Engineering Synthetic ECM Analogs Using Elastin Mimetic Peptides

Engineering Synthetic ECM Analogs Using Elastin Mimetic Peptides

Developing biomaterials which provide cellular cues for increased extra-cellular matrix (ECM) deposition has rendered much research interest in the past few years.  The ECM is comprised of several cell secreted proteins which provide cellular cues for migration, proliferation, and differentiation.  Furthermore, the ECM is responsible for creating a suitable microenvironment for cell sustainability within a tissue.  Current technology in biomaterial application limits the amount of ECM deposition resulting in decreased cell viability within the biomaterial.  Herein we engineered two different elastin mimetic peptides, EM-19 and EM-23, capable of inducing cells to produce a viable ECM once incorporated into a biomaterial.  Elastin is a major ECM protein commonly found in vascular tissue.  Although highly hydrophobic, elastin strongly interacts with cells using the hexapeptide sequence VGVAPG triggering cells to induce vascular ECM formation.  Our previous report suggests that the peptides EM-19, AAKAAKVGVAPGAAKAAKK, and EM-23, AAKAAKVGVAPGRGDSAAKAAKK, are capable of self-assembling within the deposited elastin matrix¹.  The presence of RGDS in EM-23 has also been shown to increase the ability of the peptide to self-integrate into the elastin matrix while inducing more elastin deposition¹.  In this report, we covalently integrated either peptide, 5 µmol/ml, into a 10 % w/v poly(ethylene) glycol diacrylate (PEGDA) hydrogel with smooth muscle cells (SMCs).  After 48 hours incubation, we evaluated elastin production using a Fastin assay (Fig 1).  Our data suggests that either peptide has the capability of serving as ECM templates once incorporated into the hydrogel.

Fig 1. Percent increase for elastin production in the presence of different elastin mimetic peptides within a 10 % w/v PEGDA hydrogel.  Scrambled versions, where VGVAPG was scrambled to VGVPAG, of EM-19 and EM-23 are denoted as EM-19S and EM-23S, respectively.  Significantly increased elastin production was observed on all peptides except for EM-19S in comparison to bare PEGDA; with EM-23 showing the highest ability to induce elastin production. * denotes p<0.05 from PEGDA with at least 6 samplings.

1. Patel, D., et.al., Self-Assembly of Elastin-Based Peptides into the ECM: the Importance of Integrins and the Elastin Binding Protein in Elastic Fiber Assembly. Biomacromolecules 2011 12: pg 432-440.