New Method of Cell Movement in 3D Matrix Discovered

Scientists have taken a closer look at how cells move by examining a three-dimensional matrix. Now, they've announced that they've discovered an entirely new type of cell movement that involves the nucleus propelling cells through the matrix like a piston in an engine.

"Our work elucidated a highly intriguing question: how cells move when they are in the complex and physiologically relevant environment of a 3D extracellular matrix," said Hyun (Michel) Koo, one of the researchers, in a news release. "We discovered that the nucleus can act as a piston that physically compartmentalizes the cell cytoplasm and increases the hydrostatic pressure driving the cell motility within a 3D matrix."

More specifically, the scientists studied fibroblasts, which are the most common type of cell found in connective tissue. Fibroblasts actually produce proteins, including collagen and fibronectin, that connect in a complex matrix that is found in tissues in the body. The most common type of movement for fibroblasts on 2D surfaces involved protrusions, called lamellipodia, which push the cell membrane forward.

In this case, the researchers used a fibroblast-created matrix to test how cells migrate through a 3D structure. They then used microelectrodes to measure the hydrostatic pressure of the fluid inside the cell. They found that the pressure was significantly higher in cells moving in a 3D extracellular matrix. Then, the scientists measured the pressure from in front of and behind the nucleus to see how the pressure was distributed. In the end, they found a new type of cell movement.

"When a cell is in the matrix, the nucleus tends to be at the back of the cell, and the cell body is very tubular in shape," said Ryan Petrie, one of the researchers. "I t really looks like a piston. The pressure itself is what pushes the plasma membrane."

The findings are published in the journal Science.