Synergistic effect of collagen and CXCL12 in the low doses on human platelet activation.

Daiki Nakashima,Yukiko Enomoto,Shinji Ogura,Masanori Tsujimoto,Toru Iwama,Tomoaki Doi,Kumiko Tanabe,Kodai Uematsu,Daisuke Mizutani,Yuko Kito,Hiroki Iida,Osamu Kozawa,Takashi Onuma,Rie Matsushima-Nishiwaki,Haruhiko Tokuda,Yong Jiang

doi:10.1371/journal.pone.0241139

Daiki Nakashima, Yukiko Enomoto + Show 14 more

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https://doi.org/10.1371/journal.pone.0241139

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Abstract

CXCL12, also known as stromal cell-derived factor-1, is a chemokine classified into CXC families, which exerts its function by binding to specific receptors called CXCR4 and CXCR7. Human platelets express CXCR4 and CXCR7 on the plasma membrane. It has been reported that CXCL12 potentiates to induce platelet aggregation in cooperation with agonists including collagen. However, the precise roles and mechanisms of CXCL12 in human platelet activation are not fully elucidated. In the present study, we investigated the effect of simultaneous stimulation with low doses of collagen and CXCL12 on the activation of human platelets. The simultaneous stimulation with collagen and CXCL12 induced the secretion of platelet-derived growth factor (PDGF)-AB and the release of soluble CD40 ligand (sCD40L) from human platelets in addition to their aggregation, despite the fact that the simultaneous stimulation with thrombin receptor-activating peptide (TRAP) or adenosine diphosphate (ADP), and CXCL12 had little effects on the platelet aggregation. The agonist of Glycoprotein (GP) Ⅵ convulxin and CXCL12 also induced platelet aggregation synergistically. The monoclonal antibody against CXCR4 but not CXCR7 suppressed the platelet aggregation induced by simultaneous stimulation with collagen and CXCL12. The phosphorylation of p38 mitogen-activated protein kinase (MAPK), but not p44/p42 MAPK, was induced by the simultaneous stimulation. In addition, the simultaneous stimulation with collagen and CXCL12 induced the phosphorylation of HSP27 and the subsequent release of phosphorylated-HSP27 from human platelets. SB203580, a specific inhibitor of p38 MAPK, attenuated the platelet aggregation, the phosphorylation of p38 MAPK and HSP27, the PDGF-AB secretion, the sCD40L release and the phosphorylated-HSP27 release induced by the simultaneous stimulation with collagen and CXCL12. These results strongly suggest that collagen and CXCL12 in low doses synergistically act to induce PDGF-AB secretion, sCD40L release and phosphorylated-HSP27 release from activated human platelets via p38 MAPK activation.

Highlights

CXCL12, called stromal cell-derived factor-1, is a chemokine classified into CXC families, heparin-binding proteins that direct the movement of circulating leukocytes to sites of inflammation or injury [1]
We evaluated the dose-response curves of the synergistic effects of collagen and CXCL12 in human platelet aggregation
We examined the effect of the Collagen and CXCL12 in platelets simultaneous stimulation of various doses (0.05 μg/ml, 0.1 μg/ml and 0.2 μg/ml) of collagen with a fixed dose (10 ng/ml) of CXCL12 on the platelet aggregation

Summary

Introduction

CXCL12, called stromal cell-derived factor-1, is a chemokine classified into CXC families, heparin-binding proteins that direct the movement of circulating leukocytes to sites of inflammation or injury [1]. CXCL12 is involved in essential physiological processes such as embryogenesis, hematopoiesis and angiogenesis [3,4], and acts on many migrating cells and tissues such as primordial germ cells, neurons, lymphocytes, endothelial precursor cells and hematopoietic stem cells [3,4]. Megakaryocyte lineage cells from colony forming units-megakaryocytes to mature megakaryocytes express CXCR4, and the CXCL12-CXCR4 axis is required to insert mature megakaryocytes into the appropriate vascular niche, a crucial process in platelet biogenesis [5]. Platelet-derived CXCL12 is known to modulate paracrine mechanisms such as chemotaxis, adhesion, proliferation and differentiation of nucleated cells including progenitor cells, and enhances their recruitment to sites of vascular and tissue injury, resulting in the promotion of repair [2]. Evidence supporting the function of CXCL12 in human platelet activation is accumulating, the precise roles and mechanism underlying the involvement of CXCL12 in human platelet activation have yet to be fully clarified

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