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DOI: 10.1160/TH15-05-0429
Developmental endothelial locus-1 modulates platelet-monocyte interactions and instant blood-mediated inflammatory reaction in islet transplantation
Publication History
Received:
26 May 2015
Accepted after major revision:
25 November 2015
Publication Date:
28 November 2017 (online)


Summary
Platelet-monocyte interactions are strongly implicated in thrombo-inflammatory injury by actively contributing to intravascular inflammation, leukocyte recruitment to inflamed sites, and the amplification of the procoagulant response. Instant blood-mediated inflammatory reaction (IBMIR) represents thrombo-inflammatory injury elicited upon pancreatic islet transplantation (islet-Tx), thereby dramatically affecting transplant survival and function. Developmental endothelial locus-1 (Del-1) is a functionally versatile endothelial cell-derived homeostatic factor with anti-inflammatory properties, but its potential role in IBMIR has not been previously addressed. Here, we establish Del-1 as a novel inhibitor of IBMIR using a whole blood–islet model and a syngeneic murine transplantation model. Indeed, Del-1 pre-treatment of blood before addition of islets diminished coagulation activation and islet damage as assessed by C-peptide release. Consistently, intraportal islet-Tx in transgenic mice with endothelial cell-specific overexpression of Del-1 resulted in a marked decrease of monocytes and platelet-monocyte aggregates in the transplanted tissues, relative to those in wild-type recipients. Mechanistically, Del-1 decreased platelet-monocyte aggregate formation, by specifically blocking the interaction between monocyte Mac-1-integrin and platelet GPIb. Our findings reveal a hitherto unknown role of Del-1 in the regulation of platelet-monocyte interplay and the subsequent heterotypic aggregate formation in the context of IBMIR. Therefore, Del-1 may represent a novel approach to prevent or mitigate the adverse reactions mediated through thrombo-inflammatory pathways in islet-Tx and perhaps other inflammatory disorders involving platelet-leukocyte aggregate formation.
Supplementary Material to this article is available online at www.thrombosis-online.com.
Keywords
Instant blood-mediated inflammatory reaction (IBMIR) - Developmental endothelial locus 1 (Del-1) - coagulation - platelet-monocyte aggregates - islet transplantation - GPIb, Mac-1 integrin* I. K. and K. K. contributed equally to this work.