Development Of Novel Thrombus Inhibitor Targeting Collagen

Arterial thrombosis leads to tissue ischemia and necrosis,which is a serious threat to human health.At present,various antithrombotic drugs have been developed,but mainly targeting at blood platelets and coagulation factors.These drugs may disturb the balance of normal blood coagulation system and thus suffer from the risk of bleeding.In the pre-vious work,a peptide inhibitor,LWWNSYY,was then designed to cover the exposed collagen rather than the blood components.It was proven capable of inhibiting thrombosis.However,hydrophobic groups in LWWNSYY reduced its water-solubility and restricted its application.Therefore,the composition of LWWNSYY was optimized by replacing the hydrophobic amino acid residues by charged amino acid residues.The obtained LERNSTY and LEKNSTY were found with good solubility,as well as good stability in serum.Both LERNSTY and LEKNSTY could effectively bind on collagen with a K_d of1.647±0.303?M and 0.613±0.182?M,respectively.The effective half inhibitory concen-tration(IC₅₀)of 2.73±0.48?g/m L and 2.44±0.32 was obtained for LERNSTY and LEKNSTY,respectively,which were better than that of LWWNSYY.Therefore,effective antithrombotic agents LERNSTY and LEKNSTY were obtained through the introduction of charged amino acid residues.Secondly,the conformation of peptide inhibitors was modified by embedding D-type amino acid and cyclizing.LwWnSyY and LeKnStY?lowercase letter indicates D-amino acid,capital letter indicates L-amino acid?were designed.Further cyclization was per-formed to obtain cyc-Lw WnSyY and cyc-LeKnStY.The results showed that the D-amino acid embedding and the cyclization could enhance the half-life and improve the stability in serum.Therefore,through the rational design of peptide inhibitors,the solubility and stabil-ity in blood serum of thrombus inhibitors were optimized.LEKNSTY and its cyclization form were obtained as efficient thrombus inhibitors,which would facilitate the develop-ment of antithrombotic peptide drugs.