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Polyethylenimine (PEI)/siRNA-Mediated Gene Knockdown In Vitro and In Vivo

  • Sabrina Höbel
  • Achim Aigner
Protocol
Part of the Methods in Molecular Biology book series (MIMB, volume 623)

Abstract

Since its discovery about 10 years ago, RNA interference (RNAi) has become an almost standard method for the knockdown of any target gene of interest. It is mediated by small interfering RNAs (siRNAs), which trigger a catalytic mechanism for mRNA degradation. Consequently, the delivery of intact siRNA is of critical importance for the induction of RNAi. Due to the physicochemical and biological properties of siRNAs, resulting in high instability and poor cellular uptake, siRNA modifications and pharmaceutical formulations have been used to enhance RNAi efficacy. This is particularly relevant for the in vivo delivery of siRNAs, which still poses a major hurdle for the experimental or therapeutic application of RNAi.

Polyethylenimines (PEIs) are water-soluble, linear, or branched synthetic polymers of variable length with protonable amino groups in every third position. We have shown that certain PEIs are able to form noncovalent complexes with siRNAs, which mediate their protection against nucleolytic degradation as well as enhance their cellular uptake and intracellular release. In this chapter, the preparation and use of PEI/siRNA complexes for various in vitro and in vivo applications are described. Examples for conducting gene targeting experiments and the analysis of knockdown efficacies are given.

Key words

RNA interference Small interfering RNA Polyethylenimine In vivo siRNA delivery Gene knockdown RNAi siRNA PEI 

Notes

Acknowledgments

The authors’ work was supported by grants from the German Cancer Aid (Deutsche Krebshilfe) and the German Research Foundation (Deutsche Forschungsgemeinschaft; AI 24/6-1 and Research Group 627 “Nanohale”).

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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Department of Pharmacology and ToxicologySchool of Medicine, Philipps-UniversityMarburgGermany

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