Delivery of Designer Epigenome Modifiers into Primary Human T Cells

The development of tools which allow for the precise alterations of the epigenetic landscape in desired genomic locations presents exciting possibilities toward further understanding how gene expression is regulated and opportunities to harness these properties for therapeutic purposes. In contrast to gene knockout strategies, targeted epigenome modifications, such as editing of DNA methylation, can mediate gene expression modulation without changing the genomic sequence. Thereby, in a therapeutic context, this strategy may offer a safer route as compared to gene disruption using designer nucleases that, to reach high efficiencies, relies on the occurrence of random mutations to inactivate the target gene. In addition, therapeutic benefit is influenced not only by the intrinsic safety and efficacy of the tools used but also by methods that allow efficient and non-toxic transfer of the selected reagents in the target cells. Here, we describe a detailed protocol, for safe delivery of TALE-based designer epigenome modifiers in the form of in vitro transcribed mRNA into primary human CD4⁺ T cells to efficiently silence the expression of an exemplary human gene (i.e., CCR5).