Targeting RPTPσ with lentiviral shRNA promotes neurites outgrowth of cortical neurons and improves functional recovery in a rat spinal cord contusion model

Brain Res. 2014 Oct 24;1586:46-63. doi: 10.1016/j.brainres.2014.08.048. Epub 2014 Aug 21.

Abstract

After spinal cord injury (SCI), the rapidly upregulated chondroitin sulfate proteoglycans (CSPGs), the prominent chemical constituents and main repulsive factors of the glial scar, play an important role in the extremely limited ability to regenerate in adult mammals. Although many methods to overcome the inhibition have been tested, no successful method with clinical feasibility has been devised to date. It was recently discovered that receptor protein tyrosine phosphatase sigma (RPTPσ) is a functional receptor for CSPGs-mediated inhibition. In view of the potential clinical application of RNA interference (RNAi), here we investigated whether silencing RPTPσ via lentivirus-mediated RNA interference can promote axon regeneration and functional recovery after SCI. Neurites of primary rat cerebral cortical neurons with depleted RPTPσ exhibited a significant enhancement in elongation and crossing ability when they encountered CSPGs in vitro. A contusion model of spinal cord injury in Wistar rats (the New York University (NYU) impactor) was used for in vivo experiments. Local injection of lentivirus encoding RPTPσ shRNA at the lesion site promoted axon regeneration and synapse formation, but did not affect the scar formation. Meanwhile, in vivo functional recovery (motor and sensory) was also enhanced after RPTPσ depletion. Therefore, strategies directed at silencing RPTPσ by RNAi may prove to be a beneficial, efficient and valuable approach for the treatment of SCI.

Keywords: Axon regeneration; Functional recovery; RNA interference; RPTPσ; Spinal cord injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Cerebral Cortex / cytology
  • Cerebral Cortex / pathology*
  • Disease Models, Animal
  • Female
  • Gene Expression Regulation / physiology
  • Glial Fibrillary Acidic Protein / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Nerve Regeneration / physiology
  • Neurites / physiology*
  • Neurons / pathology*
  • RNA, Small Interfering / physiology*
  • Rats
  • Rats, Wistar
  • Receptor-Like Protein Tyrosine Phosphatases, Class 2 / metabolism*
  • Recovery of Function / physiology*
  • Spinal Cord Injuries* / pathology
  • Spinal Cord Injuries* / physiopathology
  • Spinal Cord Injuries* / therapy
  • Time Factors
  • Transfection
  • Tubulin / genetics
  • Tubulin / metabolism

Substances

  • Glial Fibrillary Acidic Protein
  • RNA, Small Interfering
  • Tubulin
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Receptor-Like Protein Tyrosine Phosphatases, Class 2