Summary
Tissue factor pathway inhibitor (TFPI) is a physiological inhibitor of extrinsic pathway
of coagulation and has biological functions of anticoagulation and anti-inflammation.
Although TFPI has been proved to be a good therapeutic agent of sepsis, inflammatory
shock, and DIC, the clinical application and therapeutic effects of TFPI are impeded
because of its short half-life in vivo. In order to prolong the half-life of TFPI, homology modeling and molecule docking
were performed on a computer workstation principally in protein structural biology
and binding characteristics between TFPI and its receptor LRP (low-density lipoprotein
receptor related protein). Two recombinant long half-life human TFPI mutants coined
TFPI-Mut1 and TFPI-Mut4 were designed and expressed in E.coli. In comparison with the wild-type TFPI, TFPI-Mut1 and TFPI-Mut4 presented a few of
changes in spatial configuration and a decrease in relative Gibbs free energy of docking
complex by 17.3% and 21.5%, respectively, as indicated by a computer simulation. After
refolding and purification, anticoagulant activities, anti-TF/FVIIa and anti-FXa activities
of the mutants were found to be the same as those of wide-type TFPI. The pharmacokinetics
research indicated that alpha phase half-life (t1/2α) of TFPI-Mut1 and TFPI-Mut4 were
prolonged 1.33-fold and 1.96-fold respectively, beta phase half-life (t1/2 β) of TFPI-Mut1
and TFPI-Mut4 were prolonged 1.62-fold and 4.22-fold respectively. These results suggested
that TFPI-Mut1 and TFPI-Mut4 maintained the bioactivities of wild-type TFPI, prolonged
half-life in vivo simultaneously and were expected for better clinical value and therapeutic
effect.
Keywords
TFPI - half-life - mutants - pharmacokinetics