Blocking endothelial SERPINE1 increased FXIa-mediated cleavage of a chromogenic substrate and enhanced the ability of FXIa to promote fibrin formation in plasma (Puy C et al., 2019). Western blot and immunofluorescence analyses further demonstrated that FXIa:SERPINE1 complexes are either released into the media or trafficked to early and late endosomes, as well as lysosomes, within human umbilical vein endothelial cells (HUVEC) (Puy C et al., 2019). Additionally, circulating FXIa:SERPINE1 complexes were detected using ELISA in a baboon model of Staphylococcus aureus sepsis (Puy C et al., 2019).
These findings suggest that SERPINE1 forms a complex with FXIa on ECs, inhibiting its activity while promoting the clearance and degradation of FXIa.
Puy, C, Ngo, ATP, Pang, J, Keshari, RS, Hagen, MW, Hinds, MT, Gailani, D, Gruber, A, Lupu, F, McCarty, OJT
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