregation but carboxylates were somewhat more effective than sulfonates in impairing shape change. The inhibitory effect of these anions was not potentiated by a phosphodiesterase inhibitor and therefore was not attributable to adenylate cyclase activation.The inhibition of shape change by both series of anions was enhanced at acid pH, an effect which was greater with carboxylates than with alkyl sulfonates. The pH dependence of shape change on the alkaline side of the optimum range was unaffected by either type of anion. These results show that organic anions exert their inhibitory effects on platelets at least in part at the external platelet surface, and that their effects can be influenced by the degree of dissociations of protonatable membrane groups. Hence, surface negative charge and hydrophobic interactions both play an important role in platelet functional responses and their modification by organic anions. The inhibition of aggregation by these anions was opposed by the addition of calcium. Kinetic analysis indicated that both activation of aggregation by Ca++ and inhibition of aggregation by organic anions involved more than one site or mechanism of action. The more sensitive inhibitory effect was surmounted by increased Ca++ concentrations without apparent alteration in the affinity of Ca++ binding sites and competitive antagonism was evident only at high concentrations of organic anions. A simple model to account for these effects is proposed.

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Inhibition of platelet aggregation by acyl-CoA thioesters

Cited by 8 publications

References 20 publications

Cryo-EM structures of human arachidonate 12S-Lipoxygenase (12-LOX) bound to endogenous and exogenous inhibitors

Cryo-EM structures of human arachidonate 12S-Lipoxygenase (12-LOX) bound to endogenous and exogenous inhibitors

Modified diadenosine tetraphosphates with dual specificity for P2Y1 and P2Y12 are potent antagonists of ADP‐induced platelet activation

The Effect of Small Organic Anions on Aggregation and Shape Change of Rabbit Platelets

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