SDC2 and SDC4 Working Together to Keep the Homeostasis of IVD? A Preliminary Study

Abstract

Introduction Our previous work have proved that Syndecan 4 (SDC4) plays an important role in TNFa and IL1b induced disc degeneration by promoting extracellular matrix degradation, Syndecan 2 (SDC2) and SDC4 both are members of SDC family, however, expression and role of SDC2 in intervertebral disc is still unclear. The role of this study is to investigate the expression pattern and regulation of SDC2 and its and role in intervertebral disc degeneration. Materials and Methods Nucleus pulposus (NP) cells and annulus fibrosis (AF) cells were cultured separately. mRNA were extracted and expression of SDC2 in NP and AF cells were examined by q-PCR method. Expression of SDC2 was examined by q-PCR in 4, 8, 24hs after NP cells were treated by TNFa (20mg/L), IL1-b(10mg/L) and TGF-b (20mg) retrospectively. NP cells were pretreated with p38, JNK and NFkB signaling pathway inhibitors before treatment with TNFa, then expression of SDC2 was examined by qPCR. Results SDC2 was expressed in both NP and AF cells. NP cells have a higher expression level than AF cells of SDC2 in mRNA level. TNFa and IL1b could inhibit SDC2 expression in NP cells robustly. What's more, SDC2 expression was induced after TGFb treatment in NP cells. Inhibition of SDC2 expression by TNFa could be reduced by p38 and NFkB pathway inhibitor. JNK inhibitor has no role in Inhibition of SDC2 expression by TNFa. Conclusion Inflammatory cytokines could inhibit SDC2 expression and induce SDC4 expression in NP cells, p38 and NFkB pathway participant in this process. The different regulation pattern of SDC2 and SDC4 might play important role in keeping intervertebral disc homeostasis. Disclosure of Interest None declared