Subject: [Homestead] Stem cells become spinal cord neurons
Date: Mon, 07 Feb 2005 08:49:34 -0500
ScientificAmerican.com
January 31, 2005
Scientists Switch Stem Cells into Neurons
Scientists have long been studying the process of how mammalian stem
cells differentiate to form specific types of brain cells. Researchers
are now reporting another small step toward understanding what
conditions are necessary for spinal motor neurons to form: they have
coaxed human embryonic stem cells to differentiate into one critical
component of the nervous system.
Su-Chun Zhang of the University of Wisconsin-Madison and his colleagues
exposed human embryonic stem cells to a variety of growth factors and
hormones in sequence in order to encourage them to change into motor
neurons. "You need to teach the [embryonic stem cells] to change step by
step, where each step has different conditions and a strict window of
time," Zhang explains. "Otherwise, it just won't work." The embryonic
stems cells first became neural stem cells then changed into the
beginnings of motor neurons before finally differentiating into spinal
motor neuron cells, the cell type that, in the human body, transmits
messages from the brain to the spinal cord. The newly generated motor
neurons exhibited electrical activity, the signature action of neurons,
and survived in culture for more than three months.