Optimizing Synthetic miRNA Minigene Architecture for Efficient miRNA Hairpin Concatenation and Multi-target Gene Knockdown.

Rousset, Francis; Salmon, Patrick; Bredl, Simon; Cherpin, Ophélie; Coelho, Marta; Myburgh, Renier; Alessandrini, Marco; Perny, Michael; Roccio, Marta; Speck, Roberto F; Senn, Pascal; Krause, Karl Heinz (2019). Optimizing Synthetic miRNA Minigene Architecture for Efficient miRNA Hairpin Concatenation and Multi-target Gene Knockdown. Molecular therapy. Nucleic acids, 14, pp. 351-363. American Society of Gene & Cell Therapy 10.1016/j.omtn.2018.12.004

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Synthetic microRNA (miRNA) minigenes (SMIGs) have a major potential for molecular therapy; however, their optimal architecture still needs to be determined. We have previously optimized the stem structure of miRNA hairpins for efficient gene knockdown. Here, we investigate the overall architecture of SMIGs driven by polymerase II-dependent promoters. When miRNA hairpins were placed directly behind the promoter, gene knockdown was inefficient as compared with constructs containing an intercalated sequence ("spacer"). Spacer sequence was relevant for knockdown efficiency and concatenation potential: GFP-based sequences (even when truncated or including stop codons) were particularly efficient. In contrast, a spacer of similar length based on a CD4 intronic sequence was entirely inefficient. Spacer sequences influenced miRNA steady-state levels without affecting transcript stability. We demonstrate that with an optimized spacer, up to five concatenated hairpins targeting two different genes are efficiently expressed and able to knock down their respective targets. Transplantation of hematopoietic stem cells containing a CCR5 knockdown SMIG demonstrated a sustained in vivo efficacy of our approach. In summary, we have defined features that optimize SMIG efficiency. Based on these results, optimized knockdown of genes of interest, such as the HIV co-receptor CCR5 and the NADPH oxidase subunit p22phox, was achieved.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ear, Nose and Throat Disorders (ENT)

UniBE Contributor:

Roccio, Marta


600 Technology > 610 Medicine & health




American Society of Gene & Cell Therapy




Stefan Weder

Date Deposited:

27 Jan 2020 14:30

Last Modified:

05 Dec 2022 15:35

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

CCR5 NOX3 cochlea hematopoietic stem cells lentivector transduction miRNA miRNA hairpins concatenation multi-target gene knockdown siRNA synthetic miRNA minigene





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