Chemically modified guide RNAs enhance CRISPR-Cas13 knockdown in human cells

Area of Science:

• Molecular Biology
• Gene Editing Technologies
• RNA Therapeutics

Background:

• CRISPR-Cas13 systems offer RNA targeting for gene expression modulation.
• Transient knockdown due to rapid CRISPR RNA (crRNA) degradation limits efficiency in human cells.
• Efficient delivery of Cas13 and crRNA remains a challenge.

Purpose of the Study:

• To identify synthetic RNA modifications that enhance the efficiency and half-life of crRNAs for RNA targeting in human cells.
• To evaluate the efficacy of modified crRNAs and Cas13 in ribonucleoprotein (RNP) complexes for gene expression modulation.
• To establish a non-genetic method for transcript modulation in primary T cells.

Main Methods:

• Chemical RNA modifications were introduced at various positions in synthetic crRNAs.
• Modified crRNAs were co-delivered with recombinant Cas13 enzyme as ribonucleoprotein (RNP) complexes.
• Gene expression modulation was assessed in primary CD4+ and CD8+ T cells.

Main Results:

• Several chemical RNA modifications significantly improved RNA targeting efficiency and crRNA half-life in human cells.
• Co-delivery of modified crRNAs and Cas13 in RNP complexes effectively altered gene expression.
• The system demonstrated robust and efficient transcript modulation in primary T cells without genetic manipulation.

Conclusions:

• Synthetic RNA modifications are effective in stabilizing crRNAs and enhancing CRISPR-Cas13 targeting efficiency.
• CRISPR-Cas13 RNP complexes with modified crRNAs provide a powerful tool for transient gene modulation.
• This approach offers a versatile, non-genetic strategy for manipulating gene expression in immune cells.