Indoxyl Sulfate Suppresses Hpdlc Osteogenesis Through Ferroptosis

Human periodontal ligament stem cells (hPDLCs) play pivotal roles in periodontal tissue repair and bone regeneration. This study investigated the inhibitory effects and underlying mechanisms of indoxyl sulfate (IS), a uremic toxin, on the osteogenic differentiation capacity of hPDLCs. The hPDLCs were exposed to varying IS concentrations in osteogenic induction media. Cell proliferation and mineralization were assessed through CCK-8 viability assays, alkaline phosphatase (ALP) activity tests, and alizarin red S staining. Osteogenic markers were quantified via western blotting and reverse transcription-quantitative PCR (qRT-PCR). Ferroptosis-related pathways were systematically analyzed using RNA sequencing, validated through RT-qPCR, western blot, and transmission electron microscopy (TEM). The study protocol was approved by the Institutional Ethics Committee (SH9H-2021-T112-1). The cell viability of hPDLCs was dose-dependently suppressed by IS. Based on the results of transcriptomic and molecular analyses, it revealed IS-mediated dysregulation of the ferroptosis-related SLC7A11-GPX4 axis. IS significantly reduced mineralization capacity (p<0.01), which was partially reversed by the ferroptosis inhibitor. Downregulated ALP activity and decreased RUNX2/BMP2 protein expression under IS exposure were similarly rescued by ferroptosis suppression (p<0.05). IS impairs hPDLCs osteogenesis by activating ferroptosis through the SLC7A11/GPX4 signaling pathway. These findings provide mechanistic insights into CKD-associated alveolar bone deterioration, suggesting ferroptosis modulation as a potential therapeutic target.