3D co-cultures of keratinocytes and melanocytes and cytoprotective effects on keratinocytes against reactive oxygen species by insect virus-derived protein microcrystals

Mater Sci Eng C Mater Biol Appl. 2014 Sep;42:64-9. doi: 10.1016/j.msec.2014.05.013. Epub 2014 May 15.


Stable protein microcrystals called polyhedra are produced by certain insect viruses. Cytokines, such as fibroblast growth factors (FGFs), can be immobilized within polyhedra. Here, we investigated three-dimensional (3D) co-cultures of keratinocytes and melanocytes on collagen gel containing FGF-2 and FGF-7 polyhedra. Melanocytes were observed to reside at the base of the 3D cell culture and melanin was also typically observed in the lower layer. The 3D cell culture model with FGF-2 and FGF-7 polyhedra was a useful in vitro model of the epidermis due to effective melanogenesis, proliferation and differentiation of keratinocytes. FGF-7 polyhedra showed a potent cytoprotective effect when keratinocytes were treated with menadione, which is a generator of reactive oxygen species. The cytoprotective effect was activated by the inositol triphosphate kinase-Akt pathway leading to upregulation of the antioxidant enzymes superoxide dismutase and peroxiredoxin 6.

Keywords: 3D cell culture; Cytoprotection; FGF; Keratinocytes; Melanocytes; Polyhedra.

MeSH terms

  • Coculture Techniques
  • Fibroblast Growth Factor 2 / chemistry
  • Fibroblast Growth Factor 2 / pharmacology*
  • Insect Viruses
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Melanocytes / cytology
  • Melanocytes / drug effects*
  • Protective Agents / pharmacology*
  • Reactive Oxygen Species / metabolism*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / pharmacology
  • Viral Proteins / chemistry
  • Viral Proteins / pharmacology


  • Protective Agents
  • Reactive Oxygen Species
  • Recombinant Proteins
  • Viral Proteins
  • Fibroblast Growth Factor 2