Sustained depletion of FXIII-A by inducing acquired FXIII-B deficiency

Abstract

The activated form of coagulation factor XIII (FXIII-A2B2), FXIII-A*, is a hemostatic enzyme essential for inhibiting fibrinolysis by irreversibly crosslinking fibrin and antifibrinolytic proteins. Despite its importance, there are no modulatory therapeutics. Guided by the observation that humans deficient in FXIII-B have reduced FXIII-A without severe bleeding, we hypothesized that a suitable small interfering RNA (siRNA) targeting hepatic FXIII-B could safely decrease FXIII-A. Here we show that knockdown of FXIII-B with siRNA in mice and rabbits using lipid nanoparticles resulted in a sustained and controlled decrease in FXIII-A. The concentration of FXIII-A in plasma was reduced by 90% for weeks after a single injection and for more than 5 months with repeated injections, whereas the concentration of FXIII-A in platelets was unchanged. Ex vivo, crosslinking of α2-antiplasmin and fibrin was impaired and fibrinolysis was enhanced. In vivo, reperfusion of carotid artery thrombotic occlusion was also enhanced. Re-bleeding events were increased after challenge, but blood loss was not significantly increased. This approach, which mimics congenital FXIII-B deficiency, provides a potential pharmacologic and experimental tool to modulate FXIII-A2B2 activity.

Fibrin is a critical regulator of neutrophil effector function at the oral mucosal barrier

“…siRNA-LNP preparation and analysis siFbg or control siRNA targeting Luciferase (siLuc), purchased from Integrated DNA Technologies (Coralville, IA), were encapsulated in lipid nanoparticles (LNPs) and analyzed as previously described (56,57). These LNPs naturally accumulate in the liver and are up taken into hepatocytes (58), where fibrinogen is made.…”

Aortic intimal resident macrophages are essential for maintenance of the non-thrombogenic intravascular state

“…Mice were injected with either siFibrinogen or an siRNA targeting luciferase (siLuciferase, control) at 1 mg siRNA per kg body weight via tail vein injection. siFibrinogen and siLuciferase were each encapsulated in lipid nanoparticles, composed of an ionizable lipid (DLin-MC3-DMA), phosphatidylcholine, cholesterol and a polyethylene glycol lipid, using methods previously described 56 . To determine knockdown efficiency, we quantified fibrinogen protein levels in plasma 7 d after injection.…”

Factor XIII-A: An Indispensable “Factor” in Haemostasis and Wound Healing

“…ZED3197 has a Michael acceptor warhead which irreversibly blocks the active site cysteine and has recently been shown to restore blood flow in an in vivo rabbit model of venous stasis without affecting clotting time [217]. An alternative strategy to the peptidic inhibitors is siRNA targeting of FXIII-B which causes a depletion of plasma FXIII-A, without altering platelet FXIII-A and has been shown to enhance fibrinolysis [218]. Clearly, the crucial role that FXIII-A plays in haemostasis spotlights this enzyme as a potential target for antithrombotic strategies.…”