BME PhD Proposal Seminar: James Brennan
Using Fibronectin Matrix Mimetics to Stimulate Three-Dimensional Cellular Self-Assembly
Supervised by Prof. Denise Hocking
Tissue engineering is a rapidly emerging field that focuses on the design of biological substitutes to repair or replace dysfunctional or damaged human tissue or organs. One of the greatest challenges facing tissue engineers is replicating the natural processes that lead to the formation of functional three-dimensional (3D) tissue. A current approach to mimicking the in vivo process of tissue formation takes advantage of the ability of cells to self-assemble into 3D structures in vitro. The field of biomimetics aims to design biomaterials that mimic the structural and signaling functions of the extracellular matrix (ECM) to guide tissue formation in vitro. Fibronectin (FN) is an ECM protein that is polymerized into a biologically active matrix, and FN matrix assembly is necessary for the self-assembly of 3D aggregates in vitro. The Hocking lab has developed a series of recombinant proteins that mimic the ECM form of FN, and preliminary data show that an ECM FN mimetic adhesive substrate stimulates FN-dependent 3D cellular self-assembly. The overall goal of this proposal is to determine how ECM FN mimetics stimulate 3D cellular self-assembly. Rho GTPases (Rho, Rac, Cdc42) are a family of intracellular signaling proteins that regulate FN matrix assembly via actin cytoskeleton-mediated cell contractility. We propose a research plan to test the hypothesis that the ECM FN mimetic GST/III-1HRGD stimulates Rac-mediated FN matrix assembly to support 3D self-assembly. In Aim 1, I will identify the sites in GST/III-1HRGD that stimulate 3D self-assembly. In Aim 2, I will determine how adhesion to GST/III-1HRGD affects Rac activation during 3D self-assembly. Understanding how ECM FN mimetics stimulate 3D cellular organization will improve our ability to design biomaterials that direct tissue formation for tissue engineering applications.