Interleukin-1 inhibits Sox9 and collagen type Ⅱ expression via nuclear factor-κB in the cultured human intervertebral disc cells

Background The most significant biological change in intervertebral disc degeneration is the decrease of chondrocyte specific gene and protein expression of Sox9 and collagen type Ⅱ. Interleukin-1 （IL-1） is not expressed in the normal intervertebral disc tissue but increases in the degenerated intervertebral disc tissue. This suggests that IL-1 may play a role in regulation of the expression of Sox9 and collagen type Ⅱ. Methods Human intervertebral disc cells were isolated and cultured. Sox9 and collagen type Ⅱ expression during treatment with IL-1, with or without the nuclear factor-κB （NF-κB） activity inhibitor curcumin, were detected by using reverse transcription-polymerase chain reaction （RT-PCR） and Western blotting, and the activity of the NF-κB signaling pathway was detected by the electrophoretic mobility shift assay （EMSA）. Results IL-1 lowered the mRNA level and protein expression of Sox9 and collagen type Ⅱ in the cultured intervertebral disc cells in a dose dependent manner （P 〈0.05）, and this effect was attenuated by curcumin. Curcumin alone had no effect on Sox9 and collagen type Ⅱ expression （P 〉0.05）. IL-1 at concentrations of 0.1 ng/ml, 1 ng/ml and 10 ng/ml could stimulate the activity of NF-κB in the intervertebral disc cells in a dose dependent manner （P 〈0.05） that was inhibited by curcumin. Conclusions We demonstrated the previously unknown function of IL-1 in inhibiting Sox9 and collagen type Ⅱ via NF-κB in the intervertebral disc cells. This inhibition can be attenuated by curcumin, which is an effective NF-κB activity inhibitor.

Adenovirus-mediated TGF-β1 gene transfer to human degenerative lumbar intervertebral disc cells

Objective To test the possibility of modification of human degenerative lumbar disc cells by the exogenous growth factor gene, transforming growth factor β_1 (TGF-β_ 1) cDNA, and the expression of the encoded protein. Methods Nucleus pulposus samples were surgically obtained from 8 patients with degenerat ive lumbar disc disease. The cells were cultured and directly infected by two a denoviral constructs, Ad/CMV-EGFP containing the enhanced green fluorecence pro tein (EGFP) gene (marker gene) and Ad/CMV-TGF-β_1 containing the potentially therapeutic TGF-β_1 gene. Transgene expression was analyzed by fluorescence production and immunohistochemical staining (Ad/CMV-TGF-β_1). Results Culture cells transducted by Ad/CMV-EGFP showed specific green fluorescence und er the fluoroscope and expression sustained for at least 4 weeks. When infe cted by Ad/CMV-TGF-β_1, approximally 30% of cultured cells were staind brown (+) with TGF-β_1 staining. Conclusion This study established the strategy of delivering a potentially therapeutic gene , TGF-β_1, by using an adenoviral vector to human degenerative lumbar interve rtebral disc cells.