IL-1β increases asporin expression via the NF-κB p65 pathway in nucleus pulposus cells during intervertebral disc degeneration

Sci Rep. 2017 Jun 23;7(1):4112. doi: 10.1038/s41598-017-04384-3.

Abstract

Disc degeneration (DD) is a multifaceted chronic process that alters the structure and function of intervertebral discs. The pathophysiology of degeneration is not completely understood, but the consensus is that changes in genes encoding extracellular matrix (ECM) proteins in the disc are the leading factors contributing to DD. Asporin is an ECM protein that has been shown to be increased in degenerated intervertebral discs, but little is known about how asporin is regulated during DD. In exploring the intricate mechanism, we confirmed that asporin was abundantly increased in patients' degenerated nucleus pulposus. Consistently, the increased asporin expression with degeneration was also proved by rabbit intervertebral disc degeneration (IDD) model. Mechanistically, IL-1β upregulated asporin expression by activating the p65 pathway in human nucleus pulposus cells. Furthermore, p65 mediated asporin expression by binding to -41/-31 bp on asporin promoter. Functionally, asporin was the intermediator of IL-1β-inhibited aggrecan and collagen Π expression and played a negative role in TGF-β-induced aggrecan and collagen Π formation in human nucleus pulposus cells. Therefore, identifying asporin as a negative regulator of aggrecan and collagen Π and elucidating its induction mechanisms in human nucleus pulposus cells provides new insight for asporin induction during IDD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Binding Sites
  • Collagen / metabolism
  • Disease Models, Animal
  • Extracellular Matrix Proteins / genetics*
  • Female
  • Gene Expression Regulation
  • Gene Knockdown Techniques
  • Genes, Reporter
  • Humans
  • Interleukin-1beta / metabolism*
  • Intervertebral Disc Degeneration / diagnostic imaging
  • Intervertebral Disc Degeneration / genetics*
  • Intervertebral Disc Degeneration / metabolism*
  • Intervertebral Disc Degeneration / pathology
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Nucleus Pulposus / metabolism*
  • Nucleus Pulposus / pathology
  • Protein Binding
  • Rabbits
  • Signal Transduction*
  • Transcription Factor RelA / metabolism*
  • Young Adult

Substances

  • ASPN protein, human
  • Extracellular Matrix Proteins
  • Interleukin-1beta
  • Transcription Factor RelA
  • Collagen