Collagen-mimetic hydrogels promote human endothelial cell adhesion, migration and phenotypic maturation

Abstract

This work evaluates the response of human aortic endothelial cells (HAECs) to thromboresistant collagen-mimetic hydrogel coatings toward improving the biocompatibility of existing “off-the-shelf” small-caliber vascular grafts. Specifically, bioactive hydrogels – previously shown to support α1/α2 integrin-mediated cell adhesion but to resist platelet activation – were fabricated by combining poly(ethylene glycol) (PEG) with a 120 kDa, triple-helical collagen-mimetic protein(Scl2-2) containing the GFPGER adhesion sequence. Analysis of HAECs seeded onto the resulting PEG-Scl2-2 hydrogels demonstrated that HAEC adhesion increased with increasing Scl2-2 concentration, while HAEC migration rate decreased over this same concentration range. In addition, evaluation of HAEC phenotype at confluence indicated significant differences in the gene expression of NOS3, thrombomodulin, and E-selectin on the PEG-Scl2-2 hydrogels relative to PEG-collagen controls. At the protein level, however, only NOS3 was significantly different between the PEG-Scl2-2 and PEG-collagen surfaces. Furthermore, PECAM-1 and VE-cadherin expression on PEG-Scl2-2 hydrogels versus PEG-collagen controls could not be distinguished at either the gene or protein level. Cumulatively, these data indicate the PEG-Scl2-2 hydrogels warrant further investigation as “off-the-shelf” graft coatings. In future studies, the Scl2-2 protein can potentially be modified to include additional extracellular matrix or cytokine binding sites to further improve endothelial cell responses.

Bioconjugation of a Collagen-Mimicking Peptide Onto Poly(vinyl alcohol) Encourages Endothelialization While Minimizing Thrombosis

“…The EC attachment attained is likely through the α1β1 and α2β1 integrins, which are well known to interact with GFPGER (Seo et al, 2010). This cell attachment is in agreement with the work of several groups, including ours (Chaouat et al, 2008;Munoz-Pinto et al, 2015;Anderson et al, 2019). GFPGER has been shown to support cell attachment and spreading on several surfaces, including a collagen-mimetic protein with GFPGER incorporated, Scl2 GFPGER , coated onto tissue culture plastic (Seo et al, 2010) and a Scl2 GFPGER incorporated PEG hydrogel (Cereceres et al, 2015).…”

“…Both of these sequences specifically recognize α1β1 and α2β1 integrins, which are known to bind ECs and both bind and upregulate platelet activation. The incorporation of GFPGER into materials has been shown to promote cell growth and, while in solution, the GFPGER sequence bound platelets but did not cause activation of the platelets (Munoz-Pinto et al, 2015). The effect on platelet attachment and aggregation due to a covalently linked GFPGER surface is unknown.…”

A Review of Integrin-Mediated Endothelial Cell Phenotype in the Design of Cardiovascular Devices

“…85,168 Studies have also been performed on collagen mimics such as these peptide sequences that have more tailored integrin interactions. 49,112,139 These typically require coating studies or chemical crosslinking into another network, as they do not form networks on their own. 107 Collagen coat studies have demonstrated a difference in not only cell behaviors such as migration and proliferation as compared to TCPS but also differences in hemostatic regulation.…”

“…107 Collagen coat studies have demonstrated a difference in not only cell behaviors such as migration and proliferation as compared to TCPS but also differences in hemostatic regulation. 53,96,112,165 For example, endothelial cells cultured on collagen-coated ePTFE demonstrated lower levels of PGI 2 and tPA as compared to endothelial cells on an un-coated ePTFE control. 100 This would indicated a less thromboresistant phenotype, but this study did not analyze the production of complementary pro-thrombotic factors in the endothelial cells cultured on these substrates.…”

Customizable biomaterials as tools for advanced anti-angiogenic drug discovery

“…In one study, human aortic endothelial cells (HAECs) were cultured in the presence of either full-length Collagen or a Collagen-mimicking peptide SCL2–2 presented on PEG hydrogels. SCL2–2 is a Collagen mimicking protein presenting mainly Gly-Phe-Pro-Gly-Glu-Arg (GFPGER) as the integrin-binding domain [90]. HAECs adhered to full-length collagen had greater levels of NOS3 protein expression, greater gene expression levels of NOS3, Thrombomodulin and Selectin-E, and proliferation when compared to HAECs adhered to SCL2–2.…”