Suppressing the NHEJ pathway by DNA-PKcs inhibitor NU7026 prevents degradation of HBV cccDNA cleaved by CRISPR/Cas9.

Chronic hepatitis B is a severe liver disease caused by hepatitis B virus (HBV) infection. Covalently closed circular DNA (cccDNA), a super-spiralized, double-stranded form of the HBV genome, is the major determinant of viral persistence. CRISPR/Cas9 nucleases have been recently shown to introduce double-stranded DNA breaks into HBV cccDNA.

Orthologous CRISPR/Cas9 systems for specific and efficient degradation of covalently closed circular DNA of hepatitis B virus.

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the major cause of viral persistence and chronic hepatitis B. CRISPR/Cas9 nucleases can specifically target HBV cccDNA for decay, but off-target effects of nucleases in the human genome limit their clinical utility. CRISPR/Cas9 systems from four different species were co-expressed in cell lines with guide RNAs targeting conserved regions of the HBV genome.