Dorsal root ganglion neurons regulate the transcriptional and translational programs of osteoblast differentiation in a microfluidic platform

Cell Death Dis. 2017 Dec 13;8(12):3209. doi: 10.1038/s41419-017-0034-3.

Abstract

Innervation by the sensory nervous system plays a key role in skeletal development and in orchestration of bone remodeling and regeneration. However, it is unclear how and in which bone cells can sensory nerves act to control these processes. Here, we show a microfluidic coculture system comprising dorsal root ganglion (DRG) neurons and mesenchymal stem cells (MSCs) that more faithfully represents the in vivo scenario of bone sensory innervation. We report that DRG neurons promote the osteogenic differentiation capacity of MSCs, by mediating the increase of alkaline phosphatase activity and the upregulation of osteoblast-specific genes. Furthermore, we show that DRG neurons have a positive impact on Cx43 levels in MSCs during osteoblastogenesis, especially at an early stage of this process. Conversely, we described a negative impact of DRG neurons on MSCs N-cadherin expression at a later stage. Finally, we demonstrate a cytoplasmic accumulation of β-catenin translocation into the nucleus, and subsequently Lymphoid Enhancer Binding Factor 1-responsive transcriptional activation of downstream genes in cocultured MSCs. Together, our study provides a robust body of evidence that the direct interaction of DRG neurons with MSCs in a bone-like microenvironment leads to an enhancement of osteoblast differentiation potential of MSCs. The osteogenic effect of DRG neurons on MSCs is mediated through the regulation of Cx43 and N-cadherin expression and activation of the canonical/β-catenin Wnt signaling pathway.

MeSH terms

  • Alkaline Phosphatase / genetics
  • Alkaline Phosphatase / metabolism
  • Animals
  • Bone and Bones / cytology
  • Bone and Bones / metabolism
  • Cadherins / genetics*
  • Cadherins / metabolism
  • Cell Differentiation
  • Cell Proliferation
  • Coculture Techniques
  • Connexin 43 / genetics*
  • Connexin 43 / metabolism
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / metabolism*
  • Gene Expression Regulation
  • Lab-On-A-Chip Devices
  • Lymphoid Enhancer-Binding Factor 1 / genetics
  • Lymphoid Enhancer-Binding Factor 1 / metabolism
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / metabolism*
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism
  • Osteoblasts / cytology
  • Osteoblasts / metabolism*
  • Protein Biosynthesis
  • Rats
  • Rats, Wistar
  • Sensory Receptor Cells / cytology
  • Sensory Receptor Cells / metabolism*
  • Tissue Engineering / methods
  • Transcription, Genetic
  • Wnt Signaling Pathway*
  • beta Catenin / genetics
  • beta Catenin / metabolism

Substances

  • Cadherins
  • Connexin 43
  • Ctnnb1 protein, rat
  • Gja1 protein, rat
  • Lef1 protein, rat
  • Lymphoid Enhancer-Binding Factor 1
  • N-cadherin, rat
  • Nerve Tissue Proteins
  • beta Catenin
  • Alkaline Phosphatase