PI3 kinase dependent regulation of ion channels and carriers in platelets

• Applicant: Professor Dr. Oliver Borst
• Subject Area: Cardiology, Angiology ; Anatomy and Physiology
• Term: from 2011 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 190538538

Final Report Abstract

In the context of the funding, we could show that chemokines (such as CXCL12/SDF-1, or CXCL16) released by platelets are involved in the induction and maintenance of vascular inflammation and additionally are able to trigger platelet activation in inflammation-associated arterial thrombosis. In addition, we have been able to identify major intracellular signaling cascades, which are predisposed to a process of arterial thrombosis and thrombo-inflammation. As a result of our research, we could show that the chemokine CXCL16 stimulates platelet secretion, integrin αIIbβ3 activation, and platelet adhesion in vivo to injured endothelium via a phosphatidylinositide 3-kinase (PI3K)/Akt-dependent signaling cascade, and is chosen as an important biochemical marker of vascular inflammation and consecutive arterial thrombosis. In addition, beside Akt (also named as protein kinase B/PKB), we were able to prove for the first time that two further so called AGC kinases, serum- and glucocorticoidinducible kinase-1 (SGK1) and phosphoinositide-dependent kinase-1 (PDK1), play a decisive role in platelet activation and arterial thrombosis. Downstream of PI3K, the SGK1 critically regulates the platelet calcium channel Orai1 and thus controls the store-operated calcium entry (SOCE) during Ca2+-dependent platelet activation. Further, we could identify the GTPase Rab27b as a further important downstream target of SGK1 in platelets, crucially involved in platelet granule biogenesis and secretion. PDK1 reflects another kinase activated downstream of PI3K. In platelets, PDK1 seems to be decisive for the activation of the GTPase Rac-1 and the mobilization of intracellular Ca2+ via induction of phospholipase γ2 (PLCγ2). A platelet-specific knockout was shown to protect mice with PDK1 deficiency from development of arterial thrombosis and ischemic stroke in vivo. Another kinase interacting with the AGC kinase Akt is the casein kinase 2 (CK2). By means of a platelet-specific knockout of the regulatory β-subunit we were able to show that CK2β is of critical importance not only for the regulation of platelet inositol triphosphate (IP3)-dependent Ca2+ mobilization from intracellular stores but also for the generation of platelets (the so-called thrombopoiesis). Beside these observations we could identify some important modulators of platelet membrane integrity and regulators of processes in the platelet membrane triggering thrombin generation during arterial thrombosis such as the acid sphingomyelinase aSM (also named as sphingomyelin phosphodiesterase-1 [Smpd1]).

Publications

• (2012) Chorein-sensitive polymerization of cortical actin and suicidal cell death in choreaacanthocytosis. FASEB J., 26, 1526-34
  Föller, M., Hermann, A., Gu, S., Alesutan, I., Qadri, S.M., Borst, O., Schmidt, E.M., Schiele, F., vom Hagen, J.M., Saft, C., Schöls, L., Lerche, H., Stournaras, C., Storch, A., Lang, F.
  
• (2012) Dynamic adhesion of eryptotic erythrocytes to endothelial cells via CXCL16/SR-PSOX. Am J Physiol Cell Physiol., 302, C644-51
  Borst, O., Abed, M., Alesutan, I., Towhid, S.T., Qadri, S.M., Föller, M., Gawaz, M., Lang, F.
  
• (2012) Intracellular cyclophilin A is an important Ca(2+) regulator in platelets and critically involved in arterial thrombus formation. Blood, 120, 1317-26
  Elvers, M., Herrmann, A., Seizer, P., Münzer, P., Beck, S., Schönberger, T., Borst, O., Martin- Romero, F.J., Lang, F., May, A.E., Gawaz, M.
  
• (2012) Sphingomyelinase-induced adhesion of eryptotic erythrocytes to endothelial cells. Am J Physiol Cell Physiol. 303, C991-9
  Abed, M., Towhid, S.T., Mia, S., Pakladok, T., Alesutan, I., Borst, O., Gawaz, M., Gulbins, E., Lang, F.
  
• (2012) Stimulation of platelet apoptosis by peptidoglycan from Staphylococcus aureus 113. Apoptosis, 17, 998-1008
  Towhid, S.T., Nega, M., Schmidt, E.M., Schmid, E., Albrecht, T., Münzer, P., Borst, O., Götz, F., Lang, F.
  
• (2012) The inflammatory chemokine CXC motif ligand 16 triggers platelet activation and adhesion via CXC motif receptor 6- dependent phosphatidylinositide 3-kinase/Akt signaling. Circ Res., 111, 1297-307
  Borst, O., Münzer, P., Gatidis, S., Schmidt, E.M., Schönberger, T., Schmid, E., Towhid, S.T., Stellos, K., Seizer, P., May, A.E., Lang, F., Gawaz, M.
  
• (2012) The serum- and glucocorticoid-inducible kinase 1 (SGK1) influences platelet calcium signaling and function by regulation of Orai1 expression in megakaryocytes. Blood, 119,251-61
  Borst, O., Schmidt, E.M., Münzer, P., Schönberger, T., Towhid, S.T., Elvers, M., Leibrock, C., Schmid, E., Eylenstein, A., Kuhl, D., May, A.E., Gawaz, M., Lang, F.
  
• (2013) Chorein sensitivity of cytoskeletal organization and degranulation of platelets. FASEB J. 27, 2799-806
  Schmidt, E.M., Schmid, E., Münzer, P., Hermann, A., Eyrich, A.K., Russo, A., Walker, B., Gu, S., vom Hagen, J.M., Faggio, C., Schaller, M., Föller, M., Schöls, L., Gawaz, M., Borst, O., Storch, A., Stournaras, C., Lang, F.
  
