NMNAT3 improves mitochondrial function and enhances BMSCs anti-oxidative stress through the NAD+-Sirt3 pathway

Background To investigate the effects of NMNAT3 on mitochondrial function and anti-oxidative stress in rabbit BMSCs and its underlying mechanisms. Methods Stable strains of NMNAT3 overexpressing rabbit BMSCs were obtained by lentivirus transfection; the Oxidative stress model in rabbit BMSCs was imitated by treating with H 2 O 2 ; Observe the changes in mitochondrial ultrastructure and mitochondrial function-related indicators (mitochondrial membrane potential, ATP and mitochondrial protein PGC-1α, NRF1 synthesis), to study the effect of NMNAT3 on improving mitochondrial function under oxidative stress; detect ROS and lipids Peroxidation products (MDA content), antioxidant enzymes (CAT and GPx) activity, SA-β-Gal activity and apoptosis in rabbit BMSCs, to study the changes of the anti-oxidative stress ability of BMSCs modified by NMNAT3;Then, the selective Sirt3 inhibitor (3-TYP) was used to analyze the mechanism of NMNAT3 improve mitochondrial function and antioxidant stress ability of BMSCs by regulating mitochondrial NAD + levels, and whether it affects the acetylation levels of mitochondrial target proteins (Idh2 and FOXO3a) and the expression and activation of effect proteins (GSH, ATP synthase and Mn-SOD) through Sirt3 pathway. Results Overexpression of NMNAT3 can improve the mitochondrial ultrastructural damage of rabbit BMSCs under oxidative stress; increase the mitochondrial membrane potential, increase the synthesis of ATP and mitochondrial protein PGC-1α and NRF1,significantly improve the function of mitochondria.It also can significantly enhance the antioxidant stress ability of rabbit BMSCs by reducing ROS level and MDA content, increasing the activities of antioxidant enzymes CAT and GPx, and decreasing cell senescence and apoptosis under stress.Rabbit BMSCs overexpressed by NMNAT3 significantly increased the activity of Sirt3, significantly decreased the acetylation levels of Idh2 and FOXO3a under oxidative stress, and increased the level of GSH and the activities of ATP synthase and Mn-SOD.However, the addition of 3-TYP basically blocked the protective effect of NMNAT3, indicating that Sirt3 is an important pathway for NMNAT3 to regulate mitochondrial function and antioxidant stress in BMSCs under oxidative stress. Conclusion NMNAT3 can effectively improve the mitochondrial function of rabbit BMSCs under oxidative stress through NAD + -Sirt3 pathway, and play a role in enhancing its antioxidant stress injury.