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Polygonatum sibiricum polysaccharide attenuates BMSC senescence by inhibiting NCOA4-mediated ferritinophagy
Xing Dai1,2, Linhua Wang2, Yu Sun2
1School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, China.
Context:
BMSC senescence is associated with osteoporosis progression. Polygonatum sibiricum polysaccharide (PSP) shows potential anti-senescence activity, but its effects on bone marrow mesenchymal stem cells (BMSCs) remain unclear.
Objective:
To investigate the protective effects and molecular mechanisms of PSP against tert-butyl hydroperoxide (TBH)-induced senescence in BMSCs.
Materials And Methods:
Senescence was induced in primary rat BMSCs with TBH, followed by PSP intervention. Viability was assessed using the Cell Counting Kit-8 assay, while senescence-associated β-galactosidase, alkaline phosphatase, and Oil Red O staining assessed senescence and osteogenic/adipogenic differentiation. Ferritinophagy-associated proteins (NCOA4, FTH1, and LC3) and intracellular Fe2+ were quantified using western blot, immunofluorescence, and FerroOrange staining. Mitochondrial function was evaluated using MitoSOX and JC-1 assays and ATP quantification. Cytosolic mtDNA accumulation and the cGAS-STING pathway were assessed using immunofluorescence colocalization, quantitative polymerase chain reaction, and Western blotting. NCOA4 involvement was examined using an NCOA4-overexpressing lentiviral vector.
Results:
PSP concentration-dependently attenuated TBH-induced senescence phenotypes in BMSCs, partially restored osteogenic differentiation, and reduced adipogenic differentiation. PSP downregulated NCOA4 expression, attenuating ferritinophagy-associated changes and intracellular Fe2+ accumulation. Reduced Fe2+ accumulation preserved mitochondrial membrane potential, reduced mitochondrial reactive oxygen species generation, and reduced cytosolic mtDNA accumulation, alongside attenuated cGAS-STING signaling. Lentiviral overexpression of NCOA4 attenuated the protective effects of PSP on mitochondrial homeostasis and cGAS-STING pathway suppression.
Discussion And Conclusions:
PSP may attenuate BMSC senescence by suppressing NCOA4-mediated ferritinophagy, thereby preserving mitochondrial homeostasis and inhibiting cGAS-STING signaling. These findings provide a rationale for further investigation of PSP as a potential therapeutic strategy for osteoporosis-associated BMSC dysfunction.