Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Oct 15:170:53-67.
doi: 10.1016/j.actbio.2023.08.045. Epub 2023 Aug 26.

Osteogenic effects of covalently tethered rhBMP-2 and rhBMP-9 in an MMP-sensitive PEG hydrogel nanocomposite

Affiliations

Osteogenic effects of covalently tethered rhBMP-2 and rhBMP-9 in an MMP-sensitive PEG hydrogel nanocomposite

Sarah A Schoonraad et al. Acta Biomater. .

Abstract

While bone morphogenic protein-2 (BMP-2) is one of the most widely studied BMPs in bone tissue engineering, BMP-9 has been purported to be a highly osteogenic BMP. This work investigates the individual osteogenic effects of recombinant human (rh) BMP-2 and rhBMP-9, when tethered into a hydrogel, on encapsulated human mesenchymal stem cells (MSCs). A matrix-metalloproteinase (MMP)-sensitive hydrogel nanocomposite, comprised of poly(ethylene glycol) crosslinked with MMP-sensitive peptides, tethered RGD, and entrapped hydroxyapatite nanoparticles was used. The rhBMPs were functionalized with free thiols and then covalently tethered into the hydrogel by a thiol-norbornene photoclick reaction. rhBMP-2 retained its full bioactivity post-thiolation, while the bioactivity of rhBMP-9 was partially reduced. Nonetheless, both rhBMPs were highly effective at enhancing osteogenesis over 12-weeks in a chemically-defined medium. Expression of ID1 and osterix, early markers of osteogenesis; collagen type I, a main component of the bone extracellular matrix (ECM); and osteopontin, bone sialoprotein II and dentin matrix protein I, mature osteoblast markers, increased with increasing concentrations of tethered rhBMP-2 or rhBMP-9. When comparing the two BMPs, rhBMP-9 led to more rapid collagen deposition and greater mineralization long-term. In summary, rhBMP-2 retained its bioactivity post-thiolation while rhBMP-9 is more susceptible to thiolation. Despite this shortcoming with rhBMP-9, both rhBMPs when tethered into this hydrogel, enhanced osteogenesis of MSCs, leading to a mature osteoblast phenotype surrounded by a mineralized ECM. STATEMENT OF SIGNIFICANCE: Osteoinductive hydrogels are a promising vehicle to deliver mesenchymal stem cells (MSCs) for bone regeneration. This study examines the in vitro osteoinductive capabilities when tethered bone morphogenic proteins (BMPs) are incorporated into a degradable biomimetic hydrogel with cell adhesive ligands, matrix metalloproteinase sensitive crosslinks for cell-mediated degradation, and hydroxyapatite nanoparticles. This study demonstrates that BMP-2 is readily thiolated and tethered without loss of bioactivity while bioactivity of BMP-9 is more susceptible to immobilization. Nonetheless, when either BMP2 or BMP9 are tethered into this hydrogel, osteogenesis of human MSCs is enhanced, bone extracellular matrix is deposited, and a mature osteoblast phenotype is achieved. This bone-biomimetic hydrogel is a promising design for stem cell-mediated bone regeneration.

Keywords: Bone morphogenetic protein 2; Bone morphogenetic protein 9; Hydrogel nanocomposite; Mesenchymal stem cell; Osteogenesis.

PubMed Disclaimer

Conflict of interest statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Similar articles

References

    1. Bose S, Sarkar N, Natural Medicinal Compounds in Bone Tissue Engineering, Trends in Biotechnology. 38 (2020) 404–417. 10.1016/j.tibtech.2019.11.005. - DOI - PMC - PubMed
    1. Porter JR, Ruckh TT, Popat KC, Bone tissue engineering: A review in bone biomimetics and drug delivery strategies, Biotechnol Progress. (2009) NA-NA. 10.1002/btpr.246. - DOI - PubMed
    1. Zhang Y, Li Z, Guan J, Mao Y, Zhou P, Hydrogel: A potential therapeutic material for bone tissue engineering, AIP Advances. 11 (2021) 010701. 10.1063/5.0035504. - DOI
    1. Park Jb, The use of hydrogels in bone-tissue engineering, Med Oral. (2011) e115–e118. 10.4317/medoral.16.e115. - DOI - PubMed
    1. Du C, Huang W, Progress and prospects of nanocomposite hydrogels in bone tissue engineering, Nanocomposites. 8 (2022) 102–124. 10.1080/20550324.2022.2076025. - DOI

Publication types

MeSH terms

LinkOut - more resources

-