Sensing of micropillars by osteoblasts involves complex intracellular signaling

J Mater Sci Mater Med. 2017 Sep 27;28(11):171. doi: 10.1007/s10856-017-5982-8.

Abstract

Topographical material surface features are sensed by cells and provoke a large range of cellular responses. We recognized earlier, that at micropillar topographies in the range of 5 µm, the osteoblasts attempt to phagocytize the pillars resulted in increased energy requirements and reduced osteoblast marker expression, e.g., collagen type I and osteocalcin. However, the precise cellular signaling transducing the topographic information into the cell and evoking phagocytic processes remained unknown. Here, we could show that the RhoA/ROCK signaling is involved in the transduction of the topography-mediated cellular reactions. After inhibition of ROCK-2 with Y27632 for 24 h, no caveolae-mediated micropillar assembly of the cell membrane domain component caveolin-1 (Cav-1) was found. ROCK inhibition was also able to attenuate the pillar-induced decrease in β-actin. Interestingly, phosphatidylinositol 3-kinase (PI3K) inhibition with LY294002 for 24 h did not influence the Cav-1 clustering on micropillars. Our results illustrate the importance of the integrin down-stream signaling of RhoA/ROCK in the recognition of and adaption to surface microtopographies by osteoblasts and extend our understanding about the complex mechanism of action inside the cells.

MeSH terms

  • Cell Adhesion / physiology
  • Cell Communication / physiology*
  • Cells, Cultured
  • Humans
  • Mechanotransduction, Cellular / physiology*
  • Nanostructures / chemistry*
  • Osteoblasts / cytology
  • Osteoblasts / metabolism
  • Osteoblasts / physiology*
  • Signal Transduction / physiology
  • Surface Properties
  • Tissue Scaffolds / chemistry*
  • rho-Associated Kinases / metabolism
  • rho-Associated Kinases / physiology
  • rhoA GTP-Binding Protein / metabolism
  • rhoA GTP-Binding Protein / physiology

Substances

  • rho-Associated Kinases
  • rhoA GTP-Binding Protein