Abstract Number: PB1020
Meeting: ISTH 2021 Congress
Background: Rhabdomyolysis is a syndrome due to the breakdown of skeletal muscle caused by various reasons. The most serious complication is acute kidney injury (AKI), which is sometimes fatal, however, no effective treatment has been established. According to a recent study, heme (hemin) released from damaged muscles activates platelets, and the activated platelets induce macrophage extracellular traps (METs), resulting in exacerbation of AKI. We have reported in the last ISTH that hemin binds directly to CLEC-2 and GPVI and activates platelets via the SFK-SYK-PLCγ2 pathway, and in rhabdomyolysis mouse model, deletion of CLEC-2 and GPVI reduces renal dysfunction and METs-like structures in the kidney.
Aims: To elucidate the detailed mechanisms of 1) binding of hemin to CLEC-2/GPVI and 2) METs induction by hemin-activated platelets.
Methods: 1)-1 We performed hemin-induced platelet aggregation assay with Co-HP/anti-GPVI antibody, which inhibit the binding known ligands to CLEC-2/GPVI respectively.
1)-2 Using CLEC-2/GPVI-expressing cell lines, we performed the competitive binding assay by flow cytometry to investigate whether hemin competes with known ligands.
2) To examine whether hemin-activated platelets promote MET formation via platelet SFK pathway, we co-cultured hemin-activated platelets and macrophages with or without SFK inhibitor, and evaluated MET formation.
Results: 1)-1 Co-HP or anti-GPVI antibody inhibited hemin-induced platelet aggregation in FcRγ/GPVI deficient mice or CLEC-2 depleted mice, respectively.
1)-2 Hemin inhibited binding of podoplanin or CRP to CLEC-2 or GPVI respectively.
2) METs induced by heme-activated platelets were suppressed by the addition of SFK inhibitor to platelets.
Conclusions: These results suggest that 1) hemin shares the binding sites with known ligands for CLEC-2 and GPVI, and 2) the SFK pathway in platelet, which exists downstream of CLEC-2/GPVI, is important for the induction of METs by hemin-activated platelets.
To cite this abstract in AMA style:Oishi S, Tsukiji N, Otake S, Oishi N, Sasaki T, Shirai T, Yoshikawa Y, Takano K, Shinmori H, Inukai T, Kondo T, Suzuki-Inoue K. The Role of Platelet CLEC-2 and GPVI in Rhabdomyolysis-induced Acute Kidney Injury [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/the-role-of-platelet-clec-2-and-gpvi-in-rhabdomyolysis-induced-acute-kidney-injury/. Accessed November 29, 2021.
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