Designing rt-PA Analogs to Release its Trapped Thrombolytic Activity

Abstract

Recombinant tissue-type plasminogen activator (rt-PA, alteplase) is an FDA-approved thrombolytic drug. Designing rt-PA analogs to suppress its inhibition by plasminogen activator inhibitor-1 (PAI-1) without compromising its pharmacological activity has been a continued effort because rt-PA is rapidly inactivated by endogenous PAI-1, leading to the thrombolytic activity of rt-PA being trapped by endogenous PAI-1. Here, incorporating currently available structure of the rt-PA-PAI-1 Michaelis complex structures, this paper uncovers the interstructural biophysics underlying the rt-PA-PAI-1 binding interface, and puts forward a structural biophysical basis for the design of a previously reported rt-PA analogue (T103N, N117Q, KHRR (296-299) AAAA). In addition, this paper proposes a set of rt-PA analogs with lower or higher affinity to PAI-1, including rt-PA (alanine scanning for E_60A, D_189 and R_39), rt-PA (Q60E) and rt-PA (Q60E-F150H-Y151K), towards the release of the trapped thrombolytic activity of rt-PA, and also in the hope that there is still room for the improvement of the efficacy-safety balance of rt-PA in future.