Hemeoxygenase-1 Suppresses IL-1β-Induced Apoptosis Through the NF-κB Pathway in Human Degenerative Nucleus Pulposus Cells

Abstract

Background/Aims: Nucleus pulposus cell (NPC) apoptosis is the main factor in intervertebral disc degeneration (IDD); thus, inhibiting the excessive apoptosis of nucleus pulposus cells may be a potential way to alleviate IDD. The effect of Hemeoxygenase-1 (HO-1) on human NPC apoptosis has never been reported. Our study aimed to investigate the effect and mechanism of HO-1 on apoptosis in human degenerative NPCs. Methods: Nucleus pulposus tissues were collected from patients with lumbar vertebral fracture (LVF) and IDD. The expression of HO-1 and P65 in intervertebral discs was determined using immunohistochemistry and western blot analysis. Apoptosis of human nucleus pulposus cells was quantified by flow cytometric analysis. A recombinant lentiviral vector overexpressing HO-1 and HO-1-siRNA was used to promote or silence the expression of HO-1 in nucleus pulposus cells. The NF-κB inhibitor PDTC was used to inhibit the NF-κB pathway. Results: Our study demonstrated that compared with normal samples, IDD samples showed down-regulation of HO-1 expression and up-regulation of P65 expression. Overexpression of HO-1 inhibited the increase in nucleus pulposus cell apoptosis after IL-1β treatment and simultaneously inhibited the expression of p-P65. Furthermore, after treatment with PDTC, the number of apoptotic cells was significantly decreased with or without overexpression of HO-1. Conclusion: HO-1 might play a significant role in IDD, and HO-1 protected degenerative human NPCs against apoptosis induced by IL-1β through the NF-κB pathway. These findings would aid in the development of novel therapeutic approaches for IDD treatment.

Keywords

• Hemeoxygenase-1
• IL-1β
• Apoptosis
• NF-κB
• Human nucleus pulposus cells