ASGR1 expressed by porcine enriched liver sinusoidal endothelial cells mediates human platelet phagocytosis in vitro

Leela L. Paris, Ray K. Chihara, Luz M. Reyes, Richard A. Sidner, Jose L. Estrada, Susan M. Downey, Daniel A. Milgrom, A. Joseph Tector, Christopher Burlak

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Background: Porcine liver xenografts represent a potential solution to the organ shortage, but thrombocytopenia occurs within minutes to hours after xenotransplantation, preventing clinical application. Recently, it was discovered that porcine liver sinusoidal endothelial cells (LSEC) bind and phagocytose human platelets. We examined the role of ASGR1 in binding and removing human platelets by the pig liver endothelium. Methods: Primary porcine enriched LSEC (eLSEC) were characterized by flow cytometry, immunoblot, quantitative PCR, and immunohistochemistry using confocal microscopy. Phagocytosis inhibition assays using anti-ASGR1 and an ASGR1 substrate were performed. ASGR1 was targeted for siRNA knockdown, and ASGR1-reduced cells were tested for human platelet binding and phagocytosis. Results: ASGR1 is expressed by eLSEC. Human platelet binding and phagocytosis by porcine eLSEC was inhibited by asialofetuin, but not fetuin, suggesting an interaction with galactose β1-4 N-acetyl glucosamine. Anti-ASGR1 antibodies inhibited human platelet binding in a dose-dependent manner. Knockdown experiments using siRNA reduced ASGR1 expression in asynchronous primary eLSEC by 40%-80%. There was a 20% reduction in translated protein significantly correlated with a 21% decrease in human platelet binding. Conclusions: ASGR1 on porcine eLSEC mediates phagocytosis of xenogeneic platelets.

Original languageEnglish (US)
Pages (from-to)245-251
Number of pages7
JournalXenotransplantation
Volume18
Issue number4
DOIs
StatePublished - Jan 1 2011

Keywords

  • asialoglycoprotein receptor-1
  • endothelial cell
  • phagocytosis
  • thrombocytopenia
  • xenotransplantation

ASJC Scopus subject areas

  • Transplantation
  • Immunology

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    Paris, L. L., Chihara, R. K., Reyes, L. M., Sidner, R. A., Estrada, J. L., Downey, S. M., Milgrom, D. A., Tector, A. J., & Burlak, C. (2011). ASGR1 expressed by porcine enriched liver sinusoidal endothelial cells mediates human platelet phagocytosis in vitro. Xenotransplantation, 18(4), 245-251. https://doi.org/10.1111/j.1399-3089.2011.00639.x