Development of Platelet Inhibition by cAMP during Megakaryocytopoiesis

Dekker, Els den; Gorter, Gertie; Heemskerk, Johan W. M.; Akkerman, Jan-Willem Ν.

doi:10.1074/jbc.m111390200

Cited by 27 publications

(26 citation statements)

References 46 publications

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“…Variations in growth factor stimulation alter protein expression, illustrating the high responsiveness of megakaryocytes to cytokines. 20 We speculated that these cells might be equally responsive to adipokines and addressed this question in megakaryocytic CHRF-288-11 cells [20][21][22] and confirmed key observations in megakaryocytes. Results show that specific adipokines induce insulin resistance in these cells.…”

Section: Introductionsupporting

confidence: 52%

“…Megakaryocytic CHRF-288-11 cells have many properties in common with mature primary megakaryocytes, including receptors for thrombin, the presence of α-and d-granules and phospholipase C, which is an important step in receptor signaling to Ca 2+ . 21,40 They also respond to thrombin with Ca 2+ mobilization, 22 which is suppressed by high cAMP, 20 and express G i α2. 23 The present data show that CHRF-288-11 cells and primary megakaryocytes also respond to insulin with a decrease in Ca 2+ mobilization.…”

Section: Discussionmentioning

confidence: 99%

“…18,19 Apart from changing platelet functions through direct interference, adipokines may alter the properties of platelets during their synthesis from megakaryocytes. 20 Megakaryocytes develop from hematopoietic stem cells in the bone marrow. Their maturation is under the control of thrombopoietin, stem cell factor and other cytokines, which determine cell size, ploidy and protein expression.…”

Section: Introductionmentioning

confidence: 99%

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Induction of insulin resistance by the adipokines resistin, leptin, plasminogen activator inhibitor-1 and retinol binding protein 4 in human megakaryocytes

Gerrits¹,

Gitz²,

Koekman³

et al. 2012

Haematologica

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The online version of this article has a Supplementary Appendix. BackgroundIn normal platelets, insulin inhibits agonist-induced Ca 2+ mobilization by raising cyclic AMP. Platelet from patients with type 2 diabetes are resistant to insulin and show increased Ca 2+ mobilization, aggregation and procoagulant activity. We searched for the cause of this insulin resistance. Design and MethodsPlatelets, the megakaryocytic cell line CHRF-288-11 and primary megakaryocytes were incubated with adipokines and with plasma from individuals with a disturbed adipokine profile. Thrombininduced Ca 2+ mobilization and signaling through the insulin receptor and insulin receptor substrate 1 were measured. Abnormalities induced by adipokines were compared with abnormalities found in platelets from patients with type 2 diabetes. ResultsResistin, leptin, plasminogen activator inhibitor-1 and retinol binding protein 4 left platelets unchanged but induced insulin resistance in CHRF-288-11 cells. Interleukin-6, tumor necrosis factor-α and visfatin had no effect. These results were confirmed in primary megakaryocytes. Contact with adipokines for 2 hours disturbed insulin receptor substrate 1 Ser 307 -phosphorylation, while contact for 72 hours caused insulin receptor substrate 1 degradation. Plasma with a disturbed adipokine profile also made CHRF-288-11 cells insulin-resistant. Platelets from patients with type 2 diabetes showed decreased insulin receptor substrate 1 expression. ConclusionsAdipokines resistin, leptin, plasminogen activator-1 and retinol binding protein 4 disturb insulin receptor substrate 1 activity and expression in megakaryocytes. This might be a cause of the insulin resistance observed in platelets from patients with type 2 diabetes.Key words: adipokines, insulin, insulin resistance, megakaryocytes, platelets, obesity, type 2 diabetes.Citation: Gerrits AJ, Gitz E, Koekman CA, Visseren FL, van Haeften TW, and Haematologica 2012;97(08):1149-1157. doi:10.3324/haematol.2011

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Section: Introductionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Induction of insulin resistance by the adipokines resistin, leptin, plasminogen activator inhibitor-1 and retinol binding protein 4 in human megakaryocytes

