2',3' cyclic-nucleotide 3'-phosphodiesterase (CNP) inhibits SARS-CoV-2 virion assembly by blocking infection-induced mitochondria depolarization.

The COVID-19 pandemic has claimed over 6.5 million lives worldwide and continues to have lasting impacts on the world's healthcare and economic systems. Several approved and emergency authorized therapeutics that inhibit early stages of the virus replication cycle have been developed however, effective late-stage therapeutical targets have yet to be identified. To that end, our lab identified 2',3' cyclic-nucleotide 3'-phosphodiesterase (CNP) as a late-stage inhibitor of SARS-CoV-2 replication. We show that CNP inhibits the generation of new SARS-CoV-2 virions, reducing intracellular titers by over 10-fold without inhibiting viral structural protein translation. Additionally, we show that targeting of CNP to mitochondria is necessary for inhibition, implicating CNP's proposed role as an inhibitor of the mitochondrial permeabilization transition pore as the mechanism of virion assembly inhibition. We also demonstrate that adenovirus transduction of a dually over-expressing virus expressing human ACE2, in cis with either CNP or eGFP inhibits SARS-CoV-2 titers to undetectable levels in lungs of mice. Collectively, this work shows the potential of CNP to be a new SARS-CoV-2 antiviral target.