Blood Science · Nov 5, 2026
Single-episome delivery of BOSMK with miR-142–gated KLF4 streamlines PBMC reprogramming to iPSCs
By Li X, Wen W, Chang JQ et al.
Peripheral blood–derived induced pluripotent stem cells (iPSCs) are attractive for clinical applications, yet multi-plasmid episomal protocols reduce delivery completeness and complicate good manufacturing practice (GMP) workflows. Here, we assembled OCT4, SOX2, MYC, BCL-XL, and KLF4 into a single OriP/EBNA1 episome and tuned KLF4 expression by placing it under the elongation factor 1 alpha (EF1α) promoter with 2 tandem miR-142-3p target sites in its 3′UTR. Across donors, the single-episome system produced robust day-14 colony yields normalized per 1 × 10 ⁵ input cells. A green fluorescent protein (GFP) reporter demonstrated hematopoietic miR-142–dependent suppression, and the miR-gated construct exhibited significantly faster EBNA1 sequence loss by day 4. Resulting iPSC lines expressed TRA-1-60/TRA-1-81, SSEA4, NANOG, and OCT4, maintained normal karyotypes, and generated derivatives of all three germ layers. This miR-142–gated EF1α-KLF4 single-episome streamlines peripheral blood mononuclear cells (PBMCs) reprogramming and provides a GMP-amenable, non-integrating route to high-quality iPSCs.