Collaborative Research: Effects of Three-Dimensional Tissue Structure and Mechanics on Cellular Behavior

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Cells in living organisms reside in a meshwork of protein fibers and other molecules, termed the extracellular matrix, which provides both structural support and chemical inputs that are critical to the functioning of the cells. The structural properties of the extracellular matrix are largely determined by how these protein fibers are aligned and organized, and changes in these structures and are associated with the progression of many human diseases, but in ways that in many cases are still not well understood. This award supports fundamental research that will provide needed insights into how the organization and resulting mechanical properties of the extracellular matrix influence and control both the normal and pathological behavior of cells. A novel cell culture system results leads cells to build a protein matrix that has controlled shape and orientation of the protein meshwork. The meshwork can be stretched and deformed using another novel tool and the response of the cells to deformation of the oriented matrix is measured. This research is relevant to ongoing efforts to develop methods to speed wound healing, and to engineer artificial tissues to repair damaged organs, and so the results from this work will have broad impact and provide critical resources to the biomedical community. This collaborative research program involves techniques and insights drawn from several fields, including bioengineering, physics, microfabrication, and cell biology, and provides interdisciplinary training needed to prepare the next generation of scientists and engineers. The adhesion of cells to the extracellular matrix plays a major role in many critical cellular functions important to embryonic development, adult tissue homeostasis, and disease pathogenesis, including cell survival, migration, proliferation, and differentiation. Yet, there have been few systems that allow control and therefore study the specific effects of fibrillar extracellular matrix architecture on cell function. This project use engineered microtissues to address the key hypothesis that alterations in the alignment of matrix, contractile activity of resident cells, geometry of boundary constraints, and external mechanical forces are highly coupled in a mechanotransduction machinery that will drive changes in cellular phenotype. These studies will determine how these factors regulate the transition of fibroblasts to an activated, fibrotic phenotype that is critical in wound healing as well as chronic fibrosis and scarring, but will apply more broadly to many cell types that response to mechanoadhesive cues.