IL-1β induces apoptosis and autophagy via mitochondria pathway in human degenerative nucleus pulposus cells

Sci Rep. 2017 Jan 25:7:41067. doi: 10.1038/srep41067.

Abstract

IL-1β has been reported highly expressed in degenerative intervertebral disc, and our previous study indicated IL-1β facilitates apoptosis of human degenerative nucleus pulposus (NP) cell. However, the underlying molecular mechanism remains unclear. We here demonstrate that IL-1β played a significantly pro-apoptotic effect under serum deprivation. IL-1β decreased Bcl-2/Bax ratio and enhanced cytochrome C released from mitochondria to cytosol, which proved mitochondria-meidated apoptosis was induced. Subsequently, mitochondria damage was detected under IL-1β stimualtion. In addition, IL-1β-mediated injuried mitochondria contributes to activate autophagy. However, pretreatment with the autophagy inhibitor 3-methyladenine showed the potential in further elevating the apoptosis rate induced by IL-1β in NP cells. Our results indicated that the mitochondrial pathway was involved in IL-1β-induced apoptosis of NP cells. Meanwhile, the damaged mitochondria-induced autophagy played a protective role against apoptosis, suggesting a postive feedback mechanism under inflammatory stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Autophagy*
  • Cytochromes c / metabolism
  • Humans
  • Interleukin-1beta / metabolism*
  • Intervertebral Disc Degeneration / pathology*
  • Intervertebral Disc Displacement / pathology*
  • Mitochondria / metabolism*
  • Nucleus Pulposus / pathology*

Substances

  • Interleukin-1beta
  • Cytochromes c

Supplementary concepts

  • Intervertebral disc disease