Transient let-7/miR-98 reprograms primed pluripotency to induce naive human PSCs

Naive human pluripotent stem cells (hPSCs) are valuable for modeling early development and enabling regenerative applications, yet resetting from the primed state remains inefficient and mechanistically unclear. We identify an unexpected role for miR-98-5p, a let-7 family microRNA (miRNA) typically linked to differentiation, in promoting naive induction. Using a synthetic mRNA screen containing diverse miRNA-responsive elements, we uncovered miR-98-5p as a potent enhancer of resetting. Single-cell RNA sequencing and targeted perturbations show that miR-98-5p directly represses NR6A1 while transiently activating BMP2/4 signaling, triggering network transitions. These changes destabilize the primed gene-regulatory network and enable acquisition of a naive state. Leveraging this mechanism, we establish a feeder-free, miRNA-based, editing-free protocol that boosts resetting efficiency from <10% to ∼80%. To our knowledge, this is the first demonstration that a let-7 miRNA can drive naive induction by coupling direct target repression with activation of pro-naive signaling, suggesting a generalizable reprogramming principle of transient network destabilization.