Generation of oligodendrocyte precursor-like cells from mouse embryonic fibroblasts using miR-7a mimics

Developing effective strategies to enhance remyelination remains a major therapeutic challenge in demyelinating disorders such as multiple sclerosis (MS). MicroRNAs (miRNAs) have emerged as powerful regulators of cell fate. It has been shown that miR-7a is highly expressed in oligodendrocyte precursor cells (OPCs). This study aimed to investigate whether overexpression of miR-7a can reprogram mouse embryonic fibroblasts (MEFs) into OPC-like cells and oligodendrocytes in vitro.

MEFs were cultured, confirmed by vimentin immunostaining, and transfected with miR-7a mimics using Lipofectamine^TM 3000 or Lipofectamine^TM RNAiMAX reagent. Transfection efficiency was assessed by qRT-PCR analysis of miR-7a expression levels. Cells were then cultured in OPC induction medium and assessed for NG2 expression at 14 and 21 days post-transfection. Differentiation potential was examined by transferring induced cells into oligodendrocyte differentiation medium and analyzing O4 and MBP expression using Immunocytofluorescence.

Lipofectamine^TM RNAiMAX-mediated transfection produced significantly higher miR-7a expression than Lipofectamine^TM 3000, with a clear dose-dependent effect. MEFs transfected with miR-7a (10 and 20 pmol) exhibited NG2-positive cells at both 14 and 21 days, whereas no OPC markers were observed in negative controls or induction medium alone. Furthermore, miR-7a-induced OPC-like cells differentiated into O4⁺ and MBP⁺ oligodendrocytes, confirming their lineage potential.

Overexpression of miR-7a successfully reprogrammed MEFs into OPC-like cells and promoted their differentiation into oligodendrocytes in vitro. These findings establish miR-7a as a potential tool for cell-based reprogramming strategies to generate OPC-like cells, warranting further investigation before translation into in vivo remyelination procedures for MS.