1.Thermodynamic studies on the adsorption of fibronectin adhesion-promoting peptide on nanothin films of poly(2-vinylpyridine) by SPR.
Li X1, Wei X, Husson SM. Biomacromolecules. 2004 May-Jun;5(3):869-76.
This paper describes a methodology for preparing uniform, nanothin polymer films for the study of biomolecule adsorption by surface plasmon resonance spectroscopy (SPR). The methodology combines molecular self-assembly of alkanethiols on gold with surface-confined atom transfer radical polymerization (ATRP). Poly(2-vinylpyridine) was chosen to demonstrate the methodology, and growth kinetics were studied by ex situ ellipsometry. Atomic force microscopy (AFM) indicated that the polymer films were uniform with RMS roughness of approximately 0.5 nm. Subsequent SPR measurements were done to determine thermodynamic adsorption properties (deltaG, deltaH, and deltaS) between fibronectin adhesion-promoting peptide and the surface-confined poly(2-vinylpyridine) at 15, 20, and 25 degrees C. The flexibility in synthesis conditions and the opportunities for manipulating film thicknesses and graft densities that ATRP provides to grow polymer films from gold surfaces holds advantages over conventional spin-coating and grafting to approaches in the design of model polymer films for biomolecule adsorption studies.
2.Corneal epithelial cell growth over tethered-protein/peptide surface-modified hydrogels.
Jacob JT1, Rochefort JR, Bi J, Gebhardt BM. J Biomed Mater Res B Appl Biomater. 2005 Jan 15;72(1):198-205.
In this study, we investigated the corneal epithelial cell growth rate and adhesion to novel hydrogels with (1) extracellular matrix proteins [fibronectin, laminin, substance P, and insulin-like growth factor-1 (IGF-1)] and (2) peptide sequences [RGD and fibronectin adhesion-promoting peptide (FAP)] tethered to their surface on poly(ethylene glycol) (PEG) chains. The growth rate to confluence of primary rabbit cornea epithelial cells was compared for plain polymethacrylic acid-co-hydroxyethyl methacrylate (PHEMA/MAA) hydrogels, PHEMA/MAA hydrogels coated with extracellular matrix proteins or peptides, and PHEMA/MAA hydrogels with tethered extracellular matrix proteins or peptides on the surface. The development of focal adhesions by the epithelial cells grown on the surfaces was determined by F-actin staining. Little to no epithelial cell growth occurred on the plain hydrogel surfaces throughout the 15-day culture period. Of the coated hydrogels, only the fibronectin-coated surfaces showed a significant increase in cell growth compared to plain hydrogels (p < 0.
3.Fibronectin stimulates the osteogenic differentiation of murine embryonic stem cells.
Kang Y1, Georgiou AI1, MacFarlane RJ1, Klontzas ME1, Heliotis M2, Tsiridis E3, Mantalaris A1. J Tissue Eng Regen Med. 2015 Oct 9. doi: 10.1002/term.2090. [Epub ahead of print]
Conditioned medium from human hepatocarcinoma cells (HepG2-CM) has been shown to stimulate the osteogenic/chondrogenic differentiation of murine embryonic stem cells (mESCs). HepG2-CM is considered to contain visceral endoderm (VE)-like signals and attempts have recently been made to characterize it, using proteomic profiling, with fibronectin being identified as one promising candidate. Herein, we investigated whether fibronectin is able to mimic the activities of HepG2-CM during the osteogenic differentiation of mESCs. Specifically, the addition of RGD peptides and heparin in HepG2-CM significantly reduced the growth- and adhesion-promoting effects of HepG2-CM, in addition to suppressing its osteogenic-inductive activity. Furthermore, direct addition of fibronectin to basal medium was able to reproduce, at least partially, the function of HepG2-CM. In particular, fibronectin induced the early onset of osteogenic differentiation in mESCs, as confirmed by gene expression of osteogenic markers, and resulted in the three-fold higher calcium deposition at day 11 of osteogenic culture compared to the control group.
4.A synthetic peptide from the heparin-binding domain III (repeats III4-5) of fibronectin promotes stress-fibre and focal-adhesion formation in melanoma cells.
Moyano JV1, Maqueda A, Albar JP, Garcia-Pardo A. Biochem J. 2003 Apr 15;371(Pt 2):565-71.
Cell adhesion to fibronectin results in formation of actin stress fibres and focal adhesions. In fibroblasts, this response requires two co-operative signals provided by interactions of the RGD sequence with alpha5beta1 integrin and the heparin-binding domain II (Hep II) domain with syndecan-4. Within Hep II, this activity was mapped to repeat III13 and to the peptide FN-C/H-V(WQPPRARITGY, repeat III14). We previously described that the synthetic heparin-binding peptide/III5 (HBP/III5) (WTPPRAQITGYRLTVGLTRR, repeat III5) binds heparin and mediates cell adhesion via chondroitin sulphate proteoglycans. We have now studied whether HBP/III5 co-operates with alpha5beta1 and drives a full cytoskeletal response in melanoma cells. SKMEL-178 cells attached and spread on the RGD-containing FNIII7-FNIII10 (FNIII7-10) fragment, but did not form stress fibres or focal adhesions. Co-immobilization of HBP/III5 with FNIII7-10 or adding soluble HBP/III5 to cells prespread on FNIII7-10, effectively induced these structures.
