Differentiation of bone marrow mesenchymal stem cells into nucleus pulposusk-like cells induced by Nampt/NAD/Sirt1 axis of Achyranthes bidentata Bl. saponins / 中国组织工程研究

ABSTRACT

BACKGROUND: Studies have shown that bone marrow mesenchymal stem cells (BMSCs) can differentiate into nucleus pulposus-like cells, but the mechanism of differentiation is not clear. OBJECTIVE: To induce bone BMSCs into nucleus pulposus-like cells using Achyranthes bidentata Bl. saponins (ABS) and to explore the role of Nampt/NAD/Sirt1 axis in the differentiation of BMSCs. METHODS: BMSCs were collected from Sprague-Dawley rats. Cells at passage 3 were divided into four groups BMSCs group, BMSCs+ABS group, BMSCs+ABS+nicotinamide mononucleotide (an exogenous small molecule substance promoting NAD synthesis) group, BMSCs+ABS+FK866 (nicotinamide phosphoribosyltransferase inhibitor) group, in which the cells were induced for 14 days. Alcian blue staining was used to show the changes of glycosaminoglycan in the cells. RT-PCR was used to detect the mRNA expression of COL2, Aggrecan, KRT19, Pax1. The protein expression level of COL2 was detected by western blot. The activity of Sirt1 was detected by Sirt1 assay kit and the content of NAD+ was measured by NAD+/NADH kit. RESULTS AND CONCLUSION: (1) Compared with the BMSCs group, BMSCs+ABS group showed significant increases in the expression levels of glycosaminoglycan, Aggrecan, KRT19, and Pax1 (P < 0.05), and the protein expression levels of COL2, activity of Sirt1, and content of NAD+ were also significantly increased (all P < 0.05). (2) Compared with the BMSCs+ABS group, the above-mentioned indicators were significantly increased in the BMSCs+ABS+nicotinamide mononucleotide (P < 0.05); on the contrary, these indicators were all decreased significantly in the BMSCs+ABS+FK866 group (P < 0.05). To conclude, ABS could induce the differentiation of rat BMSCs into nucleus pulposus-like cells, in which the Nampt/NAD/Sirt1 axis might play a promotion role.