GSE183935
Genomic and epigenetics guided identification of tissue-specific genomic safe harbor sites for gene therapy
One common strategy in gene and cell therapies requires the integration and stable transcription of transgenes into the host cell genomes. Genomic safe harbors (GSHs) are regions of the genome that can maintain the expression of transgenes without disrupting the transcriptome of host cells. With recent advances in genome editing technology, GSHs play an increasingly important role in improving the efficiency and safety of genome engineering. However, limited candidate GSHs have been identified. In addition, many parameters currently used to identify GSHs are not knowledge based and none of the current available GSHs meet all the ideal safety requirement. In this study, we use the polymorphic mobile element insertions (pMEIs) that naturally occur among healthy human populations to facilitate GSHs searching. By integrating pMEIs with epigenomic signatures and 3D chromatin organization information, we developed a framework to map cell typespecific GSHs. We applied our framework to pMEIs identified in the 1000 Genomes project and GTEX projects and identified novel GSHs Candidates in blood and brain cells. We further validated that a transgene cassette integrated in one novel GSH can be stably transcribed without affecting normal proliferation and differentiation of host cells. We also developed a user-friendly program to search for GSHs in different population and cell types. Overall design: Candidate Genomic safe harbor sites are predicted using data from the 1000 Genome and GTEx projects. GFP expression cassette was integrated into four (three identified in blood and one in brain)  safe harbor site, and two random site in HUDEP2 cells. RNA-seq assays were performed in all GFP integrated and  wild-type HUDEP2 cells..