Dual-Specificity Phosphatase 3 Deficiency or Inhibition Limits Platelet Activation and Arterial Thrombosis

Abstract

Background A limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences. Better understanding of the molecular mechanisms leading to platelet activation is of importance for the development of improved therapies. Recently, protein tyrosine phosphatases (PTPs) have emerged as critical regulators of platelet function. Methods and Results This is the first report implicating the dual-specificity phosphatase 3 (DUSP3) in platelet signaling and thrombosis. This phosphatase is highly expressed in human and mouse platelets. Platelets from DUSP3-deficient mice displayed a selective impairment of aggregation and granule secretion mediated through the collagen receptor glycoprotein VI (GPVI) and the C-type lectin-like receptor 2 (CLEC-2). DUSP3-deficient mice were more resistant to collagen- and epinephrine-induced thromboembolism, compared to wild-type mice, and showed severely impaired thrombus formation upon ferric chloride-induced carotid artery injury. Intriguingly, bleeding times were not altered in DUSP3-deficient mice. At the molecular level, DUSP3 deficiency impaired Syk tyrosine phosphorylation, subsequently reducing phosphorylation of PLCγ2 and calcium fluxes. To investigate DUSP3 function in human platelets, a novel small-molecule inhibitor of DUSP3 was developed. This compound specifically inhibited collagen and CLEC-2-induced human platelet aggregation, thereby phenocopying the effect of DUSP3 deficiency in murine cells. Conclusions DUSP3 plays a selective and essential role in collagen- and CLEC-2-mediated platelet activation and thrombus formation in vivo. Inhibition of DUSP3 may prove therapeutic for arterial thrombosis. This is the first time a PTP, implicated in platelet signaling, has been targeted with a small-molecule drug.

Metformin Uniquely Prevents Thrombosis by Inhibiting Platelet Activation and mtDNA Release

“…4I). These findings are notable, because a known major limitation of current antithrombotic therapies is their inability to separate thrombotic events from bleeding occurrences31. And the mice treated with metformin did not show any spontaneous bleeding and had far less bleeding risk than those treated with aspirin (Fig.…”

“…However, current antiplatelet agents approved by the US Food and Drug Administration have serious side effects, including bleeding episodes, gastrointestinal toxicity, neutropenia and thrombocytopenia. As stated previously, a recognized limitation of current antiplatelet therapies is their inability to separate thrombotic events from bleeding occurrences313334. The impact of metformin on hemostatic function is best exemplified by our tail bleeding time studies and chronic-type gastric ulcer evaluation.…”

Xanthohumol isolated from Humulus lupulus prevents thrombosis without increased bleeding risk by inhibiting platelet activation and mtDNA release

“…A well-known major limitation of current antithrombotic therapies is their inability to separate thrombotic events from bleeding occurrences [6]. Interestingly, the XN treatment did not significantly prolong bleeding time in rats (Fig.…”

“…Another million experience a thrombotic cerebrovascular accident, and DVT (deep vein thrombosis) is a major problem for surgical and other hospitalized patients [1,2,5,49,50]. However, current antithrombotic agents have serious side effects, mainly bleeding episodes [6]. Therefore, development of a novel, more effective antithrombotic drug with minimal side effects is urgently needed.…”

“…In addition, previous work has shown that 10—40% of patients are biochemically resistant to aspirin, which is commonly used in clinical practice to prevent and treat thrombosis. Therefore, the development of novel antithrombotic drugs or antiplatelet drugs with minimal side effects is urgently needed [6]. …”