STC1 promotes osteogenic differentiation and represses inflammation via inhibition of NF‑κB signaling in mesenchymal stromal cells.

Abstract

The aging of mesenchymal stromal cells (MSCs) is characterized by impaired osteogenic differentiation and enhanced adipogenic differentiation. Studies have identified stanniocalcin‑1 (STC1) as a core component of the senescence‑associated secretory phenotype and a regulator of osteoblast maturation; however, its role in MSC biology remains poorly understood. In the present study, bone marrow‑derived MSCs were used and in vitro functional assays together with molecular and omics‑based analyses were performed to investigate the role of STC1. It was observed that STC1 expression was upregulated in aged MSCs and during both osteogenic and adipogenic differentiation. Small interfering RNA‑mediated depletion of STC1 reduced cellular senescence and notably impaired osteogenic differentiation, whereas adipogenic and chondrogenic differentiation were not significantly affected. RNA sequencing revealed that STC1 knockdown led to the downregulation of osteogenesis‑related genes and the concomitant upregulation of inflammatory factors. Genes associated with closing differentially accessible regions (DARs) were enriched in osteogenic pathways, whereas those associated with opening DARs were predominantly involved in inflammatory responses. Mechanistically, STC1 knockdown led to the activation of NF‑κB signaling. Pharmacological inhibition assays using NF‑κB inhibitors were performed to validate pathway involvement. Pharmacological inhibition of NF‑κB signaling significantly mitigated the impairment in osteogenic differentiation and attenuated the inflammatory response induced by STC1 depletion. Collectively, these findings suggest that STC1 is involved in the regulation of osteogenic differentiation and inflammatory signaling through the modulation of NF‑κB activity in MSCs. Furthermore, targeting STC1 while inhibiting NF‑κB signaling may represent a promising therapeutic strategy for alleviating MSC dysfunction and age‑related bone loss.