Purdue University

Characterizing the Feedback Loop Between Cells and the Pericellular Region During Cell-material Interactions - Project Summary Interactions Between Human Mesenchymal Stem Cells (HMSCS) and Their Environment Are a Main Factor in the Function of These Cells. Although the Importance of Cell-material Interactions Is Well Established, It Has Been Dif- Cult to Characterize This Complex Interplay, Especially in Vivo. During in Vivo Experiments, a Stem Cell Treatment's Efcacy Can Be Assessed, But the Underlying Cellular Processes and Change in the Surrounding Microenvironment That Leads to These Outcomes Remain a Black Box. Positive Outcomes May Result From These Experiments Even If There Is Loss of Function or Integrity in the Tissue Due to Failed Cell-material Interactions, Making Aspects of the Stem Cell Treatment Ineffective and Potentially Unnecessary. Since Real-time Measurement of These Interactions Has Not Been Realized in Vivo, in Vitro Models Provide an Alternative Approach to Measuring Cell-material Inter- Actions in Both 2D and 3D Culture. the Use of Scaffolds to Mimic Aspects of Native Tissue Provide Controlled Environments Where Cell-material Interactions Can Be Quantitatively Characterized. These Scaffolds Are Used for 3D Cell Encapsulation and Are Designed to Be Remodeled by Cells. This Creates a Feedback Loop Where the Cell Remodels the Pericellular Region and Responds to the Dynamically Changing Cues in the Environment. Real-time Characterization of These Dynamic Cell-material Interactions Continues to Be a Challenge. We Propose to Char- Acterize Dynamic Cell-material Interactions by Measuring Real-time Hmsc-mediated Scaffold Remodeling Using Microrheological Characterization and the Resulting Cellular Processes Using Cell Staining and Inhibition. We Will Use an Hmsc-laden Synthetic Hydrogel Scaffold That Mimics Aspects of Native Microenvironments to Present Cues to Cells. to Characterize HMSC Function, We Will Use Techniques Including Cell Staining and Pharmacological Inhibi- Tion of Molecules for Cellular Contractility and Matrix Adhesion. Our Unique Approach Will Characterize the Scaffold Microenvironment in Real-time During Cell-material Interactions. We Will Use Multiple Particle Tracking Microrhe- Ology (MPT) to Measure Hmsc-mediated Scaffold Remodeling and Degradation. This Technique Quanties the Spatio-temporal Evolution of the Rheology in the Pericellular Region, Which Is Part of the Feedback Loop That Denes Cell-material Interactions. Together, These Measurements Will Provide a Relationship Between Cellular Function and Cell-engineered Pericellular Rheology as the Complexity of the Scaffold Microenvironment Is Increased. the Pro- Posed Research Program Will Focus on Characterizing Cell-material Interactions During Specic Critical Processes That Are Not Fully Understood. the Processes We Will Study Are (1) Cellular Adhesion, (2) HMSC Motility in Re- Sponse to Scaffold Viscoelasticity and (3) Hmsc-material Interactions When Signaling Molecules Are Presented in the Environment. the Proposed Work Will Support the Overarching Goal of Understanding the Fundamentals of Cell-material Interactions and the Inuence on Basic Cellular Processes.