Unintended human messenger RNAs with partial complementarity to short hairpin RNA (shRNA) seed regions

Unintended human messenger RNAs (mRNAs) with partial complementarity to short hairpin RNA (shRNA) seed regions represent a major class of off-target effects in RNA interference (RNAi) technology. These mRNAs are inadvertently silenced when the seed region, comprising nucleotides 2 through 8 of the shRNA-derived guide strand, binds to their 3' untranslated regions (UTRs) with partial complementarity (Jackson et al., 2003; Birmingham et al., 2006). This interaction mimics the natural regulatory mechanism of microRNAs (miRNAs), resulting in unintended translational repression or mRNA degradation. Such off-target silencing can lead to significant cellular toxicity, altered experimental phenotypes, and safety risks in clinical applications, most notably hepatotoxicity (Grimm et al., 2006). In the context of drug development, these interactions are a primary hurdle, necessitating rigorous bioinformatic screening and chemical modifications to the RNA backbone to enhance specificity. Furthermore, high levels of shRNA expression can saturate the endogenous RNAi machinery, such as Exportin-5 and the RNA-induced silencing complex (RISC), which compounds the toxic effects (Grimm et al., 2006). Consequently, identifying and avoiding these unintended mRNA interactions is essential for the design of safe and effective RNAi-based therapeutics (Setten et al., 2019). This phenomenon highlights the importance of sequence specificity beyond the intended target site in the development of nucleic acid-based medicines.

Other names

Seed-mediated off-targetsmiRNA-like off-target effectsRNAi off-targetsshRNA-induced off-target transcriptsSeed-matched off-target mRNAs

Seed-mediated RNA interference (RNAi) involving the binding of the shRNA/siRNA guide strand seed region (nucleotides 2-8) to partially complementary sequences in the 3' UTR of unintended mRNAs, leading to miRNA-like gene silencing (Jackson et al., 2003; Birmingham et al., 2006).