Enzymatic Crosslinking and Degradation of Gelatin as a Switch for Bone Morphogenetic protein-2 Activity

Tissue Eng Part A. 2011 Dec;17(23-24):2955-64. doi: 10.1089/ten.tea.2011.0290. Epub 2011 Sep 1.

Abstract

Current therapies for tissue regeneration rely on the presence or direct delivery of growth factors to sites of repair. Bone morphogenetic protein-2 (BMP-2), combined with a carrier (usually collagen), is clinically proven to induce new bone formation during spinal fusion and nonunion repair. However, due to BMP-2's short half-life and its diffusive properties, orders of magnitude above physiological levels are required to ensure effectiveness. In addition, a high dose of this multifunctional growth factor is known to induce adverse effects in patients. To circumvent these challenges, we proposed and tested a new approach for BMP-2 delivery, by controlling BMP activity via carrier binding and localized proteolysis. BMP-2 was covalently bound to gelatin through site-specific enzymatic crosslinking using a microbial transglutaminase. Binding of BMP-2 to gelatin can completely switch off BMP-2 activity, as evidenced by loss of its transdifferentiating ability toward C2C12 promyoblasts. When gelatin sequestered BMP-2 is incubated with either microbial collagenase or tissue-derived matrix metalloproteinases, BMP-2 activity is fully restored. The activity of released BMP-2 correlates with the protease activity in a dose- and time-dependent manner. This observation suggests a novel way of delivering BMP-2 and controlling its activity. This improved delivery method, which relies on a physiological feedback, should enhance the known potential of this and other growth factors for tissue repair and regeneration.

MeSH terms

  • Animals
  • Bone Morphogenetic Protein 2 / metabolism*
  • Bone and Bones / pathology
  • Cell Line
  • Choristoma / pathology
  • Collagenases / metabolism
  • Cross-Linking Reagents / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Enzymes / metabolism*
  • Gelatin / metabolism*
  • Matrix Metalloproteinases / metabolism
  • Mice
  • Models, Biological
  • Osteogenesis
  • Proteolysis*
  • Rats
  • Streptomyces / enzymology
  • Time Factors
  • Transglutaminases / metabolism

Substances

  • Bone Morphogenetic Protein 2
  • Cross-Linking Reagents
  • Enzymes
  • Gelatin
  • Transglutaminases
  • Collagenases
  • Matrix Metalloproteinases