Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization
Platelet G protein-coupled receptors (GPCRs) regulate platelet function by mediating the response to various agonists, including adenosine diphosphate (ADP), thromboxane A<sub>2</sub>, and thrombin. Although GPCR kinases (GRKs) are considered to have the crucial roles in most GPCR functi...
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MDPI AG
2020-05-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/21/11/3932 |
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| author | Preeti Kumari Chaudhary Sanggu Kim Youngheun Jee Seung-Hun Lee Kyung-Mee Park Soochong Kim |
| author_facet | Preeti Kumari Chaudhary Sanggu Kim Youngheun Jee Seung-Hun Lee Kyung-Mee Park Soochong Kim |
| author_sort | Preeti Kumari Chaudhary |
| collection | DOAJ |
| description | Platelet G protein-coupled receptors (GPCRs) regulate platelet function by mediating the response to various agonists, including adenosine diphosphate (ADP), thromboxane A<sub>2</sub>, and thrombin. Although GPCR kinases (GRKs) are considered to have the crucial roles in most GPCR functions, little is known regarding the regulation of GPCR signaling and mechanisms of GPCR desensitization by GRKs in platelets. In this study, we investigated the functional role of GRK6 and the molecular basis for regulation of specific GPCR desensitization by GRK6 in platelets. We used GRK6 knockout mice to evaluate the functional role of GRK6 in platelet activation. Platelet aggregation, dense- and α-granule secretion, and fibrinogen receptor activation induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in GRK6<sup>−/−</sup> platelets compared to the wild-type (WT) platelets. However, collagen-related peptide (CRP)-induced platelet aggregation and secretion were not affected in GRK6<sup>−/−</sup> platelets. Interestingly, platelet aggregation induced by co-stimulation of serotonin and epinephrine which activate G<sub>q</sub>-coupled 5HT<sub>2A</sub> and G<sub>z</sub>-coupled α<sub>2A</sub> adrenergic receptors, respectively, was not affected in GRK6<sup>−/−</sup> platelets, suggesting that GRK6 was involved in specific GPCR regulation. In addition, platelet aggregation in response to the second challenge of ADP and AYPGKF was restored in GRK6<sup>−/−</sup> platelets whereas re-stimulation of the agonist failed to induce aggregation in WT platelets, indicating that GRK6 contributed to P2Y<sub>1</sub>, P2Y<sub>12</sub>, and PAR4 receptor desensitization. Furthermore, 2-MeSADP-induced Akt phosphorylation and AYPGKF-induced Akt, extracellular signal-related kinase (ERK), and protein kinase Cδ (PKCδ) phosphorylation were significantly potentiated in GRK6<sup>−/−</sup> platelets. Finally, GRK6<sup>−/−</sup> mice exhibited an enhanced and stable thrombus formation after FeCl<sub>3</sub> injury to the carotid artery and shorter tail bleeding times, indicating that GRK6<sup>−/−</sup> mice were more susceptible to thrombosis and hemostasis. We conclude that GRK6 plays an important role in regulating platelet functional responses and thrombus formation through selective GPCR desensitization. |
| first_indexed | 2024-03-10T19:28:48Z |
| format | Article |
| id | doaj.art-87403c45b4204915aeed863029923638 |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T19:28:48Z |
| publishDate | 2020-05-01 |
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| spelling | doaj.art-87403c45b4204915aeed8630299236382023-11-20T02:18:37ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672020-05-012111393210.3390/ijms21113932Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) DesensitizationPreeti Kumari Chaudhary0Sanggu Kim1Youngheun Jee2Seung-Hun Lee3Kyung-Mee Park4Soochong Kim5College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, KoreaCollege of Veterinary Medicine, Chungbuk National University, Cheongju 28644, KoreaCollege of Veterinary Medicine and Veterinary Medical Research Institute, Jeju National University, Jeju 63243, KoreaCollege of Veterinary Medicine, Chungbuk National University, Cheongju 28644, KoreaCollege of Veterinary Medicine, Chungbuk National University, Cheongju 28644, KoreaCollege of Veterinary Medicine, Chungbuk National University, Cheongju 28644, KoreaPlatelet G protein-coupled receptors (GPCRs) regulate platelet function by mediating the response to various agonists, including adenosine diphosphate (ADP), thromboxane A<sub>2</sub>, and thrombin. Although GPCR kinases (GRKs) are considered to have the crucial roles in most GPCR functions, little is known regarding the regulation of GPCR signaling and mechanisms of GPCR desensitization by GRKs in platelets. In this study, we investigated the functional role of GRK6 and the molecular basis for regulation of specific GPCR desensitization by GRK6 in platelets. We used GRK6 knockout mice to evaluate the functional role of GRK6 in platelet activation. Platelet aggregation, dense- and α-granule secretion, and fibrinogen receptor activation induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in GRK6<sup>−/−</sup> platelets compared to the wild-type (WT) platelets. However, collagen-related peptide (CRP)-induced platelet aggregation and secretion were not affected in GRK6<sup>−/−</sup> platelets. Interestingly, platelet aggregation induced by co-stimulation of serotonin and epinephrine which activate G<sub>q</sub>-coupled 5HT<sub>2A</sub> and G<sub>z</sub>-coupled α<sub>2A</sub> adrenergic receptors, respectively, was not affected in GRK6<sup>−/−</sup> platelets, suggesting that GRK6 was involved in specific GPCR regulation. In addition, platelet aggregation in response to the second challenge of ADP and AYPGKF was restored in GRK6<sup>−/−</sup> platelets whereas re-stimulation of the agonist failed to induce aggregation in WT platelets, indicating that GRK6 contributed to P2Y<sub>1</sub>, P2Y<sub>12</sub>, and PAR4 receptor desensitization. Furthermore, 2-MeSADP-induced Akt phosphorylation and AYPGKF-induced Akt, extracellular signal-related kinase (ERK), and protein kinase Cδ (PKCδ) phosphorylation were significantly potentiated in GRK6<sup>−/−</sup> platelets. Finally, GRK6<sup>−/−</sup> mice exhibited an enhanced and stable thrombus formation after FeCl<sub>3</sub> injury to the carotid artery and shorter tail bleeding times, indicating that GRK6<sup>−/−</sup> mice were more susceptible to thrombosis and hemostasis. We conclude that GRK6 plays an important role in regulating platelet functional responses and thrombus formation through selective GPCR desensitization.https://www.mdpi.com/1422-0067/21/11/3932GRK6GPCRPARADPdesensitizationplatelets |
| spellingShingle | Preeti Kumari Chaudhary Sanggu Kim Youngheun Jee Seung-Hun Lee Kyung-Mee Park Soochong Kim Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization International Journal of Molecular Sciences GRK6 GPCR PAR ADP desensitization platelets |
| title | Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization |
| title_full | Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization |
| title_fullStr | Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization |
| title_full_unstemmed | Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization |
| title_short | Role of GRK6 in the Regulation of Platelet Activation through Selective G Protein-Coupled Receptor (GPCR) Desensitization |
| title_sort | role of grk6 in the regulation of platelet activation through selective g protein coupled receptor gpcr desensitization |
| topic | GRK6 GPCR PAR ADP desensitization platelets |
| url | https://www.mdpi.com/1422-0067/21/11/3932 |
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