Gerrits¹,

Gitz²,

Koekman³

et al. 2012

Haematologica

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“…2,3 Inhibition of the P2y 12 receptor reduces collagen-induced adhesion, aggregation and thrombin generation. 3,4 Subjects with a P2y 12 deficiency have a bleeding tendency 3,5 and individuals with an increased P2y 12 receptor copy number have platelets with an increased responsiveness to agonists, and these subjects experience peripheral arterial thrombosis. 6 The CAPRIE trial shows that long-term administration of the P2y 12 antagonist clopidogrel is more effective than aspirin in reducing the combined risk of ischemic stroke, myocardial infarction, or vascular death in subjects with a prothrombotic condition such as diabetes mellitus type 2 (DM2).…”

mentioning

confidence: 99%

Platelet Inhibition by Insulin Is Absent in Type 2 Diabetes Mellitus

Ferreira

Mocking

Feijge

et al. 2006

ATVB

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Objective-ADP-induced P2y 12 signaling is crucial for formation and stabilization of an arterial thrombus. We demonstrated recently in platelets from healthy subjects that insulin interferes with Ca 2ϩ increases induced by ADP-P2y 1 contact through blockade of the G-protein G i , and thereby with P2y 12 -mediated suppression of cAMP. Methods and Results-Here we show in patients with type 2 diabetes mellitus (DM2) that platelets have lost responsiveness to insulin leading to increased adhesion, aggregation, and procoagulant activity on contact with collagen. Using Ser 473 phosphorylation of protein kinase B as output for insulin signaling, a 2-fold increase is found in insulin-stimulated normal platelets, but in DM platelets there is no significant response. In addition, DM2 platelets show increased P2y 12 -mediated suppression of cAMP and decreased P2y 12 inhibition by the receptor antagonist AR-C69931MX. Key Words: P2y 12 receptor Ⅲ Ca 2ϩ regulation Ⅲ clopidogrel Ⅲ protein kinase B/Akt Ⅲ IRS-1 P latelet activation leads to release of components that initiate formation of a thrombus and start inflammatory responses that contribute to atherosclerosis. 1 Signaling through the P2y 12 receptor is crucial for formation and stabilization of a thrombus. 2,3 Inhibition of the P2y 12 receptor reduces collagen-induced adhesion, aggregation and thrombin generation. 3,4 Subjects with a P2y 12 deficiency have a bleeding tendency 3,5 and individuals with an increased P2y 12 receptor copy number have platelets with an increased responsiveness to agonists, and these subjects experience peripheral arterial thrombosis. 6 The CAPRIE trial shows that long-term administration of the P2y 12 antagonist clopidogrel is more effective than aspirin in reducing the combined risk of ischemic stroke, myocardial infarction, or vascular death in subjects with a prothrombotic condition such as diabetes mellitus type 2 (DM2). 7 These findings illustrate the crucial role of P2y 12 signaling in platelet activation in vitro and in vivo. Conclusion-TheThe importance of P2y 12 signaling is explained by its capacity to initiate 2 pathways that directly interfere with platelet activating or inhibiting mechanisms. First, there is the activation of the G-protein subunit G i ␣, which inhibits adenylyl cyclase and thereby formation of the platelet inhibitor cAMP. 8 This property is particularly evident after treatment with prostacyclin, 9 and also in the absence of cAMP elevating agents, P2y 12 signaling controls cAMP production through adenylyl cyclase. 10,11 cAMP inhibits platelets through cAMPdependent protein kinase (protein kinase A [PKA]), 12 which inhibits almost all platelet functions through blockade of multiple steps in platelet activation cascades including receptor activation, signaling through the mitogen-activated protein kinases pathway, formation of thromboxane A 2 (TxA 2 ), and the activation of key enzymes such as phospholipase C ␤ and protein kinase C (PKC). 13 Second, there is the release of the G i ␤␥ dimer leading to the activation ...

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“…Most likely this is due to the fact that hematopoietic stem cells differentiate along multiple, partially asynchronous routes. 32,33 It remains to be determined whether this alternative differentiation route is also followed in vivo.…”

Section: Discussionmentioning

confidence: 99%