If a man is known by the company he keeps, the same may be said of the cells in the human body. With a tendency to respond to mechanical cues, cells attach themselves to their neighbors and their surrounding extracellular matrix (ECM) by contracting and pulling on each other. They can also generate forces to build new tissue. In the company of a stiff surface, a stem cell may become a bone cell; on a soft surface, it may become a brain cell.
“This cell evolution is based on no other changes other than the surrounding stiffness,” said Christopher Lemmon, Ph.D., who is studying the signaling process among cells in his lab at the Virginia Commonwealth University School of Engineering. His work may change the way diseases are treated and tissues are generated.
“Understanding the mechanical cues might lead to a new paradigm in treating disease by targeting the mechanical properties of the tissue around it,” Lemmon explains. “Cells are reacting to what’s surrounding them. They’re pulling on what’s around them and responding to what they’re feeling. It’s really a different way of looking at disease.”
The work of Lemmon’s Cell and Matrix Mechanics Lab at VCU has health implications in two main areas: tissue engineering and cancer research.
“If we can learn how cells are assembling new tissues, we can mimic those strategies in regenerative medicine,” he said. “And in cancer research, where we know tissue assembly is happening excessively in the tumor environment, we are trying to address other ways we can block or stop it from happening in the first place.”
Mechanical signals and ECM proteins work together to facilitate changes in cells from one type to another. Epithelial cells lining tissues and organs can change into mesenchymal cells, the cells that build tissue, under certain conditions. Lemmon and his students are investigating how changes in both mechanical signals and the type of ECM protein affect this process through microcontact printing where different ECM proteins are stamped to surfaces such that only two cells can interact with each other. This allows researchers to precisely control and study the relationship between the two cells and determine what signals drive this change from epithelial to mesenchymal cell type.
“We want to understand how cells interpret mechanical signals from their surroundings and use those signals to grow new tissues. We’re interested in this in situations where it should happen such as embryonic development and tissue engineering and regenerative medicine, and in situations where it shouldn’t happen as in tumor growth in cancer, fibrosis and scarring in wound healing, liver disease and kidney disease.”
The work is funded through VCU Massey Cancer Center in conjunction with the American Cancer Society and a VCU Presidential Research Incentive Program award.
“Understanding mechanical cues might lead to a new paradigm in treating disease by targeting the mechanical properties of the tissue around it.”
– Christopher Lemmon, Ph.D.