Thromb Haemost 2013; 109(06): 1079-1090
DOI: 10.1160/TH12-12-0894
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Endothelial cell phagocytosis of senescent neutrophils decreases procoagulant activity

Chunyan Gao
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Rui Xie
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Wen Li#
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Jin Zhou
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Shuchuan Liu
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Fenglin Cao
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Yue Liu
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Ruishuang Ma
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Yu Si
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Yan Liu
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
,
Yayan Bi
2   Department of Cardiology, The First Affiliated Hospital, Harbin Medical University, Harbin, China
,
Gary E. Gilbert
3   Department of Medicine, VA Boston Healthcare System, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts, USA
,
Jialan Shi
1   Heilongjiang Institute of Hematology and Oncology, Department of Hematology, Harbin, China
3   Department of Medicine, VA Boston Healthcare System, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachussetts, USA
› Author Affiliations

Financial support: This work was supported by grants from the National Natural Science Foundation of China (30871227 and 81270588), and the Science Foundation of Heilongjiang Province (GB08C401–02).
Further Information

Publication History

Received: 05 December 2012

Accepted after major revision: 14 March 2013

Publication Date:
22 November 2017 (online)

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Summary

Abundant senescent neutrophils traverse the vascular compartment and may contribute to pathologic conditions. For example, they become procoagulant when undergoing apoptosis and may contribute to thrombosis or inflammation. Our previous studies demonstrated a dominant clearance pathway in which the neutrophils can be phagocytosed by liver macrophages. The aim of this study was to explore an alternate pathway of neutrophil clearance by endothelial cells. Phagocytosis of the neutrophils by endothelial cells was performed using various experimental approaches including flow cytometry, confocal microscopy and electron microscopy assays in vitro and in vivo. Procoagulant activity of cultured neutrophils was evaluated by coagulation time, factor Xase and prothrombinase assays. Lactadherin functioned as a novel probe for the detection of phosphatidylserine on apoptotic cells, an opsonin (bridge) between apoptotic cell and phagocyte for promoting phagocytosis, and an efficient anticoagulant for inhibition of factor Xase and thrombin formation. When cultured, purified human neutrophils spontaneously entered apoptosis and developed procoagulant activity that was directly related to the degree of phosphatidylserine exposure. Co-culture of aged neutrophils and endothelial cells resulted in phagocytosis of the neutrophils and prolonged coagulation time. Lactadherin diminished the procoagulant activity and increased the rate of neutrophil clearance. In vivo, neutrophils were sequestered by endothelial cells after blockade of Kupffer cells, a process that was dependent upon both phosphatidylserine exposure and P-selectin expression. Thus, the ability of endothelial cells to clear senescent neutrophils may limit the procoagulant and/or inflammatory impact of these cells.

# Wen Li is currently at the Dept. of Endocrinology, the 3rd People’s Hospital of Yunnan Province, Kunming, China.