Autophagy activation alleviates annulus fibrosus degeneration via the miR-2355-5p/mTOR pathway

J Orthop Surg Res. 2025 Jan 23;20(1):86. doi: 10.1186/s13018-025-05492-x.

Abstract

Background: Intervertebral disc degeneration disease (IVDD) is a major cause of disability and reduced work productivity worldwide. Annulus fibrosus degeneration is a key contributor to IVDD, yet its mechanisms remain poorly understood. Autophagy, a vital process for cellular homeostasis, involves the lysosomal degradation of cytoplasmic proteins and organelles. This study aimed to investigate the role of autophagy in IVDD using a hydrogen peroxide (H2O2)-induced model of rat annulus fibrosus cells (AFCs).

Methods: AFCs were exposed to H2O2 to model oxidative stress-induced degeneration. Protein expression levels of collagen I, collagen II, MMP3, and MMP13 were quantified. GEO database analysis identified alterations in miR-2355-5p expression, and its regulatory role on the mTOR pathway and autophagy was assessed. Statistical tests were used to evaluate changes in protein expression and pathway activation.

Results: H2O2 exposure reduced collagen I and collagen II expression to approximately 50% of baseline levels, while MMP3 and MMP13 expression increased twofold. Activation of autophagy restored collagen I and II expression and decreased MMP3 and MMP13 levels. GEO analysis revealed significant alterations in miR-2355-5p expression, confirming its role in regulating the mTOR pathway and autophagy.

Conclusions: Autophagy, mediated by the miR-2355-5p/mTOR pathway, plays a protective role in AFCs degeneration. These findings suggest a potential therapeutic target for mitigating IVDD progression.

MeSH terms

  • Animals
  • Annulus Fibrosus* / metabolism
  • Annulus Fibrosus* / pathology
  • Autophagy* / drug effects
  • Autophagy* / genetics
  • Autophagy* / physiology
  • Cells, Cultured
  • Disease Models, Animal
  • Hydrogen Peroxide
  • Intervertebral Disc Degeneration* / genetics
  • Intervertebral Disc Degeneration* / metabolism
  • Intervertebral Disc Degeneration* / pathology
  • Matrix Metalloproteinase 13 / genetics
  • Matrix Metalloproteinase 13 / metabolism
  • Matrix Metalloproteinase 3 / genetics
  • Matrix Metalloproteinase 3 / metabolism
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Oxidative Stress / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / physiology
  • TOR Serine-Threonine Kinases* / metabolism

Substances

  • TOR Serine-Threonine Kinases
  • MicroRNAs
  • mTOR protein, rat
  • Hydrogen Peroxide
  • Matrix Metalloproteinase 13
  • Matrix Metalloproteinase 3