Inhibition of Cx43 mediates protective effects on hypoxic/reoxygenated human neuroblastoma cells

J Cell Mol Med. 2017 Oct;21(10):2563-2572. doi: 10.1111/jcmm.13177. Epub 2017 May 9.


Olfactory ensheathing cells (OECs), a special population of glial cells, are able to synthesise several trophic factors exerting a neuroprotective action and promoting growth and functional recovery in both in vitro and in vivo models. In the present work, we investigated the neuroprotective effects of OEC-conditioned medium (OEC-CM) on two different human neuron-like cell lines, SH-SY5Y and SK-N-SH (neuroblastoma cell lines), under normoxic and hypoxic conditions. In addition, we also focused our attention on the role of connexins (Cxs) in the neuroprotective processes. Our results confirmed OEC-CM mediated neuroprotection as shown by cell adherence, proliferation and cellular viability analyses. Reduced connexin 43 (Cx43) levels in OEC-CM compared to unconditioned cells in hypoxic conditions prompted us to investigate the role of Cx43-Gap junctions (GJs) and Cx43-hemichannels (HCs) in hypoxic/reoxygenation injury using carbenoxolone (non-selective GJ inhibitor), ioxynil octanoato (selective Cx43-GJ inhibitor) and Gap19 (selective Cx43-HC inhibitor). We found that Cx43-GJ and Cx43-HC inhibitors are able to protect SH-SY5Y and allow to these cultures to overcome the injury. Our findings support the hypothesis that both OEC-CM and the inhibition of Cx43-GJs and Cx43-HCs offer a neuroprotective effect by reducing Cx43-mediated cell-to-cell and cell-to-extracellular environment communications.

Keywords: connexin 43; gap junctions; growth factors; neuroprotection; olfactory glia.

MeSH terms

  • Animals
  • Animals, Newborn
  • Cell Adhesion / drug effects
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Cell Survival / drug effects
  • Cells, Cultured
  • Connexin 43 / antagonists & inhibitors*
  • Connexin 43 / chemistry
  • Connexin 43 / metabolism
  • Culture Media, Conditioned / pharmacology*
  • Gap Junctions / drug effects
  • Gap Junctions / metabolism
  • Humans
  • Mice
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology
  • Neuroprotective Agents / pharmacology
  • Olfactory Bulb / cytology
  • Olfactory Bulb / metabolism
  • Oxygen / metabolism*
  • Peptide Fragments / pharmacology*


  • Connexin 43
  • Culture Media, Conditioned
  • Neuroprotective Agents
  • Peptide Fragments
  • Oxygen