Small interfering RNA (siRNA) delivery into murine bone marrow-derived macrophages by electroporation

Selective gene silencing by RNA interference (RNAi) is a valuable tool for the targeted manipulation of the development and/or function of cells. Using a fluorescein-labeled non-silencing siRNA duplex, we established a protocol for the electroporation of primary mouse macrophages which routinely yielded > 95% transfected cells. Electroporation of siRNAs directed against MAPK1 and CD86 led to an efficient knock-down of cellular protein in bone marrow-derived mouse macrophages (BM-Mϕ). Importantly, the electroporation procedure did not impair the viability of BM-Mϕ, their ability to ingest or degrade E. coli or their capacity to express iNOS mRNA, to produce NO or to upregulate TNF and IL-6 mRNA in response to inflammatory stimuli such as LPS. Therefore, we propose that electroporation of silencing siRNAs into murine BM-Mϕ is a highly efficient method to manipulate gene expression of BM-Mϕ that does not cause toxicity or a non-specific alteration of macrophage biology.