• (2013) Increased platelet Ca2+ channel Orai1 expression upon platelet activation and in patients with acute myocardial infarction. Thromb Haemost. 110, 386-9
  Tolios, A., Gatidis, S., Münzer, P., Liu, G., Towhid, S.T., Karathanos, A., Tavlaki, E., Geisler, T., Seizer, P., May, A.E., Bigalke, B., Borst, O., Gawaz, M., Lang, F.
  
• (2013) Regulation of STIM1/Orai1-dependent Ca2+ signalling in platelets. Thromb Haemost., 110, 925-30
  Lang, F., Münzer, P., Gawaz, M., Borst, O.
  
• (2014) 1,25(OH)2 vitamin D3-dependent inhibition of platelet Ca2+ signaling and thrombus formation in klotho-deficient mice. FASEB J. 28, 2108-19
  Borst, O., Münzer, P., Schmid, E., Schmidt, E.M., Russo, A., Walker, B., Yang, W., Leibrock, C., Szteyn, K., Schmidt, S., Elvers, M., Faggio, C., Shumilina, E., Kuro-o, M., Gawaz, M., Lang, F.
  
• (2014) Acid sphingomyelinase regulates platelet cell membrane scrambling, secretion, and thrombus formation. Arterioscler Thromb Vasc Biol. 34, 61-71
  Münzer, P., Borst, O., Walker, B., Schmid, E., Feijge, M.A., Cosemans, J.M., Chatterjee, M., Schmidt, E.M., Schmidt, S., Towhid, S.T., Leibrock, C., Elvers, M., Schaller, M., Seizer, P., Ferlinz, K., May, A.E., Gulbins, E., Heemskerk, J.W., Gawaz, M., Lang, F.
  
• (2016) CD44 sensitivity of platelet activation, membrane scrambling and adhesion under high arterial shear rates. Thromb Haemost., 115, 99-108
  Liu, G., Liu, G., Alzoubi, K., Chatterjee, M., Walker, B., Münzer, P., Luo, D., Umbach, A.T., Elvira, B., Chen, H., Voelkl, J., Föller, M., Mak, T.W., Borst, O., Gawaz, M., Lang, F.
  
• (2016) PDK1 Determines Collagen- Dependent Platelet Ca2+ Signaling and Is Critical to Development of Ischemic Stroke In Vivo. Arterioscler Thromb Vasc Biol., 36, 1507-16
  Münzer, P., Walker-Allgaier, B., Geue, S., Geuss, E., Hron, G., Rath, D., Eißler, D., Winter, S., Schaeffeler, E., Meinert, M., Schaller, M., Greinacher, A., Schwab, M., Geisler, T., Kleinschnitz, C., Lang, F., Gawaz, M., Borst, O.
  
• (2017) CK2β regulates thrombopoiesis and Ca2+-triggered platelet activation in arterial thrombosis. Blood,130, 2774-2785
  Münzer, P., Walker-Allgaier, B., Geue, S., Langhauser, F., Geuss, E., Stegner, D., Aurbach, K., Semeniak, D., Chatterjee, M., Gonzalez Menendez, I., Märklin, M., Quintanilla-Martinez, L., Salih, H.R., Litchfield, D.W., Buchou, T., Kleinschnitz, C., Lang, F., Nieswandt, B., Pleines, I., Schulze, H., Gawaz, M., Borst, O.
  
• (2017) Doxepin inhibits GPVI-dependent platelet Ca2+ signaling and collagen-dependent thrombus formation. Am J Physiol Cell Physiol.,312, C765-C774
  Geue, S., Walker-Allgaier, B., Eißler, D., Tegtmeyer, R., Schaub, M., Lang, F., Gawaz, M., Borst, O., Münzer, P.
  
• (2017) SGK1 up-regulates Orai1 expression and VSMC migration during neointima formation after arterial injury. Thromb Haemost.,117, 1002-1005
  Walker-Allgaier, B., Schaub, M., Alesutan, I., Voelkl, J., Geue, S., Münzer, P., Rodríguez, J.M., Kuhl, D., Lang, F., Gawaz, M., Borst, O.
  
• (2018) Identification of key lipids critical for platelet activation by comprehensive analysis of the platelet lipidome. Blood, 132, e1-e12
  Peng, B., Geue, S., Coman, C., Münzer, P., Kopczynski, D., Has, C., Hoffmann, N., Manke, M.C., Lang, F., Sickmann, A., Gawaz, M., Borst, O., Ahrends, R.
  
• (2018) Inhibitory mechanisms of very lowdose rivaroxaban in non-ST-elevation myocardial infarction. Blood Adv., 2, 715-730
  Borst, O., Münzer, P., Alnaggar, N., Geue, S., Tegtmeyer, R., Rath, D., Droppa, M., Seizer, P., Heitmeier, S., Heemskerk, J.W.M., Jennings, L.K., Storey, R.F., Angiolillo, D.J., Rocca, B., Spronk, H., Ten Cate, H., Gawaz, M., Geisler, T.
  
• (2018) PDK1 governs thromboxane generation and thrombosis in platelets by regulating activation of Raf1 in the MAPK pathway. J Thromb Haemost., 16, 1211-1225
  Manne, B.K., Münzer, P., Badolia, R., Walker-Allgaier, B., Campbell, R.A., Middleton, E., Weyrich, A.S., Kunapuli, S.P., Borst, O., Rondina, M.T.