|Research from Sally Temple, a stem cell biologist at the New York Neural Stem Cell Institute, has shown that neural stem cells are typically found near blood vessels. The outer surface of blood vessels is composed of a specialized type of cell called endothelial cells. Thompson is looking at how an artifical niche composed of endothelial cells in different configurations impacts the neural stem cell growth and differentiation.
“If we can develop a reliable source of neural stem cells, we might some day be able to develop regenerative therapies using stem cells that can repair traumatic brain and spinal cord injuries,” she says.
Lee Ligon, assistant professor of biology, is using Thompson’s specialized growth substrates to further understand the stem cell niche. Little is known about why an undifferentiated stem cell will either divide to form another stem cell or begin to differentiate into another, more specialized cell. Current research supports the idea that the environment around the stem cell or the stem cell niche directs the stem cell’s development.
Ligon is manipulating the shape of growth substrates around cells to see how that affects their development. She is working to determine how a change in the shape of the stem cell niche could alter a stem cell’s fate.
A stem cell niche is believed to be similar to a hole in the dirt with stem cells resting at the bottom like small seeds, full of potential and ready to grow. The stem cells will either divide to become more undifferentiated stem cells or move toward the surface of the niche, becoming more differentiated as they get further outside the hole like a cellular sapling no longer a seed, but not yet a tree.
“The differentiation of stem cells is believed to depend in part on their geometry, in particular their orientation in space when they divide,” Ligon says. When they divide in a plane perpendicular to the bottom of the niche, the cells split horizontally, creating more stem cells. When that plane is parallel to the bottom of the niche, they split vertically, creating more differentiated cells.
Ligon is working to test the theory about the geometry of cell division by growing cells in bio-engineered micro-environments of different sizes and shapes. “If we can understand what causes normal healthy stem cells to differentiate, we can hopefully someday uncover the potential errors that occur in the division and differentiation process and cause disease,” she says.