Abstract Number: PB1731
Meeting: ISTH 2020 Congress
Background: Platelet C-type lectin-like receptor (CLEC) 2 has been proposed as a potential anti-thrombotic target, based on animal studies suggesting a role in thrombosis. Moreover, it could also be an anti-tumour target as its endogenous ligand, podoplanin, is involved in metastasis. However, there are currently no ways of testing potential human therapeutics in in vivo models of tumour metastasis or thrombosis. Furthermore, there is clear data that mouse CLEC-2 can be immunodepleted in vivo but it is unknown whether this is also possible with human CLEC-2.
Aims: We aimed to generate a humanised CLEC-2 (hCLEC-2KI) mouse model in which receptor depletion and potential therapeutics could be tested in vivo.
Methods: The extracellular domain of murine CLEC-2 was replaced with the human variant and the mice, as well as their platelets, characterised in vitro and in vivo. CLEC-2 regulation was assessed using the anti-hCLEC-2 monoclonal antibody AYP1.
Results: hCLEC-2KI mice were viable, fertile and born at Mendelian ratio, without evidence of blood-lymphatic mixing. Based on flow cytometric analyses, CLEC-2 surface expression was comparable on wildtype and hCLEC-2KI murine platelets but roughly two times higher than for human platelets. Expression of other platelet glycoprotein receptors was also unaltered, and platelet activation responses were normal except for a slight delay with rhodocytin. Furthermore, platelet spreading on fibrinogen was also unaltered whereas spreading was reduced on mouse podoplanin compared to wildtypes. Together these data suggest that only subtle differences exist between mouse and human CLEC-2. AYP1 treatment induced a transient thrombocytopenia and CLEC-2 downregulation in hCLEC-2KI but not wildtype mice.
Conclusions: We have generated a humanised mouse model in which potential anti-human CLEC-2 biologics can be tested in vivo. Furthermore, we have shown that human, like mouse CLEC-2 can be immunodepleted which could be a potential therapeutic intervention.
To cite this abstract in AMA style:Brown H, Navarro S, Di Y, Thomas S, Watson S, Nieswandt B, Stegner D. A Humanised CLEC-2 Mouse Model to Study Anti-Human CLEC-2 Biologics in vivo [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/a-humanised-clec-2-mouse-model-to-study-anti-human-clec-2-biologics-in-vivo/. Accessed May 18, 2021.
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