Rational design of the zonulin inhibitor AT1001 derivatives as potential anti SARS-CoV-2

Although vaccines are greatly mitigating the worldwide pandemic diffusion of SARS-Cov-2, therapeutics should provide many distinct advantages as complementary approach to control the viral spreading. Here, we report the development of new tripeptide derivatives of AT1001 against SARS-CoV-2 Mpro. By molecular modeling, a small compound library was rationally designed and filtered for enzymatic inhibition through FRET assay, leading to the identification of compound 4. X-ray crystallography studies provide insights into its binding mode and confirm the formation of a covalent bond with Mpro C145. In vitro antiviral tests indicate the improvement of biological activity of 4 respect to AT1001. In silico and X-ray crystallography analysis led to 58, showing a promising activity against three SARS-CoV-2 variants and a valuable safety in Vero cells and human embryonic lung fibroblasts. The drug tolerance was also confirmed by in vivo studies, along with pharmacokinetics evalu-ation. In summary, 58 could pave the way to develop a clinical candidate for intranasal administration.

Automated summary

Despite the effectiveness of vaccines in mitigating the spread of SARS-CoV-2, therapeutics offer additional benefits in controlling viral transmission. This study developed tripeptide derivatives targeting SARS-CoV-2 Mpro and identified compound 58 as a promising candidate with improved antiviral activity against variants and safety in vitro and in vivo. These findings suggest the potential of compound 58 for intranasal administration.