Abstract
<title>Abstract</title> <p>The derivation of induced mesenchymal stem cells (iMSCs) via induced pluripotent stem cells (iPSCs) represents a compelling strategy to produce standardized, scalable cellular sources for regenerative medicine applications [1,2]. Nevertheless, conventional reprogramming methods predominantly rely on genome-integrating vectors, posing significant safety concerns for clinical translation [3,4]. Circular RNAs (circRNAs), characterized by their covalently closed loop conformation, offer a stable, non-integrating, and highly efficient platform for transient gene expression [5,6]. In this study, we established a circRNA-mediated reprogramming approach to generate induced pluripotent stem cells (iPSCs) from human adipose-derived stem cells (ADSCs). Engineered synthetic circRNAs were delivered into ADSCs via lipid nanoparticle-mediated transfection, yielding integration-free iPSC colonies that exhibited typical pluripotent morphology, expression of core pluripotency markers (OCT4, NANOG), and robust trilineage differentiation potential in vitro [7]. These ADSC-derived iPSCs were subsequently differentiated into MSCs using a xeno-free, serum-free directed differentiation protocol, which significantly streamlined the conventional multi-step process, reduced overall differentiation time, and lowered production costs(for details, refer to patent CN119913096A). The derived iMSCs uniformly expressed canonical MSC surface markers (CD73⁺, CD90⁺, CD105⁺, CD34⁻, CD45⁻, HLA-DR⁻) and retained potent osteogenic, chondrogenic, and adipogenic differentiation capacities. Furthermore, these cells displayed elevated expression of extracellular matrix (ECM) proteins, indicative of enhanced structural and functional properties. Collectively, this circRNA-based, non-integrating strategy enables efficient reprogramming of ADSCs into iPSCs and their subsequent differentiation into iMSCs with augmented functionality. This two-step paradigm offers a safe, scalable, and clinically relevant approach for generating rejuvenated MSCs suitable for advanced cell-based therapeutic and regenerative applications(Fig. 1).</p>