Potent anti-SARS-CoV-2 activity by the natural product gallinamide A and analogues via inhibition of cathepsin L

ABSTRACT: The emergence of SARS-CoV-2 in late 2019, and the subsequent COVID-19 pandemic, has led to substantial mortality together with mass global disruption. There is an urgent need for novel antiviral drugs for therapeutic or prophylactic application. Cathepsin L is a key host cysteine protease utilized by coronaviruses for cell entry and is recognized as a promising drug target. The marine natural product, gallinamide A and several synthetic analogues, were identified as potent inhibitors of cathepsin L activity with IC50 values in the picomolar range. Lead molecules possessed selectivity over cathepsin B and other related human cathepsin proteases and did not exhibit inhibitory activity against viral proteases Mpro and PLpro. We demonstrate that gallinamide A directly interacts with cathepsin L in cells, and together with two lead analogues potently inhibits SARS-CoV-2 infection in vitro, with EC50 values in the nanomolar range. However, in an in vivo mouse model of infection, gallinamide A did not reduce viral load in the lung tissue, possibly due to compensatory viral entry mechanisms. In support of this, in TMPRSS2-overexpressing cells gallinamide A had reduced anti-viral activity, but when combined with a TMPRSS2 inhibitor synergistically improved inhibition of viral entry. The data highlights the potential of cathepsin L as a COVID-19 antiviral drug target, and the likely necessity to inhibit multiple routes of viral entry routes to achieve therapeutic efficacy.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Travis Ruan  

LAB HEAD: Mark Larance

PROVIDER: PXD027300 | Pride | 2022-02-17

REPOSITORIES: Pride