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Human recombinant tissue-factor pathway inhibitor prevents the proliferation of cultured human neonatal aortic smooth
Y Kamikubo1, Y Nakahara, S Takemoto
1The Chemo-Sero-Therapeutic Research Institute, Kumamoto City, Japan. VYG07346@niftyserve.or.jp
Abstract:
Tissue-factor pathway inhibitor (TFPI) inhibits the procoagulant activity of the tissue-factor/factor VIIa complex. It was recently reported that TFPI prevented restenosis following tissue injury in a rabbit atherosclerotic model. In order to clarify the mechanism behind this successful prevention of restenosis, we investigated the direct effect of human recombinant TFPI (h-rTFPI) on the proliferation of cultured human neonatal aortic smooth muscle cells (hSMC). We found that h-rTFPI exhibits inhibitory activity toward hSMC proliferation, while h-rTFPI-C which lacks the carboxyl (C)-terminal region does not. Furthermore, we found that h-rTFPI binds to hSMCs with K(d) = 526 nM but that this binding is inhibited by the addition of the synthetic C-terminal peptide, Lys254-Met276, to h-rTFPI. Thus, the interaction of h-rTFPI with hSMCs mediated via the C-terminal region is responsible for the anti-proliferative action of h-rTFPI. On the basis of these results, we presume that the anti-proliferative effect of h-rTFPI in addition to its anticoagulant function plays a significant role in preventing restenosis following tissue injury.
Insights
Tissue-factor pathway inhibitor (TFPI) prevents restenosis by inhibiting smooth muscle cell proliferation. Its C-terminal region is crucial for this anti-proliferative action and binding to these cells.
Area of Science:
- Cardiovascular Biology
- Vascular Biology
- Pharmacology
Background:
- Tissue-factor pathway inhibitor (TFPI) is known to inhibit the tissue-factor/factor VIIa complex, a key component of the coagulation cascade.
- Previous studies suggest TFPI can prevent restenosis in animal models, but the underlying mechanism requires further elucidation.
Purpose of the Study:
- To investigate the direct effect of human recombinant TFPI (h-rTFPI) on the proliferation of human aortic smooth muscle cells (hSMCs).
- To determine the role of the C-terminal region of TFPI in its anti-proliferative activity and cell binding.
Main Methods:
- Cultured human neonatal aortic smooth muscle cells (hSMCs) were treated with h-rTFPI and a truncated version (h-rTFPI-C).
- Cell proliferation was assessed, and binding affinity of h-rTFPI to hSMCs was measured using radioligand assays.
- The effect of a synthetic C-terminal peptide on h-rTFPI binding was evaluated.
Main Results:
- h-rTFPI significantly inhibited hSMC proliferation, whereas h-rTFPI-C did not show this effect.
- h-rTFPI demonstrated binding to hSMCs with a dissociation constant (Kd) of 526 nM.
- A synthetic C-terminal peptide (Lys254-Met276) inhibited the binding of h-rTFPI to hSMCs, indicating the C-terminus mediates this interaction.
Conclusions:
- The anti-proliferative effect of h-rTFPI on hSMCs is mediated by its C-terminal region.
- Binding of h-rTFPI to hSMCs via its C-terminus is responsible for its anti-proliferative action.
- TFPI's anti-proliferative activity, in addition to its anticoagulant properties, likely contributes to preventing restenosis after tissue injury.