Facing the challenges of antiviral CRISPR-Cas13 COVID-19 therapy in South America

NÚÑEZ PEDROZO CRISTIAN NAHUEL; GHIRINGHELLI PD; PERALTA TOMÁS; GIMENEZ CS; CUNIBERTI L; BELAICH MARIANO NICOLÁS; OLEA FD

Buenos Aires

Congreso; Reunión de las Sociedades de Biociencias 2020; 2020

Sociedad Argentina de Investigación Clínica

Introduction. CRISPR technology has generated great expectation in the feld of gene editing. Since March 2020, Stanford?s laboratory has become a world referent by offering an antiviral therapy. Up to date COVID-19 continues spreading relentless worldwide, mainly over winter time of the southern hemisphere. During this time, the virus has undergone mutations with uncertain impact on the effcacy of the crRNAs originally designed by Abbott. Our aim is to analyze the performance of Stanford?s crRNAs in 905 SARS-COV-2 South American Genomic Sequences (SAGS).Methodology. The top 40 crRNAs targeting the conserved RdRP and N regions of SARS-COV-2 RefSeq selected by Abbott were used for alignment studies with the SAGS published until September 2020 in GISAID. The bioinformatics tools Bowtie, MAFFT, Jalview and Cas13design were used for aligning and analyzing crRNAs to SAGS with a criterion of maximum complementarity (-v 0) and fast progressing method (FFT-NS-2).Results. The clade distribution analysis of the SAGS revealed the main contribution of GR (53%), G (24%), GH (15%) in accordance to GISAD. The alignment of crRNAs to SAGS resulted in 4 out of 40 crRNA (10%) presenting an alignment effciency lower than the 99% cutoff. These 4 crRNAs originated 269 misalignments mainly on sequences from Brazil (74%), Peru (10%) and Chile (8%). Misaligned Brazilian sequences had a distinctive mutation (T29148C). The Cas13design analysis predicted a high effcacy score for 2 of the 4 crRNAs (Q4-Q3) and low for the remaining 2 (Q2-Q1). Conclusion. The evolution of the SARS-COV-2 clades in South America diverged from the scenario predicted in January 2020 in the Northern Hemisphere. However, the projected impact represents only a 1% loss of effcacy, the T29148C mutation circulating in Brazil being the main cause of misalignment in that country. Therefore, the combination of several crRNAs consolidates as the global antiviral CRISPR-based therapeutic strategy.