A biologically stable DNAzyme that efficiently silences gene expression in cells

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• RNA-cleaving DNA enzymes (DNAzymes) have therapeutic potential for gene silencing but face challenges with low clinical efficacy.
• Previous DNAzyme designs, like the 10-23 enzyme, suffered from product inhibition, limiting their effectiveness.

Purpose of the Study:

• To develop a modified DNAzyme with enhanced activity and stability for therapeutic gene silencing.
• To overcome product inhibition and nuclease degradation issues inherent in classic DNAzyme designs.

Main Methods:

• Engineered a xeno-nucleic-acid-modified DNAzyme (X10-23) incorporating DNA, 2'-fluoroarabino nucleic acid, and α-L-threofuranosyl nucleic acid backbones.
• Assessed multiple-turnover activity under cellular conditions and resistance to nuclease digestion.
• Evaluated the degradation of exogenous and endogenous messenger RNA transcripts in cultured mammalian cells.

Main Results:

• The X10-23 reagent demonstrated multiple-turnover activity and resistance to nuclease digestion.
• X10-23 effectively overcame product inhibition, a key limitation of prior DNAzyme designs.
• In cultured mammalian cells, X10-23 achieved persistent gene silencing by degrading target mRNA transcripts.

Conclusions:

• Novel molecular chemotypes can significantly enhance the activity and stability of DNAzymes.
• The X10-23 DNAzyme represents a promising advancement for nucleic acid-based therapeutics.
• These findings suggest a potential new pathway for nucleic acid enzymes to be translated into clinical applications.