Copresentation of BMP-6 and RGD Ligands Enhances Cell Adhesion and BMP-Mediated Signaling

Abstract

We report on the covalent immobilization of bone morphogenetic protein 6 (BMP-6) and its co-presentation with integrin ligands on a nanopatterned platform to study cell adhesion and signaling responses which regulate the transdifferentiation of myoblasts into osteogenic cells. To immobilize BMP-6, the heterobifunctional linker MU-NHS is coupled to amine residues of the growth factor; this prevents its internalization while ensuring that its biological activity is maintained. Additionally, to allow cells to adhere to such platform and study signaling events arising from the contact to the surface, we used click-chemistry to immobilize cyclic-RGD carrying an azido group reacting with PEG-alkyne spacers via copper-catalyzed 1,3-dipolar cycloaddition. We show that the copresentation of BMP-6 and RGD favors focal adhesion formation and promotes Smad 1/5/8 phosphorylation. When presented in low amounts, BMP-6 added to culture media of cells adhering to the RGD ligands is less effective than BMP-6 immobilized on the surfaces in inducing Smad complex activation and in inhibiting myotube formation. Our results suggest that a local control of ligand density and cell signaling is crucial for modulating cell response.

An Engineered Biomimetic Peptide Regulates Cell Behavior by Synergistic Integrin and Growth Factor Signaling

“…This is in agreement with other studies that propose as well that the proximity of GF and integrins favors cell adhesion. [ 15,22,26 ] Moreover, cell adhesion on the samples functionalized with the RGD‐DWIVA peptide was effectively inhibited when C2C12 cells were preincubated with the potent integrin antagonist Cilengitide, [ 49 ] showing the synergistic enhancement in cell adhesion is specifically mediated by integrin binding to the surface.…”

“…[ 20,22,24,25 ] Recently, a specificity in integrin crosstalk with bound BMP‐2 has been shown by using surface nanopatterning of single BMPs homodimers copresented with integrin ligands. [ 26,27 ] While this approach shows that the nanoscale control over BMP‐2 distribution and the proximity of the GF with integrin binding sites favors cell adhesion and BMP‐mediated signaling, it is not possible with such system to control the stoichiometry of receptor binding sites, because the integrin ligands are sparsely distributed on the surface.…”

BMP‐6 Loaded Polyelectrolyte Complex Nanoparticles Inducing Osteogenic Differentiation and Apoptosis of Malignant Plasma Cells for Local Treatment of Multiple Myeloma

“…[ 10 ] Other nano‐based strategies investigating the biological activity of immobilized BMP‐6 in concentrations down to 1 ng show enhanced duration of signaling and activity compared to soluble BMPs, making this an interesting approach for BSM. [ 27 ]…”

“…Aspirates were subjected to density centrifugation followed by CD138‐purification using an AutoMACS Pro (Miltenyi, Bergisch Gladbach, Germany) as previously published. [ 9–33 ] For the experiments, negative fractions of plasma cell purification still containing malignant plasma cells alongside the mononuclear compartment of the bone marrow were used as previously described. [ 9 ] Cells were cultured in RPMI‐1640 medium supplemented with 10% fetal calf serum (FCS) and 2 ng mL −1 IL‐6.…”

Cytokine Directed Chondroblast Trans-Differentiation: JAK Inhibition Facilitates Direct Reprogramming of Fibroblasts to Chondroblasts

“…Multiple studies demonstrated that it is possible to directly trans-differentiate one adult cell type to the other using small molecules. Other studies investigated the underlying mechanisms [12][13][14]. These experiments, however, demonstrated that changes could only take place within cells from the same germ layer.…”