Non‑viral transfection methods optimized for miRNA delivery to human dermal fibroblasts

Fibroblasts are beneficial model cells for in vitro studies and are frequently used in tissue engineering. A number of transfection reagents have been employed to deliver microRNAs (miRNAs/miRs) into cells for genetic manipulation. The present study aimed to establish an effective method of transient miRNA mimic transfection into human dermal fibroblasts. The experimental conditions included three different methods: Physical/mechanical nucleofection, and two lipid‑based methods, Viromer^® Blue and INTERFERin^®. To evaluate the impact of these methods, cell viability and cytotoxicity assays were performed. The silencing effect of miR‑302b‑3p was revealed to alter the expression levels of its target gene carnitine O‑octanoyltransferase (CROT) by reverse transcription‑quantitative PCR. The present study showed that all selected non‑viral transient transfection systems exhibited good efficiency. It was also confirmed that nucleofection, for which a 21.4‑fold decrease in the expression of the CROT gene was observed 4 h after 50 nM hsa‑miR‑302b‑3p transfection, was the most effective method. However, these results indicated that lipid‑based reagents can maintain the silencing effect of miRNAs up to 72 h after transfection. In summary, these results indicated that nucleofection may be the optimal method for the transport of small miRNA mimics. However, lipid‑based methods allow for the use of lower concentrations of miRNA and maintain longer‑lasting effects.