Pharmaceutical Research

, Volume 28, Issue 12, pp 2996–3015

Subcellular Fate and Off-Target Effects of siRNA, shRNA, and miRNA

Expert Review

DOI: 10.1007/s11095-011-0608-1

Cite this article as:
Singh, S., Narang, A.S. & Mahato, R.I. Pharm Res (2011) 28: 2996. doi:10.1007/s11095-011-0608-1


RNA interference (RNAi) strategies include double-stranded RNA (dsRNA), small interfering RNA (siRNA), short hairpin RNA (shRNA), and microRNA (miRNA). As this is a highly specific technique, efforts have been made to utilize RNAi towards potential knock down of disease-causing genes in a targeted fashion. RNAi has the potential to selectively inhibit gene expression by degrading or blocking the translation of the target mRNA. However, delivering these RNAs to specific cells presents a significant challenge. Some of these challenges result from the necessity of traversing the circulatory system while avoiding kidney filtration, degradation by endonucleases, aggregation with serum proteins, and uptake by phagocytes. Further, non-specific delivery may result in side-effects, including the activation of immune response. We discuss the challenges in the systemic delivery to target cells, cellular uptake, endosomal release and intracellular transport of RNAi drugs and recent progress in overcoming these barriers. We also discuss approaches that increase the specificity and metabolic stability and reduce the off-target effects of RNAi strategy.


cellular uptakeintracellular traffickingmiRNARNA interferenceshRNAsiRNA

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Saurabh Singh
    • 1
  • Ajit S. Narang
    • 2
  • Ram I. Mahato
    • 1
  1. 1.Department of Pharmaceutical SciencesUniversity of Tennessee Health Science CenterMemphisUSA
  2. 2.Bristol-Myers Squibb, Co., Biopharmaceutics R&DNew BrunswickUSA