Prolactin Receptor Signaling during Platelet Activation

Abstract

Prolactin is a newly recognized platelet coactivator that functions through potentiation of ADP-induced platelet activation. However, the possible association between hyperprolactinemia and venous thromboembolism (VTE) has not been systematically investigated up to now; prolactin signaling mechanisms in platelets still need to be elucidated. In this study, plasma prolactin levels in healthy subjects and patients with VTE were determined, demonstrating that patients with VTE and no other congenital risk factors had significantly increased plasma prolactin levels. Moreover, prolactinoma patients demonstrated a higher incidence of VTE than the general population. To elucidate the molecular mechanisms for the development of venous thrombosis, prolactin receptor signaling during platelet activation was investigated with a focus on ADP-stimulated G-protein-regulated signaling pathways. The short isoform of prolactin receptors was detected on platelets. Signaling through this receptor, although not directly linked to Gq-proteins, substitutes for Gq-protein regulated signaling pathways involved in platelet activation. We identified protein kinase C, a well-established signaling molecule in platelet activation, as a target molecule for prolactin signaling pathways in human platelets. Our findings indicate that hyperprolactinemia may be an important novel risk factor for VTE, suggesting that its thrombogenic effect may be mediated through enhanced platelet reactivity. Revealing the molecular mechanisms of prolactin signaling will allow the design of new antithrombotic therapies.

Key words

Prolactin - Thrombosis - Platelet activation - G proteins - Protein kinase C - Pituitary tumor

