Impact of NF-κB pathway on the intervertebral disc inflammation and degeneration induced by over-mechanical stretching stress.

BACKGROUND: Intervertebral disk degeneration (IVDD) contributes to low back pain. Increased cell apoptosis and inflammation, decreased extracellular matrix are associated with IVDD. Nuclear factor-kappa B (NF-κB) signaling pathway and inflammatory cytokines are implicated in the pathophysiology of IVDD. METHODS: In present study, we established a mechanical stretching stress-stimulated nucleus pulposus (NP) cell model. We knocked down NF-κB p65 by siRNA transfection to inhibit NF-κB and evaluated the effects of NF-κB inhibition on intervertebral disk degeneration. We applied the mechanical stretching stress on NP cells and inhibited NF-κB by siRNA, then evaluated the expression of inflammatory cytokines, matrix metalloproteinase (MMP), aggrecan, collagen II, and monitored viability and apoptosis of NP cells. RESULTS: Mechanical stretching stress induced the expression of TNF-α, IL-1ß, NF-κB, MMP-3 and MMP-13, while inhibited the production of aggrecan and collagen II in NP cells. Mechanical stretching stress decreased the cell viability and induced apoptosis in NP cells. Inhibition of NF-κB by siRNA suppressed the production of TNF-α, IL-1ß, NF-κB, MMP-3 and MMP-13, while upregulated the expression of aggrecan and collagen II in NP cells. CONCLUSIONS: Inhibition of NF-κB by knocking down p65 suppressed over-mechanical stretching stress-induced cell apoptosis and promoted viability in NP cell. Inhibition of NF-κB suppressed inflammation and degeneration of NP cells in IVDD.

Suppression of miR-203-3p inhibits lipopolysaccharide induced human intervertebral disc inflammation and degeneration through upregulating estrogen receptor α.

Accumulating evidence demonstrates that estrogen receptor α (ERα) and microRNAs (miRNAs) play crucial roles in intervertebral disc degeneration (IDD). However, the specific miRNA that related with ERα during IDD development remains unknown. Therefore, we aimed to explore the role of ERα-related miRNA in the IDD model. Nucleus pulposus (NP) cells were isolated from IDD patients. ERα-related miRNAs were selected and verified in NP tissues from IDD patients using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Also, the related cytokine mRNA levels were detected by qRT-PCR. Protein levels were determined by Western blot. The concentrations of inflammatory cytokines in culture supernatants were detected by enzyme-linked immunosorbent assay. MiR-203-3p was found to be upregulated in NP tissues of high-grade IDD patients compared with low-grade IDD patients, and negatively associated with ERα expression. MiR-203-3p directly targeted ERα in NP cells of IDD patients. After lipopolysaccharides (LPS) stimulation, miR-203-3p expression increased, while ERα expression decreased in NP cells. MiR-203-3p inhibition suppressed the effect of LPS on ERα expression and IDD related genes, while ERα downregulation rescued the effect of LPS. In conclusion, suppression the expression of miR-203-3p could inhibit LPS-induced human intervertebral disc inflammation and degeneration through upregulating ERα.