Cross talk between Smad transcription factors and TNF-α in intervertebral disc degeneration

The transforming growth factor-β (TGF-β) and the tumor necrosis factor-α (TNF-α) families are known to play important roles in intervertebral disc degeneration (IVD). However, molecular interactions between the TGF-β and TNF-α signaling pathways have yet to be elucidated. The purpose of this study was to analyze the expression patterns of Smad transcription factor signaling associated with IVDs with aging and to examine the modulation of Smad signaling by TNF-α in IVD cells using SD rats. According to these experimental results, BMP signals in the TGF-β family were more likely to be a key factor in IVD degeneration by aging, and it was predicted that besides the involvement of catabolic factors like MMPs and ADAMS-TS, there may be a decrease in expression of anabolic factors through cross talk of signaling between TNF-α and TGF-β pathway in pathogenesis of disc degeneration.