A Sendai Virus-Based Cytoplasmic RNA Vector as a Novel Platform for Long-Term Expression of MicroRNAs

Cytoplasmic RNA virus-derived vectors have emerged as attractive vehicles for microRNA (miRNA) delivery as they possess no potential risk of chromosomal insertion. However, their relatively short-term expression limits their use in biological applications that require long-term miRNA manipulation, such as somatic cell reprogramming. Here, we show that a cytoplasmic RNA virus vector based on a replication-defective and persistent Sendai virus (SeVdp) serves as an effective platform for long-term production of miRNAs capable of inducing sequence-specific target suppression. The SeVdp vector was able to simultaneously deliver embryonic stem cell-enriched miRNAs, as well as multiple transcription factors, into fibroblasts, resulting in effective reprogramming into induced pluripotent stem cells. Furthermore, we report that the murine miR-367 hairpin produced elevated levels of mature miRNA when it was incorporated into the SeVdp vector and served as an effective backbone for production of artificial miRNAs. These SeVdp vector-derived artificial miRNAs efficiently inhibited expression of target genes. Our findings provide novel insights into a powerful tool for long-term and targeted gene silencing in areas such as regenerative medicine, gene therapy, and cell therapy.