Coculture of stem cells under periodic mechanical stress promotes nucleus pulposus cells proliferation and autophagy

Intervertebral disc degeneration (IDD) is the main cause of low back pain (LBP), and it is caused by the deterioration of the physiological function and structure of the nucleus pulposus. Previous research has separately studied the effects of adipose-derived mesenchymal stem cells (ADSCs) and periodic mechanical stress (PMS) in IDD. However, the synergistic effect of these two on the repair of IDD remains unclear. Therefore, we simulated the effects of periodic mechanical stress co-culture (PMSC) on nucleus pulposus cells (NPCs) by using Transwell chambers and periodic compression device. We found that PMSC can promote the proliferation of NPCs and activate autophagy by activating Integrin alpha1(ITGA1), and rescue the apoptosis of NPCs under inflammatory conditions. To elucidate the mechanism underlying the effects of PMSC, the expression of ITGA1 was inhibited. It was found that PMSC regulates the Src/GIT1/ERK11/2 axis through ITGA1, thus promoting proliferation and inducing autophagy in NPCs.