Platelet-derived microvesicles promote endothelial progenitor cell proliferation in intimal injury by delivering
Jing Yan1, Han Bao1, Yang-Jing Fan1
1Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, China.
Abstract:
Intimal injury is an early stage of several cardiovascular diseases. Endothelial progenitor cells (EPCs) play a significant role in endothelial repair following vascular injury. Once the intima is damaged, EPCs are mobilized from the bone marrow to the injury site. Meanwhile, the injury to the intimal surface triggers platelet degranulation, aggregation, and adhesion to the damaged endothelium, and exposed collagen stimulates platelet to secrete platelet-derived microvesicles (PMVs). However, the role of PMVs in EPC function during this process remains unknown. In an in vivo study, EPCs and platelets were found to adhere to the injury site in Sprague-Dawley (SD) rat vascular injury model. In vitro, collagen stimulation induced the release of PMVs, and collagen-activated PMVs (ac.PMVs) significantly promoted EPC proliferation. Transforming growth factor-β1 (TGF-β1) content was increased in ac.PMVs. Activated PMVs significantly upregulated Smad3 phosphorylation in EPCs and increased Smad3 nuclear translocation from the cytoplasm. TGF-β1 knockdown ac.PMVs downregulated EPC proliferation. Recombinant TGF-β1 enhanced EPC proliferation. The TGF-β1 inhibitor SB431542 significantly repressed the intracellular signal triggered by ac.PMVs. Furthermore, the Smad3-specific phosphorylation inhibitor SIS3 effectively reversed the cell proliferation induced by ac.PMVs. Smad3 translocated to the nucleus and enhanced EPC proliferation via its downstream genes tenascin C (TNC), CDKN1A, and CDKN2A. r-TGF-β1 promoted reendothelialization and EPC proliferation in vivo. Our data demonstrate that activated PMVs deliver TGF-β1 from collagen-activated platelets to EPCs, which in turn activates Smad3 phosphorylation and regulates TNC, CDKN1A, and CDKN2A expression to promote EPC proliferation, suggesting that PMVs act as a key transporter and a potential therapeutic target for vascular injury.
More Related Videos
11:35Decellularization and Recellularization Methodology for Human Saphenous Veins
Published on: July 27, 2018
09:34Visualizing Angiogenesis by Multiphoton Microscopy In Vivo in Genetically Modified 3D-PLGA/nHAp Scaffold for Calvarial Critical Bone Defect Repair
Published on: September 7, 2017
Related Concept Videos
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Clot Retraction and Fibrinolysis
Structure and Function of Platelets
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
Mechanism of Angiogenesis
Regulation of Angiogenesis and Blood Supply
Intracellular Signaling Affects Focal Adhesions
Some...
