The American journal of pathology
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Matrix metalloproteinase-3 (MMP-3) plays an important role in intervertebral disc degeneration, a ubiquitous condition closely linked to low back pain and disability. Elevated expression of syndecan 4, a cell surface heparan sulfate proteoglycan, actively controls disc matrix catabolism. However, the relationship between MMP-3 expression and syndecan 4 in the context of inflammatory disc disease has not been clearly defined. ⋯ Finally, we show that transforming growth factor-β can block the up-regulation of MMP-3 induced by tumor necrosis factor (TNF)-α by counteracting the NF-κB pathway and syndecan 4 expression. Taken together, our results suggest that cooperative signaling through syndecan 4 and the TNF receptor 1-MAPK-NF-κB axis is required for TNF-α-dependent expression of MMP-3 in nucleus pulposus cells. Controlling these pathways may slow the progression of intervertebral disc degeneration and matrix catabolism.