Single or Mixed Tethered Peptides To Promote hMSC Differentiation toward Osteoblastic Lineage

Abstract

The commitment and differentiation of human mesenchymal stem cells (hMSCs) are guided by bioactive molecules within the extracellular matrix. Among the various approaches to design biomaterials, the functionalization of biomaterial surfaces with peptides from the sequence of proteins from the extracellular matrix is quite common. The purpose of this functionalization is to recruit hMSCs and promote their differentiation into the appropriate lineage. The aim of this work was to investigate the influence of RGD and FHRRIKA peptides and peptide sequences taken from bone morphogenic protein (BMP-2) and histone H4 (osteogenic growth peptide; OGP) either tethered alone or as a mixture on the surface of a model material and to also examine the level of hMSC osteogenic commitment without using a differentiation medium. Grafting of the different peptides was assessed by X-ray photoelectron spectroscopy (XPS), while their surface density was quantified by fluorescence microscopy, and their surface properties were assessed by atomic force microscopy (AFM) and contact angle (CA). The osteogenic commitment of hMSCs cultured on the different surfaces was characterized by immunohistochemistry using Runx-2 as an earlier osteogenic marker and OPN, a late osteogenic marker, and by RT-qPCR through the expression of ColI-a1, Runx-2, and ALP. Biological results show that the osteogenic commitment of the hMSCs was increased on surfaces tethered with a mixture of peptides. Results indicate that tethered peptides in the range of pmol mm −2 were indeed effective in inducing a cellular response after 2 weeks of cell culture without using an osteogenic media. These findings contribute to the research efforts to design biomimetic materials able to induce a response in human stem cells through tethered bioactive molecules for bone tissue engineering.

Evaluating Poly(Acrylamide‐co‐Acrylic Acid) Hydrogels Stress Relaxation to Direct the Osteogenic Differentiation of Mesenchymal Stem Cells

“…As polyacrylamide‐based materials do not support cell adhesion, [ 29,30 ] these hydrogels have been functionalized with a mimetic peptide of the bone morphogenetic protein‐2 (BMP‐2), which corresponds to residues 73–92 of BMP‐2 and has been shown to induce hMSCs osteoblast differentiation when grafted onto different materials (glass, polyethylene terephthalate, poly(acrylamide‐ co ‐acrylic acid) hydrogel). [ 69–73 ] Hydrogels functionalization has been assessed by using fluorescently labeled BMP‐2 peptide and by following previously described protocols. [ 69,71–73 ] It has been found that the fluorescence intensity on the surface of the two hydrogels with low and high relaxation is similar (data not shown), indicating that the peptide density lies within the same range between the two hydrogels.…”

“…[ 69–73 ] Hydrogels functionalization has been assessed by using fluorescently labeled BMP‐2 peptide and by following previously described protocols. [ 69,71–73 ] It has been found that the fluorescence intensity on the surface of the two hydrogels with low and high relaxation is similar (data not shown), indicating that the peptide density lies within the same range between the two hydrogels.…”

Mesenchymal Stem Cell Differentiation Driven by Osteoinductive Bioactive Nanoscale Topographies

“…Most studies take advantage of only the sequence responsible for the osteogenic activity of this molecule to functionalize biomaterials for bone tissue engineering applications [19,32,33]. The combination of a peptide promoting cell adhesion with one promoting cell differentiation for the co-functionalization of a biomaterial has been reported to further enhance differentiation when compared with the grafting of only one peptide sequence, such as a BMP-2 mimetic peptide [34][35][36][37][38]. Several studies can be found reporting also synergistic effects of combining nanotopographies with chemical cues on osteogenic differentiation of hMSCs or osteoblast progenitors [39][40][41].…”

Controlled co‐immobilization of biomolecules on quinone‐bearing plasma polymer films for multifunctional biomaterial surfaces

“…This latter approach is based on the immobilization of a cocktail of biomolecules, thus implicitly complexifying the issue related to biomolecule immobilization. [8] Various routes are already reported for the multifunctionalization of surfaces, namely (a) the successive immersion, generally in overestimated durations, of a single surface in different biomolecule-containing solutions [9] ; (b) the single immersion of a surface in a solution containing a mixture of biomolecules [10] ; and (c) the immobilization of synthetic and multifunctional biomolecules, also known as fusion proteins. [11] More importantly, most biomaterial surfaces lack chemical reactive sites, thus limiting their potential for biomolecule covalent modifications toward the development of functional coatings.…”

“…Various routes are already reported for the multifunctionalization of surfaces, namely (a) the successive immersion, generally in overestimated durations, of a single surface in different biomolecule‐containing solutions [ 9 ] ; (b) the single immersion of a surface in a solution containing a mixture of biomolecules [ 10 ] ; and (c) the immobilization of synthetic and multifunctional biomolecules, also known as fusion proteins. [ 11 ]…”