OCT4-driven PER1 activation promotes odontogenic differentiation in senescent SCAP spheres.

Mesenchymal stem cells (MSCs) hold significant promise for applications in regenerative medicine, yet their therapeutic potential is often limited by replicative senescence. Identifying effective strategies to reverse replicative senescence in MSCs and elucidating the underlying molecular mechanisms are essential steps in advancing their clinical use. Here, this study demonstrated that the pluripotency regulator octamer-binding transcription factor 4 (OCT4) promoted odontogenic differentiation by activating period circadian regulator 1 (PER1) in replicative senescent stem cells from apical papilla (SCAP) spheres. Specifically, OCT4 overexpression significantly alleviated cell cycle arrest, reduced senescence-associated β-galactosidase activity, and downregulated the expression of senescence-related markers, including CDKN2A/P16, CDKN1A/P21, and TP53/P53. Moreover, this approach markedly enhanced the proliferation and odontogenic differentiation potential of SCAP spheres in vitro and promoted the formation of regenerative pulp-like tissue in vivo. Mechanistically, we demonstrated that OCT4 transcriptionally activated PER1 through direct binding to its promoter, thereby restoring the odontogenic differentiation capacity of replicative senescent SCAP. Collectively, our findings establish the OCT4-PER1 axis as a critical regulatory pathway that counteracts replicative senescence in SCAP. These insights suggest new therapeutic strategies targeting senescence-associated signaling pathways to enhance MSC-based regenerative outcomes.