Surface-Directed Differentiation of Human Mesenchymal Stem Cells on Orthogonal Peptide Concentration Gradient Surfaces

University Of Akron, Akron OH

Investigators

Abstract

This award by the Biomaterials program in the Division of Materials Research to University of Akron is in support of research that seeks to quantify the concentration dependence and spatial nature of ligand-receptor interactions, which influence cell differentiation pathways in human mesenchymal stem cells. Future advances in regenerative medicine will require the use of more than one peptide or bioactive molecule to drive stem cells into well-defined specifically differentiated populations. While many investigations have focused on individual molecular interactions at discrete concentrations, a complete interactome of the concentration dependence of extra cellular matrix-derived, osteogenic growth peptide and short peptide fragments of bone morphogenic proteins singly and in combination has remained elusive. The gradient approach also affords a method to decouple local signaling that occurs due to cell-integrin interactions from soluble paracrine effects. When identified, this information will drive the design of higher-order bioactive and biomimetic materials for use in several applications where synthetic materials contact biological systems. The aims of the proposal outline an approach to fabricate and characterize both unidirectional and orthogonal peptide concentration (10-200 pm/cm2 for unidirectional and 10-100 pm/cm2 for orthogonal) gradients. Using a multidimensional characterization approach with surface spectroscopy, immunohistochemistry, automated fluorescence microscopy and real-time polymerase chain reaction, the project will capture the concentration thresholds and synergistic signaling events that influence cell proliferation, lineage commitment and population heterogeneities. The multidisciplinary research ecosystem will offer training opportunities to researchers at all levels (high school, undergraduate, graduate and postdoctoral) at the cutting edge of materials chemistry, chemical biology and regenerative medicine. In partnership with a local high school, real world research activities will be incorporated into age-appropriate modules into upper level biology courses and will be used to teach fundamental concepts and relationships between both physics and chemistry. One of the major remaining barriers to advancing regenerative medicine into mainstream applications is the issue of reliable, safe cell sources. In the near term, stem cells for surgical implantation must come from the person needing the replacement part (autologous sourcing). This limitation will require a pre-surgical isolation of stem cells followed by an expansion protocol ex vivo (outside the body) to generate enough stem cells for the scaffold seeding. The existing synthetic materials are insufficient for these protocols. This proposal outlines an approach to identify the optimal combinations and concentrations of small biomimetic peptides to yield large quantities of well-defined stem cell populations. The autologous approach is free of most safety and ethical concerns that have been raised by various populations. If successful, the identified concentrations will have far reaching impact on our understanding of how individual and combinations of peptides influence cell differentiation and furthermore improve the quantity and quality of well-defined stem cell populations available for research and clinical investigations. The multidisciplinary research environment offers opportunities for training at all levels (high school, undergraduate, graduate and postdoctoral). The project involves training students, undergraduate, and high school students from a local school. The age appropriate educational modules will be designed to teach fundamental principles to high school biology courses at various levels using advanced research topics. It is critical to encourage students at this age to understand the importance of engineering principles and how they relate to advancing human health. This project is expected to support the nation's efforts to increase the numbers and diversity of the engineering student pipeline that require one to reach down and providing unique research opportunities to underrepresented/minority students populations which encourage the pursuit of science and engineering careers.