References

• 1 Heit J A, Silverstein M D, Mohr D N, Petterson T M, Lohse C M, O'Fallon W M, Melton L J. The epidemiology of venous thromboembolism in the community.  Thromb Haemost. 2001;  86 452-463
• 2 Rosendaal F R. Venous thrombosis: a multicausal disease.  Lancet. 1999;  353 1167-1173
• 3 Rosendaal F R. Venous thrombosis: prevalence and interaction of risk factors.  Haemostasis. 1999;  29 Suppl S1 1-9
• 4 Bates S M, Ginsberg J S. Thrombosis in pregnancy.  Curr Opin Hematol. 1997;  4 335-343
• 5 Greer I A. Thrombosis in pregnancy: maternal and fetal issues.  Lancet. 1999;  353 1258-1265
• 6 Wallaschofski H, Donné M, Eigenthaler M, Hentschel B, Faber R, Stepan H, Koksch M, Lohmann T. Prolactin as a novel potent cofactor for platelet aggregation.  J Clin Endocrinol Metab. 2001;  86 5912-5919
• 7 David S R, Taylor C C, Kinon B J, Breier A. The effects of olanzapine, risperidone, and haloperidol on plasma prolactin levels in patients with schizophrenia.  Clin Ther. 2000;  22 1085-1096
• 8 Zornberg G L, Jick H. Antipsychotic drug use and risk of first-time idiopathic venous thromboembolism: a case-control study.  Lancet. 2000;  356 1219-1223
• 9 Tripodi A, Mannucci P M. Laboratory investigation of thrombophilia.  Clin Chem. 2001;  47 1597-1606
• 10 Schwarz U R, Geiger J, Walter U, Eigenthaler M. Flow cytometry analysis of intracellular VASP phosphorylation for the assessment of activating and inhibitory signal transduction pathways in human platelets-definition and detection of ticlopidine/clopidogrel effects.  Thromb Haemost. 1999;  82 1145-1152
• 11 Geiger J, Honig-Liedl P, Schanzenbacher P, Walter U. Ligand specificity and ticlopidine effects distinguish three human platelet ADP receptors.  Eur J Pharmacol. 1998;  351 235-246
• 12 Oger E. Incidence of venous thromboembolism: a community-based study in Western France. EPI-GETBP Study Group. Groupe d'Etude de la Thrombose de Bretagne Occidentale.  Thromb Haemost. 2000;  83 657-660
• 13 White R H, Zhou H, Romano P S. Incidence of idiopathic deep venous thrombosis and secondary thromboembolism among ethnic groups in California.  Ann Intern Med. 1998;  128 737-740
• 14 Bellone G, Geuna M, Carbone A, Silvestri S, Foa R, Emanuelli G, Matera L. Regulatory action of prolactin on the in vitro growth of CD34+ human hemopoietic progenitor cells.  J Cell Physiol. 1995;  163 221-231
• 15 Draca S. Prolactin as an immunoreactive agent.  Immunol Cell Biol. 1995;  73 481-483
• 16 Jin J, Kunapuli S P. Coactivation of two different G protein-coupled receptors is essential for ADP-induced platelet aggregation.  Proc Natl Acad Sci U S A. 1998;  95 8070-8074
• 17 Savi P, Beauverger P, Labouret C, Delfaud M, Salel V, Kaghad M, Herbert J M. Role of P2Y1 purinoceptor in ADP-induced platelet activation.  FEBS Lett. 1998;  422 291-295
• 18 Daniel J L, Dangelmaier C, Jin J, Kim Y B, Kunapuli S P. Role of intracellular signaling events in ADP-induced platelet aggregation.  Thromb Haemost. 1999;  82 1322-1326
• 19 Keranen L M, Dutil E M, Newton A C. Protein kinase C is regulated in vivo by three functionally distinct phosphorylations.  Curr Biol. 1995;  5 1394-1403
• 20 Jin J, Daniel J L, Kunapuli S P. Molecular basis for ADP-induced platelet activation. II. The P2Y1 receptor mediates ADP-induced intracellular calcium mobilization and shape change in platelets.  J Biol Chem. 1998;  273 2030-2034
• 21 Celi A, Lorenzet R, Furie B, Furie B C. Platelet-leukocyte-endothelial cell interaction on the blood vessel wall.  Semin Hematol. 1997;  34 327-335
• 22 Merten M, Thiagarajan P. P-selectin expression on platelets determines size and stability of platelet aggregates.  Circulation. 2000;  102 1931-1936
• 23 Pulmonary Embolism Prevention trial  . Prevention of pulmonary embolism and deep vein thrombosis with low dose aspirin: Pulmonary Embolism Prevention (PEP) trial.  Lancet. 2000;  355 1295-1302
• 24 Collins R, Baigent C, Sandercock P, Peto R. Antiplatelet therapy for thromboprophylaxis: the need for careful consideration of the evidence from randomised trials. Antiplatelet Trialists'.  Bmj. 1994;  309 1215-1217
• 25 Antiplatelet Trialists' Collaboration. Collaborative overview of randomised trials of antiplatelet therapy-III: . Reduction in venous thrombosis and pulmonary embolism by antiplatelet prophylaxis among surgical and medical patients.  BMJ. 1994;  308 235-246
• 26 Molitch M E, Thorner M O, Wilson C. Management of prolactinomas.  J Clin Endocrinol Metab. 1997;  82 996-1000
• 27 Nagano M, Kelly P A. Tissue distribution and regulation of rat prolactin receptor gene expression. Quantitative analysis by polymerase chain reaction.  J Biol Chem. 1994;  269 13 337-13 345
• 28 Postel-Vinay M C. Growth hormone- and prolactin-binding proteins: soluble forms of receptors.  Horm Res. 1996;  45 178-181
• 29 Dardenne M, de Moraes M, Kelly P A, Gagnerault M C. Prolactin receptor expression in human hematopoietic tissues analyzed by flow cytofluorometry.  Endocrinology. 1994;  134 2108-2114
• 30 Rui H, Kirken R A, Farrar W L. Activation of receptor-associated tyrosine kinase JAK2 by prolactin.  J Biol Chem. 1994;  269 5364-5368
• 31 Goffin V, Kelly P A. The prolactin/growth hormone receptor family: structure/function relationships.  J Mammary Gland Biol. Neoplasia 1997;  2 7-17
• 32 Bole-Feysot C, Goffin V, Edery M, Binart N, Kelly P A. Prolactin (PRL) and its receptor: actions, signal transduction pathways and phenotypes observed in PRL receptor knockout mice.  Endocr Rev. 1998;  19 225-268
• 33 Frank D A. STAT signaling in the pathogenesis and treatment of cancer.  Mol Med. 1999;  5 432-456
• 34 Rao Y P, Buckley D J, Buckley A R. Rapid activation of mitogen-activated protein kinase and p21ras by prolactin and interleukin 2 in rat Nb2 node lymphoma cells.  Cell Growth Differ. 1995;  6 1235-1244
• 35 Erwin R A, Kirken R A, Malabarba M G, Farrar W L, Rui H. Prolactin activates Ras via signaling proteins SHC, growth factor receptor bound 2, and son of sevenless.  Endocrinology. 1995;  136 3512-3518
• 36 Clevenger C V, Torigoe T, Reed J C. Prolactin induces rapid phosphorylation and activation of prolactin receptor-associated RAF-1 kinase in a T-cell line.  J Biol Chem. 1994;  269 5559-5565
• 37 Peters C A, Maizels E T, Robertson M C, Shiu R P, Soloff M S, Hunzicker-Dunn M. Induction of relaxin messenger RNA expression in response to prolactin receptor activation requires protein kinase C delta signaling.  Mol Endocrinol. 2000;  14 576-590
• 38 Rao Y P, Buckley D J, Olson M D, Buckley A R. Nuclear translocation of prolactin: collaboration of tyrosine kinase and protein kinase C activation in rat Nb2 node lymphoma cells.  J Cell Physiol. 1995;  163 266-276
• 39 Vacher P, Tran V an, Paly J, Djiane J, Dufy B. Short term effect of prolactin on intracellular calcium in Chinese hamster ovary cells stably transfected with prolactin receptor complementary deoxyribonucleic acid.  Endocrinology. 1994;  134 1213-1218
• 40 Larrea F, Sanchez-Gonzalez S, Mendez I, Garcia-Becerra R, Cabrera V, Ulloa-Aguirre A. G protein-coupled receptors as targets for prolactin actions.  Arch Med Res. 1999;  30 532-543
• 41 Johansen P W, Lund H W, Gordeladze J O. Specific combinations of G-protein subunits discriminate hormonal signalling in rat pituitary (GH(3)) cells in culture.  Cell Signal. 2001;  13 251-256
• 42 Kline J B, Moore D J, Clevenger C V. Activation and association of the Tec tyrosine kinase with the human prolactin receptor: mapping of a Tec/Vav1-receptor binding site.  Mol Endocrinol. 2001;  15 832-841
• 43 Daniel J L, Dangelmaier C, Jin J, Ashby B, Smith J B, and K unapuli. Molecular basis for ADP-induced platelet activation. I. Evidence for three distinct ADP receptors on human platelets.  J Biol Chem. 1998;  273 2024-2029
• 44 Tibbles H E, Vassilev A, Wendorf H, Schonhoff D, Zhu D, Lorenz D, Waurzyniak B, Liu X P, Uckun F M. Role of a JAK3-dependent biochemical signaling pathway in platelet activation and aggregation.  J Biol Chem. 2001;  276 17 815-17 822