Soluble ACE2 (sACE2) decoy receptors are promising agents to inhibit SARS-CoV-2, as their efficiency is less likely to be affected by common escape mutations in viral proteins. However, their success may be limited by their relatively poor potency. To address this challenge, we developed a large decoy library of sACE2 fusion proteins, generated with several protease inhibitors or multimerization tags. Among these decoys, multimeric sACE2 consisting of SunTag or MoonTag systems, which were originally utilized for signal amplification or gene activation systems, were extremely effective in neutralizing SARS-CoV-2 in pseudoviral systems and in clinical isolates. These novel sACE2 fusion proteins exhibited greater than 100-fold SARS-CoV-2 neutralization efficiency, compared to monomeric sACE2. SunTag or MoonTag in combination with a more potent version of sACE2, which has multiple point mutations for greater binding (v1), achieved near complete neutralization at a sub-nanomolar range, comparable with clinical monoclonal antibodies. Pseudoviruses bearing mutant versions of Spike, alpha, beta, gamma or delta variants, were also neutralized efficiently with SunTag or MoonTag fused sACE2(v1). Finally, therapeutic treatment of sACE2(v1)-MoonTag provided protection against SARS-CoV-2 infection in an in vivo mouse model. Overall, we suggest that the superior activity of the sACE2-SunTag or sACE2-MoonTag fusions is due to the greater occupancy of the multimeric sACE2 receptors on Spike protein as compared to monomeric sACE2. Therefore, these highly potent multimeric sACE2 decoy receptors may offer a promising treatment approach against SARS-CoV-2 infections.

中文翻译：

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基于蛋白质支架的可溶性 ACE2 多聚化在体外和体内有效阻断 SARS-CoV-2 感染

可溶性 ACE2 (sACE2) 诱饵受体是抑制 SARS-CoV-2 的有前途的药剂，因为它们的效率不太可能受到病毒蛋白中常见逃逸突变的影响。然而，它们的成功可能受到其相对较差的效力的限制。为了应对这一挑战，我们开发了一个大型 sACE2 融合蛋白诱饵文库，由多种蛋白酶抑制剂或多聚化标签生成。在这些诱饵中，由 SunTag 或 MoonTag 系统组成的多聚体 sACE2 最初用于信号放大或基因激活系统，在中和假病毒系统和临床分离株中的 SARS-CoV-2 方面极为有效。与单体 sACE2 相比，这些新型 sACE2 融合蛋白表现出超过 100 倍的 SARS-CoV-2 中和效率。SunTag 或 MoonTag 与更有效的 sACE2 版本相结合，sACE2 具有多个点突变以实现更大的结合 (v1)，在亚纳摩尔范围内实现了近乎完全的中和，可与临床单克隆抗体相媲美。带有突变版本的 Spike、alpha、beta、gamma 或 delta 变体的假病毒也被 SunTag 或 MoonTag 融合的 sACE2(v1) 有效中和。最后，sACE2(v1)-MoonTag 的治疗提供了针对 SARS-CoV-2 感染的保护。体内小鼠模型。总体而言，我们认为 sACE2-SunTag 或 sACE2-MoonTag 融合体的优异活性是由于与单体 sACE2 相比，多聚体 sACE2 受体在 Spike 蛋白上的占有率更高。因此，这些高效的多聚体 sACE2 诱饵受体可能为 SARS-CoV-2 感染提供一种有前景的治疗方法。