The Effects of Stably Tethered BMP-2 on MC3T3-E1 Preosteoblasts Encapsulated in a PEG Hydrogel

Biomacromolecules. 2021 Mar 8;22(3):1065-1079. doi: 10.1021/acs.biomac.0c01085. Epub 2021 Feb 8.

Abstract

Bone morphogenetic protein-2 (BMP-2) is a clinically used osteoinductive growth factor. With a short half-life and side effects, alternative delivery approaches are needed. This work examines thiolation of BMP-2 for chemical attachment to a poly(ethylene glycol) hydrogel using thiol-norbornene click chemistry. BMP-2 retained bioactivity post-thiolation and was successfully tethered into the hydrogel. To assess tethered BMP-2 on osteogenesis, MC3T3-E1 preosteoblasts were encapsulated in matrix metalloproteinase (MMP)-sensitive hydrogels containing RGD and either no BMP-2, soluble BMP-2 (5 nM), or tethered BMP-2 (40-200 nM) and cultured in a chemically defined medium containing dexamethasone for 7 days. The hydrogel culture supported MC3T3-E1 osteogenesis regardless of BMP-2 presentation, but tethered BMP-2 augmented the osteogenic response, leading to significant increases in osteomarkers, Bglap and Ibsp. The ratio, Ibsp-to-Dmp1, highlighted differences in the extent of differentiation, revealing that without BMP-2, MC3T3-E1 cells showed a higher expression of Dmp1 (low ratio), but an equivalent expression with tethered BMP-2 and more abundant bone sialoprotein. In addition, this work identified that dexamethasone contributed to Ibsp expression but not Bglap or Dmp1 and confirmed that tethered BMP-2 induced the BMP canonical signaling pathway. This work presents an effective method for the modification and incorporation of BMP-2 into hydrogels to enhance osteogenesis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Biocompatible Materials*
  • Bone Morphogenetic Protein 2*
  • Cell Differentiation
  • Hydrogels
  • Osteogenesis

Substances

  • Biocompatible Materials
  • Bone Morphogenetic Protein 2
  • Hydrogels